International Engineering Research Journal Performance assessment of multistage thermoelectric cooling module based refrigerator

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1 International Engineering Research Journal Performance assessment of multistage thermoelectric cooling module based refrigerator RohitKasnale A, VirendraBhojwani B A Department of Mechanical Engineering, JSCOE, S.P.Pune University, Maharashtra, India ( rohitkasnale999@gmail.com) B Department of Mechanical Engineering, JSCOE, S.P.Pune University, Maharashtra, India ( Bhojwanivk@gmail.com) Abstract The main objective of this study is to design and build refrigerator based on thermoelectric modules. The refrigerator could be used to store perishable items and facilitate the transportation of medicine as well as biological materials. The design is based on peltier effect to create hot side and cold side. The cold side is used for refrigeration purpose and hot side is for rejection of heat to the atmosphere. Multistage TEC refrigerator gives larger temperature difference in source and sink than single stage. The designed refrigerator was experimentally tested for cooling process the results indicated the temperature of the refrigerator was reduced from 30 ( C) to 5 ( C). in approximately 1 hour. Keywords:Peltier effect, thermoelectric module, multistage refrigerator. 1. Introduction Thermoelectric devices are used in cooling applications to pump heat. To date, thermoelectric technology has been constrained to applications that include vehicle waste-heat recovery prototypes, space vehicle power sources, seat coolers, solid-state refrigerators, and temperature control in laboratory equipment. development of better materials and their potential to improve the efficiency of Improvements in material performance are ongoing since conversion efficiencies of typical thermo-electric materials remain below 10%. Thermoelectric refrigerator sometimes called a thermoelectric cooler module or Peltier cooler is a semi-conductor based electric component that functions as a small heat pump. By applying a low voltage current (DC) power to a thermoelectric module, heat will be moved through the module from one side to the other. One module face, therefore, will be cooled while the opposite face simultaneously is heated. Both thermoelectric refrigerators and mechanical refrigerators are governed by the same fundamental laws of thermodynamics and both refrigeration systems; although considerably different in form, function in accordance with the same principles. In a mechanical refrigeration unit, a compressor raises the pressure of a refrigerant and circulates the refrigerant through the system. In the refrigerated chamber, the refrigerant boils and in the process of changing to a vapor, the refrigerant absorbs heat causing the chamber to become cold. The heat absorbed in the chamber is moved to the condenser where it is transferred to the environment from the condensing refrigerant. In a thermoelectric cooling system, a doped semi-conductor material essentially takes the place of the refrigerant, the condenser is replaced by a finned heat sink, and the compressor is replaced by a Direct Current (DC) power source. The application of Direct Current to the thermoelectric cooler modules causes electrons to move through the material. At the cold end of the semi-conductor material, heat is absorbed by the electron movement, moved through the material, and expelled at the hot end. Since the hot end of the material is attached to a heat sink, the heat is passed from the material to sink and then in turn, transferred to the environment. The peltier module was discovered by a French watchmaker during the 19th century. It is described as a solid state method of heat transfer generated primarily through the use of dissimilar semiconductor material (P-type and N-type). Previously, thermoelectric devices were used in for medical devices, sensor technology, on heat removal, waste heat and maximum system temperature difference for a specified DC voltage and applied current. Another important characteristic of peltier module is the polarity of the heat removal changes when the direction of applied current changes, thus it is potential to cool or warm an object within same configuration, with respect to the polarity of the current. When considering usage of these peltier modules, it is necessary to analyze the performance of

2 the module over the heat removal rate. From a manufacturer data sheet of peltier module known as TE Technology, Inc, It is necessary to maintain the system temperature difference with respect to required heat removal in order to maintain the COP performance of the peltier module. 2. Design of TEC Module based refrigerator In this proposed work, the main aim is to develop a refrigeration system with a capacity of 35L of cooling chamber. It is necessary to design a system capable of maintaining the temperature of the materials between desired range. Since the system has to be used in remote areas where power is scarce, alternative sources of energy like battery or solar power has to be incorporated in the design. Moreover the system is meant for outdoor use which makes better insulation and radiation control mandatory. In order to meet worse scenario, even though the system is to designed for maintaining a fixed chamber temperature throughout the operational period, the design should be such that it can adaptable for refrigerating the chamber from ambient temperature to the required temperature. Fig 2.Experimental setup of TEC refrigerator 3. Cabinet Development As Fig 2 illustrates all the components as connected together in testing the operation of thermoelectric module. The red wire of the thermoelectric module was connected to the positive power supply and the black wire is connected to the negative power supply. Due to this connection the back side of the TEC module becomes cold and front side becomes hot side. Fig.3 Refrigerated cabinet It is made of structural steel 304. The overall dimension of the cabinet are 350*350*350mm. In the designed thermoelectric refrigerator 8 thermoelectric modules were used on either side of the cabinet. in addition to 8 small heat sinks are used one for each module. These fans are used to cool the fins and reject the extra heat to ambient surroundings. TEC Selection The experimental setup consist of the thermoelectric modules, designed cabinet for refrigeration,fans for cooling, thermocouple,temperature indicator,power supply regulator. The TEC module was selected by considering few factors such as dimensions, power supply etc. The model number of the module is TEC It is decided to select a TEC module which has a cooling power greater than the calculated cooling load. TEC operates with an optimum voltage value of 12V. It has a maximum voltage of 15.4V. At 12V it draws and maximum DC current of A. The nominal power rating or the cooling power is 0 W. It has a maximum operating temperature of C. ΔΤ of the TEC is 8 when hot side temperature is 25 0 C. It had been

3 decided to choose TECs of the same model so that when the power of all the TEC modules are greater than the calculated cooling load. The minimum power rating for TEC modules added together was more than the cooling load calculated. More number of TEC reduces the time required for cooling of a particular material. Product TEC-1270 Operational voltage 12V DC Current max AMP Voltage max 15.4V Power nominal 0 Dimension 40*40*3.5mm Fig fan arrangement for cooling. Results and Discussion Table.1 Readings for single stage TEC module These are the results obtained from single stage thermoelectric modules. Fig 4 TEC module NO VOLTAGE TEMP TEMP TIME T (V) COLD HOT SIDE (MIN) SIDE Fig 5 TEC module setup

4 time International Engineering Research Journal NO VOLT TEMP TEMP TIME T AGE (V) COLD HOT SIDE MIN SIDE Fig. 5 Graph of voltage vs time for multi stage TEC module Conclusion We have been successful in designing a system that fulfils the proposed goals. The present design can be used only for light heat load to lower its temperature to a particular temperature. This is one of the advantageous project which uses low power to drive Table.2 Readings for multistage TEC module refrigerator. The TEC cold plate temperature inside TER using single stage modules was reduced from 30( C) to 5( C) in approximately 30 min and in multistage TEC module it is reduced to same temperature 30( C) to time 5( C) in 1 min approximately. As we can observe the graph for multistage TEC module, the temperature 35 drop is very fast compared to single stage. We can say that performance of multistage TEC module is better 30 than the single stage modules in same operating conditions time Fig. 4 Graph of voltage vs time for single stage TEC module References voltage 1. Ajitkumar N. Nikam, Dr. Jitendra A. Hole (2014) A Review On Use Of Peltier Effects, Pratibha: International Journal of Science, Spirituality, Business and Technology (IJSSBT), Vol. 2, No. 2, ISSN (Print) Anthony M. Pettes, Marc S. Hodes, Kenneth E. Goodson (2007) Optimized Thermoelectric Refrigeration In The Presence Of Thermal Boundary Resistance, IPACK Brooks Samuel Mann (200) Transverse Thermoelectric Effects For Cooling And Heat Flux Sensing, Blacksburg, Virginia

5 4. D. Astrain a, J.G. Vian, M. Domınguez (2003) Increase Of Cop In The Thermoelectric Refrigeration By The Optimization Of Heat Dissipation, Applied Thermal Engineering 23 (2003) Onoroh Francis, Chukuneke Jeremiah Lekwuwa, Itoje Harrison John (2013) Performance Evaluation Of A Thermoelectric Refrigerator, ISSN: ISO 9001:2008 Certified International Journal of Engineering and Innovative Technology (IJEIT) Volume 2, Issue 7. Rahul S. Chavan, ManojDhawde (2015) Review On Performance And Analysis Of Thermoelectric Cooling In Various Applications, IJARSE Volume No. 04, Issue V.Rajangam, M.Vekataramanan (2015) Design And Cfd Analysis Of Thermoelectric Cooling System, International Conference On Recent Advancement In Mechanical Engineering &Technology, ISSN: Y.J. Dai, R.Z. Wang, L. Ni (2002) Experimental Investigation On A Thermoelectric Refrigerator Driven By Solar Cells, Renewable Energy 28 (2003) HoSung Lee (2013) Optimal design of thermoelectric devices with diamentional analysis.