The main objective of the present work is to evaluate the potentials of the installed existing units of gas turbines for combined production of cooling, heating, power, and process heat. For this purpose a CCHPP cycle is proposed and simulated thermodynamically. The thermodynamical model is enriched with technical data extracted from the data sheets and operational manual and data of the gas turbine. The thermodynamic, economic, and environmental criteria of the CCHPP cycle are evaluated and impact of different parameters on these criteria is evaluated. For instant the impact of remaining lifetime of the gas turbine, ambient temperature, altitude, relative humidity, interest rate, and currency exchange value is investigated. In the economical valuations the conventional payback period is modified and a new formula that is more conservative is proposed. The results prove that fuel saving of more than 30% is achievable. Based on average consumption of natural gas in Iran, the amount of fuel saved can feed about 2450 and 5720 families in cold and hot climates respectively. The economical results show that for 1USD invested, about 0.5USD profit is achieved. Life analysis shows that for the existing gas turbines the minimum required life time for gas turbine to make the CCHPP investment profitable is about 15 years. Moreover the analyses show that the cycle characteristics are more sensitive to ambient temperature than relative humidity and altitude. The CO2, CO and NOx reduction of more than 52000, 36 and 44 tons per year is estimated when using CCHPP.
