ISSN オンライン: 2688-7231
ISBN オンライン: 978-1-56700-524-0
Proceedings of the 26thNational and 4th International ISHMT-ASTFE Heat and Mass Transfer Conference December 17-20, 2021, IIT Madras, Chennai-600036, Tamil Nadu, India
Waste Heat Recovery of A Diesel Engine Exhaust by A Combined Power and Cooling System Comprising of Reheat Organic Rankine Cycle and Absorption Refrigerator
Waste heat recovery systems are very crucial means to satisfy the growing demand of energy in recent times. These systems are operated by absorbing the heat rejected by certain mechanical systems operating at higher temperature, and generate useful energy in the form of work or heating or cooling. In this paper, a cogeneration system has been developed to generate electrical power and refrigeration. The proposed cogeneration system, powered by the heat rejected from a diesel engine exhaust, is comprised of a reheat Organic Rankine Cycle (RORC) coupled with a single stage water-lithium bromide vapor Absorption Refrigerator (AR). The working fluid is chosen for the RORC is Benzene. The first and second law based performance of the proposed system has been evaluated. The novelty of this work lies in its construction where a reheat ORC has been incorporated, which does not ensure a higher efficiency rather a higher work output and a higher life span of the turbines, with respect to a basic ORC. An AR has been integrated to generate cooling effect by using the heat rejected by the RORC. A parametric variation has been performed to determine the performance of the system over a wide range of operating conditions. Results show that considering the exhaust gas from a 184.8 kW diesel engine the maximum electrical power output of 7.031 kW is obtained at the heat recovery vapor generator (HRVG) pressure of 3800 kPa and reheat pressure ratio of 0.177. The maximum COP of 0.8579 is attained at the evaporator temperature of 18°C with a cooling effect of 29.51 kW. The proposed cogeneration system poses the highest thermal efficiency of 88.29 % and exergy efficiency of 43 %.