ES POULTRY FARM having 500 kilograms of meat enters a chiller at 8℃ and are frozen and chilled to a final temperature of -18℃ for storage in 15 hours. The specific heat above and below freezing are 3.18 kJ/kg-℃ and 1.55 kJ/kg-℃ respectively. The latent heat is 246 kJ/kg and the freezing temperature is -5℃ . Compute the product load.

• 2.85 kW
• 2.34 kW
• 3.12 kW
• 1.25 kW

How many tons of refrigeration are required to produce 10 metric tons of ice per day at -10℃ from raw water at 22℃ if miscellaneous losses are 15% of the chilling and freezing load?

• 13 TR
• 15 TR
• 17 TR
• 19 TR

Mass of ice at -4℃ is needed to cool 115 kg of vegetables in a bunker for 24 hours. The initial temperature of vegetables is assumed to be 30℃. It is also assumed that the average temperature inside the bunker is 7℃ within 24 hours period. If the heat gained in the bunker is equal to the heat removed to cool the vegetable from 30℃ to 7℃ , what would be the required mass of ice per day. Note: Specific heat below freezing of ice = 1.935 kJ/kg-K; Specific heat of vegetables = 3.35 kJ/kg-K

• 23.82
• 28.32
• 22.82
• 28.22

Calculate the tons of refrigeration required to freeze in 4 hours a 3 mm of 10℃ water on a skating rink 61m x 30m if the ground temperature is 10℃ and the air temperature above the rink is 16℃. The heat transfer coefficient from the air to 0℃ ice is 6.8 W/𝑚²-℃ and the heat transfer coefficient from the ground to -6℃ ice is 0.3402 W/𝑚²℃.

• 100.39 TR
• 101.39 TR
• 102.39 TR
• 103.39 TR

An ammonia simple saturation cycle operates with a suction pressure of 291.6 kPa and a condenser pressure of 1204 kPa develops 15 tons of refrigeration. Determine the theoretical horsepower of the compressor. The following enthalpies have been found: condenser entrance = 1653 kJ/kg, exit = 346.6 kJ/kg; compressor entrance = 1450.2 kJ/kg, exit = 1653 kJ/kg.

• 12 HP
• 13 HP
• 15 HP
• 20 HP

A refrigeration system consumed 28,800 kw-hr per month of energy. There are 20% of energy is lost due to cooling. If COP of the system is 6, find the tons of refrigeration of the system. A newly bought SAMSUNG refrigerator has a power input of 450 watts and a COP of 2.5 is used to cool five large watermelons, 10 kg each, to 8 °C. If the watermelons are initially at 20 °C, determine how long it will take for the refrigerator to cool them. The watermelons can be treated as water whose specific heat is 4.2 kJ/kg-K.

• 2240 sec
• 2350 sec
• 1210 sec
• 1550 sec

A household refrigerator with EER 8.0 removes heat from the refrigerated space at a rate of 90kJ/min. Determine the rate of heat transfer to the kitchen air.

• 128.46 kJ/min
• 152.5 kJ/min
• 134.66 kJ/min
• 150 kW

A house that was heated by electric resistance heaters consumed 1200 kWh of electric energy in a winter month. If this house were heated instead by a heat pump that has an average performance factor, PF of 2.4, determine how much money the homeowner would be saved that month. Assume a price of 0.085 $/kWh for electricity.

• 59.50
• 44.35
• 65.60
• 72.7

A reversed Carnot cycle has a refrigerating COP of 2.5. Determine the ratio 𝑇𝐻/𝑇𝐿?

• 1.5
• 1.3
• 1.4
• 1.2

A Carnot refrigerator operates in a room in which the temperature is 25°C and consumes 2kW of power when operating. If the food compartment of the refrigerator is to be maintained at 3°C, determine the rate of heat removal from the food compartment.

• 1505.45 kJ/min
• 1455.45 kJ/min
• 1560.45 kJ/min
• 1350.44 kJ/min