A plant takes in water at 70(°F), cools it to 32(°F), and freezes it at this temperature, producing l(lbm)(s)-1 of ice. Heat rejection is at 70(°F). The heat of fusion of water is 143.3(Btu)(lbm)-1.
(a) What is Wideal for the process?
(b) What is the power requirement of a single Carnot heat pump operating between and 70(°F)? What is the thermodynamic efficiency of this process? What is its irreversible feature?
(c) What is the power requirement if an ideal tetrafluoroethane vapor-compression refrigeration cycle is used? Ideal here implies isentropic compression, infinite cooling-water rate in the condenser, and minimum heat-transfer driving forces a evaporator and condenser of 0(°F). What is the thermodynamic efficiency of th - process? What are its irreversible features?
(d) What is the power requirement of a tetrafluorocthane vapor-compression cycle for which the compressor efficiency is 75%, the minimum temperature differences in evaporator and condenser are 8(°F), and the temperature rise of the cooling water in the condenser is 20(°F)? Make a thermodynamic analysis of this process.