#1 SPAS BIJELIH KROVOVA?
Posted: 18/06/2009 20:05
Obama's climate guru: Paint your roof white!
By Steve Connor, Science Editor
Wednesday, 27 May 2009
Houses with white roofs, like these in Greece, would be able to reflect light back through the atmosphere, according to Steven Chu, the US Secretary of Energy
Houses with white roofs, like these in Greece, would be able to reflect light back through the atmosphere, according to Steven Chu, the US Secretary of Energy
Some people believe that nuclear power is the answer to climate change, others have proposed green technologies such as wind or solar power, but Barack Obama's top man on global warming has suggested something far simpler – painting your roof white.
Steven Chu, the US Secretary of Energy and a Nobel prize-winning scientist, said yesterday that making roofs and pavements white or light-coloured would help to reduce global warming by both conserving energy and reflecting sunlight back into space. It would, he said, be the equivalent of taking all the cars in the world off the road for 11 years.
Speaking in London prior to a meeting of some of the world's best minds on how to combat climate change, Dr Chu said the simple act of painting roofs white could have a dramatic impact on the amount of energy used to keep buildings comfortable, as well as directly offsetting global warming by increasing the reflectivity of the Earth.
"If that building is air-conditioned, it's going to be a lot cooler, it can use 10 or 15 per cent less electricity," he said. "You also do something in that you change the albedo of the Earth – you make it more reflective. So the sunlight comes down and it actually goes back up – there is no greenhouse effect," Dr Chu said.
When sunlight is reflected off a white or light-coloured surface much of that light will pass through the atmosphere and back into space, unlike the infrared radiation emitted from the Earth's warmed-up surface, which is blocked by greenhouse gases and causes global warming. "What we're doing is that, as we put in more greenhouse gases, we're putting in more insulation for infrared light. So if you make white roofs and the sunlight comes in, it goes right through that [insulation]," said Dr Chu.
The principle could also be extended to cars where white or "cool colours" designed to reflect light and radiation could make vehicles more energy efficient in summer. "If all vehicles were light-coloured, there could be considerable savings because then you can downsize the air conditioning... and downsizing the air conditioner means more efficient air conditioning and a considerable reduction in energy," he said.
Asked about whether the US administration has any plans to manipulate the climate artificially using large-scale geoengineering programmes, Dr Chu said there were no such plans "at this time". But painting surfaces white is one geoengineering proposal that he is taking seriously.
"Now you smile, but if you look at all the buildings and make all the roofs white, and if you make the pavement a more concrete-type of colour than a black-type of colour, and you do this uniformly... It's the equivalent of reducing the carbon emissions due to all the cars in the world by 11 years," he said.
"It's like you've just taken them off the road for 11 years. It's actually geoengineering."
The idea would even work in countries with temperate climates, such as Britain, because white-coloured roofs would help to reflect the radiated heat from homes and offices back into the building during winter months, said Dr Chu. One unresolved issue concerns the aesthetic considerations of making sloping roofs white. But with flat roofs that are not visible from the street, there should be no objection to painting them white, he said
Dr Chu is one of 20 Nobel prize-winning scientists attending a meeting on climate change at the Royal Society and St James's Palace organised by Cambridge University. He said energy efficiency will be the most immediate way of reducing emissions of greenhouse gases.
The white revolution: How it would work
* The idea of painting surfaces white to conserve energy is being actively pursued by the US. Earlier this month, Barack Obama's chief scientific adviser, John Holdren, received a scientific memorandum on the subject.
* Scientists estimate that making roofs and pavements white or more light-coloured would counter global warming with "negative radiative forcing" – reflecting sunlight back into space. They said that retrofitting urban roofs and pavements in tropical and temperate regions with solar-reflective materials would offset about 44 billion tonnes of carbon dioxide.
* The scientists said it would lower the cost of air conditioning, making buildings more comfortable and mitigate the "urban heat island" effect caused by the concentration of concrete surfaces in cities.
Houses with white roofs, like these in Greece, would be able to reflect light back through the atmosphere, according to Steven Chu, the US Secretary of Energy
preuzeto sa http://www.independent.co.uk
---------------------------------------------------------------------------------------------------------------------------------------------------
Spasonosni ravni bijeli krov
Ako bi svi ravni krovovi bili obojeni u bijelo, klima-uređaji ne bi toliko crpili energiju i smanjili bi emisiju štetnih plinova kao nakon 11 godina bez automobila. A kad bismo posvijetlili automobile...
Američki ministar za energiju, nobelovac Steven Chu želi da što više Amerikanaca oboji svoje krovove u bijelu boju. Objavio je to na klimatskom simpoziju u Londonu.
Poznati fizičar, danas član Obamine administracije, poziva na "novu revoluciju" u generiranju energije i smanjivanju emisije stakleničkih plinova. Ipak upozorava kako ne postoji univerzalni lijek koji će jednim potezom ukloniti klimatske promjene, te naglašava potrebu za cijelim nizom dobro promišljenih mjera, uključujući i bojanje ravnih krovova bijelom bojom.
Posvijetljenje cesta i krovova može imati isto djelovanje kao uklanjanje svih automobila na 11 godina, rekao je Chu.
Ovo je vrlo jednostavna benigna metoda koja će omogućiti da zgrade budu hladnije i smanjiti potrebu za klima uređajima i istovremeno reflektirati svjetlost od Zemlje.
Za ljude kojima bi bijelo bilo estetski neprihvatljivo izumili su "cool boje" koje ljudskom oku izgledaju poput normalnih no čak i kad su tamnijih nijansi reflektiraju svjetlost kao i blijede boje.
Bojenje automobila u svjetlije boje također bi značajno uštedjelo energiju koja se sad rasipa na rashlađivanje.
Govoreći na početku simpozija posvećenom klimatskim promjenama kojom predsjedava britanski princ Charles, u društvu još 20 drugih nobelovaca Chu je rekao da je presudno unijeti svježe razmišljanje. "Industrijska revolucija bila je revolucionarna po pitanju korištenja energije jer smo s ljudske i životinjske snage prešli na iskorištavanje fosilnih goriva."
"Sad trebamo jednu drugačiju revoluciju koja će značajno smanjiti emisiju ugljika," zaključio je.
Izvor: Net.hr
preuzeto sa gromobol.com
--------------------------------------------------------------------------------------------------------------------------------------
Antonije Pušić (Rambo Amadeus) je ofarbao krovnu ploču porodične kuće u Herceg Novom u bijelu boju, koja se koristi za farbanje pješačkih prelaza, i time postigao da se kuća hladi sama od sebe, skupljajući hladnoću iz zemlje, preko temelja i zidova.
Na spoljinh 40 stepeni u kući je prijatnih 28, a uveče je potrebno i pokriti se nekom dekicom. Zahvaljujemo svima koji su se javili sa pitanjima, odgovorićemo na ovom mjestu.
Pitanja u vezi bijelog krova
1. Da li vrijedi ofarbati crep u bijelo i kako?
Naravno da vrijedi, crep farbati sa razrijedjenim krečom, nekoliko puta, jer puno upija boju, ali na kraju ipak postane bijel.
2. krov je svijetlo siv, mora li da se farba?
Naravno, i svijetlo siva privlači previše sunca, samo potpuno bijela boja daje zadovoljavajući učinak.
3. Krov mi je od lima, koji se preko dana usijava, hoće li pomoći bijela boja?
Naravno. Nakon farbanja se više neće usijavati.
4. Mora li neka specijalna boja?
Ne. Važno je da je bijela, i da je postojana na atmosferske prilike. I naravno, da dobro pokriva, zato sam ja izabrao "Asfalton".
5. Moraju li i zidovi koji su okrenuti suncu da se farbaju u bijelo ili je dovoljno ofarbati samo krov?
Naravno da mora. Svaka površina izložena suncu mora da se ofarba u bijelo, ako želite zaista dobar učinak.
6. kako ste otkrili ovaj fenomen?
7. Prekopirao sam hiljadugodišnje iskustvo sunčanog bliskog istoka i afričkog mediterana. Nama sada grije kao njima dok je bilo sve normalno.
preuzeto sa ramboamadeus.com
------------------------------------------------------------------------------------------------------------------------------------------------
Reflective White Roofs Cut Energy Costs 20%
A study released September 9, 2008 by scientists from Lawrence Berkeley National Laboratory in California quantified what traditional builders have known for centuries: that white roofs help deflect the sun’s hot rays and reduce the indoor temperature of the building below. In air-conditioned houses, a reflective white roof helps reduce the amount of heat that reaches the inside of the house, reducing the need for air conditioning. In houses without air conditioning, a white roof keeps the house more comfortable on hot days.
Potential Savings: 20% of Your Home’s Annual Energy Use
"White roofs can cut a building's energy use by 20% and save consumers money," says California Energy Commissioner Art Rosenfeld. "The potential energy savings in the U.S. is in excess of $1 billion annually.”
While cool roofs significantly reduce a building’s cooling load in most climate zones around the world, they can also increase heating costs in winter months by reflecting solar heat back into the air instead of absorbing it as other roofs do. But the energy savings in warm months typically greatly outweigh the extra costs in winter, since less of the sun’s heat reaches the earth in winter.
Dramatic Reductions in Greenhouse Gas Emissions
The reduction in electricity use has the added benefit of reducing power plant carbon dioxide emissions. The study estimates that replacing nonreflective, dark roofing materials with a white roof on an average house with a 1,000-square-foot roof would reduce CO2 (carbon dioxide) emissions by 10 metric tons a year.
Reducing the Risk of Blackouts and Brownouts
Energy managers dread the hot, sunny days when millions of air conditioners click on at the same time, straining the power grid and sometimes even causing brownouts or blackouts. Air conditioning demand peaks from mid-afternoon to early evening on hot days, when the sun beats down hardest on air-conditioned houses. White roofs help lighten the strain on the grid by reflecting more of the sun’s energy back into space at just the moment when conservation is most needed.
Choosing an Energy-Efficient Roof
If it’s time to replace your roof, industry experts recommend looking at four types of energy-efficient roofing materials:
1. Metal roofs. These perform best with a factory-applied polymeric coating that helps the metal radiate the heat away more quickly.
2. Ceramic or concrete roofing tile
3. Roofing membranes
4. White reflective coatings
(Naravno ovdje dolazi i u obzir bijela asfaltna boja koja se koristi za pjesacke prelaze, kojom se efektno moze obojiti krovna povrsina i fasada)
Check with a professional roofer to see which material fits best with your house. The energy and money savings definitely make it worth the effort to seek out energy-efficient roofing.
Read more: http://saving-energy.suite101.com/artic ... IqFcARP2&C
By Steve Connor, Science Editor
Wednesday, 27 May 2009
Houses with white roofs, like these in Greece, would be able to reflect light back through the atmosphere, according to Steven Chu, the US Secretary of Energy
Houses with white roofs, like these in Greece, would be able to reflect light back through the atmosphere, according to Steven Chu, the US Secretary of Energy
Some people believe that nuclear power is the answer to climate change, others have proposed green technologies such as wind or solar power, but Barack Obama's top man on global warming has suggested something far simpler – painting your roof white.
Steven Chu, the US Secretary of Energy and a Nobel prize-winning scientist, said yesterday that making roofs and pavements white or light-coloured would help to reduce global warming by both conserving energy and reflecting sunlight back into space. It would, he said, be the equivalent of taking all the cars in the world off the road for 11 years.
Speaking in London prior to a meeting of some of the world's best minds on how to combat climate change, Dr Chu said the simple act of painting roofs white could have a dramatic impact on the amount of energy used to keep buildings comfortable, as well as directly offsetting global warming by increasing the reflectivity of the Earth.
"If that building is air-conditioned, it's going to be a lot cooler, it can use 10 or 15 per cent less electricity," he said. "You also do something in that you change the albedo of the Earth – you make it more reflective. So the sunlight comes down and it actually goes back up – there is no greenhouse effect," Dr Chu said.
When sunlight is reflected off a white or light-coloured surface much of that light will pass through the atmosphere and back into space, unlike the infrared radiation emitted from the Earth's warmed-up surface, which is blocked by greenhouse gases and causes global warming. "What we're doing is that, as we put in more greenhouse gases, we're putting in more insulation for infrared light. So if you make white roofs and the sunlight comes in, it goes right through that [insulation]," said Dr Chu.
The principle could also be extended to cars where white or "cool colours" designed to reflect light and radiation could make vehicles more energy efficient in summer. "If all vehicles were light-coloured, there could be considerable savings because then you can downsize the air conditioning... and downsizing the air conditioner means more efficient air conditioning and a considerable reduction in energy," he said.
Asked about whether the US administration has any plans to manipulate the climate artificially using large-scale geoengineering programmes, Dr Chu said there were no such plans "at this time". But painting surfaces white is one geoengineering proposal that he is taking seriously.
"Now you smile, but if you look at all the buildings and make all the roofs white, and if you make the pavement a more concrete-type of colour than a black-type of colour, and you do this uniformly... It's the equivalent of reducing the carbon emissions due to all the cars in the world by 11 years," he said.
"It's like you've just taken them off the road for 11 years. It's actually geoengineering."
The idea would even work in countries with temperate climates, such as Britain, because white-coloured roofs would help to reflect the radiated heat from homes and offices back into the building during winter months, said Dr Chu. One unresolved issue concerns the aesthetic considerations of making sloping roofs white. But with flat roofs that are not visible from the street, there should be no objection to painting them white, he said
Dr Chu is one of 20 Nobel prize-winning scientists attending a meeting on climate change at the Royal Society and St James's Palace organised by Cambridge University. He said energy efficiency will be the most immediate way of reducing emissions of greenhouse gases.
The white revolution: How it would work
* The idea of painting surfaces white to conserve energy is being actively pursued by the US. Earlier this month, Barack Obama's chief scientific adviser, John Holdren, received a scientific memorandum on the subject.
* Scientists estimate that making roofs and pavements white or more light-coloured would counter global warming with "negative radiative forcing" – reflecting sunlight back into space. They said that retrofitting urban roofs and pavements in tropical and temperate regions with solar-reflective materials would offset about 44 billion tonnes of carbon dioxide.
* The scientists said it would lower the cost of air conditioning, making buildings more comfortable and mitigate the "urban heat island" effect caused by the concentration of concrete surfaces in cities.
Houses with white roofs, like these in Greece, would be able to reflect light back through the atmosphere, according to Steven Chu, the US Secretary of Energy
preuzeto sa http://www.independent.co.uk
---------------------------------------------------------------------------------------------------------------------------------------------------
Spasonosni ravni bijeli krov
Ako bi svi ravni krovovi bili obojeni u bijelo, klima-uređaji ne bi toliko crpili energiju i smanjili bi emisiju štetnih plinova kao nakon 11 godina bez automobila. A kad bismo posvijetlili automobile...
Američki ministar za energiju, nobelovac Steven Chu želi da što više Amerikanaca oboji svoje krovove u bijelu boju. Objavio je to na klimatskom simpoziju u Londonu.
Poznati fizičar, danas član Obamine administracije, poziva na "novu revoluciju" u generiranju energije i smanjivanju emisije stakleničkih plinova. Ipak upozorava kako ne postoji univerzalni lijek koji će jednim potezom ukloniti klimatske promjene, te naglašava potrebu za cijelim nizom dobro promišljenih mjera, uključujući i bojanje ravnih krovova bijelom bojom.
Posvijetljenje cesta i krovova može imati isto djelovanje kao uklanjanje svih automobila na 11 godina, rekao je Chu.
Ovo je vrlo jednostavna benigna metoda koja će omogućiti da zgrade budu hladnije i smanjiti potrebu za klima uređajima i istovremeno reflektirati svjetlost od Zemlje.
Za ljude kojima bi bijelo bilo estetski neprihvatljivo izumili su "cool boje" koje ljudskom oku izgledaju poput normalnih no čak i kad su tamnijih nijansi reflektiraju svjetlost kao i blijede boje.
Bojenje automobila u svjetlije boje također bi značajno uštedjelo energiju koja se sad rasipa na rashlađivanje.
Govoreći na početku simpozija posvećenom klimatskim promjenama kojom predsjedava britanski princ Charles, u društvu još 20 drugih nobelovaca Chu je rekao da je presudno unijeti svježe razmišljanje. "Industrijska revolucija bila je revolucionarna po pitanju korištenja energije jer smo s ljudske i životinjske snage prešli na iskorištavanje fosilnih goriva."
"Sad trebamo jednu drugačiju revoluciju koja će značajno smanjiti emisiju ugljika," zaključio je.
Izvor: Net.hr
preuzeto sa gromobol.com
--------------------------------------------------------------------------------------------------------------------------------------
Antonije Pušić (Rambo Amadeus) je ofarbao krovnu ploču porodične kuće u Herceg Novom u bijelu boju, koja se koristi za farbanje pješačkih prelaza, i time postigao da se kuća hladi sama od sebe, skupljajući hladnoću iz zemlje, preko temelja i zidova.
Na spoljinh 40 stepeni u kući je prijatnih 28, a uveče je potrebno i pokriti se nekom dekicom. Zahvaljujemo svima koji su se javili sa pitanjima, odgovorićemo na ovom mjestu.
Pitanja u vezi bijelog krova
1. Da li vrijedi ofarbati crep u bijelo i kako?
Naravno da vrijedi, crep farbati sa razrijedjenim krečom, nekoliko puta, jer puno upija boju, ali na kraju ipak postane bijel.
2. krov je svijetlo siv, mora li da se farba?
Naravno, i svijetlo siva privlači previše sunca, samo potpuno bijela boja daje zadovoljavajući učinak.
3. Krov mi je od lima, koji se preko dana usijava, hoće li pomoći bijela boja?
Naravno. Nakon farbanja se više neće usijavati.
4. Mora li neka specijalna boja?
Ne. Važno je da je bijela, i da je postojana na atmosferske prilike. I naravno, da dobro pokriva, zato sam ja izabrao "Asfalton".
5. Moraju li i zidovi koji su okrenuti suncu da se farbaju u bijelo ili je dovoljno ofarbati samo krov?
Naravno da mora. Svaka površina izložena suncu mora da se ofarba u bijelo, ako želite zaista dobar učinak.
6. kako ste otkrili ovaj fenomen?
7. Prekopirao sam hiljadugodišnje iskustvo sunčanog bliskog istoka i afričkog mediterana. Nama sada grije kao njima dok je bilo sve normalno.
preuzeto sa ramboamadeus.com
------------------------------------------------------------------------------------------------------------------------------------------------
Reflective White Roofs Cut Energy Costs 20%
A study released September 9, 2008 by scientists from Lawrence Berkeley National Laboratory in California quantified what traditional builders have known for centuries: that white roofs help deflect the sun’s hot rays and reduce the indoor temperature of the building below. In air-conditioned houses, a reflective white roof helps reduce the amount of heat that reaches the inside of the house, reducing the need for air conditioning. In houses without air conditioning, a white roof keeps the house more comfortable on hot days.
Potential Savings: 20% of Your Home’s Annual Energy Use
"White roofs can cut a building's energy use by 20% and save consumers money," says California Energy Commissioner Art Rosenfeld. "The potential energy savings in the U.S. is in excess of $1 billion annually.”
While cool roofs significantly reduce a building’s cooling load in most climate zones around the world, they can also increase heating costs in winter months by reflecting solar heat back into the air instead of absorbing it as other roofs do. But the energy savings in warm months typically greatly outweigh the extra costs in winter, since less of the sun’s heat reaches the earth in winter.
Dramatic Reductions in Greenhouse Gas Emissions
The reduction in electricity use has the added benefit of reducing power plant carbon dioxide emissions. The study estimates that replacing nonreflective, dark roofing materials with a white roof on an average house with a 1,000-square-foot roof would reduce CO2 (carbon dioxide) emissions by 10 metric tons a year.
Reducing the Risk of Blackouts and Brownouts
Energy managers dread the hot, sunny days when millions of air conditioners click on at the same time, straining the power grid and sometimes even causing brownouts or blackouts. Air conditioning demand peaks from mid-afternoon to early evening on hot days, when the sun beats down hardest on air-conditioned houses. White roofs help lighten the strain on the grid by reflecting more of the sun’s energy back into space at just the moment when conservation is most needed.
Choosing an Energy-Efficient Roof
If it’s time to replace your roof, industry experts recommend looking at four types of energy-efficient roofing materials:
1. Metal roofs. These perform best with a factory-applied polymeric coating that helps the metal radiate the heat away more quickly.
2. Ceramic or concrete roofing tile
3. Roofing membranes
4. White reflective coatings
(Naravno ovdje dolazi i u obzir bijela asfaltna boja koja se koristi za pjesacke prelaze, kojom se efektno moze obojiti krovna povrsina i fasada)
Check with a professional roofer to see which material fits best with your house. The energy and money savings definitely make it worth the effort to seek out energy-efficient roofing.
Read more: http://saving-energy.suite101.com/artic ... IqFcARP2&C