An inventor just invented a kind of heat engine that could operate at a maximum temperature of 1000K and minimum temperature of 300K. This heat engine is used to drive a heat pump which extracts heat from the reservoir at 300 K. Its capacity is operating at a rate twice that at which the engine rejects heat to it. If the efficiency of the engine is 40% of the maximum possible and the COP of the heat pump is 50% of the maximum possible, what is the temperature of the reservoir to which the heat pump rejects heat? What is the rate of heat rejection from the heat pump if the rate of heat supply to the engine is 50 kW?

An inventor just invented a kind of heat engine that could operate at a maximum temperature of 1000K and minimum temperature of 300K. This heat engine is used to drive a heat pump which extracts heat from the reservoir at 300 K. Its capacity is operating at a rate twice that at which the engine rejects heat to it. If the efficiency of the engine is 40% of the maximum possible and the COP of the heat pump is 50% of the maximum possible, what is the temperature of the reservoir to which the heat pump rejects heat? What is the rate of heat rejection from the heat pump if the rate of heat supply to the engine is 50 kW?

Refrigeration and Air Conditioning Technology (MindTap Course List)

8th Edition

ISBN:9781305578296

Author:John Tomczyk, Eugene Silberstein, Bill Whitman, Bill Johnson

Publisher:John Tomczyk, Eugene Silberstein, Bill Whitman, Bill Johnson

Chapter45: Domestic Refrigerators And Freezers

Section: Chapter Questions

Problem 12RQ: Refrigerators currently being manufactured in the United States are using______as their refrigerant.

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An inventor just invented a kind of heat engine that could operate at a maximum temperature of1000K and minimum temperature of 300K. This heat engine is used to drive a heat pump which extracts heat from the reservoir at 300 K. Its capacity is operating at a rate twice that at which the engine rejects heat to it. If the efficiency of the engine is 40% of the maximum possible and the COP of the heat pump is 50% of the maximum possible, what is the temperature of the reservoir to which the heat pump rejects heat? What is the rate of heat rejection from the heat pump if the rate of heat supply to the engine is 50 kW?
A gasoline truck engine takes in 10,000 J of heat and delivers 2,000 J of mechanical work per cycle. . What other machines utilize the concept of heat engine in its operation? Give at least 3 examples.
The temperature inside a kitchen freezer is a constant 256 K, while the temperature of the air in the kitchen is a constant 302 K. The freezer's insulation is imperfect, and it conducts energy into its interior at a rate of 0.150 W. Assuming the freezer can be approximated as ideal (operating in a Carnot cycle), what is the average power required by the freezer's motor to maintain the constant interior temperature? W Need Help? Read It DETA LC
The inventor decides to lower the temperature of the low-temperature reservoir using a Carnot refrigerator. This refrigerator is powered by the heat engine itself, not an external source, consuming part of the work output of the heat engine. Let the high temperature reservoir be at Th, the original low temperature reservoir be at T₁, and the even-lower temperature achieved by the refrigerator be Tr. a) Find the ratio of the net (available) work to the heat Qh supplied by the high-temperature reservoir. [You do not need to worry about the process of lowering part of the reservoir to Tr. Assume that this has already been done, and the Carnot refrigerator only needs to remove as much heat from the T, reservoir as the heat engine is supplying.] b) It is possible to obtain a higher net efficiency this way?
A heat pump with a COP of 3.2 is used to heat a perfectly sealed house (no air leaks). The entire mass within the house (air, furniture, etc.) is equivalent to 1200 kg of air. When running, the heat pump consumes electric power at a rate of 5 kW. The temperature of the house was 7°C when the heat pump was turned on. If heat transfer through the envelope of the house (walls, roof, etc.) is negligible, the length of time the heat pump must run to raise the temperature of the entire contents of the house to 22°C is (a) 13.5 min (b) 43.1 min (c) 138 min (d) 18.8 min (e) 808 min
2. Between 300K and 600K is the operating temperature of a pair of heat pumps connected in series. The efficiency of the second heat pump is three times that of the first. Find the input work for the first and second heat pumps if the second heat pump absorbs 20kW of heat and the heat release in the first heat pump is the same.
A refrigerator is used to keep the cold space at 5 °C by rejecting 8 kJ/s of heat by the condenser tothe outdoor air at 25 °C. If the compressor consumes 3 kJ/s of power, determinei. the rate of heat removed from the cold space (kJ/s),ii. the COP of the refrigeratoriii. the minimum power input to the compressor for the same rate of heat removed (kJ/s), andiv. draw the schematic of the refrigerator as a reversed heat engine.
An inventor draws 25000 kJ/h of heat from a heat well at -30°C, which requires 1.2 kW of power. He claims to have developed a refrigeration cycle that dumps heat into the heat source at 20°C. environment There is no other energy transfer with Evaluate this claim.
3.Two Carnot heat engines run in series with the efficiency of first engine is 1/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.
Since Lucas is an engineer familiar with thermodynamics. He decided to create his own heat engine at home to avoid paying for electricity. He created a small, makeshift heat engine for trial. The combustion of his fuel. diesel, reaches a temperature of 750°C, while waste heat is disposed to the atmosphere at 50°C. He, then connected a generator and a heat pump to the heat engine to check the amount of power being produced. Assume that the heat pump will be used to warm his room to 25°C, while the outside temperature is at 5°C. Lucas' rooms loses 85,000 kJ/hr of heat. And, 25% of the heat engine's power output goes to the heat pump. How much diesel (in kg) needs to be burned by the heat engine to maintain the temperature in Lucas' room? Assume carnot heat engine and heat pump. If the natural gas has a heating value of 22,000 BTU/lb.
An inventor claims to have a solar powered heat pump that receives energy as heat from the sun at the rate of 10 kW and extracts energy as heat from the environment at the rate of 7 kW. This system does not require any shaft or electrical power input. If you think this device is impossible, explain why using basic principles to support your argument. If you think it might be possible, what would be the steady-state rate of transfer of energy as heat to the house? (Assume TH = 20 Cand TL = -15 C).
A thermal machine operates between 2 tanks at 800ºC and 20ºC; half of the power produced by this machine is used to drive a fully reversible heat pump that absorbs heat from the cold environment at 2ºC and transfers it to a house that is maintained at 22ºC. If the house loses heat at a rate of 62,000 kJ/hr, determine the minimum heat flux that must be supplied to the heat engine in kJ/hr. show step by step a) 11,565.3 kJ/hra. b) 8,406.8 KJ/hra c) 3,158.5 KJ/hra d) 6,110.9 KJ/hra d) N.A.