Heat Pumps Explained

The heat pump is an efficient method of heating that moves heat from a cold area to a warmer area. When you first hear that it doesn’t make a whole lot of sense. You’re probably asking yourself how you can get heat from a cold area? Let’s take a look at how the heat pump works.

How does a Heat Pump Work?

So how can you get heat from a cold area? Well, every substance that is above absolute zero has heat energy in it, that can be gathered and transferred to another area, leaving that substance just a little bit colder. That still might not make a lot of sense so let’s take a look at an example that might help you to understand how this works.

In your refrigerator, there are components much like in your AC system. You have the two coils and the compressor. Inside the fridge is the evaporator coil that chilled refrigerant flows through, picking up heat from the fridge and leaving behind colder air. It then takes this heat and moves it to the coils on the back where it gives off its heat. Conversely, if you’ve ever stood over an HVAC condenser coil during the summer while the AC was running, and felt the hot air that the fan was blowing away from the coils, the heat pump moves heat to a warm area in much the same way.

Types of Heat Pumps

There are two main types of heat pumps — air sourced heat pumps (AHSP) and ground sourced heat pumps (GSHP). The air sourced heat pump is what was described above, and the one most people are familiar with. Also, if you have a modern split system AC unit, there is more than likely a reversing valve on it which turns the operation of the AC unit from that of a cooling one, to that of a heat pump.

Ground sourced heat pumps are very much like the ASHP only instead of using air to extract heat from, it will use the ground. Underneath the ground lines will be laid that an antifreeze-like solution will be circulated through in order to gather heat. It takes that heat and transfers it to the refrigerant via a heat exchanger. The benefits of GSHPs is that since the ground remains at a more stable temperature over time, the system can operate more efficiently.

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