The Heat Pump is very simple once you understand the basic concept (and I promise you will after reading this). As the name suggests a heat-pump transfers or pumps heat from one place to another, (notice the use of the word “pump”- heat is not generated but rather is moved).
As they say “a picture worth a thousand words”. So let’s see one:
In this Example:
Hold on a minute- Does that mean a regular air conditioner is considered to be a heat pump?
Well let’s see:
So in theory- yes, any regular air conditioner can be considered to be a heat pump (but don’t tell this to your repair man or you will confuse him!)
So what is different between your regular air conditioner and a heat pump?
Before we discuss the difference let’s see how the heat pump acts in Cooling Mode:
Before we start notice three things:
OK- Let’s continue and we’ll start at Point 1 on the diagram:
Well that wasn’t too bad was it? Did you understand it or you need to go over it one more time?
For a fun (and safe!) experiment, put your hand to feel the air that is blowing out of your Condenser Unit (that big ugly box sitting in your back yard or over the roof). In the summer time you will feel hot air is coming out- that is the heat from inside the house! If you don’t feel hot air coming out, that means either your Compressor is not working or you are out of refrigerant and your air conditioner needs to be recharged with more refrigerant.
Well let’s look at the next diagram:
Did you notice what just happens?
Look at the reversing valve it Rotates 90o , that changes the direction of the flow of the refrigerant (Freon). It goes in the opposite direction and this is the reverse of the cooling cycle. Instead of absorbing heat from inside the house it absorbs heat from the air outside the house and “rejects” (or transfers) that heat to the indoor air. Now the indoor coil has become Condenser and the outdoor coil has become Evaporator.
Notice that the heat isn’t generated by an oil burner or a gas furnace. It is just moved (or pumped) from the outside air to inside the house. This is why the Heat Pump is so popular in moderate climates. You don’t need to have a furnace or get oil or gas delivered when the weather cools off. Because of the reversing valve you can use the same electric system as both an air conditioner and a heater!
For a fun (and safe!) experiment, try this. Take a regular window unit that you buy at any department store. Install it facing the other direction so the control panel is facing outside. Even though it is an air conditioner you will get hot air in your house. The air conditioner is actually a heater when it is reversed- this is the function and effect of the reversing valve. It changes the direction of the refrigerant and can make an air conditioner a heater or a heat Pump