DESIGN AND FABRICATION OF A PORTABLE REFRIGERATOR BASED ON PELTIER EFFECT

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1 International Journal of Mechanical Engineering and Technology (IJMET) Volume 9, Issue 6, June 2018, pp , Article ID: IJMET_09_06_028 Available online at ISSN Print: and ISSN Online: IAEME Publication Scopus Indexed DESIGN AND FABRICATION OF A PORTABLE REFRIGERATOR BASED ON PELTIER EFFECT N. Lavanya, R.E Ravalika and V. Dharani Assistant Professor, Department of Mechanical Engineering, GPREC - Kurnool, Andhra Pradesh, India ABSTRACT In the present work an attempt has been made to design, fabricate and experimentally investigate the coefficient of performance of a portable refrigerator based on peltier effect. Experiments were performed to find the performance of two peltier modules that have been used namely TEC and TEC It is observed that among these two peltier modules, the performance of the TEC is better when compared with the TEC The performances of these two peltier modules are compared based on their COP and its heat removal capacity. Key words: wall jet; mean velocities; decay rate; Turbulence model. Cite this Article: Prasant Nanda, S.V.H. Nagendra and D.V.S. Bhagavanulu, Numerical Modeling of Wall Bound Flow for Thermal Comfort, International Journal of Mechanical Engineering and Technology 9(6), 2018, pp INTRODUCTION Portable Refrigerator is widely used because it is simple in design, and easy to fabricate, easy to maintain and it required cheap material for construction. The main problem with these systems is low coefficient of performance. Some researchers [10-13] have used thermoelectric materials as cooling devices. Many researchers [1 4] have used in two ways both heating as well as cooling. Owning to increase energy crisis more research work is going on in increasing the human comforts. In order to balance the energy and human comfort present work is done. The design and fabrication of the portable refrigerator system is done. In the present work an attempt has been made to improve the human comfort by having a portable refrigerator for storing the medicine, bottles, chocolates etc and simultaneously in addition we can have hand air cooler if a fan is attached and multiple peltier devices are used. 2. EXPERIMENTAL SETUP A portable refrigerator was constructed of fibre glass and the Volume of the cooling cabin mm 3 of size 150*150*250 mm as shown in figure 1. Battery is connected to supply the voltage. Thermocol is properly insulated to reduce heat losses. As shown in photograph editor@iaeme.com

2 Design and Fabrication of a Portable Refrigerator Based on Peltier Effect Experiments were conducted in the Heat Transfer laboratory of gprec Kurnool AP, India in the month of March. A cooling fan is used to force the air in the system. The flow rate is controlled by battery. To dissipate the heat an aluminum fin is used. The thermoelectric module is the device which works on the peltier effect. So this device is also called as peltier module. It contains hot side and cold side. Among the two, cold side is used for refrigeration process. The models we have used for refrigeration are TEC and TEC The temperature at the different points of the system is measured by a thermocouple. Figure 1 Shows the photograph of the experimental setup Peltier Effect: The Peltier effect refers to the absorption of heat into one end of a thermoelectric material and the release of heat from the opposite end due to a current flow through the material. The thermoelectric effect is the direct conversion of temperature differences to electric voltage and vice versa. A thermoelectric device creates voltage when there is a different temperature on each side. Conversely when a voltage is applied to it, it creates a temperature difference. There are different types of peltier devices available in the Market. But we have used two among those types of modules basing on their capacity and availability. Those two models are TEC TEC The specification of the name of the peltier device is coded as below: editor@iaeme.com

3 N. Lavanya, R.E Ravalika and V. Dharani 3. THEORETICAL ANALYSIS 1. The amount of heat transferred from the cabin to the atmosphere i.e., heat absorbed by the cold side of the peltier device is given by Q L = [SIT C 1/2 I 2 R K (T H - T C )] (-) sign for heat rejection. 2. The amount of heat transferred from hot side to the heatsink i.e., heat rejected by the heatsink to the atmosphere is given by Q H = SIT H + 1/2 I 2 R K (T H - T C ) 3. Seebeck coefficient (S) and electrical resistance (R) in Ohms are dependent both on the materials used within the TEC, but also on the geometry of the device, given by the number and dimensions of the individual N and P-type semiconductor elements. Where S = seebeck coefficient I = current T C = cold side temperature T H = hot side temperature R = electric resistance K = thermal conductivity Q L, Q H = heat absorbed and heat rejected respectively. 4. Specifications of TEC modules: Both of these models consist of bismuth telluride semi-conductors. The properties of these modules are as mentioned below. Seebeck coefficient(s) = V/K (Volts per Kelvin) Module thermal conductance (K) = W/K Module resistance(r) = 4Ω 5. Heat absorbed by the peltier module on cold side: Q L = [SIT C 1/2 I 2 R K (T H - T C )] Heat rejected by the peltier module on the hot side: Q H = SIT H + 1/2 I 2 R K (T H - T C ) 6. Total Energy Supply: The total energy supplied to the peltier module will be calculated by knowing the heat absorbed and the heat rejected. The total energy supplied is equal to the difference of the heat rejected and the heat absorbed. W = Q H - Q L Where W = total energy supplied 7. Cop calculations: A non-dimensionless parameter called the Coefficient of Performance is therefore used to measure the performance of a cooling machine. COP is the ratio of the thermal output power and the electrical input power of the TEC. COP can be calculated by dividing the amount of heat absorbed at the cold side to the input power. COP = Q L / Energy supplied (W) editor@iaeme.com

4 Design and Fabrication of a Portable Refrigerator Based on Peltier Effect 4. CALCULATIONS For TEC Heat absorbed by the peltier module on cold side: Q L = [SIT C 1/2 I 2 R K (T H - T C )] TC = C = K TH = 63 0 C = 336 K I = 2A TH - TC = C QL = ( *2*290.9) (0.5*4*4) (45.1) = J 2. Heat rejected by the peltier module on the hot side: QH = [SIT H + 1/2 I 2 R K (T H - T C )] QH = ( *2*336) + (0.5*4*4) (45.1) = 8.07 J 3. Total Energy Supply: W = Q H - Q L W = 8.07 (-9.03) = 17.1 J 4. Cop calculations: COP = Q L / Energy supplied (W) = 9.03 / 17.1 = RESULTS AND DISCUSSIONS The peltier module of model TEC has a COP value of and whereas the model TEC has a COP value has The temperature reduced using the TEC is less compared to the TEC The thermoelectric modules take much time to cool the cabin temperature. By increasing the voltages as well as the current the performance of the device will increases drastically but we should make sure that the maximum voltage and the maximum current should not be more than its rated supply of voltage and current. From the plotted graphs, we can say that the temperature and the time have almost linear relationship. FOR TEC Graph 1 Temperature distribution of the TEC editor@iaeme.com

5 N. Lavanya, R.E Ravalika and V. Dharani The lowest temperature we can obtain from this device is 19.6 o C was observed after a time period of 7 hours for a peltier module TEC FOR TEC Graph.2 Temperature distribution of the TEC The lowest temperature we can obtain from this device is 18.2 o C was observed after a time period of 6 hours for a peltier module TEC Comparison of the both the peltier modules are shown in the following graph: Graph 3 Comparison of TEC and TEC CONCLUSIONS Thermoelectric technology has been used practically in wide areas in recent times. The thermoelectric devices can act as power generators, thermal energy sensors /coolers and are used in almost all the fields such as military, instruments, medicines, biology and industrial or commercial products. The conclusions we obtained from this experiment are: The peltier module of model TEC has a COP value of and whereas the model TEC has a COP value has From the comparison of COP values of both the peltier modules, the TEC has more cooling capacity i.e % greater than the TEC editor@iaeme.com

6 Design and Fabrication of a Portable Refrigerator Based on Peltier Effect The lowest temperature we can obtain from a peltier module TEC is 18.2 o C was observed after a time period of 6 hours when compare to a peltier module TEC was observed after a time period of 7 hours is only 19.6 o C. The thermoelectric devices used in this project are single staged peltier modules. In the market, multi-stage peltier modules are also available. By using these multi-staged devices, there is a definite chance of increment in the COP. But these multi-staged devices are high cost as compared to the single staged devices. Hence, these peltier modules will have a good scope in the future in usage of many applications. REFERENCES [1] Elcosnier W., Gilles M., Lingai., An experimental and numerical study of a thermoelectric air-cooling and air-heating system. International journal of refrigeration, 31, , (2008). [2] Sujin.,Vora and Seetawan., Analyzing of thermoelectric refrigerator performance. Proceedings of the 2nd international science, social-science, engineering and energy conference, 25, , (2000). [3] Wei, Jinzhi., Jingxin., theoretical and experimental investigation on a thermoelectric cooling and heating system driven by solar. Applied energy, 107, 89-97, (2013). [4] Riffat and Guoquan., comparative investigation of air-conditioners verses vapour compression and absorption air-conditioners. Journal of applied thermal engineering, 24, , (2004). [5] Riffat and Qiu., Design and characterization of a cylindrical water cooled heat sink for thermoelectric air-conditioners. International journal of energy research, 30, 67-80, (2005). [6] Astrain D., Viran J.G., & Dominguez M., Increase of COP in the thermoelectric refrigeration by the optimization of heat dissipation. Applied thermal engineering, 23, , (2003). [7] Shen., Xiao., Chen & Wang., Investigation of a novel thermoelectric radiant airconditioning system. Journal of energy and buildings, 59, , (2012). [8] Virjoghe, Diana, Marcel & Florin., Numerical simulation of thermoelectric system. Latest trends on systems, 15(2), , (2009). [9] Maneewan, Tipsaenpromand Lertithanakorn., Thermal comfort study of a compact thermoelectric air-conditioner. Journal of electronic materials, 39(9), , (2010). [10] Manoj S., & Walke., Thermoelectric air cooling for cars. International journal of engineering science and technology,40(5), ,(2011). [11] Ydav and Nirves., Review on thermoelectric materials and applications. International journal for scientific research & development, 1, , (2013). [12] Manoj Kumar., Chattopadhyay and Neogi., A review on developments of thermoelectric refrigeration and air conditioning systems: a novel potential green refrigeration and air conditioning technology. International jornal of emerging technology and advanced engineering, 38, , (2013). [13] Huang B., Chin C.J., and Duang C.L., A design method of thermoelectric cooler, international journal of refrigeration, 23, (1999) editor@iaeme.com