Unformatted text preview: ing can be provided by trees and other vegeta3on Most central air condi3oning systems are "split" systems. Correct A ) T RUE Most central air condi3oning systems are "split" systems. Which term is used to describe the eﬃciency of air source heat pumps? Correct D ) H SPF HSPF is used to describe the eﬃciency of air source heat pumps A contractor says the home requires a 1 ton air condi3oning system. How many BTUS does this system pull out each hour? Correct C ) 12000 Btus 1 ton of air condi3oning is equivalent to 12000 BTUs/hr The size of an air condi3oner depends on the insula3on in the ceiling and walls of the house. Correct A ) T RUE The size of an air condi3oner depends on 1. how large the home is and how many windows it has, 2. how much shade is on your home's windows, walls and roofs, 3. the insula3on in the ceiling and walls of the house, 4. on the quan3ty of air that leaks into a house from the outside, 5. on the heat generated by the occupants and appliances in the house. If the owner replaces his old 1 ton air condi3oner (SEER=7) with a new 1 ton air condi3oner (SEER=15), which costs $454 more, what is the payback period? Assume that the air condi3oner is operated for about 2000 hrs in a year and the cost of electricity is 10 cents per kWh. (5 Points) Correct D ) 2.48 years We know that, 1 ton of air condi3oning = 12000 BTU/hr
Old air condi3oner
Power consump3on = 1 x 12000 / 7 = 1714.285 wa\s
Energy cost = 1714.285 x 2000 / 1000 x 10 / 100 = $342.85
New air condi3oner
Power consump3on = 1 x 12000 / 15 = 800 wa\s
Energy cost = 800 x 2000 / 1000 x 10 / 100 = $160
Savings in energy cost = 342.85  160 = $182.85
Pay Back period = 454 / 182.85 = 2.482 yrs When air is heated its rela3ve humidity ________ Correct A ) Decreases When air is heated its rela3ve humidity decreases If the owner replaces his old 2 ton air condi3oner (SEER=12) with a new 2 ton air condi3oner (SEER=14), which costs $462 more, what is the payback period? Assume that the air condi3oner is operated for about 2000 hrs in a year and the cost of electricity is 11 cents per kWh. (5 Points) Correct D ) 7.35 years We know that, 1 ton of air condi3oning = 12000 BTU/hr
Old air condi3oner
Power consump3on = 2 x 12000 / 12 = 2000 wa\s
Energy cost = 2000 x 2000 / 1000 x 11 / 100 = $440
New air condi3oner
Power consump3on = 2 x 12000 / 14 = 1714.285 wa\s
Energy cost = 1714.285 x 2000 / 1000 x 11 / 100 = $377.14
Savings in energy cost = 440  377.14 = $62.85
Pay Back period = 462 / 62.85 = 7.349 yrs...
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This note was uploaded on 09/24/2013 for the course EGEE 102 taught by Professor Pisupati,sarmave during the Spring '07 term at Penn State.
 Spring '07
 PISUPATI,SARMAVE

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