Posts tagged ‘Photovoltanic cell’

July 19, 2011

Solar panels roof could cool you home

by Jasmina Nikoloska

The journal Solar Energy recently published a study that shows additional benefits of having a solar panel roof.

According to a team of researchers led by Jan Kleissl, a professor of environmental engineering at the UC San Diego Jacobs School of Engineering, a solar photovoltaic panels not only provide clean power, they are cooling too.

Measurements of the thermal conditions throughout a roof on a building partially covered by solar photovoltaic (PV) panels were conducted in San Diego in April, and thermal infrared imagery on a clear demonstrated that daytime ceiling temperatures under the PV arrays were up to 2.5 K cooler than under the exposed roof.

Heat flux modelling showed a significant reduction in daytime roof heat flux under the PV array. At night the conditions reversed and the ceiling under the PV arrays was warmer than for the exposed roof indicating insulating properties of PV.

Simulations showed a 38 percent reduction in annual cooling load.

The team believes that much of the heat is removed by wind blowing between the panels and the roof and the benefits could be larger if there is an opening where air can circulate between the building and the solar panel, therefore tilted panels will provide more cooling.

Also, the more efficient the solar panels, the bigger the cooling effect, said Kleissl.

Since the use solar panels are growing it is important to know about their positive side effects and their impact on buildings’ total energy costs, according to Kleissl.

Although he thinks that there are more efficient ways to passively cool buildings, such as reflective roof membranes, he believes that depending on roof thermal properties installing PVs could increase reduction in the amount of used energy to cool your residence or business.

It was estimated that savings in cooling costs amounted to selling 5 percent more solar energy to the grid than the panels are actually producing.




February 5, 2011

Solar industry raises concerns of potential e-waste

by Jasmina Nikoloska

Reducing the use of fossil fuel, cutting greenhouse gases and other air pollution emissions have become recognised necessities; the recent explosive growth of solar technology is a welcomed occurrence because of the expected energy crisis.

Thankfully, the Sun is most widely available energy resource.

However, solar modules contain some of the potentially dangerous substances found in electronic waste, including silicon tetrachloride, cadmium, selenium and sulphur hexafluoride, which is a potent greenhouse gas.

The US Environmental Protection Agency (EPA) estimates that e-waste is growing at two to three times the rate of any other source of waste; furthermore, only 15 to 20 per cent of e-waste is recycled.

The crystalline photovoltaic cell is the oldest and most widespread solar technology in the United States, holding a 57 per cent market share in 2009, according to Greentech Media. A thin film technology called cadmium telluride holds about 21 per cent, while copper indium gallium selenide (CIGS) currently has a market share of just 6 per cent. Amorphous silicon, which also has an indium tin oxide layer, takes 16 per cent.

Silicon Valley Toxic Coalition (SCTC) issued a report in 2009 warning that solar panels provide clean energy while in use, but a variety of factors during their manufacturing and disposal has the potential to greatly damage the environment.

Now is the right time to recognise the necessary measures for the solar industry to remain sustainable and retain it green credibility. Although solar panels have a life expectancy of approximately 25 years, and it is not expected for large amounts of modules to be returned for another 10 to 15 years for recycling or disposal, there is a big e-waste potential.

It is important to build proper infrastructure and address the issues of producer responsibility, recycling in an attempt to avoid the danger of electronic waste and future plans for the disposal of solar panels that are no longer needed.

Still, most companies that are beginning recycling programmes today are proceeding under the assumption that recycling will be costly. They are preparing for that expense by creating a variety of funding mechanisms based on the principle of producer responsibility, The Guardian wrote on 3 September 2010.

Currently there is nothing much to recycle except…..

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