Explore BrainMass

Physics: Problems Based on Refrigeration

Hi, I need some assistance solving the following problems:

1. An ice chest is maintained at 0 degrees Celsius by ice placed in it. The chest is cubical with each inside wall having an area of 1200cm^2 and a thickness of 4cm. Each wall is made of foam plastic with k= 1.3X10^-4 cal/cm/s/C. How much ice will melt in the chest in an hour when the outside temperature is 24 degrees Celsius?

2. How many tons of refrigeration would be needed to change .1m^3 of water to ice (all at 0 degrees Celsius) in a time of 1 hour?

3. A certain heat pump uses 1000W and delivers heat at a rate of 600 cal/s. a) How many calories of heat does the pump extract each second from the outside? b) What is its coefficient of performance?

Solution Preview

Please view the attachment.

1. Heat transfer will take place as conduction when there exists a temperature gradient in a solid or fluid. Conduction can take place when a temperature gradient exists in a solid (or stationary fluid) medium.

Energy is transferred from the more energetic to the less energetic molecules when neighboring molecules collide. Conductive heat flow occurs in the direction of decreasing temperature because higher temperatures are associated with higher molecular energy.

The equation used to express heat transfer by conduction is known as Fourier's Law and is expressed as:

q = k A dT / s (1)


q = heat transferred per unit time (W, Btu/hr)

A = heat transfer area (m?, ft2)


Solution Summary

This solution is comprised of a detailed response which illustrates how to solve each refrigeration problem posed in this inquiry. All equations and variables required are provided in the solution. To view the solution, a Word document needs to be opened. Additional website resources are also listed.