Home Cooling EGEE 102 — Pisupati Function

Home Cooling EGEE 102 - Pisupati

Function of an Air conditioner EGEE 102 - Pisupati 2

Humidity in air • Relative Humidity • A measure of of much water is in the air relative to the maximum amount air can hol at that tmperature EGEE 102 - Pisupati 3

EGEE 102 - Pisupati http: //www. ae. iastate. edu/Ast 473/Lectures/%285%29 Psychrometric_Chart/sld 024. htm 4

Principle A. Expansion Valve B. Compressor EGEE 102 - Pisupati 5

Arrangement EGEE 102 - Pisupati 6

TYPES OF AIR CONDITIONERS • • Room air conditioners Central air conditioning systems Heat pumps Evaporative coolers EGEE 102 - Pisupati 7

Air Conditioning EGEE 102 - Pisupati 8

Room air conditioner • Room air conditioners cool rooms rather than the entire home. • Less expensive to operate than central units • Their efficiency is generally lower than that of central air conditioners. • Can be plugged into any 15 - or 20 -amp, 115 -volt household circuit that is not shared with any other major appliances EGEE 102 - Pisupati 9

EGEE 102 - Pisupati 10

Central Air conditioning • 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 EGEE 102 - Pisupati 11

Types of Central AC • split-system • an outdoor metal cabinet contains the condenser and compressor, and an indoor cabinet contains the evaporator • Packaged • the evaporator, condenser, and compressor are all located in one cabinet EGEE 102 - Pisupati 12

Large air conditioning systems • Outside air is drawn in, filtered and heated before it passes through the main air conditioning devices. The colored lines in the lower part of the diagram show the changes of temperature and of water vapor concentration (not RH) as the air flows through the system. EGEE 102 - Pisupati 13

Total Air Conditioning EGEE 102 - Pisupati 14

• Variable fresh air mixer and dust and pollutant filtration. • Supplementary heating with radiators in the outer rooms and individual mini heater and • Humidifier in the air stream to each room. EGEE 102 - Pisupati 15

Sizing Air Conditioners • how large your home is and how many windows it has; • how much shade is on your home's windows, walls, and roof; • 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 EGEE 102 - Pisupati 16

Energy Consumption • 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. • Room air conditioners range from 5, 500 Btu per hour to 14, 000 Btu per hour. EGEE 102 - Pisupati 17

Energy Efficiency • Today's best air conditioners use 30% to 50% less energy than 1970 s • 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 EGEE 102 - Pisupati 18

Energy Efficiency • Rating is based on 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 EGEE 102 - Pisupati 19

Room Air Conditioners • Built after January 1, 1990, need have an EER of 8. 0 or greater • EER of at least 9. 0 if you live in a mild climate • EER over 10 for warmer climates EGEE 102 - Pisupati 20

Central AC • National minimum standards for central air conditioners require a SEER of • 9. 7 for single-package and • 10. 0 for split-systems • Units are available with SEERs reaching nearly 17 EGEE 102 - Pisupati 21

Energy Saving Methods • Locate the air conditioner in a window or wall area near the center of the room and on the shadiest side of the house. • Minimize air leakage by fitting the room air conditioner snugly into its opening and sealing gaps with a foam weather stripping material. EGEE 102 - Pisupati 22

Numerical Problem • A EER from 5. 0 to 9 saving and pay back period EGEE 102 - Pisupati 23