SpecialProblems8-10 - SP9: 2 kg of saturated liquid water...

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Special Problems for ME 200 – Spring 2010 Special Problems 8, 9, & 10 Due Friday, February 5, 2010 SP8: A heat pump is used to maintain a house at a constant temperature of 23 ° C during the winter season. The house is losing heat through the walls and the windows at a rate of 16,000 W to the ambient while the heat generated within the house from its human occupants, lights, and appliances is 1,000 W. The heat pump has COP of 2.5. (a) Conduct an energy balance on the house. (b) Determine the required power input (W) for the heat pump. Now consider that summer arrives when the house starts gaining 16,000 W of heat from the outside. The heat generated within the house from its human occupants, lights, and appliances is 1,000 W. You now wish to use the heat pump as a refrigerator to maintain the temperature of the house at 23 ° C. The COP of the refrigerator is 1.5. (c) Determine the required power input (W) for the refrigerator.
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Unformatted text preview: SP9: 2 kg of saturated liquid water is completely vaporized at a constant pressure of 100 kPa inside a piston-cylinder device. (a) Draw the process on a P-v diagram, accurately labeling the states and showing the values for pressure and specific volume. (b) Determine the change in specific volume (m 3 /kg) during the process. (c) Calculate the work (kJ) associated with the process. (d) Calculate the change in internal energy (kJ) during the process. (e) Calculate the amount of heat transfer (kJ) associated with this process. SP10: An 80 L vessel contains 4 kg of R-134a at a pressure of 160 kPa. (a) Locate the state of the refrigerant accurately on P-v and T-v diagrams. (b) What is the temperature (C) of the refrigerant? (c) Determine the quality of the refrigerant. (d) What is the enthalpy (kJ) of the refrigerant? (e) Calculate the volume (m 3 ) occupied by the vapor phase....
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This note was uploaded on 04/29/2010 for the course ME 200 taught by Professor Gal during the Spring '08 term at Purdue University-West Lafayette.

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