More about the humble dude

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Wow, you want-to-know readers never let me off easy!
Your questions about yesterday's solar water heaters need a whole new post.

1. OK, so today I telephoned the company that installs the dood shemesh pictured above.
The basic dood unit costs 2300 shekels = $614 =446 Euros.
Not bad, right?
Big savings on your electric bill when you let the sun heat your water for free.

2. The black collector panels connected to the water tank are NOT the same as solar panels.
The water inside the black coils heats up quickly (because that is what black does).
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Solar panels, on the other hand, collect heat and turn it into useable electricity.

3. The high percentage (90%) of Israeli families that have a dood shemesh is because we WANT them and believe in them, not because it is now mandatory.
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I found the following historical information in a good blog called MetaEfficient, The Guide to Highly Efficient Things:
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"These heaters were first installed when the country experienced a fuel supply crisis in the early 1950s. The government responded by severely restricting the times when water could be heated. Israelis in turn responded by purchasing huge quantities of solar water heaters. By 1983, 60% of the population heated their water with the sun. A law was eventually passed requiring the installation of solar water heaters."

4. We are poor in natural resources but rich with sunshine.
Israeli companies are the forerunners in alternative energy sources.

Hawaiian bloggers like Cloudia even tell me that our ORMAT company is harvesting power from their Big Island's volcano!
I think it is something like digging a well to capture geothermal fluid (steam?) and turn it into electricity.
But better you ask the Hawaiians about that. :)
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Hey dude

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For D Day at ABC Wednesday, let's take the Hebrew word dood.

A dood shemesh is a solar water heater.

Some 90% of Israeli families have one on their roof.
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The first two photos are not representative because these tanks are sitting on the ground, next to their house. (Well, actually it is a converted chicken house, with a roof apparently not strong enough for a dood on top.) But it is a good chance to show you a dood up close.

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Typical domestic units consist of a 150 liter insulated storage tank and a 2 square meter flat panel. The black collector panel collects solar radiation, heats the water, and passes it to storage in a pumpless, gravity-driven loop.

Convection carries colder water from the bottom of the tank into the collector and hot water rises to the upper intake on the tank.

After a few hours of good Israeli sunshine, you just open your taps and out comes near-boiling water!

If the sun hides for a few days (which happens only in winter), set the timer or flip the switch to run the immersion heater built into the tank for half an hour before you want a shower.

The ubiquitous dood shemesh is found on apartment building roofs,

on buildings in Jerusalem's Old City,

on Vatican-property roofs in East Jerusalem,

and on Bedouin village houses in the desert.

In short, EVERYWHERE.

On slanting roofs, the dood is often put in a horizontal fashion.

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Good system to let the sun do the work, eh? Saving fuel, saving money.

Would it, or does it, work in your country?

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In 2005 Spain became the second country (after Israel) to require solar water heaters by law.

And in 2010 Hawaii will require all new houses to have one!

How do you say dood shemesh in Hawaiian?

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