A Study of Reducing Waste Heat Rejected By Condenser Using Thermoelectric Heat Pumps to Decrease Net Plant Heat Rate of Coal Fired Power Plant

Abstract

Paiton 1-2 subcritical coal-fired power plant applied coal switching program in order to can compete at Jawa-Bali electrical system. The calorific value of coal consumed is switched from 5200 kcal/kg to 4500 kcal/kg. As the result, it increases the net plant heat rate (NPHR) as well as the coal flow and produce more CO2 emissions. Increasing final feed water temperature can reduce NPHR because less heat needed to produce steam. One of promising method to increase feed water temperature is reusing wasted energy being rejected to environment through condenser. There is opportunity to reuse this waste heat by use of thermoelectric heat pumps (THPs). THPs convert electrical energy into thermal energy using Peltier effect. It can capture the heat released by condensation process and reused for increasing the feed water temperature, which can increase the cycle efficiency. Furthermore, it will reduce coal flow, decrease NPHR and aid the reduction of CO2 emissions. To maximize the energy recovery, a number of heat pumps can be used in series. This paper focused on finding the optimum number of heat pumps array. The expected feed water temperature rise gained from THPs arrangement is 19.81°C and potentially will contribute to 0.66% reduction on NPHR.