Investigation on air flow patterns of evaporative cooling and dehumidification process for a hybrid refrigeration system

• Air flow patterns for refrigerant subcooling are studied in a hybrid system.
• Close-pattern and open-pattern are achieved based on ambient air ratios Ramb (0-1).
• Open-pattern (Ramb = 0.3) is suggested under typical climate condition.
• Close-pattern (Ramb = 0) is proposed under extremely humid climate condition.
• Maximum COPimp 12.3% is obtained and optimum working parameters are suggested.

In this paper, two different air flow patterns (close-pattern and open-pattern) are studied to achieve the optimum configurations of a hybrid refrigeration system, in which the refrigerant is subcooled by evaporative cooling of dry air dehumidified by the liquid desiccant. With different ambient air ratios (Ramb), full return air (Ramb = 0) is used in the close-pattern; full ambient air (Ramb = 1) and mix air (0 < Ramb < 1) are chosen in the open-pattern respectively. Comparisons of the close-pattern and open-pattern are made under typical climate condition and extremely humid climate condition. Both of the close-pattern and open-pattern (Ramb = 1) show much higher COP than the traditional refrigeration system, with the maximum COP improvement 12.3% and 9.8%, respectively. Under typical climate condition, the open-pattern (Ramb = 0.3) is suggested, the regenerator size has little influence on the system performance and the optimum mass flow ratio of ambient air to solution (ṁamb/ṁs) is between 0.5 and 2 in the regenerator; under extremely humid climate condition, the close-pattern is proposed, the optimum ṁamb/ṁs is 0.4 and larger regenerator size is suggested. In addition, the latent and sensible heat capacities in the indirect evaporative cooler are illustrated. These findings will be beneficial for the system design and optimization.