Consider the heating of a house by a furnace, which serves as a heat-source rese
ID: 2992994 • Letter: C
Question
Consider the heating of a house by a furnace, which serves as a heat-source reservoir at a high temperature TF. The house acts as a heat-sink reservoir at temperature T, and heat |Q| must be added to the house during a particular time interval to maintain this temperature. Heat |Q| can of course be transferred directly from the furnace to the house, is the usual practice. However, a third beat reservoir is readily available, namely, the surroundings at temperature Tsigma, which can serve as another heat source, thus reducing the amount of heat required from the furnace. Given that TF = 810 K, T = 295 K, Tsigma = 265 K, and |Q| = 1.000 kJ, determine the minimum amount of heat |QF| which must be extracted from the heat-source reservoir (furnace) at TF. No other sources of energy are available.Explanation / Answer
dT=810-295=515 then dQ=1000 kj But extra heat flowing from room to envirnment dut to dT=295-265=30 dQf=30/515x(1000)=58.25 kj