Design a hydrocooling unit that can cool fruits and vegetables from 30 to 5 °C at a rate of 20,000 kg/h under the following conditions: The unit will be of the flooded type, which will cool the products when they are transported in the channel filled with water. Products will be dropped into the water filled chute at one end and collected at the other end. The channel can have a width of up to 3 m and a height of up to 90 cm. The water will circulate and be cooled by the evaporator section of a refrigeration system. The temperature of the refrigerant inside the coils will be 2°C, and the temperature of the water must not fall below 1.5°C and must not exceed 7°C. Assuming reasonable values for the average density, specific heat, and porosity of the product (the fraction of the volume of air in a box), recommend reasonable values for a) the velocity of the water through the channel and b) the flow rate refrigeration system cooling (QL). For the calculation of the reasonable values (Velocity and QL): a) Draw a diagram of the process. b) Justify each of the properties to be used: average density, specific heat and porosity of the product. c) Determine the possible efficiency.
Design a hydrocooling unit that can cool fruits and vegetables from 30 to 5 °C at a rate of 20,000 kg/h under the following conditions:
The unit will be of the flooded type, which will cool the products when they are transported in the channel filled with water. Products will be dropped into the water filled chute at one end and collected at the other end. The channel can have a width of up to 3 m and a height of up to 90 cm. The water will circulate and be cooled by the evaporator section of a refrigeration system. The temperature of the refrigerant inside the coils will be 2°C, and the temperature of the water must not fall below 1.5°C and must not exceed 7°C.
Assuming reasonable values for the average density, specific heat, and porosity of the product (the fraction of the volume of air in a box), recommend reasonable values for a) the velocity of the water through the channel and b) the flow rate refrigeration system cooling (QL).
For the calculation of the reasonable values (Velocity and QL):
a) Draw a diagram of the process.
b) Justify each of the properties to be used: average density, specific heat and porosity of the product.
c) Determine the possible efficiency.
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