The Defrost Cycle of Heat Pump and the Significance of Thermostat on Heat Pump Defrost Cycle – Term Paper Example

Heat Pump Defrost Cycle Total Number of Words: 787 Introduction Heat pumps can function as a reverse cycle air conditioner such that this device is capable of pumping air from cool area to a warmer area during summer season with opposite effects during winter [1]. Functioning as a reverse cycle air conditioner [2], heat pump is a commonly found in home electrical appliances such as refrigerator, air conditioner, thermal comfort, and heat engine among others.
Through the use of a valve which enables the electronic equipment to provide either air conditioning or heating effect, the heat pump normally function with the use of compression cycle system that either supply or remove heat within a space or area where temperature is controlled [2]. Considering the significance of heat pump in our daily living, the different types of heat pumps will be identified and described in details. Eventually, the defrost cycle of heat pump will be tackled in details followed by discussing the significance of thermostat on heat pump defrost cycle.
Different Types of Heat Pumps
The two types of heat pumps include the compression heat pump and the absorption heat pump. The difference between the two types of heat pumps is that a compression heat pump requires mechanical energy from electricity to function whereas the absorption heat pump can operate using either electricity or fuel [4].
There are several heat pumps available in the local market. This includes the electric heat pump, geothermal heat pump, and air-source or reverse cycle chiller pump [1, 2]. In order to produce warm and cool air, the electric heat pump is operated using electricity together with its refrigeration system whereas the geothermal heat pump is operated using the heat coming from the inner crust of the Earth [2]. Likewise, heat pumps vary on heat pump rating, heat provision
efficiency, and the market price of heat pumps.
Despite the significant differences between an electric heat pump and a geothermal heat pump, both types of heat pumps can be use in producing warm air, air cooling effects, and boiling water [2]. In line with this, it is common for heat pumps to mechanically function by moving heat from area with sources of low temperature to a place with higher temperature where heat would normally sink [2, 3].
Similar to electric heat pump, the air-source or reverse cycle chiller pump also operates using electricity. The only difference between the two types of heat pumps is that the use of the air-source pump is more efficient in terms of energy saving [1]. This is possible since air-source pump would require less electricity during winter season since exterior air is cold. Therefore, the air-source pump does not require excessive energy in trying to make the exterior air cool.
Significance of Thermostat on Heat Pump Defrost Cycle
As a significant device added on heat pump, thermostat is a temperature regulating system that enables the heat pump determines the desired temperature. In the absence of a temperature sensor such as the thermostat, the heat pump will not detect the point wherein going through a defrost cycle is necessary.
Heat Pump Defrost Cycle
Through the use of a reversing valve, the heat pump is considered as a significant part of refrigerator which enables the electronic equipment to undergo a reverse cooling air flow between the internal and external coil. As mentioned earlier, the internal coil acts as an evaporator which removes warm air from the internal air and transfer the warm air to the external coil where warm air can flow externally. This process occurs when internal cooling effect is needed.
When frost condition occurs, the heat pump will undergo a defrosting cycle. Instead of evaporation, a condensation cycle occurs when the heat pump needs to defrost the ice from a refrigerator as a way of transferring the internal cold air externally through the external coil. In this cycle, the condensation process freezes onto the coil causing a significant reduction in its capacity to transfer warm air. Therefore, the defrost thermostat functions as a defrosting device which makes heat pump undergo a defrosting cycle whenever necessary [5]. In this process, the outdoor fan which transfers external cool air internally is turned off. As part of the defrosting cycle, the electric heating element of a heat pump is turned on [5].
Conclusion
Among the two common types of heat pump includes the compression and absorption heat pumps. Although there is a slight difference on how these two types of heat pumps operate, both devices can function as air conditioning or defrosting.
The thermostat is a significant part of heat pumps which monitors the changes in air temperature. Once frost condition occurs, the heat pump is expected to undergo defrosting cycle by transferring internal cold air externally through its external coil.
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References
[1] Smith, K. (2008, June 9). Retrieved June 15, 2010, from Electric Heat Pump Overview. An Energy Saving Alternative to Central Air Conditioning: http://home-interiors.suite101.com/article.cfm/electric_heat_pump_overview.
[2] Global Spec. (2010). Retrieved June 15, 2010, from About Heat Pumps: http://www.globalspec.com/LearnMore/Manufacturing_Process_Equipment/Heating_Cooling_Equipment/Heat_Pumps.
[3] Dieckmann, J. Roth, K., & Brodrick, J. (2007). From Magnetic Refrigeration. Emergine Technologies. Retrieved June 15, 2010, from ASHRAE Journal: http://www.pdfdownload.org/pdf2html/pdf2html.php?url=http%3A%2F%2Fwww.ashrae.org%2Fdoclib%2F20070727_Emerging.pdf&images=yes.
[4] Solar Heat Pump Electrical Generation System. (2010). Retrieved June 15, 2010, from A New System for Open, Location Independent, Reliable, Clean and Renewable Energy. The Energy Tower: http://energytower.org/.
[5] Meenen, S. (2010). G&S Mechanical Services. Retrieved June 17, 2010, from Heat Pump Defrost Problems With your unit freezing or icing Are Easy To Solve.: http://toad.net/~jsmeenen/defrost.html.