23CQ. - College Physics (Urone)

Question

Explain why heat pumps do not work as well in very cold climates as they do in milder ones. Is the same true of refrigerators?

Step-by-Step Solution

Answer

The heat pump does not work well in a cold climate due to the large temperature difference between the system and the surroundings, while the refrigerators work well in this scenario. 

Describe the working of the heat pump

A heat pump is a machine that is used to heat a system by transferring heat from the environment. Work must be provided to the system in order to make it warmer. This will help the system effectively take heat from a lower temperature and heat up a space at a higher temperature. 

Describe why it is not possible for a heat pump to work as efficiently in very cold climates as they do in milder ones.

In very cold climates, the temperature of the environment will be very low. The temperature difference between the environment and the system is responsible for the work supplied to the system. So, if it is too cold, the temperature difference will be large, and the work required will also be large. The coefficient of performance of a heat pump is inversely proportional to the work done. So, as work increases, efficiency decreases. That is why heat pumps do not work well in cold climates when compared with mild climates. 

Describe how the refrigerator will function in a cold climate.

Refrigerators are used for the purpose of cooling. It transfers heat from a cold body to a hot one. So, here, if the temperature in the environment is low, there will be only a small difference between the system and the environment. So, the work required will be less. Therefore, it can work well in a cold climate.

So, heat pumps cannot work efficiently in cold climates compared to mild climates, whereas in refrigerators, it is possible.