Fabrication & testing of PCM impregnated drywalls for thermal energy storage

Abstract

[ACCESS RESTRICTED TO THE UNIVERSITY OF MISSOURI AT REQUEST OF AUTHOR.] This research illustrates the fabrication and thermal behavior of gypsum drywall containing phase change materials (PCMs), which could be used in the interior of a building envelope. The PCM used is a paraffin wax encapsulated in a polymer shell commonly known as microencapsulated PCM. The energy storing gypsum-PCM board has been characterized under simulated conditions for its thermal behavior in the thickness direction under various indoor and outdoor temperatures. Four different concentrations of PCM (7%, 12%, 20% and 25% W/W) were mixed in Gypsum to make board samples of 1-ft x 1-ft x 3/4-in and tested against a control board of gypsum with no PCM content. Thermal performance of PCM-gypsum boards was compared with the control board under the simulated summer conditions of about 93 degrees F outdoor temperature while the indoor conditions were about 67 degrees F. This research studies the effects of PCM-gypsum boards on energy savings by performing two test samples for every board; sample type 1 is where PCM-gypsum boards were tested against a control gypsum board with no PCM content, and Sample type 2 is a layered material of gypsum-1 in polystyrene and 0.5in wood backing where PCM-gypsum boards are tested against control board. A PCM-gypsum based Sample Type 2 was compared with one based in gypsum board only. Sample type 2 represents realistic wall structure. Under these conditions the temperature variation through the thickness of the gypsum board and heat flux in the thickness direction were measured. PCM-gypsum was a viable option for energy storage but needs better understanding of PCM behavior and its interaction with gypsum to further validate its schematics in building envelope.