Performance analysis of a refrigeration cycle using a direct contact evaporator

Abstract

This research work studies an ice thermal energy storage having an injection of R12 refrigerant into the water to exchange heat directly. The water temperature decreases to the freezing point and ice is formed. The ice is used for creating chilled water for an air‐conditioning purpose. The system consists of a compressor, a condenser, an expansion valve and a direct contact evaporator. This system has a capacity of approximately 2 tons of refrigeration. The system simulation created from the mathematical model of each component has been carried out. It was found that the performance of the system depends on two factors, the compressor speed and the mass flow rate of the refrigerant. The suitable conditions are 8–10 rps for the compressor speed and 0.04–0.06 kgs−1 for the mass flow rate. The coefficient of performance is about 3·4–3·6 which is higher than that of the conventional system. © 1998 John Wiley & Sons, Ltd.

Performance Analysis of Foam Ice Production System with Direct Contact Refrigerant Spraying in PCM Material Based on Dynamic Two-stage Refrigeration Cycle Driven by DPES

“…Table 5 showed that the main research results and was close to those of Kiatsirriroat et al [19,30], Sidemen [31] and Blair [32]. It was obvious that the volumetric heat transfer coefficient of refrigerant droplets h v of R22 and R134a in this paper were similar to results of Kiatsirriroat.…”

“…Therefore, in order to improve the refrigeration efficiency, the refrigeration technology of direct contact heat transfer is proposed, which is that the refrigerant is sprayed into cold storage material and the heat transfer is efficient without intermediate thermal resistance [14][15][16][17]. When R12 was employed as the refrigerant, the heat transfers between R12 and water was close to 100% and the system COP was about 3.4-3.6 [18,19], which was almost about 2-3 times that of coil evaporator ice making system. Because direct contact heat transfer keeps in contact with immiscible continuous liquid without intermediate thermal resistance, which is widely used in many industrial fields, such as industrial energy recovery and thermal energy storage for the advantages of relatively simple design, high heat transfer coefficient and no installation.…”

“…So the flow of ice slurry was smaller and the power consumed was lower. Moreover, the ice slurry has a lower flower resistance and larger heat transfer coefficient than cold water [19]. There are six methods to generate ice slurry such as moving bed, super-cooling, scraped surface heat exchanger, evaporative super-cooling, vacuum ice making and direct contact heat transfer.…”