Experimental investigation of R290/R600a mixture as an alternative to R134a in a domestic refrigerator

Department of Mechanical Engineering, National Institute of Technology Calicut, Calicut 673601, India
International Journal of Thermal Sciences (Impact Factor: 2.63). 05/2009; 48(5):1036-1042. DOI: 10.1016/j.ijthermalsci.2008.08.001


R134a is the most widely used refrigerant in domestic refrigerators. It must be phased out soon according to Kyoto protocol due to its high global warming potential (GWP) of 1300. In the present work, an experimental investigation has been made with hydrocarbon refrigerant mixture (composed of R290 and R600a in the ratio of 45.2:54.8 by weight) as an alternative to R134a in a 200 l single evaporator domestic refrigerator. Continuous running tests were performed under different ambient temperatures (24, 28, 32, 38 and 43 °C), while cycling running (ON/OFF) tests were carried out only at 32 °C ambient temperature. The results showed that the hydrocarbon mixture has lower values of energy consumption; pull down time and ON time ratio by about 11.1%, 11.6% and 13.2%, respectively, with 3.25–3.6% higher coefficient of performance (COP). The discharge temperature of hydrocarbon mixture was found to be 8.5 to 13.4 K lower than that of R134a. The overall performance has proved that the above hydrocarbon refrigerant mixture could be the best long term alternative to phase out R134a.

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Available from: M. Mohanraj, Feb 04, 2015
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    • "A hydrocarbon blend of difluoromethane (R32), propane (R290) and iso-butane (R600a) is recommended to avoid the stratospheric ozone depletion. The presence of R600a in the mixture is miscible with both mineral oil and synthetic lubricants (Mohanraj et al,2009).The hydrocarbon mixture (R290 and R600a) in the ratio 45.2:54.8 by weight is investigated in the domestic refrigerator in which the COP is improved upto 3.6% and also reduce the indirect global warming due to its higher energy efficiency (Mohanraj et al,2009). The propane/iso-butane mixture at 0.6 mass fraction used as the refrigerant has a 3-4% higher energy efficiency and faster cooling rate. "
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    ABSTRACT: This paper explores an experimental investigation of an alternative eco-friendly refrigerant for R134a with a better Coefficient Of Performance (COP), reduced Global Warming Potential (GWP) and Ozone Depletion Potential(ODP). This investigation has been accessed using a hydrocarbon refrigerant mixture composing of R32/R600a/R290 in the ratio of 70:5:25 by weight. The performance characteristics of the domestic refrigerator were predicted using continuous running tests under different ambient temperatures and cyclic running (On/Off) tests at the fixed temperatures i.e., evaporation temperature (-5 ̊C) and condensation temperature (30 ̊C). The obtained results showed that the hydrocarbon mixture has lower values of energy consumption; pull down time and ON time ratio also higher Coefficient of Performance (COP). Thus, the performance of the alternate refrigerant derives the better choice than R134a
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    • "Thermodynamic properties of R134a are good but the global warming potential (GWP) is 1430 which is quite high considering the human health and environmental norms. Keeping in view the GWP of R134a, it is an urgent need to find the alternative refrigerants [1] [2]. As per latest European norms, the refrigerants which are having GWP more than 150 cannot be used in the automobile air conditioning systems [3]. "
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    • "Since the latent heat of hydrocarbons is much higher than that of R134a, the amount of refrigerant charge can be reduced. An experimental investigation was conducted by Mohanraj et al. [12] using a hydrocarbon mixture consisting of propane and isobutane with a ratio of 45.2:54.8 by weight as a replacement for R134a in a domestic refrigerator. The results showed that this hydrocarbon mixture leads to a reduction in the compressor energy consumption, pull down time, 1 and ON time ratio 2 by 11.1%, 11.6% and 13.2%, respectively. "
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    ABSTRACT: This paper is devoted to feasibility study of substitution of two hydrocarbon refrigerants instead of R134a in a domestic refrigerator. Experiments are designed on a refrigerator manufactured for 105 g R134a charge. The effect of parameters including refrigerant type, refrigerant charge and compressor type are investigated. This research is conducted using R436A (mixture of 46% iso-butane and 54% propane) and R600a (pure iso-butane) as hydrocarbon refrigerants, HFC type compressor (designed for R134a) and HC type compressor (designed for R600a). The results show that for HFC type compressor, the optimum refrigerant charges are 60 g and 55 g for R436A and R600a, respectively. Moreover, for this type of compressor, the energy consumption of R436A and R600a at the optimum charges is reduced about 14% and 7%, respectively in comparison to R134a. On the other hand, when using HC type compressor, the optimum refrigerant charges for R436A and R600a are both 50 g, and the energy consumption of R436A and R600a at the optimum charges are reduced about 14.6% and 18.7%, respectively. Furthermore, when the refrigerator is equipped with HC type compressor, working under optimum charges of R436A and R600a have a total equivalent warming impact about 16% and 21% lower than base refrigerator, respectively. Total exergy destruction of the domestic refrigerator with HFC type compressor for R134a, R600a and R436A are 0.0389, 0.0301, 0.0471, respectively and for R600a and R436A with HC type compressor are 0.0292, 0.0472, respectively.
    International Journal of Thermal Sciences 12/2013; 74:86-94. DOI:10.1016/j.ijthermalsci.2013.07.009 · 2.63 Impact Factor
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