Tag Archives: heat exchange

Some more Thermodynamic panel info

Posted on by

From a discussion on http://www.greenbuildingforum.co.uk/forum114/comments.php?DiscussionID=9511&page=1#Item_15

Gary

I consider these as a form of air source heat pump, without a fan or finned coils. The underlying technology is well established and should be as reliable as a GSHP.

The panels are a good solution for a marine environment – I wouldn’t use ASHP units near the sea as the coils rot after about 7 years due to salt corrosion, so they would be a cheaper alternative than GSHP for such areas.

I have seen a completed installation and the owners were very happy with it.

Solar thermal it ain’t however – there is an improvement in COP when the sun is shining but it won’t provide free energy.

Chris

As far as I can find there are two manufacturers of these systems, the best known being Energie in Portugal http://www.energie.pt/ but also a company called Energy Panel in Spain. http://www.energypanel.es/productos.aspx?idFamilia=1&idProducto=1

The problem I have with them is a seeming lack of independent verification of their claims for running costs. I’ve seen mention of various installations being independently monitored but all my previous efforts to get these reports have so far failed.

Does anyone know of any such independent verification?

Some updated Thermodynamic heating system info

Posted on by

I’ve come across the GreenServeUK website with new info on the Thermodynamic Panels.

There’s a big FAQ at http://www.greenserveuk.com/faq/

How it works from http://www.greenserveuk.com/thermodynamics/how-they-work/

Step One

The environmentally friendly refrigerant liquid is fed into the veins of the solar collector.

This refrigerant (R134A) has a boiling temperature of -25°C. The panel absorbs the heat from the environment and raises the temperature of the refrigerant.

The liquid absorbs the heat and it vaporises into a gas which increases the pressure.

Thermodynamic Panel Dimensions are h 800mm, l 2000mm, D 20m.
Each panel is about 8 kg.

Step Two

The hot gas is then passed through a compressor where the pressure causes it to heat further.

Step Three

The heated gas is then passed into the heat exchanger where the heat is transferred into the water cylinder.

Step Four

The cooling gas then passes through a valve reverting back into a liquid where it runs back into the panel where the process begins again.

The system is a solar domestic hot water system in which the solar loop operates on a similar principle of a heat pump.

It is composed of:-

  • An unglazed heat absorber  (1) with 3.20 m2 total aperture area.
  • An insulated,  hot water thermal store (200 l) (2)
  • A  thermoblock, which comprises the electrical powered compressor (5), the thermostatic expansion valve (7), the electrical heating element (4) and the controller.
  • Heat transfer fluid (refrigerant R134a)

The heat transfer fluid in the solar loop is the refrigerant R134a.

The refrigerant is passing through the absorber and evaporates while collecting energy from the surroundings.

The evaporated refrigerant is sucked by the compressor which raises the pressure.

In the condenser, which is integrated as an immersed solar-loop heat exchanger in the lower part of the store, the refrigerant condenses while transferring its condensing heat to the domestic water in the store.

Before the refrigerant is returning to the absorber, a thermostatic expansion valve is reducing the pressure.

An electrical heating element is located in the lower part of the store at the height of the solar-loop heat for use in emergencies and for the anti-legionnaires system.

The magnesium anode (8) or sacrificial anode will extend the life of the tank.

 

Thermodynamic installed at Maidstone UTD Football Club

Posted on by

Just got this press release:

Thermodynamic installed at Maidstone UTD FC…
Project: Maidstone United Football Club – Gallagher Stadium
Client: Graham
Contractor: Gallagher / Greenheat

Thermogroup UK recently supplied two Thermodynamic systems, an Eco 2000 and an SB 24 to meet 100% of the hot water demand for showers and underfloor heating at the new home of Maidstone United FC.

MUFC were attracted to Thermodynamic because of the environmental factor and the potential savings possible against the originally specified electric heating system.

Thermodynamic panels at maidstone united

 

It was estimated that a 24 panel system, to provide underfloor heating to the clubhouse, would use a minimum load of 4.2kW of electricity. Based on this figure and assuming the system is used for an average of 5 hours a day, it is estimated that the SB 24 at MUFC will cost £2.10 per day or £766 per year to run (at £0.10/kW per hour).

The SB24 at MUFC is expected to have a payback of around 5.5 years and bring about an annual saving of £3000 when compared to the electric system that was originally specified.

Please note: The figures in this email are estimates only and we are in the process of installing energy monitors at MUFC to track the exact running costs, savings and payback period.

Thanks for taking the time to read this email and look out for the next Hot News delivered to your inbox. Please consider adding this email address to your safe senders list to ensure you receive all of our communications.

Hot Water Heat Recovery Options

Posted on by

It looks like there is a new player in the UK market. OR one that I’d not previously spotted!

They have a good few shower tray / under shower options and those that can be more centrally integrated into your whole property hot water system.

From http://www.recoupenergysolutions.co.uk/our-range/recoup-retrofit/:

Our most popular waste water heat recovery system due to it’s great efficiencies, low price and superb all round performance. Ideal for new build applications, this product is sure to deliver results, whatever your criteria.


 Recoup Tray+

Our tray is the perfect solution for apartments or ground floor en-suites. Achieving code in city apartments without renewables is notoriously difficult; this shower heat recovery system with flexible tray size is the answer that doesn’t cost the earth.

Building a wet room or have access issues? The Recoup Drain+ provides a great option. Finished in stainless steel and offering 50% efficiencies, this is a must have system for your self build or walk-in shower.

This compact WWHRS is easy to install, easy on the pocket and easy to maintain! As it’s name suggests, it’s ideal for retro-fitting in domestic and commercial properties. A very cost effective way to achieve efficiencies of up to 22%.

A system with great efficiencies specifically designed for large developments with good water pressure. This single walled exchanger provides up to 68% efficiency, so will tick a box for the Technical Director or architect looking for a cost effective solution to achieve code.

Construction (embodied) Energy Vs Operational Energy

Posted on by

My Summary / Conclusion

  • In 2007, 16% of CO2 equiv impact is construction of a building, 84% is operational / in-use.
  • Today the split is roughly 20% embodied and 80% operational.
  • The modelling shows that we are moving to a CO2eq (CO2 equivalent) of 38/62% for masonry construction, and 35/65% for timber-frame construction.
  • No significant differences emerged between masonry and timber construction in terms of overall CO2 impact over the 60- and 120-year study periods. The largest difference observed between comparable masonry and timber constructions was 4%.
  • No clear / significant impact of thermal mass.
  • Emissions are cumulative, so 1 tonne of CO2 equiv at the point of construction roughly equals a tonne of CO2 equiv during the 60 year life of a building.

Which aspects of a dwelling are responsible for the largest CO2 impact?

  • Space and water heating have the largest CO2 impact in dwellings.
  • Appliances also have a large operational CO2 impact.
  • In both masonry and timber constructions, the impact of foundations and ground floors dominates the embodied CO2eq impact.
  • In masonry construction, the external walls also have a major impact.
  • Other elements, such as windows/doors and floor finishes, have a relatively large impact because they are repeatedly replaced throughout the life of the dwelling.
    • Waste water heat recovery systems have a 60 year assumed life span (windows and doors – 40, MVHR 15, flooring 10 ….)
  • The embodied impact of services was found to be approximately 5% of impact at 60 years and 7% at 120 years.

Construction Vs Operational Energy

I’ve come across some interesting figures and links to research in an article in the Green Building Magazine (by www.greenbuildingpress.co.uk).

  • Embodied Energy – a ticking time bomb (Spring 2012)

In 2007, around 16% of the CO2 equivalence impact was constructing a building.
– This covers the manufacture of materials and components, transport and construction.

84% of the CO2 equivalence impact of a building was down in use emissions.

This data is from http://www.bis.gov.uk/assets/biscore/business-sectors/docs/l/10-671-low-carbon-construction-igt-emerging-findings.pdf

That is why policy to date has been biased to making buildings more operationally efficient.

The article then makes the point that raises the importance of embodied (construction) emissions. Namely that since emissions are cumulative, 1 tonne of CO2 equivalence impact occurs for every year this “CO2” is in the atmosphere. So 1 tonne of CO2 at the start of a buildings 60 year life will have twice the impact of 1 tonne emitted during the building’s life.

The longer a tonne of CO2 hangs around in the atmosphere, the more damage it can do.

So it’s potentially dangerous to focus on carbon-intensive solutions that are installed at the point of construction, so that they reduce the operational emissions.

So, it is best to look for principles, materials, solutions etc. that will reduce both the construction (embodied) and operational energy of a building. So, as it’s often said, the general advice is still to optomise the fabric efficiency of a building before other measures.

October 2011 Update

The October 2011 report by the NHBC Foundation (“Housing Research in partnership with BRE Trust”) – Operational and embodied carbon in new build housing – A reappraisal:

Until now, focus has been almost entirely on the carbon emissions resulting from using homes, but clearly the balance between those operational carbon emissions and emissions from producing and installing the materials – the embodied carbon – needs to be considered.

This publication explores a subject which has to date lacked a strong and accessible evidence base. It looks at a range of carbon reduction scenarios as delivered through typical house types and estimates the likely impact both in terms of operational and embodied carbon – providing an insight into the contribution of different technical responses to the low carbon agenda, including the balance between operational and embodied carbon.

Evaluated Scenarios:

Twenty-four scenarios were appraised, using SAP software to determine operational CO2 emissions and BRE Global’s Environmental Profile methodology to analyse embodied CO2eq emissions.

The research considered the following variables:

  • two built forms (detached and mid-terraced)
  • two construction weights (masonry and timber frame)
  • three operational CO2 performance levels (25, 31 and 40% reductions over Part L1A 2010)
  • two dwelling lifespans (60- and 120-year study periods)
  • varying grid electricity CO2 intensity (to account for the expected impacts of grid decarbonisation).

Extracts from the report:

  • The modelling showed a typical percentage split between operational and embodied CO2eq (CO2 equivalent) of 62/38% for masonry construction, and 65/35% for timber-frame construction. These are averaged figures.
  • No significant differences emerged between masonry and timber construction in terms of overall CO2 impact over the 60- and 120-year study periods. The largest difference observed between comparable masonry and timber constructions was 4%.
  • The modelling showed that space and water heating, along with foundations, ground floors, windows/doors and floor coverings, were the largest contributors to overall lifetime CO2 impact. Appliances were also a significant contributor, but building designers have limited opportunity to reduce these emissions via their designs.
  • The typical split between operational and embodied CO2eq in new build housing has been taken as 80% operational, 20% embodied, a position largely confirmed by recent studies[1]. However, within the context of future Building Regulations requirements – which are expected to tighten to the point that new homes will be significantly lower in CO2 from 2016[2] – operational CO2 emissions are set to fall radically. This means that embodied CO2eq emissions will become increasingly significant in terms of the percentage they contribute to the overall CO2 impact of new build dwellings. In addition, typically the more energy efficient a given house type becomes, the greater the quantity of additional materials required to construct it (eg additional insulation, more services). There is also potential that such additional materials (eg renewable generation installations) may have particularly high embodied CO2eq levels. Both these considerations suggest that, as operational CO2 emissions reduce, embodied CO2eq emissions will increase.
  • The replacement of services and other building components has a direct bearing on both operational and embodied CO2eq emissions across the 60- and 120-year study periods.

Assumed lifespan of construction elements:

  • The proportion of embodied CO2eq in masonry construction was found to be higher than that in timber construction. However, this difference was relatively marginal, the maximum difference being 4%. This is because, other than the walls, the majority of building elements were similar in both the masonry and timber constructions modelled.

Which aspects of the dwelling are responsible for the largest CO2 impact?

  • Space and water heating have the largest CO2 impact in dwellings; this remains significant in all scenarios despite diminishing slightly as designs move from 25 to 40% CO2 reduction.
  • Appliances also have a large operational CO2 impact, although dwelling designers have limited ability to help achieve reductions in this area.
  • In both masonry and timber constructions, the impact of foundations and ground floors dominates the embodied CO2eq impact.
  • In masonry construction, the external walls also have a major impact.
  • Because both of these areas will last the lifetime of the dwelling, they should be considered at the design stage when seeking to reduce the overall dwelling CO2 impact.
  • Other elements, such as windows/doors and floor finishes, have a relatively large impact because they are repeatedly replaced throughout the life of the dwelling.
  • The embodied impact of services was found to be approximately 5% of impact at 60 years and 7% at 120 years. However, these results should be treated with caution as some aspects, such as controls, had to be omitted due to lack of available data, and the services were not studied in depth during this project.

Did the varying thermal mass levels have a significant impact on cooling?

  • No clear trend was identified from the modelling carried out, with minimal impact from space cooling in both masonry and timber designs.

UK Solar Hot Water Trial Findings

Posted on by

The Energy Saving Trust did a survery on a large number of UK and Republic of Ireland solar hot water systems.

PDF report on the survey >>

Key Points

  • There were 54 flat-plate systems in the trial.
  • There were 34 evacuated-tube systems in the trial.
    • There was no difference in the annual solar energy yield observed between solar installations using flat-plate solar collectors and those using evacuated-tube solar collectors. This may be because although evacuated-tube collectors have higher insulation, flat-plate solar collectors generally have a larger working area as a proportion of the collector size.
So there are none of the “new” Thermodynamic Panels in the survey. These do appear to be different and better. Providing 24 hour hot water.

Distribution of the surveyed / trial locations:

So for Silver Spray in Cornwall, should get better results as more sunshine:

The solar energy input to the hot water cylinder is at a maximum in summer, with back-up heating providing more energy in the winter months.

It’s key to set the backup (non solar) heating system to run so that the solar heating can be most effective and the house occupants have hot water when desired.

How to improve the performance of a solar water heating system:

  • Using boiler timers and/or solar controllers to ensure that water is only heated by the back-up heating sources after the water has been heated to the maximum extent possible by the sun.
    • Timing of back-up heating and hot water use. Systems
      provided more energy when the back-up heating was
      used just before the main hot water use or at the end of
      the day. This provides a better opportunity for the solar
      collector to heat the water rather than using the back-up.
  • Having an adequately sized dedicated solar volume (that is, a portion that can only be heated by the solar water heating system). Where a dedicated solar volume is not used (for example in systems that do not require the existing cylinder to be changed), the timing of back-up heating has a particularly important impact on performance.
  • Insulation is a vital part of this, as systems with poorly insulated storage cylinders can suffer from inadequate hot water provision in the mornings.

Key Findings:

  • Well installed and properly used systems can provide around 60% of the years hot water.
    • Across the whole trial, the proportion of domestic hot water energy provided by solar power ranged between 9 per cent and 98 per cent (with a median of 39 per cent).
  • Plenty of other findings, see the report.

Customer / Consumer Advice

What to expect from your installer:

  • All MCS installers should be able to provide a detailed breakdown of the specification and costs of their proposed system. They should:
    • Complete a technical survey.
    • Explain how they calculated the size of the system to be appropriate for your hot water usage.
    • Provide an estimate of how much heat will be produced by any proposed system.
    • Supply clear, easy-to-understand and detailed information and advice on how best to use the system and operating instructions.
    • Explain how the system will be installed and if there will be any disruption to your property.
    • Install and set controls and settings to ensure you get the most out of your solar water heating system.
    • Provide clear and easy-to-understand information on product and workmanship warranties.

Ecobuild: An “air tight” building

Posted on by

A principal of modern buildings to achieve thermal efficiency and improved health is to make an “air tight” building .

The aim is to head towards and perhaps meat the Passivhaus standard of air change rate of no more than 0.6 air changes per hour @ 50 Pa. (UK Building Regulation Standard is 10m³/m²/hr @ 50Pa).

Then to control / manage the air, by a mechanical ventilation heat recovery system (MVHR) that exchanges inside air with outside air, BUT heat exchanges the outgoing air with incoming air, so you don’t loose the warmth.

The idea worries people, “I want to sleep with the window open ….”. But reading more and more about this, even sceptics rapidly find the air quality is better in these buildings than those with open windows. And, you can just open the window if you want to ! (eg in summer).

Notes from  the Ecobuild expo talks:

I’ve read elsewhere, that the builders being on-side re the thermal, sealed objectives is key.

 

 

EcoBuild: Thermodynamic Panels (Heat Exchanger)

Posted on by

Thermodynamic Panels

These black panels were on display:

http://www.thermogroupuk.com/thermodynamic.html

These black aluminium panels have refrigerant fluid pumped into them. The heat absorbtion of the black panels changes this to a gas, that is sent to a compressor, which releases heat energy in the heat exchanger where the heat goes into the water. The gas then goes through an expansion valve, putting it back to a liquid before it goes back to the panel. (See explanation & figures below forum comments below).

Claims:

  • 55 degree C water output.
  • Can provide 100% of hot water and heating, 24/7, 365 days a year.
  • Works day or night, as it absorbs heat energy from the atmosphere. It is presumeably helped when it’s sunny !
  • Works when temps are down to -15 degrees C
  • Can be wall installed, which would work well for the Silver Spray proposal.
  • Co-efficient (COP) rating of 4.5 to 7.
  • Distributed by Jewson.
  • 1 panel system (with the boiler and reverse refrigeration bits) is about £4,500.
  • Can have multiple panels in a “toast” stack. Expo figure for that was about £6,500.

Forum Comments:

http://www.greenbuildingforum.co.uk/forum114/comments.php?DiscussionID=7740&page=1#Item_0

  • “Looks like it’s a heat pump with a solar-assisted air to liquid heat exchanger on the outdoors end.” seems to sum it up pretty well !
  • “depending on the heat pump, it’ll be better (better COP) than an ashp in sunlight, but probably worse at night unless there’s much wind to move air across it, although it will have a bigger surface area than in most ASHP’s which will compensate for this to some extent. “
  • “It also has the advantage of not needing (potentially noisy) fans”

Also from the forum, from their N. Ireland distributor:

The system is not new technology; it is basically a freezer “in reverse” and like a freezer consists of a heat collecting panel(s), refrigerant piping and an integrated electric heat pump.  It is a clever application of well tried and tested technology that has been around for almost 100 years.  The panels are made from weather protected anodized aluminium and are not vulnerable to extremes in hot or cold. They are light, weighing only 8 Kg and may be mounted in virtually any orientation or angle.  It has been estimated that 25% of the energy absorbed by a panel comes from solar irradiation, the balance taken from air and rain. Both sides of the panel are available to collect energy. The company that manufactures the system is based in Portugal and to meet growing global demand they have just built a second factory reflecting their 25 year history of success with the product.

You can check them out at http://www.energie.pt/?cult=uk

The Energie system is fully scalable from 1 – 2 panels for domestic hot water, to 4 – 24 panels for central heating right up to 40 panels for large volume hot water requirements. Note that additional panels simply mean faster water heating times, not higher water temperature which is set to between 55 and 60 C maximum.  A typical domestic installation for domestic hot water will have a 250L cylinder with a single panel mounted on the roof.

The heat pump is integrated directly into the Energie cylinder so an existing hot water cylinder cannot be used in this configuration. For central heating and large volume hot water requirements the heat pump (Solar Block in Energie speak) is a stand-alone device. Energie cylinders are either stainless steel or enamelled steel and can come with an additional coil for connecting into a backup heat source if desired. Sizes range from 200L to 6,000L.

All Energie Thermodynamic Systems are accredited under the MCS scheme.

The system uses 407A refrigerant and doesn’t need topping up. The only maintenance may be the occasional replacement of the sacrificial anode in the cylinder should you live in an area with soft water.

Another point raised concerned the panel frosting over in winter. This is possibly best addressed by personal experience.  I installed a 300L single panel system in my home at the start of this year, and although there was some frosting in the very cold weather at that time on the top surface of the panel, the bottom side was clear, and we always had enough hot water. Eight months later we have never had call to revert to either our central heating boiler which has been turned off these past 5 months, or the small integrated immersion that comes with the Energie cylinder. I estimate from measurements I have taken that the Energie system has used an average of 3.6 KWh of electricity per day over the 8 months January to August for our 4-person household at a COP of just over 3.

Hundreds of Energie systems have been installed successfully throughout Ireland over the last 4 years and having come through last winter are well tested for the vagaries of the UK and Irish climate.

Finally some additional information as supplied by Energie can be found using the link below. http://www.e3renewables.com/downloads/

More Information from ThermoGroup

From:

www.thermogroupuk.com/thermogroup_pdfs/Thermodynamic%20Technical%20Information.pdf

1. Aluminium Panels
Refrigerant fluid circulates through the panels and absorbs heat energy from the atmosphere. This increase in temperature changes the fluid into a gas.

2. Compressor
The gas then passes through a compressor and the temperature increases.

3. Hot Water Cylinder
The hot gas then flows through a heat exchanger in the Thermodynamic Block which transfers the heat into the water, which can be used for sanitary hot water, space heating or larger applications such as swimming pools.

4. Expansion Valve
The gas then passes through an expansion valve, reverts back to a liquid and flows back to the panels to
repeat the process.

Figures for Thermodynamic Atmospheric Energy Panels

I read or heard at the show, that increasing the number of panels increases the speed at which the system works. So I think you could add a panel to make the system work faster at grabbing the optimum conditions? (Need to ask them)

Air Source Heat Pump Vs Thermodynamic Atmospheric Energy Panels:

 Air source heat pumps  Thermodynamic
• COP of around 4
• Outputs of 6-18kW
• Outdoor noise pollution
• Requires regular maintenance
• Efficient to just below 0 degrees C
• Fixed sizes
• Fan assisted, low active surface area		 • COP of up to 7
• Outputs of 1.7 – 53 kW
• Silent outside
• Only one moving part
• Works down to -15 degrees C
• Total flexibility
• Active surface area of 3.2m2 per panel
The silent outside bit is pretty key. A lot of air source heat pump users report, things like “you can hardly hear it” and “I don’t even hear it any more, it’s so quite”.

Standard Solar Thermal Panel Vs Thermodynamic Atmospheric Energy Panels:

 Standard Solar Thermal Panel  Thermodynamic
• Provides up to 70% of your hot water
• Must be mounted south facing for best results
• Needs backup from a boiler or immersion heater
• Needs sunlight – low performance in winter/night
• Can only assist central heating
• Fragile glass panels		 • Provides up 100% of your hot water.
• Can be mounted south/west/east/north on a wall
• No backup required – Not connected to boiler
• Works in the dark and down to -15OC – 24/7
• Can provide 100% of your central heating
• Aluminium – tough, long lasting, anti corrosive
They can work on a north facing wall, but work best the more direct solar exposure they get.

Case Studies and Cost

Running Cost:

From www.thermogroupuk.com/thermogroup_pdfs/Thermodynamic%20Case%20Studies.pdf:

  • 4 bed house, one panel & 280 L cylinder, for hot water only = £109.50 pa
  • 3 bed house, 6 panels & thermodyanmic block for central heating only = £346.75 pa

So how much would a central heating and hot water system cost per annum ?
– those figures have an assumed electricity tariff of £0.14/kWh. If the system is part driven by my own solar panels, the cost would be reduced (although you need to factor in the capital cost of the solar panels.)

Purchase Cost:

Need to add in the cost of having it all installed and signed off to the level that’ll hopefully get the Renewable Heat Incentive.

From www.thermogroupuk.com/thermogroup_pdfs/Thermodynamic%20Kit%20Retail%20Prices.pdf

Thermodynamic kits ship pre-gassed, ready for installation and include the following:

  • Thermodynamic Panels/s
  • Panel Fixing Kit
  • Hot Water Cylinder with Thermodynamic Block
  • 30m Copper Pipe
  • 30m Low-loss Lagging

The above thermodynamic kits are suitable for supply of sanitary hot water in domestic applications. Thermodynamic systems for Ambient heating or larger applications require a more detailed specification to ensure we provide you with the right solution.

I’ve emailed them for a rough quote.

EcoBuild: Air Source Heat Pumps

Posted on by

Air Source Heat Pumps

The installers / advisors to projects that were speaking at the lectures for self builders were all very positive about air source heat pumps in terms of how they work and how they stack up from an environmental / energy / sustainable point of view.

There are now automated systems for (for example) an air source heat pump to kick in when Photo Voltaic (PV) panels are producing more electricity than the house is using, and so at those times top up the water thermal store in the building. This can then be used for hot water or heating (under floor works at lower temps) at other times (if needed).

EcoBuild: Waste Water / Drain Water / Shower, Heat Recovery

Posted on by

At Passivhaus levels of energy efficiency hot water accounts for more energy than space heating.

At last weeks Ecobuild, I saw a couple of systems that do this. They capture the heat from hot water that is going down the drain and feed it back into the hot water system. It seems there are 2 systems:

  1. A vertical pipe that the hot water flows down, usually slowed, around the cold water mains supply. Their is heat exchange from the waste water to the cold water, that, in these systems typically, feeds into the water heater / hot water tank.

  2. A system linked to just the shower. So that the heat in the shower waste is immediately put back into the shower. As most showers have a thermostatic valve, this means an instant and guaranteed gain.

+ & – Thoughts

Check the cost of the system Vs the predicted and probable saving for an evaluation of how long the system will take to pay for itself.

  • One of the 2 systems at Ecobuild was the, €299 retail price, system, that you can see at http://zypho.eu/english.html. So price wise, VERY worth considering,  but need to see if:
    • Have to use, what looked like, the integrated shower tray cap / valve bit, or can this work with any shower tray and it’s drainage inlet?
    • Will it cope with sand if used as the post surf outside shower?
    • What is the cost implication of this on each shower Vs a system that copes with multiple showers and other hot water drain pipes (bath, washing machine, dish washer).
    • Does it reduce the cold water pressure? (Does this matter ?)
      I’ve emailed Zypho these questions 
    • Nice write up on the Zypho unit at Ecobuild on the HardHouse blog by Mark.
      – looks good, but questions the heat exchanger and it isn’t yet fully UK approved.
  • Cost Implications:

If used for an external, post surfing, shower, will the system cope with sand, mud, dirt etc?
– it does look like the  Bristol based shower tray system could be put in post a sand trap !
– could even have this bit under the floor in the house and not outside where the cold, frosts etc. could be a problem. It could then also link in to the water outflow from the washing machine, dishwasher and any other ground water outflows of warm / hot water.
–  http://shower-save.com/Joomla_SS/pdfs/Adaptor%20to%2040mm%20for%20RT1-e.pdf
–  http://shower-save.com/pdfs/Recoh-Tray%20grey%20water%20heat%20recovery.pdf

 Per Shower Vertical Pipe
 + Point
  • More efficient as waste water heat put straight back into the shower being taken.
  • Could mean one system to grab the heat from hot water from multiple showers / baths / sinks / washing machines / dish washer etc.
  • Apparently more efficient, as the falling water naturally coats the sides of the pipe (not just the bottom)
 – Point
  • Does this reduce the shower pressure ?
  • Does the system cope fine with shower problems such as hair blocking them up ?
  • You could be sending warmed cold water to an already full heating system. eg You run a bath and by the time you empty the bath the tank has already re-filled itself.
  • Only works for waster water that is on the first floor so that it can flow down the vertical pipe. Seems to have been developed in the US where it can be fitted in the typically occurring basement water inflows.

It seems that if you could get a single whole house heat recovery system that auto feeds the cold water supply to showers, and if they aren’t being used sends the preheated cold water to the water boiler (if it’s not full) would be the best. See the schematic below from http://www.gfxtechnology.com/H-3.pdf

This is also how it’s been set up in the schematic at Bristol (UK) based  http://shower-save.com/
 – also see animation they have at http://content.wavin.com/WAXUK.NSF/pages/Certus-ShowerSave-Animation-EN/$FILE/ShowerSave.swf

UK Water Heat Recovery Supplier Listing:

Test Data for Recoh Units:

From http://shower-save.com/gastec.html

  • Recoh-vert 61.2% efficient, with a mixer shower
  • Recoh-tray is 46.9% efficient, with a mixer shower

Shower-Save is even more efficient with a low flow rate or electric shower:

  • Recoh-vert 64.0% efficient with electric or other low flowrate shower
  • Recoh-tray is 52.6% efficient with electric or other low flowrate shower

Schematics of Waste Water Heat Recovery Systems

Notes from other Websites re these systems:

From http://www.gfxtechnology.com/H-3.pdf:

  • Typically, 80–90 percent of the energy used to heat water in the home goes down the drain. Heat exchangers capture some of the heat in drain-water, allowing it to be reused by incoming water. One type, called a gravity film exchange drain-water heat recovery system, has been found to save 25–30 percent of total water-heating energy needed.
  • This technology is compatible with all types of water heating systems, but it is especially suitable with on-demand water heaters and solar thermal systems. Prices range from $300–400 and paybacks are in the range of 2.5 to 7 years, depending on how often it is used.

From http://www.renewability.com/power_pipe/index.html:

  • Falling film heat exchangers have been around for decades. Other than utilizing the “falling film” effect, however, the Power-Pipe® has little in common with other Drain Water Heat Recovery (DWHR) devices.
  • First generation units suffer from high water pressure loss in the freshwater supply, which causes flow problems. Second generation units resolve the pressure loss issue by adopting a non-counter flow heat exchanger design, which delivers a low heat transfer performance.

Other Water Heat Exchange Systems & Discussions:

From Earth Save Products (bottom of the page) their Heat Squirrel – 120ltr heat recovery vessel (for domestic waste water)

Change Your Behaviour – Bath water heat recovery

One behavioural solution to waste water heat recovery, is to just leave a hot bath, hot sink of water full to cool down and transfer it’s heat to the room(s) before you pull the plug. How often do we pull the plug on a bath of hot water to let that heat head off down the drain, when we could let it cool down (ie heat the interior or the house) first ?