How to Build a Solar Hot Water System By

John Canivan

Printing January, 2004 Sunny Future Press, Wantagh, NY Copyright © John Canivan 2002

ISBN 0-9754980-0-2

All rights reserved. No part of this book may be reproduced or transmitted in any form or by any means electronic or mechanical without the express permission of the publisher. On line support is available from www.JC-SolarHomes.com. If you have any questions or comments about this book feel free to publish them on the JC Solar Collector Forum or join the Solar Energy group or send email to canivan@optonline.net.

How to Build a Solar Hot Water System is dedicated to: My devoted wife, who lovingly tolerates the chaos I create, and… Monday, a very special cat, who is now sleeping.

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If you have $2000 and a few weeks of labor to invest this book can easily save $50,000 or more in hot water. You folks with carpentry and plumbing skills have a

definite advantage. This book is also for anyone with a grasp of the English language willing to learn carpentry and plumbing skills. A good solar heating system is not free. It seems like it should be; after all heat from the sun is free why isn’t the solar heating system? Fossil fuel contractors throw in oil burners for free when they sign you sign up for a five-year contract. Why doesn’t Mr. Sunshine give us the same deal? I guess Mr. Sunshine is just a mean old man.

We are all part of a vast, interdependent universe. Energy for life is our birthright like the air we breathe or the water we drink. Our sun has enough energy to sustain us, and still we burn the fluid remains of our ancestors to stay warm. Buckminster Fuller, who coined the saying “Doing more with less,” compared fossil fuel with the starter motor of an automobile. He believed that the modern technological world we live in was started with a little boost from fossil fuel consumption. Once started technology should free us from dependence on non-renewable energy. Our starter motors are growing weary. It’s time to start the motor of social harmony, get back to our roots and welcome in the “Solar Age”.

SOLAR ELECTRICITY: The photovoltaic power industry has a long way to go before becoming a practical investment for the average consumer although some remote locations miles from the power grid find that it’s more practical to install

solar panels than have power lines run to their house. Government incentives and technological production breakthroughs are necessary before the photovoltaic industry blossoms. $5.00/watt is still too much for me. When the price comes down to $1.00/ watt give me a call. A typical $40,000 residential investment would take about 40 years to reach payback. This is of course assuming that $40,000 has the same value today as it would have forty years from now. Solar Electricity is a beautiful thing, but for most of us the time is not right. We’ll have to wait a little longer until this growing technology becomes feasible.

SOLAR HEATING Solar heating is feasible today. The average American

household consumes between 1000 and 2000 gallons of number two fuel oil per year. Efficient use of the sun’s energy could easily cut this consumption in half or eliminate it entirely. The heating of water is perhaps the easiest, most cost effective solar project a person can get involved with.

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TOOLS AND MATERIALS TOOLS: You will need a hammer, a table saw, a miter box or a miter saw, a drill, drywall bits, (1/8, ¼, ¾) drill bits, a 3/8 inch drill, a soldering torch and other soldering tools, tin snips, a hacksaw, and a paint brushes.

MATERIALS for collectors

1. Two rolls of 50-foot 20” aluminum flashing 2. Four .060-inch thick 4X8 sheets of Kalwall Sun-Lite Glazing from:

www.solar-components.com . 3. Twenty 1X4X8 pine with few or no knots 4. Four 3/8x4x8 CDX plywood 5. Four 1x4x8 sheets of isocynate insulation with foil backing 6. Sheet metal screws #10x1 7. One gallon of roofing tar 8. One gallon of oil base paint 9. Angle iron for mounting 10. Sixteen ¼ X 3 lag bolts, sixteen ¼ X 1½ inch machine bolts with nuts

and washers 11. 1 ¼ inch and 2 inch drywall screws 12. One pound of 1½ inch galvanized nails with small heads 13. PLUMBING SUPPLIES

a. Eight 3/8 to ½ adaptors b. Four ½ inch T’s c. Two ½ X ½ X ¾ T’s d. One ¾ inch T e. Four ½ inch unions f. Eight ½ inch elbows g. One ¾ inch street elbow h. One ¾ sweat to ¾ female pipe i. One pressure relief valve

j. Four sixty foot rolls of 3/8 ID copper tubing k. ½ - inch rigid copper tubing type L l. 3/8-inch flexible copper tubing 4(60’ rolls) m. ¾-inch flexible copper tubing 8(60’ rolls) DEPENDING n. ¾ - inch rigid copper tubing type L or M o. Solder and flux

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How to Build a Solar Hot Water System

Chapter I SOLAR HOT WATER SYSTEMS Theory

Passive hot water 9

Active hot water 10 Heat transfer 11 Flow rate dynamics

Parallel flow 13 Serpentine flow 14 Application Side joined collectors 15-16 Top/bottom joined collectors 17-18

Chapter II ABSORBER PLATE CONSTRUCTION

Theory 20 Materials 21 Pounding jig construction instructions 22 Absorber plate construction instructions 23-27

Chapter III COLLECTOR BUILDING INSTRUCTIONS Step 1. Cut framing boards 28 Step 2. Assemble frame 29 Step 3. Fasten collector bottom and sides 30 Step 4. Construct tube bending jig 31 Step 5. Bend copper tubing 32 Step 6. Install insulation 33 Step 7. Drill inlet, outlet and vent holes 34 Step 8. Install absorber plate 35

Step 9. Install serpentine tubing 35 Step 10. Install sweat union 38 Step 11. Cut serpentine tube supports 40 Step 12. Install tube supports 41 Step 13. Paint absorber plate 42 Step 14. Install Kalwall 42

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Chapter IV COLLECTOR MOUNTING Theory of orientation and pitch 44 Assembly of horizontal and vertical supports 45

Chapter V HOT WATER STORAGE Thermodynamic theory 46 Multi tank theory 48

Heat exchange coil theory 49

Chapter VI HEAT STORAGE VAULT CONSTRUCTION Step 1. Tank preparation 51 Step 2. 4X4 supports 51 Step 3. Bottom platform 51 Step 4. Placing tanks on platform 52 Step 5. Framing the storage vault 53 Step 6. Insulating the storage vault 54 Step 7. Installing sides 54 Step 8. Installing sheet insulation 55 Step 9. Making and installing the inner lid 55

Chapter VII HEAT EXCHANGE COILS Theory 56-60 Assembly 61 Inner lid construction and installation 63-65

Chapter VIII CIRCULATOR AND VAULT PLUMBING Mounting platform 66 Plumbing overview 67 Details of plumbing 68 Assembly 69

Chapter IX COLLECTOR PLUMBING Overview 70 Union T assembly 71 Main output junction assembly 72

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Main input junction assembly 73

Chapter X THE SENSOR SYSTEM 74

Chapter XI FILLING AND DRAINING THE SYSTEM 75-76

Chapter XII OTHER SOLAR APPLICATIONS 77

GLOSSARY 78-79

Author’s NoteAuthor’s NoteAuthor’s NoteAuthor’s Note 80

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I

SOLAR HOT WATER SYSTEMS

What once was a luxury is now a necessity. Billions of households have or would like to have running hot water. In 1970 a friend of mine left the civilized comforts of a New Jersey home to seek out and experience the free, wild wilderness of an Adirondack hilltop in upstate New York. Jack loved the country life and swore that he’d never leave his mountain retreat. He endured the cold winters without electricity and baseboard heating, but Jack still missed running hot water. When spring came he took a 300-

foot coil of black plastic tubing and connected one end to a spring high up on the mountain. He draped the remainder of the 300-foot coil on his roof and spread it out to cover as much surface area as possible. For a $50 investment and one hour’s worth of labor Jack had himself a bona fide hot water shower. He made good use of it whenever the sun was high on the mountain. I used it a few times myself. It works. The roof might look a little funny and the hot water would sometimes run out sooner than you’d like, but it did work when the sun was shining. When the sun disappeared the shower would get very cold. By the end of September water would freeze inside the exposed plastic tubing. You might be interested in a simple system like this if you enjoy taking showers when the sun shines. If you’re looking for a more sophisticated hot water system

you’ll need to invest more time and more money. This book briefly examines the possibilities of various hot water systems. If you

live in a warm sunny area a simple passive batch heater is probably all you’ll

need. If you’re interested in an automatic system that works well in cold climates

with a minimum amount of sunlight you’ll need an active array of flat plate

collectors along with a heat storage system. Parabolic-trough heat concentrating collectors are best suited for large scale power generation so they will not be explored for their domestic hot water application in this book.

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The construction of a cost effective solar hot water system from commonly

available construction and plumbing supplies is the main concern of this book. The only materials requiring a special order will be the Kalwall glazing and a differential sensor relay system.

For collector glazing you could use low iron glass, but it’s expensive, fragile and heavy. Thermo pane low iron glass is the best, but it’s also the most

expensive. A four by eight sheet of thermo pane is much heavier than a 4x8 sheet of Kalwall. I recommend that you stick with the Kalwall. It’s tough, light, resistant to UV degradation and easy to work with. For a storage vault I am suggesting that you use a series of tanks through which heat exchange coils are immersed. Fifty-five gallon drums make good storage tanks, but they must be waterproofed to prevent rust. Some people that I’ve corresponded with have used plastic drums. I guess that’s one way of eliminating the rust problem. If you have difficulty obtaining and rust proofing 55-gallon drums you could purchase standard water tanks new from a plumbing supply house or you could purchase used tanks from a metal salvage yard. You might even pick up a few used hot water tanks free around your neighborhood. People who convert from gas heat to oil heat no longer need their perfectly good gas hot water tanks. Keep your eyes out for discarded water tanks. Recycling is good for everyone and

you can’t beat the price. External heat exchange works great with these kinds of tanks. All you need

to do is wrap the lower area of the tanks with soft copper tubing, bind it tightly to the tank with bailing wire and chicken wire and then plaster the mesh to the tank with cement. Cement is an excellent conductor of heat. One inch of stuccoed cement should be sufficient. Just don’t forget to wrap your tanks in insulation when you’re done. If you decide to go with external heat exchange be sure to get in touch with me, and I’ll walk you through the process. I’m sure you’ll come up with your own ingenious methods of gathering and storing heat from the sun. The concepts and methods of construction explored in this book should be used as guidelines for your special project. Feel free to exchange your ideas and concerns with me. You can also post on the SOLAR HOT WATER

FORUM accessed from my home page at www.jc-solarhomes.com . And now let’s take a quick look at some popular solar hot water systems.

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PASSIVE HOT WATER

BATCH HEATERS In mild climates like coastal California or almost any place in Florida where freezing is a rare occurrence a simple passive batch heating system is all that’s necessary. The batch heater could be as simple as a water tank painted black. A more efficient system would enclose this black tank in an insulated box. Glass or some form

of glazing would be installed at an angle perpendicular to the sun’s rays. This is a practical, cost effective passive solar hot water system, ideal for mild climates. For more information about this system check out www.solarnet.org.

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ACTIVE HOT WATER Active solar hot water systems are designed for those less gentle climates. Although they are a bit more complicated and require electricity to run a circulator pump, active solar hot water systems harvest a lot of energy and save you money.

How much money will they save me on my fuel bill?How much money will they save me on my fuel bill?How much money will they save me on my fuel bill?How much money will they save me on my fuel bill? Good question. The answer to this question will of course depend on:

1. Your location

2. The orientation of your roof 3. The angle that you position your collectors 4. The number of collectors used 5. How well you insulate the ¾” heat transfer pipes 6. The size of your heat storage vault 7. The amount of insulation used on the heat storage vault 8. The amount of hot water used

You are avoiding my question.You are avoiding my question.You are avoiding my question.You are avoiding my question. OK it’s a fair question and I’m going to give you the best answer I can from data on my collector performance and other environmental data. For my four-collector system with a storage vault of four 55-gallon drums I estimate a minimum heat energy harvest of 60 fuel oil equivalent gallons per year per collector per year. At a value of $2/gallon I estimate that a four collector system like this should save at least $480 per year and pay for itself in less than 4 years at the current cost of materials if the price of fuel oil never changes. $500 savings per year on Long Island. But how about the cost of electricity used to harvest But how about the cost of electricity used to harvest But how about the cost of electricity used to harvest But how about the cost of electricity used to harvest heat from the sunheat from the sunheat from the sunheat from the sun???? I wouldn’t worry about that too much. An 85 watt Tyco circulator pump will consume about 10,000 watts worth of electricity in a year to run the system. At a cost of $.15/KWH the pump will use $1.50 worth of electricity per year.

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HEAT TRANSFER THEORY

Before diving into the building plans for an active solar hot water system I’d like to discuss a few basic concepts regarding light, heat and heat transfer. How does light make heat?How does light make heat?How does light make heat?How does light make heat? Most of the sun’s energy that makes the 93,000,000-mile journey is in the form of visible and ultraviolet light. Heat is produced when high frequency light is converted into low frequency infrared radiation. Ultraviolet and visible light easily passes through glass, however when they strike a darkened surface they are converted into long wave infrared radiation. The glass or special solar glazing traps these long waves. This is known as the greenhouse effect. CO2 is also capable of trapping long wave radiation. Small amounts of CO2 keep our planet nice and warm. Too much CO2 in the atmosphere may transform our forest into deserts. Is it not ironic that we are using the same effect to save the planet that is destroying the

planet? Now I understand the Greenhouse effect. Could you Now I understand the Greenhouse effect. Could you Now I understand the Greenhouse effect. Could you Now I understand the Greenhouse effect. Could you explain what heat is?explain what heat is?explain what heat is?explain what heat is? Heat is the product of temperature and mass. Temperature measures the average motion of molecules. When light strikes an object it causes the molecules to

vibrate faster. Intense light can ignite a log or melt steel. The faster an object vibrates the hotter it becomes. It’s as simple as that. OK I get it. Light causes molecules to move faster. So OK I get it. Light causes molecules to move faster. So OK I get it. Light causes molecules to move faster. So OK I get it. Light causes molecules to move faster. So how do these fast moving light excited molecules get how do these fast moving light excited molecules get how do these fast moving light excited molecules get how do these fast moving light excited molecules get into my hot water system?into my hot water system?into my hot water system?into my hot water system? They don’t. If they did you would have a contaminated system and you’d get sick and die, because collector fluid usually contains antifreeze. The molecules that are excited by the sun never enter your domestic hot water. Only molecular movement is transferred in the double insulated flat plat plate collector system that I am proposing. Wouldn’t it be easier to use plain old ground water for Wouldn’t it be easier to use plain old ground water for Wouldn’t it be easier to use plain old ground water for Wouldn’t it be easier to use plain old ground water for collector fluid then you wouldn’t need antifreeze? collector fluid then you wouldn’t need antifreeze? collector fluid then you wouldn’t need antifreeze? collector fluid then you wouldn’t need antifreeze? In gentle climates perhaps, however if you travel north of Georgia the batch tank would lose too much heat in the evening to be practical. Under extreme conditions the water in the tank might even freeze. For cold climates it is always best to separate the heat collection area from the heat storage area.

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How about thatHow about thatHow about thatHow about that drain away system? drain away system? drain away system? drain away system? Good point. There is another type of system called the DRAIN BACK system that allows heated water to drain back into a holding tank when sensors indicate that no heat gain is possible. Some of these systems employ heat exchange tanks and some

use the solar heated water directly. These systems do save that hot water in the pipes with a system of automatic valves and relays, but if a valve gets stuck you might have a problem. Drain Back systems also use high head expensive pumps that require more energy than closed loop circulator pumps. OK! You convinced me. Should I get my tools? I feel OK! You convinced me. Should I get my tools? I feel OK! You convinced me. Should I get my tools? I feel OK! You convinced me. Should I get my tools? I feel like hammering and drilling and sawing and screwing.like hammering and drilling and sawing and screwing.like hammering and drilling and sawing and screwing.like hammering and drilling and sawing and screwing. That’s good. Hold onto these feelings a bit longer. I want to be sure you understand a few things about fluid mechanics. Forget it. I have a friend who is still baffled by the Forget it. I have a friend who is still baffled by the Forget it. I have a friend who is still baffled by the Forget it. I have a friend who is still baffled by the concept of concept of concept of concept of fluid mechanicsfluid mechanicsfluid mechanicsfluid mechanics and he spent four years of and he spent four years of and he spent four years of and he spent four years of intense study at R.P.I.intense study at R.P.I.intense study at R.P.I.intense study at R.P.I. Come on, it will be fun. Think of it as plumbing 101. That sounds less threatening. I’ll give it a tThat sounds less threatening. I’ll give it a tThat sounds less threatening. I’ll give it a tThat sounds less threatening. I’ll give it a try.ry.ry.ry. That’s the spirit. I’ll make this as painless as possible and even throw in a few pictures to liven things up a bit. On the following pages I wish to compare and contrast two types of flat plate collectors, the parallel and the serpentine. Since the parallel collector is the most popular commercially available system I’ll discuss this one first.

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FLOW RATE THEORY PARALLEL FLOW DYNAMICS

This parallel collector is designed to transport collector fluid from the bottom of the collector to the top via a network of parallel pipes. Notice that the top and

bottom pipes are larger than the vertical pipes. There is a reason for this. Fluid mechanics favors an increased flow rate for the end pipes. This is because incoming fluid pressure is greatest at the base of the first pipe and outgoing fluid pressure is smallest at the top of last pipe. If the top and bottom pipes are large the pressure difference is moderated and the flow rate in each of the parallel pipes is more uniform. These collectors may be connected in series because the top and bottom distribution tubes are so large. It is unfortunate that the flow rate is minimal at the center of the collector where most of the heat is concentrated. Other problems associated with the parallel flow include cost and leaks. Half inch and two inch copper tubes are expensive; also there is a leak risk from the dozens of expensive special T fittings. One small, undetected leak on one T fittings could become a catastrophic mess.

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SERPENTINE FLOW DYNAMICS

The serpentine collector consists of one long continuous flexible tube so there is no problem with uniform flow rate. The size of this flexible tubing is an important consideration. Quarter inch copper tubing is inexpensive, however it restricts the

flow rate too much. Half inch flexible tubing is difficult to bend and fairly expensive. 3/8 inch tubing is just right for the money. It has a reasonable flow capacity, low cost, and ease of fabrication. What more could one ask for? The main problem with a serpentine collector is flow rate restriction. Even the larger half inch copper tubing restricts flow rate too much and puts an unnecessary burden on the circulator pump. Connecting the serpentine collectors in parallel alleviates this problem. A two-collector system works fine. A four-collector system works even better. It is very important to bend this 3/8 copper tubing carefully to avoid kinks. This will insure that the flow rate is uniform throughout the serpentine collector array hooked in parallel. The following pages demonstrate how two, four and eight serpentine collectors should be hooked in parallel to maximize uniform flow rate and minimize fluid pressure on the pump and pipes. Collectors may be joined from the tops and bottoms or from the sides. Side joined

systems are a bit easier to construct so I have decided to employ this method in my construction plans. Two, four and eight side-joined collector systems are illustrated.

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Top and bottom joined systems are also illustrated. Please note that my assembly instructions call for side joined systems. TWO COLLECTORS TOP AND BOTTOM JOINED

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FOUR COLLECTORS TOP AND BOTTOM JOINED

EIGHT COLLECTORS TOP AND BOTTOM JOINED

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Now that we know what the serpentine collector looks like lets see if we can pop a few together. My construction building plans are for the side joined systems, however you can easily modify these plans if you decide to construct a top and bottom joined system. Order the necessary Kalwall glazing now, if you haven’t already done so, as it may take a few weeks to receive your order. I recommend that you purchase the .060 inch thick Kalwall even though it costs a little more than the .040-inch stock. You will need one 4X8 sheet for every collector you

build. You can save a little money if you purchase a fifty-foot roll. The fifty-foot roll is good for 6 collectors. If you are using a 4-collector system you might be able to talk a neighbor into purchasing two of your collectors to pay for the entire project.

To order online go to www.solar-components.com and tell them JC sent you.

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II

Absorber Plate Construction

Solar Collectors would not be very practical without absorber plates. Absorber plates increase the surface area exposed to sunlight. More than 700 linear feet of copper tubing would be required to cover the same surface area that could be covered with 60 linear feet bonded to a well-constructed absorber plate. Copper absorber plates facilitate the soldering of copper tubes, but they are expensive, heavy, difficult to fabricate and unnecessary. Aluminum absorber plates are less expensive, lighter, and easy to fabricate. You should be relieved to know that my design calls for aluminum absorber plates. Did you know that aluminum is a superior conductor of heat? That’s nice to know but how do you expect me to solder That’s nice to know but how do you expect me to solder That’s nice to know but how do you expect me to solder That’s nice to know but how do you expect me to solder a copper tube to an aluminum plate?a copper tube to an aluminum plate?a copper tube to an aluminum plate?a copper tube to an aluminum plate? I don’t. A metallic bond of copper to aluminum requires a special helium arc set up. The process is time consuming and expensive. We’ll be using tar. Sounds a little sticky to me. Sounds a little sticky to me. Sounds a little sticky to me. Sounds a little sticky to me. It is sticky. That’s the point. Tar also provides a good conducting medium. If you have ever walked on a hot tar roof you’ll know what I mean. OK tar sounds good. How large sOK tar sounds good. How large sOK tar sounds good. How large sOK tar sounds good. How large should this absorber hould this absorber hould this absorber hould this absorber plate be?plate be?plate be?plate be? The aluminum plate should cover the largest possible area inside the collector. The inside dimension of a 4X8 collector would be 46½” X 94½ “. The width of the absorber plate should be less than 46½ ” to accommodate the semicircle bends of the copper tube.

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So… the width of the absorber plate should be about 40 inches. The starting length of the plate should be 100 inches. After 16 grooves are pounded into the aluminum sheet the length should shrink about 6 inches. So … the finished absorber plate should measure about 40 X 94 inches. You may have difficulty finding sheets of aluminum that are 40 X 100 inches. Two 20 X 100 inch sheets work fine. If you purchase a 50-foot roll of 20-inch aluminum flashing you will have enough for three collectors. A 67-foot roll would

be just right for four collectors, but I doubt that such an animal is commercially available. You’ll need two 50-foot rolls for a four collectors, or three 50-foot rolls for eight collectors. A fifty-foot roll of 20-inch aluminum flashing costs about $30.

What else will I need?What else will I need?What else will I need?What else will I need? Good question. Might as well get everything you need in one trip.

Tools and Materials for Absorber Plate Construction

1. Two 50-foot rolls of 20-inch aluminum flashing for four collectors. 2. Four 1X6X8’s common pine. (Actual size ¾” X5½” X8’) 3. Two 7/16 inch steel rods. 4. Heavy hammer. 5. Tin snips. 6. One pound of 1 ¼ - inch drywall screws. 7. Hacksaw.

8. One gallon of roofing tar and a throw away brush. Are we ready?

Let’s go.

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I recommend that you work on a level concrete floor. First you’ll need to build what I call a pounding jig. This jig will be used to pound 16 grooves into each 20 X 100 inch sheet of aluminum.

Pounding Jig Construction Instructions

1. From the wood that you purchased make four 1X6X4’s and seven 1X6’s 20

inches long. 2. Take the remaining piece of 1X6 and cut off a ½ inch strip. The width of this strip should be precisely ½ inch. It will be used as a reference spacer.

3. Rip the remaining piece in half to make two 1X2’s 20 inches long 4. Place the eight 1X6X4’s in a row on top of the concrete floor with half-inch spaces between them. This will be the base of the pounding platform. The base platform should measure 24 inches by 48 inches.

5. Screw a 1x2 onto one end of the base platform with drywall screws perpendicular to the base platform. Now secure a 20-inch 1X6 ½ inch from the 1X2. Use the reference spacer between the 1X2 and the 1X6 to get accurate spacing. Be sure all the 1X6 boards are also perpendicular to the base platform and spaced ½ inch apart.

6. Fasten the top layer of boards to the base platform with 1¼-inch drywall

screws. The most important consideration in the construction of this jig is the spacing between the boards. The ½ inch spaces should be centered 6 inches apart, and the pounding jig should look something like this when you’re done. I will now refer to the spaces between the boards as slots.

Now for the pounding

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1. First cut some aluminum sheets 100 inches long. You will need eight 20X100 inch strips for four collectors.

2. Cut a 7/16” steel rods in half so that you have two rods 24 inches long. 3. Lay the aluminum sheet on top of the pounding jig so that one end of the sheet extends 3 inches beyond the center of the first space. It is important to get off to a good start so I recommend that you center the aluminum sheet on the pounding jig. The edge of the aluminum should be parallel with the edge

of the pounding jig platform. When the sheet of aluminum is properly centered with one end protruding 3 inches from the center of the first space place your knee on the aluminum to hold it in place and carefully press the rod into the first ½ inch slot like this:

4. Now you must pound the rod into the slot to create the first groove like this:

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5. Pound the rod till it is flush with the top of the aluminum like this:

6. Now place plywood or a nice flat board on top of the imbedded steel rod and pound the board till you are sure that the rod is flush with the top of the aluminum. I call this board the stabilizer board.

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7. Now put some pressure on the stabilizer board to hold the aluminum in the correct position and move on to the next space. Press the rod into the second slot and pound it flush like you did to create the first groove.

8. Now slide the stabilizer board over second groove and pound away until your satisfied that the rod is flush with the top of the aluminum.

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9. Keep on trucking. You’ve got 14 more grooves to make before this absorber plate is complete.

10. There are only eight slots for making grooves on this pounding platform, so

you will need to slide the aluminum down after making the first eight groves. Place the last two groves inside the first two slots. Be sure to line up the sheet parallel with the pounding platform. Now press rods into the last two groves that you made on the first run. Hold the rods in position with the stabilizing board and your knee and continue the process until you make all 16 groves.

Congratulations! You have just made your first absorber plate. Now all you have to do is pound out 7 more and you’ll have enough for a four-collector system.

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The absorber plate should look something like this:

Guess it might seem a bit crude, but believe me it works. Once the serpentine tube is bonded to the groove with tar and the absorber plate is coated with a lampblack tar coating it will look something like this close up. Notice how the absorber plate wraps around the copper tubing.

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III COLLECTOR BUILDING

INSTRUCTIONS Before embarking on this project you might consider clearing out the garage or finding another suitable work area. STEP ONE Cut framing boards

Take those carefully selected, straight 1X4’s with few or no knots and miter the ends. The sidepieces should measure eight feet from tip to tip. The top and bottom pieces should measure 4 feet from tip to tip. Paint the mitered end grain with your oil base paint before assembling the frame. This is an excellent weather proofing precaution.

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STEP TWO Assemble the frame

Find a nice hard level surface and assemble the frame like this. Be sure the length is eight feet between the outside corners and the width is four feet between corners. You could attempt to screw the corners together if you like, but you may find it difficult to hold them in place while driving a screw. I like to gently throw the 4X8 CDX plywood on top of the 1X4’s. One or two of the 1X4 may fall down, but they can easily be put back in place. The important

thing is to line up the 1X4’s under the plywood one at a time. Make sure the outside edge of the 1X4 is flush with the plywood and the corners of the plywood line up with the outside tips of the 1X4’s.

Once the plywood is nailed or screwed into the 1X4’s the corners may easily be joined with 2” drywall screws.

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STEP THREE Fasten the collector bottom and sides

Carefully place the CDX plywood on top of the 1X4’s. Be sure that the outside corners of the 1X4’s meet the corners of the CDX plywood before nailing down the plywood bottom of the collector. Place the 1½-inch nails about a foot apart and throw in a few more near the corners. Predrill 1/8-inch holes into the 1X4 corners and screw in some 2-inch drywall screws to secure the corners.

Make all your collector frames at once and then paint them inside and out with an oil base paint of your choice. Now take a break. You’ve earned it, and besides you’ll have to let the paint dry for a few days before giving a second coat. If it becomes impossible to wait for paint to dry you could spend some time working on the 3/8 inch copper tube-bending jig.

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STEP FOUR…. Construct tube-bending jig Take those four 1X6X8’s and cut them in half so that you have eight 1X6X4’s. Cut semicircles on the ends of the 1X6 boards and then make 8 boards like this one.

Now cut each of these boards in half, and flip a collector frame over so that its plywood bottom faces up. Center the bending jig boards on top of the collector bottom in the manner demonstrated below. Use a half-inch reference spacer board to position the bending jig boards so that they have a half-inch gap between them and screw them into the CDX plywood with drywall screws. Two screws in each

board should be sufficient. Use a carpenter’s square to trace out guidelines on the collector bottom. This will help you secure these 1X6 boards in this manner demonstrated.

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STEP FIVE Bend copper tubing. If you have carefully laid out the bending jig and have spaced the bending jig boards correctly you should have no difficulty bending the copper tubing. Keep the tubing snug when you press it down into the grooves, but do not put kinks in the tube. Kinks restrict the flow rate and lower collector efficiency. If you do put a few small kinks in the tubing don’t shoot yourself. With a little TLC you can squeeze kinks out with the help of vice grip pliers.

You will be bending a sixty-foot coil of 3/8 inch ID copper tubing into the tube bending jig slots from one end of the jig to the other. A friend may prove useful. If you don’t have a friend to help you may wish to hold the start end down with a board and a few screws. Start the tube about a foot from the top of the first loop so that you have enough tube for the entire serpentine bend. The bent tube will look something like this when you are done:

Find a good place to store your serpentine tubes. DON’T KINK THEM. Give all the collector frames at least two good coats of oil enamel paint. After the collector frames have thoroughly dried you can check yourself into a nearby mental hospital. Say hello to my wife while you’re in there. Only kidding. If you have come this far

I think you’ll make it. Hang in there you are doing fine. Now go on to step 6.

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STEP SIX. INSTALL INSULATION AND SUPPORT SQUARES

Turn a collector right side up and install a 4X8 sheet of one-inch ridged isocynate

insulation with a foil back. Place the insulation inside the collector foil side up and trim off the excess with a drywall knife so that the insulation fits nice and snug. MARK INSULATION: Mark the insulation where the copper tubes will go. The lines should be 6 inches apart. The first line and last line should be 2¼ inches from the inside edge of the collector frame. Now rip 5¼-inch strips of ½- isocynate insulation and glue these pieces (with contact cement to the back of the absorber plate as illustrated below. These squares will help position and support the absorber plate.

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STEP SEVEN Drill inlet, outlet and vent holes The absorber plate grooves will hold the serpentine copper tubing that you bent. Before unrolling these groovy absorber plates I’d like you to drill four ¾-inch holes into the sides of your collector frame. The inlet and outlet holes should be centered to accommodate the inlet and outlet positions of the serpentine tube. Center the inlet and outlet holes 3 inches from the collector corners and about 2

inches down from the top rim of the collector frame. A distance of 90 inches must separate the inlet and outlet holes. You will also need a few vent holes in the bottom side of your collector to vent trapped collector moisture. Vent holes should be centered on the bottom side of the collector one foot from the corners and 1½ inch down from the collector’s top rim. Center the vent holes one inch down from the top and one foot over from the bottom side corners. The ¾-inch holes may seem a bit large but there is a reason for this. Half inch copper union connectors will be inserted into the inlet and outlet holes. The space between the tube and the wood will be filled with clear silicon caulking.

These vent holes are for the right collector. The left collector will have vent holes on the other side. All vent holes should be on the bottom side of the collectors.

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STEP EIGHT Install absorber plate

Now unroll two absorber plates into the collector body, groove side up and overlap them in the center of the collector body. Overlap the absorber plates so that their outside edges are 4 inches from the inside edges of the collector sides. A distance of 90 inches should separate the end grooves. You may wish to trim the ends of the flashing to fit the collector body.

STEP NINE Install serpentine tubing If you did a good job bending the 3/8 inch tubing, installing it into the collector

body will be a piece of cake. Handle the tubing with care. You have come this far without a kink; why spoil it now? Gently glide the tubing into position. This serpentine assembly should measure about 94 inches long and be 45½ inches wide.

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Congratulations! Your collector should look something like this after the serpentine tube is inserted. If you examine this three dimensional collector closely you will notice that it has 14 groves instead of 16. This is merely a pictorial representation of the actual collector. Your absorber plate should have sixteen groves and the serpentine tube should fit into these groves, if they don’t, make the necessary adjustments before continuing. Do not press the tubes into the grooves yet.

Join 1/2 ID copper pipes to the 3/8 ID copper tube with adapter sweat fittings and

allow the ends to protrude through the predrilled ¾ inch holes. The solid protrusions from the collector represent ½-inch copper tubes. These tubes will later be trimmed to fit sweat unions that will fit snug against the side of the collector.

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What is a sweat union?What is a sweat union?What is a sweat union?What is a sweat union? A sweat union is a special fitting that allows copper pipes to be joined with compression nuts. It looks like this:

First copper tubing is soldered to the union fittings like this:

Next the union nut is tightened onto the union fittings to join two copper pipes like this:

The nice thing about unions is that they are temporary connections. If you decide to move your collectors to a different location some day, unions facilitate the move.

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STEP TEN Install sweat unions Now we shall connect some unions to the inlet and outlet ends of the ½-inch protruding copper pipe. Before doing this trim the ends of the copper so that it extends only ¼ inch beyond the outside of the collector. Mark the pipe before sliding it out and cutting it. You will need to push the inlet and outlet ends of the tube beyond their natural resting position in order to trim them to the proper length

and to insert the union fittings. To do this without kinking the tube carefully lift the tube bends over the collector rim and slide the inlet and outlet ends out. Now slide the female union nut over the ½-inch inlet end and be sure that the threads are facing away from the side of the collector. Slide the connecting nipple onto the end of the pipe and solder it in place. The back of the female union nut should rest flush with the outside of the collector after you put the serpentine tube back into the collector body. Do the same for the outlet end. The assembly should look like this:

After the serpentine tube is put back inside the collector body the union nut should look like this:

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The mounting and joining of collectors on the roof will be easy if you do a good job of fastening unions to the inlet and outlet ends of the collectors. A ½-inch T with two joining nuts and copper tube extension may be assembled on the ground to facilitate the collector mounting process on the roof. This assembly looks like this:

This assembly will later be used to join two collectors in parallel. Two inlets are joined at the bottom and two outlets are joined at the top with unions and T fittings. Don’t worry about this now. Let’s finish building our collectors first. Next we will build a few supports to hold the serpentine tube firmly inside the grooves.

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STEP ELEVEN Cut serpentine tube supports Rip one 1 X 4 X 8’s in half so that you have two 1 X 2 X 8”s. Rip another 1X4 so that you have a 2½” piece and a 1” inch piece. Put a beveled edge on the 1X2’s. These boards will be used to hold the serpentine copper tube in place. You will need to trim these boards to fit nicely into the collector body, but let’s worry about that later.

That was easy enough. Don’t you wish life could be this easy?

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STEP TWELVE Install tube supports Press the serpentine tube into the absorber plate grooves. Tube supports hold the tubes in place and press them tight into the absorber plate grooves. You may need to notch the bottom of tube support by the inlet and outlet holes. The beveled edge is not entirely necessary. It is just a little finishing touch that allows more light to strike the collector. The beveled edge should slope toward the center of the collector.

Now cut the side supports to fit inside the collector body. They should be about 94 ½ inches long. Screw them into the side of the collector from the inside with 1¼-inch drywall screws. Press the supports into the edge of the tubing to hold the tubing snug inside the absorber plate groove. Now install the central support, 94½ X 2 inches. This support like all the supports should stand upright. Center this support so that the top edge is flush with the top edge of the collector. Drill some 1/8-inch holes through the sides of the collector before joining the central support with 2-inch drywall screws. One screw in each end is enough. To stabilize the central support screw one 3” drywall screw into the center of the central support through the CDX plywood bottom. Do not drill through the copper tubing and do not over tighten this screw. Snug is fine. It should look something like this when you’re done:

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STEP THIRTEEN Paint the absorber plate So far so good: the copper tubing is secured in place and you are almost ready to nail down the Kalwall glazing and break for lunch, but there is one picky thing that we should take care of before we batten down the hatch. Paint the grooves with a mix of tar and mineral spirits, mostly tar. The tar will bond the copper to the aluminum and enhance the conduction of heat from the absorber plates. I suggest that you paint all the installed absorber plates at one time.

It’s best to lay them out flat in a sunny spot where they can dry easily before giving the final coat of absorber paint. You could buy some expensive selective coating if you like or you could mix up a batch of my top-secret absorber paint and save a lot of money. It consists of lamp black, tar and mineral spirits. Equal volumes of each work good for me. You’ll need about a gallon of the stuff. (Lamp Black can be purchased as a masonry supply. It’s used to color cement.) Leave the installed, painted collectors in the direct path of a hot sun for a few days to let them dry out.. STEP FOURTEEN Install Kalwall You will need four ½ X ¾ inch painted strips. Miter the ends so they fit together as demonstrated in the picture below.

Place the 4X8 sheet of Kalwall glazing on top of the collector. Carefully center this sheet and temporarily tack down one edge. Use a few # 4 finishing nails through a scrap piece of ½ inch strip of wood. Do not drive these nails home because you will be removing them shortly, they are used to hold the Kalwall in place while you run a bead of clear silicon caulking along the edge of the collector under the glazing. You might want to have a friend hold up the Kalwall while you apply the bead of caulking. Next run a thin bead of caulking on the top edge of the glazing and push the ½ X ¾ inch top trim into the wet caulking and nail it down with #4 finishing nails. Remove the temporary trim, and caulk the remaining edges of the collector in a like manner. Now nail down side and top pieces. The center top trim should not be nailed. Caulk under the center strip, press the center strip into the caulking, drill

1/8 inch holes evenly spaced across this strip and screw it down with ¼ inch round head brass wood screws. You are almost finished. As long as you have the caulking, squirt some in the inlet and outlet holes to seal the tubing in place. If you have some ½ inch copper tubing handy, cut off a few one inch pieces, apply a little silicon caulking to the vent holes and shove the tubes into them. Allow each of the tubes to protrude about ¼ inch.

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CONGRATULATIONS! You have just built your first serpentine solar collector. The others should go easy now that you have the hang of it. Your finished collector should look something like this. The top center strip is not necessary. If you decide to include this strip seal the underside with silicon and screw it down carefully.

Build three more and then we’ll mount them on your roof.

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IV

MOUNTING THE COLLECTORS

The problems associated with installing flat plate collectors vary with latitude, orientation, pitch and type of roof. Installing four flat plate collectors on a flat roof in Ecuador would be less challenging than installing the same collectors on a slate roof in Maine with an easterly orientation. ANCHORING THE ANGLE IRON The one thing all installations do have in common is their need to be anchored securely. Angle iron is commonly used to facilitate the process. Typically two strips of angle iron are bolted into the roof and one strip of angle iron is bolted to the collectors. Between the roof angle iron and collector angle iron additional angle iron is used to elevate the collectors into an optimal angle for solar

collection. ORIENTATION In North America the optimum orientation needed to maximize solar gain would of course be that of a Southerly direction. When radiant solar energy is perpendicular to a surface, heat gain is maximized. If you live in a town centrally located in the US the optimum angle from the horizon pointing toward the equator would be about 45 degrees. If you live in Florida you might tilt your collectors 40 degrees and if you live in Maine you might tilt them 50 degrees. If you decide to maximize your heat gain in the summer you should lower your collectors a bit, but generally speaking 45 degrees is a good year round angle for the central latitude of the USA. If you are centrally located in the United States and have a roof with a pitch of 45

degrees facing south you are an ideal candidate for a simple solar collector installation. Angle iron should still be used to simplify the installation. It is best to position a few pressure treated 1X4s under the angle iron. For two collectors use four 1X4X4s: two placed under the bottom roof angle iron support and two positioned under the top roof angle iron support. The space between the 1X4s allows water to easily drain off the roof. Bolt the angle irons through the 1X4s, through the roof and into the roof rafters. For two collectors you will need eight ¼ X3 inch lag bolts, two bolts for each 1X4. To precisely locate a roof rafter from the outside of a roof you should drill a small hole from the inside. Don’t worry about the tiny hole. You can fill it with silicon caulking later.

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I like to use galvanized angle iron with pre-drilled holes. The ones shown here are oversized for illustration purposes. Notice the orientation of the bottom angle iron. Your collectors will rest on this slot so be sure to bolt the angle iron securely to the roof joist. The top angle iron should be secured in a like manner. Once you decide on the best elevation for the collectors you could cut some angle iron elevation supports. You will need 4 one-inch machine bolts with nuts and washers to secure

the roof angle iron support to the collector angle iron support.

After the supports are secured, slide the collectors onto the bottom angle iron and let them rest on the top support.

Secure the collectors temporarily with a few ¼X1 inch lag bolts through the angle iron supports. Before hooking up the collectors with plumbing you should build the storage tank facility.

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V HOT WATER STORAGE

All that hot water from the sun won’t help you take a bath on Saturday night if you don’t have a heat storage vault. In the past I have made the heat transfer storage vault with an 80-gallon water tank by wrapping it in copper tubing, chicken wire, bailing wire and cement. It’s messy but it works great. You could do it this way if you like. If you feel like going with cutting edge technology I’ll have to give you a little quiz before continuing. How well do you understand thermodynamic theory? What is thermodynamics? Haven’t I suffered enough?What is thermodynamics? Haven’t I suffered enough?What is thermodynamics? Haven’t I suffered enough?What is thermodynamics? Haven’t I suffered enough? Thermodynamics is the study of heat transfer. Answer this question correctly and I will never ask you another. Promise?Promise?Promise?Promise? Promise. If you want cutting edge you should understand something about thermodynamics. This question should help clarify some basic principles of heat

conservation and heat loss. Lay it on me.Lay it on me.Lay it on me.Lay it on me. Ralph goes to a diner and orders a cup of coffee. He tells the waitress that he wants his coffee hot and light. The waitress pours him a cup of scalding hot coffee and points to the creamer. Ralph realizes that he needs to use the washroom, but he wants his coffee to be as hot as possible when he returns. The question is: Should Ralph add the cream before or after the trip to the washroom? Beats me. How did your wife answer this question?Beats me. How did your wife answer this question?Beats me. How did your wife answer this question?Beats me. How did your wife answer this question? She said he should put a saucer on it. I like that answer.I like that answer.I like that answer.I like that answer. Me too. It demonstrates an understanding of heat conservation through the use of insulation, but you and my wife are both avoiding the question. Want to take a stab

at it? OK! I say he should add the cream when he returns.OK! I say he should add the cream when he returns.OK! I say he should add the cream when he returns.OK! I say he should add the cream when he returns.

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Wrong! How come?How come?How come?How come? Let’s think about this. We are concerned with heat loss. Which system will cool

down at a faster rate? A small volume of scalding hot black coffee… or A large volume of less hot light coffee

The small volume of scalding hot black coffee will cool down at a faster rate than the large volume of light coffee because the temperature difference of the black coffee and the air is greater. Large volumes also cool down slower than small volumes; therefore if Ralph adds the cream to his coffee before leaving he’ll return to the hottest cup of coffee possible. OK! Good for Ralph. He got a hot cup of coffee. What does this have to do with solar hot water storage? I thought you’d never ask. Solar hot water systems are basically systems designed to transfer heat from the sun into a heat storage vault. The heat storage vault is used to preheat ground water before it enters your regular hot water heating system. Remember how Ralph’s hot coffee cooled at a faster rate than his less hot coffee? The same principle of cooling applies to heating.

PRINCIPLE Heat transfer rate is maximized when the temperature

difference between objects is the greatest. THEREFORE: Heat is transferred at faster rate to the bottom of a tank than to the top of a tank, because the bottom of a tank of water is colder than the top. This is true because hot water is lighter than cold water. Cold water sinks, hot water rises. THEREFORE: Cold water fed into a collector will transfer more heat from the sun than hot water. THEREFORE: If the hot water storage tank is too small the temperature difference between the fluid entering and leaving the collector will soon become negligible and heat transfer will be minimized. HOWEVER: If a tank is too large it may never or rarely reach the desired temperature even if one takes advantage of the layering phenomena of hot and cold

water.

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MULTIPLE TANK STORAGE SYSTEM Taking all of these concepts into account we can design a Heat Storage Vault that will maximize heat transfer by using multiple tanks.

Tank 3 would always be the warmest because this is the first tank used to transfer collector heat by pumping hot collector fluid through a heat transfer coil. The second tank is heated in a like manner though it will never get as hot as the third tank. Call tank 2 the warmer tank. Tank 1 is designed to suck the last bit of heat from the already cooled collector fluid. This is the warm tank. Collector fluid returned from this tank will be nice and cold and ready for efficient heat transfer when it’s returned to the collector. This series of tanks is designed to preheat water in three successive stages. This minimizes heat loss in tank 3 and delivers the hottest possible preheated water.

Notice that the collector fluid coils are located near the bottom of the tank and the domestic hot water coils are located near the top of the tank. Why is that? That’That’That’That’s because heat from the collector fluid is best s because heat from the collector fluid is best s because heat from the collector fluid is best s because heat from the collector fluid is best transferred into the coldest area of the tank and the transferred into the coldest area of the tank and the transferred into the coldest area of the tank and the transferred into the coldest area of the tank and the highest temperature possible for heat extraction into highest temperature possible for heat extraction into highest temperature possible for heat extraction into highest temperature possible for heat extraction into domestic hot water is near the top of the tank.domestic hot water is near the top of the tank.domestic hot water is near the top of the tank.domestic hot water is near the top of the tank. Very good! I’m impressed. How’d you like to teach a course in thermodynamics? No thanks, but I do have a question for you… What is a No thanks, but I do have a question for you… What is a No thanks, but I do have a question for you… What is a No thanks, but I do have a question for you… What is a heat exchange coil?heat exchange coil?heat exchange coil?heat exchange coil? Good question. The diagram above is very simplistic with straight tubes in the area that would be best for heat collection. The problem with this over simplistic

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diagram is that it wouldn’t work very well because there isn’t enough surface area for good heat transfer. A heat exchange coil is an excellent tool for exchanging heat in a small area like the inside of a 55-gallon drum. It looks something like this:

Where do I get these heat exchange coils?Where do I get these heat exchange coils?Where do I get these heat exchange coils?Where do I get these heat exchange coils? You make them. You’re killing me, man. My knuckles are still sore from You’re killing me, man. My knuckles are still sore from You’re killing me, man. My knuckles are still sore from You’re killing me, man. My knuckles are still sore from bending those serpentine things for the collectors. bending those serpentine things for the collectors. bending those serpentine things for the collectors. bending those serpentine things for the collectors. Oh don’t be such a crybaby. It’s easy. You’ll be using flexible, pre-coiled copper tubing. All you have to do is

cut off a few pieces, make a few adjustments and do a little soldering. Anyhow don’t worry about heat exchange coils right now; we’ll get involved with them when we discuss plumbing. How are your carpentry skills? Good.Good.Good.Good.

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If I asked you to frame out a box three feet high with an inside measurements of 100 inches long and 28 inches wide would you be able to do it? I think so. What should I use to build the frame? I think so. What should I use to build the frame? I think so. What should I use to build the frame? I think so. What should I use to build the frame? 2X3’s, 1X4’s or 2X4’s.2X3’s, 1X4’s or 2X4’s.2X3’s, 1X4’s or 2X4’s.2X3’s, 1X4’s or 2X4’s. Let’s use 2X4’s spaced 16 inches apart so that we may later add insulation. The size of your particular heat storage vault will vary depending on the number and size of the tanks that you use, but the basic structure will be the same. Do you think you could adjust the size of your storage vault based on the particular size of the tanks you get? I think I could.I think I could.I think I could.I think I could. I’m sure you can. I have the utmost confidence in your ability. Let’s get to work. The tank vault instructions are for a three-tank system. I recommend that you build a four tank system or larger for a four collector array.

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VI HEAT STORAGE VAULT CONSTRUCTION

STEP 1. Tank preparation Gather up some water tanks. I recommend that you that get four 55-gallon drums for a four-collector system. They must be waterproof and rust resistant. If they are not rust resistant you must paint them with two or three coats of polyurethane. Let the paint dry thoroughly between coats. STEP 2. 4X4 supports Cut eight 4X4s 7 inches longer than the diameter of your tank. Lay them out on your basement floor where your vault will go. Fill the spaces between the 4X4s with sheet insulation after you position them correctly. You should locate the vault near the oil burner to facilitate the plumbing hookup.

STEP 3 Bottom platform If you would like to use the heat storage vault to heat water and also heat your house leave a four-inch gap between the tanks and also a leave a four-inch gap between the tank perimeters and the inside of the heat storage vault. Measure the largest diameter of your tanks. So if your tanks are 24 inches in diameter and you’re doing the three-tank system cut a piece of ½ inch CDX plywood 32X88 inches. Now place the plywood platform onto the 4X4s as illustrated on the following page. It is not necessary for the edge of the plywood to meet the edge of the 4X4s. The 4X4s are used to support the weight of the tanks. Run a few screws through the plywood into the 4X4s to hold it in position while you frame the walls

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THE BOTTOM PLATFORM

STEP 4 Placing tanks on the platform Place the tanks on the platform to make sure you measured everything correctly. You should have a four-inch border from tank to the edge of the platform.

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STEP 5 Framing the storage vault walls. Walls are easy to frame so get out those 2X4s. The first thing to determine is the height of your walls. Determine the distance from the floor to the top of your tank. Add at least four inches to this height. This will allow for the connecting pipes and insulation that you will later add. If you measure 36 inches from the floor to the top of your tank, the top of the heat storage vault should be at least 44 inches high. Subtract the thickness or the top + bottom plate (3 inches) to calculate stud height.

Stud height =(vault top height) – (3 inches). Cut all the studs needed for the frame. The quantity will probably be a few dozen. Next determine the length and width of the storage vault. The width of the platform is the length of the sidewall frames. Cut four studs this length to make the top and bottom plates of the sidewall frame. The length of the front and back walls is the length of the of the bottom platform plus seven inches. Cut four studs this length for the top and bottom plates of the front and back walls. Nail them together.

Hint: 12D nails are sufficient. Nail through the plates into studs 16 inches on center or less. Use two through the top plate and two through the bottom plate. Do not toenail through the studs into the plates.

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STEP 6 Insulating the storage vault Insulate the vault with 15-inch R13 fiberglass insulation with foil backing. It would be best if you install the insulation from inside the storage vault. If you haven’t already done so, remove the 55-gallon drums, as it will be difficult to staple insulation from the inside with those drums in there. Staple the foil flaps onto the inside frame. Now take a plastic drop cloth and staple this to the inside walls of the vault frame. A piece on the bottom platform would not hurt. The inside of the vault

will become very moist from the hot water stored in the tanks. By insulating from the inside and by lining the inside with plastic we can prevent moisture from damping out the insulation. Put the tanks back now. STEP 7 Installing sides to the heat storage vault You could finish the sides of the chamber with almost anything. Use drywall, Luan, chipboard or whatever you like.

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STEP 8. Installing sheet insulation

Slide 1-inch insulation boards between the drums and the plastic lined tank. This will increase the R-value of the walls and further retard the damping of the fiberglass insulation. STEP 9. Making the top lid

You could make a nice top lid with ¾ inch plywood.

…And there you have it: you’re very own nice neat Heat Storage Vault Now all you have to do is hook up the plumbing and run a few sensors. Mr. Sunshine will soon be working for you. Good job. Take a break. Just have your

plumbing tools with all the fittings and ¾ inch copper tubing ready for tomorrow.

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VII

HEAT EXCHANGE COILS Before you assemble heat exchange coils I wish to discuss fluid mechanics again since it is so important for the success of this project. The rationale for hooking pairs of serpentine collectors in parallel has been explained in Chapter One. This system was devised to maximize heat gain at a minimal cost by maintaining

uniform flow rate in both collectors while putting minimal stress on the circulator pump. An important concept to remember is that flow restriction should never be less than the flow restriction of the carrier pipe. Since we are using a ¾ inch carrier pipe the restriction to flow should never be less than this if possible. This is why I recommend the four collector parallel system. A two-collector system would work. A four or eight collector system would work better.

THEORY Since the heat exchange system within the heat storage vault is on the same circuit as the heat collection system we should be mindful of our flow restriction limitations. Here is a simplified schematic of a four-collector system:

Notice that the four serpentine collectors are nicely hooked in parallel, but something is missing. That’s right, the heat exchange coils are missing. Without them we won’t be able to store the heat we collect from the sun. What kind plumbing system do we want inside our heat exchange tanks?

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If we decide to employ a parallel heat exchange system like the one we are using with the serpentine collectors, 3/8-inch copper tubing coils joined in parallel could be used. Each coil would exchange heat with each tank in a uniform manner.

With this system all the heat storage tanks would always be at the same temperature. This situation is not ideal from the thermodynamic point of view that was discussed in chapter 2.

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If you like the idea of fabricating heat exchange coils by connecting coils of ½ inch flexible copper tubing in parallel you may decide to employ the next system of heat exchange. Notice that this system uses four parallel heat coils joined in series.

Parallel heat exchange coil made from two half- inch coils:

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The ½ inch parallel heat exchange coil system is acceptable from a thermodynamic point of view because the coils are joined in series to allow for storage tank temperature gradations. They are also acceptable from a fluid mechanics perspective because this parallel flow system would not significantly restrict flow rate. The problem with this coil has to do with difficulty of and cost of construction. If ¾-inch flexible tubing is not available, consider fabricating the parallel heat exchange coil using these steps:

Cut two 9-foot ½-inch coils. As you probably know, flexible copper tubing comes in a coil. Use this fact to your advantage. Do not unravel the coil to measure it. Step 1. Carefully shape these coils to fit inside 55-gallon drums. Step 2. Clean and flux all fittings and tubes about to be joined. Step 3. Place (½ to ¾ adaptors) on the ½-inch tube ends. Step 4. INLET SIDE

Connect two ends with a ¾ inch T as shown above. Insert a ¾-inch street elbow into the T. This elbow should be inside the helix pointing up. Insert a 3-foot length of ¾-inch tubing into the elbow. Solder these connections.

Step 5. OUTLET SIDE You should now be looking at a helix with three loops. Remove one of the adaptors.

Trim that end to the appropriate length and reinstall the adapter. Insert ¾- inch street elbows into the ends of the helix. Insert ¾-inch street elbows into the street elbows. Join these street elbows with two ¾-inch nipples and a ¾-inch T. The open end of the T should point toward the center of the loop. Insert a street elbow into this open end. Insert a ¾ inch copper pipe into this elbow. This outlet pipe should be pointing up like the inlet pipe.

Now solder all the outlet side connections.

Although you could fabricate heat exchange coils in this parallel manner I do not recommend it. I have a much better, much simpler coil in mind that

you can make from ¾ inch flexible copper tubing.

Thank you.Thank you.Thank you.Thank you. You are welcome.

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How flexible is ¾How flexible is ¾How flexible is ¾How flexible is ¾----inch copper tubing, and why is such inch copper tubing, and why is such inch copper tubing, and why is such inch copper tubing, and why is such large tubing necessary?large tubing necessary?large tubing necessary?large tubing necessary? ¾-inch flexible copper tubing is plenty flexible for this project. It comes pre-coiled so you’ll only need to make minor adjustments to fabricate it unless you want to knock yourself out with the ½-inch parallel coils method. You will only need one 60 ft long ¾-inch flexible copper tube per coil. Since ¾-inch has the same ID as the carrier pipe no adapters are necessary. This is the heat exchange coil that I recommend that you build. The heat gain, heat exchange schematic flow diagram looks like this:

Notice the simplicity of the heat exchange system. It is simply ¾-inch flexible copper tubing joined in series with ¾-inch rigid copper tubing. Would you like to see what one looks like? You bet.You bet.You bet.You bet. I’ll give a few instructions after the picture, though I believe its construction is so easy that you probably won’t need any step-by-step instructions.

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3/4–INCH SINGLE TUBE HEAT EXCHANGE COIL ASSEMBLY

The coil diameter should be about 2 inches less than the inside diameter of your heat storage drum. For a two-foot diameter drum you will need about 60 feet of ¾-inch tubing. The length of the tube determines the heat exchange rate. STEP 1. Shape the entire 60 ft. of copper tubing into a neat helix. STEP 2. Clean and flux two ¾-inch elbows and one ¾-inch street elbow.

STEP 3. Clean and flux the bottom end of the helix. STEP 4. INLET Cut, clean and flux a four-foot ¾-inch ridged copper tube. Insert this tube into a street elbow. Insert this street elbow into a regular elbow. Insert the other end of this elbow into the bottom end of the helix. Solder these fittings all at once so that they look like the picture. STEP 5. OUTLET Cut, clean and flux a three-foot ¾-inch ridged copper tube. Insert this tube into a clean, fluxed elbow. Insert the other end of the elbow into the top end of the helix. Solder these connections as depicted in the photograph.

Congratulations! You have just built a heat input, heat exchange coil. You will need to trim the ends of the ridged copper tubing to fit connecting plumbing. The heat extraction, heat exchange coils are built in the same manner except that the length of the ridged copper-connector tubes are shorter.

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After you have completed the construction of four heat input coils and four heat extraction coils you can solder them in place. Remove the inner lid boards from inside the heat exchange vault and place the heat input coils (the ones with the longest ridged copper input and output lines) into the heat storage drums. After placing one coil in each drum look down into each drum. You should see something like this looking back at you.

If you don’t see something like this when you look down into the drum you are doing something wrong and you should e-mail me. If you do see something like this then all systems are go and you may commence with the soldering. A three-tank heat exchange hook up would look like this:

The actual heat input and heat extraction coils would be more compressed and contain more loops. Heat transfer rate is determined by the surface area of the heat transfer coils. A ¾ inch ID tube 60 ft. long has a surface area of about 15 square feet so three coils would have a heat exchange surface area of 45 square feet. Plans for an experimental heat storage vault can be found at the back of the book if you decide to do some experimenting.

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After completing the hookup of the heat input coils, install the heat extraction coils above them. Remember these coils are flexible so if the heat input inlet tubes bump into the outlet tubes of the heat extraction coils don’t shoot yourself. Just bend a little, and bend the coils while you’re at it. The ¾-inch ridged tubing used to connect the heat exchange coils should rest upon and be flush with the rims of the heat storage tanks. Try not to set the tank varnish on fire when you solder. Prop the coils up a bit to make the soldering easy. You may want to cover the soldering

area with aluminum foil.

Making and installing the inner lid

The inner lid should be made of a substance that will not degrade in the presence of hot water such as ridged plastic or cement board. It should have a snug fit, and should look something like this when all the notches are cut out and the heat exchange coils are put into position.

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The ¾-inch ridged copper tubing that connects the coils together should not rest on the metal tank. After the inner lid is placed on top of the tanks, slide 1x4s under the connecting tubing to get the copper off the tank. The 1x4s also provide support for the heat extraction coils.

The top of the inner lid of the heat storage vault should now look like this. The inlet and outlet tubes need to be trimmed so that the ends of these tubes are about two inches below the bottom of the 2X4 top plate of the heat storage vault. Next drill four 1½ holes in the sides of the heat storage vault to accommodate the right angle connections you are about to make with the inlet and outlet tubes.

Clean the ends of the inlet and outlet tubes. Clean and flux four ¾-inch elbows. Cut and clean 4 one-foot pieces of ¾-inch ridged copper tubing. Insert one tube into each of the four elbows. Push the tube end of this assembly through one of the holes that you drilled. Push this tube from the inside of the vault. Insert the end with the elbow on it into an inlet or outlet tube. Solder the elbow in place so that the end of this assembly is now on the outside of the heat storage vault.

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The finished heat storage vault should look like this. Notice the two copper tubes protruding from the side of the vault. The tube on the left is for the ground water input. It connects to the heat extraction coils with short stems that should be positioned near the top of the 55-gallon drums.

The tube on the right comes from the heat release coils. This tube carries collector fluid. A network of pipes will connect this collector fluid output and join it with the circulator pump to return collector fluid to the collector input junction.

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VIII CIRCULATOR AND VAULT PLUMBING

PREPARE A MOUNTING PLATFORM FOR THE PUMP The pipes connecting the solar circulator pump must be secured onto a stable surface with pipe straps. The outside of the heat storage vault provides an excellent

mounting surface for the pump. Secure a 2X4 into the top and bottom sill plates of the heat storage vault with four 3-inch drywall screws. Position one 2X4 six inches from the top of the tank and the other six inches from the bottom of the tank.

Now you have something to mount the circulator pump and other plumbing hardware to. A cartoon version of the plumbing on the outside of the storage vault would look like the picture on the following page.

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OVERVIEW OF CIRCULATOR AND VAULT PLUMBING

That’s the basic hook-up at the heat storage vault end except for collector fluid inlet. This junction is where the carrier pipe comes from the collector and enters the heat storage vault. We need to add a check valve and a shut off ball valve with vent like this:

The check valve must be mounted horizontally and open towards the storage vault to work properly. This valve blocks the flow of residual cold water inside the collector fluid carrier pipe. The shut off valve with vent is used to drain the collector fluid. Be sure the vent is on the collector side of the pipe. To drain the collector fluid, open the drain down spigot, shut off the drain down valve and open the drain down vent. This vent allows air to replace collector fluid in the carrier pipe. Once the flow stops you open the drain down valve to drain the remaining fluid inside the heat exchange tubes.

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DETAILED VIEW OF CIRCULATOR AND VAULT PLUMBING: Note: Shut-off valve B has a vent.

They say a picture is worth a thousand words. You should be able to assemble the circulator system from this picture.

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ASSEMBLY Mount the pump, fill/drain spigot, purge valve spigot, shut-off A, shut-off B(with

vent), dielectric connectors and ¾ copper pipe as demonstrated on the previous page. Notice the collector fluid return line on the right of the picture. It connects to a shut off valve with the vent on the right side of the valve. The position of the vent is very important. When the collector pipes are filled with water the shut off valve should be closed and the vent should be opened. This will allow trapped air to escape from the collector pipe system. After all the air is purged from the system the vent is closed and the shut off valve is opened. Shut-off B also has a vent on the collector side of the valve to let air into the carrier pipes when draining the system. The fill/drain spigot is used to fill and drain the collector fluid from the system. Dielectric unions are used to connect the copper pipes of the collector fluid system

with the circulator pump. They are used to isolate copper from iron and prevent a chemical reaction that causes the cast iron pump to rust. The pump may come with dielectric unions. If not be sure to isolate it with dielectric unions. The expansion tank should be located a few feet above the top of the heat storage vault on the collector return pipe. Let it hang down. The expansion tank helps to moderate pressure inside the carrier pipes of the hot water system. You might want to install a bleeder valve at this junction to collect and get rid of trapped air. Trapped air will interfere with pumps ability to circulate. A fill valve is also a good investment. One of the important functions of a fill valve is to maintain a constant pressure within the circulator system.

I strongly recommend that you study a standard base hot water heating system before attempting to build a solar hot water circulator system. If you feel unsure about any aspect of this system seek the advice of an experienced plumber. Once the circulator system is complete all you have to do is replace the ground water connection of your fossil fuel heater with heat output from your storage tank. This will complete the circulator pump end of the plumbing. BUT before doing this you must complete the collector plumbing.

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IX

COLLECTOR PLUMBING

OVERVIEW The four-collector system pictured below is simplified to give a general overview of the collector plumbing connections. The main junction for the collector output is depicted as a ¾-inch cross. This cross is rare and expensive so you will probably make due with a few T’s. That funny looking thing on top represents a pressure relief valve. If there is a power outage on a hot summer day or the circulator pump does not go on when it should the collectors may overheat. The pressure relief valve will vent steam if the circulator pump stops. Details of the main collector output junction are on the following page.

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Be sure to have the ½ inch union T assembly ready before climbing on the roof to begin the collector plumbing.

Half inch union T assembly consists of one ½ inch T connected to two ½ inch union fittings and a six inch piece of copper tubing. This six-inch piece will later

be trimmed and connected to a collector main junction. You will need four of these assemblies for a four-collector system. The 3/8-inch copper tubing of the collectors is terminated with ½ inch unions. These unions will be attached to the union T assembly These assemblies will be fitted with elbows and connected to main input and output junctions.

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MAIN OUTPUT JUNCTION The main junction of the collector output consists of a pressure relief valve, ¾ pipe to sweat adaptor, one standard ¾-inch T, one ¾ X ½ X ½ T, a ¾ street elbow, ¾ copper tubing and ½ copper tubing. Additional plumbing is included to clarify union connections to the collectors.

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MAIN INPUT JUNCTION

The main collector input junction consists of a ¾ X ½ X ½ T

The proportional sizes of collectors and copper tubes are distorted to clarify the plumbing connections. The actual length of the ½ inch copper tube connecting the input junction T with the elbow is about four feet. The tube length between the elbow and the union junction T would be about four inches. You will need to adjust the length of these tubes for your particular installation.

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X

THE SENSOR SYSTEM

A sensor system is one way to make your solar hot water system work automatically. Sensors compare collector temperature with storage vault temperature. If the collector temperature is higher than the storage vault temperature the sensor relay turns on the circulator pump. You may adjust the temperature difference sensitivity. A 10 degree F difference in temperature is a

good setting. If you make the adjustment too sensitive the pump will turn on and off without accomplishing very much. Place a collector sensor close to the collector output. Bind the sensor tightly to the copper tube with a hose clamp. Connect a second sensor to a heat exchange tube junction. The best connection will depend on your style of hot water usage. You can always switch it later. You could instead install a P/V driven pump.

Now that the sensors are in place you’ll need to hook up the sensor relay to the circulator pump. Don’t plug it in yet. We need to fill the system and check for leaks before we turn on the pump.

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XI FILLING AND DRAINING THE

COLLECTOR SYSTEM

FILLING THE COLLECTOR SYSTEM Fill your solar hot water system with a garden hose from a ground water spigot. You may wish to install a basement ground water spigot or simply use your outside garden hose to fill the collector system. You’ll need a female-to-female connector.

A washing machine input hose will do fine. ONE: Hook the hose onto the fill/drain spigot. TWO: Close shut off valve A. THREE: Open shut off valve B. FOUR: Open purge valve. FIVE: Let water flow through the system until all the air is purged. SIX: Close purge valve. SEVEN: Close shut off valve B. EIGHT: Purge the last bit of air from the line. NINE: Shut off both spigots, disconnect the hose and open valve B. Now you can plug the sensor relay into the circulator pump and try out the system.

If the sun is shining you should feel heat in less than one minute. If everything looks good you can fill the heat storage vault tanks with water and batten down the storage vault hatch. INSULATION: Don’t forget to place solid insulation on top of the inner lid of the storage vault. You also need to put insulation on all the collector carrier pipes. Don’t be cheap with the insulation; a good insulation job will pay for itself in a very short time.

DRAINING THE COLLECTOR SYSTEM If there is no danger of the pipes freezing give your system a week or so to break in before draining it down and adding antifreeze. Measure the amount of water that you drain from the system. Use this measurement to calculate the amount of antifreeze to add.

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DRAINING THE CARRIER PIPES: ONE: Close the drain down valve. TWO: Open the fill/drain spigot. THREE: Open the drain-down-valve vent to let air into the collectors. FOUR: Let all the water drain from the collectors. FIVE: Cap the drain down valve vent SIX: Open the drain down valve. SEVEN: Let all the fluid drain from the system

ADDING ANTIFREEZE: Calculate the amount of antifreeze necessary for your system from the amount of water drained in the drain down process. Now hook up the garden hose and fill the collector system with water using the method described on page 75. Shut off the water supply when the system is full. Don’t close the fill/ drain spigot yet. Have a friend stationed by the supply spigot. (not the fill/drain spigot) Have your friend bleed water from the system at this junction. He/she could set up a bleeder valve at this junction or just loosen the hose connection enough to let out a little water at a time on your signal.

You’ll need to set up some kind of communication between the location of the collectors and the location of the heat storage vault plumbing. Get your butt up on the roof and unscrew the pressure relief valve from the main output junction (page 72). You should know how much antifreeze your system needs if you measured the volume of water drained from the system as on page 74. This is the amount of antifreeze you should have with you on the roof. Now signal your friend to gradually bleed water from the system as you add antifreeze to the main output junction. Do this carefully so that no air is trapped in the carrier

pipes. When you have added all the antifreeze and the fluid level is brimming at the main output junction and your friend has tightened the hose connection seal the threads of the pressure relief valve with pipe compound and screw down the pressure relief valve. Now all you have to do is have your friend turn on the water supply while you bleed any trapped air by pulling up the leaver on the pressure relief valve. Congratulations! Turn off the water supply. Close the fill/drain spigot and you’re ready to rock and roll.

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XII OTHER SOLAR APPLICATIONS

FORCED HOT AIR HEATING: This solar hot water system is not intended for home heating. However, a simple forced hot air system may be used to extract some of the heat from the heat storage vault. If you have left some space around the hot water tanks you could install a baffle system to guide forced hot air around the tanks.

Connect ductwork from a floor register on your first floor to the base of one end of the heat storage vault. The other end of the storage vault may then be connected to another floor register with ductwork. Install a fan just under one of these floor registers to force cold floor air down into the storage vault. Hot air should then enter into the first floor from the other register. BASEBOARD HEATING: An alternative to forced hot air is conventional baseboard heating. You’ll need to insert additional heat extraction coils into the heat storage vault tanks and provide an additional thermostatically controlled circulator pump. ELECTRICITY: Electricity may be produced from storage vault heat with a gas-propelled engine. Such engines do exist, but as yet they are not very practical; perhaps you will design one that is cost effective.

The future looks bright for solar application technology. Our non-renewable energy resources are becoming more rare and more expensive every day. The need to burn the fluid remains of ancestors to stay warm is no longer valid. It’s time to step out of the cave into the light of day and reestablish our life link with our sun.

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GLOSSARY

Absorber Plate: a heat conductive metallic plate capable of converting

light energy into heat energy

Active Solar: pertaining to systems that have mechanical devices such

as a fans or pumps to transport heat

Adaptor: a plumbing fitting used to join different size pipes

Angle Iron: a long iron strip with a right angle bend

Batch Heater: a tiny solar greenhouse used to heat a tank of water

Carrier Pipes: pipes used to transport fluid

Collector Fluid: a mix of water and antifreeze circulated throughout the

collector system

Collector System: a network of carrier pipes, collectors, heat release coils

and circulator pump

Drain Valve: a ball valve used to drain a network of pipes

Elbow: a plumbing fitting used to join pipes at a right angle

Expansion Tank: a tank used to moderate pressure differences inside a

network of pipes

Fill Valve: a ball valve used to fill the collectors and the carrier pipes

Fill/Drain Spigot: spigot used to fill or drain the collector system

Fluid Mechanics: study of fluid movement

Groove: that indentation made by a steel rod into absorber plate

used to hold the serpentine carrier tube.

Ground water: well water, city water or town water

Heat: product of temperature and mass

Heat Exchange Coil: a helix of copper tubing used to transport heat

from or to the carrier fluid

Heat Extraction Coil: a heat exchange coil used to preheat ground water

Heat Release Coil: a heat exchange coil used to add heat to the water

inside the storage vault tanks

Kalwall Glazing: a fiberglass reinforced plastic specially designed for solar

glazing applications

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Passive Solar: pertaining to a system that utilizes the heat from the sun

without a mechanical interface

Pounding Jig: a platform used to make the absorber plate

Pressure Relief Valve: a plumbing device that allows excess pressure to

escape from inside a plumbing system

Sensor Relay: a switch activated when sensors detect temperature

difference

Sensor System: a network of heat sensors and a relay used to control the

on/off time of a circulator pump

Slot: the ½ inch space on the pounding jig used to make the

absorber plate groove

Solar Sensor: a device used to measure temperature differences

between collectors and storage tanks

Solar Collector: a device used to harvest heat from the sun

Solar Glazing: a substance that allows visible and ultraviolet light

through while blocking infrared or heat

Stabilizing Board: a board used to hold the aluminum flashing in place

while making grooves in the absorber plate

Street Elbow: a plumbing fitting used to make a tight right angle female

to male connection

T: a plumbing fitting used to join three pipes

Temperature: the average kinetic movement of molecules

Thermodynamics: the study of heat

Tube-Bending Jig: a device used to facilitate the bending of a tube

Union: a plumbing fitting used to temporarily join two pipes

Union T assembly: a special assembly used to join serpentine

collectors at both the input and output junction.

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Hi Thank's for taking the time to read about my solar hot water system. I am presently a home improvement contractor concerned about the high cost of energy and the dwindling supply of nonrenewable resources. Fossil fuels are much too precious to use for heating water. Heating water is just one of

the many things that the sun does best.

Back in 1980 I started the Adirondack Solar Association and helped organize solar

meetings, tours, workshops and sunspace constructions while teaching general science in high school. Full time employment in the field of solar energy technology would be nice; I’m still hoping. Perhaps someday we’ll all be employed in making better use of the boundless, free energy from sunlight.

If any solar thermal concepts from this book are still unclear to you don’t hesitate with e-mail. Send e-mail to canivan@optonline.net.

Or post a message in the forum at: www.JC-SolarHomes.com

80

g{x XÇw

Actually it’s more like the beginning. The field of solar thermal energy

is a new frontier with new possibilities for a new less dependent, more

earth friendly way of living. Cost effective solar applications that make

practical use of the sun’s boundless energy can help us find our way

back to our roots. As the price of oil increases products associated

with oil energy will rise. The cost of transportation, heating, electrical

power and food will become a major concern. I predict that small local

farms will be more valuable in the future and those small businesses

that encourage energy independence will be in a position to flourish. If

you understand how sun energy works you know the tools and materials

to build a better world do not depend on big business and big

government. They depend on natural resources and our ability to use

these resources wisely. Opportunity knocks.

Will we answer the door?

81

Experimental Non Pressurized Heat Storage Vault with Built in Tanks

You’re probably sick of reading about heat storage vaults by now, but I’ve got one more for you that will make the others look silly by comparison. As

far as I know this tank has never been built by mortal man or mortal woman

for that matter. This is a cutting edge design that I haven’t had time to test

yet, but I’m confident that it will work. Perhaps you’ll be the first to build it. If you do, let me know if it’s as good as I think. It should be less expensive,

more efficient and easier to build than any of the other designs. No special

“hard to find” tanks are needed. You’ll build your own tanks from commonly

available construction materials and “… do more with less”.

This project is similar to the last one except that stand alone tanks will be

unnecessary. The idea came to me one day when I became frustrated with

the task of finding a good supply of 55 gallon drums. I see them chained to

posts in parks. I know they wait patiently on the edges of concession stands and stand proud and tall at beaches, restraints and parking lots across the

nation, but when it comes time to purchase a 55 gallon drum at K mart or

Home Depot the clerks just shake their heads and throw up their hands in

confusion. People are always giving them to me but I never know where to get them. Anyhow I got crazy one day and said to myself who needs those

rusty old tanks anyhow. That’s when I sat down and designed this simple

vault made from 2x6s, 2x4s plywood, polystyrene foam, siding insulation,

copper tubes, cement and a sheet of plastic. Non-pressurized tanks need not be made of steel they only need to hold water.

Any water proof container can do that. Swimming pool inserts pressed tight

against pool walls provide an excellent seal against the inevitable leaks that

occur when the earth shifts and walls develop cracks. These inserts would

make an excellent lining for a heat storage vault, but even these hard to get custom linings are unnecessary. A simple inexpensive polyethylene drop

cloth is all you need to waterproof the inside of a vault.

Why not? What do you think?

82

The base of a 14 foot long vault might be framed with 2x6 PT lumber.

Look familiar?

83

Heat Storage Vault Instructions

First construct a base frame like the one on the previous page.

Pack it with solid insulation before sheathing it with plywood.

Next secure a 2x4 frame to this plywood as shown below.

So far so

good

A network of copper tubes (coated with polyurethane) are then

placed in the hollow of the frame and cemented into position to

provide a heat input exchange area. Polyurethane protects the

copper from the corrosive effect of the cement.

84

VAULT FRAME WITH POLYSTYRENE BARRIERS

I’ll leave the framing of the vault up to you. If you’re not sure

how to frame contact me or find a carpenter.

canivan@optonline.net

When you’re done don’t forget to insulate and sheathe the frame,

but don’t break for lunch yet. You need to glue 2” strips of

isocynate insulation to the inside of the vault. These strips should

have a three inch gaps between them. These gaps will later be

used to support 3” polystyrene inserts that form the tank petitions. The edges of the insulation should be smoothed,

plastered and sanded to avoid tearing the plastic sheet when the

3” polystyrene inserts are installed.

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After you’re satisfied that the interior of the vault is as smooth as

a baby’s you know what, carefully insert and glue a sheet of

polyethylene plastic onto the vault walls. Use glue that remains

soft and flexible like rubber cement. Press the plastic into the

grooves. Now comes the hard part. Slide the polystyrene foam barriers between the 3” grooves without tearing the plastic. Sand

the edges of the solid insulation first to avoid problems.

THE OPEN VAULT

If you did a good job, the open vault should look something like

this with some excess plastic hanging out over the sides. The number of chambers is up to you, but you should have at least

two. Vaults like this could be hooked in series. If you decide that

additional heat storage is necessary it’s an easy matter to build

and install additional vaults.

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The heat out or heat

extraction tubes is

where heat from the

hottest area of the storage vault is

extracted into the

radiant heating system

or domestic hot water

system. Notice that the

water is heated in

stages. Each chamber

preheats the water

before it enters the

next chamber.

CROSS SUPPORTS

The cross supports not

only prevent the

chamber from collapsing

under the weight of all

that water, but they also

hold the polystyrene

foam barriers in place. Without these cross

supports the foam

barriers would be

displaced by the water

and pop out of the

chamber.

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TOP ENCLOSURE

Fill the chambers with water and than insulate the top of the

vault with solid foam insulation before screwing down the lid. You could let the foam insulation float if you like but be sure to cover

this insulation with additional plastic to prevent a possible

moisture problem in the basement.

Best of luck with this, and all your solar thermal energy projects. If you need help you may contact me: canivan@optonline.net

88

Greetings Sun Person,

How to Build a Solar Hot Water System should get you off to a good

start with a practical solar thermal energy project. If you follow the

instructions you should soon be saving money with free energy from

the sun. Suggestions are welcome and clarification is provided at:

“Sun Heat University” an online, interactive school located in the wonderful world of www.JC-Solarhomes.com

Other great books available from Sunny Future Press include:

Solar Thermal Energy is a comprehensive guide into the practical world of solar applications. This book/CD-ROM show

combination will bring you one step closer to the sun.

Energy Independent Housing will set you free from fossil fuel corporations forever. Imagine saving fuel oil and electricity, while

reversing the process of land and air pollution.

Solar Heating Projects provides the reader with a step by step guide to dozens of solar heating projects designed

to save energy and save money. These projects include:

Solar Concentrators, Hot Boxes, Window Boxes, Trombe

Walls, Solar Greenhouses, Batch Heaters, Thermo Siphoning

Systems, Solar Collector Construction, Collector Mounting,

Five Heat Storage Systems, Collector Plumbing, Solar

Thermal Roof Theory, Solar Thermal Roof Construction,

Energy Independence, Solar Cell Theory, Cu/CuO solar cell

construction as well as some solar thermal engine theory.

May the sun forever shine upon you… ]É{Ç VtÇ|ätÇ]É{Ç VtÇ|ätÇ]É{Ç VtÇ|ätÇ]É{Ç VtÇ|ätÇ