PHASE-CHANGE FRAME WALLS (PCFWs) FOR ON-PEAK DEMAND REDUCTION AND ENERGY CONSERVATION IN RESIDENTIAL BUILDINGS: DEVELOPMENT, CONSTRUCTION, AND EVALUATION

The main purpose of this work was to develop a thermally enhanced frame wall that would reduce peak load air conditioning demand, shift a portion of the thermal load, and conserve energy in residential buildings. A frame wall containing macroencapsulated phase-change materials (PCMs), incorporated therein, was developed, constructed, and evaluated. This prototype wall is referred to as phase-change frame wall (PCFW). A PCFW is a typical frame wall, consisting of outside siding, thermal insulation, studs, and inside sheathing, in which PCMs are incorporated, by macroencapsulation, to enhance the energy storage capabilities of the wall, and thus thermal mass of the building, via the high latent heat of fusion of the PCMs. The PCFW uses off-the-shelf components, which are herein integrated in an innovative way to produce better energy performance. Results from field testing show that the PCFW offers the potential to reduce wall peak heat flux by as much as 38%. This value is dependent on climate, wall orientation, quantity of PCM, and wall insulation level. Over a period of days, the average wall peak heat flux reduction was approximately 15% when PCFWs facing four cardinal directions (i.e., N, S, E, W) were evaluated when 10% 1 concentration of PCM was used and approximately 9% when 20% PCM concentration was used. The average space-cooling load was reduced by approximately 8.6% when 10% PCM was applied and 10.8% when 20% was used. The level of fiberglass insulation in the PCFW was R-11 (1.94 m 2