Spraying your heat pump with water is not a good idea in my opinion.

Regarding geothermal, as you are located in Ontario, this has become very complicated and expensive with regard to vertical drilling due to the environmental issues that must be dealt with to complete an installation.

You may have 2 possibilities, one would be to use an existing well if it were deemed suitable and the other may be a horizontal loop. A third possibility might be a pond loop if you’re on a lake.

The figure of 1.5gal/ton seems incorrect. Minimum 2.4gal/ton for an open loop and 3gal/ton for closed loop configuration would be more like it and of course water temperature plays into the efficiency equation in a big way. Supply and return sources of water should be separated by a minimum of 80 feet. Freezing would be a problem to be avoided.

If you’re in ‘Muskoka Country’, do you know what your geology is like?

The ‘Sand Point’ well concept is interesting and might work but sounds more like a half-baked idea, particularly if your geology is not conducive. Do you have any idea what so ever of the effort required to strong arm a pipe 25ft into the ground? What do you do if you hit a boulder?

I would suggest putting your time, effort and money into a project that you know can be successfully completed.

IMO

SR

Thanks for the info regarding the volume requirements, the 1.5 gpm/ton did seem rather low to me as well. I have been looking for a curve or equation based on factors such as source water temperature and even ambient external temperature and insulation efficiency but so far no luck.

As for the cooling by spraying with water, I'm not clear as to why you suggest that it is not a good idea. It is exposed to the elements after all (e.g. rain). My biggest concern would be scaling due to the content left behind after evaporation but maybe there is a way around that (e.g. descaling or reducing/removing hardness, I have considered looking into a softener system to make use of my existing sand point for household use and reduce or eliminate the need for city water but am not sure if that would remove enough)?

As for the sand point, you should not be mislead by the pictures or experience of the Muskoka's and assume that all of northern ontario is exposed rock, not to mention the fact that I am not in the Muskoka area. In fact, as I mentioned in my previous post, we have a significant water source at about 10 feet below the surface and myself and a number of my neighbors have sand points into this water (which is primarily used to water lawns and gardens), with my own at about 16 feet deep on a 2" pipe. The soil is rather sandy and boulders do not appear to be an issue though i am sure an occasional one could be hit which would result in abandoning that hole.

The bigger issue, as verified by a local installer, would likely come again from the same issue I pointed out above, namely hard water build-up, though this time it would occur in the exchanger itself, leading to reduced efficiencies and emminent failure if it cannot be controlled. This variable itself will likely make the project a no-go, again however leaving the question of how effectively a softener system would work around this and provide a controlled heating/cooling fluid, and then at what cost.

On a slightly different topic, in a closed loop vertical system, what is the typical bore size for the wells? In other words, how much separation is there between the supply and return tubes?

This post was edited by Dave_Gillingham on Wed, Feb 12, 14 at 19:11

Regarding spraying an air-source condenser with water, there are numerous threads on this site and others regarding this subject. You can do a search and draw your own conclusions.

Of course I don’t assume ‘that all of Northern Ontario is exposed rock’ when I’ve experienced differences in drilling conditions between neighbors. Why would anyone assume that an area almost the size of Texas as having a uniform geology?

It sounds like you have all the expertise you need right in your own back yard, so to speak. Regarding borehole diameter, depending on what’s being installed, will generally range in size between 3 to 6-inches for residential projects. You may choose to install some sort of ‘geo-clips’ to separate and push the pipes apart and out towards the wall of the borehole.

SR