UC Davis

IECs (Indirect Evaporative Coolers) have emerged as a promising cooling technology due to their lower energy consumption and carbon footprint, improved efficiency, and a zero GWP alternative by avoiding the usage of refrigerants. The purpose of this research is to assess the thermal performance of an HMX (Heat and Mass Exchanger) in the form of an IEC developed by Seeley International . Indirect evaporative coolers (IEC) cool the primary air without adding humidity to the indoor environment by using the latent heat of vaporization of water in the secondary air stream. By pre-cooling the secondary air stream before extracting heat in cross-flow with the primary air, the Maisotsenko Cycle (M-Cycle) design of an IEC has the ability to approach dew-point temperatures. A sectional mathematical model was developed by linking the heat and mass transfer equations in discretized control volumes and solved in Engineering Equation Solver (F-Chart Inc.). Results from the model were validated using experimental data from lab experiments for conditions with no condensation on the primary side. The simulation findings were found to be in good agreement with the experimental data, with an error of less than 10% in the primary exit temperatures and secondary outlet humidity ratios; and less than 8% in the secondary exit temperatures. The mean average errors (MAE) reported for the primary outlet temperatures, secondary outlet temperatures and humidity ratios were 0.78 C, 1.22 C and 0.0007 respectively. A parametric study was also carried out to evaluate the effects of some factors on the performance of the IEC, namely air flow rates, primary and secondary side channel lengths and heights, separation plate thickness and plate conductivity. Results concluded that the maximum impact on the performance parameters (dew-point and wet-bulb effectiveness and heat transferred) was exhibited by primary side air flow rate, channel lengths and heights of both primary and secondary side. The study corroborates the potential of IECs as a feasible cooling device besides suggesting the optimum design parameters.