Air is liquefied using a modified Linde-type cycle. Atmospheric air at 80.6F is compressed up to 100 atm. It is cooled down using the nonliquefied fraction and expanded isentropically to 1 atm, separating the gas and liquid phases. The liquefied fraction is 0.28 and the flowrate of air 0.83 ft3/s, measured at 1 atm, and 60F, determine:

1. The temperature of the cold extreme of the heat exchanger assuming that the energy losses of the system are 40 BTU per kmol of fed air. The ΔT in the hot stream is 5F.

2. The energy required by the compressor, as well as that produced in the expansion.