Category Archives: Eco News

Carbon negative bricks !

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Carbon negative bricks showcased prior to market launch

From: http://www.building4change.com/page.jsp?id=1276

Encos uses recovered aggregates and vegetable oil to make sustainable bricks

Encos’ carbon negative bricks and brick slips are set to come to market soon and are on display this week at the Greenbuild Expo 2012 show, which takes place on 9 and 10 May in Manchester.

The bricks and brick slips are made from a combination of recovered aggregates and vegetable-oil-based binders. They are manufactured using a patented method based on research carried out at the department of civil engineering at the University of Leeds by Dr John Forth into the use of alternative binders in construction materials. The process consumes no water, and produces no waste.

Encobricks and Encoslips will be the first Encos products to come onto the market. Prototype products manufactured at the company’s pilot plant have been subjected to comprehensive testing at BRE and have met the standards for fire resistance, freeze-thaw and compressive strength. The products have already been used successfully in the construction of test walls.

Environmental impact

Encos says its bricks use 80 percent less energy to make than clay bricks, and as a result produce only 30 kg CO2e per ton of product. In addition, the plants that produce the vegetable oils used in the Encos binder take in CO2.For every ton of Encos product, 70 kg of CO2 is sequestered within the binder.

But looking at their site, these aren’t yet in commercial production 🙁

“A scale production plant is now fully designed with production planned for mid 2013.”
– http://encosltd.com/products/production/

Cement production CO2 to fuel !

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Pond Biofuels Takes CO2 From Cement Kiln, Grows Algae And Turns It Into Biofuel, that then feeds the cement Kiln’s 🙂

http://www.treehugger.com/renewable-energy/pond-biofuels-takes-co2-cement-kiln-grows-algae-and-turns-it-biofuel.html?campaign=daily_nl

To make cement, you cook calcium carbonate at high temperature, producing 4% of the world’s carbon dioxide in two ways: through the fuel used to heat the kiln, and through the chemistry of converting calcium carbonate to lime and carbon dioxide.

But as climate skeptics are so fond of telling us, plants love CO2. So Pond Biofuels set up shop next to St. Mary’s Cement and feeds gases from its stack to algae taken from the nearby Thames River. The algae grows in its algae condos, sucking up sulphur and CO2 and emitting oxygen.

The algae is then harvested, dewatered and processed. It can be turned into100 litres of biofuel per tonne of algae, or as is being done at St. Mary’s right now, fed back into the cement plant to replace coal or coke.

UK Solar Hot Water Trial Findings

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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: Thermodynamic Panels (Heat Exchanger)

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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: Solar Panel Angles

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There may be a problem with the current Silver Spray plans and the angles for the solar panels. The current plan is for the panels to be bolted onto the proposed flat roof at the back.

  • Solar panels should be south facing and between 20 and 60 degrees.
    • I’ve heard / read that the ideal angle for solar panels in Cornwall is for them to be at 30 degrees (and south facing).
    • Below 20 degrees panels don’t self-clean when it rains. Dirty panels are less efficient
    • The angle that solar panels are normally mounted on flat roofs is usually low to reduce the amout they can get grabbed by the wind and ripped off the roof !
    • It could just be that a framework for the panels is factored into the building so that there is no chance it can be ripped off by the wind.
    • Flat roof mounting systems for panels all seem to be at about 10 degrees, so that the gap between panels is around 38 cm, and so that their is reduced possible “wind load”
    • Current rear flat roof area is about 4.1 x 8m = approx 32.8 sq m. If panels are all flat, a 4kW system takes about 28 sq m. So will need to see how the space works out.
    • See http://www.bauder.co.uk/photovoltaics-and-rooflights/photovoltaic-energy/baudersolar/pv-modules – images below – gap between panels moves up to 1.36m from 0.38m as solar panel angle of tilt changes from 10 to 30 degrees. But see reasons below for wanting 20 degrees or more tilt.
    • The Energy Saving Trust matrix for PV angle of tilt and how much south facing, that suggests optimum is south facing and between 20 and 30 degrees tilt.

  • More vertical panels do better in the winter, when the sun is lower in the sky. You are more likley to want more hot water in the winter (for space heating) and more electricity generation (to power feed the air source heat pump). BUT only 10% of generation output will be in the winter, so best to angle the panels for max, over the year, output.

I ran figures through the Energy Saving Trust calculator for a few variations at the Silver Spray postcode location:

  • South slope, XLarge 4Kw, 90 degrees = 2,688 kWh pa
  • South slope, XLarge 4Kw, 60 degrees = 3,499 kWh pa
  • South slope, XLarge 4Kw, 50 degrees = 3,643 kWh pa
  • South slope, XLarge 4Kw, 40 degrees = 3,716 kWh pa
  • South slope, XLarge 4Kw, 30 degrees = 3,715 kWh pa
  • South slope, XLarge 4Kw, 20 degrees = 3,640 kWh pa
  • South slope, XLarge 4Kw, 10 degrees = 3,492 kWh pa
  • South slope, XLarge 4Kw, 0 degrees = 3,274 kWh pa

EcoBuild: Photovoltaic, PVT Vs PV or PT

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Photovoltaic Thermal:: EcoBuild Expo Update

At the Ecobuild expo, there were a LOT of companies who had photovoltaic elec or water heating systems.  Few were combined PVT (both electricity and heating water). So I started asking why. Speaking to those that make the panesl and installers / advisors the consistent reply was that the reduction in output of both systems was more than 50% down on what you’d get if each was stand alone. One company that produced PV and PT panels said that:

  • A PV panel could produce around 280 Watts  of elec, a PVT panel about 120 Watts
  • A PT panel over 200 (I think degrees) water, but only 40 degrees from PVT.

Yes, it’s still good to cool down PV panels, with ventilation, or even surrounding green roofing. But it seems that cooling them, by linking in pipes to generate hot water doesn’t work. It seems that the temp hot water panels work at is so high to be efficient, that takes out too much electricity production. Or you compromise the amount of hot water production by having the panels at a much lower temp. ie to be efficient they both operate at vastly different temperatures.

So that means looking at seperate systems for electricity production (PV), hot water productin (PT) and something for when the sun isn’t shining for hot water (for taps and heating).

 

EcoBuild: Air Source Heat Pumps

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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).

Life cycle of window materials – energy consumption and environmental impacts

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A great report by the School of Engineering at Napier University in Edinburgh on windows:

Frames of different materials have been assessed on the basis of their production, energy consumption and environmental impacts.

The investigation shows that aluminium and PVC frames exhibit large amounts of
environmental burdens. Accelerated ageing tests have been carried out to test the
durability of windows against weathering impacts. These tests show that aluminium clad timber windows are comparatively least affected by environmental impacts.

CONCLUSIONS (from the article)

  • Aluminium frames cause the highest burden to the environment because of the dangerous pollutants release and high energy consumption during aluminium production. PVC contributes large amounts of poisonous pollutants throughout its life cycle, while timber window frames have the least environmental burdens.
  • Embodied energy analysis has been carried out for a standard 1.2m × 1.2m window. Aluminium windows have the highest embodied energy, amounting to 6GJ. PVC, Al-clad timber and timber windows have embodied energy of 2980MJ, 1460MJ and 995MJ respectively.
  • All frame materials deteriorate to various degrees by environmental impacts. PVC is sensitive towards heat and UV radiation. Timber if not frequently treated, can easily be affected by environment. Aluminium, if not protected well by coatings, gets damaged under corrosive conditions especially in coastal and industrial areas. Al-clad frames are unlikely to deteriorate due to their protective coatings and appear to be the best choice from this point of view.
  • A survey analysis shows that aluminium and timber windows can easily last more than 40 years. Al-clad timber being new on the market, is expected to have a service life well over 40 years. PVC windows, in most cases, are reported to have an optimum service life of 25 years.

Winter Driving Rain May Increase

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OK, we know that man made climate change is here, but don’t know how much the systems will tip it to being worse or to self regulate (or stay on the current trajectory).

But it does mean, that on top of it being a very exposed site, there is the potential for driving rain to increase. See the map below, taken from www.innovateuk.org (PDF).

Talking to surrounding residents, that also look out over Perranporth beach, they all say the site gets a full weather beating on a regular basis. The www.innovateuk.org (PDF) recommends the following detailing, that I’m sure ra-studio are already on top of:

  • recessed window and door reveals
  • projecting cills with drips
  • render finishes
  • extended eaves
  • greater laps and fixings to roof and cladding fixings
  • avoidance of fully filled cavities.
There is also (apparently) the issue that materials may behave differently. Again, I’ll leave that to Robert at ra-studio.

Average 57% of energy on space heating !!!

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According to the Feb 2012 edition of “House & Garden”:

The average British household uses a whopping 57 percent of it’s energy consumption on space-heating, and a further 24 percent on water-heating ….

I hope / suspect this figure is coming down as the “low hanging fruit” of people putting better insulation in existing housing stock and better insulation and seals etc. into new housing stock.