Chapter 5, Problem 5.33P

A heat engine has a solar collector receiving 600 Btu/h per square foot, insidewhich a transfer medium is heated to 800 R. The collected energy powers aheat engine that rejects heat at 100 F. If the heat engine should deliver 8500Btu/h, what is the minimum size (area) of the solar collector?

A bio-reactor is kept at 42°C by a heat pump driven by a motor of 2 kW. The reactor loses energy at a rate of 0.5 kW per degree difference to the colder ambient. The heat pump has a COP that is 50% that of a Carnot heat pump. What is the minimum ambient temperature for which the heat pump is sufficient?

6.24 A heat pump system operates between temperature limits of -5 and 18°C. The heating load of the space is 48,000 Btu/h and the COP of the heat pump is estimated to be 1.7. Determine (a) the power input, (b) the rate of heat absorbed from the cold environment, and (c) the maximum possible COP of this heat pump.

1. Water in the rural areas is often extracted from underground water source whose free surface is 60 m below ground level. The water is to be raised 5 m above the ground by a pump. The diameter of the pipe is 10 cm at the inlet and 15 cm at the exit. Neglecting any heat interaction with the surroundings and fictional heating effects. What is the necessary power input to the pump in kW for a steady flow of water at the rate of 15 li/s? Assume pump efficiency of 74%.

3.3 Would it be possible to use a normal domestic refrigerator as a heat source for a small hot tub or whirlpool? If so, what would you estimate to be the maximum heating rate and temperature that a 300 gal whirlpool could reach using a refrigerator that is sized to use a 1 hp electric compressor designed with an evaporator temperature of 10 ° F and condensing temperature of 125 ° F?

2) When the pressure increase lead to volume is A: Increase B: Decrease C: Constant Q7: An air conditioning system is used to maintain a house at a constant temperature of 20 C. The house is gaining heat from outdoors at a rate of 21000 kJ/h, and the heat generated in the house from the people, lights, and appliances amounts to 9000 kJ/h. For a COP of 2.4, determine the required power input to this air conditioning system. Your answer

2.Two Carnot heat engines run in series with the efficiency of first engine is k times the second. If the thermal reservoir at low and high temperatures were denoted by TL and TH, find the simplified ratio of heat absorbed to heat rejected by the second heat engine in terms of TL, TH and k only.

An irreversible heat pump with COP of 2.4 is used to heat water to 80°C for cleaning purposes. This heat pump absorbs heat from surrounding at 30°C and received the entire power, W from a Carnot heat engine operating between 250°C and 30°C. The Canot heat engine received 6.3 kW of heat from the high temperature source. i) Draw the schematic diagram of the above system. ii) Determine the power received by the heat pump, W from Carnot heat engine, kW. i1) Calculate the rate of heat supplied to the water by the heat pump, kW. iv) Determine the COP of the heat pump if it operates on a reversed Carnot cycle.

the energy transffered by heat from an engine during one cycle is 500J. how much energy must be added to the engine so that it can operate at 30 %