Thursday, March 28, 2013

Solar closet calcs from Nick Pine

Solar closet economics

Subject: Solar closet economics
From: (Nick Pine)
Date: 6 Apr 1995 09:19:04 -0400
Article: 93 of
chitecture.alternative: 2753
Newsgroups:,, alt.architecture.alternative
Organization: Villanova University
Summary: Pretty good, vs "conventional passive solar houses"

This is a rough estimate of the payback period for three houses, counting
only materials costs and annual energy costs, ignoring labor costs and the
time value of money...

House (a) is a conventional 2000 ft^2 two-story frame house, about 32' on
a side, with R30 insulation, 20% R4 window area on each wall, and 0.5 air
changes per hour, in the Philadelphia area. It has a sum of R-values divided
by surface areas of approximately

SAR = (32x16x4+1024 ft^2)/R30 +0.2x32x16x4 ft^2/R4 = 100 +100 = 200,

and an air infiltration rate of about 0.5 x 16,000 ft^3 = 8000 ft^3/hr,

so the average annual space heating requirement is about

5500 degree days x 24 hr/day x (200 + 8000 ft^3/hr/55 ft^3/Btu-F)

= 5500 x 24 x (200 + 150 ) = 46 x 10^6 Btu/year,

or about the same as the heat contained in 450 gallons of oil, burned in an
old, 70%-efficient oil burner.

In addition, this house needs the heat equivalent of about 400 gallons of oil
per year for domestic water heating, which would cost about $1200/yr, with an
electric water heater, using electricity at 10 cents/kWh. This house uses the
heat equivalent of about 850 gallons of oil per year, altogether. Its oil
burner has an infinite payback period, for comparison with the next two houses.

House (b) is the same house, as redesigned by an architect, as a typical
"passive solar house." It might use 30% less oil than house (a) for space
heating, with 50%, vs. 20% south wall window area, and a masonry floor
in front of the south windows, or a double layer of drywall for additional
thermal mass in the house, at an additional cost of about $10/ft^2 for the
additional windows and thermal mass. The savings here is about 150 gallons
of oil/year, vs. house (a), and the additional cost of the house is about

30% x 512 ft^2 x $10/ft^2 = $1500 for the windows, plus
50% x 1024 ft^2 x $10/ft^2 = $2500 for the floor.

Ignoring the time value of money, the payback would be about

$4000/(150 gal/yr x $ 0.7/gal) = 40 years,

or perhaps less if the floor is concrete, vs. tile, granite or marble,
which is good, compared to case (a).

House (c) is the same house as redesigned by a residential passive solar
HVAC engineer, with a 4' wide x 16' long x 8' tall solar closet, behind some
clear polycarbonate solar siding, an air heater measuring 24' wide x 16' tall.
Both the closet and air heater would have plastic film dampers to prevent
reverse thermocirculation at night. House (c) might use 90% less energy than
house (a) for space and water heating, at an approximate additional cost of

64 ft^2 x $10/ft^2 = $640 for the solar closet, plus
$200 for a small pump and water-water heat exchanger.

The polycarbonate siding might replace vinyl siding _and sheathing_, and the
greenhouse shadecloth and 3 1/2" insulation in the south wall might replace
5 1/2" of fiberglass insulation. The solar closet would have 3 1/2" of
insulation all around it, and it would contain 32 55 gallon drums full
of hot water, as a sort of stagnant, inefficient solar collector, BUT most
of the lost heat from the closet would go into heating the house. The air
heater wall would provide heat for the house on an average day, in January,
with some sun, and the solar closet would operate in "standby mode," until
its stored heat were needed to heat the house during a string of cloudy days.
Depending on the geometry, the solar closet might have a small, high
temperature fan to help with natural convection, and a horizontal reflective
surface in front of it, eg a white-painted surface or shallow reflecting pond.

The solar closet would also provide hot water for the house, using a couple
of plastic drums on top of the 4 high x 8 wide drum stack as air-water heat
exchangers. These bunghole drums would be plumbed together in series, and
low-pressure, high-temperature solar water would be circulated with a pump
through a loop with a water-water heat exchanger located below a conventional
electric water heater. If the electric water heater were located in or above
the solar closet, the pump might not be necessary. In any case, electric water
heating would seldom be necessary.

The solar closet would be inexpensive floorspace, about 3% of the house area.
It might have a dirt floor, with the drums sitting on a piece of polyethylene
film on the dirt, with each drum supporting the one above it. The rectangular
array of drums might be lightly supported by the closet endwalls, to keep it
from tilting. The inside walls of the closet might be the foil face of the
fiberglass insulation. The outside walls of the closet, inside the house,
might be drywall. The closet might have a small electrical air damper with a
thermostat to control it, to let warm air heat the house on cloudy days. The
closet could be extended a bit on one end to make a sauna or "warm room,"
for clothes drying or food drying.

So here we seem to have an additional cost of materials, over case (a)
of about $840, (if the air heater replaces part of the normal south wall,
at the same or lower cost.) The payback period would be approximately

$840/(90% x 450 gal (space) + 400 gal (water)) x $ 0.70/gal)

= $840/$535 = 1.5 years, or less, if water were heated electrically.

Now you might also ask, "Will this work, as described?" I think so, but
I haven't tried it, yet. That's an enginering question that can be answered
by experiments and caclulations involving heatflow. The new Conserval wall is
a thin, unglazed sheet of aluminum, painted black, with about 2% of its area
as 1/32" holes, with air flowing through the holes. It has a measured solar
collection efficiency of 80%, which seems encouraging.


Tuesday, March 26, 2013

France: High Solar Thermal Standing, But Shrinking Market | Solarthermalworld

France: High Solar Thermal Standing, But Shrinking Market | Solarthermalworld

Having been asked by French Environment and Energy Management Agency, ADEME, to identify market barriers and set research priorities, about twenty sector professionals came together to publish a roadmap in late 2012 (see the attached document in French). The roadmap outlines today’s tough situation: installations are too expensive, too complicated and take too long to install. For example, the installation of a solar water heater in a single-family house needs a full four days.
The roadmap’s 2020 aim is to reduce costs by 50 to 80% per kWhth. It recommends penetrating the market with compact systems, which reduce installation work. “Our idea is to optimise the collector surface to better meet the customer’s needs, for example, by using a kit with a 2 m² panel and a 100 to 150 litre water tank,” says Philippe Gay, Mission Coordinator at French solar industry association Enerplan. Using an all-in-one compact system for homeowners is also a way to facilitate the installation. “These compact systems combine a solar water tank and a boiler in one box. They have been on the market for several years, but we have recently seen a growing interest in installations in multi-family houses,” explains Yves Carl, Marketing Director of German solar thermal company Viessmann in France. According to Uniclima, the French union for the heating, cooling and ventilation industry, compact systems account for about 20% of the solar thermal water heater market for single-family houses.

World's 9th Most Powerful Supercomputer Won't Cure Cancer, But Will Find Oil Super Fast | ThinkProgress

World's 9th Most Powerful Supercomputer Won't Cure Cancer, But Will Find Oil Super Fast | ThinkProgress

Global oil and gas exploration and production costs are expected to rise again to $644 billion in 2013, according to an annual survey by Barclays. These fuels are getting increasingly expensive and difficult to produce, requiring massive computational power to find a way to squeeze more dinosaur juice out of the Earth’s crust. The climate clock is ticking, and it is worth asking if such investments in oil & gas extraction are worth it. Pierrehumbert again puts the scenario plainly:
Whales were driven to the brink of extinction before petroleum replaced whale oil, and we may well fry our planet—and bankrupt ourselves while doing so — before we’re finally forced to kick the fossil fuel habit. It will be hard to muster the resources to develop replacements for fossil fuel energy if we wait until both the economy and climate are in ruins. We are in for a hard landing if we don’t use our current prosperity to pave the way for a secure energy and climate future.
That includes using recent powerful technological advances to get ourselves off fossil fuels and onto renewables.

Saturday, March 23, 2013

Will Alternative-Energy Growth Tank During New Fossil-Fuel Glut? [Slide Show]: Scientific American

Will Alternative-Energy Growth Tank During New Fossil-Fuel Glut? [Slide Show]: Scientific American

This has happened more than once before, suddenly low energy prices kills off clean alternatives,  this is real bad news..

The alternative energy landscape is in tumult, judging by the recent fourth annual summit of the Advanced Research Projects Agency for Energy, or ARPA–E. A glut of cheap natural gas threatens to sweep all other energy sources before it. The so-called "shale gale," as Alaska Sen. Lisa Murkowski put it at the recent ARPA-E energy summit, is forcing a rethink of energy strategy. "Before this so-called shale gale came upon us, groupthink had most of us focusing on energy scarcity," Murkowski noted. "The consensus now is that we have abundant energy. We can't fall into the trap of groupthink again."

Funding for alternative energy—whether from the federal stimulus bill or venture capitalists—has dried up. "We're here because it's ARPA–E, and they have some resources," says Saul Griffith of OtherLab, a research and design firm that has received funding from the agency for researching uniquely shaped tanks for natural gas. "We all suffer from a lack of resources. We all have ambitions that want to go faster and bigger." Or as retired Marine Corps Gen. James L. Jones put it as part of a talk about the link between national security and energy security: "A vision without resources is a hallucination."

More than 250 exhibitors came to show their wares alongside ARPA–E efforts ranging from Smart Wire Grid's power-flow controllers for electricity transmission lines to OPX Biotechnologies's modified microbe that builds liquid fuels from hydrogen and carbon dioxide. "After three years have there been home runs?" asked retiring Secretary of Energy Steven Chu at the summit. "Maybe not, but there are people rounding second or third base."

Friday, March 22, 2013

Michael Northrop: Let's Count the Ways Keystone Approval Helps Us: Memo From Houston

Michael Northrop: Let's Count the Ways Keystone Approval Helps Us: Memo From Houston

So, why do we want President Barack Obama and Secretary John Kerry to approve construction of the Keystone pipeline from Alberta to the Gulf of Mexico?
• Because it will allow Canada to double and then triple production of tar sands and send it to thirsty Asian consumers.
• Because it will encourage Wall Street to increase investment in tar sands mining; they're worried now that increased amounts of tar sands can't get out of Canada without more pipeline capacity. All the other new pipeline routes are currently being blocked by citizen campaigns in Canada and the U.S.
• Because, if we wait too much longer, Americans will realize this has nothing to do with U.S. energy security. In reality, only a small portion will be used in the United States. Oil companies can get a higher price for these fuels in Asia.
• Because it will allow Canada to say once and for all that it is no longer possible for their country to commit to a national greenhouse gas reduction target.
• Because it will create a strong incentive for Canada to continue obstructing international climate negotiations. Canada definitely doesn't want to look like a laggard if others are moving forward. Far better to continue slowing the international process as it has been doing the last eight years.
• Because it will embolden Canadian oil industry and government representatives to continue interfering with American clean energy policymaking that offers incentives for cleaner fuels and vehicles.
• Because it will provide additional momentum to Canadian efforts to lobby Europeans against passing a clean fuels directive. If the Americans don't take a stand, it will be harder for the Europeans to stick their necks out.
• Because it will embolden Canada's current government to continue cracking down on Canadian civic interests and companies, who are opposed to tar sands development.
• Because it will strengthen Canada's determined march to becoming a major petro state.
• Because once it is unstoppable, people will stop worrying about runoff into the North Canadian Athabascan watershed, or the increase in cancers in indigenous peoples living downstream; these are a small price to pay for billions in tar sands revenues.
• Because the economic benefits will overwhelm the costs of inevitable pipeline spills of nearly impossible-to-clean-up tar sands bitumen across more than 1,000 miles of American territory.
• Because it will create social license for deforesting an area the size of Florida and turning it into the globe's largest open pit strip mine.
• Because it will provide 3,900 temporary jobs for oil pipeline construction while undercutting electric vehicle and alternative fuels markets being developed south of the border; god forbid those industries take off before we can get the tar sands deposits out.
• Because it will take the wind out of the sails of America's first real citizen climate movement (that demonstration on the mall was worrisome), and reduce pressure on President Obama to be bold on climate change and clean energy during his final term in office.
• Because it will dampen enthusiasm among a large number of Obama voters, supporters, and donors, who are alarmed about climate change and who have let it be known that they don't want this pipeline built; this will further disempower pro-environment democrats contemplating clean energy and climate policy.
• Because it will put a damper on clean energy investment in general.

Monday, March 18, 2013

Parabolic solar reflectors - Solar Cooking

Parabolic solar reflectors - Solar Cooking

Single and compound curves

A lot of difficulty is encountered in the fabrication of parabolic reflectors, even with thin sheets of steel, since a paraboloid is a "compound curve", which cannot be made simply by bending a flat sheet of metal. To make a paraboloid exactly, the metal has to be stretched, which is difficult to do with simple equipment. Many fabricators have presented methods to make the construction of a parabolic shape easier by doing it approximately. Srinivasan (1979) proposes a method wherein a circular sheet was cut out into suitably shaped petals, each of which is a "single curve", which can be made by bending a flat sheet., The dimensions of the petals are carefully arrived at after detailed calculations. The petals are then joined to form the parabola, But this method too was found rather difficult, especially cutting out ‘curved petals’ from the sheet.

Fabricating Parabola from a single plane.

So, a simpler method has been proposed – (Concept I) by Ashok Kundapur– which involves cutting the circular (1-1.5 m diameter) GI sheet or aluminium into ‘petals’ with straight cuts which is easier. Large sheet of one to one-and a half m diameter is taken. Center is marked and a small circle of 15 cm in drawn from this circle. Then up to to 8 or 16 lines are drawn to the perimeter of the outer circle from the center (radius). 5 mm holes are drilled at the junction of this inner circle and the line of straight cuts. This would assist in easier overlapping (Figure 4). Then, the ‘petals’ are fixed overlapping one another, only at the edge. The width of this overlap was calculated using standard formulae (Baumeister et al. 1978; Kundapur 1995). Recently Mikes site mentioned above give more accurate dimensions of the over lap, one need enter just the number of 'petals' and length of focus in his chart and lo ! the width of overlap shows up. Once you get the values of over lap, drill small holes at the outer periphery of circle just adjacent to the radial lines based on the width of over lap so as to aid in joining of the 'petals'. Also drill a 5 mm hole in the center of the circle. Now cut the circle into petals along the radial li e perfected by pushing or pulling at the hole at the center of parabola. When finished, the parabola has to be fixed to a frame work made of Steel or Aluminium flats. The frame work has to be fixed on to a U shaped stand. (see following Figure for details). The petals are marked as 1 & 2, first

(Please await diagram)

Mechanical Mathematician

Mr Genevieve of France has described a simple way to form a parabolic dish. either from cardboard panels or with mud. He made both. He calls it the Mechanical Mathematician. has a super applet that shows the principle really well. In practice, a setsquare cannot be used as it would go through and destroy the parabolic shape! The mechanical mathematician makes use of the principle but does not go through the parabolic dish.So a dish can be made directly. It has several advantages. No math needs to be calculated and the material for making the mathematician can change depending on what is available. In practice, a The focal length can be changed really quickly to suit the material used. It can be set up on site pointing in the best direction, etc. find more on the web about it, mechanical mathematician and cob can be searched. Here is a simple animation to show how it works.

The Best USB battery pack for travel | The Wirecutter

The Best USB battery pack for travel | The Wirecutter

TUAW’s Kelly Hodgkins touted the Energy Station 10000’s long lasting power, saying “On more than one occasion, I charged my iPad to an acceptable level and then handed the Satechi to my husband who used it to charge his iPhone while he was away for the morning. When he returned, I could then finish off the iPad charge cycle and still have 20 percent left on the power pack.”
GottaBeMobile’s Kevin Purcell was also impressed by what the Energy Station 10000 had to offer, noting that he “…I tested the Satechi 10000 mAh Portable Energy Station by charging up my Samsung Galaxy Note to 100 percent and charging the Satechi to 100 percent. I plugged my Note into the Satechi and then used it heavily. With the Note’s battery and the Satechi’s battery my phone lasted for over 30 hours. My Note normally lasts 6-8 hours by itself, so the Satechi gave me another 22 hours of battery life. That’s saying something since few charging solutions can charge the Note when used the way I normally use it.”
Gadling’s Kraig Becker called the battery a great travel option and said it was “small, lightweight and highly packable.” There were also favourable reviews for the Energy Station 10000 from Gadget Review, Tech Reaction,, and travel site Vagabond Dish.
The Wirecutter’s own Brian Lam owns one too. In one of the emails he shot me after finding out that the Energy Station 10000 proved to be the best pick out of everything I tested, he told me “I love the Satechi, by the way. It packs really well. The square ones piss me off. The other great thing about the it is that you can stand it up in a bag pocket and the plugs hang out the top.” So there’s that.
But it’s Not Perfect
There were a few things about it that I didn’t like.
For starters, the battery’s relatively light weight comes at a cost: Its shell is made entirely out of plastic. While that’s not a deal-breaker, the fact that the plastic is of a particularly light and cheap feeling variety makes me wonder how well it’ll stand up to wear and tear. I can tell you that its shiny black and silver surface are a fingerprint and scuff magnet. But this doesn’t negate any of the thing’s functionality, so not a big deal.
Slightly more annoying is the fact that it uses mini USB instead of the now-ubiquitous micro USB. It's better not to have to carry multiple different types of cables and if your cables work interchangeably between devices, all the better in case you lose one.
I also don’t like the fact that the charging adapters that it comes with are so small and easy to lose. Satechi includes a drawstring pouch that’ll hold the battery and all of its various cables and bits, but meh, it feels cheap. It likely won’t matter though. If you’re anything like me, you’ve got more than one cable to charge your favourite devices with, so the cable and adapter heads that the Energy Station 10000 ships will will likely wind up in a drawer a few days after you buy one.
Furthermore, in dim light, and in direct sunlight, I found it hard to read the text under the USB ports that tells you which was the low-powered port and which was the high-powered one. But I think we can file that under nit-picking.
It should be noted that while I didn’t have any issues with the Energy Station 10000 during testing, iLounge’s Nick Guy did. He had a hard time getting the battery to take a charge with its included accessory cable, had issues with its charge indicator lights and felt, given the Satechi’s charging time, that it wasn’t actually providing a full 2 amps of power from its USB ports. I reckon Nick must have wound up with a defective unit, given that the rest of the editorial reviews for the Energy Station 10000 are overwhelmingly positive. I did manage to find an Amazon customer who felt that he was only getting maybe 5000mAh out of the battery, but he was willing to admit that he may very well have received a unit with a dud cell or two.

Thursday, March 14, 2013

Phoenix may not survive climate change -

Phoenix may not survive climate change -

Longer term, the Colorado River poses issues that no amount of tribal water can resolve. Beset by climate change, overuse, and drought, the river and its reservoirs, according to various researchers, may decline to the point that water fails to pass Hoover Dam. In that case, the CAP would dry up, but so would the Colorado Aqueduct which serves greater Los Angeles and San Diego, as well as the All-American Canal, on which the factory farms of California’s Imperial and Coachella valleys depend. Irrigators and municipalities downstream in Mexico would also go dry. If nothing changes in the current order of things, it is expected that the possibility of such a debacle could loom in little more than a decade.
The preferred solution to this crisis among the water mavens of the lower Colorado is augmentation, which means importing more water into the Colorado system to boost native supplies. A recently discussed grandiose scheme to bail out the Colorado’s users with a pipeline from the Mississippi River failed to pass the straight-face test and was shot down by then-Secretary of the Interior Ken Salazar.
Meanwhile, the obvious expedient of cutting back on water consumption finds little support in thirsty California, which will watch the CAP go dry before it gets serious about meaningful system-wide conservation.
Burning Uplands
Phoenicians who want to escape water worries, heat waves, and haboobs have traditionally sought refuge in the cool green forests of Arizona’s uplands, or at least they did until recently. In 2002, the Rodeo-Chediski fire consumed 469,000 acres of pine and mixed conifer on the Mogollon Rim, not far from Phoenix. It was an ecological holocaust that no one expected to see surpassed. Only nine years later, in 2011, the Wallow fire picked up the torch, so to speak, and burned across the Rim all the way to the New Mexico border and beyond, topping out at 538,000 charred acres.
Now, nobody thinks such fires are one-off flukes. Diligent modeling of forest response to rising temperatures and increased moisture stress suggests, in fact, that these two fires were harbingers of worse to come. By mid-century, according to a paper by an A-team of Southwestern forest ecologists, the “normal” stress on trees will equal that of the worst megadroughts in the region’s distant paleo-history, when most of the trees in the area simply died.
Compared to Phoenix’s other heat and water woes, the demise of Arizona’s forests may seem like a side issue, whose effects would be noticeable mainly in the siltation of reservoirs and the destabilization of the watersheds on which the city depends. But it could well prove a regional disaster.  Consider, then, heat, drought, windstorms, and fire as the four horsemen of Phoenix’s Apocalypse. As it happens, though, this potential apocalypse has a fifth horseman as well.
Rebecca Solnit has written eloquently of the way a sudden catastrophe — an earthquake, hurricane, or tornado — can dissolve social divisions and cause a community to cohere, bringing out the best in its citizenry. Drought and heat waves are different. You don’t know that they have taken hold until you are already in them, and you never know when they will end. The unpleasantness eats away at you.  It corrodes your state of mind. You have lots of time to meditate on the deficiencies of your neighbors, which loom larger the longer the crisis goes on.
Drought divides people, and Phoenix is already a divided place — notoriously so, thanks to the brutal antics of Maricopa County Sheriff Joe Arpaio. In Bird on Fire: Lessons from the World’s Least Sustainable City, Andrew Ross offers a dismal portrait of contemporary Phoenix — of a city threatened by its particular brand of local politics and economic domination, shaped by more than the usual quotient of prejudice, greed, class insularity, and devotion to raw power.
It is a truism that communities that do not pull together fail to surmount their challenges. Phoenix’s are as daunting as any faced by an American city in the new age of climate change, but its winner-take-all politics (out of which has come Arizona’s flagrantly repressive anti-immigration law), combined with the fragmentation of the metro-area into nearly two dozen competing jurisdictions, essentially guarantee that, when the worst of times hit, common action and shared sacrifice will remain as insubstantial as a desert mirage. When one day the U-Haul vans all point away from town and the people of the Valley of the Sun clog the interstates heading for greener, wetter pastures, more than the brutal heat of a new climate paradigm will be driving them away. The breakdown of cooperation and connectedness will spur them along, too.
One day, some of them may look back and think of the real estate crash of 2007-2008 and the recession that followed with fond nostalgia. The city’s economy was in the tank, growth had stalled, and for a while business-as-usual had nothing usual about it. But there was a rare kind of potential. That recession might have been the last best chance for Phoenix and other go-go Sunbelt cities to reassess their lamentably unsustainable habits and re-organize themselves, politically and economically, to get ready for life on the front burner of climate change. Land use, transportation, water policies, building codes, growth management — you name it — might all have experienced a healthy overhaul. It was a chance no one took. Instead, one or several decades from now, people will bet on a surer thing: they’ll take the road out of town.

Full Disk View Showing Earth on 4.13 - "Pi Day"

this is our shared responsibility!
our commons, our life support!

Tuesday, March 12, 2013

Water crisis calls for long-term plan, not constant cuts, says Alternative Federal Budget

[12-Mar-13] Water crisis calls for long-term plan, not constant cuts, says Alternative Federal Budget
“Most of southern Canada is losing its renewable water sources at an alarming rate, with communities facing low water levels and pollution from fracking, tar sands development, mining and other industrial projects. We are at a critical time to invest in protecting our communities’ water sources,” says Emma Lui, Water Campaigner for the Council of Canadians. “We not only need the scientific evidence from crucial programs like the ELA, but also legislation that will ensure clean water for current and future generations.”
The AFB also calls for the federal government to implement the human right to water and sanitation by allocating $2 million to reinstate the ELA, rolling back changes to environmental legislation and investing in water and wastewater infrastructure, a Great Lakes Action Plan and studies on the effects of tar sands development and fracking on water.
The AFB highlights the federal government’s two omnibudget bills, which severely weakened environmental legislation, and warns that: “The bills not only marked a troubling move that stifled democratic debate on environmental policy but also cast doubt on the government’s ability to uphold the human right to water and sanitation.”
The AFB also calls on the federal government to provide funding for water and wastewater infrastructure without requiring Public-Private Partnerships (P3s). Currently, several municipalities are considering applying to the P3 Canada Fund, which provides funding to municipalities only if they enter into an agreement with a private company. Case studies in Canada and around the world have show that P3s have resulted in price increases, job losses and decreases in water quality.

Thursday, March 7, 2013

Other People’s Money: How Crowdfunding Lowers the Cost of Solar Energy

Other People’s Money: How Crowdfunding Lowers the Cost of Solar Energy

In fact, about 75% of residential solar photovoltaic projects and 40% of commercial ones are financed with different “third-party ownership” models where electricity users install a solar system with little to no money down and start saving money from day one.
But the capital used to deploy these third-party-owned solar projects has an effective interest rate that looks more like that of a credit card than a mortgage. This translates into high monthly payments for electricity from solar systems—just like a homeowner making steep payments on a credit card in the home purchase example. Although it’s not the only factor at play, high interest rates (closely related to “costs of capital”) are one of the big reasons we only see lots of solar in places like Hawaii (where residents pay the highest electricity rates in the nation), but not Kentucky: Solar developers can only produce savings for customers in areas with a combination of high electricity rates, good sunlight, and attractive local incentives—think California and Arizona, two leading states nationwide for total installed solar capacity.
For folks interested in deploying as much solar in the U.S. as quickly as possible, this is a problem. Right now, the capital structure behind most solar projects in the U.S. is prohibitively expensive for the economics of solar to pencil out in most of the country. So, we’ve got to help make capital for solar projects look more like home mortgage loans than credit card debt.
There are a number of ways to do this, but many of the most popular solutions, such as master limited partnerships and solar-specific real estate investment trusts, require regulatory and/or federal legislative changes and aren’t likely to become large-scale solutions in the near term. However, there’s one solution that’s already upon us—crowdfunding.

Crowdfunding lowers costs

As shown in the animation, the “credit card-like” capital that’s currently used for solar projects is composed of expensive equity from two sources: tax equity investors (companies able to absorb the tax benefits associated with solar projects) and solar developers. This equity is expensive and, in simple terms, has an effective interest rate of over 15%. This translates into high a high cost of electricity from solar systems.
But this is where groups such as Mosaic step in. Expensive tax equity is still used to pay for about half of a project, but instead of using equity from the solar developer, crowdfunding providers can step in with funds from the crowd. Capital raised from the crowd has a much lower interest rate (~6.5%) than equity put in from a solar developer (~15%), so the combined interest rate for the solar project goes down, along with the cost of electricity from the solar system.
Finally, at some point in the future we could imagine crowdfunding companies providing all of the capital for a solar project. This would mean a very low interest rate on the entire project and a very low cost of electricity from the solar system.
There are a number of different solutions in development that will help lower interest rates associated with solar PV financing. But crowdfunding excites me for one main reason: it’s here now. And if we’re to get on pace to realize RMI’s vision of a secure, low-carbon, and affordable U.S. electricity system by 2050 as outlined in Reinventing Fire, we need solutions that drive deployment of existing technology as soon as possible.
This blog post originally appeared on Greenbiz.


Tuesday, March 5, 2013

The next revolution in Net Zero buildings: Occupants |

The next revolution in Net Zero buildings: Occupants |

Monday, March 4, 2013

RecycleBot v2.3 Controls by jpearce - Thingiverse

RecycleBot v2.3 Controls by jpearce - Thingiverse


A RecycleBot is a waste plastic extruder that creates 3-D printer filament from waste plastic and natural polymers.
This is a fully automated version of Recyclebot v2.2 with many improved features. For more info see C. Baechler, M. DeVuono, and J. M. Pearce, “Distributed Recycling of Waste Polymer into RepRap Feedstock” Rapid Prototyping Journal, 19(2), pp. 118-125 (2013).


The mechanical design is equivalent to RecycleBot v.2.2 - I strongly recommend reading that first. This design is, of course, far from optimized particularly with respect to cost and DYI, it is primarily being used by the Michigan Tech in Open Sustainability Technology Research Group to make new fucntionalized 3-D printing materials (e.g. electrically conductive) to support a full range of products open-source disributed manufacturing...lots more to come.

Some of the improved features over RecycleBot v2.2 are:
1. Type of plastic can be selected from the keypad interface and the controller automatically updates the extrusion temperature for the plastic.
2. Extrusion temperature can also be feed by the keypad interface for any type of plastic which can be melted and extruded.
3. LCD interface for better process monitoring.
4. No extrusion until the extrusion temperature is achieved - automatically controlled by microcontroller, with (manual option).
5. Low cost power control options using a Triac and MOSFET.

The energy performance of v2.2 can also be significantly improved with insulation.

Heating Zone
As the heater is the most important section it must be designed and fabricated precisely for better results as changes in temperature of few degrees can result in different mechanical properties of the extruded plastic. Another important criteria for the heating section is to create uniform heating environment so that the temperature remains nearly constant throughout the barrel such that the extruded plastic is uniform. To achieve this, high temperature ceramic beads were used to insulate the bare nichrome wire so as to achieve electrical isolation from the iron barrel, and an advantage of using this scheme is high-quality thermal insulation from the ambient environment and heat transfers efficiently to the iron barrel as the bottom side of the ceramic beads rest on the metal tightly and the top surface is insulated to the air, which is then insulated as well.

Steps to make the heater section

1. Clean the barrel and then make the top surface rough with a file.
2. Again clean the surface and remove any residing metal debris and dust.
3. Cut the required length of nichrome wire and straighten that up and hook the ends to a clamp.
4. Carefully insert the ceramic beads onto the nichrome wire one by one till the whole wire is completely covered up with ceramic beads.
5. Take the furnace cement and cover-up the iron barrel throughout the surface, it need to be made sure that whole surface is completely covered up with furnace cement as any exposed bare metal can posses the risk of short circuit with the bare nichrome and hence elevating the chances of electric shock (and destroying your power supply).
6. Gently take the nichrome wire and place it over the barrel and slowly cover up the barrel as if making a coil out of nichrome wire.
7. Fix the two free ends of the nichrome tightly to a clamp and apply furnace cement to cover up the whole surface of ceramic beads and it should look like the picture given in gallery. Again it is stressed that the furnace cement must be applied all over to cover the whole surface of ceramic beads so as to adhere strongly to the underlying metal and it should also make an electrical insulation layer such that bare nichrome shouldn't touch the metal anywhere.
8. Allow it to dry for at least 24 hours.
9. Connect the two free ends with alligator clips to power up the heater.

Safety note use gloves while using furnace cement as its alkaline in nature and can injure you and damage the skin if exposed for a prolonged time, if by chance skin comes in contact with furnace cement, then wash it under running water immediately. It is recommended that you do this in a hood if you have access to one.

Temperature Monitoring and Process Control

Controlling the temperature and other related processes of plastic recycling and extrusion in an efficient manner and simultaneously decreasing the cost is the key challenge for RecycleBot development especially for home applications. In order to promote the RecycleBot for open sustainability, the whole control system is designed to work on Arduino, which is a very popular open source microcontroller based application development platform. Being easy to use and program with excellent user community support, Arduino is a low cost rapid prototyping platform ideal to implement control system for RecycleBot. Arduino Mega was used to design and implement the system, having enough input/ output pins for interfacing LCD, keypad, and other components.

The whole process is divided into two parts: Input mode and Control mode

Input mode

The process starts with user input of either plastic selection or extrusion temperature. With the option of 10 different types of plastic, user can select the desired type of plastic to recycle and the program automatically loads the optimum temperature range for operation/ extrusion for that particular type of plastic. Alternatively, user can also feed the temperature of extrusion for any type of plastic which can be operated below 350C. After the extrusion temperature is set, program ask the user to confirm the temperature and once the temperature is set, the program steps into the control mode.

Saturday, March 2, 2013

Top Chinese Manufacturers Will Produce Solar Panels for 42 Cents per Watt in 2015 : Greentech Media

Top Chinese Manufacturers Will Produce Solar Panels for 42 Cents per Watt in 2015 : Greentech Media: ""once the Fed tax credit expires in 2016 solar will be in serious trouble" Perhaps not.  Right now solar is doing pretty well with an average installed price of $3.56/watt.  (GMT 3rd qtr 2012)  Take 30% off those prices and you've got $2.49/watt.   Germany, in 2012, was installing at an average price of $2/watt.  We trail Germany 2-3 years in price points. Before 2016 we should be installing at or below Germany's average $2/watt.  That's a half dollar less than our current subsidized average. "

'via Blog this'