Ground source cooling — no heat pump ?
I’ve been reading a lot of the questions and comments on different variations of ground source heat pumps, I’ve been kicking around an idea for while that may be unconventional because I haven’t seen it mentioned yet.
My requirements may be unconventional as well, as I am interested in comfort, more that cooling, and a solution I am interested in needs to minimize its affect on the original fabric of our 1928 brick Colonial. Which I will explain.
Our 1928 Colonial is a wood framed home, clad in two courses of brick. It retains 99% of its original plaster walls. It retains its original wooden windows, which are fairly well sealed with vintage interlocking weather stripping, meaning there are no noticeable drafts from the windows in the winter. No meaningful insulation at this time.
We cool the house the old fashioned way, we open the windows at night and close them during the day and keep the shades drawn. Cool night breezes keep the home cool and there is a 100 year old oak that shades half of the house.
The house is almost always cooler inside. Normally the house won’t exceed 78 degrees throughout the day during the summer. The house does a fantastic job of absorbing the heat during the day and releasing it during the night.
Until the 95+ day/night heat waves hit. Without the cool nights, after a couple days the home loses its capacity to cool off. We live in NJ in a NYC Suburb.
We are not interested in the cost/intrusion of central air, window units are out because of the negative visual impact to the home, and mini-splits are out as well for the internal visual impact.
We are looking just for improved comfort while we sleep, for the most part we are out and about during the day. Lowering the home to a specific temperature is not important. We just use fans now so looking for an improvement over that, and focused in the bedroom.
My idea is to use a whole house dehumidifier to lower the humidity in the home when needed, this should improve comfort. And to use water cooled air handlers which I can install in the attic above the bedrooms to exchange and cool the air there. I expect I can run the cool water piping in the 2×4 walls and insulate them in the space. This will minimize the impact to the fabric of the home, and can be accomplished during other renovations.
The unconventional part of this is the method of chilling the water. I want to use a 500+ gallon (whatever is required) underground cistern to store and allow the ground to cool the water over time. The cost of deep drilling a heat exchanger puts that aproach out of reach, I don’t think we have enough space in our back yard to lay out loops. The idea is to have a large volume of water that can absorb the heat and return it to the ground during the day when we are not using the system. I borrowed this idea from the electric companies that installed large water tanks in customer homes, heated them during the evening for heating during the day to time shift the electricity usage.
I think this could work. The ground temperature of 57 is higher than normally used, but I think would still be effective. I think the trick is to size the cistern effectively.
And again, the important part is improving comfort, not necessarily lowering the temperature of the home to a specific number. Dehumidifying and cooling the air in the bedroom may be enough to make sleeping during the heat waves possible without waking up in a pool of sweat.
So what could I be missing ? What may trip me up if I try this out ? What haven’t I thought of and should consider ?
Thank you in advance for your thoughts.