SYSTEM OPERATION

While heat pumps and air conditioners require the use of some different components in your heating and cooling system, they operate on the same basic principles.
Heat pumps and central air conditioners are "split systems," which means that there is an outdoor unit (condenser) and an indoor unit (coil). The job of the heat pump or air conditioner is to transport heat from one "station" to the other. The "vehicle" your system uses to carry the heat is called refrigerant.

In air conditioning operation, the compressor in your outdoor unit will change the gaseous refrigerant into a high temperature, high pressure gas. As that gas flows through the outdoor coil it will lose heat and condense into a high temperature, high pressure liquid. The liquid refrigerant travels through copper tubing into the evaporator coil located in your fan coil unit or attached to your furnace. The liquid refrigerant is then allowed to expand.

This sudden expansion turns the refrigerant into a low temperature, low pressure gas. The gas then absorbs heat from the air circulating in the duct work, leaving it full of cooler air to be distributed throughout your house. Meanwhile, the low temperature, low pressure refrigerant gas returns to the compressor to begin the cycle all over again.

While it’s keeping you cool, your air conditioner or heat pump also works as an effective dehumidifier. As warm air passes over the indoor evaporator coil, it can no longer hold as much moisture as it carried at its higher temperatures. The extra moisture condenses on the outside of the coils and is carried away through a drain. The process is similar to what happens when moisture condenses on the outside of a glass of ice water on a hot, humid day.

A heat pump basically reverses that process in cold weather. It takes heat out of the outside air (or the ground, if you have a ground-source heat pump) and moves it inside, where it is transferred from the evaporator coil to the air circulating through your home.

Where does a heat pump get the heat to warm your home when it’s cold outside? Well, to a heat pump, cold is a relative term. Even though 35 F air may feel cold to humans, it actually contains a great deal of heat. The temperature at which air no longer has any heat is well below -200 F. A heat pump’s heat exchanger can squeeze heat out of cold air, then transfer that heat into your home with the help of a fan coil or a furnace, which circulates the warm air through your ducts.

Heat pumps are often installed with back-up electric resistance heat or a furnace to handle heating requirements when more heat is needed than the heat pump can efficiently extract from the air.

Give us a call at (904) 819-0234 for more information.