Actually what I was saying is that once an installation moves beyond cookie cutter then costs skyrocket. The problem is that anything that isn't absolutely plug and play will almost certainly require a lot of extra attention and because that work is only amortized over a single system it gets very expensive.
Its not that anything is "wrong" its just the nature of doing a one off job. Ideally what happens is that new and better technology becomes mainstream and standardized so that its cookie cutter driving down the installation cost and making it competitive.
We are beginning to see that with one of my favorite products a high efficiency furnace with heat pump. Its a complete system including the controller that automatically choosing between heating with gas or using the heat pump based on the outside temperature. That seems like a very good idea and it shouldn't add but a small amount to the equipment cost and nothing to the installation.
Work a few decades in a manufacturing area and you learn you don't want a special product. You want something that is made by the millions. There is a lot of time and effort in quality control and design on large run products.
Spare parts are easy to fine. Manuals for repair exist. Etc, etc. One off designs are great if you like to tinker but never worth is if you pay someone else to do it.
Friend of mine bought a house with a wind mill on the property. I though it was pretty cool. He told me there was a huge maintenance required every 5 years that cost more than all the electricity it would produce.
Why is a SCW not viable for a home?
fsq4cw: Why is a standing column well not a viable option for a home? Is that just in your area where bedrock may be too deep or a general statement that would apply everywhere?
Originally Posted by fsq4cw
I am actually considering it and other than the water quality and availability issues it shares with open loop it seems to have most advantages of closed loop and I would think it should be less expensive since it only requires about 50 to 60 feet of drilled 6" hole per ton. I have a lake I can discharge any bleed into but my plan would be to size it so that would rarely happen.
Another attraction for a SCW is a smaller footprint and "less disruption to the yard". It seems that one SCW less than 400 feet deep should handle a 5 ton load whereas that normally requires five 200 foot vertical loops.
I'm looking a one commercial application where one SCW 1000 feet deep should be able to handle a 20 ton load as opposed to twenty 200 foot vertical loops 20 feet apart - a lot of area disrupted.
My other attraction for SCW versus closed vertical loops is that I don't trust the grout. It seems to me even a fraction of a percent "shrinkage" means there is a tiny gap between grout and earth. If it is full of water it probably has a high heat transfer coefficient but what if it dries out over time?
One of my concerns about open loop and a SCW shares this potential problem is "if the well runs dry you have no A/C" and curing that problem isn't quick. But if I do choose an SCW for my home I will install a city water line to be able to fill the well (or supplement it if the level drops). If the aquifers supplying the well were dry they would probably bleed away a good bit of water I was paying for but at least I'd have A/C until I could get a well driller out to drill deeper or install another well.
Although I've never heard of anyone doing it I have wondered if drilling the vertical loop holes planning on having them fill with water (like an SCW) and simply putting the HDPE loops in the water - not grouting them - might work and provide better heat transfer than grouting them. You probably wouldn't get much advection benefit but I'm comparing it to a grouted loop where you get none anyway.
You'd still have the hole accessible if a repair is needed to the loop. (I worry about tree roots breaking the grouted loop and rupyuring the hdpe loop.) It would be subject to the same risk of the water table dropping and the hole drying out but if that will decimate the heat transfer of a grouted hole it is a similar risk to me. I guess the hole might collapse if not in rock but once you grout a vertical loop you have lost the opportunity to go back and drill deeper or repair a damaged loop.
sbe, this is the Ask Our Pro's forum, and only Pro members that have been vetted by the AOPC may post advise here. Please apply to the AOPC today, thank you.
You can find the rules for posting and qualifications here.
Further infractions may result in loss of posting privileges.