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Author Topic: Water Source Heat Pump Project  (Read 11462 times)
nowty
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« Reply #60 on: December 31, 2018, 02:49:39 PM »

Another update.

The heatpump shut down again last night due to cold ground loop temp. sh*tfan
Again the pipes were silted up and the flow temp was around minus 10 giving a layer of ice on the flow pipe. freeze
First time I have seen that. Shocked





A quick pressure wash and now it runs above zero once again. fingers crossed!
I also checked the river temp and its 11 degrees.


« Last Edit: December 31, 2018, 02:51:34 PM by nowty » Logged

11kW+ of PV installed and 54+ MWh generated.
Lithium battery storage of 50+ kWh.
Hot water storage of 15+ kWh.
Heat storage of 15+ kWh.
6kW Ground source heatpump.
EV BMW i3 (another 30+ kWh's of storage).
250,000+ litres of water harvested from underground river.
Home grown Fruit and Veg.
Countrypaul
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« Reply #61 on: December 31, 2018, 03:27:29 PM »

Is it purely silt sticking to the pipes, or is there ice forming on them and holding onto the silt?  Either way you may want to consider putting some sort of alarm/warning somewhere obvious to you, which could be as simple as a a thermostatic switch illuminating a light when the pipe temperature gots close to zero giving you a little time to plan your clean up, rather than finding out after you've had 6 pints (not that you ever would of course  Grin ).
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nowty
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« Reply #62 on: December 31, 2018, 08:58:27 PM »

Is it purely silt sticking to the pipes, or is there ice forming on them and holding onto the silt?  Either way you may want to consider putting some sort of alarm/warning somewhere obvious to you, which could be as simple as a a thermostatic switch illuminating a light when the pipe temperature gots close to zero giving you a little time to plan your clean up, rather than finding out after you've had 6 pints (not that you ever would of course  Grin ).

To be honest I don't know as it was 4:00am and I had just got up to relieve myself and I noticed I could not hear the flow pumps running. I did not look down the hole till the next day as I was half asleep and didn't want to fall down it in the middle of the night. It restarted and was ok for the rest of the night apart from the frosted flow pipe. freeze

If it trips out its in the first few minutes of coming on when the COP level is at the highest and the temperature of the ground loop drops right off rapidly. Once the radiators are up to 30+ degrees the efficiency drops a bit and the ground loop temp always rises a bit so its then ok for the rest of the operating run.

Its only the second time its happened and its about two weeks since so a few seconds of pressure washing once a week should stop it happening in future. I have not got round to installing the remote temp sensor but the priority has obviosly increased so I will try and do it this week. There is an inbuilt temp sensor but its a pain to scroll through the remote control panel. facepalm
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11kW+ of PV installed and 54+ MWh generated.
Lithium battery storage of 50+ kWh.
Hot water storage of 15+ kWh.
Heat storage of 15+ kWh.
6kW Ground source heatpump.
EV BMW i3 (another 30+ kWh's of storage).
250,000+ litres of water harvested from underground river.
Home grown Fruit and Veg.
knighty
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« Reply #63 on: December 31, 2018, 09:42:44 PM »

do the pipes silt up and then clear themselves once there's a good bit of rain?

I think if you could put something big/heavy in the middle of the coil to make the water more turbulent around it, it might solve the problem for you.... the problem is getting something big/heavy down the hole and into the coil :-o


maybe stick a bit of plastic pipe in the hole and see if it silts up in the same way?

you'd need a much longer length but then you could use plastic... not having to de-silt the coils might be a big bonus once you get old?
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nowty
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« Reply #64 on: January 01, 2019, 12:46:57 AM »

Yes all the silt clears out once we have a good rain shower.

There is nothing that can be done to increase the flow or turbulence, the flow is just so weak unless it rains.
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11kW+ of PV installed and 54+ MWh generated.
Lithium battery storage of 50+ kWh.
Hot water storage of 15+ kWh.
Heat storage of 15+ kWh.
6kW Ground source heatpump.
EV BMW i3 (another 30+ kWh's of storage).
250,000+ litres of water harvested from underground river.
Home grown Fruit and Veg.
Nickel2
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« Reply #65 on: January 01, 2019, 07:49:22 AM »

Would it help to slip in lengths of plastic electrical conduit between the turns of the coils to help flow through them? As they are at the moment, tied in bundles, there will tend to be nulls/stagnant areas where water doesn't flow fast enough, so silt would be prone to collection.
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1.140kW mono south-facing at 49*
EpEver 4210A at 24v
24V 400 Ah battery. (4x200Ah FLA)
EpEver STI1000-24-230 pure sine inverter
Of course it'll work. (It hasn't caught fire yet).
nowty
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« Reply #66 on: January 01, 2019, 04:37:29 PM »

Maybe but its difficult to retrofit it now. I did think about doing this when I originally fitted it but, the coils are difficult to pull apart and I would have ended up with taller coils and less coils would have fitted under the water. I was also concerned that gravel might get trapped in the gaps and be difficult to shift. In hindsight I might have been better using 10m long coils instead of 25m long ones, then I could have fitted more of them which would have achieved a similar result.

Anyway it worked ok again last night with flow around zero degrees and return about +4 degrees so at least I know the pressure washing worked.

Its going to be vey sunny for the next couple of days so I might run it in the daytime and take some temperature measurements of the river water after its been ran for an hour. The river water was around 16 degrees back in Sept and now its 11 degrees but I have never measured it after the heatpump has been run for a while. I did some back of fag packet calculations a while ago and reckoned that the heatpump would drop the ambient river temp by about 5 degrees so it will be interesting to find out for real.


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11kW+ of PV installed and 54+ MWh generated.
Lithium battery storage of 50+ kWh.
Hot water storage of 15+ kWh.
Heat storage of 15+ kWh.
6kW Ground source heatpump.
EV BMW i3 (another 30+ kWh's of storage).
250,000+ litres of water harvested from underground river.
Home grown Fruit and Veg.
Westie
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« Reply #67 on: January 01, 2019, 05:40:34 PM »

Would it be possible to create a weir just upstream of the coils so the water would be turbulent?
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4kwp south facing array  SMA 4000TL grid connected.  2x30tube Navitron solar thermal panels (east/west). Arada 5kw S/C WBS. 25000Ltr underground rain water tank. KTM E-Bike  Cool
nowty
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« Reply #68 on: April 15, 2019, 01:11:05 PM »

Project Update,

Over winter the GSHP has been running overnight on E7 but now we are running overnight on batteries (charged previously with solar) and during daytime on solar, backed up by batteries. I only expected that this would happen on the odd few really sunny days, but the high efficiency of the heat pump and my recent Sunny Island Upgrade and large battery integration has made this possible. So I reckon from April to Sept I will be importing hardly any gas. I have forecasted that this has dropped my annual gas import from 23,000kWh down to 13,000kWh, with an annual increase of imported elecy from 700kWh to 2,900kWh.

So overall, annual imported energy is down 7,800 kWh and the house is more comfortable as I am not letting the temp drop much overnight. I could decrease the gas even further with more imported elecy but that would be at an extra cost.

I have also found that if its not been raining for a week or so, all I need to do is simply spray the heat exchanger for a few seconds with a hose pipe from above every few days to keep the insulating silt level down. I dont need to go down the hole, only need to drag the man hole cover back a few inches and point the hosepipe down there.


Edit - Just to add that although imported energy is down 7,800kWh so big reduction in carbon footprint, the pounds cost is almost the same as even E7 rates are 3 times my gas rate so no cost savings at all. Maybe that means that gas is too cheap.
« Last Edit: April 15, 2019, 07:53:54 PM by nowty » Logged

11kW+ of PV installed and 54+ MWh generated.
Lithium battery storage of 50+ kWh.
Hot water storage of 15+ kWh.
Heat storage of 15+ kWh.
6kW Ground source heatpump.
EV BMW i3 (another 30+ kWh's of storage).
250,000+ litres of water harvested from underground river.
Home grown Fruit and Veg.
Nickel2
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« Reply #69 on: April 15, 2019, 02:23:36 PM »

...Or maybe fit a spray-bar running from an electric pump, automated to operate every time the temperature differential gets out of range?
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1.140kW mono south-facing at 49*
EpEver 4210A at 24v
24V 400 Ah battery. (4x200Ah FLA)
EpEver STI1000-24-230 pure sine inverter
Of course it'll work. (It hasn't caught fire yet).
nowty
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Posts: 749



« Reply #70 on: June 13, 2019, 05:10:18 PM »

Project Update,

The system has been running on solar PV and / or batteries for several months now, no imported elecy or gas required at nowty towers at all. extrahappy

But I ran into a problem a couple of weeks ago.

I noticed the ground loop was running very cold of late, like the middle of winter, below zero at times even though the river water temperature is now around 15 degrees.
Then the other day it kept shutting down due to cold ground loop, even after I had given the river heat exchanger a good rinse off. help

Anyway, I soon found the fault, both my ground loop water pumps had failed. I guess one had failed some time ago and I had not noticed. sh*tfan

Luckily I had bought a couple of spares so was back in operation in no time. My external fitting of the pumps meant a very easy swap over. fingers crossed!

I think they have failed due to condensation. The pumps are installed upside down and lots of condensed water dripped down into the bit which houses the electrics. I then read the pump manual and it says you cannot pump fluids at a lower temp than ambient because of condensation issues. Hmmmmm, maybe I should read the instructions properly first. facepalm

I have now wrapped the pumps in insulation so they stay cold and this seems to have stopped the condensation so hopefully they will be ok. whistlie
If not I will have to change them for another type.
Logged

11kW+ of PV installed and 54+ MWh generated.
Lithium battery storage of 50+ kWh.
Hot water storage of 15+ kWh.
Heat storage of 15+ kWh.
6kW Ground source heatpump.
EV BMW i3 (another 30+ kWh's of storage).
250,000+ litres of water harvested from underground river.
Home grown Fruit and Veg.
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