GATE 2023 ME – Question 35
Consider a counter-flow heat exchanger with the inlet temperatures of two fluids (1 and 2) being $T_{1,in} = 300$ K and $T_{2,in} = 350$ K. The heat capacity rates of the two fluids are $C_1 = 1000$ W/K and $C_2 = 400$ W/K, and the effectiveness of the heat exchanger is 0.5. The actual heat transfer rate is _____ kW.
(Answer in integer)
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Correct answer: 10
Explanation
The smaller heat capacity rate is $C_{min} = 400$ W/K. The maximum possible heat transfer is $Q_{max} = C_{min}(T_{2,in} - T_{1,in}) = 400 \times 50 = 20000$ W. With effectiveness $\varepsilon = 0.5$, $Q = 0.5 \times 20000 = 10000$ W $= 10$ kW.