Maisotsenko cycle based counter and cross flow heat and mass exchanger: A computational study

Abstract

Maisotsenko Cycle (M-Cycle) is a recently patented and novel thermodynamic cycle which utilizes the renewable latent heat of evaporation of humid air to attain a temperature below the wet-bulb. In contrast, existing evaporative cooling methods can only cool an air to around its wet-bulb temperature. However, the modification in an indirect evaporative cooler has enabled to obtain a temperature below its wet bulb temperature, and towards its dew point temperature. Two types of heat and mass exchangers (HMXes) are under extensive research for air conditioning applications specifically based on M-Cycle applications, namely, counter and cross-flow HMXes. In this research paper, a comparative performance study of both heat exchangers is presented based on their cooling effectiveness, Coefficient of Performance (COP), and cooling capacity. For both types of HMX, balances of mass, momentum and energy are computed. The resulting coupled ordinary differential equations with coupled boundary conditions are discretized using first order accurate finite difference numerical formulation. The governing equations are simulated using purposely developed code. Validation is obtained by comparing the predicted results with experimental studies of HMX in both flow configurations. Results are presented by varying ambient temperature, humidity, and flow rate. It is concluded that a cross flow HMX is more viable for commercial use because of its ease of construction and higher COP values, whereas, a counter flow HMX offers more cooling effectiveness.