An analysis of the periodic counterflow heat exchanger for air-to-air heat recovery ventilators

Abstract

The proper operation of the ventilation system under very low external air temperature is still a great challenge. Due to the icing of the ventilation unit, maintaining appropriate air parameters in rooms during the winter period typically requires additional external energy for the devices. In this research work, a unique system with a periodic counterflow heat exchanger was presented. The proposed system characterized by a high efficiency of heat and moisture recovery operates continuously, regardless of the prevailing external weather conditions. An experimental and numerical analysis of the periodic counterflow heat exchanger for air-to-air heat recovery ventilators was carried out to verify and determine the key parameters of the system operation. It has been shown that simple modification of a typical counterflow heat exchanger allows moisture recovery from the extract air. The developed model of the proposed solution allowed for a detailed analysis of the operation of the system depending on weather conditions. As a result of the simulations, the impact of the temperature, velocity, and humidity of fresh and extract air on heat and moisture recovery efficiency was determined.