Thermo-environ-economic evaluation of a trigeneration system based on thermoelectric generator, two-bed adsorption chiller, and polymer exchange membrane fuel cell

In the present article, a cycle is proposed for combined production of cooling, heating and electricity. A polymer exchange membrane fuel cell is used as the prime mover. The waste heat is recovered by a plate heat exchanger, and the hot water is used as the heat source of a two-bed adsorption chiller, and heating as well. In addition, the excess hot and chilled water are used to generate electricity in thermoelectric generator. To feed the thermoelectric generator with a steady temperature hot/cold-thermal damping tanks are proposed and a procedure is developed to design them. The mathematical models of the fuel cell, adsorption chiller, and thermoelectric generator are validated with the results of other researchers. Detail design information is provided for the plate heat exchanger, hot/cold-thermal damping tanks, and fins of the sink/source sides of the thermoelectric generator. Parametric and sensitivity analyses are presented for four design parameters. The sensitivity analysis showed that overall efficiency is most/least sensitive to the current density/number of thermoelectric modules. For normal operating conditions the overall energy/exergy efficiencies are 75% and 53%. In comparison with the conventional systems the fuel energy saving ratio is 39% and 16.9 tons/year less carbon dioxide is produced. In addition, the for hydrogen price of less than 2 United States dollars per kilogram the CCHP can compete with conventional systems.