A short newsletter giving practical advice on minimising your energy for heating and cooling focusing on low cost easily implemented ideas.
How to improve evaporative cooler performance.
What does the future hold?
How do you minimise the biggest energy villains in modern houses?
In hard water areas the pad in an evaporative cooler can get clogged up with salts (mainly calcium salts). However this will usually dissolve in a weak acid. Try adding a litre or two of cheap vinegar to the tank and then run the cooler (make sure the pump is running). This should dissolve the salts and increase the airflow. Be careful to avoid getting vinegar on metal surfaces other than stainless steel. (If you do, rinse it off with water.)Back to Contents
At this time of year every magazine likes to look forward to predict the future. Who am I to buck the trend? Over the next ten to twenty five years I believe:
If we assume we are able to avoid a world war then the biggest problem will be due to the continued growth of the economies of China, India and other Asian economies. Many of the economies in South America and Eastern Europe will join this growth, exacerbating the worldwide production of greenhouse gases. The fact that climate change is man made will continue to become more obvious. Air conditioning of some sort will be in over 95% of Australian houses and the number of square meters of air conditioned area per house will continue to grow. This means the peak electricity demand in all of Australia will occur in summer and our electricity demand will continue to have higher peaks relative to the average demand. The power industry will continue to struggle to provide enough peak electricity. Energy shortages will force us to find lower energy ways of keeping warm and cool.
To address these problems, governments will be forced to impose some form of carbon tax. Carbon credit trading will become a major industry. This will lead to an improvement in the competitiveness of wind and solar. I believe that in the next ten years, the cost of solar-voltaic panels will drop to the extent that the penetration of solar electricity will become mainstream, and most people will have some, even if only as a backup for power failures. This trend will be encouraged as power failures during peak periods continue to increase in severity due to the increased air conditioning demand.
I believe that sequestration of CO2 from coal fired power stations will be implemented with great fanfare and then found to be useless. The CO2 will end back in the atmosphere.
Nuclear power will unfortunately expand until a number of terrorist attacks on different parts of the fuel cycle, make this option less attractive.
In order to reduce energy use, people will start to look at what it is that they are trying to achieve with air conditioning. They will realise that we are trying to make people feel comfortable. This will prompt the thought that cooling the air around people is not the only way to make them feel cooler. A number of technologies will develop to allow our air conditioning thermostats to be set higher in summer and lower in winter to reduce energy use without causing discomfort. These technologies will as a consequence make evaporative cooling more attractive and reverse the trend away from evaporative cooling. This will help slow the rise in electricity demand in Perth, Adelaide and Melbourne.
These alternative technologies will include intelligent fabrics that become more open when hot to allow greater ventilation. The actual deign of clothing will be forced to change. The biggest problem we have with clothing customs, is the business suit. Alternatives will be found that allow offices to float another couple of degrees warmer in summer without giving discomfort. In fact when I have finished my research into improving the comfort achievable with evaporative cooling, I intend to research this area.
The best conventional air conditioning is getting close to the theoretical performance limitations and further improvements will only occur through radical new approaches. One of these is radiant cooling where you try and cool the people directly rather than first cooling the air.
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The biggest energy villains in modern houses are the windows. We have built houses with walls of glass facing west and wondered why they are impossible to air condition. During the colder months the thin glass cools the layer of air next to it which then sinks to the floor and freezes your toes. We wouldn't expect an uninsulated galvanised lean-to to be comfortable in summer or winter, but we build rooms of glass which are even worse in summer. (You might think that glass is a better insulator than steel, which it is, but 4 or even 6 mm glass has negligible resistance to heat. For a single thickness of glass to give a useful amount of thermal resistance you would want it to be at least 300 mm thick!
Well you can now see the problem, but what is the solution? The first task is to be judicious in your use of windows if building a new building or extending. Your state government energy office will have plenty of good advice on this. In fact, you will find you won't be able to have walls completely of glass because it won't meet the current building regulations.
The second task is to keep the sun off the glass during summer. Generally on the north windows, an eave approximately half as wide as the window is high will do the trick. On West and east windows you can use trees (see CoolComfort issue 1), wide pergolas or external blinds. The quickest and cheapest is often blinds. South windows don't generally pose a problem as the sun is usually fairly low by the time it has travelled far enough south. However if the house is at a slight angle to South you may have a problem first thing in the morning or in the early evening. Planting appropriate shrubs or trees should fix this.
The third task is to increase the effective insulation value. The options are:
* Reprinted from CoolComfort Tips 2 with updates.Back to Contents
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