SpecialProblems35-37

# SpecialProblems35-37 - an isentropic turbine Determine the new rate of heat transfer in kW from the cold temperature region Determine the

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Special Problems for ME 200 - Spring 2011 Problems Due on April 22, 2011 SP35: a) Do the following quantities increase, decrease, or remain the same when an ideal superheat Rankine cycle is modified to include reheating? Assume both cycles operate between the same pressure limits and that the maximum temperature remains the same. Use 1 st and/or 2 nd Law arguments to explain why quantities change (or don’t change) in the manner indicated. Pump work input Turbine work output Heat supplied Heat rejected Quality at turbine exit b) Draw a T-s diagram for an ideal Rankine cycle with two stages of reheating. At the inlet of the first turbine, the working fluid is a superheated vapor. Assume that the inlet temperature to each turbine is the same. Show lines of constant pressure. Clearly indicate which properties remain constant in each process of the cycle. SP36: Using the ideal vapor-compression refrigeration cycle found in Example 10.1 of the textbook, find the work that would be produced in kW if the throttling valve were replaced with
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Unformatted text preview: an isentropic turbine. Determine the new rate of heat transfer in kW from the cold temperature region. Determine the corresponding increase in the COP of the refrigerator. Note: You do not need to reproduce the solution of Example 10.1 found in the textbook, but you must follow the problem solving format and state what information you are using from the solution found in the textbook. SP37: A house is maintained at 75°F in the winter by a heat pump. The house is losing heat at a rate of 60,000 Btu/h through the walls and roof. The heat pump operates on an ideal vapor-compression cycle and uses underground water at 50°F as the heat source. The working fluid is refrigerant-134a. The evaporator and condenser pressures are 50 and 120 psia, respectively. Determine the power input in horsepower to the heat pump and the electric power saved in horsepower by using a heat pump instead of an electric resistance heater....
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## This note was uploaded on 04/23/2011 for the course ME 200 taught by Professor Gal during the Spring '08 term at Purdue University-West Lafayette.

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