Comparison of gas turbine and diesel engine in optimal design of CCHP plant integrated with multi-effect and reverse osmosis desalinations

The combined heating, cooling, power (CCHP) and freshwater system are designed separately with two types of desalination plants including multi-effect desalination with thermal vapor compression (MEDTVC) and reverse osmosis (RO). This combined system meets the heating, cooling, power and fresh water needs of a hotel in Iran. Gas turbines and diesel engines are considered as prime movers (PM) for conversion of fuel to power and heat. The integration of the CCHP system with RO desalination was investigated in two modes of RO without colloidal fouling (first day of operation) and with colloidal fouling formation rate in a period of 90 days. The genetic algorithm (GA) was implemented to find the optimal values of 21 design parameters in the case of CCHP system with RO desalination and 22 design parameters in the case of CCHP system with MED-TVC desalination to minimize the annual cost. Optimization results showed that the diesel engine prime mover has a greater advantage over the gas turbine in the all studied modes. In addition, combination of CCHP + RO without colloidal fouling and with colloidal fouling and combination of CCHP + MED-TVC with diesel engine as PM showed 9.66 %, 1.80 % and 11.68 % reduction in annual cost compared with gas turbine as PM, respectively. (c) 2021 Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.

Automated summary

This study investigated the integration of CCHP system with two types of desalination plants and optimized the design parameters to minimize annual cost. Results showed that diesel engine prime mover outperformed gas turbine in all studied modes, leading to significant reduction in annual cost. Combination of CCHP + RO and CCHP + MED-TVC with diesel engine as prime mover achieved notable cost reductions compared to using gas turbine as prime mover.