PITA FY2014 Projects

Use of Phase Change Materials for the Energy Recovery of HVAC Systems in Green Buildings

PI:S.C. Yao, Mechanical Engineering

University:Carnegie Mellon University

Co-PI(s):Dale Clifford, Civil and Environmental Engineering

Industry Affiliate(s):DMI Companies

Summary:The HVAC systems of buildings are the major energy users in US. The buildings require significant fresh air intakes from the ambient, which needs pre-heating or pre-cooling during winter or summer times respectively. For the saving of energy, the air pre-conditioning could be accomplished with the exhaust air from the building using phase change materials. At winter time, the phase change material embedded in an array of tube bundles can absorb the heat from the exhausting room air. After the phase change occurs, the cold intake air will run through this bundle, absorbing the released heat and warm up before entering the HVAC system. Another set of identical bundle is used simultaneously in opposite phase of the air in/out cycle. With a butterfly valve, the in and out air streams flow alternatively between the two bundles.

The project will include the conceptual design, laboratory testing, and numerical modeling conducted at CMU. While the system design and product testing will be conducted at DMI Companies. The advanced system with air side and PCM side heat transfer enhancements, the hybrid of several PCM materials with different phase change temperatures among the tubes, the real condition modeling and testing, sensing and control, and the system optimization will be established. The DMI is a leading HVAC duct system manufacturer and is ready to distribute this new PCM system into the market after this project is completed.