Testing and simulation of phase change wallboard for thermal storage in buildings: Fid-Bau Portal

Testing and simulation of phase change wallboard for thermal storage in buildings

Kissock, J.K. / Hannig, J.M. / Whitney, T.I. / Drake, M.L.

When linear alkyl hydrocarbons are formulated to change phase at near room temperature and are impregnated into gypsum wallboard, they can store large amounts of heat over the narrow range of temperatures typically encountered in buildings. This dampening effect could improve thermal comfort in interior spaces, delay the need for cooling until off-peak hours, and reduce the required size of mechanical cooling and heating equipment. This paper summarizes an experimental and simulation study of the thermal performance of phase-change wallboard (PCW) in simple structures. Two 1.22 m (4 ft.) x 1.22 m (4 ft.) x 0.61 m (2 ft.) test cells were constructed using common light-frame construction practices. One wall of each test cell consisted of a transparent acrylic sheet to allow solar radiation to penetrate the cell. The cells were oriented so that the glazing faced south. Conventional wallboard was installed in the control test cell, and wallboard imbibed to 30% by weight with K18 phase-change material was installed in the second test cell. A differential scanning calorimeter (DSC) test measured the effective heat capacities of both the PCW and conventional wallboard. Solar radiation, ambient temperature and interior temperatures in the test cells were continuously monitored from 10/28/97 to 11/10/97. Results indicated that peak temperatures in the phase-change test cell were up to (10 degree C) 18 degree F less than in the control test cell during sunny days. A modified finite-difference simulation model was able to predict interior wall temperatures in the test cells with reasonable accuracy (average error <1.7 degree C (3 degree F)) based on measured property and environmental data.