ABSORPTION COOLING SYSTEM UTILIZING DIESEL ENGINE EXHAUST HEAT

Abstract

n ABSTRACT— The global industrial development, the increasing demand for energy, the limited availability of resources for the future generations of fossil fuels, and the prevention of environmental damage caused by their burning have led to public concern. Increasing energy consumption by buildings has led the wider global attention to its social, environmental, and economic implications. In this study, the emission gases from diesel engines have been utilized to drive a single effect absorption cooling system. In this study, water and lithium bromide mixture is used as a working fluid in absorption cooling system to benefit from waste heat from diesel engine that it may reach 190°C. This system mostly require only waste heat as the energy source to function properly. It has several advantages such as lower required electricity compared with vapor compression system, and it uses safer refrigerant. Engineering Equation Solver EES was executed to analyze the performance of this system, and to study the effects of the temperature of the generator, the absorber, the condenser and the evaporator on the performance of the system and on the cooling capacity. The cycle simulation is based on the operating temperature ranges and fixed parameters which includes: Evaporating temperature within a range of 5-20 °C, generator temperature within a range of 90-120°C, condenser temperature ranges from 25 to 38°C, absorber temperature range from 25 to 34°C, effectiveness of heat exchanger range from 0.64 to 0.8, strong solution flow rate 0.05 to 1.5 kg/s. The Coefficient of Performance COP of the system, based on these inputs, reaches about 0.76 and the cooling capacity reaches to 14 kW. It is found that when the generator temperature is increased, the COP is decreased. This is because the increase in generator temperature lowers LiBr-water concentration. Also, the temperature increase of the generator increases the cooling capacity. The increase in the absorber temperature reduces the COP as well as the cooling capacity. This is due to a decrease in the concentration of the solution. The absorption rate could be raised by increasing the solution concentration. The higher the concentration, the greater the absorption rate. The COP and cooling capacity improves when the evaporator temperature increases. The increase in effectiveness of