Tuesday, December 29, 2009

White roofs and computers to combat climate change

I will be interviewed on Eastside 87.9 FM Radio in Sydney at 4pm Wednesday about how to save energy to combat climate change. This was promoted by a media report that the the Lord Mayor of Melbourne, Robert Doyle, has proposed roofs of inner city buildings be painted white to make them cooler. According to ABC TV's Green Guru, this is plausible. However, before doing this I would suggest looking at insulating the roof. The Australian Government's Home Insulation Program provides up to $1,200 ceiling insulation in homes. But hopefully we will get around to talking about how computers and telecommunications can be used to reduce energy. In the case of high rise inner city buildings, the roof area is relatively small and painting it will make little difference to the energy use of the building.

In the case of apartments what will make a difference is lowering the amount of energy used in lighting, particularly by replacing halogen down-lights with more efficient compact fluorescent or LED lights. For office buildings what will make a difference is lowering the amount of heat generated by office equipment. Office equipment wastes energy in two ways: by directly using electricity and by the waste heat having to be extracted from the building by air conditioning. Some simple measures are to turn off screen savers of computers, set energy savings setting to turn the screen and disk drives off after a few minutes of non use and switch the computer to low power or off. Other measures include buying more energy efficient and less equipment. Two of my favourite savings are to buy lower power (cheaper) computers and to buy fewer printers.

ps:I n some cases Insulating Paint Additive might help for a roof. Perhaps even more exotically, reflective paint might be used. This would allow a roof to appear to be a dark colour, but would reflect light strongly from the direction it was shone. In the case of sunlight, it would be reflected back up into the sky.

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Saturday, December 26, 2009

Insulating Paint Additive

Last week I purchased a packet of "Thermilate" insulating paint additive. This cost AU$43.64 from The Natural Pain Place in Newton Sydney. The packet holds about one litre of white power and is intended to be added to four litres of paint. The power consists of what are claimed to be small hollow ceramic spheres, which contain a partial vacuum and therefore have a high insulation value. The effectiveness of this material for insulation has been called into question, but my intention was to try using the reflective properties of the material for a projection screen painted onto a wall. This was after the failure of my attempt using White Knight "Reflect-All" light reflective paint.

However, Christmas intervened before I could try the paint as a screen. I had far more of the paint additive than needed for tests. There was a small concrete deck to be painted before a Christmas party, and the additive was gritty, so I used some of it as a non-slip additive for the deck paint.

The material has a chalky texture and I was worried it would not mix well with the oil based heavy duty deck paint I was using. But it mixed in easily. The resulting paint was of a different consistency with the grit clearly visible in the paint.

The paint when on well using an ordinary roller. However, when it dried there were white chalky streaks visible in the high gloss dark green paint, showing the individual roller marks. Also the paint was a noticeably lighter colour that the original. The paint also had a slight white sheen, which was not really wanted for a deck, but indicates it may work well for a projections screen.

I found that by using a cross hatch pattern with the roller for a second coat, I was able to get an acceptable finish with the paint. The white chalky patches were still visible, but broken up in a random pattern were aesthetically pleasing on the slightly rough finish of the concrete deck. Glossy dark green paint must be about the hardest to hide the white additive in and, if used with typical a semi-mat off white paint, the additive should not be visible.

The additive provided a very good non-slip surface and is comparable in price to the grit additives sold for paint. The surface felt less cold than untreated paint on the same concrete, suggesting that the additive has some insulating effect.

The insulation claims for the material appear excessive and not credible. However, tere have been some independent tests which suggest some value for the material. Assuming the packet contains 1 litre of power, dispersed in 4 litres of paint this would cover about 10 square metres of wall (assuming two coats), forming a layer about 0.1 mm thick. The spheres would have to have exceptional insulating properties for a layer this thin to have a insulating value comparable to conventional insulation, which is hundreds of times thicker.

However, in situations where no conventional insulation can be installed, the paint may have some value, as discussed in Paul Teather's 2004 thesis: "A study of Ceramic Microsphere Insulation with a consideration of the wider implications". Applying insulation is a complex business, whereas adding the powder to paint is not. As an example if there is an uninsulated solid brick or concrete wall, any insulation would be better than none. However, it is not clear if this additive is much more effective than just a thicker layer of paint.

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Tuesday, December 08, 2009

Growing Packaging and Insulation

EcoCradle is a new type of packaging and insulation grown from fungus and garbage. The material is grown from a mix of waste organic material and fungi spores. The mix is placed in a mould of the shape of the required packaging or insulation and placed in a cool dark place. The fungus grows, consuming the organic material and filling the mould with a lightweight fibrous material. The material is made of fungus and so is biodegradable (but has to be protected from moisture).

This technique has potential as other fungi have the consistency of wood and could be used where a harder material is required. Also in manufacturing terms it would seem to make more sense to create this material in a two step process: first grow the fungus, then form the material later into the shape required, using pressure and perhaps water. This would be similar to the way packaging is formed from waste paper and the way medium density fibreboard is made from wood fibres.

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