Journal of Material Science and Mechanical Engineering (JMSME) p-ISSN: 2393-9095; e-ISSN: 2393-9109; Volume 2, Issue 13; October-December, 2015 pp. 66-70 © Krishi Sanskriti Publications http://www.krishisanskriti.org/Publication.html An Experimental Investigation and Performance Evaluation of VCRS system by Varying Mass Flow Rate and Ambient Temperature of Refrigerants R-12 and R-134a Taliv Hussain 1 , Sameen Mustafa 2 , Akeel Ahmed 3 , Afroj Ali 4 and Sohail Anwer 5 1 Department of Mechanical Engineering, Aligarh Muslim University, Aligarh 2,3,4,5 Student, Department of Mechanical Engineering, Aligarh Muslim University, Aligarh E-mail: 1 talivamu@gmail.com, 2 sameenmustafa4@gmail.com Abstract—From a long time improving COP of vapour compression refrigeration system and optimising its performance has been a major challenge for the engineers. Now we are trying to solve the problem by capacity modulation (variable refrigerant flow) technique. In this paper we worked on two different refrigerants at two different ambient temperatures, one being 25 ° C and the other 30°C. The first refrigerant was R-12 and the second was R-134a. Each of the refrigrants had two different mass flow rates as 0.0028kg/s and 0.0053kg/s. For R-12 the COP was found to be 2.66 and 2.19 at ambient temperatures of 25 ° C and 30 ° C respectively corresponding to mass flow rate of .0028 kg/sec. Similarly the COP was found to be 3.30 and 2.64 at ambient temperatures of 25 ° C and 30 ° C respectively for mass flow rate of .0053 kg/sec. For refrigerant R-134a the COP was found to be 2.30 and 1.93 at ambient temperatures 25 ° C and 30 ° C respectively corresponding to flow mass rate .0028 kg/sec. Similarly the COP was found to be 2.72 and 2.43 at ambient temperatures 25 ° C and 30 ° C respectively for mass flow rate .0053kg/sec. Hence it was observed that the COP increased with increasing the mass flow rate of the refrigerant. Also, at the same mass flow rate and same ambient temperature COP of R- 12 was found to be better than COP of R-134a. Keyword: Vapour Compression Refrigeration System, variable refrigerant flow rate, air cooled condenser, COP, refrigerants (R-12 & R-134a). 1. INTRODUCTION Refrigeration is the science of producing and maintaining temperatures below that of the surrounding atmosphere, this means removing of heat from a substance which is to be cooled. Refrigeration or air conditioning is a kind of heat pump whose function is to remove heat from a lower temperature. Out of all refrigeration systems the vapour compression refrigeration system (VCRS) from the view point of commercial and domestic utility, it is the most practical form of refrigeration. In this paper we are using two different refrigerants R-12 and R-134a. Here, we are mainly focusing on flow rate of refrigerants, by controlling the mass flow rate (capacity modulation technique) we are trying to enhance the performance of VCRS system and reducing the power consumption. Nowadays capacity modulation technique is emerging trend in the air conditioning industry for both residential and commercial application. There are two technologies that can provide capacity modulation inverter and digital scroll. For R-12 with the increase in refrigerant mass flow rate, there is increase in COP of about 24%. And for R-134a with the increase in refrigerant mass flow rate there is increase in COP of about 18% which further decreases the power consumption. Wang and Hihara (2003) [1] proposed an equivalent dry-bulb temperature (EDT) method to analyse the cooling and dehumidifying performance of refrigeration and air- conditioning systems. This method could predict the totally dry, wet and partially wet cooling modes. The simulation model was validated by experimental data and the deviation was found to be within 10%. Ma et al (2005) [2] conducted the experiments and developed a correlation to predict the mass flow co-efficient for the flow of refrigerantsR22, R407C and R410A through EEVs of six different geometries made of copper. By choosing the parameters such as EEV head geometry, EEV inlet conditions, EEV outlet conditions and refrigerant properties and using Buckingham pi Theorem, the correlations for the refrigerant mass flow coefficient (CD) for EEV was predicted. The performance of the EEVs with several half taper and inner diameter combinations for R22 and its alternatives R407C and R 410 A were experimentally investigated. The mass flow rates of R407C are greater by 4.25 %, and those of R410A are greater by 22.70 % on average, than those of R22. R410A