Category Archives: Buildings
I wrote Green-Living because this IS in many ways a ‘living house – run by green-power.
Hamburg Now Has an Algae-Powered Building
Last spring, Arup, the design and engineering firm that brought the world the Centre Pompidou and the Sydney Opera House, unveiled their latest hypermodern architectural creation in Hamburg. From the outside, the surface of the 15-unit apartment building just looks like a bubbling green lava lamp stretched over an entire building. But those moving bubbles serve a function: they help to feed and order the living algae embedded within the Bio Intelligent Quotient (BIQ) building’s exterior skin. In turn, the 8-foot by 2-foot glass panels of green scuzz—the building’s $6.58 million bioreactor façade—power the entire structure, making it the world’s first algae-powered and theoretically fully self-sufficient building ever.
Conceived in 2009 as part of Hamburg’s International Building Exhibition, Arup’s BIQ building is part of a European movement to design carbon neutral, self-sustaining, and renewably powered structures. (Germany, for example, is pushing to achieve 35 percent national energy reliance on renewables by 2020.) Alongside a series of houses demonstrating solid timber carbon-locking constructions and greywater recycling systems, the BIQ was funded in large part by the German government as a means to incentivize the development of new adaptive,smart construction materials. Of all the technologies on display, though, algae power has perhaps the finest pedigree and greatest potential.
Research on the energy potential of algae, once just considered a slimy pond nuisance, began in earnest during the gas crisis of the 1970s at America’s National Renewable Energy Laboratory. Producing about five times as much biomass per square foot as soil grown plants, and thriving on carbon dioxide, algae have the potential to grow almost limitlessly and produce oily lipids and gases that can be transformed into relatively clean energy. But official research largely ended in the 1990s as scientists concluded that the benefits of feeding, fostering, and harvesting algae were not yet competitive with then-low oil prices. Still, many independent research groups kept the dream of algae power alive over the next couple of decades, slowly improving the efficiency and cost effectiveness of proposed systems. From 2009 onwards, at least a few plans for algae bioreactors have floated around the design community and academic circles, although few very have become reality.
The BIQ is the first residential structure to fully realize the dreams of algae power advocates. The building is coated on its two sun-facing sides with glass-plated tanks of suspended algae. Pressurized air is pumped into the system, feeding the organisms carbon dioxide and nutrients while moving them about—creating the lava lamp effect—to keep them from settling on the glass and rotting. Scrubbers clean off any sticking biomass, freeing up more sunlight for the remaining algae to perform photosynthesis. Periodically, algae are culled, mashed into biofuel, and burned in a local generator to produce power. Excess can be sold off for food supplements, methane generation to external power providers, or stored for future use. The result is a building shaded from summer heat by algae foliage, insulated from street noise, and potentially self-generating the power to sustain its own harvesters, heat, and electricity.
Critics of the design and of algae power in general argue that transforming algae into biofuel requires energy, as does manufacturing and pumping in nutrients. They also take issue with the fact that the BIQ is not totally self-sufficient and that algae technology is more expensive than solar power. They claim that these points make the technology more of a novelty than a useful solution—or at least that its potential has been over hyped.
Even Arup will concede to most of these points, admitting that the BIQ has only achieved 50 percent energy independence thus far. However they believe that total independence is within reach, especially by integrating solar into the design. The costs—$2,500 per square meter for the bioreactor system alone—are astronomical, but the developers hope that as the technology evolves, prices will decrease, while the savings of fuel reduction will offset the remaining extra costs. They hope that soon high-energy consuming businesses like data centers will help pilot their tech in the search for grid independence, and that algae power can take off in residential homes within a decade.
The Arup team is made up of futurists. The same year that they unveiled the BIQ, they released the “It’s Alive” report, envisioning a 2050 with mega-skyscraper vertical farms, jet-powered maintenance robots, and photovoltaic paint, a classic wish list of quasi sci-fi tech. So it’s probably reasonable to question how realistic their optimism about algae power is. But they’re no longer the lone nuts on the road to mass algae power. Grow Energy of San Diego, founded in 2012, has produced two home algae bioreactors and hopes to be able to manufacture, deliver, and install its first systems—generating 35 percent of the average home’s energy with minimal maintenance—for $12,000 per system starting next year.
Although all of this means we’re likely to see a greater number of more efficient buildings like the BIQ in the next few years, we’re still many years off from an algae generator in every home. But given last month’s pledge by the International Union of Architects to end carbon emissions from buildings by 2050, and similar global initiatives in search of carbon-neutral, self-sufficient structures, the emerging tech is likely to find more champions.
It’s hard not to look at the BIQ, in spite of all its flaws, and see a system that fits the order of the day in every way: a carbon locking, self-sustaining, off the grid, neutral power system. If the only hitch is that, in early stages of development, it’s still a bit pricey and buggy, that’s hardly a death knell for an otherwise optimistic and inspiring tech.
The reason we will put a pellet stove in our new home and not a traditional stove that burns wood, is simple. It’s easier to use. We are fed up stoking the fire and cleaning the ashes from the grate – AND ashes from everwhere else in the room.
Most of that comes from the simple automation that is built into the stove. Plus unlike a standard wood stove, a pellet stove allows one to set the temperature necessary to maintain comfort using a standard thermostat.
Using the stove means we use 1/2 tank LPG in 18 months.
There’s a company called Nest that has built a smart thermostat. What makes it interesting is that it learns from how you use it. Over time, it anticipates your needs (like turning down the temperature at 10 pm every night) and does it automatically.
Further, since it is Internet aware and wireless, you can control if from anywhere (i.e. from your smart phone).
Now, although this tech looks pretty simple, I suspect this device and others like it are the start of a big market for home automation. Essentially, smart systems connected to sensors around your home that makes running a home at peak efficiency, easier than ever.
Nest, with it’s ergonomic/simple approach to design, is certainly going to try to become a leader in this market.
Improving the Insulation on Older/Poorly-Built Buildings.
AKA Raising the B.E.R. on (older) buildings.
The B.E.R. Rating. Building Energy Regulations of a building means to improve it’s insulation and ultimately to lower its eco-footprint and cost in terms of fuel-consumption. It’s a frightening thought that buildings bought before the UK building boom of the ‘80’s (Ireland of the late 90’s) now cost more to heat per year than the initial cost of the building itself. Fuel prices have risen at 1.5 times the rate of inflation over the last 30 years.
It is generally accepted (B.E.R. standards, LEED (US), SAEI- Ireland, Department of Energy and Climate Change (DECC); UK) that 35% of heat is lost from a building via poorly insulated walls.
The overall heat loss from a building can be calculated as
H = Ht + Hv + Hi where H = overall heat loss
Ht = heat loss due to transmission through walls, windows, doors, floors and more
Hv = heat loss caused by ventilation
Hi = heat loss caused by infiltration (W).
Heat-loss in buildings (or heat0gain in warm lands demands the value of the building every generation or less nowadays. (Protek-usa. Heat-Gain-Loss-Buildings.pdf). this pdf starts with a very good definition of heat loss via radiation, conduction and convection.
N.B. Sand-cement render on the exterior of a building (especially if insulating the interior) will result in the building ‘sweating’ and possibly developing Merulius lacrimans – dry rot – or -Serpula lacrimans – ‘Real-Dry-Rot’). Both will destroy a building and even its neighbours. If a house is to be ‘sealed’ great care must be taken that it remains “breathable”.
There are two (generally) accepted ways of insulating a building (insulating the envelope);
External; “Bubble-wrapping” the exterior – e.g. polystyrene slabs fixed to the exterior walls (using plastic ‘mushroom’ plugs) and plastering with a patent-polybond-skim over a mesh that holds all in place. This technique ‘defaces’ the exteriors and ‘technically’ needs planning permission.
Internal; fitting patent pre-insulated slabbing to interior walls (ceilings too if possible) to retain the heat generated within the building. Fixed as above or with laths between wall and slab this system is usually seen as the best as it retains heat before it hits the exterior wall and is absorbed (before being lost if there’s no external insulation). This system is often eschewed as it reduces the volume of the room (room-size) considerably in small homes/offices. It is seen as the most desirous in larger buildings as the heat is retained and in fact rather like any light-weight structure (boat-caravan) is easily heated very quickly.
In both cases however the incidence of leakage (drafts) and of course doors, window, and especially glazing must be considered. Poor glazing techniques (ie single-glazing or poorly designed/compromised/faulty) can cost 23% heat loss normally but even far more if the rest of the structure is well insulated.
From seai.ie/(Power_of_One) ; “Internal insulation systems involve using insulated dry-lining boards. These boards comprise of 12.5mm of plasterboard with insulation bonded to the back with a vapour barrier between the two. The insulation ranges in thickness from about 25mm to approximately 60mm though this depends on the make and availability. A lot of these boards would have similar levels of thermal conductivity because the main types of materials that are used, i.e. polyurethane and polyisocyanurate, have very similar thermal properties. However, it has the disadvantage of placing the thermal mass of the wall outside your heating envelope. External insulation is another option, which would have the added advantage of keeping the thermal mass of the concrete walls within your envelope. It is very popular method in Europe, and is becoming more common in Ireland. With external insulation, the insulation panels are applied to the walls, then a protective mesh that protects the insulation against impact damage is applied, then a basecoat and usually two coats of render”.
Floors are often disregarded as it’s generally thought that heat rises – which is true. But as temperature rises within a structure the heat will always seek to find a way out; even downwards. Floor insulation must reflect what is planned above. 15% heat loss is the accepted figure but again as the better insulation of the upper areas improves the rate of loss through the floor will increase.
A gap of just 1/8 of an inch under a 36-inch door lets in as much air as having a 2.4 inch wide hole in the wall. Since people often adjust the thermostat and leave heat running longer when they feel a draft, preventing air infiltration can greatly reduce energy usage. See ‘Notes’ below.
Air-pressure-tests and infra-red video cameras
will show leaks and vents as well as ‘cool-spots’ in covered areas that are lacking insulation.
Detailed business information on Air Pressure Testing Companies located in the UK, including photos, contact details and customer reviews. freeindex.co.uk/air_pressure_testing/
Heat-Exchange Systems. aka Heat Recovery System.
No discussion on heating/cooling any building can Not but consider ‘heat-exchange-system’ see; Heat-Exchange Systems.
‘Geo-thermal’ means absorbing some of the latent heat from the earth (or running water/large body of water) and enhancing the heat by passing it through a heat-exchanger – the inverse of a milk pasteurising system. It’s usually used for underfloor systems (at about 33ºC) though new radiators are coming on the market to work with low-heat-radiators.
I opened a website on heating on old home and one thing jumped out at me – I hadn’t mentioned the last time – THE most obvious and the FIRST thing ones does – AUDIT. If it ain’t measured it won’t count (or get done).
- Search for articles on old house websites such as the Old House Journal
- Reference books such as Greening Steam: How to Bring 19th Century Heating Systems in the 21st Century (and save lots of green!) by Dan Holohan
- Ask a question online at www.heatinghelp.com
Passive-Solar Heating. (aka the No-Brainer).
What is a Passive House? It is a building in which a comfortable interior climate can be maintained without active heating and cooling systems. The house heats and cools itself, hence “passive”. By good design and an average 10% ‘extra-spend’ in design and building will eventually save many 10’s of thousands of Euro or Pounds in fossil-fuel heating-bills (and airconditioning). See; http://passiv.de/en/
However as we are discussing older buildings we must assume that other than physically turning a building on its axis to avail of ‘solar-gain’ and to build (sympathetically) around it possibly with a forest to cut-down on chill-factor to NW, N, NE. We must concentrate on apertures, walls, roof and flooring. Further measures – keeping the heating-bills down by reducing the temperature by a degree or two can be found in this pdf; london.anglican.org/Church-heating.pdf
A book issued hand-in-hand with the Anglican Church offers help; Creed and Creation: A simple guidebook for running a greener church. 2007.
Flooring: When insulating the floor is it possible to add underfloor heating? Underfloor heating uses water heated to 33ºC as opposed to ‘normal’ heating (radiators) which runs at 65ºC.
Notes on insulation and ‘off-grid’ homes;
Australia; A push has been made to help homeowners in providing their own power. Renewableenergyworld.com/push-for-homes-to-be-powerhouses
In France A push has been made to tax energy wasters and feed that money towards homeowners insulating and providing their own power.; Renewableenergyworld.com/france-taxing-carbon-emitters-in-an-effort-to-overhaul-consumer-energy-costs
A newly constructed apartment complex in Newport News, Va., proves that that future may already be on the way. The Radius Urban Apartment complex windows fabricated with Solarban 70XL glass and SunClean self-cleaning glass by PPG Industries. That’s right, windows that will shrink your energy bill and clean themselves. And they’re both Cradle-to-Cradle certified.
According to the company, Solarban glass is a transparent solar-control, low-emissivity glass that lets light through while also acting as thermal insulation. By transmitting high levels of daylight while blocking the sun’s heat energy, windows made with Solarban 70XL glass can reduce summer cooling costs by as much as 25 percent. PPG also claims that Solarban 70XL glass can cut furnace heat loss through windows in half, which can lower heating bills significantly in the winter months.
And now for the best part: SunClean glass is formulated with a proprietary coating that becomes “photocatalytic” and “hydrophilic” after prolonged exposure to sunlight. Photocatalysis enables the coating to gradually break down organic materials that land on its surface, while hydrophilicity causes water to sheet when it strikes the coating so that decomposed materials are naturally rinsed away when it rains. Earthtechling.com/self-cleaning-solar-glass-is-a-lazy-mans-dream/
Creed ; Creed and Creation: A simple guidebook for running a greener church, Gillian
Straine & Nathan Oxley, Aldgate Press, 2007
Department of Energy and Climate Change (DECC); https://www.gov.uk/government/organisations/department-of-energy-climate-change Accessed 25/01/2013
National Archives; http://webarchive.nationalarchives.gov.uk/+/http://www.berr.gov.uk/energy/statistics/index.html Accessed 25/01/2013.
RESATS; https://restats.decc.gov.uk/cms/welcome-to-the-restats-web-site/ Accessed 26/01/2013
Telegraph – radiators; http://www.telegraph.co.uk/property/propertyadvice/jeffhowell/8214378/Home-improvements-how-to-heat-the-house-this-winter.html Accessed 27/01/2013.
Links and Resources;
Dublin Heritage-Conservation Dublincity.ie/Planning/HeritageConservation/Conservation/pdf
Heat loss for engineers; http://www.engineeringtoolbox.com/heat-loss-buildings-d_113.html
How to get free cavity wall and loft insulation; It’s not too late to get free insulation installed in your home. And if you’re on a low income or benefits, you could get cash or vouchers as well. http://uk.finance.yahoo.com/news/free-cavity-wall-loft-insulation-160620453.html
Don’t qualify? You can still save on insulation: If you don’t qualify for free insulation for whatever reason, you can still get discounted installation with all of the major energy companies, and others such as Sainsbury’s Energy.
A detailed guide to insulating your home. ExternalWall Insulation Systems (EWIS) can be used on new or existing buildings; http://www.youngdesignbuild.ie/EWIS.html
Sempatap Thermal Solid Wall Insulation Materials & Tools; http://www.youtube.com/watch?v=gKXb9fx9cmw
Passive House (Passivehaus); For passive construction, prerequisite to this capability is an annual heating requirement that is less than 15 kWh/(m²a) not to be attained at the cost of an increase in use of energy for other purposes (e.g., electricity). Furthermore, the combined primary energy consumption of living area of a European passive house may not exceed 120 kWh/(m²a) for heat, hot water and household electricity. The combined primary energy consumption of living area of a standard house is approximately 220 kWh/(m²a) for heat, hot water and household electricity. External Links for more information: http://www.passiv.de and www.europeanpassivehouses.org More info on ‘passivehaus’; The main design features of passive homes include: –
- Positioning of homes and buildings to avail of free solar energy. Orientation and selection of the correct site for your home is imperative. Proximity to and height of adjoining buildings can reduce your solar gain.
- Higher levels of insulation help reduce the cost of heating.
- Air tightness of your home is crucial in keeping all that free solar energy within the home.
- Locating the majority of your windows on south facing elevations and reducing the size of any north facing windows.
- As your home is now extremely air tight, mechanical ventilation will need to be introduced. By ensuring that this ventilation has heat recovery the incoming fresh air shall be preheated by the extracted air. This simple measure helps keep your home warm without having to reheat the fresh air.
- Correct detailing of junctions between the external fabric and windows and doors to reduce heat loss.
- Introducing solar panels will help produce approx. 70% of your required hot water once sized correctly and positioned to face south to optimise the solar gain.
- Other simple measures such as using A rated kitchen appliances and fitting low energy light bulbs will help ensure your new home is both comfortable and warm to live in.
Ireland; Better Energy Homes Scheme; see:- Citizensinformation.ie
UK; Solid wall insulation – Energy Saving Trust .www.energysavingtrust.org.uk
Solid Wall Insulation Grants, Home Insulation Grants; www.governmentgrantssolidwallinsulation.co.uk
Cavity wall insulation – Homes – Energy Saving Trust; www.energysavingtrust.org.uk
Air-pressure Testing; http://www.freeindex.co.uk/categories/industry/industrial_services/air_pressure_testing/
Make sure that there are no unnecessary obstructions in front of radiators, heaters and air ducts. · Bleed and clean your radiators on a regular basis to ensure water circulates properly. Clean off the fluff and dust from the grill and filters of convector radiators and heaters. Install thermostatic radiator valves (TRVs) to prevent spaces from becoming overheated.
A gap of just 1/8 of an inch under a 36-inch door lets in as much air as having a 2.4 inch wide hole in the wall. Since people often adjust the thermostat and leave heat running longer when they feel a draft, preventing air infiltration can greatly reduce energy usage. Sealing up those cracks will make you feel comfortable and keep more money in your pocket. Remember for every cubic foot of heated or cooled air (that you have paid to condition) that leaves your house, one cubic foot of outside air enters!
Looking for just one thing you can do to improve your home’s energy efficiency? Significantly reduce air infiltration. Gaps or cracks in a building’s exterior envelope of foundation, walls, roof, doors, windows, and especially “holes” in the attic floor can contribute to energy costs by allowing conditioned air to leak outside.
Most Common Sources of Air Infiltration:
- Bypasses (attic access door, recessed lighting, plumbing stacks, dropped soffits, open frame construction, duct penetrations, electrical penetrations, etc.) in the attic floor regardless of the presence of insulation, which by itself is not an air barrier. If you see dirty insulation, air is getting through.
- Between foundation and rim joist
- Crawl spaces
- Around the attic hatch
- Between the chimney and drywall
- Chimney flue
- Electrical and gas service entrances
- Cable TV and phone line service entrances
- Window AC units
- Mail chutes
- Electric outlets
- Outdoor water faucets entrances
- Where dryer vents pass through walls
- Under the garage door
- Around door and window frames
- Cracks in bricks, siding, stucco and the foundation
- Mudrooms or breezeways adjacent to garages
How radiators work; Telegraph (UK);
As the water flows through the radiators it gives up its heat to the rooms, thus returning to the boiler at a lower temperature. Designed by the Prussian-born Russian; Franz San Galli
A Low temperature heating system requires a larger surface area to provide enough heat energy. Radiators need to be up to 100% bigger to compensate for the lower temperatures. In other words it contains more mass and area.
London Care of Churches Team
The Engineering Toolbox; provides;
1. Heat loss through walls, windows, doors, ceilings, floors, etc.>
The heat loss, or norm-heating load, through walls, windows, doors, ceilings, floors etc. can be calculated as
Ht = A U (ti – to) (2)
Where; Ht = transmission heat loss
A = area of exposed surface (m2)
U = overall heat transmission coefficient (W/m2K)
ti = inside air temperature (oC)
to= outside air temperature (oC)
Heat loss through roofs should be added 15% extra because of radiation to space. (2) can be modified to:
H = 1.15 A U (ti – to) (2b)
For walls and floors against earth (2) should be modified with the earth temperature:
H = A U (ti – te) (2c)
Where; te= earth temperature (oC)
Overall Heat Transmission Coefficient
The overall of heat transmission coefficient – U – can be calculated as
U = 1 / (1 / fi + x1 / k1 + x2 / k2+ x3 / k3 +..+ 1 / fo) (3)
Where; fi = surface conductance for inside wall (W/m2K)
x = thickness of material (m)
k = thermal conductivity material (W/mK)
fo= surface conductance for outside wall (W/m2K)
The conductance of a building element can be expressed as:
C = k / x (4)
Where; C = conductance, heat flow through unit area in unit time (W/m2K)
The thermal resistivity of the building element can be expressed as:
R = x / k = 1 / C (5)
Where; R = thermal resistivity (m2K/W)
Using (4) and (5), (3) may be modified to
1 / U = Ri + R1 + R2 + R3 + .. + Ro (6)
For walls and floors against earth (6) should be modified to
1 / U = Re + SR (6b)
2. Heat loss by ventilation
The heat loss due to ventilation without heat recovery can be expressed as:
Hv = cp ρ qv (ti – to) (7)
Where; Hv = ventilation heat loss
cp = specific heat capacity of air (J/kg K)
ρ = density of air (kg/m3)
qv = air volume flow (m3/s)
ti = inside air temperature (oC)
to = outside air temperature (oC)
The heat loss due to ventilation with heat recovery can be expressed as:
Hv = (1 – β/100) cp ρ qv (ti – to) (7)
Where; β = heat recovery efficiency (%)
An heat recovery efficiency of approximately 50% is common for a normal cross flow heat exchanger. For a rotating heat exchanger the efficiency may exceed 80%.
This is a series of interesting blogs by John Robb. I can claim no credit other than to acknowledge posting them for educational purposes- only. I find that some of these are brilliant, and some … less so and I can only gather and collate.
Some have inspired me further and some have left me wondering if there’s hope for the human race – however not all of us are experienced and we all need an ‘in’ – somewhere to get started. Dear reader I leave that to you. I post this to hope to motivate you and perhaps you too will get the RSS directly and join in Robs – Resilient Community.
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What I Found Interesting This Week 1/19/2013
By John Robb
What makes a home valuable in the 21st Century?
Increasingly, it’s whether the home or the community it is in produces food, energy, and water in abundance.
A home or community that does that well, is a gem. A place and a way of life that will be sought after. So, on that note, here’s some ideas I found this week on how to add this capability to your home and community today.
If you are like me, you love to own a greenhouse (or an green-atrium). For me it’s both the productivity it provides and the aesthetics it adds to a home. When I think about a greenhouse, I typically think of something akin to thissuburban life support system.
Note how the greenhouse is almost as large as the home itself — given that, I’ll give them a pass on the wasted yard space!
However, a greenhouse that big may not be something you can justify yet. Over time, that will change as growing organic, healthier, high quality food at home and locally becomes easier and more desirable/necessary to do. In the meantime, you might want to look at smaller, stand alone structures.
If you want to go fully DIY, using recycled materials, here’s aschool project that used plastic bottles that may motivate you:
For those into Buckminster Fuller’s geodesic domes, here’s a simple kit called Starplate (you can purchase it here), that you can use for both a greenhouse and a chicken coop. It’s basically a set of metal connectors, you buy standard wood (i.e. 2×4), cut it, and assemble it.
Here’s also a Geodesic dome kit and software tool for designing and building light weight domes yourself. It was funded on Kickstarter in 2011 and it delivered ($99 for the kit). Note that this kit uses dowels and flexible plastic connectors. So, if you add a covering, it’s probably best to use it for “shading” plants with cheese cloth during extreme heat. If you do, watch out for the wind.
Speaking of wind or heat… If you live in a place that features both, you may want to build a submerged greenhouse. Here’s an example of one from project FLORA. It uses the ground as a heat sink (a place that stores extra heat when you have too much or a source of heat when you have too little) and as a shelter against the wind. This design will help the greenhouse maintain even temps and it will minimize damage to the structure.
If you like the idea of a convertible greenhouse — one that you can open and close with minimal effort — here’s an amazing design from a company in Montana. Unfortunately, the systems are a little pricey and I haven’t found a good DIY design.
If you are really ambitious. Here’s a self-contained greenhouse called the “Integrated Food and Energy System” that’s being prototyped right. It combines solar panels (for energy and shade) and aquaponics to produce lots of food in harsh climates (from urban jungle to desert) with minimal inputs.
Remember, adding a greenhouse is a good way to improve the productivity of your home. However, don’t over-invest in a greenhouse if you haven’t established a gardening routine yet. I also suspect a greenhouse + some help from a localfoodscaper (a local farmer or master gardener that delivers organic and micro-farming expertise to subscribers for a fee) would be an extremely effective combo.
Hope this helps get your head around the possibilities. Keep adding value to your home and your community. The future is what you make of it.
It will probably surprise many people to find out that there are different generations of Solar Vacuum Hot Water Systems and ALL are still being sold today. You may have just bought one but which generation is it ?
This is why you see HUGE differences between performance of solar vacuum systems and why there is so much confusion. We have many requests from people who have just bought Solar Vacuum systems and they can’t understand how our customers systems are producing so much more energy than them.
THIS POST WILL EXPLAIN THE MAIN DIFFERENCES…
NOTE: This is the first time you have probably heard anything about the different generations of Solar Vacuum Technology anywhere.
FIRST Generation Solar Vacuum Systems, (about 35 years old), still being sold on the market, always compared to flat plates due to their low performance.
How to recognise one ?, simple, it has a single wall (not double skinned vacuum) clear glass tube and a strip of absorber inside.
Fig: First Generation Solar Vacuum System – (approx 35 years old)
Whilst they are still available to buy in very well known BRAND NAMES, they are quite old at this stage. How did they come about. Simple, a bright Engineer about 35 years ago looked at flat plates in sunny climates and made an assumption that if he put the strips of a flat plate absorber into glass tubes, he would improve on the output of flat plate collectors in cloudy climates. Here is a picture of a flat plate solar collector with its covers off.
He simply decided to split the absorber and put it in glass tubes. A new version of this has a direct flow pipe instead of a heat-pipe. THIS IS FIRST GENERATION SOLAR VACUUM HOT WATER TECHNOLOGY.
SECOND Generation Solar Vacuum System’s, (about 25 years old), still being sold on the market, noted for their lack of performance in poor weather and over-heating problems in sunshine. THIS IS THE MAJORITY OF SOLAR VACUUM SYSTEMS BEING SOLD ON THE MARKET TODAY AS THE COLLECTORS CAN BE SHIPPED BROKEN UP IN LONG BOXES.
You will always hear about sizing to only do 90% of your hot water in case of overheating (of course this makes it poor performing in winter), the adding of dump radiators, etc. with this technology. Here is a picture of this type of solar heat-pipe. There is a condensing heat-pipe running into a twin walled vacuum tube with a sealing cap to hold in the heat. The tube always carries a selective coating so it looks black on the outside. The heat pipe then plugs into the manifold and heats up the manifold. When the manifold gets heated, it transfers the heat to the water passing through. This process is fairly inefficient.
Fig: Second Generation Solar Vacuum System – (approx 25 years old)
THIS IS SECOND GENERATION SOLAR VACUUM HOT WATER TECHNOLOGY.
THIRD Generation Solar Vacuum Systems, (about 8 years old), still being sold on the market BUT only a few suppliers make this generation of system, it is noted for more stable performance than Heat Pipes and has reduced the overheating issues on really hot days. It is more expensive to produce and unless it is shipped in one piece, it has to have rubber seals and run at low pressure. THIS IS TYPICALLY CALLED A U-TUBE OR DIRECT FLOW COLLECTOR.
Here is what it looks like:
You can see that the circulating water runs into the glass tube via copper pipes unlike any of the 1st and 2nd generations where the water only runs in the manifold. The tubes are twin walled and have a selective coating and appear black on the outside.
ONE MAJOR DRAWBACK (and it is a biggie): If this type of collector comes as a kit (and not in one piece out of the box) and has to be assembled at the installation site, then it will cost a significant amount of money to change a tube. The system will need to be drained down, tube changed and then refilled, this is in effect a FULL SERVICE every time you want to change a tube. Typically the new tube will come with all the pipework so can be over £120 a tube ON TOP of the full service cost.
If the collector is one piece and can’t be broken down, then this does not apply, the changing of a glass tube takes seconds, like changing a light bulb and is a few quid at most. THIS IS THIRD GENERATION SOLAR VACUUM HOT WATER TECHNOLOGY.
FOURTH Generation Solar Vacuum Sytems, (about 4 years old), this is proprietary technology to Surface Power. It involves a system wide science called TDLF (thermodynamic laminar flow technology) coupled with MPPTt, (Maximum Power Point Tracking – thermal). Several patents cover this technology which has been developed to create high powered solar air conditioning and solar central heating systems.
You can see its performance in the samples of our live systems 24/7.http://www.surfacepower.com/live.html
The key thing to notice is the different power band, (kWhrs produced) that is the difference in temperature between the collectors and the cylinder/pool/heating system, etc. Normal solar systems go from +3C to +7C and switch on and off all day. Surface Power systems do not work like this, they operate a DELTA T of between +10C and +25C bringing much larger amounts of power in any given day; and can stay running ALL DAY. Even at a DELTA T of +15C, it is still cloudy and many times higher than the average of any of the 1st, 2nd or 3rd generation solar vacuum technology’s.
Here is a Surface Power SP501 solar collector, (we only have the one type, size, shape, tube quantity), why have more than 1 type of solar collector ?, you can’t improve on perfection…
THIS IS FOURTH GENERATION SOLAR VACUUM HOT WATER TECHNOLOGY AND ONLY AVAILABLE FROM SURFACE POWER.
Our best advice:
It is our job as manufacturer to provide you with open and accessible information to help you with your research into solar hot water. All systems shown are customer systems. In the year 2011, You should not have to buy a solar system based on theories, probabilities and hocus pocus, it should be based on fact and examples of real outcomes. We don’t TELL you what you “SHOULD” get, we SHOW YOU what you “WILL” get. Any educational questions can be put to our support desk 24/7 email@example.com
Sustainable Habitat – Buildings, Resources and Community.
Adapted from IN CONTEXT #14, Autumn 1986
CAN WE HUMANS FIND FULFILLMENT on the earth without destroying it? Can we design (or redesign) our buildings and communities so that we will leave a healthier world to our great-grandchildren? Can our appetite for food and natural resources be met in sustainable ways?
These are the questions at the heart of this issue. Exploring them will take us into areas like architecture, urban planning, energy use, agriculture, and community development.
These questions have been on a wild roller coaster of public interest in the past few decades. Before 1960, our society hardly even knew these questions existed. Then, in the ’60s and ’70s, “ecology,” “environment,” “population explosion,” and “energy crisis” all rapidly became common concepts. Spurred on by this attention and awareness, all kinds of people experimented with appropriate technology, solar energy, organic gardening and recycling. But then along came the Reagan Era, and media interest in these questions seemed to evaporate overnight.
What happened? Did the need for concern disappear? Hardly, but people grew tired of hearing the bad news. Was the media being manipulated? Probably, but we’ll fail to see the whole picture if we just blame special interest pressures for the shift in public interest. Had appropriate technology failed? No, but it didn’t fully succeed, either. Technically, it was a remarkable success story. Of course, there were lots of experiments that failed or proved uneconomical – that’s to be expected – but a great deal was learned about how to live more efficiently. Yet implementing these technical successes turned out to be a social and political problem, and that is where the appropriate technology movement got stymied.
Aware of this history, we decided to do this issue on “sustainable habitat” as a way to discover what has been happening with these questions since they lost the limelight. What we have found is more good news than we expected. On the technical side, many of the biggest success stories have ceased to be news because they have become so much just a part of normal life. Even more heartening, there are the beginnings of progress on the social/political/economic side. What might be called “appropriate community development” is starting to take shape.
Which is not to say that there are not still massive – and growing – problems. But it looks like we may be on the verge of a new wave of creative movement that will blend the best technical learnings from the 1970s with the kind of social and human system sophistication that must complement the technical.
We offer this issue as a small contribution to the emergence of this much needed new wave.
WORKING WITH POSSIBILITIES
Finding Home by Robert Gilman
A look at roots and possibilities for habitat
Solar Streets and Wilderness Alleys by Robert Loring
Transforming existing neighborhoods into sustainable habitats
Rebuilding Echo Hill by Bruce Coldham
An alternative approach to housing development design
How a Little Community is Born by Johannes Olivegren
Residents of a Swedish housing cluster designing their homes together
Living in a Bofaelleskab an interview with Hildur Jackson, by Diane and Robert Gilman
The impact of cluster housing on everyday life in Denmark
The Sacred Art of Building by Tom Bender
Reflections on the creation of harmonious living environments
FOOD AND ENERGY
Energy Update an interview with Amory Lovins, by Robert Gilman
Some surprising developments in power supply and demand
Mainstreaming Sustainable Agriculture an interview with Wes Jackson, by Robert Gilman
Strategies for putting our biological knowledge to work
Greening the Desert an interview with Masanobu Fukuoka, by Robert and Diane Gilman
Applying natural farming techniques in Africa
STARTING WHERE WE ARE
Four Steps to Self-Reliance an interview with Hunter Lovins, by Robert Gilman
The story behind Rocky Mountain Institute’s Economic Renewal Project
Up By Our Bootstraps by Vicki Robin
An interview with residents of a town recovering from economic collapse. Plus An EcoCity in the Making by Hal Rubin.
Manifesting Your Sustainable Habitat by Claire Garden
The future of your neighborhood could begin next Tuesday at 7 pm in your living room