Energy Management Opportunitiesin

Heating, Ventilation and Air Conditioning (HVAC)

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Your panelists

– Benefits, Technologies & Services: Mike Carter and Mark Farrell, Energy Engineers

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Why is HVAC important?

– Productivity– Comfort– Expense

Source: www.bcs.org

Source: www.doe.gov

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Contents

– Basics– Cooling

Chillers Packaged Rooftops Packaged Terminal Air Conditioners (PTACs) Geothermal Heat Pumps

– Heating Electric/Electrode Boilers Space Heaters

– Accessories– Energy-Savings Tips– Business Solutions Toolkit– Rebates/Incentives

Source: NREL

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HVAC basics

– Power versus Energy Kilowatt (kW), or demand, is a measure of

power, similar to the speedometer of your car that records the rate at which miles are traveled.

• A bigger engine is required to travel at a faster rate.

Kilowatt-hour (kWh) is a measure of energyconsumption, similar to the odometer on your car which measures the miles traveled.

Energy cost = energy consumption x unit cost = kWh x $/kWh = kW x hrs x $/kWh

• A 50-ton chiller with a 0.8 kW/ton efficiency costs about $11,200 annually when operating 2,800 load hours (40 kW x 2,800 hr x $0.10/kWh national average)

Source: stock.xchng

Source: Commonwealth of Kentucky

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HVAC basics

– Temperature Dry bulb

• Normal thermometer Wet bulb

• Bulb wrapped in cloth—called a sock—that is kept wet with water via wicking.

Dew point• Temperature to which air

must be cooled for the water vapor component to reach saturation and condense into water.

Dry Bulb Temperature

(°F)

Relative Humidity

Wet Bulb Temperature

(°F)

Dew Point (°F)

70 100% 70 70

60% 61 56

30% 53 38

55 100% 55 55

60% 48 42

40% 45 37

30% Not Sustainable Ice

Source: Microsoft Encarta

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HVAC basics

– Relative Humidity Relative humidity compares water vapor in the air with the concentration of water vapor

that the atmosphere could hold (if the atmosphere were at saturation). Usually expressed as a percentage. When the actual concentration of water vapor in air is equal to the water vapor

concentration at saturation, the relative humidity is 100%.• There is one gallon of water in a 20' x 50' x 8' room at 68ºF and 100% RH• There is only 0.1 teaspoon of water per cubic foot of air at 68ºF and 100% RH

Operation at 78°F / 40% RH provides the same level of occupant comfort as 74°F / 50% RH does due to evaporative cooling.

In this example, specific (absolute) humidity does not change until the dew point is reached.

4C40F

100%RelativeHumidity

H2O

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HVAC basics

– Degree Days Degree day calculations provide a rough estimate of the heating and

cooling load for a particular location. Degree days are based on the difference between a day's average daily

temperature and the "balance point" temperature of 65°F (or 18°C). • Cooling Degree Day (CDD) = (Average Temperature – 65°F) x

days/month• Heating Degree Days (HDD) = (65°F – Average Temperature) x

days/month• Location dependent and data available

from National Climate Data Center (NCDC),WeatherUnderground, and other sources.

Source: Utility Allowance

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HVAC basics

– Load Hours HVAC load hours may be calculated from degree days using

a formula which incorporates Outside Design Temperatures. • Cooling Load Hours (CLH) = CDD x 24 / (Cooling Outside Design

Temperature – 65°F)» Cooling Outside Design Temperature (ODT) is in the range of

70°F to 105°F• Heating Load Hours (HLH) = HDD x 24 / (65°F – Heating Outside

Design Temperature)» Heating Outside Design Temperature (ODT) is typically

between -12°F and 40°F.» It is necessary to reduce the heating load hours by about 40% to

match actual energy consumption.

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HVAC basics

– HVAC Load Hours

Source: Louisiana Department of Natural Resources, Technology Assessment Division

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HVAC basics

– Efficiency Ratings One ton (12,000 Btu/hr) equals 3.516 kW at 100% efficiency Coefficient of Performance (COP)

• COP = Rated Cooling Output, kBtuh / Rated electrical input, kBtuh Full Load Value (FLV)

• FLV = kW/ton• COP = 3.516 (kW/ton) / FLV efficiency rating (kW/ton)

Energy Efficiency Ratio (EER)• EER = Cooling output (Btu) / Electricity consumed (watt) • EER = 12,000 Btu per ton / FLV (watt per ton) • EER = COP x 3.413

Application Part Load Value (APLV)• Other than full load

Integrated Part Load Value (IPLV)• Weighted average of full load and part load

FLV(kW/ton)

COP EER

0.6 5.9 20

0.75 4.7 16

1.0 3.5 12

1.5 2.3 8

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HVAC basics

– Seasonal Energy Efficiency Ratio (SEER) Test conditions for determining SEER values are defined by ANSI/ARI standard 210-240-2008.

• Indoor air across the evaporator at 80ºF with 50% RH (wet) and <20% RH (dry)• Outdoor air across condenser at 82ºF with 40% RH (wet)

» Outdoor air at 95ºF and 40% RH (Test A) is used to establish capacity and EER

Four categories of air-conditioning systems are tested. ARI does not require manufacturers to report the results of dehumidification performance.

SEER = (1 - (0.5 x [1 - (EERC/EERD))/(1 - CLF)]) x EERB

EERB = Energy Efficiency Ratio determined from Test B (steady, wet)

EERC = Energy Efficiency Ratio determined from Test C (steady, dry)

EERD = Energy Efficiency Ratio determined from Test D (cyclic, dry)

CLF = Cooling Load Factor

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– Estimation of annual operating cost 300 ton chiller; FLV = 0.75 kW/ton (EER=16, COP=4.7);

$0.10/kWh; national average• Energy cost = Size (ton) x FLV (kW/ton) x CLH (hrs)

x Electric rate ($/kWh)• Energy cost = 300 ton x 0.75 kW/ton x 600 hrs x $0.10/kWh

= $13,500

5 ton heat pump; 13 SEER• Energy cost = [Size (MBtuh) x CLH (hrs)]/ SEER (Btu/watt)

x Electric rate ($/kWh)• Energy cost = [5 ton x 12 Mbtuh/ton x 600 hrs]/ 13 Btu/w

x $0.10/kWh = $275

HVAC basics

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HVAC basics

– Vapor Compression/Expansion Cycle

Source: www.makinemekanik.com

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HVAC basics

– Refrigerants Issues are depletion of the ozone layer and contribution

to global warming• Manufacturers still are allowed to produce R-22 to service

existing equipment• After 2020, cannot produce R-22, but can service existing

systemsRefrigerant ODP1 GWP2 Application

CFC-11 1.0 4,680 Centrifugal chillers

CFC-12 1.0 10,720 Chillers, refrigerators

HCFC-22 0.04 1,780 AC, chillers

HCFC-123 0.02 76 R-11 replacement

HFC-134a <0.00001 1,320 R-12 or R-22 replacement

HFC-407c <0.00001 1,700 R-22 replacement

HFC-410a <0.00001 1,890 AC

1Ozone Depletion Potential2Global Warming Potential

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HVAC basics

– Delivery Water is much denser and stores much more heat

[cooling]. A 1" (25 mm) diameter pipe containing hot/cold water can

deliver more energy than a 18" x 12" (0.45 m x 0.3 m) duct, even though the air is moving much faster in the duct than the water in the pipe.

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HVAC basics

– Indoor Air Quality ASHRAE 62.1-2007 Ventilation for Acceptable Indoor Air Quality

• “Air in which there are no known contaminants at harmful concentrations as determined by cognizant authorities and with which a substantial majority (80% or more) of the people exposed do not express dissatisfaction.”

Ventilation Rate Procedure• People Outdoor Air Rate (Rp)• Area Outdoor Air Rate (Ra)

» For instance, office areas—5 cfm/person and 0.06 cfm/ft² Indoor Air Quality (IAQ) Procedure

• Based on an analysis of contaminant sources, contaminant concentration targets, and perceived acceptability targets.

» CO2 sensors are one method • Credit is given for controls that remove contaminants, such as filters and UV light, that

can achieve concentrations equal to or lower than those achieved by the Ventilation Rate

Procedure.

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Cooling

– Chillers

Chiller Minimum Efficiency Requirements (ASHRAE 90.1-2004)

Compressor Type/CapacityFull-Load Rating,

COP (kBtu)Full-Load Rating,

FLV (kW/ton)Part-Load Ratings,

IPLV (kBtu)

Reciprocating (30-150 tons) 4.20 0.84 5.05

Screw/Scroll (<150 tons) 4.45 0.80 5.20

Screw (150-300 tons) 4.90 0.72 5.60

Screw (301-800 tons) 5.50 0.64 6.15

Centrifugal (<150 tons) 5.00 0.70 5.25

Centrifugal Chiller

Best available Full-Load FLV is 0.47-0.58 kW/ton for large (>150 ton) water-cooled chillers

Source: ORNL

Source: EERE

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– Water-cooled centrifugal chiller versus air-cooled screw chiller (20-year life) in office building Energy simulation using DOE-2.2 Calculation Core Engine Net Present Value (NPV) of total costs of ownership

Cooling

Source: Total Cost of Ownership For Air-Cooled and Water-Cooled Chiller Systems, Ramez Naguib

Cost Category100-ton 500-ton

Air Water Air Water

New York City

Initial 50% 68% 22% 42%

Energy 40% 20% 63% 45%

Maintenance 10% 12% 15% 13%

Minneapolis

Initial 72% 78% 45% 60%

Energy 16% 10% 35% 20%

Maintenance 12% 12% 20% 20%

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Cooling

– Chiller Maintenance Tips Visual check of compressor oil (darker is worse).

• Change oil on large systems once a year and clean particles from case. Take superheat and subcooling temperature readings to obtain chiller's maximum

efficiency. Install water gauges so you can see pressure drops, particularly through the evaporator.

• If tubes need cleaning and the interiors of the tubes are smooth bore, technicians can remove the sludge with bristle brushes attached to long metal rods.

Put a bypass valve on the end of the pipe run going to the chillers to get the proper water flow (overflow can cause vibration, damaging the copper tubes).

Clean water tower condensers and unclog spray nozzles, especially in the spring. Check for high vibration on a capillary line (causes leaks) and secure all vibrating lines.

Source: John C. Schaub Inc., Mt. Laurel, NJ

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Cooling / heating

– Packaged Rooftop

Image courtesy of McQuay International

Unitary Air Conditioner Minimum Efficiency RequirementsASHRAE 90.1-2004

Full-load EER (Btu/watt)

Size Range Pre-2010 As of 2010*

65-135 kBtu/hr (5-11 ton) 10.3 11.2

135-240 kBtu/hr (11-20 ton) 9.7 11.0

240-760 kBtu/hr (20-63 ton) 9.5 10.0

>760 kBtu/hr (>63 ton) 9.2 9.7

*Phase-out date for R-22 refrigerant

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Cooling / heating

– Packaged Terminal Air Conditioners (PTACs) EER of 10 to 12 available today Suppliers include Amana, Bard, Carrier, ClimateMaster,

Friedrich, GE, and SkymarkPTAC/PTHP Minimum Efficiency Requirements

ASHRAE 90.1-2001

ReplacementNew

Construction

Cooling Full-load EER (Btu/watt)

PTAC (7,000 Btuh) 9.4 11.0

PTAC (15,000 Btuh) 7.7 9.3

PTHP (7,000 Btuh) 9.3 10.8

PTHP (15,000 Btuh) 7.6 9.1

Heating Full-load COP (Kbtuh)

PTHP (7,000 Btuh) 2.7 3.0

PTHP (15,000 Btuh) 2.5 2.8

Source: www.amana-ptac.com/

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Cooling / heating

– Geothermal or Water-Source Heat Pump Takes advantage of underground temperatures that range from 45°F (7°C) to 75°F

(21°C). Roughly 30% savings compared to AC/Boiler or AC/Furnace combination Geothermal requires higher capital investment and requires a significant amount of

space Hybrid geothermal saves on first cost but operating costs are higher

Loop Depth Length/ton

Vertical 100-500' 300-400'/ton

Horizontal 5-6' 800'/ton

Pond >8' 400'/ton

Image courtesy of ECS Geothermal

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Cooling / heating

– Coil Cleaning Most commercial HVAC units have multiple coils

stacked or sandwiched together. Outdoor condenser coils lose less performance

with blockage than indoor evaporator coils.• If the evaporator airflow of a 3-ton rooftop

unit is restricted by 36%, the capacity drop is 19.4%.

» This changes the 3-ton unit to a 2.5-ton unit. • On the other hand, when the condenser coils are

56% restricted, the capacity drops only 10.9%.» Blocked condenser coils can increase condensing temperature by

8°F to 10°F resulting in a 6% to 8% increase in power consumption. You can check coil performance by measuring the air temperature drop across the coils.

• Larger temperature drops of 30ºF or higher indicate that a coil cleaning is in order. You can also measure supply-fan amperage or filter/coil pressure drop (with fresh filters)

and compare this data against last year's readings.

Image courtesy of Coil-Tech

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Heating

– Electric Boilers Available from 10 kW for the smaller units up to over 3,000 kW Often used in tandem with a gas-fired boiler in a fuel-switching strategy Replacement of an electric element bundle (13-18 year life) can range in price from $2,000 to

$2,500 for a 75 kW to 100 kW electric boiler

– Electrode Steam Boilers Operate at high voltages (12 kV or 24 kV) Submersible electrode boilers

• Rely on immersed electrodes to conduct

electricity through the boiler water

High-velocity jet electrode boilers

• In this design, the water jet (striking an

electrode plate) is the resistance element

Pros include lower installed capital cost, higher

reliability, higher efficiency (99.5% at 100% output)

and rapid response

Source: Precision Boilers

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Heating

– Space Heaters All portable electric heaters using a heating element are equally efficient

in that they essentially convert all the electricity they use into heat• Only more cost-effective than whole-house

furnaces if temperature is reduced in other rooms

Quartz "Infrared" space heaters such as SunHeat and EdenPure

• Infrared radiation does not warm you directly

Traditional infrared (picture) has the coils and lamps exposed for direct line of site radiation

Ceramic and oil-filled heaters arguably provide greater heating comfort because they retain some heat after the current is off

Source: Fostoria Industries

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Accessories

– Economizers bring in cool outside air Typical 2 to 5 year payback for economizers Required by ASHRAE 90 for >5 tons in cool/dry climates (West) and

>11 tons in cool/moist climates (Midwest), but not in warm/moist

climates (Southeast)

Four Economizer Modes

Mode Temp. (ºF) Mechanical Damper

Heating <30 On Closed

Modulated Economizer 30-55 Off Varies

Integrated Economizer 55-75 On Open

Cooling >75 On Closed

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Accessories

– Heat Recovery Ventilators Can recover about 60% to 70% of heat in exiting air

• Low grade heat for space heating and equipment expense results in long paybacks

A solution to ASHRAE 62 IAQ requirements

Source: George Retseck Illustrations

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Accessories

– Energy/Enthalpy/Desiccant Wheels Can recover about 70% to 80% of the energy in the exiting air and deliver that energy to

the incoming air.• Desiccant wheels are most cost effective in climates with extreme winters or

summers, and where fuel costs are high.

In mild climates, the cost of the additional electricity consumed by the system fans and drum motor may exceed the energy savings from not having to condition the supply air.

Source: Fläkt Woods

Source: EERE

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Accessories

– Thermal Energy Storage (TES) Thermal energy storage makes ice or chilled water during the night—shifts peak. Full Storage system shifts the entire load to off-peak hours and is driven by electric rates and

rebates. In a Partial Storage system, a much smaller chiller runs during both peak and off-peak hours with

help from stored cooling during peak hours.

• Attractive when more cooling capacity is needed or when a chiller needs to be replaced. Ice Energy (Windsor, CO) offers factory assembled modular ice making systems (Ice Bear) for small

to medium-sized commercial applications.

Image courtesy of CALMAC Manufacturing Corporation

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Accessories

– Thermal Energy Storage (TES) Ice can absorb eight times the thermal energy of

chilled water. Three up-front decisions during system design:

• How the ice is made and stored (ice on coil—internal melt, ice on coil—external melt, or encapsulated ice).

• How the ice bank is discharged.• How cold is transported to the load (slurry

systems versus brine or glycol transfer).

Image courtesy of FAFCO, Incorporated

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– Thermal Energy Storage (TES) Example: Shifting from peak to non-peak times with a

resultant 600 kW drop in peak demand (1,500 kW to 900 kW)• For example– at a demand charge of $8.00/kW, that saves

$4,800 per month. • Additional savings are possible if time-of-use rates result in a

lower $/kWh energy charge during off-peak hours. Example: A normally 400-ton chiller outputting 3,000

ton-hours per day might be replaced by a 160-ton chiller.• Produces 1,600 ton-hours during a 10-hour peak time period.• Produces 1,400 ton-hours during a 14-hour off-peak period.

Accessories

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Energy-savings tips

– Temperature Setback/Setforward Save 3% per °F per 24 hr 72°F 68°F ( 4°F) for 12 hr saves 6%

– Obtain Proper Humidity Control In the summer, decrease relative humidity (RH) to feel cool. Operation at 78°F / 40% RH provides the same level of occupant

comfort as 74°F / 50% RH does.• 74°F 78°F setforward for 24 hr saves 10% to 12%• Remove moisture with desiccant or enthalpy/heat wheel

• Relative humidity >70% with temperature > 70°F can encourage mold growth!

In the winter, opposite applies—raise RH to feel warm.• Add moisture with evaporative humidifier• Ultrasonic humidifiers require filtered water

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Energy-savings tips

– Narrow your chiller water temperature set points Typical conditions are chilled water temperature of 42°F

and condensing water temperature of 80°F to 85°F.• 2% savings per °F that chilled water temperature is raised• 5°F to 10°F increase is possible; more may cause damage and

reduce cooling capacity (ton rating) Efficiency benefits from lowering condensing water temperature are offset

by increased fan and pump operation, along with reduced cooling capacity.

• Variable Frequency Drives (VFDs) and oversizing the cooling tower can help

• The larger the system, the greater the net energy savings

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The Business Solutions Toolkit

– Reduce energy expenditures with free, online tools Energy benchmark data by business segment Efficiency recommendations by business segment Lighting, motor and other energy calculators Facility energy assessment… plus more

– Get energy answers with live Web resources “Ask an Expert” service supplies direct answers to energy questions Searchable Energy Library and News resources Monthly electronic newsletter delivered to your e-mailbox

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How to access the Toolkit

– Links found on the Rocky Mountain Power website Can access direct at rockymountainpower.net/toolkit

– Toolkit resources also are delivered to you as part of our monthly electronic newsletters

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What is in the Toolkit

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Online business tools rockymountainpower.net/toolkit

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Rocky Mountain Power FinAnswer Express

– FinAnswer Express is for commercial and industrial customers– either retrofit or new construction

– Pre-calculated incentives for HVAC equipment and high-efficiency lighting

Custom incentives may be available for other types of equipment

– Incentive process (pre-purchase agreement or post purchase application) varies by technology and project type

Please understand the process before you purchase!

– Check our website for on-line forms plus trade allies available to help

– Also check for state and federal tax incentives at dsire.org

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RMP Energy FinAnswer

– Applies to comprehensive commercial or industrial projects– either new construction or commercial retrofit* Lighting and non-lighting projects can be packaged

– Starts with an energy analysis to identify options and highest priority measures Commissioning is required for most measures

– Incentives are project-based Payable by one-time lump sum check, per project

– Incentive agreement must be signed before equipment is purchased

– Check our website for participation steps and online forms

*Commercial retrofit projects must be at least 20,000 sq. ft. to be eligible

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Contacts

– For more information please phone us: Call your Business Solutions Team for answers to service and account

questions at 1-866-870-3419– Visit our website at:

Business program page –

rockymountainpower.net/business Business Solutions Toolkit –

rockymountainpower.net/toolkit– Or contact us directly:

E-mail us at energy.expert@pacificorp.com Use our online inquiry form – rockymountainpower.net/inquiry Call our business Energy Services Hotline at 1-800-222-4335