Effect of Simulation methodology on variable efficiency of Bi-directional Heat Recovery Ventilator

Recently, Energy Recovery Ventilator (ERV) has been installed to secure energy saving and Indoor Air Quality (IAQ) in multi-residential building. A lot of effort has been devoted to the development of various types of ERV systems for the purpose of improving heat exchange efficiency, preventing condensation problems in the elements, and increasing usability etc. Among various ERV systems, a ventilation system using a new concept called Alternating Ventilation (AC ventilation) such as Bidirectional Heat Recovery Ventilator (BdHRV) has been developed and broadly installed. The performance of a heat (sensitive / latent / enthalpy) recovery ventilators are defined as a fixed value by measurement under specified indoor and outdoor conditions, and this value used as input data for the energy simulation. However, the heat exchange efficiency of Bi-directional Heat Recovery Ventilator (BdHRV) in which air supply and exhaust process are repeated over a period of time and heat is accumulated in the exhaust mode through the heat storage element and heat is released in the supply process is not constant but varies with time. In this study, the transient heat exchange efficiency of BdHRV was measured with test chamber measurement. The simulation method considering the transient heat exchange characteristics of BdHRV has been proposed. The effect of ventilation with BdHRV on heating/cooling energy usage are analyzed.