Water to water heat pump

moan 77

Hi all,
I've touched on this before, I have an old disused water well in the house next door about 30 meters away and I've been thinking of drilling my own well on my site for two reasons 1. For possible drinking water if needed in future( the well in the house next door is contaminated from some septic tanks leaking in the area). 2. I'm thinking of using this water as a medium for a water to water heat pump. My biggest problem is how I should use this water should I pump it to a ice bank and harvest it's heat there or should I use glycol loop down into the well( I'm afraid of a leak which could lead to contamation of water supply or thirdly should I use a brine solution.
I've had a lad in and said from looking at the old well near by I should hit water about 20 to 30 meters down but he would have to drill and divine first.

Does anyone out there have any idea which way I should proceed to harvest the heat from the water or would I be better to go for an air sourced heat pump as my site is too small for ground sourced one.

Do-more

I'm no expert on these matters, but a few years ago I did speak to someone knowledgeable on the subject and they outlined a few concerns about direct well water heat pumps on a couple of grounds, from memory the two major concerns were:

One that the energy cost for constantly pumping up the water to the heat pump whilst the system is running will negatively effect your COP.

And the second regarded the temperature of the well water, the heat pump should be stripping about 7 degrees of heat from the water and that cooler water is then thrown back into the well, are you sure that the water in your well will always be above 8 degrees C year round in such circumstances? If not you run the risk of the water freezing in your heat pump which could have disastrous consequences.

Sorry I can't be more helpful but that might be a starting point for further discussion.

Condenser

moan 77 wrote: »

Hi all,
I've touched on this before, I have an old disused water well in the house next door about 30 meters away and I've been thinking of drilling my own well on my site for two reasons 1. For possible drinking water if needed in future( the well in the house next door is contaminated from some septic tanks leaking in the area). 2. I'm thinking of using this water as a medium for a water to water heat pump. My biggest problem is how I should use this water should I pump it to a ice bank and harvest it's heat there or should I use glycol loop down into the well( I'm afraid of a leak which could lead to contamation of water supply or thirdly should I use a brine solution.
I've had a lad in and said from looking at the old well near by I should hit water about 20 to 30 meters down but he would have to drill and divine first.

Does anyone out there have any idea which way I should proceed to harvest the heat from the water or would I be better to go for an air sourced heat pump as my site is too small for ground sourced one.

You'll need two wells. One supply and one dump well which should be at least 15m from the first. You may well hit water at 20m but that doesn't mean that you will get sufficient quantities of water at that level to supply the pump. The amount of water you need will depend on the HP size. The COP on a water to water is higher than a brine system but when you allow for the power of the pump in the well it ends up at roughly the same level. They are also more maintainence intensive than a closed loop.
Personally I'd go for a closed loop if possible.

heavyclay

I too have a similar query. I am about to renovate and extend an old farmhouse and i would like to install a geothermal heating system. I have plenty of space for a ground collector but the ground is very heavy clay. water dose not percolate through the clay. From what i read this is very bad for horizontal array collectors. The farm has an large old unused well (volumn ~ 11 m^3 with a refill rate of 15 liters per hour) currently the overflow goes to a land drain in the field. I would like to use this water in a water to water heat pump, but I would be afraid that if i used it i would freeze the water. (2000 sq ft house aiming to insulate to a high standard)

Has anyone combined a horizontal array with a large water source like this? (pump water from the well to the HP and route it back to the well via a small horizontal array).

Or would it be a better idea just to use a much larger closed loop horizontal array to compensate for the poor soil conditions.

BryanF

heavyclay wrote: »

I too have a similar query. I am about to renovate and extend an old farmhouse and i would like to install a geothermal heating system. I have plenty of space for a ground collector but the ground is very heavy clay. water dose not percolate through the clay. From what i read this is very bad for horizontal array collectors. The farm has an large old unused well (volumn ~ 11 m^3 with a refill rate of 15 liters per hour) currently the overflow goes to a land drain in the field. I would like to use this water in a water to water heat pump, but I would be afraid that if i used it i would freeze the water. (2000 sq ft house aiming to insulate to a high standard)

Has anyone combined a horizontal array with a large water source like this? (pump water from the well to the HP and route it back to the well via a small horizontal array).

Or would it be a better idea just to use a much larger closed loop horizontal array to compensate for the poor soil conditions.

before putting in any HP that's going to work effectively or efficiently, you'd be well advised to try and get your house snug and sealed going as far as MVHR imho. i think Condensers two well option might be better..