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Shower Heat Recovery


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Some local schools around here have Chinese (Mandarin usually) on the standard curriculum now.  There was a bit of the local news where several youngsters were interviewed and they all had the view that of all the language choices they had at school, learning Mandarin Chinese was seen as being the most useful.

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I remember in the 80's that business people where being taught Japanese, as that was the future then.

I find raising my voice and tone and pointing more vigorously works.

 

If we had to learn a language, why not International Sign Language.  Being a rusty British Sign Language signer, I find it very useful.  I can eves drop at a distance :D

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39 minutes ago, Onoff said:

Could you run a waste pipe through say a compost pile to encourage activity within the pile during the winter months? 

Great idea I will divert the shower run off through our daughters bedroom - that is something of a s heap, she does not live here anymore but she us coming over to see her mum later maybe I can encourage her to tidy it up. 

Edited by MikeSharp01
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On 10/03/2018 at 18:10, JSHarris said:

The problem doesn't exist if you use a bath - just leave it to cool before emptying it and you recover most of the heat back into the house.

 

That awful phrase "think outside the box" was invented for this very occasion!

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5 hours ago, richi said:

That awful phrase "think outside the box" was invented for this very occasion!

When I did my teacher training, a book called 'Inside the black box' was often quoted.  I said, in my usual deadpan way, 'what box' and some of the teacher's teachers though that funny.

Like law, a good monkey could learn the skills needed to practice.

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On 3/10/2018 at 21:42, Nickfromwales said:

You wouldn't possibly be having a Sunamp PV if you have an ASHP ;). You'd maybe instead be going for a Sunamp dual port that takes in wet heat as well as PV based electricity. That way you'd maximise the efficiency of feeding it with heat energy when the PV isn't up to it.

Far less parts and complexity too, that all said bearing in mind that Jeremy has the flagship model and the available range of Sunamp units has grown significantly of late.

 

I was just talking to Andy in SunAmp about this very thing today! He recommended living in the house for 6-12 months (including 1 winter!) with just the Sunamp (Gen3) , PV and off peak electricity and see how I get on and add a high temp ASHP later if I need it. I like this evidence based approach. I can plumb/wire for an ASHP during the build and give myself that option.

 

I'm currently finishing the floor plans so wanted to figure out where things could go and the potential footprint mainly. He recommended locating the Sunamp as close to the manifold and ASHP as possible as I won't have underfloor heating upstairs. I'm building passive so simplifying the heating system and using PCM would be high on my wish list.....

 

I'll be interested to see if my final DEAP / PHPP figures influence the solution, I plan to have 2-3 occupants, 108 sq meter house. I'll be honest the solution compared to oil/gas boilers is strange to me but looking forward to trying it out someday!

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2 hours ago, mike2016 said:

 

I was just talking to Andy in SunAmp about this very thing today! He recommended living in the house for 6-12 months (including 1 winter!) with just the Sunamp (Gen3) , PV and off peak electricity and see how I get on and add a high temp ASHP later if I need it. I like this evidence based approach. I can plumb/wire for an ASHP during the build and give myself that option.

 

I'm currently finishing the floor plans so wanted to figure out where things could go and the potential footprint mainly. He recommended locating the Sunamp as close to the manifold and ASHP as possible as I won't have underfloor heating upstairs. I'm building passive so simplifying the heating system and using PCM would be high on my wish list.....

 

I'll be interested to see if my final DEAP / PHPP figures influence the solution, I plan to have 2-3 occupants, 108 sq meter house. I'll be honest the solution compared to oil/gas boilers is strange to me but looking forward to trying it out someday!

I'm currently spec'ing two installs exactly as you've described. I'm doubling up first as last though as a 'single box solution' offers zero redundancy. 

I'd say save the money of ducting and pulling insulated ASHP pipework ( not cheap stuff to fit and then not use ) and look at keeping sufficient redundant space for a second Sunamp unit ;).

These struggle a bit first getting the house to ambient, but after that they should perform exceptionally well, for as 'passive standard' usually means little and often for space heating and a correctly sized bulk for chunks of DHW.

 

The good thing about the 3rd gen units is the near linear input of energy, e.g. 3kw of electricity input to a 9kw unit needs only ~3 hours to fully recover from a FULLY discharged state.

Best to do as I have and design in some redundancy so you can cope with guest / high use of DHW. ( Space heating is a mere burp as far as these are concerned so focus closely on DHW capacity ). 

The 3g units have two pairs of 'flow and return' connections ( 2 x heat exchangers ) so space heating ( not potable ) and DHW ( potable ) can both be drawn from the same unit but always remain hydraulically separated.

Another good point to make is that either heat exchanger can consume the entire stored energy of the unit, so a 9 kw unit with 2 heat exchangers doesn't offer 2 x 4.5kw 'sides', it can give all 9kw to the space heating HE OR all 9kw to the DHW HE. Tidy :)

As it has no internal pumps and controls etc, compared to the quite complex SAPV unit, you can inject heat energy near linear to consumption, which makes these a very versatile solution. 

Im suitably impressed so far, and Andys advice to run one unit and see how it goes is pretty much the benchmark you shouid observe. There is little useful case study to date so seeking advice is unfortunately the only measure you can practically observe.  

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  • 2 weeks later...

Just spotted this on Ebay: https://www.ebay.co.uk/itm/Zypho-Shower-Waste-Water-Heat-Recovery-Unit-Ref-Z8DWPT3-/222784960687?clk_rvr_id=1477658349340&rmvSB=true

 

I've checked out the manufacturer, Zypho, and although the efficiency isn't great, the units look like they are easy to fit and reasonably affordable.  If retrofitting to an existing installation, then this unit looks a better bet, as it accepts a 40mm inlet and outlet pipe and is under 500mm long: https://www.zypho.eu/products/zypho-izi/

 

Payback periods look reasonable, too.

 

 

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24 minutes ago, JSHarris said:

the major "problem" with that is it does not accept a 40mm input allowing you to keep the existing wet wall shower trap that is installed.  It looks to want to replace the shower trap and it's too late for that now.

 

I similar thing with 40mm in and 40mm out would be quite easy to retrospectively fit to our existing run of shower waste pipes.

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15 minutes ago, ProDave said:

the major "problem" with that is it does not accept a 40mm input allowing you to keep the existing wet wall shower trap that is installed.  It looks to want to replace the shower trap and it's too late for that now.

 

I similar thing with 40mm in and 40mm out would be quite easy to retrospectively fit to our existing run of shower waste pipes.

 

 

Which is why I linked to the other model in that post that does have a 40mm inlet and outlet: https://www.zypho.eu/products/zypho-izi/

 

image.png.567f68b640e90e01b7d3cc4f3f47e5b2.png

 

I've found an Irish supplier, but they want €243 for it, and a UK supplier, but they want £800 for it......................

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That would do.

 

At the moment I have separate 40mm wastes from each shower to the stack (my philosophy to only have a single item on each "small" pipe) so that would either mean 2 of them, or combine the 2 showers onto one 40mm waste.

 

I am actually more inclined to try and find a length of 40mm copper pipe, some 10mm annealled copper coil, and get soldering......

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1 hour ago, JSHarris said:

Just spotted this on Ebay: https://www.ebay.co.uk/itm/Zypho-Shower-Waste-Water-Heat-Recovery-Unit-Ref-Z8DWPT3-/222784960687?clk_rvr_id=1477658349340&rmvSB=true

 

I've checked out the manufacturer, Zypho, and although the efficiency isn't great, the units look like they are easy to fit and reasonably affordable.  If retrofitting to an existing installation, then this unit looks a better bet, as it accepts a 40mm inlet and outlet pipe and is under 500mm long: https://www.zypho.eu/products/zypho-izi/

 

Payback periods look reasonable, too.

 

 

 

That is inexpensive enough that I might try one in a house that is going to struggle on its EPC in a few years.

 

Can anyone advise on what features are required in the gas or electric shower if any, and the practical difference for the user when controlling the shower?

 

Does it make the water warmer at a lower setting on the dial compared to a system without a HR device installed? SO that the experience is the same but the shower is just turned down a little lower on the dial ? Presumably on a thermostatic controller the shower just modulates down the input power required.

 

Assuming showers costing 28p each and a 25% energy saving the simple payback period is about 2000 showers on a cost of £140, or 3000 showers if you pay £70 to fit it.

 

From Romania and 40ukp charge. Hmmm.

 

Thanks for any comments.

 

Ferdinand

 

 

 

Edited by Ferdinand
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I'd say it definitely needs a thermostatic shower to work, as it's going to take a few minutes to heat up and during that time the "cold" water feed to the mixer will change in temperature a fair bit.  A thermostatic shower should compensate for that change with no adjustment needed to the shower temperature.

 

You can buy them from Ireland for €243 from here, not sure of the shipping cost: https://www.greentherm.ie/product-category/energy_efficiency_upgrades/waste-heat-recovery/

 

Or HeatraeSadia stockists sell the same unit here for about £800: https://www.heatraesadia.com/products/renewables/waste-water-heat-recovery/megaflo-horizontal-izi-shower-heat-recovery-unit

 

(yes, rip-off UK is seemingly alive and well...................)

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4 minutes ago, Ferdinand said:

SO that looks to be complication-free using this with gas, then? PRovided the shower is thermostatic.

 

F

 

 

 

Yes, should be.  AFAICS, the main issues are sourcing them at a fair price (the Heatrae Sadia price is just very silly, and the Greentherm price isn't much better) and the fact that they do need annual cleaning.  The latter seems easy - they recommend a standard bathroom cleaner like Mr Muscle plus the long narrow brush they can supply.

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Don't like the idea of the shower waste being reduced for that run. I will have a look at available pipe sizes. But a nice simple idea.

 

He has plumbed the heat recovery into the feed to the hot water tank. I think it would be better to connect it to the cold water feed to the shower thermal mixer valve?

 

 

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2 minutes ago, ProDave said:

Don't like the idea of the shower waste being reduced for that run. I will have a look at available pipe sizes. But a nice simple idea.

 

 

 

 

Standard UK copper pipe comes in 42mm OD and 54mm OD sizes, which wouldn't be a restriction over 40mm PVC/ABS waste pipe.

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2 minutes ago, JSHarris said:

 

 

Standard UK copper pipe comes in 42mm OD and 54mm OD sizes, which wouldn't be a restriction over 40mm PVC/ABS waste pipe.

Thanks. I will go and cost it up.

 

This might have to be well and truly hidden and not mentioned for BC sign off.

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A quick costing on ebay (almost certainly not the cheapest) and it comes out at £167 for a 1 metre long copper 42/54mm heat exchanger for the pipe and all fittings.

 

If I could get that down to £100 I might give it a go.

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