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Post by Andrew on Sept 5, 2013 5:36:07 GMT
Ground source heat pumps that extract heat from water use antifreeze to prevent freezing even though this means that the pump is now forced to run more inefficiently once the temperature falls below the usual freezing point and the mixture remains unfrozen.
For a heat pump, a warmer source of ground water enables the pump to run more efficiently so ice cold water would provide far more heating efficiency than unfrozen water at -4C.
It seemed to me that one way to solve this problem was to have a huge tank of water in your ground loop. The other way is to have a deeper or longer ground loop but that means your circulating pump has to work harder and you lose efficiency.
A huge tank seemed possible because generally the coldest temperatures resulting in the loop freezing are only periodic, and when the pump was not working for such longer periods, there would be a bit of recovery in the naturally available ground water heat source, resulting in warmer water in the loop arriving at the evaporators heat exchanger which would prevent freezing.
So to sum up:
1. The most efficient heat pump situation for your house would not have icey water at 0C and instead would have water that was warmer than icey water
2. Icey water would provide an enormous buffer against lower efficiency if the heat exchanger icing problem could be solved
3. The least efficient method would involve antifreeze and temperatures below the temperature of ice cold water
So efficiency order is water > icey water > very cold water with antifreeze.
However, if a tank was used to keep ice cold water circulating when the pump was working for long periods, it would have to be switched out while it contained icey water or warmer water if the loop return temperature was greater than the tank temperature.
The tank therefore is of limited use since it only provides a one time source of heat to prevent freezing.
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Post by numerouno on Sept 7, 2013 8:45:48 GMT
Water in the loop would get frozen only in winter returning to the loop when it has given up its thermal energy to heating. When it returns from the loop, it is usually above 0C. It's always the difference between the in and out temps of the loop that is being utilized. The use of antifreeze is a purely technical point that has no significance to the operation of the system.
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Post by Andrew on Sept 7, 2013 9:58:56 GMT
Water in the loop would get frozen only in winter returning to the loop when it has given up its thermal energy to heating. When it returns from the loop, it is usually above 0C. It's always the difference between the in and out temps of the loop that is being utilized. The use of antifreeze is a purely technical point that has no significance to the operation of the system. Other things being equal, if water is freezing in the system, the running costs of the system are higher than if freezing is prevented by the use of warmer return water. The same reasoning applies to water that contains antifreeze that would have frozen without the antifreeze
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Post by numerouno on Sept 7, 2013 19:53:42 GMT
The use of antifreeze is standard practice in ground sourced heat pumps. There are no extra costs involved in using it.
The water is warmer entering the house than leaving the house because it has gained thermal energy underground.
This may be reversed for cooling purposes.
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Post by Andrew on Sept 8, 2013 5:22:40 GMT
The use of antifreeze is standard practice in ground sourced heat pumps. There are no extra costs involved in using it. The water is warmer entering the house than leaving the house because it has gained thermal energy underground. This may be reversed for cooling purposes. COP for a heat pump is higher in proportion to the increasing temperature of the water entering the evaporators heat exchanger
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Post by numerouno on Sept 8, 2013 12:24:42 GMT
I can't see what your point is above, as ground sourced heat pumps already have the antifreeze installed from day 1, and work perfectly well the way they are supplied.
There is no problem left for you to "solve".
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Post by Andrew on Sept 8, 2013 13:13:56 GMT
I can't see what your point is above, as ground sourced heat pumps already have the antifreeze installed from day 1, and work perfectly well the way they are supplied. There is no problem left for you to "solve". Ground source heat pumps do not have antifreeze in them when supplied. The antifreeze is in the ground loop which is supplied usually by the drilling company. As can be seen from the heat pump forums, heat pumps often do not work perfectly well as supplied. A common problem is constant operation of the pump in higher than designed for external temperatures, caused by an excessively cold ground loop due to the ground loop being unable to be sufficiently warmed by the source of heat. However, with those points dealt with, you are probably right that I did not have much of a point to make in the first place. However, there is still the basic observation that many cold climate ground source heat pumps cannot successfully operate without antifreeze in the ground loop.
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Post by numerouno on Sept 8, 2013 14:08:08 GMT
Ground source heat pumps do not have antifreeze in them when supplied. The antifreeze is in the ground loop which is supplied usually by the drilling company.
Usually it is a single company that does everything turn-key, it will drill the well, install the pump, install the tubes into the well, fill them up with the liquid, seal it up, and send the bill. There is no need for the customer to worry about the liquid at any point later on.
If the well is drilled deep enough in relation to the heating power required, there is no need to worry about it later.
This is where then expects are worth their price, and I don't think there is much of an actual failure rate at least in Finland. Presumably you would have followed something other than local blogs, as we know you don't do much Finnish. It is not "often" that the projects would not be entirely succesful, that is something you will have invented yourself.
In any case, there is nothing to prevent you from making the previous well deeper, or drilling another additional one, if the heat supply is inadequate for some reason.
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Post by Andrew on Sept 8, 2013 14:46:25 GMT
Ground source heat pumps do not have antifreeze in them when supplied. The antifreeze is in the ground loop which is supplied usually by the drilling company.Usually it is a single company that does everything turn-key, it will drill the well, install the pump, install the tubes into the well, fill them up with the liquid, seal it up, and send the bill. There is no need for the customer to worry about the liquid at any point later on. If the well is drilled deep enough in relation to the heating power required, there is no need to worry about it later. This is where then expects are worth their price, and I don't think there is much of an actual failure rate at least in Finland. Presumably you would have followed something other than local blogs, as we know you don't do much Finnish. It is not "often" that the projects would not be entirely succesful, that is something you will have invented yourself. In any case, there is nothing to prevent you from making the previous well deeper, or drilling another additional one, if the heat supply is inadequate for some reason. Obviously you do not know as much about heat pumps in Finland as you like to present to this forum. In Finland I dont think it can be said it is usual for turn key providers to drill their own wells Tom allen was a canadian driller and he now drills heat pumps wells and installs Thermia Danfoss pumps and there are some other companies who do their own drilling but as often as not the turn key service provider has a friendly driller on hand when required. The Finnish and Swedish forums have plenty of stories of failures so there is no need for me to invent the stories. Finland is an imperfect place. One set of neighbours just spent thousands on a new fence and i see it is falling down already. The fence installed alongside another of our neighbours is a total mess on our side to the point it makes our house less valueable and it was installed 'professionally'. And as i said our approved District heating installer managed to connect the pipes incorrectly for the helsinki supply water and put the outdoor sensor on the wrong side of the house. They also managed to leave us without any fresh water supply and never told us so when they left the site half way thru what was supposed to take one days work. The least they could have done was notified us. I was also surprised to find the District heating unit does not come with a cover and is not fully insulated, neither are the helsinki side of the heating fully insulated where we are paying for all heat losses. Even with the window open when i got back from NZ the boiler room was unnecessarily hot prior to me insulating many of the pipes. I would say that kind of presentation is amateurish. The company that back filled the trench also managed to bend the pipes inside the house and the first installation of the pipes were so bent that i had to ask the guy to reposition them to be level. To be fair to him he said he was overworked as normally there would be two guys doing the job - he was pretty decent about fixing it once I explained he had put the pipe clamp in the wrong holes on the wall support Given the overall high standard of things in Finland i was expecting something better. What with Nokia beginning to crumble it is all a bit of a worry. And if you think i cannot use Google translate or get my wifes assistance for difficult words to read heat pump forums you better start believing i can do just that. Älä höpsöttele!
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Post by numerouno on Sept 8, 2013 18:54:10 GMT
Turn key providers will contract everything needed for the customer, and this is the normal way to buy a ground sourced heat pump system. Ask your reference person Tom Allen.
I don't think your linguistic abilities in Finnish or Swedish allow you to provide much links to the "often failing ground sourced heat pump projects", and therefore we don't see any links from you above. If you seriously think Google translate will be of any real help, I'd be even more worried.
Perhaps ask Tom Allen on how many of his projects are "failures" and does he think everyone else in the business might fail "often" and why that might be. If a supplier would be sub par, world would get around fast these days.
Your bent new pipes or your neighbour's new fence is unrelated to this matter, as strange this might perhaps sound to you.
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Post by Andrew on Sept 8, 2013 18:56:22 GMT
Turn key providers will contract everything needed for the customer, and this is the normal way to buy a ground sourced heat pump system. Ask your reference person Tom Allen. I don't think your linguistic abilities in Finnish or Swedish allow you to provide much links to the "often failing ground sourced heat pump projects", and therefore we don't see any links from you above. If you seriously think Google translate will be of any real help, I'd be even more worried. Perhaps ask Tom Allen on how many of his projects are "failures" and does he think everyone else in the business might fail "often" and why that might be. If a supplier would be sub par, world would get around fast these days. Your bent new pipes or your neighbour's new fence is unrelated to this matter, as strange this might perhaps sound to you. So now the turn key providers use contractors You and icefisher have much in common
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Post by magellan on Sept 8, 2013 20:02:50 GMT
Turn key providers will contract everything needed for the customer, and this is the normal way to buy a ground sourced heat pump system. Ask your reference person Tom Allen. I don't think your linguistic abilities in Finnish or Swedish allow you to provide much links to the "often failing ground sourced heat pump projects", and therefore we don't see any links from you above. If you seriously think Google translate will be of any real help, I'd be even more worried. Perhaps ask Tom Allen on how many of his projects are "failures" and does he think everyone else in the business might fail "often" and why that might be. If a supplier would be sub par, world would get around fast these days. Your bent new pipes or your neighbour's new fence is unrelated to this matter, as strange this might perhaps sound to you. So now the turn key providers use contractors You and icefisher have much in common Most businesses operate that way. Why hire a full time electrician when they are only needed when it's time to hook up the power? So they contract it out. I have a geothermal heating/cooling system so have just kind of been lurking.
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Post by numerouno on Sept 9, 2013 2:29:26 GMT
Yep, it's now over half of all new residential houses in Finland that will have a geothermal heating system installed. In Sweden the figure is even higher. Retrofits are also common, and the Finnish state even paid a small incentive money for people transitioning from oil for a while.
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Post by Andrew on Sept 9, 2013 4:14:37 GMT
Turn key providers will contract everything needed for the customer, and this is the normal way to buy a ground sourced heat pump system. Ask your reference person Tom Allen. I don't think your linguistic abilities in Finnish or Swedish allow you to provide much links to the "often failing ground sourced heat pump projects", and therefore we don't see any links from you above. If you seriously think Google translate will be of any real help, I'd be even more worried. Perhaps ask Tom Allen on how many of his projects are "failures" and does he think everyone else in the business might fail "often" and why that might be. If a supplier would be sub par, world would get around fast these days. Your bent new pipes or your neighbour's new fence is unrelated to this matter, as strange this might perhaps sound to you. Your hostile suspicious attitude towards me is only describing yourself. I have got absolutely nothing to hide.
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Post by numerouno on Sept 9, 2013 9:29:32 GMT
Dude, I'm only asking where is your definitive info coming from that the installations "do not work often"? You have no link no reference to show. And that idea would be silly, of course.
I thought you said previously you don't personally know anyone who has installed one in their house, and that was a reason for your selecting municipal heating. That sounded to me like a particularly weird reason for discarding the heat pump as a solution, but I said nothing them. Perhaps you are being having second thoughts?
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