Energy Management Opportunities
in
Heating, Ventilation and Air
Conditioning (HVAC)
Your panelists
– Benefits, Technologies & Services:
Mike Carter and Mark Farrell,
Energy Engineers
2
Why is HVAC important?
– Productivity
– Comfort
– Expense
Source: www.doe.gov
Source: www.bcs.org
3
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
4
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.
Source: stock.xchng
• 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.
Source: Commonwealth of Kentucky
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)
5
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
100%
55
55
60%
48
42
40%
45
37
30%
Not Sustainable
Ice
55
6
Source: Microsoft Encarta
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
In this example, specific (absolute)
humidity does not change until the
dew point is reached.
H2O
100%
Relative
Humidity
7
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
8
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.
9
HVAC basics
– HVAC Load Hours
Source: Louisiana Department of Natural Resources, Technology Assessment Division
10
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
FLV
COP
(kW/ton)
Application Part Load Value (APLV)
0.6
5.9
• Other than full load
Integrated Part Load Value (IPLV)
0.75
4.7
• Weighted average of full load and part load
1.0
3.5
1.5
11
2.3
EER
20
16
12
8
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
12
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
13
HVAC basics
– Vapor Compression/Expansion Cycle
Source: www.makinemekanik.com
14
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
ODP
GWP
Application
1
2
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
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
2Global
15
Depletion Potential
Warming Potential
R-11 replacement
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.
16
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.
17
Cooling
Source: EERE
– Chillers
Source: ORNL
Centrifugal Chiller
Chiller Minimum Efficiency Requirements (ASHRAE 90.1-2004)
Compressor Type/Capacity
Full-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
18
Best available Full-Load FLV is
0.47-0.58 kW/ton for large
(>150 ton) water-cooled chillers
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

100-ton
Cost Category
500-ton
Air
Water
Air
Water
Initial
50%
68%
22%
42%
Energy
40%
20%
63%
45%
Maintenance
10%
12%
15%
13%
Initial
72%
78%
45%
60%
Energy
16%
10%
35%
20%
Maintenance
12%
12%
20%
20%
New York City
Minneapolis
Source: Total Cost of Ownership For Air-Cooled and
Water-Cooled Chiller Systems, Ramez Naguib
19
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
20
Cooling / heating
– Packaged Rooftop
Image courtesy of McQuay International
Unitary Air Conditioner Minimum Efficiency Requirements
ASHRAE 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
21
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 90.1-2001
Replacement
Cooling
Source: www.amana-ptac.com/
New
Construction
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
22
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
100-500'
300-400'/ton
Horizontal
5-6'
800'/ton
Pond
>8'
400'/ton
Vertical
Image courtesy of ECS Geothermal
23
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
Image courtesy of Coil-Tech
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.
24
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
25
Source: Precision Boilers
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

26
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
<30
On
Closed
Modulated Economizer
30-55
Off
Varies
Integrated Economizer
55-75
On
Open
>75
On
Closed
Heating
Cooling
27
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
28
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
29
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
30
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
31
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.
32
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
33
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
34
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
35
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
36
What is in the Toolkit
37
Online business tools
rockymountainpower.net/toolkit
38
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 highefficiency 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
39
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
40
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
41