Chapter 9, Problem 9.62P

A two stage cascade refrigeration system uses R-12 in the high pressure loop with a condenser temperature of 300C and -100C in the cascade condenser, and R-22 in the low pressure loop with a temperature in the cascade condenser of 00C and an evaporator temperature of -30 0C. Given that, h6 = 366 kJ/kg;    h2= 421 kJ/kg. Determine the amount of ice (kg)for a 10 hrs operation if the initial temp of water is 31 0C to ice at --80C. ANSWER: 7358.9169 kg A two stage cascade refrigeration system uses R-11 as the working substance. The evaporator is at -30 0C and the high pressure condenser is at 300C. The cascade condenser is a direct contact type. The refrigeration load is 24 tons. Given that, h2 = 393 kJ/kg; h6 = 408 kJ/kg. Determine the ff:            a.) amount ofwater for a 10 hrs operation if the initial temp of water is 34 0C to 20C.                ANSWER: 22656.8019kg           b.) amount of cooling water needed for a temp rise of 130C.             ANSWER: 1.9446          c.) heat…

Fill in the blanks: A refrigeration system operates on an ideal vapor compression using R-134a with an evaporator temperature of -30°C and a condenser exit temperature of 46°C and requires a 74.6 kW motor to drive the compressor. What is the capacity of the refrigerator in TOR? Use the properties of R-134a from refrigerants' table. ToR

Consider an ideal refrigeration cycle that has a condenser temperature at 45oC and an evaporator temperature of -15oC. Show the process in a T-S diagram. Determine the coefficient of performance of this refrigerator for refrigerant 134a as the working fluid. Repeat the calculation for ammonia.