Hello, I am in the Buffalo, NY area, and we are looking to do a subdivision entirely heated with geothermal systems. The houses are going to be very tight and well insulated, and most of the homes will be 3 tons (based on heat loss calcs). The builder is hoping to put in an individual horizontal loop for each lot to keep costs down. I've installed a lot of geo, but always have more space than is available. The lots are approximately 45'-50' wide and 100' deep. The house sits back 15'-20' from the front lot line, and the houses about 50-55' deep, which leaves a back yard of 30' deep. Ideally, they do not want to use up the whole back yard in case a pool goes in. There is a minimum distance of 4' between the house and the side lot lines, so that's all we have on the sides. Can you folks provide some insight or design thoughts for me, or direct me to a loop engineer? My main distributor for geothermal heat pumps/supplies keeps pushing drilling, but for the sake of helping this project go ahead, I want to pursue all options. I know drilling will be a lot easier, but a horizontal loop would be much cheaper, hence much more likelihood of actually going in. Here are some of my design thoughts: 1. How far can a portion of the loop be from the foundation wall? Rule of thumb is 5', which obviously wouldn't work with our distance of 4' house to lot, but could we go much closer? What if the foundation wall is an ICF or a steel with ultra insulating capabilities? 2. What do you think of digging a very deep pit excavation (12-14' deep) and laying the pipes in 24" spacing in the pit, backfilling 2' of dirt and compacting, and installing another pipe? There is no problem with dirt, since it is an open subdivision. We could even do the loop before the house is excavated. This should get us below most pools, even with deep ends (I think?) I have attached a prelim drawing of this type of setup, using front and back yards. What are your thoughts? Any creative suggestions for a good loop design that could be replicated over multiple homes? Thanks!

I think your best bet is drilling. The problem i see with a loop field as you describe is soil saturation,thus reducing efficiency of geo.Depending upon the number of homes and distance between lots , it may be possible to build a park or lake in complex and then use this as your heat exchanger for all of the homes. The only drawback would be pump hp and would the homeowner association pick up the energy tab.

What about a shared vertical system...possibly open loop with reinjection?

Have you looked into open loop? Or perhaps someone has input regarding using the entire lot - including trenching where the house will be.

Vertical, open loop, standing column well all work horizontal looks a little unsuited for the job, unless you can tap some common area (i.e. employ neighbor hood park, easments, storm drain system and basin etc).
Shrinking loop footprint is the geo holy grail, but not when we tank efficiency.
j

Hi GeoAdam, With such minimal space available vertical-closed is almost certainly the best choice available. To overcome the higher capital cost of this option you should check out EarthPoint Energy (http://www.earthpointenergy.com). EarthPoint is a thermal energy utility co. that works with individual homes, subdivisions and commercial buildings to reduce that up-front capital requirement; to allow geothermal to be more readily adopted. Essentially, the homeowner (in this case) will receive an EarthPoint Energy utility bill every month; that monthly bill depends on the loop size (i.e. 3,4,5 Ton etc.). These monthly bills are guaranteed never to increase (built into the contract). EarthPoint will work directly with subdivision developers to establish rate schedules for the development. EarthPoint then commissions a loop installer to install the vertical system. From there the dealer/heat pump installer steps in for the mechanical work. If you would like more information send me a message and i'll get you my contact details and get more information into your hands ASAP. Best Regards.

jhunter, do you work for EarthPoint? If so, I have a few questions for you.

I tried to contact them and had my mail returned.
j

Hi Joe,

Apparently the email server was down for a period of time recently. Please try and connect with them again: [email protected]

Best Regards.