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08. Heating and Cooling

Energy for Heating and Cooling

2014-04-13. A molecular approach to solar power.  Excerpt: It’s an obvious truism, but one that may soon be outdated: The problem with solar power is that sometimes the sun doesn’t shine. Now a team at MIT and Harvard University has come up with an ingenious workaround — a material that can absorb the sun’s heat and store that energy in chemical form, ready to be released again on demand. This solution is no solar-energy panacea: While it could produce electricity, it would be inefficient at doing so. But for applications where heat is the desired output — whether for heating buildings, cooking, or powering heat-based industrial processes — this could provide an opportunity for the expansion of solar power into new realms. ...Unlike fuels that are burned, this system uses material that can be continually reused. It produces no emissions and nothing gets consumed...The adoption of carbon nanotubes to increase materials’ energy storage density is “clever,”...the resulting increase in energy storage density “is surprising and remarkable.” “This result provides additional motivation for researchers to design more and better photochromic compounds and composite materials that optimize the storage of solar energy in chemical bonds,” Kanai says... http://newsoffice.mit.edu/2014/molecular-approach-to-solar-power. By David L. Chandle, MIT News Office.

2014-01-21. White, Green or Black Roofs? Berkeley Lab Report Compares Economic Payoffs.  Excerpt: Looking strictly at the economic costs and benefits of three different roof types—black, white and “green” (or vegetated)—Lawrence Berkeley National Laboratory (Berkeley Lab) researchers have found in a new study that white roofs are the most cost-effective over a 50-year time span. While the high installation cost of green roofs sets them back in economic terms, their environmental and amenity benefits may at least partially mitigate their financial burden. ...“We leave open the possibility that other factors may make green roofs more attractive or more beneficial options in certain scenarios,” said Mandel, a graduate student researcher at Berkeley Lab. “The relative costs and benefits do vary by circumstance.” However, unlike white roofs, green roofs do not offset climate change. White roofs are more reflective than green roofs, reflecting roughly three times more sunlight back into the atmosphere and therefore absorbing less sunlight at earth’s surface. By absorbing less sunlight than either green or black roofs, white roofs offset a portion of the warming effect from greenhouse gas emissions. ...black roofs pose a major health risk in cities that see high temperatures in the summer. “In Chicago’s July 1995 heat wave a major risk factor in mortality was living on the top floor of a building with a black roof,” Rosenfeld said.... http://newscenter.lbl.gov/news-releases/2014/01/21/white-green-or-black-roofs-berkeley-lab-report-compares-economic-payoffs/. Julie Chao, UC Berkeley News Center. 

2012-04-06. NASA's New Ultra-green Building | Relevant to GSS Energy Use chapter 6, 7, 8, and Climate Change chapter 9. Excerpt: MOFFETT FIELD, Calif. -- NASA's newest building also is one of the nation's greenest. Sustainability Base is a highly intelligent facility designed to anticipate and react to changes in sunlight, temperature, wind and occupancy. It is designed to achieve, and is presently under consideration for, the U.S. Green Building Council's Leadership in Energy and Environmental Design (LEED) Platinum status, which is the highest LEED rating. Meeting the White House challenge to lead by example, NASA has repurposed its technologies and incorporated them into the new building. Sustainability Base features a Bloom Energy Box, for example, that uses fuel cell technology in a clean electrical-chemical process to produce electricity. The facility also has a water recovery system, derived from one originally designed for the International Space Station, which reduces unnecessary consumption of potable water. Digital press kit of Sustainability Base: http://www.nasa.gov/centers/ames/events/2012/sustainability-base-presskit.html  Info about Sustainability Base: http://www.nasa.gov/externalflash/sustainability-base  Info about Ames' green technologies: http://www.nasa.gov/centers/ames/greenspace

2012 Feb 10.  Grad students design an 'EcoFridge' that uses 40 per cent less energy.  By Leslie Guevarra, GreenBiz.com.  Excerpt:  …Imagine an environmentally friendly household refrigerator that is affordable and helps break people's energy-wasting habits when they use the appliance.
That is what team of UC Berkeley grad students in engineering and industrial design students from the Universidad Nacional Autónoma de México envisioned when they were asked by appliance manufacturer Mabe to develop a cost competitive fridge that is kinder to the environment than others available to consumers in Mexico….
…The Cal students…made it their goal to achieve the greatest reduction possible in environmental impacts without upsetting consumers' perceptions of how a refrigerator should look or radically altering how people use it….

2011 Sep 6. Get the Light, Beat the Heat: Berkeley Lab Researchers Develop New Infrared Coating for Windows. by Aditi Risbud, Berkeley Lab News Center.  Excerpt: Researchers with the U.S. Department of Energy (DOE)’s Lawrence Berkeley National Laboratory (Berkeley Lab) have unveiled a semiconductor nanocrystal coating material capable of controlling heat from the sun while remaining transparent. Based on electrochromic materials, which use a jolt of electric charge to tint a clear window, this breakthrough technology is the first to selectively control the amount of near infrared radiation. This radiation, which leads to heating, passes through the film without affecting its visible transmittance. Such a dynamic system could add a critical energy-saving dimension to “smart window” coatings….

2010 August 12. Seeking to Cool Air Conditioning Costs. By David LaGesse, National Geographic News. Excerpt: The air-conditioning industry is starting to feel the heat… it's getting tougher to squeeze more efficiency from today's cooling technology, offering little relief anytime soon for consumers fuming from summer electric bills.
…For one, air-conditioning units don't get replaced as often as, say, light bulbs or even refrigerators. It takes longer for more efficient models to spread into homes or businesses. Researchers also struggle to make new cooling technology as cheaply as the refrigeration pioneered by Willis Carrier in the early 1900s.
…AC units built to U.S. national standards, for one, dehumidify the air—a waste of energy in the arid Southwestern states. The U.S. Congress a few years ago authorized new air conditioning (and heating) standards that will divide the country into North, South and Southwest regions.
… [The Western Cooling Efficiency Center at the University of California, Davis] is pursuing several technologies with particular promise in the Southwest. They include radiant cooling that pipes chilled water around a building or systems that use chilly nights to inexpensively produce ice that can help make a building comfortable during the day.
…Some of the most promising advances are in evaporative cooling, which uses water to draw heat from air just as perspiration cools a body. It's already used in "swamp coolers" that tend to be more popular in drier climates.
…An evaporative cooler developed at the National Renewable Energy Laboratory uses drying compounds, or desiccants, to pull moisture from the air.
…A "desiccant-enhanced" prototype at the lab needs less than half, and perhaps 90 percent less, of the energy of a conventional air conditioner. It could be in field trials in three years and on the market soon after, says Eric Kozubal at the renewable energy lab.

2010 Jan 28. White Roofs May Successfully Cool Cities. NASA Release 10-016. Excerpt: Painting the roofs of buildings white has the potential to significantly cool off cities and mitigate some impacts of global warming, results of a new study indicate.
The research, the first computer modeling study to simulate the impacts of white roofs on urban areas worldwide, suggests there may be merit to the idea of turning roofs white.
...Cities are particularly vulnerable to climate change because they are warmer than outlying rural areas.
Asphalt roads, tar roofs and other artificial surfaces absorb heat from the sun, creating an urban "heat island effect" that can raise temperatures on average by 2-5 degrees Fahrenheit (about 1-3 degrees Celsius) or more, compared to rural areas.
White roofs would reflect some of that heat back into space and cool temperatures, much as wearing a white shirt on a sunny day can be cooler than wearing a dark shirt.
...The model simulations, which provide scientists with an idealized view of different types of cities around the world, indicate that, if every roof were entirely painted white, the urban heat island effect could be reduced by 33 percent.
This would cool the world's cities by an average of about 0.7 F, with the cooling influence being particularly pronounced during the day, especially in summer.
The authors emphasize that their research should be viewed as a hypothetical look at typical city landscapes rather than the actual rooftops of any one city.
In the real world, the cooling impact might be somewhat less because dust and weathering would cause the white paint to darken over time and parts of roofs would remain unpainted because of openings such as heating and cooling vents....

2009 July 29. White Roofs Catch On as Energy Cost Cutters. By Felicity Barringer, The NY Times. Excerpt: ...Relying on the centuries-old principle that white objects absorb less heat than dark ones, homeowners...are in the vanguard of a movement embracing “cool roofs” as one of the most affordable weapons against climate change.
Studies show that white roofs reduce air-conditioning costs by 20 percent or more in hot, sunny weather. Lower energy consumption also means fewer of the carbon dioxide emissions that contribute to global warming.
What is more, a white roof can cost as little as 15 percent more than its dark counterpart, depending on the materials used, while slashing electricity bills.
Energy Secretary Steven Chu, a Nobel laureate in physics, has proselytized for cool roofs at home and abroad....
The scientist Mr. Chu calls his hero, Art Rosenfeld, a member of the California Energy Commission who has been campaigning for cool roofs since the 1980s, argues that turning all of the world’s roofs “light” over the next 20 years could save the equivalent of 24 billion metric tons in carbon dioxide emissions.
“That is what the whole world emitted last year,” Mr. Rosenfeld said. “So, in a sense, it’s like turning off the world for a year.”...

2009 May. Don't Toss Money out the Window. GreenTips - Union of Concerned Scientists. Windows let the sunshine in, but in many cases they also let the heat in (or out, in the winter). According to the Department of Energy, heat transfer through windows can account for 10 to 25 percent of your heating and air conditioning costs. Older, single-paned windows are the biggest energy wasters.
Replacing older windows with energy-efficient ones can be expensive, but will save you money in the long run by reducing your energy use as much as 30 percent. Energy Star-rated windows are twice as efficient as typical models sold just 10 years ago. A variety of factors determine a window's energy efficiency: *Solar heat*.... *Heat transfer*....*Glazing*....*Framing*.
...If you can't replace your old windows now, there are other steps you can take: *Seal air leaks*.... Affix *Low-E coated film* .... Install *storm windows*.... Use *insulating window treatments*.

2009 April 9. Prize for 'Sun in the box' cooker. By Richard Black, BBC News. Excerpt: A cheap solar cooker has won first prize in a contest for green ideas.
The Kyoto Box is made from cardboard and can be used for sterilising water or boiling or baking food.
The Kenyan-based inventor hopes it can make solar cooking widespread in the developing world, supplanting the use of wood which is driving deforestation.
Other finalists in the $75,000 competition included a device for streamlining lorries, and a ceiling tile that cools hot rooms.
Organised by Forum for the Future, the sustainable development charity founded by Jonathan Porritt, the competition aims to support concepts that have "moved off the drawing board and demonstrated their feasibility" for reducing greenhouse gas emissions, but have not gained corporate backing.
... It is made from two cardboard boxes, which use reflective foil and black paint to maximise absorption of solar energy.
Covering the cooking pot with a transparent cover retains heat and water, and temperatures inside the pot can reach at least 80C....
...Reducing reliance on firewood reduces deforestation, but also improves the health and wellbeing of villagers who do not have to trek for miles collecting the increasingly scarce wood nor spend hours inhaling wood smoke, a major cause of respiratory disease....

2008 December 26. Burning Coal At Home is Making A Comeback. By Tom Zeller Jr. and Stefan Milkowski. Excerpt: SUGARLOAF, Pa. — Kyle Buck heaved open the door of a makeshift bin abutting his suburban ranch house. Staring at a two-ton pile of coal that was delivered by truck a few weeks ago, Mr. Buck worried aloud that it would not be enough to last the winter...Aptly, perhaps, for an era of hard times, coal is making a comeback as a home heating fuel. Problematic in some ways and difficult to handle, coal is nonetheless a cheap, plentiful, mined-in-America source of heat. And with the cost of heating oil and natural gas increasingly prone to spikes, some homeowners in the Northeast, pockets of the Midwest and even Alaska are deciding coal is worth the trouble...Burning coal at home was once commonplace, of course, but the practice had been declining for decades. Coal consumption for residential use hit a low of 258,000 tons in 2006 — then started to rise. It jumped 9 percent in 2007, according to the Energy Information Administration, and 10 percent more in the first eight months of 2008...Coal may never make economic sense in areas far from where it is mined. But in places within reasonable delivery range, the price tends to be stable, compared with heating oil or natural gas. Prices for natural gas more than tripled in recent years before plunging in the last few months amid the downturn...

2008 December 26. No Furnaces but Heat Aplenty in ‘Passive Houses’. By Elizabeth Rosenthal. Excerpt: DARMSTADT, Germany — From the outside, there is nothing unusual about the stylish new gray and orange row houses in the Kranichstein District, with wreaths on the doors and Christmas lights twinkling through a freezing drizzle. But these houses are part of a revolution in building design: There are no drafts, no cold tile floors, no snuggling under blankets until the furnace kicks in. There is, in fact, no furnace...The concept of the passive house, pioneered in this city of 140,000 outside Frankfurt, approaches the challenge from a different angle. Using ultrathick insulation and complex doors and windows, the architect engineers a home encased in an airtight shell, so that barely any heat escapes and barely any cold seeps in. That means a passive house can be warmed not only by the sun, but also by the heat from appliances and even from occupants’ bodies...Decades ago, attempts at creating sealed solar-heated homes failed, because of stagnant air and mold. But new passive houses use an ingenious central ventilation system. The warm air going out passes side by side with clean, cold air coming in, exchanging heat with 90 percent efficiency...Inside, a passive home does have a slightly different gestalt from conventional houses, just as an electric car drives differently from its gas-using cousin. There is a kind of spaceship-like uniformity of air and temperature. The air from outside all goes through HEPA filters before entering the rooms. The cement floor of the basement isn’t cold. The walls and the air are basically the same temperature...

2008 August 26. Serving Architects, Consultants in Everything Green Become Mainstays. By LISA CHAMBERLAIN, The New York Times. Excerpt: On a recent Friday, when the rest of the staff of the architecture firm Beyer Blinder Belle was out of the office enjoying a beautiful August day, about 25 people sat in a windowless room learning about the Leadership in Energy and Environmental Design (LEED) certification process.
Conducting the seminar was Lauren Yarmuth of YRG Sustainable Consultants, one of a growing cadre of consultants who specialize in helping developers, architects and sometimes tenants gain an official stamp of approval from the United States Green Building Council through its LEED certification program — the undisputed calling card of environmental bragging rights.
...“Going green used to be part of just a handful of organizations’ mission statements, but now it’s become part of everyone’s agenda,” said Ashley Katz, communications director for the Green Building Council. “That has, of course, increased the need for sustainability consultants.”
Many of the consultants are, like Ms. Yarmuth, trained as architects and work directly with the Green Building Council to develop and refine the guidelines they help clients follow. At the end of 2006, the Green Building Council’s membership included 679 consultants. By July 31 this year, there were 1,590.
...Despite a seemingly straightforward point system and scorecard, getting LEED certification is not always easy. Even large firms with employees with titles like “environmental strategist” hire consultants to walk them through the process.
A year ago in May, CB Richard Ellis developed a corporate policy to be carbon neutral by 2010, according to Sally R. Wilson, global director of environmental strategy for the real estate investment and management firm....
...Ms. Wilson brought in Holley Henderson, a principal of H2 Ecodesign, based in Atlanta, to manage the process and make sure the architect was designing to LEED standards.
“Certified wood is a hot topic right now” with the Green Building Council, Ms. Henderson said by way of example. “The requirement is, 50 percent of wood has to be sustainably harvested. But keep in mind, if you use wheat or sunflower board or some other alternative, those are grasses, not wood. The way the credit reads, 50 percent is a lot, so the more you reduce your wood, the easier it is to get this credit. People who just look at the scorecard and checklist wouldn’t understand these nuances.”
...According to Thomas W. Hicks, vice president for international programs at the council, there are LEED projects under way in 75 countries. “There is tremendous demand to bring LEED in and localize it to their conditions,” Mr. Hicks said.

2008 July. Energy efficiency in the built environment. By Leon R. Glicksman, Physics Today. Excerpt: ...buildings are the largest energy consumer in the US, which is a surprise to many people. The combined residential and commercial building sectors consume close to 40% of the total primary US energy... The combined residential and commercial building sector also uses 70% of US electricity...
Given the enormous energy consumption by the building sector, a viable part of a CO2 control strategy should include increased energy efficiency for that sector...
Achieving substantial levels of energy efficiency requires a combination of technologies. If there is something approaching a silver bullet, it is integrated design—architects, developers, engineers, and energy consultants working together from conceptual design to finished construction...
Space heating constitutes the largest energy use in residential buildings. Active or passive solar-energy systems can meet a majority of the heating needs in most climates. Such systems require windows or solar thermal collectors—which collect the Sun's energy for heating purposes—oriented to receive a maximum of solar irradiation in the winter...
For commercial buildings, lighting represents the largest primary energy consumption. Higher-efficiency lighting has seen continued progress through compact fluorescent bulbs, higher-efficiency commercial fluorescent tubes and ballasts, and solid-state LEDs. Effective use of daylight combined with dimmers and occupancy sensors that eliminate unneeded artificial light can reduce energy use for lighting by more than 50%...
Energy for cooling both commercial and residential buildings is becoming a larger portion of the energy demand as the US population in southern regions continues to increase...
Shading and spectrally selective glazing can reduce solar heating of building interiors. Highly reflecting roofs, so-called cool roofs, can also reduce heat transfer to interiors; that approach is especially useful for single-story buildings with flat roofs. And novel integration of heat pumps and air conditioners in the buildings can meet the remaining cooling loads while yielding an overall energy savings...
Natural ventilation can reduce the seasonal energy requirements for cooling commercial buildings by 50% or more in many US and European climates...

2007 November 6. Massachusetts Looks at Using Biofuel in Home Heating Oil. By KATIE ZEZIMA. Excerpt: BOSTON, Nov. 5 - Gov. Deval L. Patrick and legislative leaders proposed a bill on Monday to require all home heating oil and diesel fuel to contain at least 5 percent biofuel by 2013.
Massachusetts would be the first state to require that home heating oil contain renewable fuels, a significant issue in a state where 36 percent of homes use home heating oil, according to Census figures. That compares with the 8 percent national average.
Maine leads the nation, with 87 percent of its homes using heating oil, according to the Census.
The bill would require that all home heating oil and diesel fuel contain 2 percent renewable fuel alternatives by 2010 and increase to 5 percent by 2013.
...Brooke Coleman of the Northeast Biofuels Collaborative said the savings would be modest.
"The biodiesel mandate will only have a small positive effect on fuel prices," Mr. Coleman said. "On the biodiesel side, the short-term price impact is going to be small. But the overarching goal here is to provide a foothold for biodiesel providers in the state, which will stabilize oil and diesel prices."...

2007 October. GREENTIPS - A Tip to Warm Your Hearth. Excerpt: With fall in the air, it's time to ensure your home is properly insulated. Insulation prevents heat from leaking out of your home in winter and into your home in summer, making it more comfortable year-round and reducing your energy consumption, global warming pollution, and heating and air conditioning costs.
The many options on the market today include fiberglass rolls, spray foam, rigid foam, and loose-fill cellulose made from old newspapers. To determine the best fit for your needs, consider these factors:
R-value. This number represents an insulation's ability to resist heat; the higher the R-value, the more effective the insulation....
Target spaces. Attics and cathedral ceilings are great places to start to get the most bang for your insulation bucks. Next in line should be walls, floors, crawl spaces, and basements.
Raw materials. Insulation made from non-petroleum resources, with a high recycled content, requires less energy to process, reduces waste, and uses fewer natural resources. ....
Installation. Foam insulation has traditionally been sprayed onto walls using chlorofluorocarbons (CFCs) or hydrochlorofluorocarbons (HCFCs)-chlorine-based chemicals that deplete the ozone layer. But it is now possible to apply foam insulation using chlorine-free agents such as hydrofluorocarbons (HFCs), carbon dioxide (CO2), and even water....
Disposal. In addition to choosing insulation with a high recycled content, consider whether it can be recycled at the end of its useful life....

2007 July 11. Hot off the grid/Solar ovens utilize nature's rays for energy-efficient, everyday cooking -- even in foggy San Francisco, Tara Duggan, SF Chronicle Staff Writer, Excerpt: ... 'I have to have one of those sun ovens,' says Sharon South, who recently moved from San Jose to Tuolumne County. "Because in the summer, who wants to turn the oven on?" This spring, South started using her solar oven about three times a week and plans to buy a second one so she and her husband can cook more dishes at once when they have guests. Solar cookers like the Sun Oven can maintain temperatures of 350 degrees or higher and start around $230. Less-insulated and simpler versions such as one called the CooKit cost about $32 and cook food in the low to mid 200 degrees -- hot enough to boil water, which is all you need for most cooking. ...The Sun Oven ... consists of a well-insulated box with a glass lid and four reflective panels that direct sunlight into the box. ... Solar cooking typically takes two to three times as long as conventional cooking. But once you get used to the relaxed rhythm, it can be easy and convenient, kind of like using a Crock-Pot. ... We found it perfect for low-and-slow cooking, such as a whole-grain rice pilaf....
Over 2 billion people, a third of the world's population, rely on wood-fueled fires to cook food. Of these people, around 500 million frequently encounter fuel shortages yet live in ideal climates for solar cooking, says Kevin Porter of Solar Cookers International (SCI) in Sacramento. Many women, especially refugees, trek miles to obtain cooking fuel, and the reliance on wood for fuel has led to deforestation in many areas. SCI and other organizations help impoverished communities gain access to solar ovens to cook food, pasteurize water and sterilize medical equipment. Since 1995, SCI has taught 30,000 families in eastern and southern Africa how to use solar ovens and has helped establish solar businesses in refugee communities. [Article also has:] Where to find solar ovens [and recipes:]
Baby Beet Salad with Feta, Walnuts & Arugula
Buttermilk Cornbread
Peach & Blackberry Cobbler
Rice Pilaf
Wheatless Apricot Cake
Shrimp & Lemon Skewers


 

Solar Cookers International (SCI) - Establishes programs in countries around the world to teach people to make and use solar ovens and cookers. Reduces deforestation and saves time for cultures that normally would gather wood for cooking fires. Reduces carbon dioxide (greenhouse gas) emission in cultures that normally use natural gas or electricity for cooking. See SCI Newsletters


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