Introduction
Air source heat pumps use a cycle of condensation and evaporation to transfer heat from the air to a desired location. The units are extremely efficient and produce very little emissions compared to their alternatives. [1] The system can be used in conjunction with other more traditional applications to provide a constant source of warm water and air.
How it Works
Air source heat pumps use the natural processes of evaporation and condensation to transfer thermal energy from one location to another. The most common application involves an indoor and outdoor component consisting of pipes that coil at the extreme ends of the system where the physical units themselves sit. In between the two coils is a condenser. The coils are filled with a wide array of liquid refrigerants, with varying properties based on the location of their installation and local conditions. The unit can heat and cool a target, depending on which direction the coolant flows.
Heating Mode: In heating mode, the external coils are exposed to warm outside air, that causes the refrigerant to evaporate. In the process of evaporating, some heat from the outside air is transferred to the liquid as it turns into gas. The gas passes through a compressor, the added pressure increase the amount of energy present before it passes on to the final stage. Once the gas enters the indoor coil it is allowed to expand and then condense back into a liquid, releasing the stored heat from outside. [2]
Cooling Mode: During the warmer months of the year, the cycle can be switched by changing the rotation of the flow through the system. The coils inside a building pull heat from the warm air and through the same process of evaporation and condensation used in the heating mode, releases the heat to the outside air.
The Compressor and Expansion Valve
These are the two most fundamental facets of the system, as they drive the processes behind condensation and evaporation, respectively. The Compressor receives warm gas immediately after evaporation, and compresses the gas to store more of its energy while simultaneously releasing that thermal energy through the coils before hitting the expansion valve. The expansion valve allows the liquid that was just condensed and cooled from a gas to further lose some of the energy that was built up through the compression process. The liquid now has a large amount of potential energy before reentering the loop.
These two systems, in addition to the fans driving air over the coils, require very little electricity to operate and have very minor to no carbon emissions depending on models used.
See also
- LINK TO THE OTHER VOC IN STANDARD CONSTRUCTION MATERIAL PAGES
- A FEW LINKS TO OTHER RELEVANT SITES OR INFO
References
- ↑ http://www.energysavers.gov/your_home/space_heating_cooling/index.cfm/mytopic=12620
- ↑ www1.eere.energy.gov/library/pdfs/28037.pdf