ENERGY FROM THE SUN SOLAR THERMAL TECHNOLOGIES …cactusmooneducation.com/.../uploads/2018/10/sth01pp-solarthermal… · Solar Parabolic Trough • In a parabolic trough system, long

__________________________

© Cactus Moon Education, LLC. Cactus Moon

Education, LLC.

CACTUS MOON

EDUCATION, LLC www.cactusmooneducation.com

ENERGY FROM THE SUN

SOLAR THERMAL

TECHNOLOGIES

EDUCATION MODULE (sth01pp)

http://www.cactusmooneducation.com/

__________________________


Education, LLC.

INDEX

• Slide 1 Front Sheet

• Slide 2 Index

• Slide 3 Solar Thermal Technologies

• Slide 4 – 6 Solar Power Tower

• Slide 7 – 8 Solar Parabolic Trough

• Slide 9 - 10 Dish Stirling

• Slide 11 - 12 Solar Chimney

• Slide 13 - 16 Solar Heating and Cooling

• Slide 17 - 20 Solar Water Heating

__________________________


Education, LLC.

Solar Thermal Technologies

• Solar Thermal technologies use the heat from the sun as

a source of energy to produce electricity, provide hot

water or provide space heating and cooling.

• Solar collectors harvest the sun’s energy and use it to

heat a “transfer” liquid.

• The “transfer” liquid takes the solar energy from the solar

collector field to the operating system where the heat

energy is used.

__________________________


Education, LLC.

Solar Power Tower

• In a power tower system a field of computer controlled

mirrors (heliostats) concentrates the sun’s energy onto a

boiler or “receiver” on the top of a large tower.

• The heat transfer liquid is pumped up to the receiver

where it is heated by the concentrated solar energy.

• The hot liquid is then used to boil water and make steam

which is used to power a turbine/generator and make

electricity

• The heat transfer liquid can be mineral oil or a mixture

of molten sodium and potassium nitrate salts.

__________________________


Education, LLC.

Solar Power Tower – using mineral oil as the heat transfer liquid

The oil is heated as it

passes through the

receiver

3

3

The sun’s energy

is concentrated

onto the receiver

by the heliostats

2

2

Cold oil is pumped up

the tower into the

receiver

1

1

The hot oil is used

to boil water in the

steam generator

4

4

The steam is used

to power the

turbine/generator

5

5

The oil is re-

pumped up the

tower to be heated

again

6

6

__________________________


Education, LLC.

Solar Power Tower – using molten salt as the heat transfer liquid

By making more hot salt than is needed to keep the turbine/generator running during the

sunshine hours, the salt in the hot salt storage tank can be used to power the turbine/generator

after the sun has set. This is an example of thermal energy storage.

Cold (500º F) salt is

pumped from the cold

salt storage tank up the

tower and into the

receiver

1

1

The sun’s energy is

concentrated onto

the receiver by the

heliostats

2

2

The salt mixture is

heated to over 1,000º

F as it passes

through the receiver

3

3

The hot (1,000º F)

salt mixture is stored

in the hot salt

storage tank

4 4

Hot salt is drawn as

needed to boil water

in the steam

generator

5

5

The salt mixture is

pumped to the cold

salt storage tank ready

to be pumped back up

the tower to be heated

again

7

7

The steam is used to

power the

turbine/generator

6

6

__________________________


Education, LLC.

Solar Parabolic Trough

• In a parabolic trough system, long rows of curved mirrors

concentrate the sun’s energy onto pipes carrying the

heat transfer liquid.

• As the liquid makes its way through the solar collector

field it is heated.

• When the liquid leaves the solar collector field it is hot

enough to boil water and make steam.

• The steam is used to power a turbine/generator and

make electricity.

__________________________


Education, LLC.

Solar Parabolic Trough The solar

collection field is

made up of long

mirrors shaped in

the form of a

parabola with

pipes running

along the focal

line of the

parabolas

1

1

The steam is used

to power a

turbine/generator

5

5

The oil is pumped

back into the solar

field to be heated

again

6 6

The mirrors

concentrate

the sun’s

energy onto

the pipes

2

2

Oil is pumped

through the pipes

and is heated as it

runs through the

solar field

3

3

The hot oil is

used to boil

water in a steam

generator

4

4

__________________________


Education, LLC.

Dish Stirling Solar Heat Engine

• Instead of using the heat from the sun to heat a liquid, the captured heat can be used to power a “heat-engine”

• The most common heat engine used in solar applications is the Stirling Engine.

• The engine is a completely sealed unit and contains a number of cylinders containing pistons which are connected to a crankshaft which is, in turn, connected to an electrical generator.

• As the pistons are made to travel up and down they turn the crankshaft and generator and produce electricity.

• The pistons are powered by the expansion of a gas on top of them. Heat causes the gas to expand and drive the piston down its cylinder and so turn the generator.

__________________________


Education, LLC.

The gas expands and

pushes a piston down a

cylinder. 3 3

The piston is connected

to a crank shaft which

turns and drives an

electric generator.

4

4

The expanded

gas is cooled and

allows the piston

to return to the

top of the

cylinder. 5

5

A large, concave, parabolic

mirror concentrates the sun’s

energy onto a thermal receiver”

located at the focus of the

mirror.

1

1

The thermal receiver

directs the heat energy into

the Stirling heat engine

where it heats a gas inside

the engine.

2

2

2

Dish Stirling Solar Heat Engine

__________________________


Education, LLC.

Solar Chimney

• A solar chimney uses the fact that hot air rises.

• The energy from the sun is used to heat air and the hot air is directed into and up a centrally located chimney.

• The moving air mass can be used to power wind turbines placed in the path of the moving air.

• “Wind” speeds of 40 mph can be created within a solar chimney system

• The wind turbines generate electricity

__________________________


Education, LLC.

Solar Chimney

A large “greenhouse” captures the

solar energy and heats up the air

inside the greenhouse

1

1

3

3

The moving hot air can

be used to spin wind

turbines located at the

base of the chimney

2

2 The greenhouse is designed in

Such a way that the hot air can

move into the center of the

greenhouse and up a large

centrally located chimney.

4

4 The wind turbines

generate electricity

__________________________


Education, LLC.

Solar Heating and Cooling -1

• Solar energy can be “captured” and used to provide space heating

in the Winter and space cooling in the Summer.

• The solar collector field is made up from long rows of curved mirrors

which concentrate the sun’s energy onto pipes carrying a heat

transfer liquid.

• The transfer liquid is heated as it makes its way through the solar

collector field and transfers the heat to water in a large hot water

storage tank.

• Hot water from the storage tank can be used to provide space heat

in the Winter months and can be used as the heat source for an

absorption chiller to provide space cooling in the

Summer months.

__________________________


Education, LLC.

The solar

collection field is

made up of long

mirrors shaped in

the form of a

parabola with

pipes running

along the focal line

of the parabolas

1 1

The mirrors

concentrate the

sun’s energy onto

the pipes

2

2

A mixture of ethylene

glycol (anti-freeze)

and water is pumped

through the pipes

and is heated as it

runs through the

solar field

3

3

The hot glycol mixture is

used to heat up water

contained in a hot water

storage tank

4

4

The glycol mixture is returned to

the solar field to be heated again

5

5

Solar Heating and Cooling -1

In the Winter, the

hot water in the

storage tank can

be used to heat up

water circulating in

the HVAC system

heating loop.

6

6

In the Summer, the hot water in the storage tank

can be used as the heat source to power an

absorption chiller. The absorption chiller is used

to cool the water circulating in the HVAC system

cooling loop

7

7

__________________________


Education, LLC.

Solar Heating and Cooling - 2

• For small solar heating and cooling systems (less than 20 tons of

cooling) a solar collector field made of “flat plate” collectors can be

used.

• The flat plate collectors are made of copper pipes that absorb the

heat from the sun when the sun shines on them.

• A heat transfer liquid – typically a water and ethylene glycol

(antifreeze) mixture – is used to transfer heat from the solar collector

field to a hot water storage tank.

• Hot water from the storage tank can be used to provide space heat

in the Winter months and can be used as the heat source for an

absorption chiller to provide space cooling in the

Summer months.

__________________________


Education, LLC.

The solar

collection system

is made up of flat-

plate solar water

heaters (solar

collectors)

containing copper

pipes

1

1

The pipes are

painted black and

absorb heat from

the sun when the

sun shines on

them

2

2

Solar Heating and Cooling - 2

In the Winter, the

hot water in the

storage tank can

be used to heat up

water circulating in

the HVAC system

heating loop.

6 6

In the Summer, the hot water in the storage tank

can be used as the heat source to power an

absorption chiller. The absorption chiller is used

to cool the water circulating in the HVAC system

cooling loop

7

7

A mixture of

ethylene glycol

(anti-freeze) and

water is heated as

it is pumped

through the copper

pipes

3

3

The hot glycol mixture is

used to heat up water

contained in a hot water

storage tank

4

4

The glycol mixture is

returned to the solar

field to be heated again

5

5

__________________________


Education, LLC.

Solar Water Heating - Residential

• One of the simplest uses of solar energy is to heat water.

• Just about every home in the USA uses hot water for bathing, laundry etc and solar energy can provide a supply of hot water for these and other activities.

• For small, residential, solar water heating systems flat plate solar collectors can be used.

• The flat plate collectors are made of copper pipes that absorb the heat from the sun when the sun shines on them.

• A heat transfer liquid – typically water or a water and ethylene glycol (antifreeze) mixture – is used to transfer heat from the solar collector field to a hot water storage tank.

• Hot water from the storage tank can then be used in the residence.

__________________________


Education, LLC.

Solar Water Heating - Residential

A flat plate solar

collector contains

copper pipes that are

painted black

1

1

The hot water in the tank

is available to be used in

the residence

4

4

The heated water flows

through a “heat

exchanger” in the hot

water storage tank and

heats the water in the tank

3

3

Water is pumped

through the pipes and

is heated when the sun

shines on the collector

2

2

__________________________


Education, LLC.

Solar Water Heating - Commercial

• Larger solar water heating systems for commercial or industrial use typically use a solar collector field made up from long rows of curved mirrors which concentrate the sun’s energy onto pipes carrying a heat transfer liquid.

• The heat transfer liquid is heated as it makes its way through the solar collector field and transfers the heat to water in a large hot water storage tank.

• Hot water from the storage tank can be used for many commercial purposes such as laundries, kitchens, health club showers.

__________________________


Education, LLC.

Solar Water Heating - Commercial

The solar collection field is

made up of long mirrors

shaped in the form of a

parabola with pipes running

along the focal line of the

parabolas. The mirrors

concentrate the sun’s

energy onto the pipes

1 1

The hot water in the

tank is available to

be used for laundry,

showers or other

applications

4

4 2

A mixture of ethylene glycol

(anti-freeze) and water is

pumped through the pipes and

is heated as runs through the

solar field

2

The hot glycol mixture

is used to heat up

water contained in

water storage tank

3

3

Documents

ENERGY FROM THE SUN SOLAR THERMAL TECHNOLOGIES …cactusmooneducation.com/.../uploads/2018/10/sth01pp-solarthermal… · Solar Parabolic Trough • In a parabolic trough system, long