GSHP poorly sick

[jrinns]

Yes any updates, have companies coming out in the next few weeks to discuss GSHP or Biomass Boiler.

Anyone share their experiences?

J

[Rickyy]

I've only just come across this thread and I'm shocked!

I'm a Plumber by trade and I did a course at Worcester Bosch HQ a few years ago on GSHPs. I haven't done anything with them out in the wild since that course, so I only know what I learnt from the classroom. But fk me, the rule was, no joints if possible and if a joint was used, it was to have an inspection chamber placed over it!

I also remember the design of the ground loop being crucial to the performance. I wouldn't feel confident designing one, so why a group of builders felt they could do it is beyond me!

[p1esk]

Throttle Body said:

I've just discovered this topic. What a story! My new house is nearing completion. At the planning stage, I was very keen to install GSHP, but the builder was not impressed (it was outside his comfort zone). In the end, the site didn't allow for the ground arrays because of the number of trees, and the lack of open ground - you do need a big open area for these things.

Anyway, having read your story, I am quite happy to have connected the boiler to the mains gas supply. The construction industry seems to have a way to go before it has the skills to install such new-fangled things as heat pumps.

Heat pumps aren't really new-fangled though, because I seem to recall them being talked about in the 1960s. At that time they did sound to be a very attractive proposition, but I never heard of any actual installations, presumably because they were difficult things to design and install well enough to actually deliver the benefits reliably.

It rather looks as if that is still the case.

[p1esk]

jrinns said:

Yes any updates, have companies coming out in the next few weeks to discuss GSHP or Biomass Boiler.

Anyone share their experiences?

J

No actual experience personally, but

a) heat pumps can be difficult to get right, and
b) biomass boilers seem to have been unreliable too, in some cases.

I have recently been quite interested in both of those options, but at the moment I'm inclined to stick with a boiler running on mains gas (which we have, fortunately) and a combination of radiators (where we have solid floors), and UFH where we have suspended timber floors, plus doing the best we can with insulation and the minimising of heat losses.

It's not very adventurous and sophisticated, but at least it should work.

[p1esk]

Rickyy said:

I've only just come across this thread and I'm shocked!

I'm a Plumber by trade and I did a course at Worcester Bosch HQ a few years ago on GSHPs. I haven't done anything with them out in the wild since that course, so I only know what I learnt from the classroom. But fk me, the rule was, no joints if possible and if a joint was used, it was to have an inspection chamber placed over it!

I also remember the design of the ground loop being crucial to the performance. I wouldn't feel confident designing one, so why a group of builders felt they could do it is beyond me!

Hiya, Rick,

The system originally installed for cogcog seems to have included (in effect) six panel 'radiators' buried in the ground, all linked together with pipework as the means of collecting ground heat. That surprised me as I'd always imagined the buried part of a GSHP to be merely a serpentine arrangement of pipes, all with butt welded joints, and as such I would have expected that to be completely reliable. Is there some reason why it isn't done that way?

Best wishes all,
Dave.

[Rickyy]

p1esk said:

Rickyy said:

I've only just come across this thread and I'm shocked!

I'm a Plumber by trade and I did a course at Worcester Bosch HQ a few years ago on GSHPs. I haven't done anything with them out in the wild since that course, so I only know what I learnt from the classroom. But fk me, the rule was, no joints if possible and if a joint was used, it was to have an inspection chamber placed over it!

I also remember the design of the ground loop being crucial to the performance. I wouldn't feel confident designing one, so why a group of builders felt they could do it is beyond me!

Hiya, Rick,

The system originally installed for cogcog seems to have included (in effect) six panel 'radiators' buried in the ground, all linked together with pipework as the means of collecting ground heat. That surprised me as I'd always imagined the buried part of a GSHP to be merely a serpentine arrangement of pipes, all with butt welded joints, and as such I would have expected that to be completely reliable. Is there some reason why it isn't done that way?

Best wishes all,
Dave.

Not heard of that method! The two methods I was taught were, borehole and laying pipe horizontally in trenches ~1M below ground level. Ideally with a continuous length of pipe, with inspection chambers over any joints.

It was probably around 4 years ago I did that course, so can't remember much about it.

[p1esk]

Rickyy said:

p1esk said:

Rickyy said:

I've only just come across this thread and I'm shocked!

I'm a Plumber by trade and I did a course at Worcester Bosch HQ a few years ago on GSHPs. I haven't done anything with them out in the wild since that course, so I only know what I learnt from the classroom. But fk me, the rule was, no joints if possible and if a joint was used, it was to have an inspection chamber placed over it!

I also remember the design of the ground loop being crucial to the performance. I wouldn't feel confident designing one, so why a group of builders felt they could do it is beyond me!

Hiya, Rick,

The system originally installed for cogcog seems to have included (in effect) six panel 'radiators' buried in the ground, all linked together with pipework as the means of collecting ground heat. That surprised me as I'd always imagined the buried part of a GSHP to be merely a serpentine arrangement of pipes, all with butt welded joints, and as such I would have expected that to be completely reliable. Is there some reason why it isn't done that way?

Best wishes all,
Dave.

Not heard of that method! The two methods I was taught were, borehole and laying pipe horizontally in trenches ~1M below ground level. Ideally with a continuous length of pipe, with inspection chambers over any joints.

It was probably around 4 years ago I did that course, so can't remember much about it.

OK, I'm not in a position to dispute what you say, but here's a few thoughts:

I would say that if we're going to have something buried in the ground, something that is supposed to work reliably for us over a long period of time, and not need servicing and maintenance, we need to be pretty sure of what we're doing.

In that case, buried pipework (or whatever it is) needs to be of a suitably durable material, e.g. free from corrosion etc., and free from trouble spots like joints that might leak. To me that suggest the need for pipework, if that's what it is, that can be deployed in suitably long lengths without joints, as is done with UFH or, if there need to be underground joints, they should be welded. At this point I'm assuming that steel piping is used.

So far as inspection chambers are concerned, is that a satisfactory answer? It is my understanding that the ground loop of a GSHP system should be buried at a considerable depth, like four feet or more, in which case an inspection chamber over each joint doesn't sound to be of much help.

Bear in mind that you don't need just an inspection chamber, so that you can see if the joint is leaking. You need sufficient access to be able to get at it and repair it if it is leaking, and an inspection chamber will not give you that ability, because the joint will be out of reach. You might be able to see it, but you can't get at it to repair it, you wouldn't be able to reach it from ground level. If a joint is leaking, you will need space around it so that you can actually get at it and carry out the necessary work, and that would require a much larger hole in the gound than merely an inspection chamber.

[Rickyy]

I say inspection chamber , but what I mean is something like a large manhole cover, so you could reach down and repair a leaky joint. That's certainly what I'd insist on if it were a job of mine.

[p1esk]

Rickyy said:

I say inspection chamber , but what I mean is something like a large manhole cover, so you could reach down and repair a leaky joint. That's certainly what I'd insist on if it were a job of mine.

Yes, I know what you're saying, but at four feet down (if that's the sort of depth at which the pipework is buried) I doubt if you could carry out a repair by just reaching down the manhole, so to speak. At any rate, if I were designing the system I wouldn't want to arrange things that way.

Heat pumps still seem to be an attractive proposition, but I wonder if their application is being hampered because there are insufficient companies with the expertise to design and construct installations that perform well, and are reliable. It may be that too many installations are failing to live up to expectations, and giving rise to bad publicity.

[Rickyy]

p1esk said:

Rickyy said:

I say inspection chamber , but what I mean is something like a large manhole cover, so you could reach down and repair a leaky joint. That's certainly what I'd insist on if it were a job of mine.

Yes, I know what you're saying, but at four feet down (if that's the sort of depth at which the pipework is buried) I doubt if you could carry out a repair by just reaching down the manhole, so to speak. At any rate, if I were designing the system I wouldn't want to arrange things that way.

Heat pumps still seem to be an attractive proposition, but I wonder if their application is being hampered because there are insufficient companies with the expertise to design and construct installations that perform well, and are reliable. It may be that too many installations are failing to live up to expectations, and giving rise to bad publicity.

That is the main issue as you say. The systems do need to be designed by someone who knows what they are doing and by someone with the correct insurance in place to cover any cockups!

I'd have no worries about designing and installing the heating system (maybe some guidance on the UFH layouts), but I wouldn't dream of designing the ground loop. So much to the point that I'd not want anything to do with it's design or installation, except to make the final connections to the heat pump.

Worcester Bosch will actually provide a design service for the system, I'm sure many other manufacturers would too. I'd love to do some work on the systems, but there doesn't seem to be many of them about and those that are about, are maintained by big firms.

[C Lee Farquar]

p1esk said:

Heat pumps still seem to be an attractive proposition, but I wonder if their application is being hampered because there are insufficient companies with the expertise to design and construct installations that perform well, and are reliable. It may be that too many installations are failing to live up to expectations, and giving rise to bad publicity.

One of my customers has a mobile drilling rig as part of his Company, they do holes for vertical GSHP when people are tight on space and boreholes.

He's just had heating installed in his workshops and office... biomass. I'm sure the subsidy for biomass helps but he could have bored the holes for the cost of the diesel and still didn't chose a GSHP.

[JM]

p1esk said:

OK, I'm not in a position to dispute what you say, but here's a few thoughts:

I would say that if we're going to have something buried in the ground, something that is supposed to work reliably for us over a long period of time, and not need servicing and maintenance, we need to be pretty sure of what we're doing.

In that case, buried pipework (or whatever it is) needs to be of a suitably durable material, e.g. free from corrosion etc., and free from trouble spots like joints that might leak. To me that suggest the need for pipework, if that's what it is, that can be deployed in suitably long lengths without joints, as is done with UFH or, if there need to be underground joints, they should be welded. At this point I'm assuming that steel piping is used.

So far as inspection chambers are concerned, is that a satisfactory answer? It is my understanding that the ground loop of a GSHP system should be buried at a considerable depth, like four feet or more, in which case an inspection chamber over each joint doesn't sound to be of much help.

Bear in mind that you don't need just an inspection chamber, so that you can see if the joint is leaking. You need sufficient access to be able to get at it and repair it if it is leaking, and an inspection chamber will not give you that ability, because the joint will be out of reach. You might be able to see it, but you can't get at it to repair it, you wouldn't be able to reach it from ground level. If a joint is leaking, you will need space around it so that you can actually get at it and carry out the necessary work, and that would require a much larger hole in the gound than merely an inspection chamber.

It's normally plastic pipe used in the ground loops, there are three different ways of doing this.

1) Laying out dozens of meters of pipe in trenches over a large area.
2) A bore hole or two.
3) A 'slinky' pipe in a ground trench which is similar to 1) but needs less space.

As said no joints unless at an access point, normally at a manifold where the loops join together for the main flow-return. No sharp bends and the pipes should be on a suitable sand type media before trenches are back-filled and no rocks etc near the pipes.

The depth of trenches and boreholes etc will depend on the duty of the heat-pump at least as importantly the geology of the site and the level of the water table etc.