Indeed. If the primaries are not big enough to carry the heat into the property, heat loss due to poor insulation is the last of your worries as there may be insufficient heat flowing in the first place.
Are you going to replace with 28mm or 35mm copper, and properly insulate?
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Others have pointed out lots already and yet your installer claimed that he did a great job!
In order of horror level
@majordennisbloodnok ‘ s spot of totally inadequate pipe size! Especially given the size of ashp!
then rodent ingress opportunity
then not vibration isolation nor insulation to the wall
then lack of insulation to air around the bend
A great example of putting lipstick on a pig/ whatever phrase springs to mind. Just so untidy, slapdash and shows zero understanding of what matters, but just cover it up.
@editor now you’ve done the HG module on flows what size pipe should have been used on your ashp, and what is the maximum heat which would flow through the minuscule ones fitted?
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I've been trying to find a demonstration of the pressure loss which occurs when water passes through a tight bend.
There are loads of YouTube videos which explain the phenomenon at degree level, supported by copious calculations. However, I think the following 3-minute clip, narrated by a hands-on tradesman, is at the right level for most householders to appreciate:
In order of pressure-loss the following hierarchy gives us a good rule-of-thumb for changing the direction in which water flows through a right-angle
90° elbow bend
90° swept bend
a pair of 45° bends, spaced at least 4 pipe-diameters apart
a flexi-pipe, such as commonly used for the final 50cm connection at the rear of an ASHP
a pipe formed using a mechanical bender, thereby using no 'fittings'
a PEX pipe, bent into shape by hand
The order of that list can be amended, depending on the actual situation. But I hope it provides a starting-point from which householders can assess the efficiency of the pipework in a heat-pump installation.
@majordennisbloodnok ‘ s spot of totally inadequate pipe size! Especially given the size of ashp!
...
I'd love to take credit but I think it was @bontwoody. No disagreement with the ordering, though, @judith.
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Indeed. If the primaries are not big enough to carry the heat into the property, heat loss due to poor insulation is the last of your worries as there may be insufficient heat flowing in the first place.
Are you going to replace with 28mm or 35mm copper, and properly insulate?
Mars currently has a GES Caernarfon 18kW ASHP.
The data sheet (Caernarfon) shows approximately 14kW of heat energy at multiple points, including -4°C. At DT5, this would result in a mass flow rate of 2400 litres per hour. A 28mm John Guest plastic pipe can't handle that flow rate without exceeding 300 Pa/m. Neither can the DN32 plastic underground pipework that the plastic pipe is fitted to.
So, we have a bit of a conundrum regarding the best plan of attack here. I think we will be designing a hybrid system and some clever DT work internally to get this all operating as it should. Not ideal, however, we don't have many options here.
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... please explain why running TWO pipes in parallel isn't a possible solution.
I think we are at a point where Mars doesn't want 25 meters of driveway dug back up. Its going to be bad enough digging up each end to fix the terminations (where the pipework in the ground hasn't been fitted/insulated properly). So we are kinda stuck with DN32 (26.5mm internal bore) plastic pipework. My inital calculations are suggesting we can get 10kW down it happily enough. Anything more than this and we are going outside of good hydronic design practices, which I am not willing to do.
As for doubling up pipework, it might give you more flow and reduce presure drops, but you are just adding to copper cost, wall space and visually it would look really poor.
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We are yet to do a heat loss calculation, but I'm currently 'assuming' the house will need this and possibly a bit more.
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We've never had a proper heat loss calculation, James. Our only one was seven years ago with a rep from GES, back when we were new to heat pumps.
The rep proposed an 18kW unit (which was the largest they had) but the story gets worse. The only document he provided calculated our actual heat loss at, wait for it, 50.6 kW.
To be clear, our heat loss is absolutely not over 50kW. This huge discrepancy perfectly encapsulates the state of the industry at the time, and I'm not convinced it's improved much since given what we regularly seem on the forums.
Our next step is to get a correct heat loss calc, and we're arranging for someone to visit us, and to get the process started properly.
And our heat pump is not even close to be being 18kW at sub-zero, so it's going to be hugely insightful to see what unit we end up with.
The rep proposed an 18kW unit (which was the largest they had) but the story gets worse. The only document he provided calculated our actual heat loss at, wait for it, 50.6 kW.
Wow, What planet was he on (obviously one with a much colder climate!)
it's going to be hugely insightful to see what unit we end up with.
Our next step is to get a correct heat loss calc,
Im sure you don't need me to remind you about my experience with heat loss surveys, GIGO definitely applied as I have said on many occasions.
Have you got any data which might allow you to sense check. Given the problems with pipe size etc this is going to be a more important parameter even than 'normal', you need to be as certain as is humanly possible.
This whole process is going to be fascinating, albeit Im sure distressing and stressful for you.
it begs the question whether relocation is an option ...
I doubt it.
The Flights to Rwanda programme was scrapped by the Government last year.
But it's certainly worthwhile noting that Rwanda has far fewer complaints regarding heat-pump installations than Britain. Perhaps MCS would consider a fact-finding mission to discover why.
