How Heat Pumps Work

Heat Pumps are an excellent choice to heat or cool your residential home.

Heat Pumps – Heating and Cooling

In Nanaimo’s moderate climate, Heat pumps can be an excellent choice to heat or cool your residential home. Heat pumps are versatile because it can heat or cool by extracting heat energy from the surrounding environment and moving it to another location. This means extracting heat from the outdoor air in the winter and taking heat from inside in the summer. But how does that process work?

As mentioned above, heat pumps transfer heat from one place to another. Unlike furnaces which create heat. A heat pump will absorb heat energy from the outside and transfer it to the indoor air, even in cold temperatures. When in cooling mode, a heat pumps operation is reversed. It will pull heat from the inside of your home and displaces it outside. This leaves only cool air in your home for summer comfort.

When deciding which type of system is right for your home, make sure you hire a contractor certified and knowledgeable about the installation of heat pump systems. Its important not to undersize or oversize your equipment.

Heat Pump Basics

A typical air source heat pump system consists of two major components, an outdoor unit (which looks just like the outdoor unit of a split-system air conditioning system) and an indoor air handler unit. Both the indoor and outdoor unit contain various important sub-components.

OUTDOOR UNIT
The outdoor unit contains a coil and a fan. The coil operates as either a condenser (in cooling mode) or an evaporator (in heating mode). The fan blows outside air over the coil to facilitate the heat exchange.
INDOOR UNIT
Like the outdoor unit, the indoor unit, commonly referred to as the air handler unit, contains a coil and a fan. The coil acts as an evaporator (in cooling mode) or a condenser (in heating mode). The fan is responsible for moving air across the coil and throughout the ducts in the home.
REFRIGERANT
The refrigerant is the substance that absorbs and rejects heat as it circulates throughout the heat pump system.
COMPRESSOR
The compressor pressurizes the refrigerant and moves it throughout the system.
REVERSING VALVE
The part of the heat pump system that reverses the flow of refrigerant, allowing the system to operate in the opposite direction and switch between heating and cooling.
EXPANSION VALVE
The expansion valve acts as a metering device, regulating the flow of the refrigerant as it passes through the system, allowing for a reduction of pressure and temperature of the refrigerant.

How a Heat Pump Works – Cooling Mode

One of the most important things to understand about heat pump operation and the process of transferring heat is that heat energy naturally wants to move to areas with lower temperatures and less pressure. Heat pumps rely on this physical property, putting heat in contact with cooler, lower pressure environments so that the heat can naturally transfer. This is how a heat pump works.

1STEP 1:

Liquid refrigerant is pumped through an expansion device at the indoor coil, which is functioning as the evaporator. Air from inside the house is blown across the coils, where heat energy is absorbed by the refrigerant. The resulting cool air is blown throughout the home’s ducts. The process of absorbing the heat energy has caused the liquid refrigerant to heat up and evaporate into gas form.

2STEP 2:

The gaseous refrigerant now passes through a compressor, which pressurizes the gas. The process of pressurizing the gas causes it to heat up (a physical property of compressed gases). The hot, pressurized refrigerant moves through the system to the coil in the outdoor unit.

3STEP 3:

A fan in the outdoor unit moves outside air across the coils, which are serving as condenser coils in cooling mode. Because the air outside the home is cooler than the hot compressed gas refrigerant in the coil, heat is transferred from the refrigerant to the outside air. During this process, the refrigerant condenses back to a liquid state as it cools. The warm liquid refrigerant is pumped through the system to the expansion valve at the indoor units.

4STEP 4:

The expansion valve reduces the pressure of the warm liquid refrigerant, which cools it significantly. At this point, the refrigerant is in a cool, liquid state and ready to be pumped back to the evaporator coil in the indoor unit to begin the cycle again.

How a Heat Pump Works – Review

A heat pump is a versatile, efficient cooling and heating system. Thanks to a reversing valve, a heat pump can change the flow of refrigerant and either heat or cool a home. Air is blown over an evaporator coil, transferring heat energy from the air to the refrigerant. That heat energy is circulated in the refrigerant to a condenser coil, where it is released as a fan blows air across the coil. Through this process, heat is pumped from one place to another.

Today was my third time using Norms and I have to say I have had extremely great interactions with this company. Dave came out today as we are looking at switching to natural gas at our house and our potential new house. Dave was incredibly knowledgeable, straightforward, honest and not pushy. Honestly, when it comes to plumbing and heating services, you get what you pay for! Can’t thank Dave and his team for always being reliable, punctual and most of all, being honest and providing outstanding work.

T. Wilhelm