Quote:
Originally Posted by jawagord
Drake landing doesn’t use geothermal as a heat source. Solar is the heat source and the roof panel heated water mixture is pumped underground for storage to use later in the evening. Governments provided about $100,000 per house subsidy for this community system so not likely to be repeated.
Shallow GT works in Alberta but the power costs to upgrade the heat is quite high so you get a big power bill each month.
Quite often, geothermal heating systems are mistakenly confused with Geyser type installations we find in countries with underground volcano activity like Iceland. The constant ground temperatures (6-8° C) we find below the frost line are not hot enough to heat your home directly, which is why you will have a geothermal heat pump inside your house. The geothermal heat pump is able to convert this 6-8°C to 40-50°C through a refrigeration process. Sounds like magic? Think of a geothermal system like a giant refrigerator. Your fridge is able to cool by extracting heat from the air inside the fridge and ‘dumping’ that heat in the back (notice how your fridge is very warm on the backside?). Even when your freezer section is already below 0° C, the refrigerant is still able to extract heat from the air. A geothermal system works based on the same scientific principles. The ground loop pipes are run into the home’s mechanical room where a geothermal heat pump with environmentally friendly refrigerant is able to extract energy from the ground loop fluid. In this extracting process, the refrigerant in the heat pump turns from liquid state into a vapor state. This refrigerant vapor is injected into a compressor, where it is compressed. The compression of the vapor drastically increases the temperature of the vapor, making it hot enough to heat your home. Through either an Air or Water heat exchanger in the heat pump, the hot vapor refrigerant is able to release its heat to your home. By extracting energy from the ground loop fluid, the temperature of the fluid drops to values typically below 0° C, making it much cooler than the surrounding ground temperature. This colder ground loop fluid is pumped back into the much warmer ground where it will absorp heat from the ground again to make the cycle complete. The neat aspect of a geothermal heat pump is that it can also work in reverse for cooling purposes. In this process, heat is extracted from the warm air inside the house and ‘dumped’ back into the much cooler ground.
https://www.thermalcreek.com/frequen...ked-questions/
https://www.dlsc.ca/
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Actually it's something of a hybrid it looks like. It's effectively using the ground as a heat sink to store thermal energy which it extracts to transfer heat through the condenser of the heat pump, used to effectively heat buildings when there is demand. What I'd be curious about is how much you can raise the ground temperature and how long that heat will remain. The last thermal storage project I worked on was a large storage tank buried under a building at the Edmonton airport which was designed to be cooled overnight when capacity was low and drawn out during the day when demand was high. It worked
okay.. not great but okay.
The power costs you refer to are simply a factor of the size of compressor, condenser and associated specialties required for a heat pump to work in Alberta. I know they work here, our neighour has a shallow geothermal system with piping buried down underneath his slab on grade garage and a heat pump for the house. I believe he supplements heating with electric.
As I said heat pumps have their greatest potential in places like Vancouver where the climate is mild and heat from outside air can simply be transferred inside. An air-to-air heat pump. Once you get into cold climates you need to provide heat to the evaporator (Which is what the heat sink is in a shallow geothermal application) so a lot of condo buildings that use heat pumps will supplement the heat required for them to work by piping hot water from a heating boiler to the evaporators on the fan coils.
EDIT: I found some interesting information about the thermal storage system at that site. It looks like it took some time for the temperatures to get to a point where the system was effective (I actually think I remember that from the news when it first started) but over a number of years the system has reach equilibrium and is now working effectively
https://www.dlsc.ca/borehole.htm