Three Systems for renovated house
by admin on Jan.11, 2010, under Greencon, Greencon Product Range, Greencon Solar Water Heating Solutions, Greencon Thermosiphon Systems
This particular house was being renovated, and the client used the opportunity to reduce their consumption. Have a look, basically the servants quarters, main house and cottage are all being delivered super hot water from the solar thermal system.
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Thatch House means we have to make a plan
by admin on Jan.11, 2010, under Greencon, Greencon Solar Water Heating Solutions, Greencon Thermosiphon Systems
Thatch roves can prove to be difficult for solar thermal installations. When we use flat plate technology, the problem is with the grass on the roof rotting, so we have to build a stand that lifts the panel off the roof. With vacuum tubes the issue of fire hazard, is of concern. There is a possibility of refracted light bouncing off the tubes and igniting the grass that covers the house. In these circumstances we advise the client to look for a different area to install the system – like the garage roof or not thatched area. Look at this example of a solar system mounted on a stand next to the house: (click on image to enlarge),
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Thermosiphon Installation
by admin on Jan.07, 2010, under Greencon, Greencon Product Range, Greencon Solar Water Heating Solutions, Greencon Thermosiphon Systems
Honestly the best way to install a solar thermal unit. In this example one of our teams installed a vacuum tube system into the clients house. This was advised for various reasons, but mainly due to the fact that the customer receives partial sunlight due to tree interference and shadows that are cast at certain times in the day. The vacuum tubes with there increased efficiency can still produce the amount of heat required for the customers usage.
Essentially what the Greencon technicians had designed, was a pre-feed system. The client wanted to dramatically reduce the amount of electricity being used to heat there rather large domestic boiler. So we designed a system that fed the boiler with solar heated hot water.
The site was relatively treed, so we decided to go with vacuum tubes, for there increased efficiency.
Let the saving Begin.
Greencon Goes Mobile
by admin on Sep.03, 2009, under Greencon, Greencon Product Range, Greencon Solar Water Heating Solutions
Are you still a sceptic? Or do you lack the capacity to convince all around you that this is the future? Well then get Greencon to deliver a display unit at your workplace or complex. We have a number of units that can be delivered with “lecture” dates advertised on the units for all interested to come and learn. Mail : info@greencon.co.za to book a delivery date.
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CSP – The way forward
by admin on Sep.03, 2009, under Greencon, Greencon Technology Update
Despite their widespread use, solar technologies suffer the limitation of most renewable technologies: an unpredictable operating profile due to weather variations. However, using the highly efficient properties of molten salt for heat transfer, one technology insulates electricity production from weather volatility and, more importantly, it offers the capability to dispatch electricity as needed without requiring the use of natural gas. This technology is a concentrating solar power (CSP) technology, built around a proprietary central receiver tower and molten salt loop.
Thermal storage is widely regarded as the future for the renewable energy campaign because, unlike many intermittent renewable resources such as wind energy, it offers a “zero-emissions” technology with firm capacity and dispatchability characteristics. The thermal storage system provides an added benefit: allowing the plant to be designed to optimize the electricity load profile to meet specific market needs. A plant can be designed, for instance, to maximize electricity production during a period of peak demand or to continue to produce electricity after the sun goes down.
Figure 1 (left) illustrates how the thermal storage system can be utilized to “shift” electricity production to the peak demand period. Solar energy is collected when the sun begins to shine, but electricity is produced approximately 6 hours later in order to generate electricity during a period of peak demand. The red line represents direct solar irradiation, the solid blue line represents the production curve without storage and the dotted blue line represents the production curve with 6-hr storage.
Technology Description
Thermal storage technology uses a solar “power tower” design, which generates power from sunlight by focusing energy onto a tower-mounted central heat exchanger or receiver.
As shown in Figure 2 (above), a field of sun tracking mirrors called heliostats is used to reflect and concentrate the solar radiation onto the receiver (Step 1). At Solar Reserve’s Solar Two facility, molten salt is circulated through tubes in the receiver, collecting the energy gathered from the sun (Step 2). The hot molten salt is then routed to an insulated hot thermal storage tank where the energy can be stored with minimal energy losses (Step 3). When electricity is to be generated, the hot molten salt is routed to a heat exchanger (or steam generator) and used to produce steam at high temperature and pressure. The steam is then used to power a conventional steam turbine, generating electricity (Step 4). After exiting the steam generator, the molten salt is sent to the cold salt thermal storage tank (Step 5) and the cycle is repeated.
The salt is a combination of sodium and potassium nitrate, with a melting temperature of 460°F. In the liquid state, molten salt has the viscosity and the appearance similar to water. “In solar applications, molten salt is used for a number of practical reasons,” says Terry Murphy, Chief Executive Officer for SolarReserve, who along with others helped develop the molten salt technology at Rocketdyne. “Molten salt is a heat storage medium that retains thermal energy very effectively over time and operates at temperatures greater than 1000°F, which matches well with the most efficient steam turbines. Second, it remains in a liquid state throughout the plant’s operating regime, which will improve long-term reliability and reduce O&M costs. And third, it’s totally ‘green,’ molten salt is a non-toxic, readily available material, similar to commercial fertilizers.”
A primary advantage of molten salt central receiver technology is that the molten salt can be heated to 1050°F, which allows high energy steam to be generated at utility-standard temperatures (1650 psi minimum, 1025°F), achieving high thermodynamic cycle efficiencies of approximately 40 percent in modern steam turbine systems. This high cycle efficiency is maintained while allowing the use of dry cooling towers, which is important in arid states with the best solar potential. The molten salt heat transfer loop through the receiver is isolated from main steam temperatures and pressures, resulting in cost savings through the use of low-pressure salt piping. Finally, the system is designed to minimize the length of the molten salt loop to less than 2,500 feet, which is heat traced to prevent ‘freezing.’
Thermal storage systems using molten salt have been identified for use with other solar technologies, such as parabolic trough systems, which have been the dominant solar thermal technology installed to date. Trough plants will require an additional heat exchanger to transfer the energy from the working fluid to storage and to transfer the energy in storage back to the steam system. It is estimated that the additional heat exchanger required for a trough plant causes a loss in cycle efficiency loss of up to 7 percent. In addition, a trough facility that can only achieve a hot working fluid temperature of 700°F will require approximately 3 times the thermal storage volume to generate a given amount of electricity as an integrated thermal storage system which stores energy at 1050°F.
The high cycle efficiencies and flexibility available with a central receiver system and integral thermal storage provides a compelling offering to the renewable energy purchasers.
Source: Renwable Energy World
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Economic Review of the International PV Industry
by admin on Sep.03, 2009, under Greencon, Greencon Product Range
Even without the expected decrease in demand in 2009, technology revenues would be lower than the US $20.4 billion (€14 billion) of 2008 as cell and module prices are around 40% below 2008 levels. Figure 1 (shown below) provides technology revenues from the manufacturer to the first point of sale in the market from 2003 through 2013. For 2009 and 2010, an estimate of revenues for the recession forecast has been provided. With technology prices at the current level, even growth in sales volume, which is highly unlikely, would result in lower revenues in 2009.
Figure 1. Worldwide module revenue volume for recession, conservative and accelerated growth models 2003-2013.
Accelerated growth in the photovoltaic industry continued in 2008, with 79% market growth over the previous year to 5.5 GW. Unfortunately, the market was significantly oversold in 2008, stranding around 2 GW of product in supply side inventory at the beginning of 2009.
Most of the overselling was into Spain, which with a market volume coming in at 2.3 GW in 2008, represented 42% of total photovoltaic system sales worldwide. Along with high prices for modules and PV systems, quite a few instances of poor module product and poorly constructed systems, and permit speculation, the oversold market led the Spanish government to alter its support programme. The new decree capped the market, lowered the feed-in tariff and effectively closed Spain to new product sales for perhaps two years, or more.
Other than Germany, the PV industry currently has no other global market capable of accepting a volume of sales remotely similar to Spain. Moreover, the global recession and financial crises have further hobbled an industry that had been enjoying accelerated growth since 2004. For these reasons, the PV industry is set to experience its first decrease in demand in more than 30 years — and not just flat growth, but a decrease in sales volume of perhaps 30%, or even more.
Figure 2, (below), provides data for 35 years of PV industry growth, from 1974 through 2008, while Figure 3, (below), reveals three forecast scenarios for 2009, which are on based on assumptions related to recession, conservative and accelerated growth for the sector.
Though the PV industry enjoyed accelerated growth from 2004 through 2008, this rate will not continue in 2009, and accelerated growth is unlikely into 2010. In 2009, lending from the international debt markets continues to be depressed. Meanwhile, the loss of a major market — Spain — is having a deleterious effect on growth, inventories remain high, and global economies remain in recession.
Figure 2. Photovoltaic industry history 1974-2008 (CAGR = compound annual growth rate).
Furthermore, although market development is underway, Germany remains the only market capable of consuming more than a gigawatt of product, and other markets, such as Italy, are underperforming. Japan, South Korea, the United States and others continue to experience slow growth. The good news is that module prices in the soft market seen in 2009 continue to decrease significantly.
As previously noted, while the PV industry has experienced slow or flat growth so far this year — to July 2009 — it is an industry that has not experienced negative growth in 35 years or more. Conversely, years of significant strong growth of more than 70% include: 1975 at 150%, 1976 at 141%,1977 at 87%, 1978 at 112%, 1980 at 128%, 1983 at 88%, and 2008 at 79%.
Since 1974, the PV industry has only experienced three years of soft growth, defined here as demand growth of less than 10% in a given year: 1986 at 8%, 1993 at 3% and, 1994 at 10%.
The Incentive Driver
Historically, the PV industry has enjoyed strong growth, though at much lower volumes than today. The strong growth that the PV industry enjoyed since 2004 was driven by incentives, in particular, the feed-in tariff laws in Europe, and even more specifically, Spain’s generous programme. Though for countries in Europe (in general) there is no reason to assume that feed-in tariff programmes will stop altogether, the problems experienced in Spain (overselling, fraud and poor quality products among them) are having a sobering effect on government incentive planning in other EU countries. The support programmes of the future will need to include mechanisms that manage growth along with stimulating it.
The incentives that the industry relies on come with downward price pressure, which is a significant constraint. However, given the goal of grid parity, there is literally nowhere for price to go but down. Grid parity, nonetheless, is a complex subject, differing in most global markets. Moreover, grid parity provides a level competitive playing field for solar (a worthwhile goal on its own), but does not ensure success.
The industry also needs an increasing number of highly trained installers, sales personnel, engineers and such like, and this comes at a cost. Lower costs and prices are necessary for the continuation of incentives and, therefore, demand. For accelerated growth to continue, and for the eventual slowing of demand to happen gradually, unlike the expected steep decline in 2009, the PV industry must learn to manage its demand. It must develop incentives with triggers to control demand when it accelerates too quickly.
The industry must also control its supply chain from expensive raw material, to consumables, and through to the end user, and must participate with balance of systems (BOS) manufacturers to innovate and develop inexpensive and robust BOS. All raw materials, consumables and machinery are more expensive at this point because of the higher price of oil, which is necessary for transportation.
Other caveats to limitless growth are the high price of PV systems, and the availability of less expensive alternatives, including conventional energy sources such as natural gas and coal. In recent years, the current high volume of industry demand, coupled with raw material shortages, threw the industry into a panic. Instead of the technology standard, ‘if we build it they will come,’ the new mantra became, ‘they are coming and we can’t build it.’
The industry reacted by buying silicon feedstock and cell futures, and by raising component (module) and system average prices, globally. These long-term contracts for raw material, wafers and cells are proving unsupportable and in many cases, are being rewritten or ignored.
Figure 3. Recession, conservative and accelerated forecast scenarios for grid-connected PV, 2008-2013.
The Past Can Inform the Future
It is useful to study specific periods in the PV industry’s history, in terms of growth and drivers for growth, to see what can be learned from these periods which can be useful in understanding the direction of this still young industry. Figure 2, offers compound annual growth rates for the PV industry for specific periods, 1974–1984, 1984–1994, 1994–2004 and 2004–2008.
During 1974–1984, strong compound annual growth of 84% was due to utility and government-backed grid-connected demonstration projects. During this period, the grid-connected application was 30%–50% of total demand, though from annual totals less than 20 MW. Following this decade-long period of significant growth, lower compound annual growth of 13% for 1984–1994 was due to an almost complete cessation of these projects. During this period, grid-connected applications (primarily unsubsidized or incentivized) was less than 10% of annual demand.
Stronger compound annual growth of 33% during 1994–2004 reflects the beginning and continuation of the strong incentive programmes that continue to drive PV industry growth. Specifically in Europe, the feed-in tariff model has proven to be the most successful incentive model. Japan’s residential rooftop programme in the late 1990s, a capacity subsidy, built a sustainable market for solar roofs in that country. In the US, incentives in California created the most significant market in that country.
The 2004–2008 period also managed to encompass two significant events for the sector: the PV industry’s greatest raw material (silicon feedstock) shortage and its strongest period of sustained accelerated growth.
During this period, demand for large field grid-connected applications in Europe, largely driven by the feed-in tariff model of incentives, created the largest global market (79% in 2008) for solar systems. However, the solar-grade silicon raw material shortage that had pushed up prices for crystalline silicon modules also created an entry point for thin-film technologies, which had previously been viewed as risky. The industry’s compound annual growth for this period was 51%.
Grid-connected Growth Drivers
Like it or not … strong growth in the PV industry comes with strong growth in grid-connected applications. Off-grid (remote) applications show slow, steady growth over time, but have not driven the industry into gigawatt sales. It is the grid-connected applications (residential, small, medium and large commercial, large field commercial and utility) that dominate the market for photovoltaic modules. Indeed, at 94% of total sales in 2008, the volume of grid-connected installation leaves very little module product available for off-grid applications.
The grid-connected application remains driven by government subsidy/support programmes (Europe’s feed-in tariffs, US rebates, for example). Without such programmes the market for grid-connected PV products would decrease dramatically. The significant decrease in demand in 2009 is a lesson to the industry about the significant changes that could take place in demand, revenues and profitability when markets are abused, and when so-called ‘black swan’ events, such as the global recession, alter the playing field and force reactive market and price setting.
Figure 3 (shown above) offers an aggregate five-year forecast for grid-connected applications. The recession forecast is presented in Figure 3, but is considered a two-year anomaly. Meanwhile, Figure 2 excludes off-grid applications. However, at more than 90% of the total market demand, the volume of grid-connected applications effectively represents the total industry volume.
All is not doom and gloom, however, with encouraging current market developments in the US and some other countries. There is continued progress in lowering manufacturing costs so that a reasonable margin can be maintained along with lower system prices. We see progress in increasing efficiencies for all technologies, and business model innovations, meaning that accelerated growth will resume for the PV industry. Certainly, at this stage in PV industry development (which could be likened to its preadolescence) there is room to grow and much to learn before a stable, sustainable level of annual growth settles in. Until then, exciting, and sometimes painful times remain ahead.
Source: Renewable Energy World
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Energy saving advice from old guard
by admin on Aug.11, 2009, under Greencon, Greencon GreenBuilding Research
A quarter-century ago, in the wake of America’s first energy crisis, a young scientist named Amory Lovins came to the Rocky Mountains and built himself a radical house based on a radical idea. The country could save both energy and money, he believed, by combining common sense and unconventional technology.
Mr. Lovins did achieve substantial energy savings, and many of his innovations, from better insulation to multiple-pane windows to more-efficient refrigerators, eventually became familiar fixtures in American homes….
Now, Mr. Lovins has completed a renovation that he hopes will demonstrate how much more energy-efficient houses can become. But the project also serves as a reminder of the still-enormous gulf between what is technologically possible and what society is able or willing to pay for….
Some of his proudest advances stem from mundane changes. He installed an electric stove made by a Swiss company that is 60% more efficient than other models he found. The savings stem partly from pots designed specifically for the stove. The pots eliminate warping that typically occurs with copper cookware, wasting heat.
He also has shaved energy use by insisting on an unconventional plumbing design. Typically, residential pipes that carry water would be ½-inch wide and turn at right angles. But that builds up friction, requiring electric pumps to work harder to propel the water. So Mr. Lovins had ¾-inch-wide pipes installed that run diagonally across ceilings and walls to minimize friction.
“If it looks pretty,” he says, “it probably doesn’t save energy.”
Source: Climate Progress
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Populations preparing to be moved
by admin on Aug.11, 2009, under Greencon, Greencon International News
Some Pacific Island states are preparing their populations for relocation if climate change claims their homes, and New Zealand appears to be more willing than Australia to accept them.
The impact of climate change on the Pacific was a hot topic at the Pacific Islands Forum leaders summit in Cairns today.
Australian Prime Minister Kevin Rudd told reporters it was necessary to be blunt about priorities.
The first step was to minimise the impact of climate change, internal relocation was the next consideration and if that failed “a wider international response” would be required.
He stopped short of confirming Australia would be willing to accept people displaced by climate change.
Prime Minister John Key said New Zealand would support countries if it came to relocating people.
“It would be my hope that we would never come to that,” he said.
“You’re talking about countries being submerged and I haven’t seen any advice that that is an imminent likelihood.”
Vanuatu Prime Minister Edward Natapei said his country suffered from cyclones, earthquakes, volcanic eruptions and tsunami.
Two years ago an entire village had to be relocated inland because homes were under water.
However, Mr Natapei said not all of Vanuatu was low-lying and people could be relocated internally. His country would need assistance to do that.
For Kiribati it was a different story, with the government there working to educate and train people so they can move overseas if disaster strikes.
“We are very proud people and my government does not want the people of Kiribati to be relocated as refugees,” Kiribati Secretary of Foreign Affairs Tessie Lambourne told reporters.
Mr Rudd said climate change had dominated today’s talks and coincided with the release of a report his government had prepared.
The report referred to the particular vulnerability of Pacific Island states to climate change and the need for global action, supporting those nations to build climate resilience and sustainable development.
With 50 percent of the population in Pacific Island states living within 1.5km of the coastline, rising sea levels were not an abstract idea, Mr Rudd said.
Australia would support “practical measures” to help Pacific Island states adapt through taking the Pacific’s situation to the world, ensuring better coordination and acting on behalf of the region.
Mr Key said the threat to those countries was why New Zealand was taking climate change seriously.
Niue’s Premier Toke Talagi said climate change was a “real problem” in the Pacific and one which “if not reversed, threatens our livelihoods”.
Smaller island state leaders have called on developed nations to commit to significant emissions reductions to help prevent climate change.
Source: National Business Review
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Green Shopping Malls
by admin on Aug.11, 2009, under Greencon, Greencon GreenBuilding Research, Greencon Solar Technology Update
There are roughly 85,000 supermarkets in America. Generally speaking, they are artificially lit boxes surrounded by dark asphalt and contain row upon row of doorless display refrigerators. There is, to say the least, room for improvement. Hannaford, which has about 160 supermarkets in the northeast, decided to try something completely new and on July 25th opened the first LEED Platinum certified supermarket, which is located in Augusta, Maine. With Maine’s governor, John Baldacci, in attendance, the plaque was personally awarded at the opening by Rick Fedrizzi, president of the USGBC.
The project began two and a half years ago, and Hannaford (owned by the Belgian Delhaize Group) knew that they would have to go outside of their traditional competencies. Fore Solutions was hired to help facilitate the integrated design process.
Creating strategies to meet sustainable goals offered some surprises. The use of ice to display fish turned out to be a huge source of energy and water waste. Fore Solutions principal, Gunnar Hubbard, said, “the ice takes a lot of energy to create, then, after a day of having fish lie on the ice, you have to get rid of it, so you take hot water and melt it away. There’s the energy to create the ice, the water to make the ice and the energy and water for the hot water to get rid of the ice at the end of the day.“ Using ice-less display cases takes that out of the equation and the fish still look good enough to eat.
The finished product is a grocery store that will serve as a laboratory for sustainable improvement at other Hannafords — and possibly industry-wide. It will use 50% less energy than a typical supermarket and 38% less water. Green features include:
- 7,000 square foot green roof;
- Highly reflective asphalt in the parking lot to reduce heat island effect;
- Low-flow toilets and faucets and waterless urinals;
- 41 kW solar array (the largest in the state of Maine);
- Ice-less cases in the seafood department;
- Geothermal heating and cooling;
- Over 70% of the wood used is FSC certified;
- Reclaimed heat from GreenChill refrigeration system provides interior heating;
- Interior surfaces made from recycled materials;
- Windows, a clerestory, skylights and solartubes provide natural light;
- An advanced recycling program for store cardboard, plastics, paper, light bulbs, and batteries, as well as a recycling center for shoppers;
- Almost all freezers and coolers have doors, which creates a consistent indoor temperature; and
- When daylighting is at its maximum, most of the electric lighting automatically turns off.
In addition, 96% of the demolition debris and 99% of the contents of the building (a closed high school) was recycled or reused.
Source: Jetson Green
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Green conversions to existing structures
by admin on Aug.11, 2009, under Greencon, Greencon GreenBuilding Research
Southern Liberties, LLC, recently completed a massive overhaul of this Philadelphia rowhouse and documented the process on the blog, Building Green on Montrose. The 100-year old, 1,850 square foot home now has three bedrooms and two and a half bathrooms, and the owners hope to obtain LEED Platinum certification for their efforts. It’s listed for sale at $565,000 and incorporates some of the following green strategies:
- Vegetated green roof;
- Salvage of part / deconstruction of the rest of the original structure;
- Waste recycling during construction;
- FSC Certified woods used throughout;
- Recycled content metals used throughout;
- Pervious paving and rain water catchment system;
- High efficiency HVAC system;
- Energy-efficient windows placed to allow natural lighting;
- Zero VOC paints and stains, no carpet;
- Efficient spray foam insulation used on exterior walls; and
- Low-flow fixtures and Energy Star appliances.
First noticed at Re-nest.
Photo credits: Building Green on Montrose.
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