does a heat engine reject some heat to a lower temperature resorvoir

Solutions

Expert Solution

Yes, any heat engine rejects some heat to the lower temperature reservoir.

Consider the ideal engine (Carnot engine). From a high temperature reservoir at temperature . the engine obtains amount of heat. The engine does amount of work by converting a part of this energy to work. And the engine rejects the remaining amount of energy to a lower temperature reservoir at temperature .

Efficiency of this engine

If the engine is not rejecting some heat to the lower temperature reservoir, then , that is .

Hence efficiency

But there is no Carnot heat engine with this efficiency as implies that . But absolute zero is not attainable.

Real heat engines have efficiency less than that of Carnot engine. Hence they also cannot attain the temperature of absolute zero.

Hence all engines must reject some heat to the lower temperature reservoir.

genius_generous answered 1 year ago

Next > < Previous

Related Solutions

Consider a heat engine that is 40% efficient and operating with a furnace at a temperature...

Consider a heat engine that is 40% efficient and operating with a furnace at a temperature of 727oC with a cooling reservoir at 27oC •A. If the heat engine withdraws 1MJ/s from the furnace, what is the rate of entropy loss from the furnace? • •B. What would be the rate of entropy gain in the cold reservoir? • •C. What is the total entropy gain of the system? D. Do A , B, and C again with zero efficiency...

A heat engine operates between a high-temperature reservoir at 610 K and a low-temperature reservoir at...

A heat engine operates between a high-temperature reservoir at 610 K and a low-temperature reservoir at 320 K. In one cycle, the engine absorbs 6800 J of heat from the high-temperature reservoir and does 2200 J of work. A) What is the net change in entropy as a result of this cycle?

A Carnot engine uses air as the working substance, receives heat at a temperature of 315oC,...

A Carnot engine uses air as the working substance, receives heat at a temperature of 315oC, and rejects it at 65oC. The maximum possible cycle pressure is 6.0MPa and the minimum volume is 0.95 liters. When heat is added, the volume increases by 250%. Determine the pressure and volume at each state in the cycle.

How do the condensers reject heat?

How much total heat transfer is necessary to lower the temperature of 0.295 kg of steam...

How much total heat transfer is necessary to lower the temperature of 0.295 kg of steam from 145.5 C to -23.5 C, including the energy for phase changes. How much time is required for each stage of this process, assuming a constant 835.0 W rate of heat exchange? Give the times in the order that the stages occur. T1 = T2 = T3 = T4 = T5 =

How much total heat transfer is necessary to lower the temperature of 0.315 kg0.315 kg of...

How much total heat transfer is necessary to lower the temperature of 0.315 kg0.315 kg of steam from 145.5 °C145.5 °C to −15.5 °C,−15.5 °C, including the energy for phase changes? total heat transfer: JJ How much time is required for each stage of this process, assuming a constant 835.0 W835.0 W rate of heat exchange? Give the times in the order that the stages occur. t1=t1= ss t2=t2= ss t3=t3= ss t4=t4= ss t5=t5= ss Question Credit: OpenStax College...

How much total heat transfer is necessary to lower the temperature of 0.275 kg of steam...

How much total heat transfer is necessary to lower the temperature of 0.275 kg of steam from 145.5 °C to −15.5 °C, including the energy for phase changes? total heat transfer: J How much time is required for each stage of this process, assuming a constant 815.0 W rate of heat exchange? Give the times in the order that the stages occur. t1= t2= t3= t4= t5=

A Carnot heat engine operates between temperature levels of 600 K and 300 K with 8...

A Carnot heat engine operates between temperature levels of 600 K and 300 K with 8 MW heat transferred in the boiler. It drives a compressor, which compresses steam from 200 kPa, 200°C to 1 MPa, 500°C. If mass flow rate of the steam is 5 kg/s. determine the following: (a) The power output of the heat engine (kW). (b) The power input of the compressor (kW). (c) The efficiency of the compressor.

When adding heat to a substance at its phase transition temperature, why does the temperature of...

When adding heat to a substance at its phase transition temperature, why does the temperature of the substance not change? What is the energy used for?

As speed increases in an engine with throttle body fuel injection, does the temperature of the...

As speed increases in an engine with throttle body fuel injection, does the temperature of the air-fuel mixture at the intake manifold exit increase or decrease? Explain what parameters affect your answer.

Subjects