Combined Steam Power Plant and Vapour Compression Refrigeration System Powered by Biogas Combustion Produced from tea Waste

Abstract

The given combined system is used for producing 1 MW electrical power in steam power plant by burning biogas produced from tea waste in boiler and 15 kg/s of cold water/hot water in May(summer)/January(winter) by R-134a as refrigerant vapour compression refrigeration system by utilizing power from steam turbine.The steam power plant parameters remain same for both May and January. Steam condenser pressure is maintained at 0.1 bar, boiler at 100 bar which is superheated to 500oC by burning biogas produced from anaerobic digestion of tea waste. From steam turbine 1 MW power is extracted and remaining required power are used by compressor of refrigeration system for producing cold water/hot water. In May cold water of 12oC is obtained from ambient reference temperature of Dibrugarh town, Assam at a rate of 15kg/s by circulating water in evaporator. The condenser and evaporator temperature is maintained at 30oC and 16oC respectively. Similarly, in January hot water of 80oC is obtained from ambient reference temperature at a rate of 15kg/s by circulating water in condenser. The condenser and evaporator temperature is maintained at 90oC and 16oC respectively. In May it is observed that with increase in ambient reference temperature leads to increase in the refrigeration load, which consequently increases the compressor work requirement. As the compressor work increases, the volume of biogas required and the mass flow rate of tea waste in boiler also increase slightly. In January with decrease in ambient reference temperature leads to increase in the condenser load, which consequently increases the compressor work requirement and the volume of biogas required and the mass flow rate of tea waste in boiler also increases. In January compressor work, volume of biogas and mass flow rate of tea waste in boiler is much more than May due to greater difference in temperature of hot water and ambient reference temperature.