Cold water flowing at 0.1 kg/s is heated from 20 C to 70 C in a counter flow type heat exchange by a hot water stream flowing at 0.1 kg/s and entering at 90 C. The specific heat of water is 4200 J/(kgK) and density is 1000 kg/m3 . If the overall heat transfer coefficient U for the heat exchange is 2000 W/(m2 K), the required heat exchange area (in m2 ) is

Cold water flowing at 0.1 kg/s is heated from 20 C to 70 C in a counte

1.	Cold water flowing at 0.1 kg/s is heated from 20 C to 70 C in a counter flow type heat exchange by a hot water stream flowing at 0.1 kg/s and entering at 90 C. The specific heat of water is 4200 J/(kgK) and density is 1000 kg/m3 . If the overall heat transfer coefficient U for the heat exchange is 2000 W/(m2 K), the required heat exchange area (in m2 ) is
A.	0.052
B.	0.525
C.	0.151
D.	0.202
Answer» C. 0.151

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