A COMBINED THERMODYNAMIC MACHINE 25 Pictured below is a SCHEMATIC DIAGRAM of a THERMAL MACHINE the WORK OUTPUT from two HEAT ENGINES operates a HEAT PUMP The efficiency of HEAT ENGINE 1 1 is 35 of the corresponding CARNOT HEAT ENGINE efficiency 2 the efficiency of the second HEAT ENGINE is 50 of the corresponding CARNOT ENGINE efficiency the Coefficient of Performance of the HEAT PUMP is 60 of the corresponding CARNOT HEAT PUMP Coefficient of Performance Due to heat transfer losses Q3 k Q2 where k 0 80 due to mechanical energy losses W W1 W2 where 0 75 DATA TH 500 K TM 400 K TL 250 K Q1 1 000 J a Briefly what is the function of a HEAT ENGINE What is the function of a HEAT PUMP 2 Heat engine a cyclic device designed to transform INPUT HEAT ENERGY into NET MECHANICAL ENERGY WORK OUTPUT Heat pump a cyclic device employing ENERGY INPUT to deliver HEAT from a low temperature environment to a high temperature environment b Determine each of the following performance parameters 1 2 and ENERGY EXCHANGES TRANSFERS 11 WORK and or EXPLANATIONS required 1 2 W1 Q2 Q3 W2 Q4 W Q6 Q5 0 35 1 400 500 0 070 7 0 0 50 1 250 400 0 188 18 8 0 60 500 500 250 1 20 0 07 1000 70 J 1 0 07 1000 930 J 0 80 930 744 J 0 188 744 140 J 1 0 188 744 604 J 0 75 70 140 158 J 1 20 158 189 J 189 158 31 J c d e Determine the NET HEAT TRANSFER to from the 500 K Temperature Reservoir 2 Qnet Q6 Q1 189 1000 811 J Net HEAT TRANSFER from the 500 K reservoir Determine the NET HEAT TRANSFER to from the 250 K Temperature Reservoir 2 Qnet Q4 Q5 604 31 573 J Net HEAT TRANSFER to the 250 K reservoir TRUE or FALSE 8 1 2 3 4 5 6 7 8 W2 2 k 1 1 Q1 k Q2 W2 Q3 W 1 k 2 Q1 Q5 W Q6 W W Q6 Q5 Q6 1 k 2 1 1 Q1 Q6 1 k 2 Q1 TRUE or FALSE TRUE FALSE FALSE FALSE TRUE FALSE TRUE FALSE
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