Question

B1. 15,000 CFM of air is flowing across a cooling coil and being cooled from 91 degrees F dry bulb and 71 degrees F wet bulb (coil entering condition) to a saturated condition of 54 degrees F (coil leaving condition).

a.       What are the sensible, latent and total rates of heat transfer from the air into the cooling fluid? Use the attached psychrometric chart. Submit the chart, showing the process (i.e. show the line the air “follows” to get from the entering to leaving condition) and the associated points, readings of the variables necessary to complete the calculations, and all calculations in order to receive full credit; use of a psychometric calculator to obtain the necessary properties of air is unacceptable.

b.      If a vapor compression refrigeration system consumed 40 kW of electrical power to cool this air flow, what would be the coefficient of performance of the refrigeration system? (Recall, COP is dimensionless).

Answer 1