Cooling capacity of experimental system with natural refrigerant circulation and condenser radiative cooling

Abstract

The surface of the Earth is a source of radiation of thermal energy, which, passing through the atmosphere, is partially absorbed while the bulk of the energy is released into the surrounding outer space. A cooling technique based on this physical phenomenon is known as radiative cooling (RC). It is possible to reduce the consumption of electricity for cooling, as well as to reduce capital costs, by integrating the unit with radiative cooling directly into the circulation circuit of the refrigerant of the refrigeration machine. An experimental refrigeration system has been designed, in which in the cold periods of the year the removal of heat from the cooled object is carried out due to the mode of natural circulation of the refrigerant from the evaporator to the heat exchanger, cooled by radiative cooling. A refrigeration system with natural circulation and radiative cooling of the refrigerant R134a was experimentally studied during the autumn period in Almaty. The experimental study established that the chamber is cooled with the help of the examined system while the temperature in the cooled volume is maintained by 5...7 K above ambient air temperature at night. The dependence of the air temperature in the refrigerating chamber on the temperature of the atmospheric air has been determined. A procedure for assessing the cooling capacity of the system has been devised. The study reported here demonstrated the possibility of using radiative cooling to remove heat under the mode of natural circulation of the refrigerant. The refrigeration system reduces energy consumption in the cold seasons by diverting heat to the environment without the compressor operating

Condensation heat removal due to the combined impact of natural convection and radiative cooling

“…To exclude intermediate coolant circuits, a refrigeration system was previously proposed, in which cooling occurs due to the natural circulation of the coolant through the radiators [11]. The study showed that such a system can work without consuming electricity.…”

“…where ΔtMC.N -the average temperature pressure on the radiat ing surface, determined under the condition that the entire radiating surface has the same temperature. Substituted expression (11) into formula (12), and also assumed that t t t…”