Modeling air-to-air plate-fin heat exchanger without dehumidification

In heating, ventilation and air-conditioning (HVAC) systems, air-to-air plate-fin heat exchangers (PFHEs) can be used as heat recovery devices to reduce the building energy consumption. However, existing heat exchanger models have limitations in simulating the performance of air-to-air PFHEs. For example, some models adopt heat transfer correlations which are not suitable for PFHEs, while others require detailed geometric data which are usually difficult to access, etc. To address these limitations, we developed a new model for air-to-air PFHE without dehumidification. Based on empirical correlations dedicated to air-to-air PFHEs, the mathematical models of the heat transfer and the flow resistance were built. The new model considers the impacts of the changing air flow rates and temperatures. Additionally, it only requires readily available nominal parameters as inputs and does not need any geometric data. Furthermore, no numerical discretization is needed to solve the equations, which makes the model computationally more efficient than models using the finite-element method. To evaluate the performance of the new model, it is implemented using an object-oriented, equation-based modeling language Modelica. Case studies show that the new model can predict the results with a relative deviation less than 10% compared to the experimental data.