Nocturnal Cooling: Principles of Natural Refrigeration

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What is the primary mechanism by which evaporative cooling reduces the temperature of a system?

Conduction of heat from the surroundings
Convection of air around the system
Evaporation of water (correct)
Radiation of heat into the stratosphere

In the context of evaporative cooling, what is the purpose of storing water in earthen pots?

To reduce heat gain from the surroundings through conduction (correct)
To increase the surface area of the water
To radiate heat into the stratosphere
To decrease the temperature of the surrounding air

Where has evaporative cooling been used for centuries to obtain cold water?

Europe
India (correct)
Africa
China

What is the primary advantage of using evaporative cooling over nocturnal cooling?

It is more practical (D) Signup and view all the answers

What is the essential condition required for nocturnal cooling to occur?

Still air (C) Signup and view all the answers

What is the approximate temperature of the stratosphere, which is relevant to nocturnal cooling?

-55°C (C) Signup and view all the answers

What is the primary mechanism by which sweating helps to cool the body?

Evaporation of sweat from the skin, which absorbs heat (A) Signup and view all the answers

What is the primary purpose of the salt in natural refrigeration methods?

To absorb heat from the solution, cooling it (C) Signup and view all the answers

What is the term for the process by which a liquid evaporates from a surface, cooling the surface?

Evaporative cooling (C) Signup and view all the answers

What is the limitation of natural refrigeration methods using salt solutions?

The dissolved salt must be recovered from the solution by heating (C) Signup and view all the answers

What is the result of the heat absorption from the water in the earthen vessel?

The water becomes cooler (A) Signup and view all the answers

What is the role of the sweat droplets on the skin in regulating temperature?

They help to regulate temperature through evaporative cooling (D) Signup and view all the answers

What is the primary function of the evaporator in a refrigeration system?

To vaporize the refrigerant liquid into a low-pressure vapor (C) Signup and view all the answers

What is the role of the fan in an air-cooled evaporator?

To circulate air from the cooled space across the evaporator coils (D) Signup and view all the answers

What type of evaporator is classified as 'dry'?

Air-cooled evaporator (D) Signup and view all the answers

What is the cause of most evaporator problems?

Dirt on the coils or restricted airflow (D) Signup and view all the answers

What is the purpose of the constant flow of refrigerant through the evaporator?

To keep the evaporator cool (C) Signup and view all the answers

What is the characteristic of the refrigerant at the end of the evaporator in an air-cooled evaporator?

It is a low-pressure vapor (D) Signup and view all the answers