What is the coefficient of performance of the refrigerator?
The coefficient of performance, COP, of a refrigerator is defined as the heat removed from the cold reservoir Qcold, (i.e. inside a refrigerator) divided by the work W done to remove the heat (i.e. the work done by the compressor).
How do you calculate the cooling effect of a refrigerator?
In the gas cycle, the refrigeration effect is equal to the product of the specific heat of the gas and the rise in temperature of the gas in the low temperature side. Therefore, for the same cooling load, gas refrigeration cycle machines require a larger mass flow rate, which in turn increases their size.
What is the coefficient of performance K of the Carnot refrigerator?
Chegg.com. Prove that the coefficient of performance of a Carnot refrigerator is K carnot = T c /(T H − T c ).
How do you calculate maximum thermal efficiency?
The thermal efficiency is a dimensionless unit. If you take formulas in thermodynamics, you can get that η= 1- (T COLD/THOT). TCOLD usually represents the ambient temperature where the engine is located. This may just be the temperature outside in whatever environment the engine is at.
What is the formula of thermal efficiency?
quantities are heat-equivalent values. So, for a boiler that produces 210 kW (or 700,000 BTU/h) output for each 300 kW (or 1,000,000 BTU/h) heat-equivalent input, its thermal efficiency is 210/300 = 0.70, or 70%. This means that 30% of the energy is lost to the environment.
Why 100 efficiency is impossible?
It is impossible for heat engines to achieve 100% thermal efficiency () according to the Second law of thermodynamics. This is impossible because some waste heat is always produced produced in a heat engine, shown in Figure 1 by the term.
Which machine has highest efficiency?
The most efficient electrical machine is the transformer. Transformers have efficiency above 95%. The autotransformer has an efficiency of close to 98%. The maximum efficiency is achieved under the fully loaded condition.
What is the Carnot cycle used for?
Carnot cycle, in heat engines, ideal cyclical sequence of changes of pressures and temperatures of a fluid, such as a gas used in an engine, conceived early in the 19th century by the French engineer Sadi Carnot. It is used as a standard of performance of all heat engines operating between a high and a low temperature.
What is ideal gas cycle?
Ideal cycles are simplified thermodynamic closed cycles to analyze the compression, combustion, and expansion process in an engine with a focus on extraction of work from combustion of the fuel–air mixture.
What are the four steps in Carnot engine?
Name the processes involved in Carnot cycle? It involves four process: isothermal expansion, adiabatic expansion, isothermal compression and adiabatic compression.
What are the corollaries of Carnot theorem?
Corollary 1 of Carnot’s Theorem: The first Corollary of Carnot’s theorem can be stated as follows: All reversible heat engines operating between the same two heat reservoirs must have the same efficiency.
What are two essential features of Carnot’s ideal heat engine?
Answer. 1-It should have a source of infinite thermal capacity. 2-It should have a sink of infinite thermal capacity.
How do you calculate Carnot efficiency?
efficiency =WQH=1−TCTH. These temperatures are of course in degrees Kelvin, so for example the efficiency of a Carnot engine having a hot reservoir of boiling water and a cold reservoir ice cold water will be 1−(273/373)=0.27, just over a quarter of the heat energy is transformed into useful work.