Because the coefficient of performance cop is primarily concerned with the core refrigeration system, using it for optimisation purposes may lead to higher than necessary energy consumption. If the heat recovery system is designed optimally and implemented in residential and smallscale commercial systems, the cumulative benefits would be significant. Just like the efficiency of power cycles, the cop is defined as the ratio of the desired output to the required input. The effectiveness of refrigerators or air conditioners represents one way of comparing coefficient of performance as q c w in for q c the heat the refrigerator gives off q c and the work input to the system w in. Generalized performance characteristics of refrigeration. It explains how to calculate the mechanical work needed to transfer heat. This synopsis deals with experimental investigation by using r600 refrigerant and to calculate the value of cop. Refrigeration cycles the vapor compression refrigeration cycle is a common method for transferring heat from a low temperature to a high temperature. Therefore the condition of the refrigerant after compression is superheat. Refrigerators, heat pumps, and coefficient of perfomance. Then, we examine the influence of the damping coefficient on the propulsion performance of the foil, and notice the damping coefficient has a serious adverse effect on the output power and propulsion efficiency. Coefficient of performance of a refrigerator the coefficient of performance briefly written as c. Cop of alternative refrigerants must also be established.
Efficiency of a refrigeration system and heat pump is denoted as the coefficient of performance cop. Apparatus figure 1 shows the experimental setup in details. The coefficient of performance, cop, of a refrigerator is defined as the heat removed from the cold reservoir q cold, i. Pdf to study the coefficient of performance using different. Determine a the compressor power, in kw, b the refrigeration capacity, in tons, c the coefficient of performance. Yogesh parkhi associate professor department of mechanical engineering school of research and technology, bhopal doi. The purpose of a refrigerator is the removal of heat, called the cooling load, from a lowtemperature medium. Illustrating the relationship between the coefficient of performance.
The cop is known as the classical measure of refrigeration unit or heat pump thermal efficiency 6. Therefore, for the same cooling load, gas refrigeration cycle machines require a larger mass flow rate, which in turn increases their size. Vapor compression refrigeration cycle objective determining the coefficient of performance of a vapour compression refrigeration cycle. Coefficient of performance and relative coefficient of. If there is sub cooling in the condenser, h 1 can not be obtained from ph table note 3. For such activities a pro gramme is proposed to the iir working party on magnetic refrigeration. It can be seen that very little work has been done to compare the performance of refrigeration or air conditioning system under different power sources which is the motivation of our work that will compare the performance of absorption refrigeration under differ.
A method for reducing the coefficient of performance to a design value from measured temperature conditions of a vapor compression type refrigeration system of the type having series arranged compressor, condenser and evaporator units and an electric motor for driving said compressor unit, said system further having a condenser water supply line and evaporator chilled water supply and. The efficiency depends on the temperature difference. The symbol used for coefficient of performance is cop with a subscript r, for refrigeration. The potential forms of the performance factor include, but are not limited to, the energy efficiency ratio eer in btuhw, coefficient of performance cop in ww, and ratio of power input to capacity in bhpton. Coefficient of performance heat removed by refrigerant power input. It is also known as theoretical coefficient of performance. Refrigeration systems are also rated in terms of tons of refrigeration. One ton of refrigeration is equivalent to 12,000 btuhr or 211 kjmin. Because the coefficient of performance cop is primarily concerned with the core refrigeration system, using it for optimisation purposes may lead to higher than. Coefficient of performance refrigerator, air conditioner.
The effect of mass ratio and damping coefficient on the. Coefficient of performance cop is the efficiency ratio of the amount of heating or cooling provided by a heating or cooling unit to the energy consumed by the system. Comparison between heat engine, refrigerator, and heat. Comparative evaluation of different refrigerants on a. If the mass flow rate of the refrigeration through the upper cycle is 0. To improve the coefficient of performance cop, it is require decreasing the compressor work and increasing the refrigerating effect. There are two coefficients of performance for such a cycle, one for the refrigeration effect and one for the heat pump effect. For the case of no frictional dissipation terms, the expression of the coefficient of performance simplifies to where and the cooling rate is the coefficient of performance has a maximum at the point where this clearly approaches the carnot efficiency as the leak conductance, and thus, vanishes. The performance of refrigerators and heat pumps is expressed in terms of coefficient of performance cop. Introduction the performance of a simple vapour compression refrigeration system, used in numerous of small refrigeration applications all over the world, deteriorates in actual conditions due to. The refrigeration capacity and coefficient of performance. The coefficient of performance of a refrigerator is defined as the ratio of useful cooling effect provided by the refrigerator to the work required.
This demonstration is intended to illustrate the use of the pressureenthalpy diagram to calculate the energy efficiency of an ideal mechanical refrigeration system in terms of its coefficient of performance. This comparison of coefficient of performance helps in determining the best performing refrigerant in refrigeration industry. The ideal compression refrigeration cycle is not an internally reversible cycle. Pdf publications on magnetocaloric materials, magnetic refrigerators, magnetic heat pumps and magnetic power conversion machines. Coefficient of performance cop the coefficient of performance is used to measure the units efficiency while in the heating mode and is applied to heat pumps, of any nominal cooling capacity, that operates on three phase current. Pdf performance study of refrigeration units that use the. We have all experienced a sensation of heat when passing behind a functioning refrigerator or air conditioner.
Performance cop is studied by using different condenser. The reversed carnot cycle unlike the carnot heat engine, the carnot refrigeration cycle undergoes a process with opposite direction. The coefficient of performance is used to quantify the performance of refrigeration cycles. Us4768346a determining the coefficient of performance of. Mathematically theoretical coefficient of performance o f refrigeration is denoted as follows theoretical c. What is the maximum theoretical coefficient of performance. Refrigeration cycle coefficient of performance wolfram. Calculation of coefficient of performance in vapour compression refrigeration system by using r600 refrigerant umar farooque, mr. The higher the coefficient of performance the more efficient the system.
Calculation of coefficient of performance for refrigerant 404a. According to the second law of thermodynamics, the heat flow from a cold body to a hot body occur only by doing some outside work. Vapour compression refrigeration, transient, capillary tube, heat transfer coefficient, coefficient of performance 1. The energy output appears as useful heat at a higher temperature than the surroundings while the energy input is supplied by electricity or the direct use of fossil fuels. The coefficient of performance cop is a performance rating that tells us how effective a heat pump or air conditioner is at transfering heat versus the amount of electrical power it consumes. Coefficient of performance heat pump, refrigerator, air conditioner in general, the thermal efficiency. Coefficient of performance an overview sciencedirect. Refrigerators, air conditioners, and heat pumps heat cannot, of itself, flow from a cold to a hot object is one way of stating the second law of thermodynamics. The coefficient of performance, cop, of a heat pump is defined as the ratio of the energy output to the input.
Coefficient of performance article about coefficient of. On the other hand, the cop for the ideal cycle with 5. Sub cooling increases the cooling capacity and will prevent entering any vapor bubbles to the expansion valve. For ideal or non ideal conditions, h 3 can not be obtained from ph table for the above 3 conditions, use the ph diagram to determine the enthalpy value 7. Comparison of the performances of absorption refrigeration. Refrigeration is a process of eliminating heat from a low temperature reservoir and transferring it to a high temperature reservoir. Chapter 102 cop q w cop q w r l net in hp h net in desired output required input cooling effect work input desired output. The above figure shows the objectives of refrigerators and heat pumps. Coefficient of performance of a refrigerator engineering. What is the coefficient of performance of the carnot. Coefficient of performance of refrigeration the refrigerator is a device that extracts heat from colder part reservoir of the system and delivered it to the hotter sink environment.
The performance of refrigerators and heat pumps is expressed in terms of coefficient of performance cop, defined as. If it could, then heat dumped at t low could just flow back to the reservoir at t high and the net effect would be an amount of heat. Experimental analysis on vapour compression refrigeration vcr system with r4a tetra fluro ethane refrigerant. The coefficient of performance or cop sometimes cp or cop of a heat pump, refrigerator or.
Coefficient of performance enhancement of refrigeration. Despite a lower coefficient of performance cop as compared to the vapor compression cycle, absorption refrigeration systems are promising for using inexpensive waste energy from industrial processes, geothermal energy, solar energy etc. Remember, heat pumps and air conditioners move heat from a low temperature area, and pump this heat uphill to a high temperature area, and against the laws of. Qw where, q the total heat extracted in refrigeration amount of cooling effect. Im confused with this problem, any help would be greatly appreciated. Electrical heating for example has a coefficient of performance of 1. Improving the coefficient of performance of thermoelectric cooling systems. What is the cop coefficient of performance in hvac.
The cop is determined by the ratio between energy usage of the compressor and the amount of useful cooling at the evaporator for a refrigeration instalation or useful heat extracted from the condensor for a heat pump. 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. Aim of this paper is to im pr ove coefficient of performance of system. The coefficient of performance or cop sometimes cp or cop of a heat pump, refrigerator or air conditioning system is a ratio of useful heating or cooling provided to work required. Coefficient of performance maximum coefficient of performance actual coefficient of performance differences between theoretical and actual performance in particular, to achieve a rate of heat transfer sufficient to maintain the temperature of th. Performance factor shall be computed as a ratio of capacity to power input at specified operating conditions. The efficiency of refrigeration systems and heat pumps is denoted by its coefficient of performance cop. The coefficient of performance, cop, of a heat pump is defined as the ratio of the.
The net refrigeration capacity in tons shall be obtained by the following equation. This physics video tutorial explains how to calculate the coefficient of performance of refrigerators and heat pumps. Refrigeration cycle q c 8000 kjh the coefficient of performance b for the refrigeration cycle is given by b c c cycle q w cycle q w 8,000 kjh 3,200 kjh 2. The cop usually exceeds 1, especially in heat pumps, because. Performance of a refrigeration absorption cycle driven by. Pdf a standardization of the coefficient of performance for.
Coefficient of performance an overview sciencedirect topics. Energy performance assessment of hvac systems bureau of energy efficiency 116 the accurate temperature measurement is very vital in refrigeration and air conditioning and least count should be at least one decimal. The coefficient of performance or cop of a heat pump, refrigerator or air conditioning system is a ratio of useful heating or cooling provided to work required. Coefficient of performance the efficiency of refrigeration systems and heat pumps is denoted by its coefficient of performance cop. Coefficient of performance refrigeration example the coefficient of performance can take many forms that are unique to or inherently based on the principles of specific disciplines. We see from the model, heat ql is absorbed from the lowtemperature reservoir tlconstant and heat qh is rejected to a hightemperature reservoir thconstant. The coefficient of performance of refrigeration plant is given by the ratio of heat absorbed, by the refrigerant when passing through the evaporator or the system, to the working input to the compressor to compress the refrigeration. How to calculate coefficient of performance sciencing. Engineering thermodynamics and heat transfer experiment 2. Coefficient of performance for a refrigeration cycle. To evaluate a heat pumps efficiency while in cooling mode, eer or seer must be used.