Wastewater Heat Recovery Systems (WWHRS)

Highways · 23-03-2015 1:22pm #1

Interested to hear what the consensus is on this emerging technology for Ireland. It's pretty much mainstream in countries like Canada and Holland; even the U.K. is embracing WWHRS with big house builders Barratt Homes specifying it and plumbers merchants like Travis Perkins following suit. The UK's National House Building Council Foundation recently issue a report that concluded WWHRS could help to reduce household CO2 emissions by 7%

hexosan · 23-03-2015 6:32pm

http://passivehouseplus.ie/news/events/see-wastewater-heat-recovery-in-action-at-the-energy-show-in-dublin.html

Anyone got an idea of cost for this system.

BryanF · 24-03-2015 12:44am

Can yee offer some peer reviewed info on this? Ta

hexosan · 24-03-2015 8:08am

BryanF wrote: »

Can yee offer some peer reviewed info on this? Ta

We'll assume you don't approve so

BryanF · 24-03-2015 10:51pm

hexosan wrote: »

We'll assume you don't approve so

Not at all, I'm just skeptical of the % co2 reductions mentioned in the original post.

I'd love to see an independent robust study to put the % co2 savings in context ?

Edit: ie would you be better of reducing fabric heat loss and the requirement to generate heat/ HW instead of trying to recover heat from waste water.

Calahonda52 · 24-03-2015 11:36pm

This is not a recent report but dates from July 2012 and I have attached a copy.
The WWHRS is discussed on page 24 and the 7% comes from the estimated savings on the shower system only.

This, then in the interests of good journalism and quasi-trolling, gets converted into the outrageous claims made by the OP [The UK's National House Building Council Foundation recently issue a report that concluded WWHRS could help to reduce household CO2 emissions by 7%]
who has just read the article in PHP magazine that Hex at least links to.

When I first read this when it came out, the following idea struck me as being mad:
Saving energy used for water heating removes the pressure on developers to optimise building fabric.

Highways · 25-03-2015 12:29am

[SAP listed, WRAS approved, KIWA tested sounds like sound credentials , no?
Optimising the building fabric doesn't stop hot water draining down the shore or reduce the volume required for showering, does it?

quote="Calahonda52;94820167"]This is not a recent report but dates from July 2012 and I have attached a copy.
The WWHRS is discussed on page 24 and the 7% comes from the estimated savings on the shower system only.

This, then in the interests of good journalism and quasi-trolling, gets converted into the outrageous claims made by the OP [The UK's National House Building Council Foundation recently issue a report that concluded WWHRS could help to reduce household CO2 emissions by 7%]
who has just read the article in PHP magazine that Hex at least links to.

When I first read this when it came out, the following idea struck me as being mad:
Saving energy used for water heating removes the pressure on developers to optimise building fabric.[/quote]

Highways · 30-03-2015 1:36pm

Anyone got an idea of cost for this system.[/QUOTE]

Trade prices start at approx €610 + vat for the Recoup Pipe+

BryanF · 30-03-2015 9:05pm

Highways wrote: »

[SAP listed, WRAS approved, KIWA tested sounds like sound credentials , no?
Optimising the building fabric doesn't stop hot water draining down the shore or reduce the volume required for showering, does it?

So can anyone direct me to some peer reviewed studies then.

The Energy hierarchy: Fabric first, reduce energy second, introduce renewables third.

Highways · 31-03-2015 2:19pm

You'll have to put these into your browser as Boards won't let me post links;
Www.aimc4.com/newsdetails.jsp?id=21
Www.aimc4.com/filelibrary/files/AIMC4_How_did_the_Homes_Perfrom-_the_data.pdf

Www.recoupenergysolutions.co.uk/news/
Www.aimc4.com/page.jsp?id=1

Highways · 31-03-2015 5:17pm

Thanks BryanF. Re the energy hierarchy; it could be argued that WWHR belongs in category 1 rather than 3. WWHRS retain upto 68% of the EXISTING heat from your shower-water, not offer a new method of primary water heating. So in the same way better lagging, windows etc. retain the space heat, WWHR retains the water heat contained within the fabric of the building.

Highways · 31-03-2015 5:56pm

That last line more correctly should read "contained within the building envelope". Boards wouldn't let me edit it!

sydthebeat · 31-03-2015 10:41pm

if the hot water is produced by solar collectors, then it sort of makes the technology useless for the times solar already provides sufficient hot water... no?

Highways · 02-04-2015 10:39am

If the homeowner has enough money, storage space and roof space to collect all their hot water demands all year round, then you are correct.
However, with many installations there is not enough roof space, orientation, or costs are too high to do this. At this point, as soon as you become reliant on a secondary back up to meet your requirements then costs can begin to go up. Quite often this could be an electric immersion heater, which can be very expensive.
The other thing is habits – If in a family you shower in the evening and then again in the morning, that is a lot of water being used before the sun has even come up!!
So, from a practical point of view and considering the normal size of installation etc., the combination are actually beneficial to each other. Considering the costs of solar, a little bit extra for a WWHR really isn't much!!

StephenPP · 15-05-2015 12:09pm

Have people had any experience on Waste Water Heat Recovery on this thread or know about all the benefits?

BryanF · 17-05-2015 11:17pm

still waiting for a link to some peer reviewed independent studies. The links posted seem to be product literature, by investors with no verified co2 figures.

Highways · 18-05-2015 11:03am

KIWA certification;
http://www.recoupenergysolutions.co.uk/app/download/5791832026/Recoup+Pipe%2B+HE+Efficiency+Certificate.pdf

KCross · 18-05-2015 11:32am

Highways wrote: »

Anyone got an idea of cost for this system.

Trade prices start at approx €610 + vat for the Recoup Pipe+[/QUOTE]

If you have a renewable energy source like Geothermal or Solar to heat your hot water you have very little cost for heating hot water in the first place. I use quite a bit of hot water with power showers and it costs me about €120/yr to heat my hot water.

If this system costs €700 inc vat to the trade it probably means it will be in excess of a €1000 to the end user because there will also be construction/plumbing work required to retrofit it.

If it provides 60% efficiency that means it would save me €72/yr which would give me a 13 year payback. Hardly a convicing sales pitch and I'd doubt you would actually get the payback in 13 years as a solar user would have alot of "free" water so getting 60% efficiency while you are receiving "free" hot water is saving you nothing so the payback is going to be much longer than 13 years.

Basically, I dont see the benefit based on those figures. Maybe if you were usng expensive immersion heating for your hot water or for an apartment complex but for a single house where renewables are already installed?

BryanF · 18-05-2015 10:51pm

Still waiting. A signature from the product manager is not a peer reviewed study

StephenPP · 19-05-2015 9:25am

Can I recomend looking at AIMC4? This was an independent study on lost of different sustainable products to see the improvements made to a house built to regulations. Conducted by some of the biggest house builders (Barratts, Crest Nicholson, Stuart Milne) its conclusions were that Waste Water Heat Recovery was one of the best performers. All the papers are readily available on AIMC4 website through information papers but I have put a link to our website below and a news article which highlights what has been said.

powerpipehr .co.uk /aimc4-findings-waste-water-heat-recovery-outperforms-sap-calculations/

(says I cannot post websites please close gaps!)

I hope this helps.

KCross · 19-05-2015 11:54am

StephenPP wrote: »

Can I recomend looking at AIMC4? This was an independent study on lost of different sustainable products to see the improvements made to a house built to regulations. Conducted by some of the biggest house builders (Barratts, Crest Nicholson, Stuart Milne) its conclusions were that Waste Water Heat Recovery was one of the best performers. All the papers are readily available on AIMC4 website through information papers but I have put a link to our website below and a news article which highlights what has been said.

powerpipehr .co.uk /aimc4-findings-waste-water-heat-recovery-outperforms-sap-calculations/

(says I cannot post websites please close gaps!)

I hope this helps.

The homeowner cost savings were a little vague to be honest.

http://powerpipehr.co.uk/homeowner-cost-savings/

It says the payback is 5-15 years! Based on my rudimentary calculations in my earlier post, it is the 15years and longer. Thats too long a payback.

While I'm sure the technology works and will save money after it is installed, that isnt enough. It has to make economic sense based on the initial installation costs too and I dont think it does for a domestic scenario where renewables are already being used for heating hot water.

The other case study I saw on the website was for a big commercial scenario which paid for itself in 1 year.... probably true but not applicable to homeowners.

StephenPP · 19-05-2015 12:31pm

There are different factors that need to be taken account of. The average UK household is based on 2.4 people with AIMC4 independently stating that a WWHR unit should save 500 kwh per person per year. This works out at around £20 per person

Another variable is how many people are living at the property therefore and the use of the shower. If you have a family of 4 all showering you could be saving £80 a year but of course if there is only one person at the property who potentially does not shower as much it is going to reduce the saving quite considerably.

The product is cost effective approach to saving on all the hot water you can see going down your drain but it does rely on other factors to have its maximum use realised.

There is also a difference with the Power-Pipe range where there are over 60 units offering different lengths and different efficiencies and therefore different prices. We prefer to work on a project by project basis as each scenario is different.

Pricing is cheaper then I have seen in the forum already at list and discounts available for multiple units being bought.

KCross · 20-05-2015 10:14am

StephenPP wrote: »

Pricing is cheaper then I have seen in the forum already at list and discounts available for multiple units being bought.

Can you give some typical retail prices for the system?
e.g. for an average one off house (4 bed, 2 showers)

StephenPP · 21-05-2015 10:30am

If you take an average house as stated there are a few factors to consider. As there are over 60 units available, it depends if you are looking to meet a certain building regulation or save as much energy as possible. The list price for the units range from the smallest at £275 to the largest at £700.

The most common unit would be around £425.

BryanF · 21-05-2015 11:33am

Stephen it is clear you work for this company. We don't allow advertising here and although I've repeatedly asked neither you nor the op has produced any peer reviewed literature

That was me asking for CE / BBA certs via your work email, and by your response I take it that these products dont have either.

Highways · 21-05-2015 2:57pm

BryanF wrote: »

Still waiting. A signature from the product manager is not a peer reviewed study

KIWA is an independent reputable testing and certification agency; http://www.kiwa.nl/about/ The product manager you refer to is from KIWA, not the product manufacturer Recoup Energy Solutuions.

BaronyOfIda · 24-03-2016 2:33pm

Interesting piece from a few years ago on wastewater heat recovery in The Green Register;
greenregister.org.uk/Wastewater-heat-recovery
Same author has a piece in the current edition of Passive House + magazine encouraging Passive House designers to start specifying wastewater heat recovery into their designs

Wastewater Heat Recovery Systems (WWHRS)

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