How can we simulate the Bi-directional flow and time-variant heat exchange ventilation system?

The aim of this study is to analyze the characteristics and performance of a Bi-directional flow and transient or variable heat exchange ventilator by experiment. In addition, a simulation method to describe the features of this system is proposed. The effect of the degree of simulation modeling for Bi-directional flow and transient or variable heat exchange ventilator on energy demand was analyzed by simulation. The adequacy of simulation modeling was verified in comparison with experimental results. The simulation results of time-variant heat exchange efficiency were in good agreement with the experimental results, within an error range of approximately 0.6%. The difference in energy consumption according to the degree of simulation modeling for Bi-directional flow and transient or variable heat exchange ventilator was found to be up to 22% according to the consideration of the energy consumption of the ventilator fan. There is no difference in simulation results between the method considering the time-variant heat exchange efficiency and the method of applying the time-averaged heat exchange efficiency. The consideration of air infiltration in the exhaust mode increased the heating energy consumed by approximately 5.4% but had little effect on the consumption of cooling energy. The results of this study will be helpful in determining the degree of simulation modeling for performance analyses of a Bi-directional flow and transient heat exchange ventilator.