Abstract

A frost-free membrane energy exchanger design model is developed combining the conventional ε−NTU method with a frost limit model. A concept of plate performance index is defined to evaluate the net energy saving ability. The frost-free design model and plate performance index are employed for a case study of single-family dwelling with an all-fresh-air air handling unit with a heat/energy recovery exchanger. The membrane energy exchanger, which is able to ensure frost-free operation without extra frost control strategies, is applicable to most cold climates for residential applications. The membrane energy exchanger has a significant energy saving potential compared to conventional plate heat exchangers. Preheating rather than enlarging the energy transfer area is recommended for severe cold climates.

ABSTRACT

Space-heating using wood stove is a popular solution in many European countries. Nevertheless, nominal powers of state-of-the-art stoves are oversized compared to the needs of highly-insulated building envelopes, such as passive houses. In this respect, a simplified wood stove model has been developed in order to investigate the thermal comfort using detailed dynamic simulations (e.g. TRNSYS) at an acceptable computational cost. A specific experimental setup has been developed to validate this modelling procedure, especially as regards the interaction between the stove and the building. The largest source of error appears to be the thermal stratification in the room where the stove is placed. This can simultaneously affect the conductive heat transfer between rooms, the thermal comfort sensation in the room as well as the convective heat exchange by flows through doorways. Nonetheless, the present work proposes a correction to circumvent this last effect. Finally, thermal comfort measurements during the experimental campaign confirm the conclusions of previous simulation results (Georges, Skreiberg, & Novakovic, 2014), supporting their proposed guidelines for the integration of wood stoves in passive houses.