All ETDs from UAB

Advisory Committee Chair

Hessam Taherian

Advisory Committee Members

Roy P Koomullil

David L Littlefield

Document Type


Date of Award


Degree Name by School

Master of Science in Mechanical Engineering (MSME) School of Engineering


Trigeneration systems, also known as Combined Cooling, Heating, and Power (CCHP), simultaneously provide electric, mechanical, and thermal energy. Compared to traditional systems, they deliver higher fuel efficiencies as waste heat from engine coolant and/or exhaust is recovered and utilized. In heating, ventilation, and air condi-tioning (HVAC) systems, the recycled heat may be used to provide space heating, water heating, and cooling (through absorption chillers). As there are more practical applica-tions for the recovered heat during the heating season than the cooling season, trigenera-tion systems tend to be more attractive in colder weather. This research focuses on the PowerAire 65 by M-Trigen trigeneration solution in a daycare facility in Birmingham, Alabama. The PowerAire system relies on a natural gas-fired reciprocating internal combustion engine to generate electricity and space cooling (by providing mechanical energy to a heat pump compressor). Additionally, heat recovered from the engine ex-haust system and the refrigeration line produces hot water. Currently, the CCHP unit operates under the same control parameters regardless of location. The daycare facility and trigeneration system were computer-simulated to eval-uate the performance. A novel approach was used for the calibration of a baseline mod-el. The simulation results were used to optimize control parameters in the unit. Three main conclusions were drawn: First, utility rates and weather conditions in Alabama do not promote the use of trigeneration systems such as PowerAire 65, as they are more expensive to operate than traditional HVAC appliances. Exceptions could be made in buildings with significant hot water demand during the cooling season. Second, trigeneration systems can be at-tractive in climate zones similar to Alabama, if the utility rate environment is appropri-ate. Third, although lower temperatures benefit the performance of trigeneration units against traditional HVAC systems, trigeneration systems are still not encouraged in cold regions if the utility rate environment is not adequate.

Included in

Engineering Commons



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