Hybrid-Cooling Combined Cooling, Heating and Power Systems;pp. 349-368
Authors: (Nelson Fumo, Mechanical Engineering Department, Mississippi State University, Mississippi)
Abstract: Combined cooling, heating, and power (CCHP) is a distributed generation technology that reduces the use of electricity from the grid by using low emission fuels such as natural gas. CCHP makes better use of fuels by using recovered heat to drive thermally activated components which results in high overall energy efficiency. CCHP systems are not only economically beneficial; these systems also conserve energy and reduce CO2 emission. Conventional CCHP systems are best utilized in buildings that have constant baseline electricity and thermal energy demand that would allow the system to consistently operate at maximum or near maximum efficiency. For example, because of their constant operation, hospitals have traditionally made excellent candidates for CCHP systems. For buildings with high daily and seasonal variation of energy demand, such as office buildings, mechanical systems will operate mainly at partial load. Because mechanical equipment efficiency decreases as consequence of partial load operation, a CCHP system is not always the soundest option. This chapter considers the incorporation of benefits from hybrid-cooling (using electric and nonelectric chillers) on a CCHP system to assess the potential benefits of a hybrid-cooling CCHP system over a traditional CCHP system. A model for the simulation of the hybridcooling CCHP system is developed and implemented for simulation with an hour time step. Results are presented as percentage reduction of primary energy consumption and carbon dioxide emission by using EnergyPlus Benchmark Models as reference buildings. The results show that hybrid-cooling CCHP systems decreases primary energy consumption and carbon dioxide emission when compared with the benchmark and standard CCHP system (having only an absorption chiller).