Refrigerator Heat Pump



The refrigerant is usually put through a compressor that gradually raises the gas pressure and enhances the temperature. Then through the ''condense coils'' the hot gas flows to heat up the inside area which is of higher temperature. If the freezer or refrigerator's temperature is kept at zero degrees Fahrenheit then the food will remain at a safe temperature so that it can be stored and consumed later after 3 or more days.

Figure 1: Refrigerators and Heat Pumps

The heat is then transferred to the room and then again condenses back into ''liquified'' form. Heat pump is the ''mechanical compression'' cycle which can be reserved to cool or heat a specific space.

What is a Refrigerator?

A refrigerator is mainly used to separate gases, dehumidification of air, colling for preserving, and condensation of gases. This is determined as the physical device that helps to transmit heat from a cold space to a hot space. Refrigerators mainly use the ''mechanical working'' principles to transfer heat from one place to another (Cu et al. 2019).

The main purpose of this machine is to remove the heat from a cold reservoir. The inside space of a refrigerator that is often for household purposes or even in an ''air-conditioning'' unit works through this principle.

Figure 2: A Refrigerator

The refrigerator usually absorbs heat Qc from a ''cold reservoir'' at ''Kelvin temperature'' and then discards heat Qh at ''Kelvin temperature'' to the ''hot reservoir''. The electricity bills are generated on the basis of the energy consumed by the motor that is constantly moving inside the refrigerator as a coolant by the coils.

Components of Refrigerator

There are various methods of cooling and heating in the industry but the refrigeration cycle method is more effective than all others as the process is much faster. The mission of this ''refrigeration cycle'' is to absorb heat and reject heat from a specific space (Sayegh et al. 2018). The ''refrigeration cycle'' is sometimes also referred to as the ''heat pump cycle'' which denotes routing the heat away from the space that needs to be cooled. This method is accomplished by manipulating the working pressure of the refrigerants by incorporating water, air, and synthetic refrigerants. This method works through a cycle of expansion and compression.

Figure 3: Components of a Refrigerator

The equipment that can make the refrigerant processes easier are the compressor, evaporator, condenser, and also expansion device. The compressor is the beginning step where the ''refrigeration cycle'' starts. It is the tools that gradually enhance the working pressure of the gas. There are three main types of compressors scroll, reciprocating, and rotary compressors. Next the condenser or ''condenser coil'' helps in heat exchange in the loop of a ''basic refrigeration''. The ''expansion device'' creates a drop in the working pressure after the ''refrigerant'' leaves the condensers (Wallerand et al. 2018). The evaporator is determined as the second exchanger of heat in a refrigeration process. It deals with the function of the ''business end'' which is heat absorption.

Refrigerator working principles

The refrigerators work through a principle where the ''refrigerant circulating'' in its inner space changes the liquid into the gas. The inside space of a refrigerator that is often for household purposes or even in''air-conditioning'' unit works through specific principles. Those effective working principles are separate gases, dehumidification of air, cooling for preserving, and condensation of gases.

Figure 4: Working principles of a Refrigerator

When the liquid in a refrigerator changes into gas then a process occurs that is evaporation. During this process, the surrounding area gets cool and then desired effect is produced. In the refrigerator the process of rejecting hot temperature stars from the compressor mechanisms. There are three types of compressors that can serve the process scroll, reciprocating, and rotary compressors (superradiatorcoils, 2021). The compressor of a refrigerator increases mechanically the temperature of the fluid as a refrigerant by creating a force so that it can move via a ''low-volume pipe''. The ''refrigerant liquid'' enters into the compressors as ''low-temperature'' and ''low-pressure'' gas, and after that leaves the compressor at a high temperature and high-pressure gas state.

Applications of a Heat pump

The "mechanical compression" cycle of the heat pump can gradually be reversed to either cool or heat a controlled area. A heat pump mainly dumps heat to a particular area. Both of them work on opposite principles. The application of heat pumps can be used in space heating, where it is used to heat an area like houses, greenhouses, and workplaces.

Figure 5: Heat Pump

In water heating, heat is generally recovered from households and industries' appliances by heat pumps. In the case of process heating, in various industries, these heat pumps are utilized to heat up the ''process fluid'' before the start of the reactions (libretexts, 2022). In the heat recovery process, the heat pumps are utilized in order to recover heat from other reactions.


The cycle of refrigeration is determined as a method of cooling that can provide individuals with relief on a hot and humid day. Refrigerator works on a principle for keeping a specific area and things cool. The temperature of a refrigerator is set between 35 - 40 degrees Fahrenheit. The refrigerator works on the principle of a reverse ''heat engine''. The machine takes the heat from the reservoir that is cold and then works on it according to the amount of heat that has been transferred into the ''heat reservoir''.


Q1. What is a simple representation of Refrigerators?

In a refrigerator, there are two main bodies that are lower or cold temperature which is the freezer and the hot temperature body which is present in the surroundings. The refrigerator works on the principles of a ''reverse heat engine''.

Q2. What are the major differences between Refrigerators and heat pumps?

A refrigerator is to remove heat from a particular area and a heat pump mainly dumps heat to a particular area. Hence, they work on opposite principles. In the refrigerator the process of rejecting hot temperature stars from the compressor mechanisms.

Q3. What is the Expansive Valve and Condenser in a refrigerator?

The ''flow control'' device is also known as the expansive valve of a refrigerator. This device generally controls the liquid refrigerant's flow or the coolant into the ''evaporator''. This device is very sensitive and small in size. Coiled cubes set are present in a condenser and have external fins and are situated at the back of a refrigerator. It helps in the ''liquefication'' of ''gaseous refrigerants''.



Cui, Y., Zhu, J., Twaha, S., Chu, J., Bai, H., Huang, K., ... & Soleimani, Z. (2019). Techno-economic assessment of the horizontal geothermal heat pump systems: A comprehensive review. Energy Conversion and Management, 191, 208-236.

Sayegh, M. A., Jadwiszczak, P., Axcell, B. P., Niemierka, E., Bryś, K., & Jouhara, H. (2018). Heat pump placement, connection and operational modes in European district heating. Energy and Buildings, 166, 122-144. Retrieved from:

Wallerand, A. S., Kermani, M., Kantor, I., & Maréchal, F. (2018). Optimal heat pump integration in industrial processes. Applied Energy, 219, 68-92. Retrieved from: https://infoscience.epfl


libretexts (2022). About: Refrigerators and Heat pumps. Retrieved from: [Retrieved on June 11, 2022]

superradiatorcoils (2021). About The 4 Main Refrigeration Cycle Components. Retrieved from: [Retrieved on June 11, 2022]

Updated on 13-Oct-2022 11:19:47