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Unformatted text preview: which? 5. Compute the efficiency of a 2 ton heat pump in heating mode for following conditions. Refrigerant-R-134A Indoor temperature-70 F Outdoor temperatures-40, 20, 0 F Compressor isentropic efficiency-70% Sketch the cycle on a P-h diagram for each outdoor temperature condition on the same plot. Graph the efficiencies (kW/ton or COP) for all three outdoor temperature cases to see how efficiencies vary. 6. For the conditions in problem 5, compute the threshold price for gas ($/therm) in which the heat pump is equivalent in cost to gas heat. You may assume efficiency of the gas furnace to be 80%. Any conclusions?...
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This note was uploaded on 08/01/2008 for the course MAE 406 taught by Professor Eckerlin,terry during the Fall '07 term at N.C. State.
- Fall '07