I recently installed a new well at my house in rural Wisconsin. The well is capable of producing 20+ gallons per minute, and the old well is still functional. The new well has an 8" PVC casing, a 1 hp. submersible pump, and an 80 gallon bladder style pressure tank in the basement next to the antique oil furnace. There is plenty of room in the basement. A couple of weeks ago the oil burner gave out, and we have been going with our wood backup. I have always been interested in groundwater heat pumps, and in fact, that is the reason I had the new well beefed up. I've tried to educate myself on heat pumps over the last few weeks, and my searching ended up here at Geoexchange. I've learned a lot from this site, and especially the forums. I would appreciate your opinions on my situation. I had a quick test on my water, and I have pH 8.0, iron zero, hardness 20 grains per gallon or 342 ppm. Ouch. If I go open loop I'm pretty sure I'll have maintenance issues on the heat exchanger, and I imagine it would be expensive to call a pro in every time. 1) I'm pretty handy at plumbing, and I have a spare half-horse self priming jet pump. I could envision permanently mounting the jet pump on a 55 gallon drum next to the heat pump, isolating the heat exchanger, and then running pipes and valves from the jet pump into the heat exchanger lines. I could then flush or back-flush the heat exchanger with cleaning fluid circulated through the 55 gal. drum as often as neccessary. Feasible, or no? 2) When I replaced the ice machine at my restaurant I bought one that had a stainless steel freezing unit as opposed to other brands that only had copper or cupronickel units. I bought stainless because it supposedly lends itself to cleaning off mineral deposits better. Are there any heat pumps that feature stainless steel heat exchangers, or are they all Cu or CuNi ? Do some heat pumps lend themselves to cleaning better than others? 3) Am I fighting a losing battle and should I just swallow the extras I put in on my new well and proceed with a closed loop? Thanks ....... Ken
Hi and welcome, 1. Feasible but way overkill 2. cupra only 3. not really. Call in some local talent for a estimate/ feasability consult. A local pro even if paid for a diy consult will save you hours of labor and prolly thousands in mis steps. The first hurdle is your discharge water. Does your location allow class 5 injection wells or open discharge? Eric
heat exchanger Put a water-to-water heat exchanger on it. Buy two of them. One heat exchanger running - then clean the one not running with acid. Products
Thanks for the replies. Eric, I intend to go with a local pro before doing anything, but I like to educate myself beforehand and get a range of options in mind so that I can talk to him/her intelligently. That way, when I start getting estimates I don't have to waste the pros' time trying to educate me, and I can better understand what they will be talking about. I will also be better prepared to ask questions and decide which pro I want to go with. In looking at my state's DNR website, they (and Minnesota's DNR) seem to frown on injection wells. But as long as I'm not discharging into a body of water, like a lake or stream, they don't seem to mind: Quote: Regulated Geothermal SystemsSingle Pass or “Pump and Dump” System This is a system in which water is withdrawn from a water supply well, passed through a heat pump and then discharged to the ground surface or to a surface water body. If the discharge is to a surface water body, concurrence from a regional DNR office for the location and amount of discharge is required. A standard well construction notification fee must be submitted to the DNR and a notification number obtained by the property owner before the water supply well is constructed." Unquote. It seems strange that they have a problem with my returning the groundwater back down a well a couple degrees changed from what it was, but they don't mind my depleting the groundwater and running it out to the surface where it will potentially evaporate. Huh. Anyway, what type of ground surface "dumps" seem to work out the best? I live on 14 rural acres, and the house is on a moderate rise from the rest of the land, which seems to be fairly porous. Howard, would you please describe or sketch how the water to water heat exchangers would be hooked up to my water to air heat exchanger unit? It must be a pretty good idea, since Mark was favorably impressed. Thanks again, gentlemen. Ken
Thanks Thanks for the help on the heat exchangers Howard. I'm still working on the "dump" part of the loop - Ken
As long as you don't have bacterial iron build-up tends to stay modest in a heat exchanger that has solenoids down-stream, it is the drains themselves that we see plugged. You can mitigate that with planning. "Eric, I intend to go with a local pro before doing anything, but I like to educate myself beforehand and get a range of options in mind so that I can talk to him/her intelligently. That way, when I start getting estimates I don't have to waste the pros' time trying to educate me, and I can better understand what they will be talking about. I will also be better prepared to ask questions and decide which pro I want to go with." You'd be suprised how much time in the internet age trying to re-educate folks who "educated themselves" before we arrived. Bear in mind there is always more than one path to a destination and often no "right" one. Furthermore design is always best done by the contractor with local experience. What works in MI may not work in MN. I think I would contemplate closed loop before I messed around with dual heat exchangers et al. Remember with available tax credits you only pay 70 cents on the dollar for ground loops and that aside, by the time you pay fore a sediment filter, 2 solenoids, flow gauges and raters, a bigger well tank, a drain, 2 heat exchangers etc. you may find closed loop very affordable. I would be suprised if the price difference is much more than $1,000.
True dat, but would you choose high maintanence open loop over closed if the delta P (price diff) is 1,000$?
