Technical and economic evaluation of the combined production cooling, heating, power, freshwater, and hydrogen (CCHPWH) system in the cold climate

Background

Multi-generation plant is a decentralized, energy-efficient method of different type of energy production. Such a system can deliver multiple benefits and advantages compared to conventional energy production such as improvement in the efficiency, emission, cost and reliability.

Methods

Technical-economic analysis of the combined cooling, heating, power, freshwater and hydrogen generation system (CCHPWH) are presented in this paper. Selecting the nominal power of prime movers, their numbers, the cooling capacity of absorption and electrical chillers, the heating capacity of auxiliary boiler, electric cooling ratio (the ratio of electrical chiller capacity to the cooling load demand), motive steam pressure, number of effects, motive steam flow rate, feed flow rate and 24 partial loads for the prime mover during in the year are considered as 35 design parameters. The optimization of the studied system was used by the genetic algorithm to obtain the minimum total annual cost (TAC) as an objective function. The total annual cost includes economic, energy and environmental parameters. It should be noted that selling/buying electricity to/from the grid is allowable in this study.

Significant findings

The optimum results showed 24.8% reduction in the total annual cost of the CCHPWH system using a gas engine as prime mover as compared with a gas turbine. In addition, the exergy efficiency of the cogeneration system in the optimal state for the prime mover of the gas turbine and the gas engine was obtained 31.21% and 45.58%, respectively. Finally, the optimal results in different cases were compared and results were discussed.