Two-phase heat transfer during refrigerant evaporation in a solar collector tube (CROSBI ID 519657)
Prilog sa skupa u zborniku | izvorni znanstveni rad | međunarodna recenzija
Podaci o odgovornosti
Soldo, Vladimir ; Grozdek, Marino ; Ćurko, Tonko
engleski
Two-phase heat transfer during refrigerant evaporation in a solar collector tube
The paper presents the calculation of heat transfer in a tube of the solar collector (evaporator) where the refrigerant R134a evaporates. The test system used consists of a compressor, a freon-water compact plate condenser, an electronic expansion valve and two parallel unglazed solar collectors. The solar-assisted heat pump with direct expansion of the refrigerant in the solar collector uses the solar irradiation and the ambient temperature as a heat source on the evaporator. The heat transfer in the two-phase flow of the refrigerant in a horizontal tube is expressed by the expressions taken over from the VDI Wärmeatlas. The effect of the mass velocity G (kg/(m2 s)), the heat flux based on the inner surface of the tube q (W/m2) and the vapour quality x on the heat transfer coefficient in the heat pump solar collector is recorded. Results of calculation have shown that the nucleate boiling is dominant in the first part of the evaporator-collector, while in the second part of the evaporator, with the increase in vapour quality, the convective evaporation prevails.
Heat transfer; evaporation; solar collector
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Podaci o prilogu
207-212-x.
2006.
objavljeno
Podaci o matičnoj publikaciji
61st ATI National Congress – ; International Session “ ; Solar Heating and Cooling” ; (Conference Proceedings)
University of Perugia
Perugia: Morlakija
Podaci o skupu
61st ATI National Congress – ; International Session “ ; Solar Heating and Cooling” ;
predavanje
14.09.2006-14.09.2006
Perugia, Italija