When even so-called experts don't know the difference, you must admit we have a problem here.
Up north of Toronto in Markham, Ontario, Mattamy Homes is building a new subdivision that is going for net-zero emissions. About three hundred homes will have heat pumps connected by pipes to a network of wells managed by Enwave, a company that does district heating and cooling. The company calls the system "geothermal".
"This is one of those things that I wish would really work," he said. "But I think we need to be kind of chastened by history." Adams says in places where there is more geothermal activity, such as Iceland or parts of California, it completely makes sense. However, experiments with the technology in Canada have been less successful.
At this point I wanted to run out of the room screaming, because if a so-called expert and the CBC do not know the difference between real geothermal in Iceland and Ground Source Heat Pumps in Markham, then clearly I have been right all these years when I have said don't call heat pumps geothermal!
I should point out first that Energy Probe is made up of a bunch of climate deniers funded by the oil industry and shouldn't be considered a reputable source, but let's skip that for now and go back to basics.
Ground source heat pumps and geothermal are two entirely different things.
- Geothermal systems use heat directly from natural sources like hot springs, geysers and volcanic hot spots like the installation on the right in the Iceland photo above.
- Ground source heat pumps are essentially air conditioners that use soil or groundwater to cool the condenser instead of an outside coil and fan. It uses electricity to move heat energy from one place to another. Run it backward and it provides heat, and more efficiently than using electricity directly.
Fine, there is a grain of truth here. When a GSHP is in heating mode, it is indeed moving heat from the ground to the home and that heat can be assumed to be from the sun. However, in cooling mode, the GSHP is pumping heat into the already warm ground and there is zero gain of any kind from solar energy. It is not renewable, and it is running on electricity, which could well be made with fossil fuels.
I have given up complaining about this (not really, see related links below); it's one of those things that they keep saying long enough that even they believe it and publish it in ASHRAE news, where they say the Unity Temple is powered by geothermal energy. It's not; it is powered by electricity.
The Canadian industry tried to fix this and promote the term GeoExchange, which is sexier than GSHP and actually is technically correct, but it never caught on, not even with people like Mattamy Homes and Enwave that should know better.
I know I will never change anyone's mind about the use of the word geothermal for GSHPs; it is universal now. But the CBC and Tom Adams prove once again that it is still wrong.
Mattamy explained how the system works with these weird drawings of underground pipes that actually just show how complex things are below the pavement. Many in the green building world have given up on GSHPs and are going instead for a combo of highly efficient building envelopes and air source heat pumps that cost a fraction as much, and which would eliminate half of this mess of pipes, but that's another post.