Heat pumps are a great alternative to a traditional HVAC system, but how does a heat pump work? Find out in this guide from the HVAC installation and repair experts at Eyman.
A heat pump functions as an alternative to the traditional HVAC system; It’s not an air conditioner.
However, both air conditioners and heat pumps collect heat from inside your home through a compressed refrigerant. As air passes over a coil within its air handler, the collected heat is subsequently transferred outside. Heat pumps aren’t furnaces either, they’re an all-in-one temperature regulator. This means it heats your house during cold months and cools your house during warm months.
While air conditioners necessitate the use of an accompanying furnace, a heat pump requires no such thing. Heat pumps can act both as a heater or a dehumidifier, depending on the circumstances. Also, instead of installing two separate systems to heat and cool your home, heat pumps provide heating and cooling within the same system by extracting heat and moving it throughout the ductwork outside your home.
How Do Heat Pumps Work?
Heat pumps don’t generate hot or cold air. Heat is always present, even in the air that seems cold. Even the ground itself contains some element of heat, which allows heat pumps to warm homes on cold days. Simply-put, a heat pump can extract heat from the air and transfer it to another area.
When the weather outside is warm, heat pumps extract heat from indoors and push it out. Warm air is sucked into the ductwork through a motorized fan. The compressor then moves the refrigerant between the indoor evaporator and outdoor condensing units. The warm air is moved through the air handler along with the refrigerant moving from the exterior condenser coil to the interior evaporator coil. The heat absorbed by the refrigerant causes air to cool, which is finally pushed throughout the ductwork, cooling your home.
When it’s cold outside, heat pumps reverse. They behave like an air conditioner, using the outside coil as an evaporator and the indoor coil as a condenser to extract the heat from outside and transfer it inside. From there, the refrigerant travels through a closed system between the indoor and outdoor units. The heat pump produces heat and uses a furnace to blow warm air throughout the ductwork in your home.
Components of a Heat Pump
A heat pump is made up of both an indoor and outdoor unit
Outdoor Unit or Heat Pump
The outdoor unit consists primarily of a condensing coil and compressor. Within this compressor lies a reversing valve, fan, and motor. It also contains defrost controls and all of the system’s main electrical components.
The air handler must be matched appropriately to the outdoor unit. It consists of an evaporator coil, blower motor, and electric heater. The air handler is responsible for moving air efficiently throughout homes.
If the heat pump is unable to effectively heat its particular home, an emergency electrical heater will power-on to assist. The electrical heater consists of all the elements also located within an air handler; the heater pack is the electric heat elements installed in that air handler.
Refrigerant is the liquid that circulates through the heat pump system, absorbing or rejecting heat. Its primary purpose is facilitating the process of heat exchange, which enables a pump to warm your home. Refrigerant is a chemical compound that uses minimal energy to convert liquid to gas and back.
Compressor & Coils
The compressor pumps refrigerant between two exchanger coils. An indoor air handler consists of a coil and a fan. In cooling mode, the coil acts as an evaporator, evaporating refrigerant at low pressure and absorbing heat from its surroundings. In heating mode, the coil acts as a condenser. In both instances, the fan is responsible for transporting air across the coil and throughout homes.
A reversing valve is an electromagnetic four-way valve that reverses the flow of refrigerant using a magnet. When connected to electricity, the reverse valve opens and enables airflow. When disconnected, it closes and flow stops. The reversing valve is responsible for the movement of air in-and-out of your home.
Thermal Expansion Valve
A thermal expansion valve is a vital element of a heat pump; it’s what makes air conditioning (cooling) possible. The expansion valve regulates the rate of refrigerant flow as it circulates throughout the heat pump system. This regulation occurs through the use of a temperature-sensing bulb. As temperature increases, the bulb opens a valve against the spring. The regulation provided by the thermal expansion valve allows for a reduction of pressure and temperature of the refrigerant.
Heat pumps are meant for moderate climates, as opposed to those with extreme temperatures. It’s recommended that heat pumps aren’t used in regions where temperatures fall below 30 degrees. In frigid temperatures, a heat pump can struggle to extract heat, and it becomes much less efficient.
Whether you are replacing an existing HVAC system or installing one for the first time, there are a number of factors to consider.
If you aren’t sure whether you should go with a heat pump or an air conditioner and furnace, call Eyman at (402) 731-2727. We will help you find the right system for your specific needs.