Sustaining Future

Friday, September 21, 2007

Magnetic Refrigerator Needs No Electricity

From the post:
Scientists at the Technical University of Denmark created a refrigerator that uses magnets to cool instead of electricity by finding a cooling method which uses magnetic materials instead of electricity.

Frankly, I don't think the writer knows what s/he is writing (although the source is from Ministry of Foreign Affair, Denmark). First of all, magnetic material is physical objects (like a magnet for example) and electricity is a form of energy. I cannot see how a material can replace energy without replacing the material after the energy stored in the material has been depicted. Like you can use a battery to store electrical energy, you need to replace or recharge the battery when its stored energy is used up.

In term of increasing the efficiency of refrigerator, use a horizontal door for a refrigerator . The density of cool air is higher than hot air, every time we open a refrigerator with a vertical door, cool air from the refrigerator flows out and hot air gets in. Energy is needed to remove the heat that gets into the refrigerator. By using a horizontal door (like a deep freezer), as you open the refrigerator, no cool air gets out. The need of maintaining the low temperature requires minimum energy. I have reported that Tome Chalko at Mt. Best Australia has converted a freezer into a refrigerator which consumes about 0.1 kWh a day.


Green tech, when you will take off?

Harry Fuller pointed out in Oil up, your U$ money’s down and that’s happy news in green tech that as oil price skyrocketed, US$ record low (against the Euro) and Saudi Arabia may stop pegging its economy to US$, these are all good sign for green technologies.

For consumer green energy (such as solar power, rooftop wind turbine), the investment is usually upfront. At the moment, most of the investment will be looking at a 10 to 20 years period for economical return. This is far too long for ordinary people to take green energy as a viable option.

My guess is that when the return can be achieved within 5 years, green technology will take off. What do you think?