Experimental Investigation To Develop The Refrigeration System With Two Phases Condensing Ejector Along With Energy Saving

Vapour compression cycles are used in refrigeration, space cooling and space heating applications. Typical vapour compression cycles involve compressing and decompressing a refrigerant in a closed loop system and circulating the refrigerant through an evaporator and a condenser. The refrigerant serves to absorb thermal energy in the form of heat from the evaporator and transport the thermal energy to the condenser where it can be released. In refrigeration and cooling applications heat is absorbed from a space by the refrigerant during an evaporation portion of the cycle where the refrigerant changes into a vapour phase. The absorption of heat provides useful cooling of the space. The vapour is subsequently compressed in a compressor. Energy is consumed by the compressor during the compression of the vapour. Compression of the vapour facilitates condensation of the vapour into a liquid. Condensation of the vapour is caused by flowing the compressed vapour through a condenser where heat is released into a heat sink thereby condensing the refrigerant into a liquid. The liquid is circulated through the closed loop to a decompression device, typically an expansion valve and capillary tube where the pressure of the refrigerant is decreased. Typically, the refrigerant pressure is reduced by a factor of five or more. The decompressed refrigerant is returned to the evaporator resuming the cycle. The investigation of a new cycle for vapor compression refrigeration with using a novel device for non - mechanical compression of refrigerants, called a “condensing ejector” was carried out within this project. The condensing ejector is a two-phase jet device in which a subcooled homogeneous working medium in a liquid state is mixed with its vapor phase, producing a liquid stream with a pressure that is higher than the pressure of either of the two inlet streams. The mixing takes place first in a convergent section and then in a constant area section of the ejector device. There is a large temperature difference and a high relative velocity between both streams, which results in a high rate of a heat and momentum transfer. The vapor phase is quickly condensed onto the liquid stream, producing rapid transformation from two-phase into single-phase flow with a resulting rise in pressure, called “a condensation shock.” While a theoretical basis for the condensing ejector principle has been reasonably established in the past, only two practical applications have been reported—for underwater propulsion and liquid metal MHD power generation (Miguel et al., 1964) .The first theoretical principles of the ejector as reported by Bohdal et al. (2003) in his state-of-the art presentation were elaborated by Parsons (1911) while the first prototype was built by Leblanc (1910) . Further improvements were introduced by Gay (1931). Ejectors were first applied for refrigeration cycles by Heller (1955) for absorption systems and by Badylkes (1958) for vapor compression systems. In the USA, the first application was reported by Kemper (1966), but only the patent is in existence while no experimental or theoretical background has been published. Following up on this early work, a theoretical analysis was conducted, showing the potential efficiency improvement of 21% when compared with a standard vapor compression cycle (Kornhauser, 1990).