A moist air flow of 5 kg/min at 30C, = 60%, 100 kPa goes through a

A moist air flow of 5 kg/min at 30◦C, Φ = 60%, 100 kPa goes through a dehumidifier in the setup shown in Problem 11.107. The air is cooled down to 15◦Cand then blown over the condenser. The refrigeration cycle runs with R-134a with a low pressure of 200 kPa and a high pressure of 1000 kPa. Find the COP of the refrigeration cycle, the ratio m˙ R-134a/m_air, and the outgoing T₃ and Φ₃.

Data from problem 11.107

An indoor pool evaporates 1.512 kg/h of water, which is removed by a dehumidifier to maintain 21◦C, φ = 70% in the room. The dehumidifier, shown in Fig. P11.107, is a refrigeration cycle in which air flowing over the evaporator cools such that liquid water drops out, and the air continues flowing over the condenser. For an air flow rate of 0.1 kg/s, the unit requires 1.4 kW input to a motor driving a fan and the compressor, and it has a cop of β = QL/WC = 2.0. Find the state of the air as it returns to the room and the compressor work QL input.

Transcribed Image Text:

Evaporator Valve Condenser Compressor Air back to room Air in 2) 3) FIGURE P11.107