How Does an Air Source Heat Pump Work?

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How Does an Air Source Heat Pump Work?

An air source heat pump (ASHP) is a type of heating and cooling system that transfers heat between the outside air and your home. It operates on the principle of extracting heat from the outdoor air and transferring it indoors for heating, or extracting heat from indoor air and transferring it outside for cooling. Here's a basic explanation of how an air source heat pump works:

1. Absorption of Heat:

   
   

   • Heating Mode: In the heating mode, the heat pump absorbs heat from the outdoor air. Even in cold weather, there is still heat energy present in the air. The heat pump's refrigerant, a special fluid with a low boiling point, circulates through an outdoor coil (evaporator coil) and absorbs heat from the air.

     
     

   • Cooling Mode: In the cooling mode, the process is reversed. The heat pump absorbs heat from the indoor air, and the refrigerant carries this heat to the outdoor coil (condenser coil) where it is released into the outside air.

     
     

2. Refrigeration Cycle:

   
   
   • The refrigerant circulates between the indoor and outdoor coils, changing from a liquid to a gas and back again. As it evaporates in the outdoor coil, it absorbs heat, and as it condenses in the indoor coil, it releases heat.

3. Compressor:

   
   
   • The refrigerant is compressed by a compressor located in the outdoor unit. Compression increases the temperature of the refrigerant, making it capable of releasing heat to the indoor air during the heating mode or absorbing heat from the indoor air during the cooling mode.

4. Indoor Unit:

   
   
   • In the heating mode, the indoor unit contains a coil (evaporator coil) where the refrigerant releases its absorbed heat to warm the indoor air. In the cooling mode, the indoor coil acts as a condenser, releasing heat extracted from the indoor air to the refrigerant.

5. Distribution System:

   
   
   • The heated or cooled air is then distributed throughout the building using a fan and a system of ducts or a ductless mini-split configuration.

The efficiency of an air source heat pump is measured by its Coefficient of Performance (COP), which represents the ratio of heat output to the electrical energy input. ASHPs are known for being energy-efficient, particularly in moderate climates. They are an environmentally friendly alternative to traditional heating and cooling systems, as they use the ambient air as a heat source or sink, reducing the reliance on fossil fuels. However, their efficiency may decrease in extremely cold climates, so it's important to consider the local climate when evaluating their suitability for a particular location.