Category Archives: water

Thermosiphoning Passive Solar Water Heater

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Build it Solar brings it again! This might be common knowledge but, heat rises and cold falls. This is the action behind thermosiphoning.

The short and sweet of it is that you run some cold water through metal pipes that are being hit by the sun to heat it. You have a circulating system where water from the tank (it’s raised higher than the pipes) falls as it cools, there by flowing to the heating pipes. As this water heats from the sun, it rises to exit the pipes and ends up in the tank again, this time on the top. This leaves you with hotter water on top and colder water on the bottom, circulating and heating more and more.

If that explanation left your head spinning, then the link to this project should help.

I first heard of thermosiphoning thanks to Ampersand Project. I might be lucky enough to go there towards the end of the year and help with a retreat.

Raised Field Agriculture in the Lake Titicaca Basin

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Raised Field Agriculture
While reading my new awesome Permaculture Magazine I was struck by an article that spoke of an ancient Incan way of agriculture. This is called Raised Field Agriculture. People would dig up canals and pile the dirt to create raised beds. These canals help the plants by providing water most, if not all, of the year. This also creates a micro climate because of heat retention from the waterways, thereby protecting the plants from frost. If that is not enough to get you thinking of renting some heavy machinery… it’s reported that fish could have been raised there, creating a kind of aquaculture that at the same time replenishes the soil with some needed Nitrogen. Did I forget to mention canoeing?
For LOTS more on the subject, shoot on over to Clark L. Erickson’s page. Also About.com has some good info.

Rain Water Collection

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Being that it’s raining like it’s monsoon season here in LA, I thought I’d post some info and resources on rain water collection. So as you hear that rain falling, think of all it could be doing for us…

The basic principle uses rain gutters to re-purpose rainwater that would otherwise run down the street and onto storm drainage. This water could be used for replenishing the local water table, landscaping/gardening and home use. Your options vary from a simple barrel with a hose attached, and placed at the output of your gutters to far more advanced and costly methods. Such as the one employed by the Clovelly House which houses many interesting technologies under one roof. Read up more on their “green wall“.

As always Builditsolar has a lot of info on the subject.

But how much water can you harvest? Generally for every inch of rainfall you get .62 gallons or 2.34 liters per square foot of roof. Calculate your average rain fall (this is for my zip code, you can just put yours on the address bar). This helps when considering what size container you’ll be needing. Also be aware that some states own the rights to ALL the water and you would need to get a permit to harvest it. Colorado is an example of this. (Thanks Wikipedia)

This interesting Texas Manual on Rainwater Harvesting states some of the reasons to adopt this practice:

  • The water is free; the only cost is for collection and use.
  • The end use of harvested water is located close to the source, eliminating the need for complex and costly distribution systems.
  • Rainwater provides a water source when groundwater is unacceptable or unavailable, or it can augment limited groundwater supplies.
  • The zero hardness of rainwater helps prevent scale on appliances, extending their use; rainwater eliminates the need for a water softener and the salts added during the softening process.
  • Rainwater is sodium-free, important for persons on low-sodium diets.
  • Rainwater is superior for landscape irrigation.
  • Rainwater harvesting reduces flow to storm water drains and also reduces non-point source pollution.
  • Rainwater harvesting helps utilities reduce the summer demand peak and delay expansion of existing water treatment plants.
  • Rainwater harvesting reduces consumers’ utility bills.

If you want a long but rewarding read on the subject; check out this source book from the United Nations.