Commercial air source heat pumps function by extracting heat from the outside air and transferring it inside a building to provide heating, hot water, and even air conditioning. Despite the air outside feeling cold, especially during winter, there's still enough heat energy present that a heat pump can extract. This process involves several key components working together:
The Key Steps Explained:
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Heat Absorption (Evaporation): The process begins with the evaporator. Here, a refrigerant circulates through a cold coil. This refrigerant is much colder than the outside air. Because of this temperature difference, the refrigerant absorbs heat from the air passing over the coil. Even in very cold weather, the refrigerant can absorb enough heat to begin the process.
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Refrigerant Compression: The now-warmed refrigerant, in a gaseous state, travels to a compressor. The compressor increases the pressure and temperature of the refrigerant significantly. Compressing the refrigerant makes it much hotter.
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Heat Transfer (Condensation): The high-pressure, hot refrigerant flows to a condenser located inside the building. Here, it releases its heat to the indoor air via a heat exchanger. This warms the air, which is then circulated throughout the building through the ductwork. As the refrigerant releases heat, it condenses back into a liquid.
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Pressure Reduction (Expansion): The liquid refrigerant then passes through an expansion valve, which reduces its pressure and temperature. This prepares the refrigerant to return to the evaporator and begin the cycle again.
Air Conditioning Mode (Reverse Cycle)
Air source heat pumps can also provide cooling during warmer months. In this mode, the process is reversed. The heat pump extracts heat from inside the building and releases it outside.
- The indoor coil acts as the evaporator, absorbing heat from the indoor air.
- The outdoor coil acts as the condenser, releasing the absorbed heat into the outdoor air.
Key Components and Their Roles:
| Component | Role |
|---|---|
| Evaporator | Absorbs heat from the outside air, causing the refrigerant to evaporate. |
| Compressor | Increases the pressure and temperature of the refrigerant. |
| Condenser | Releases heat from the refrigerant to the indoor air (in heating mode) or outdoor air (in cooling mode), causing the refrigerant to condense. |
| Expansion Valve | Reduces the pressure and temperature of the refrigerant, preparing it for the evaporator. |
| Refrigerant | A fluid that circulates through the system, absorbing and releasing heat. |
Benefits of Commercial Air Source Heat Pumps:
- Energy Efficiency: Can be more energy-efficient than traditional heating systems.
- Year-Round Comfort: Provides both heating and cooling.
- Reduced Carbon Footprint: Uses electricity, which can be sourced from renewable energy.
By extracting heat from the air, even in cold conditions, commercial air source heat pumps provide a sustainable and efficient way to heat and cool buildings.
