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TECHNO TALK: Hair today, gone tomorrow
SINCE I was a child I’ve had this fantasy of dressing up in a medieval suit of armour and having an all-out sword fight with someone also clad in medieval metal. The only problem is that people were a lot shorter 1 000 years ago.
The human race has evolved to be a lot taller than our flail-wielding ancestors. Squeezing oneself into a genuine suit of knight’s armour would be near impossible now — especially if you’re a beer drinker. This may make one wonder if we are still evolving today.
Most evolutionary biologists would argue that if we haven’t stopped evolving, our evolution has at least slowed down to a glacial pace. The main argument is that we have created and adapted our urban environments to best suit our current shape and form.
We have taken to sitting down a lot — whether behind a desk, on a sofa or in a car seat. When it’s too cold we take comfort behind our walls and cover ourselves with blankets. And now that things are heating up, we may blast air conditioners to keep comfortable. Human evolution doesn’t stand a chance.
Fortunately, evolution is technology’s best trait. Air conditioners have become more efficient and eco-friendly and can now be used to heat and cool a building thanks to a variety called a heat pump. Heat pumps are typically used to pull heat from the air or ground into a building to raise the temperature, but can also be put into reverse to cool a building.
How heat pumps work
Liquid refrigerant is pumped through the outside coils of an air-source heat pump. A fan pulls outside air over the coils, which absorbs the heat in the air and expands it into hot vapour. The vapour enters a compressor, which increases the temperature and pressure of the gas. The vapour then flows to indoor coils. The refrigerant condenses the vapour back into a liquid as it cools and flows outside to gather more heat. Meanwhile, the heat is pumped through the air ducts of your home and distributed throughout. This process can be reversed to cool the air inside your home. (Diagram: howstuffworks.com)
Heat pumps operate in a very similar manner to standard heating and air-conditioning units but without the need to install separate systems. They are also far more efficient than their ancestors as they do not burn fuel to condition the air but rather transfer it from one place to another. Heat pumps can also be used to heat swimming pools and can even fire up a hot tub.
I’m proud to inform that heat pumps are widely available in South Africa. A couple of good places to start perusing these are www.itssolar.co.za and www.heatpumpssouthafrica.co.za By providing your name, contact details and nearest city, a heat pump specialist will contact you within 24 hours. Prices for domestic heat pumps range from R10 000 to R15 000.
Heat pumps should of course be used in conjunction with other energy-saving techniques. Using fluorescent light bulbs and turning appliances off when not in use are the obvious ones, but it is also a great time to utilise the spring sunshine. Phantom loads are the less obvious energy drainers. When something like a cellphone charger is plugged into a live socket, but not into a cellphone, this actually drains more energy than would be used if a phone was charging.
So let’s all do our bit this sunny season to help the planet fend off global warming by being energy savvy and by using green devices such as heat pumps. I really don’t want to have hairy grandchildren.
“We must protect ourselves from the Global Warming… Top scientists in Colorado believe that Global Warming will strike two days before the day after tomorrow!” – South Park
I was walking past the fruit and vegetable section in a supermarket one winter’s day when I felt a powerful gush of warm air seduce my face. The seducer was a household fan that had a heated coil in its centre which heated the air to a remarkable extent.
I soon learned that these new heating devices are very considerate on their energy usage and weren’t badly priced either. However, our coldest winter yet is thawing to a close, and it won’t be long before we go to lengths to keep cool.
Contemporary air-conditioning systems are not only heavy energy consumers but also have an utter disregard for the ozone layer. At full volume a household air-con farts out enough greenhouse gases to chock a small elephant.
Thank the pope ScienceDaily have recently reported that scientists from Madrid have produced a solar-powered air-conditioner that is far more environmentally friendly than previous cooling systems. It is said to use a reduced amount of greenhouse gases and does not harm the ozone layer in any way.
The “Absorption Chiller”
Known as an “absorption chiller” the device makes use of solar and residual heat as an energy source. For the science people, the technology combines the use of lithium bromide solution with a reduction in the use of water, which supposedly damages the ozone layer and contributes towards the greenhouse effect.
More technically speaking, the absorption mechanism is capable of producing cold water at temperatures ranging from 7º C to 18º C when the sweating thermometer on the wall displays temperatures between 33º C and 43º C.
A look to the future:
The new cooling system seems to have arrived at a good time too. Last year 191 countries were involved in a signed agreement to avoid the use of ozone depleting substances as well as set a 25% consumption limit by 2010 (as compared to 1996).
By 2020 it will become law for all developed countries to replace all HCFC refrigerants, such as those used in air-conditioners, with green substitutes. No mention of developing countries however. I guess the ‘First World’ is quite content to continue selling the cheaper, more lethal air-conditioners to the ‘Third World’ forgetting that we all share the air that we breathe…
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