International Journal for Research in Applied Science & Engineering Technology (IJRASET) ISSN: 2321-9653; IC Value: 45.98; SJ Impact Factor: 7.177 Volume 7 Issue XI, Nov 2019- Available at www.ijraset.com © IJRASET: All Rights are Reserved 904 Heat Transfer Enhancement during Flow Boiling of Refrigerant in Horizontal Copper tube Using Twisted Tapes Sumit Lade 1 , Dr. Ramakant Shrivastava 2 1 M.Tech. Student, 2 Head of Department, Dept. of Mechanical Engineering, Government college of Engineering Karad, INDIA Abstract: Heat transfer enhancement in the heat exchangers like evaporators, condensers and many more are considered as a stringent research issue in today’s energy crisis and associated economic, social and environmental concerns. In most of industrial heat exchangers, flow boiling or evaporation is the major phenomenon for different applications. Using R-407C as a refrigerant and Twisted tapes as passive techniques in modified evaporator section heat transfer enhancement is achieved. The heat flux values are varied here from 2-20 kW/m 2 and two distinct flow rates as 95 and 112 kg/m 3 s are taken to get the experimentation. This system gives efficient heat transfer enhancement values as well as lowering the chances of harming environment due to use of R-407C. Keywords: Flow Boiling, R-407C, Horizontal tube, Heat transfer, Refrigeration I. INTRODUCTION Extravagant use of energy by a human kind for his modern and luxurious life is creating energy crises, social issue as well environmental. Savings in conventional energy is now a big issue on research platform. Most of the conventional form of energy is consumed in converting to useful form of work, boilers, re-boilers etc. are the key components in heat exchange process to produce the desired effect, such as mechanical power, cooling or heating effect in refrigeration and air conditioning system. So, if heat transfer enhancement takes place effectively here, it will increase the performance of these heat exchangers and in turns will increase the efficiency of work producing system or heat actuated System. Twisted tapes are one of the passive techniques which includes surface geometries for heat transfer enhancement. It enhances the proper mixing of fluid and also avoids formation of laminar sub-layer which gives enhanced rate of heat transfer [1]. Also using R- 407C as a refrigerant helps in avoiding usage of R-22 which has higher GWP values as it shows comparatively less value of GWP and zero value od ODP. [2]-[4]. II. EXPERIEMENTAL SETUP Schematic layout of experimental setup of vapor compression system with all required accessories is shown in figure 2.1. For performing the investigation on heat transfer enhancement in evaporation of R-407C three major components are required m the vapor compression refrigeration system. These are: 1. Pre-Evaporator 2. Test-Evaporator 3. After-Evaporator. Pre-Evaporator can adjust the vapor quality of refrigerant at entry to the test-section of tube of Test-Evaporator. In Test-Evaporator, heat flux can be applied according to operating range and it has an arrangement to insert turbulent promoters in the test-section tube of heat transfer enhancement. After-evaporator can adjust the required super-heat of refrigerant at entry to compressor. In addition to the above arrangement. Hand shut-off valve can be used to vary the mass flux and evaporating pressure of refrigerant. Hence all that facilities proposed in the 1- Compressor.2- Condcnser.3- Drier 4- Sight glass 5-Oval gear flow meter 6-Thermostatic Expansion Valve 7-Pre-Evaporatow 8- Test-Evaporator 9-Aftcr-Evaporator 10-Fan 11-Accumulator 12-Shutoff valve 13-Heater rods 14-Submersible pump Fig 2.l Experimental setup