Vinefera grapes are picked when the outside temperature is 35C and then cooled to 5C within a 12-h period. For each metric tonne of grapes harvested,
a. What is the rate of heat removal from the grapes, expressed in Watts?
b. Once the grapes are cooled to 5C, and neglecting any conduction heat gain from the surroundings, would there be a need for refrigeration to hold the grapes at this temperature? If so, state the reason and estimate the expected heat removal rate required of the refrigeration system to maintain the metric tonne of grapes at 5oC. Again, please express in Watts.
c. If the thermostat on the refrigeration system malfunctions and the cooler temperature decreases to -1oC for 24 h, would you expect the grapes to freeze? Please justify your answer.