Experimental investigation of R290/R600a mixture as an alternative to R134a in a domestic refrigerator
ABSTRACT 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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ABSTRACT: Vapour compression refrigeration is used in almost 80 % of the refrigeration industries in the world for refrigeration, heating, ventilating and air conditioning. The high-grade energy consumption of these devices is very high and the working substance creates environmental problems due to environmental unfriendly refrigerants such as chloroflurocarbons, hydrochloroflurocarbons and hydroflurocarbons. Heating, ventilating, air conditioning and refrigeration industries are searching for ways to increase performance, durability of equipments and energy efficiency in a sustainable way while reducing the cost of manufacturing. With the present refrigerants, environmental problems such as ozone layer depletion, global warming potential, green house gases and carbon emission are increasing day by day. In this paper, the popular refrigerant is thoroughly studied experimentally and recommendations are given for alternatives such as carbon dioxide, ammonia and hydrocarbons and new artificially created fluid, Hydro-Fluoro-Olefin 1234yf by DuPont and Honeywell which exhibit good thermo-physical and environmental properties and will be commercialized in the near future.International journal of Environmental Science and Technology 10(4). · 1.84 Impact Factor
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ABSTRACT: This paper deals with a powder-feeding device using hollow cylindrical piezoelectric ceramics; the device is constructed so that the hollow cylindrical piezoceramics itself acts as an electrical excitation part as well as a powder-feeding part, and therefore its specific merits are small size and simple construction. Characteristics of the powder-feeding device are measured by changing the length of the silicone rubber cover as a guide for the powder supply or the electrode width for electrical excitation. The measured characteristics are compared with calculated characteristics, as to the propagated ultrasound wave number and elliptic motion of displacements of an infinite hollow cylinder.Japanese Journal of Applied Physics 01/1993; 32:2405-2407. · 1.07 Impact Factor