Transcript Cooling Measures

WEATHERIZATION ENERGY AUDITOR SINGLE FAMILY
Cooling Measures
WEATHERIZATION ASSISTANCE PROGRAM STANDARDIZED CURRICULUM – December 2012
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ASSISTANCE PROGRAM STANDARDIZED CURRICULUM – December 2012
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Learning Objectives
COOLING MEASURES
By attending this session, participants will be able to:
• Discuss allowable cooling measures and general
guidelines for recommending them.
• Describe the benefits, qualities, and applications of
solar film (also called window film) and other shading
options.
• Explain how air sealing and insulating the home and
sealing and insulating ducts in unconditioned areas
conserves energy.
• State the benefits and qualities of reflective roof coating.
• Describe cleaning, tune-up and replacement strategies
for a variety of air cooling appliances.
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General Guidelines
COOLING MEASURES
Recommend cooling measures if:
• Usage profile indicates spike in summer usage.
• Family uses 1,000 kWh/yr or more for air
conditioning.
Exceptions can be made for:
• Small homes.
• Special circumstances (e.g., an elderly person needs
cooling in a single room).
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Allowable Measures
COOLING MEASURES
• Shading, louvers, or solar film on south-, west-, and eastfacing windows
• Sealing and insulating ducts in unconditioned spaces
• Reflective/White roof coating installed on:
- Awnings.
- Window louvers.
- Doors.
- Exterior ductwork.
• Clean/tune-up/replace cooling equipment
• Insulation and air-sealing
• General waste heat reduction
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Solar Film/Shading
COOLING MEASURES
Recommended for:
• South-, west- and
east-facing windows
not shaded during
summer months.
• When solar gain
overheats room
Photo courtesy of The U.S. Department of Energy
causing increase in
A/C use.
This window is already shaded by a nearby
tree. Evaluate cooling-season exposure to
determine cost-effectiveness of window
shades or solar films.
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Exposure to Sun
COOLING MEASURES
• Take the path of the sun into account.
• Some windows on the south side may be shaded by
overhangs in summer, only exposed in winter.
Illustrations courtesy of Florida Solar Energy Center, www.fsec.ucf.edu.
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Solar Film/Shading Tips
COOLING MEASURES
• Determine window exposure with appropriate tool (e.g.,
Solar Pathfinder).
• Show client sample of shading fabric, louvers, or window
film to be installed.
Photos courtesy of The U.S. Department of Energy
The Solar Pathfinder is useful for
determining summertime exposure
any time of the year.
Show client a sample of recommended
shading device or film before specifying
for the job.
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Window Film Guidelines
COOLING MEASURES
• Shading coefficient of
0.40 or lower
• U-factor of 1.0 or lower
• “Total solar energy
rejected” is at least 65.
• Film is approved by
manufacturer for use on
insulated glass and
insulated panels
Film is applied to the cleaned
interior of eligible windows and
doors and smoothed.
Photo courtesy of A. Tamasin Sterner, Chapter 10 “Cooling Measures,” PPL Electric Utility Winter Relief Asset Program Standards, 2007
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Sealing and Insulating Ducts
COOLING MEASURES
• Seal and insulate ducts in
unconditioned areas.
• Keep conditioned air
where client needs it.
• For more details on duct
leakage testing and
sealing, refer to Building
Shell Retrofit Options
section.
Specify duct sealing to achieve
pressure pan readings of less
than two (2) Pa.
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Photo courtesy of The U.S. Department of Energy
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Specify: Seal and insulate ducts
running through unconditioned spaces
in accordance with program standards.
Photo courtesy of The U.S. Department of Energy
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Photo courtesy of The U.S. Department of Energy
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Photo courtesy of The U.S. Department of Energy
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While checking duct
conditions, note if they should
be cleaned, like this one.
Photo courtesy of The U.S. Department of Energy
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Cleaned and sealed
Photo courtesy of The U.S. Department of Energy
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Where wall cavities are used
as ducts, specify duct or
metal pan installation.
Photo courtesy of The U.S. Department of Energy
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Roof Coatings
COOLING MEASURES
• Solar Reflectance =
65% or higher when new
• Thermal Emittance =
80% to 90% or more
• Elastomeric:
- Water-proofing
- Flexible
Photo courtesy of A. Tamasin Sterner
• Cementitious:
- Relies on underlying
membrane for
waterproofing
Reflective roof coatings, shown here on a
row house, can carry a heating penalty due
to reflected winter sun, but in most urban
areas, savings outweigh heating losses.
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Reflective Roof Coating
COOLING MEASURES
Consider white reflective roof coating if roof receives
full sun during cooling season.
These coatings:
• Reflect solar radiation, cutting cooling loads 10%-60%.
• Can extend life of roof, and elastomeric varieties protect
from water penetration.
• Can be applied over common roofing materials.
• Typically last 7–12 years.
Average cost is between $0.75 and $1.50 per square foot
for materials and labor (not including incidental repairs).
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Color Affects Surface
Temperature
COOLING MEASURES
Albedo, or solar reflectance, can significantly influence surface
temperature, with the white stripe on the brick wall about 5 to 10°F
(3 to 5°C) cooler than the surrounding, darker areas.
Photos courtesy of the EPA’s “Reducing Urban Heat Islands, A Compendium of Strategies. 2008
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Reflective Roof Coating
Guidelines
COOLING MEASURES
• Primer is often required.
• Prime metal roofs for proper adhesion and to prevent
rust from progressing.
• For pre-1976 mobile homes, scaffolding helps installers
avoid walking on, and potentially damaging, the roof.
• Typical installation includes primer, plus two coats.
• Educate clients to wash roof periodically.
• Remember to evaluate cost-effectiveness!
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Clean/Tune Up/Replacing
Cooling Systems
COOLING MEASURES
• Remove obstructions
to airflow.
• Clean condenser coils.
• Clean evaporator, if
accessible.
• Clean/replace filters.
Photo courtesy of The U.S. Department of Energy
• Insulate coolant line.
• Level unit.
• Test/adjust coolant charge (requires EPA-licensed
refrigeration technician).
• If replacing coolent system, properly size replacement.
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Air Conditioning Systems
COOLING MEASURES
Air Conditioning Units
Split System:
Packaged:
• Condenser outdoors
• Heat pump
• Central system
• A/C coil indoors, often in
furnace, heat pump, or
• Often mounted on
CONDENSER
supply duct
roof or concrete slab
outdoors
AIR HANDLER
• Includes room A/C
units (most common
in low income homes)
* All A/C need clean filters and coils to allow
good air flow and efficiently transfer heat.
Mini-split ductless systems place the condenser
outdoors, air handler indoors.
Photos courtesy of The U.S. Department of Energy
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Indoor and Outdoor Coils
COOLING MEASURES
Outdoor:
• Cleaning frequency depends
on levels of dust and pollen in
area.
• High levels: Clean annually.
• Low levels: Every three years.
Indoor:
• Should be protected by
well-fitting clean filter.
• Keeps blower and coils clean.
• Easier to replace or clean
filters than blowers or coils.
Outdoor Coils
Indoor Coils
Source: Energy Out West Weatherization Field Guide. Copyright Saturn 2009 www.srmi.biz
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Cleaning Indoor Coils
COOLING MEASURES
1.
2.
3.
4.
5.
6.
7.
Shut off the main switch to the air handler.
Open the blower compartment and evaluate fan blades.
If the blower is dirty, remove and clean it.
If the blower is dirty, inspect the indoor coil visually.
If the coil is dirty, clean it.
Straighten bent fins.
Clean the drain pan and drain line.
Source: Energy Out West Weatherization Field Guide. Copyright Saturn 2009 www.srmi.biz
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Clean room air conditioners
Photo courtesy of The U.S. Department of Energy
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Parts of Room A/C
COOLING MEASURES
indoor coil
compressor
condensate drain
Photo courtesy of Energy Out West Weatherization Field Guide. Copyright Saturn 2009 www.srmi.biz
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Cleaning Room A/C
COOLING MEASURES
1. Remove the grill and filter on the interior side of the unit.
2. Unplug and remove the air conditioner temporarily from the window or
wall.
3. Take the unit to a clean outdoor area that drains well.
4. Cover the compressor, fan motor, and electrical components.
5. Dampen each of the coils, and then rake as much dirt off the coils as
you can.
6. Spray coil cleaner into the coils and let the cleaner set.
7. Rinse the cleaner and dirt out of the coils.
8. Repeat the process until the water draining from the coils is clean.
9. Straighten bent fins.
Source: Energy Out West Weatherization Field Guide. Copyright Saturn 2009 www.srmi.biz
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Remove the housing and
removable grille to access
parts for cleaning.
Photo courtesy of The U.S. Department of Energy
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Use outdoor coil cleaner
for outdoor coils.
Photo courtesy of The U.S. Department of Energy
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Remove the removable
grille to assess filter.
Photo courtesy of The U.S. Department of Energy
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This filter is doing a good
job stopping dust and dirt
from dirtying the coils.
Photo courtesy of The U.S. Department of Energy
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The newly cleaned filter will
continue to keep the coils clean.
Photo courtesy of The U.S. Department of Energy
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Moisture dripping from bottom
of unit may indicate a clogged
condensate drain.
Photo courtesy of The U.S. Department of Energy
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Clogged condensate drains
can lead to moisture
damage.
Photo courtesy of The U.S. Department of Energy
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Sill is repaired before
replacing unit.
Damaged insulation and
siding has been removed.
Photo courtesy of The U.S. Department of Energy
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Note air sealing around
“through the wall” unit.
Photo courtesy of The U.S. Department of Energy
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Central A/C Components
COOLING MEASURES
The outdoor condenser and
coils dissipate collected heat
to the outdoor air. In dusty
climates, the coils should be
cleaned annually to maintain
efficient performance.
Source: Energy Out West Weatherization Field Guide. Copyright Saturn 2009 www.srmi.biz
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Servicing Central A/C
Evaporator
COOLING MEASURES
If appropriate, specify cleaning the evaporator.
• Clean underside with stiff brush.
• Clean tray below evaporator.
• Pour bleach into weep hole.
• Open clogged weep hole.
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Servicing Central A/C
Condenser
COOLING MEASURES
If appropriate, specify servicing the condenser.
• Remove anything obstructing air flow.
• Clean coils.
• Clean fins.
• Straighten bent fins.
• Level unit.
• Educate clients on proper care and maintenance.
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Covering the unit during periods
of disuse prevents clogging with
leaves and other debris.
Photo courtesy of The U.S. Department of Energy
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Inspect Coolant Line
COOLING MEASURES
• Inspect cooling line.
• Specify insulation where
needed.
This insulation has eroded.
Specify new insulation for this line.
Photo courtesy of The U.S. Department of Energy
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Refrigerant Charge Effects EER
COOLING MEASURES
Comparison of TXV and Fixed-Orifice XV:
EER vs. Charge at 95°F Outdoor Temperature
Photo courtesy of M. Farzad, D.L. O’Neal, Texas A&M University
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Refrigerant Charge Testing #1
COOLING MEASURES
Before Testing and Adjusting:
•
•
•
•
•
Outdoor temp at least 60F
Measure and adjust airflow
Test and seal ducts
Clean condenser coil, allow to dry completely
All testing and refrigerant handling –
Qualified and EPA licensed refrigeration technician
Required Equipment for Testing/Adjusting:
• DOT recovery cylinder for removal
• Refrigeration gauge set
• Digital thermometer with wet cloth (for wet bulb) or sling
psychrometer
Source: Energy Out West Weatherization Field Guide. Copyright Saturn 2009 www.srmi.biz
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Refrigerant Charge Testing #2
COOLING MEASURES
Superheat test
Subcooling test
• Use for fixed-orifice or capillary tube
system
• Use for thermal expansion valve
system
• Airflow must be ≥ 400 CFM per ton
• Outdoor temperature must be ≥ 60F
• Outdoor temperature must be ≥ 60F
• Air conditioner or heat pump should
be running in cooling mode for at least
10 minutes prior to testing
• Charge checking at very high outdoor
temperatures not recommended
Superheat is the temperature
difference between the
evaporator and the
compressor inlet.
Subcooling is the temperature
difference between the middle of
the condenser and the liquid
service valve outside.
Photo Courtesy of Energy
Out West Weatherization
Field Guide. Copyright
Saturn 2009 www.srmi.biz
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Refrigerant Charge Superheat Test
COOLING MEASURES
Use evaporator superheat test for capillary-tube
or fixed-orifice expansion devices, operating in the
cooling mode:
• Verify adequate airflow.
• Measure dry bulb temp of air entering outdoor coil.
• Measure wet bulb temp of return air at air handler.
• Use superheat table to determine recommended superheat temp.
• Measure and evaluate compressor-suction pressure at suction service valve.
• Measure and evaluate suction line temperature.
• If superheat temp is high, add refrigerant, wait 10 minutes and repeat test.
• If superheat temp is low, remove refrigerant, wait 10 minutes and repeat test.
• For more complete instructions, refer to Section 3.8 of the Energy Out West
Field Guide.
Image courtesy of Energy Out West Weatherization Field Guide
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Refrigerant Charge Subcooling Test
COOLING MEASURES
Use subcooling test for thermal expansion valve (TXV) devices:
• Measure and convert liquid pressure at liquid service valve.
• Measure temperature of liquid refrigerant
leaving condenser.
• Subtract liquid-refrigerant temp from converted
condensing temp. This is subcooling.
• Compare to correct subcooling (from permanent
sticker in condenser, manufacturer’s literature
or slide-rule).
• If more than 3F variation, adjust levels.
• Let system run 10 minutes and repeat test.
• For more complete instructions, refer to Section 3.8 of the Energy Out West
Field Guide.
Image courtesy of Energy Out West Weatherization Field Guide. Copyright Saturn 2009 www.srmi.biz
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Replacing a Room A/C
COOLING MEASURES
• If cost-effective, replace existing unit
with properly-sized, high-efficiency
model. Look for models that carry the
ENERGY STAR logo.
Area to be Cooled
(square feet)
Capacity Needed
(BTUs per hour)
100 to 150
5,000
150 to 250
6,000
250 to 300
7,000
300 to 350
8,000
Sizing Adjustments:
350 to 400
9,000
• Heavily shaded – Reduce capacity by
10%
400 to 450
10,000
450 to 550
12,000
• Very sunny – Increase capacity by
10%
550 to 700
14,000
700 to 1,000
18,000
1,000 to 1,200
21,000
• If installed in a corner, choose unit that
can direct airflow in appropriate
direction.
• Add 600 BTUs per person that usually
occupy the room after the second
• In kitchen – Add 4,000 BTUs
Photo courtesy of ENERGY STAR program; www.energystar.gov
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Summary
COOLING MEASURES
• Allowable cooling measures include window shading, roof
coating, shell and duct sealing and insulation, and
cleaning/tune-up/replacement of air cooling appliances.
• Cooling measures are generally recommended when
household cooling energy use ≥ 1,000 kWh/year.
• As with any weatherization measures, SIR must be ≥ 1.
• Windows and roofs should be evaluated for solar exposure
during cooling season.
• Air conditioners should be level, coils clean and
unobstructed,
and have proper refrigerant charge to operate efficiently.
• If replacing a unit, properly size according to Manual J or
ENERGY STAR guidelines (room A/C).
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