Entropy Change in Heat Pump: House Heating and Exterior Effects

In summary, for a heat pump to heat a house in winter, it extracts heat from the cold outdoors and releases it into the warm interior. The change in entropy of the interior and exterior of the house will both increase due to the positive change in enthalpy. However, the change in entropy will be greater outside of the house because the temperature difference between the exterior and interior is greater. This results in a larger change in entropy for the exterior.
  • #1
3ephemeralwnd
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Homework Statement



A heat pump heats a house in winter by extracting heat from the cold outdoors and releasing it into the warm interior. for the transfer of a given amount of heat, (a) how do the entropies of the interior and exterior of the house change (increase or decrease)
b)which change is greater? Assume that the temperatures inside and outside the house do not change. explain your answers.

Homework Equations



delta S = detal H / T

The Attempt at a Solution



since change in entropy is proportional to chnange in enthalpy, if the house is being heated, there is a positive change in enthalpy, and therefore an increase in entropy

but for part b, the answer in the book says change in entropy is greater OUTside of the house. why is that? the heat lost from outside is the heat gained inside, so shouldn't this be the case for entropy as well?
 
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  • #2
3ephemeralwnd said:
but for part b, the answer in the book says change in entropy is greater OUTside of the house. why is that? the heat lost from outside is the heat gained inside, so shouldn't this be the case for entropy as well?

Not if the temperatures are different.
 

1. What is a heat pump?

A heat pump is a device that transfers heat from a low-temperature reservoir to a high-temperature reservoir, using mechanical work as the driving force.

2. How does a heat pump work?

A heat pump works by using a refrigerant to absorb heat from a low-temperature source, such as the air or ground, and then compressing and transferring that heat to a higher-temperature source, such as a building or water supply.

3. What is the entropy change in a heat pump?

The entropy change in a heat pump refers to the change in the thermodynamic property of entropy, which measures the disorder or randomness of a system, as the heat pump performs its function of transferring heat from one reservoir to another.

4. How does the entropy change affect the efficiency of a heat pump?

The entropy change has a direct impact on the efficiency of a heat pump. As the entropy of the low-temperature reservoir increases and the entropy of the high-temperature reservoir decreases, the efficiency of the heat pump decreases. This is due to the second law of thermodynamics, which states that the total entropy of a closed system will always increase over time.

5. Can the entropy change in a heat pump be reversed?

No, the entropy change in a heat pump cannot be reversed. This is because the transfer of heat from a low-temperature reservoir to a high-temperature reservoir will always result in an increase in entropy, which cannot be reversed without the input of additional energy.

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