When asked, “How does your heat pump work?” on your Wichita-area home, you may find yourself saying, “Great! It works great!” If you say that because you are not sure how it works, here’s the scoop on your heat pump cycles.

A Little Science, Please

Heat is thermal energy transfer. Air has a lot of thermal energy. An air-source heat pump (there are geothermal and water-source heat pumps, too) pulls thermal energy from the air and draws it into your home. In summer, it pulls heat from your home’s air and pushes it outside.

Heating Cycle

Heat pumps have a liquid refrigerant circulating line, which flows through an expansion device, changing to a liquid-vapor mix. It travels to your Wichita home’s outside coil, which serves as an evaporator coil. The refrigerant absorbs heat from the air, reaches its boiling point and becomes a low-temperature vapor.

That vapor goes into an accumulator, then to the compressor, where the cool vapor is compressed, heating up. The reversing valve routes the hot gas to the indoor coil, the condenser. The gas’s heat transfers to your home’s air, dropping the refrigerant’s temperature and turning it to liquid.

Cooling Cycle

To cool your Wichita-area home in Kansas’s summer heat, the cycle reverses:

  • Refrigerant passes through the expansion device, changing to liquid-vapor mix.
  • The indoor coil is now the evaporator, so the refrigerant travels through it, pulling heat from indoor air and boiling. The vapor goes into the accumulator and compressor.
  • Heated up, the gas goes through the reversing valve to the outdoor coil, which now acts as the condenser.
  • The outdoor coil transfers heat to the outside air, cooling the refrigerant.

Defrost Cycle

If outside air temperature drops to near freezing while your heat pump is heating, moist air will freeze on the outside coil. This drops the coil’s efficiency and the heat pump senses that. It switches the pump from heating to cooling mode to send hot gaseous refrigerant to the outside coil and shuts off the outside fan.

For more information on your Wichita-area home’s heat pump cycles, contact us at Comfort Systems.

Our goal is to help educate our customers in Wichita, Kansas about energy and home comfort issues (specific to HVAC systems).  For more information about heat pumps and other HVAC topics, download our free Home Comfort Resource guide.