Question

somebody proposes the following system to cool a house in the summer: compress the regular outdoor air, let it cool back to the outdoor temperature, pass it through a turbine, and discharge the cold air leaving the turbine into the house. from a thermodynamic point of view, is the proposed system sound?

Answer 1

The proposed system to cool a house by compressing outdoor air and passing it through a turbine is not a sound method from a thermodynamic point of view.

Step-by-step explanation:

From a thermodynamic point of view, the proposed system to cool a house in the summer is not sound. This is because the system described does not take into account the basic principles of refrigeration and heat transfer. In order to cool a space, the system needs to remove heat from the indoor environment and transfer it to the outdoor environment. The proposed system, compressing outdoor air, cooling it back to outdoor temperature, and passing it through a turbine, does not effectively remove heat from the indoor space.

A common method to cool a house is by using a refrigeration cycle, which involves a compressor, condenser, expansion valve, and evaporator. The compressor raises the temperature and pressure of the refrigerant gas, and it flows through the condenser coils inside the heated space, transferring heat to the room. The refrigerant then flows through the expansion valve, decreasing its pressure, and enters the evaporator coils outside the house. As the refrigerant evaporates, it absorbs heat from the indoor environment, resulting in the cooling of the space.

In conclusion, the proposed system does not follow the principles of refrigeration and heat transfer, and therefore, it is not a sound method to cool a house in the summer.

Answer 2

The proposed cooling system that compresses and expands air to cool a house is not thermodynamically sound based on the principles of thermodynamics and how refrigeration cycles work to efficiently remove heat.

Step-by-step explanation:

The proposed system for cooling a house in the summer by compressing, cooling, and expanding air is thermodynamically unsound. According to the principles of thermodynamics, the process of removing heat from an environment requires work to be done, as is the case with refrigerators and air conditioners. These systems use a refrigerant which absorbs heat at low pressure in the evaporator coils (indoors), compresses the refrigerant to high pressure, and releases the absorbed heat in the condenser coils (outdoors).

Moreover, thermodynamics teaches us that compressing air increases its temperature, and simply allowing it to cool back down to the outdoor temperature will not make it colder than the outdoor air. When expanding air through a turbine after cooling, the air might not reach a temperature that is significantly lower than the initial temperature. Besides, the work input for compression would demand energy, and without a proper cooling mechanism like a refrigerant loop, the work could be wasted.

An efficient air conditioning system is designed to move thermal energy out of the house and does this through a refrigeration cycle, which involves phase changes of a refrigerant to absorb heat indoors and reject it outdoors.