Energy, exergy and economic analysis of a combined power and subzero cooling cycle using ammonia absorption refrigeration system

• A cycle for power and subzero cooling using gas engine waste heat is proposed. • The proposed system generates electricity instead of consuming it. • The desired system prevents damage to the ozone layer by not using CFCs. • The cycle is simulated with a focus on using effectiveness coefficients. • Energy efficiency is 26.24%, exergy efficiency is 29.29%, and payback is 4.53 years. A lesser-known application of cogeneration systems is the combined production of subzero cooling and electricity for industrial purposes like cold storage using absorption refrigeration. Traditional cooling generation methods, such as compression refrigeration systems, are energy-intensive, costly, and harmful to the ozone layer due to the use of chlorofluorocarbons. This study introduces a novel cogeneration system as an alternative to compression refrigeration, focusing on the utilization of cogeneration systems and ammonia absorption refrigeration for industries such as cold storage. The proposed system significantly prevents ozone layer damage by utilizing ammonia-water as the working pair. Also, this proposal uses excess heat from a gas engine to meet an industrial complex's cooling needs while generating electricity. Thus, the system not only avoids consuming electricity for cooling generation but also turns industries like cold storage into power generators. Unlike earlier research, this system is simulated with a focus on using the effectiveness factors of heat exchangers and assessed through energy, exergy, and economic criteria. The study also examines how key input factors affect system efficiency and the necessary surface area for heat exchangers. The simulation results indicate that achieving 100 TR of cooling requires 2833.5 kW of input energy, which, alongside fully meeting the cooling demand, also 391.54 kW of electricity is generated. Energy efficiency is calculated at 26.24%, while exergy efficiency reaches 29.29%. The average implementation cost and net present value are $2.72 million and $10.30 million, respectively. Additionally, the average payback period is estimated 4.53 years.