Modifying the steam plant condenser by incorporating a vapor compression refrigeration system, which is utilized to chill the water used for cooling the condenser air cooler, is proposed in this work. Hence a considerable drop in air temperature is obtained, and more steam associated with air is condensed resulting in reducing both steam lost and vacuum pump power. A thermodynamic analysis is developed for working out the performance of the proposed hybrid system. The results obtained using this analysis showed that for a condensate subcooling of 3°C the total work saving due to this modification has maximums of 38.5, 33.9 and 28.9% and occur at temperature reduction below the condensate temperature of 12, 10, and 8°C when the temperature of steam admitted to the condenser is 20, 30, and 40°C, respectively. The savings in steam lost through the vacuum pump in these cases amount to 87.7, 84, and 79.2%, respectively. It is recommended to select the decrease in condenser air temperature in the range of 4°C higher than those decreases, at which the minimum total work comes about, as the saving in steam lost becomes fairly greater (5–7%), while the maximum increase in minimum total work is 3%.
Part of the book: Low-temperature Technologies