1. Energy Management Opportunities in Heating, Ventilation and Air Conditioning (HVAC)

2. Your panelists
Benefits, Technologies & Services: Mike Carter and Mark Farrell, Energy Engineers

3. Productivity Comfort Expense Why is HVAC important?
Source:
Source:

4. 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

5. 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 energy consumption, 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

6. Dry Bulb Temperature (°F) Wet Bulb Temperature (°F)
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.
Source: Microsoft Encarta
Dry Bulb Temperature (°F)
Relative Humidity
Wet Bulb Temperature (°F)
Dew Point (°F) 70
100%
60% 61 56
30% 53 38 55 48 42
40% 45 37
Not Sustainable
Ice

7. 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.
4C 40F
100% Relative
Humidity
H2O
In this example, specific (absolute) humidity does not change until the dew point is reached.

8. 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

9. 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.

10. HVAC basics HVAC Load Hours
Source: Louisiana Department of Natural Resources, Technology Assessment Division

11. HVAC basics Efficiency Ratings
One ton (12,000 Btu/hr) equals 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 = (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

12. Seasonal Energy Efficiency Ratio (SEER)
HVAC basics
Seasonal Energy Efficiency Ratio (SEER)
Test conditions for determining SEER values are defined by ANSI/ARI standard
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

13. Estimation of annual operating cost
HVAC basics
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

14. HVAC basics Vapor Compression/Expansion Cycle
Source:

15. 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 systems
Refrigerant
ODP1
GWP2
Application
CFC-11
1.0
4,680
Centrifugal chillers
CFC-12
10,720
Chillers, refrigerators
HCFC-22
0.04
1,780
AC, chillers
HCFC-123
0.02 76
R-11 replacement
HFC-134a
<
1,320
R-12 or R-22 replacement
HFC-407c
1,700
R-22 replacement
HFC-410a
1,890 AC
1Ozone Depletion Potential 2Global Warming Potential

16. 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.

17. HVAC basics Indoor Air Quality
ASHRAE 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.

18. Cooling
Source: EERE
Chillers
Source: ORNL
Centrifugal Chiller
Chiller Minimum Efficiency Requirements (ASHRAE )
Compressor Type/Capacity
Full-Load Rating, COP (kBtu)
Full-Load Rating, FLV (kW/ton)
Part-Load Ratings, IPLV (kBtu)
Reciprocating ( tons)
4.20
0.84
5.05
Screw/Scroll (<150 tons)
4.45
0.80
5.20
Screw ( tons)
4.90
0.72
5.60
Screw ( tons)
5.50
0.64
6.15
Centrifugal (<150 tons)
5.00
0.70
5.25
Best available Full-Load FLV is kW/ton for large (>150 ton) water-cooled chillers

19. Cooling
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
Cost Category
100-ton
500-ton
Air
Water
New York City
Initial
50%
68%
22%
42%
Energy
40%
20%
63%
45%
Maintenance
10%
12%
15%
13%
Minneapolis
72%
78%
60%
16%
35%
Source: Total Cost of Ownership For Air-Cooled and
Water-Cooled Chiller Systems, Ramez Naguib

20. Chiller Maintenance Tips
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

21. Full-load EER (Btu/watt)
Cooling / heating
Packaged Rooftop
Image courtesy of McQuay International
Unitary Air Conditioner Minimum Efficiency Requirements ASHRAE
Full-load EER (Btu/watt)
Size Range
Pre-2010
As of 2010*
kBtu/hr (5-11 ton)
10.3
11.2
kBtu/hr (11-20 ton)
9.7
11.0
kBtu/hr (20-63 ton)
9.5
10.0
>760 kBtu/hr (>63 ton)
9.2
*Phase-out date for R-22 refrigerant

22. Packaged Terminal Air Conditioners (PTACs)
Cooling / heating
Packaged Terminal Air Conditioners (PTACs)
EER of 10 to 12 available today
Suppliers include Amana, Bard, Carrier, ClimateMaster, Friedrich, GE, and Skymark
PTAC/PTHP Minimum Efficiency Requirements ASHRAE
Replacement
New 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)
10.8
PTHP (15,000 Btuh)
7.6
9.1
Heating
Full-load COP (Kbtuh)
2.7
3.0
2.5
2.8
Source:

23. Geothermal or Water-Source Heat Pump
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
Image courtesy of ECS Geothermal
Loop
Depth
Length/ton
Vertical '
'/ton
Horizontal
5-6'
800'/ton
Pond
>8'
400'/ton

24. 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

25. Heating Electric Boilers Electrode Steam 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

26. 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

27. Economizers bring in cool outside air
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
Open
Cooling
>75

28. Heat Recovery Ventilators
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

29. Energy/Enthalpy/Desiccant Wheels
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

30. Thermal Energy Storage (TES)
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

31. Thermal Energy Storage (TES)
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

32. Accessories 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.

33. 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

34. 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

35. 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 box

36. 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

37. What is in the Toolkit

38. Online business tools rockymountainpower.net/toolkit

39. 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

40. 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

41. Contacts For more information please phone us: Visit our website at:
Call your Business Solutions Team for answers to service and account questions at
Visit our website at:
Business program page –
rockymountainpower.net/business
Business Solutions Toolkit –
rockymountainpower.net/toolkit
Or contact us directly: us
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