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Plumbing & Plumbers Forum - Martinplumber
MartinplumberDiscuss Martinplumber at UK Plumbers Forums; What is the heat loss for the property ? 1000m doesn't sound anywhere near enough based on your description so far. The heat pump is a brilliant solution for a ...
- 18-11-2015 #13
What is the heat loss for the property ? 1000m doesn't sound anywhere near enough based on your description so far.
The heat pump is a brilliant solution for a well insulated property
I'm really concerned that you don't know how to design this and you will end up with a system that just won't work
You need to answer my previous questions before anyone give you any more help..
- 18-11-2015 #14
- Join Date
- Mar 2013
- Thanked 21 Times in 21 Posts
If you have your cylinders at the other end instead, and only a short run of circulating pipework you lose less from the HWS but more from the mains to the cylinders (in this case because of the higher primary temp the losses would go up 50% for the same size pipe) plus you'd need a more powerful primary pump=higher running costs, so you'd probably save very little if anything.
i know the pumped hot water is the way all the designers and suppliers have gone down for such wide spread domestic use but I wonder is it because it's the way they always do it, and nobody seems to questions it, and perhaps because it is less complicated to install? But I keep thinking of all that piping hot water being pumped around even in the best insulated pipe work how it must lose a considerable amount of heat. Consider if you would that probably throughout April - November the underfloor heating in any new built house is not required at all because of the high amount of insulation in all the floor, walls and ceiling etc., which now means you need hardly turn any heating and only a little heating even in the winter months, especially when it is as mild as it has been. Then all the pipe work to the U/f/h here shall be standing idle for all these months, when it could be also used in the heating of the hot water tanks by default on this pipe work to come on each night with the cheaper off peak supply to heat the water tanks? By the way there is a 150 litre buffer tank on the run by the heat pump. The emmersions could then come on for say an hour to top up the hot water to bring the tanks up to 65-70 degrees as required and then around 5am if the underfloor heating were calling for heat using a time switch and room controllers the underfloor heating then opens the valves to those manifolds calling for heat to then warm up the house?
Is this a ridiculous cenario I am contemplating which might be too complicated and risky or is this a better more efficient way of utilising one considerable length of pipe work loop instead of two and a more efficient way of saving electricity with 24 hour pumping and the inevitable heat loss this must to some degree cause? That is what I am trying to decide.
Many thanks again for all your help and input.
Pumped HWS is usual in commercial installations and larger domestic ones where you usually have all the plant in a central plantroom or aren't able to have cylinders near to the main points of use. Also, if you've got sinks or whatever scattered around the building you need circulation unless you are willing to accept lots of water wastage drawing off cold water from long dead legs.
- 18-11-2015 #15
All that's good there are still fundamental issues with Martinplumber's designs though - for example Heatpumps work on a 3 port diverter valve, so where will he put the buffer tank, how / why would you share the flow/return with the 7 heating manifolds.
This is a very straightforward system, being made complicated by the OP, who seems to lack fundamental understanding of heat pumps and plumbing systems and building regulations and MCS requirements and says this is for his own house, and the VERY worrying thing is that he is MCS certified ..
7 LARGE Heating manifolds 3 x 300 litre DHW cylinders, unless this is a passiv haus, (or close to it ) then 1000m can't be any near adequate, unless he got hot rocks... Round here it works out in the order of 100m/kW so that's only 10kW ....
Last edited by Worcester; 18-11-2015 at 08:47 PM.
- 18-11-2015 #16UnregisteredGuest
Many thanks for your help and information which has been very helpful in helping me decide to go with the pumped hot water loop method as was designed. Your figures even off the back of the fag packet are very helpful, combined with the limited pressure loss information of yesterday within the pumping loop has finally sold me on sticking to the method as was designed for the remainder of the system.
Worcester, I do find some of your comments very rude and lacking in respect for your fellow plumbers especially when you know so little of the facts. I didn't know you were going to inspect every avenue of my gshp system, as I was only enquiring whether there was a need to have a circulating pump for the hot water over this distance. You might like to know I am in fact already using the same system as sought with a three port diverter valve and buffer tank installed but to a smaller scale yet still without pumping the hot water whilst heating just 3 manifolds of ufh, the hot water plus three large heat exchangers to a swimming pool in the summer months. The 1000metres of pipe mentioned are coiled slinkies so it's total length of pipe run are nearer to 4000 metres and of a larger bore pipe than from some suppliers, laid flat within 2 acres of south facing land. Plus this gshp system which has cost me over £150,000 is not being installed by a half wit and as I have said has been calculated by professionals who I am happy to take the their figures for the length of slinkies as being adequate for this property. And yes I am MCS approved but nevertheless always willing to learn and never thought I knew it all like some people it seems. Admittedly what I have sought is probably more to do with an electrician than a plumber but nevertheless joined this forum to find out if there was anyone having experience of installing a system over such a distance and in such a way as using two phases of electricity to the best advantage, which obviously you haven't. Your comments are very condescending, disrespectful and do spoil the good work some people who simply write to help others within this forum.
Thank you once again for your help Sparkplug which is very much appreciated.
- 18-11-2015 #17
It was simply that you consistently didn't answer my questions..
Indeed whilst trying to help you not make a very expensive mistake, you completely disregarded them and wouldn't give any facts.
Last edited by Worcester; 18-11-2015 at 11:00 PM.
- 18-11-2015 #18
- Join Date
- Feb 2011
- in the land of make believe, in the county of durham, next best to Yorkshireland
- Thanked 1,572 Times in 1,511 Posts
Ignore Worcesters advise at your peril. Very knowledgeable individual imho.Fly Me To The Moon And Let Me Play Among Stars.............
No I'm not cheap, but I'm happy in my work.
Wouldn't you rather have somebody that's happy working in your house?
- 20-11-2015 #19UnregisteredGuest
Sorry was having a bad day and a bit touchy. in fact I have since checked and its 6600 metres of underground slinkies we have, so should be enough for the domestic side.
Have a good day and apologies again.
- 20-11-2015 #20
Depending upon which heat pump(s) you are using, how they are configured, how the three DHW tanks call for hot water and how the heat pumps are configured to deliver that is critical.
A 150 litre buffer isn't going to be able to supply heat to a house with 7 ufh manifolds for very long at all lwe are talking of only minutes of heat storage there, and there is a danger that the heat pumps are never able to provide heat to the house.
If you are confident that your installer has got all that covered then fine. - It was my concern for you in that area that has been prompting my questions to you.
There is a big difference between 1000 and 6600 meters
- 21-12-2015 #21
- Join Date
- Oct 2007
- Thanked 85 Times in 73 Posts
why don't you fit a stat and a timer to the secondary return no point keeping it on 24/7Beer is the reason I get up every afternoon.
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