2aHawaii

General Topics => Preparedness and Survival => Topic started by: knowledgeispower on August 04, 2010, 09:16:31 AM

Title: Solar Power
Post by: knowledgeispower on August 04, 2010, 09:16:31 AM

I'm interested to hear and learn what solar powered devices Hawaii residents are using.  This could be divided into several categories including:

1.) Water solar heating (probably the most common)
2.) Small device recharging
3.) Small battery (12v) storage for short term emergencies
4.) Large scale solar collecting and storage

I would like to hear people talk about:
a.) Devices that the use and can recommend or advise to steer clear of (limit to first and second hand knowledge if possible)
b.) Devices, system designs, websites, and other learning resources that utilize solar energy in any capacity.

Regards,
KNOWLEDGE IS POWER

Title: Re: Solar Power
Post by: knowledgeispower on August 04, 2010, 09:23:33 AM

I stumbled across this device (http://www.mage-watermanagement.com/) while discussing the process of basic water desalination using solar power.  I learned this tried and true method in Boy Scouts many years ago, and have used it several times with fresh water and only once with experimental water desalination.

The idea is straightforward.  Using solar energy, you convert the salt water into freshwater by heating the water until it vaporizes, then collecting the condensation in a secondary container.

(http://www.watercone.com/pics/scetch300.gif)

This device is sold and manufactured by Mage Management (http://www.mage-watermanagement.com/)

(http://www.watercone.com/150/salt150.jpg)		(http://www.watercone.com/150/work150.jpg)		(http://www.watercone.com/150/harvest150.jpg)
1.             Pour salty / brackish Water into pan. Then float the   Watercone(r) on top.             The black pan absorbs the sunlight and heats up the water to   support             evaporation..		2.             The evaporated Water condensates in the form of droplets on   the inner             wall of the cone. These droplets trickle down the inner wall   into a             circular trough at the inner base of the cone.		3.               By unscrewing the cap at the tip of the cone and turning the   cone               upside down, one can empty the potable Water gathered in the   trough               directly into a drinking device.

They state that:

"The             WATERCONE(r) system can be referred to as a one step water   condensation             process with a 40% effectiveness degree (GTZ Germany). Based   on evaporation             levels of 8.8 Liters per square meter (average solar   irradiation in             Casablanca, Morocco), the WATERCONE(r) (with a base diameter   of roughly 80 cm) yields between 1.0 to 1.7 Liters of condensed water   per day (24             hours). The salty / brackish Water evaporates by way of solar   irradiation             and the condensation from that Water appears in the form of   droplets             on the inner wall of the cone. These droplets trickle down the   inner             wall into a circular trough at the inner base of the cone." This system makes a great deal of sense here in Hawaii as a fail safe water collection resource, since we have an unlimited supply of sea water at our disposal. Thoughts? Regards, KNOWLEDGEISPOWER

Title: Re: Solar Power
Post by: Tom_G on August 04, 2010, 10:33:39 AM

I like that cone dealy.  Between 1 and 1.7 liters per day isn't a lot, though.  That's 2-4 Watercones per person to reach a gallon a day. 

There is a technique called "solar water purification" that involves putting fairly clear water (as in not muddy) in a clear plastic bottle then leaving it on a reflective surface (correlated steel roofs are kind of the default) for a day.  The UV from the sun kills parasites and microorganisms in the water.  Very big in 3rd world nations. 

A good-sized pocket magnifying glass, something with a 2" lens or better, is a fantastic fire starter.  Of course, you have to start your fire before the sun goes down, but it works reliably and is non-consumable. 

Those "space blankets" (the little Mylar survival blankets that come in a package about the size of a deck of cards) are phenomenal for regulating heat.  Of course you can wrap up in one to stay warm, but you can also use one as an amazingly effective sun shade.  Not only can it protect you from the sun, but it's bright as Hell and can be seen for miles.

Simple black jugs are an effective way to heat water for bathing.  Many camping outfitters sell solar showers, black vinyl bags designed to be hung from trees.

Solar cigarette lighters are also decent fire starters.  These are just small parabolas of polished metal that focus the sun's rays on a fixed point. 

Photovoltaic battery chargers are good for keeping small electronics charged.  Again, these are available at camping outfitters.  You can use one to keep your cell phone or GPS operating, but they are woefully inadequate for anything more demanding, such as recharging a dead car battery.

As you may be able to tell, I've long been fascinated with making use of the sun's power!  However, I am not one for throwing money at neat toys.  I like the simple, the nearly-free. 

Title: Re: Solar Power
Post by: 2aHawaii on August 04, 2010, 07:59:52 PM

Here was an interesting site I found while browsing YouTube the other day. http://www.greenpowerscience.com (http://www.greenpowerscience.com) They also have a YouTube channel (http://www.youtube.com/user/GREENPOWERSCIENCE).
There are some fun uses of solar power. It's about evenly distributed between fun and serious stuff. The coolest is the Fresnel lenses they have. They are like giant magnifying glasses.

I have looked into what it would take to get our house off the grid, and the initial investment ends up being about $20k doing it ourselves and double that to get it installed by someone else. That's for a 5kw system. Pretty moderate energy usage. Of course being off grid, you need a large amount of battery packs and maybe a diesel generator to help you on the days there is no sun.

With that cone, it looks like you only get a little water for the amount of work you have to put in. Better to go with water treatment if you have it.

Title: Re: Solar Power
Post by: tonsofguns on August 14, 2010, 12:15:09 AM

The cone is for desalination and not purification. I would still purify after using the cone though.

I wouldn't trust that plastic bottle in the sun deal, especially since it has "works great for third world countries" as a selling point. That's why they are third world because  they can't buy germicide tabs or spare the fuel to boil water.

When you folks go mountain just don't forget your fire kit and canteen cup too!