With is more when the ambient temperature is high.

With the help of Sub cooling, the refrigeration effect and efficiency of the system increases. M.Zubair(2013) has done a experiment on vapour compression refrigeration system with and without sub cooling for a low size systems. By sub cooling the power consumption of the system increases with increase in the cooling capacity. The sub cooling has done by using the heat exchangers by flowing the fluid in the sub cooler and refrigerant in the condenser. The authors has compared the sub cooling effect with respect to different timings in the day and concluded that the sub cooling effect is more when the ambient temperature is high. Akintunde(2013) has done a experimental study on the blending of eco friendly refrigerants which are alternatives for R12. He has done the experiment on mixing of various ecofriendly refrigerants like R600a,R134a,R406a in various proportions. From the experiment it came to know that the cop will increase up to certain refrigerant charge for maximum effectiveness. But when compared the cop with respect to R12, The relative COP remains constant irrespective of refrigerant charge. M.rasti(2011) has done the experiment on the eco friendly refrigerants and compared with widely used refrigerant R134a. He analysis the refrigerants performance by passing them through the refrigerator. By keeping four different temperatures of freezer and refrigerant air temperature and from the results, for high temperature freezer and refrigerant air temperature yields low energy consumption. Also, the refrigerant charge and inlet evaporator temperature for eco friendly refrigerants are less when compared to R134a. M.abuzar qureshi(2011) has studied about the performance of domestic refrigeration system with the help of R134a and R600 refrigerants under steady state condition. Analysis has done by keeping the constant evaporator temperature. They have checked the energy consumption by keeping the bulbs in parallel and series condition. The cop of the system is more when the energy consumption of the bulbs is less. Global warming potential of R1234yf has less than that of currently using refrigerators, Reasor(2010)  has investigated about the thermo physical properties of R1234yf with comparison of R134a and R410 assuming that they used in vapour compression system with same input temperature and cooling load with the help of tube fin heat exchangers and micro channel heat exchangers. They have developed a simple thermodynamic model and determine the mass flow rates and pressures of each refrigerant and the analysis is made by using vapour compression simulation software. Results have shown that both R134a and R1234yf has similar output for same cooling temperature and load. However the properties may differ from different designs of heat exchangers. With the new technology developed and considering the energy saving shuanshi jan(2017) has developed a hydrate based refrigeration system. Using methyl fluoride, cyclopentane, and water are used as a working fluid in the system. Three different type of inversions are done by using the hydrate disassociation tank and hydrate formation tank. The maximum COP occurs when the  hydrate disassociation tank work as a evaporator and hydrate formation tank as a condenser and heat from the gas and liquid release separately from the system. The system performs 3 to 4times better than conventional refrigeration system