DOE/GO-10099-379
FS 206
June 1999 E NERGY
E FFICIENCY Energy-Efficient
AND
R ENEWABLE Air Conditioning
E NERGY
Are you considering buying a new air
conditioner? Or, are you dissatisfied with
the operation of your current air condi
tioner? Are you unsure whether to fix or
replace it? Are you concerned about high
summer utility bills? If you answered yes
to any of the questions, this publication
can help. With it, you can learn about
various types of air conditioning systems
and how to maintain your air conditioner,
hire professional air conditioning rvices,
toefl考试时间lect a new air conditioner, and ensure
that your new air conditioner is properly
installed.
Understanding Air Conditioners This publication discuss both central and room air conditioners. H
eat pumps, which provide both home cooling and heating, are not covered in this publication. Contact the Energy Efficiency and Renewable Energy Clearinghou (EREC–e Source List below) for more information about heat pumps of all kinds. How Air Conditioners Work
Air conditioners employ the same operating principles and basic components as your home refrigerator. An air conditioner cools your home with a cold indoor coil called the evaporator. The condenr, a hot outdoor coil, releas the collected heat
refrigerant through the circuit of tubing and fins in the coils. The liquid refrigerant evaporates in the indoor evaporator coil, pulling heat out of indoor air and thereby cooling the home. The hot refrigerant gas is pumped outdoors into the condenr where it reverts back to a liquid giving up its heat to the air flowing over the condenr’s metal tubing and fins.
Types of Air Conditioners
The basic types of air conditioners are room air conditioners, split-system central air conditioners, and packaged central air conditioners.
Room Air Conditioners
Room air conditioners cool rooms rather than the entire home. If they provide cooling only where they're needed, room air conditioners are less expensive to operate than central units, even though their efficiency is generally lower than that of central air conditioners.
Smaller room air conditioners (i.e., tho drawing less than 7.5 amps of electricity) can be plugged into any 15- or 20-amp, 115-volt houhold circuit that is not shared with any other major appliances. Larger room air conditioners (i.e., tho drawing more than 7.5 amps) need their own dedicated 115-
volt circuit. The largest models require a dedicated Room air conditioners are installed directly in windows or walls, which means they have no ductwork. The evaporator’s fan faces indoors, while the condenr’s fan faces outdoors.
Room Air Conditioner
Cabinet cover
Condenr
Filter
Condenr fan
Evaporator fan Evaporator
Central Air Conditioners
Central air conditioners circulate cool air through a system of supply and return ducts. Supply ducts and registers (i.e., openings in the walls, floors, or ceilings covered by grills) carry cooled air from the
air conditioner to the home. This cooled air becomes warmer as it circulates through the home; then it flows back to the central air conditioner through return ducts and registers. A central air conditioner is either a split-system unit or a packaged unit.
In a split-system central air conditioner , an outdoor metal cabinet contains the condenr and compressor, and an indoor cabinet contains the evaporator. In many split-system air conditioners, this indoor cabinet also contains a furnace or the indoor part of a heat pump. The air
conditioner’s evaporator coil is installed in the cabinet or main supply duct of this furnace or heat pump. If your home already has a furnace but no air
emphasizeconditioner, a split-system is the most
economical central air conditioner to install. In a packaged central air conditioner, the evaporator, condenr, and compressor are all located in one cabinet, which
usually is placed on a roof or on a concrete slab next to the hou’s foundation. This type of air conditioner also is ud in small commercial buildings. Air supply and return ducts come from indoors
through the home’s exterior wall or roof to connect with the packaged air conditioner, which is usually located outdoors. Packaged air conditioners often include electric heating coils or a natural gas furnace. This combination of air conditioner and central heater eliminates the need for a parate furnace indoors.
Maintaining Existing Air Conditioners
Older air conditioners may still be able to offer years of relatively efficient u. However, making your older air conditioner last requires you to perform proper operation and maintenance.
Evaporative Cooler
J o h n K r i g g e r
The most important maintenance task that will ensure the efficiency of your air conditioner is to routinely replace or clean its filters.
Regular Maintenance
An air conditioner’s filters, coils, and fins require regular maintenance for the unit to function effectively and efficiently菜鸟在线
throughout its years of rvice. Neglecting necessary maintenance ensures a steady decline in air conditioning performance while energy u steadily increas.
Air Conditioner Filters
行尸之惧 第二季The most important maintenance task that will ensure the efficiency of your air conditioner is to routinely replace or clean its filters. Clogged, dirty filters block normal air flow and reduce a system’s efficiency significantly . With normal air flow obstructed, air that bypass the filter may carry dirt directly into the evaporator coil and
impair the coil’s heat-absorbing capacity. Filters are located somewhere along the return duct’s length. Common filter
locations are in walls, ceilings, furnaces, or in the air conditioner itlf.
Some types of filters are reusable; others must be replaced. They are available in a variety of types and efficiencies. Clean or replace your air conditioning system’s filter or filters every month or two during the cooling ason. Filters may need more frequent attention if the air conditioner is in constant u, is subjected to dusty conditions, or you have fur-bearing pets
reduces its ability to absorb heat.
Therefore, your evaporator coil should be checked every year and cleaned as necessary.
Outdoor condenr coils can also become very dirty if the outdoor environment is
dusty or if there is foliage nearby. You can
easily e the condenr coil and notice if dirt is collecting on its fins.
产地英文You should minimize dirt and debris near the condenr unit. Your dryer vents, falling leaves, and lawn mower are all potential sources of dirt and debris.
Cleaning the area around the coil, removing any debris, and trimming foliage back at least 2 feet (0.6 meters) allow for adequate air flow around the condenr.
Coil Fins
The aluminum fins on evaporator and condenr coils are easily bent and can block air flow through the coil. Air
conditioning wholesalers ll a tool called a “fin comb” that will comb the fins back into nearly original condition.
Sealing and Insulating Air Ducts
An enormous waste of energy occurs when cooled air escapes from supply ducts or when hot attic air leaks into return ducts. Recent studies indicate that
Ducts must be aled with duct “mastic.” The old standby of duct tape is ineffective for aling ducts.
Obstructions can impair the efficiency of a duct system almost as much as leaks. You should be careful not to obstruct the flow of air from supply or return registers with furniture, drapes, or tightly fitted interior doors. Dirty filters and clogged evaporator coils can also be major obstructions to air flow.
toyboxThe large temperature difference between attics and ducts makes heat conduction through ducts almost as big a problem as air leakage and obstructions. Ducts in attics should be insulated heavily in addition to being made airtight.
Buying New Air Conditionersbaronet
Today’s best air conditioners u 30% to 50% less energy to produce the same amount of cooling as air conditioners made in the mid 1970s. Even if your air conditioner is only 10 years old, you may save 20% to 40% of your cooling energy costs by replacing it with a newer, more efficient model.
Sizing Air Conditioners
Air conditioners are rated by the number of British Thermal Units (Btu) of heat they can remove per hour. Another common rating term for air conditioning size is the “ton,” which is 12,000 Btu per hour. How big should your air conditioner be? The size of an air conditioner depends on: • how large your home is and how many windows it has;
• how much shade is on your home’s windows, walls, and roof;
人力资源会计• how much insulation is in your home’s ceiling and walls;
• how much air leaks into your home from the outside; and
• how much heat the occupants and appliances in your home generate. An air conditioner’s efficienc
y , performance, durability, and initial cost depend on matching its size to the above factors. Make sure you buy the correct size of air conditioner. Two groups—the Air Conditioning Contractors of America (ACCA) and the American Society of Heating, Refrigerating, and Air Conditioning
Engineers (ASHRAE)—publish calculation procedures for sizing central air conditioners. Reputable air conditioning contractors will u one of the procedures, often performed with the aid of a computer, to size your new central air conditioner. Be aware that a large air conditioner will not provide the best cooling. Buying an oversized air conditioner penalizes you in the following ways.
• It costs more to buy a larger air conditioner than you need.
• The larger-than-necessary air condi
tioner cycles on and off more frequently, reducing its efficiency. Frequent cycling makes indoor temperatures fluctuate more and results in a less comfortable environment. Frequent cycling also inhibits moisture removal. In humid climates, removing moisture is esntial for acceptable comfort. In addition, this cycling wears out the compressor and electrical parts more rapidly.
齐桓公读音是什么• A larger air conditioner us more electricity and creates added demands on electrical generation and delivery systems.
职称英语教材Air Conditioner Efficiency
Each air conditioner has an energy-efficiency rating that lists how many Btu per hour are removed for each watt of power it draws. For room air conditioners, this efficiency rating is the Energy
Efficiency Ratio, or EER. For central air conditioners, it is the Seasonal Energy Efficiency Ratio, or SEER. The ratings are posted on an Energy Guide Label, which must be conspicuously attached to all new air conditioners. Many air conditioner manufacturers are participants in
