What is a heat pump? What is a heat pump water heater?
What is a hybrid water heater?
Why Blower Door Tests Are Key to Energy-Efficient Homes
When it comes to creating an energy-efficient home, homeowners often think about insulation, double-pane windows, or ENERGY STAR appliances. But one crucial, often overlooked component
If you have an air conditioner or a refrigerator, you have a heat pump. Heat pumps use special chemicals to move heat from one place to another. The chemicals draw heat into them, just like when you sweat. When you sweat, the heat of your body is drawn into the fluids on your skin. This cooling effect is heat moving from your body into your sweat. As the sweat evaporates, the heat is released into the air, if the dew point is in the right range for evaporation to happen. So, even you are a heat pump!!
Evaporation is known as a “phase change” where the liquid changes from a liquid to a vapor. As a liquid turns to vapor, it absorbs heat. The body-cooling effect of evaporation shows this. Taking all that vapor and pushing it back into a liquid phase concentrates the stored heat until it can be released again in the vapor phase.
Certain chemical vapors absorb heat very well, much more so than water. Using a compressor, if we allow these chemicals to circulate in a closed loop while in the vapor state, we can pump them down into a liquid. This liquid has stored heat that can then be released into a different place by pumping it around the loop and passing air over it with a fan. Your refrigerator moves heat out of the fridge compartment or freezer and into the house. Your air conditioner moves heat from the house and blows it outside. Heat pumps used to heat and cool a house have a reverse switch that allows them to heat in the winter and cool in the summer.
These chemicals (1,1,1,2-Tetrafluoroethane is known as R-134a, carbon dioxide is known as R-744, and both are allowed refrigerants) have global warming potential if allowed to escape into the atmosphere. These and other manufactured chemicals almost destroyed the ozone layer which protects all living things from excessive UV radiation. We learned, and acted, to prevent the “Ozone Hole” from ruining life on Earth. Banning the really reactive chemicals such as chlorofluorocarbons (CFCs) and controlling the release of less reactive ones has been a triumph of international policy, reversing the depletion of the ozone layer.
Review:
1) Heat pumps move heat from one place to another
2) Heat is moved by allowing chemicals to evaporate and condense in a closed loop system
3) When you sweat, you are pumping heat!
4) Releasing some heat pump chemicals is really bad for the environment
5) Heat pumps are also used in highly efficient home heating and cooling systems
What is a heat pump water heater?
Water heaters use combustion, electric resistance or heat pumps to heat the water in the tank. A heat pump water heater has a coil wrapped around it at the base which contains a refrigerant that will move heat from the room into the coil very efficiently. This heat passes through the conductive wall of the hot water tank into the water. In a strictly heat pump water heater, there is no backup resistance heating for high usage periods. This is good because the power requirement for heat pump domestic hot water is only 120VAC, so you can just plug them in to a dedicated circuit like a refrigerator. The hot water will be made with 60% less electricity than a regular electric water heater, so if it costs $600 per year this cost will go down to about $200 per year.
1) Heat pump water heaters can be plugged into a typical 110 wall circuit, like a fridge
2) Only the heat pump heats the water
3) Heat in the air around the heat pump is pulled into the tank, heating the water
4) Heat pump water heaters are very efficient