An enthalpy exchange element (EEE) is frequently made of papers, and a concern exists on growth of fungus or bacteria. This concern may be eliminated if polymer membrane is used instead of paper. Furthermore, most existing enthalpy exchangers have cross-flow configuration, which yields lower performance than counter-flow one. In this study, a counter-flow enthalpy exchange element was made using PVDF and cellulose composite. Heat and moisture transfer tests were conducted changing the frontal air flow rate from 150 m 3 /h to 350 m 3 /h at both the heating and the cooling condition. Results showed that the temperature efficiencies were approximately the same independent of the weather condition. Humidity efficiencies at the heating condition, however, were higher than those at the cooling condition. Furthermore, the heat transfer coefficients approached the theoretical value as the flow rate increased. In addition, the vapor transmission rates at the heating condition were higher than those at the cooling condition, probably due to the higher humidity efficiency at the heating condition. Future research will be focused on moisture diffusion characteristics of the composite membrane, which requires further measurements of water holdup, equilibrium adsorption curve, etc.

PURPOSES : A finite difference model considering snow melting process on porous asphalt pavement was derived on the basis of heat transfer and mass transfer theories. The derived model can be applied to predict the region where black-ice develops, as well as to predict temperature profile of pavement systems where a de-icing system is installed. In addition, the model can be used to determined the minimum energy required to melt the ice formed on the pavement. METHODS : The snow on the porous asphalt pavement, whose porosity must be considered in thermal analysis, is divided into several layers such as dry snow layer, saturated snow layer, water+pavement surface, pavement surface, and sublayer. The mass balance and heat balance equations are derived to describe conductive, convective, radiative, and latent transfer of heat and mass in each layer. The finite differential method is used to implement the derived equations, boundary conditions, and the testing method to determine the thermal properties are suggested for each layer. RESULTS: The finite differential equations that describe the icing and deicing on pavements are derived, and we have presented them in our work. The framework to develop a temperature-forecasting model is successfully created. CONCLUSIONS : We conclude by successfully creating framework for the finite difference model based on the heat and mass transfer theories. To complete implementation, laboratory tests required to be performed.