Heat Exchanger Problem
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22.16 Compressed air is used in a heat-pump system to heat water, which is subsequently used to warm a house. The house demand is 95,000 Btu/h. Air enters the exchanger at 200 °F and leaves at 120 °F, and water enters and leaves the exchanger at 90 and 125 °F, respectively. Choose from the following alternative units the one that is most compact. a) A counterflow surface with and a surface-to-volume ratio of 130 ft 2 /ft 3 . b) A crossflow configuration with the water unmixed and air mixed having and a surface-to- volume ratio of 100 ft 2 /ft 3 . A crossflow unit with both fluids unmixed with and surface-to-volume ratio of 90 ft 2 /ft 3 .
description
Heat exchanger problem.
Transcript of Heat Exchanger Problem
22.16 Compressed air is used in a heat-pump system to heat water, which is subsequently used to warm a house. The house demand is 95,000 Btu/h. Air enters the exchanger at 200 F and leaves at 120 F, and water enters and leaves the exchanger at 90 and 125 F, respectively. Choose from the following alternative units the one that is most compact.
a) A counterflow surface with and a surface-to-volume ratio of 130 ft2/ft3.
b) A crossflow configuration with the water unmixed and air mixed having and a surface-to-volume ratio of 100 ft2/ft3.
A crossflow unit with both fluids unmixed with and surface-to-volume ratio of 90 ft2/ft3.
