Skip to Content.
Sympa Menu

homestead - [Homestead] rain water collection was: Unpreparedness

homestead AT lists.ibiblio.org

Subject: Homestead mailing list

List archive

Chronological Thread  
  • From: Don Bowen <don.bowen AT earthlink.net>
  • To: homestead AT lists.ibiblio.org
  • Subject: [Homestead] rain water collection was: Unpreparedness
  • Date: Wed, 07 Feb 2007 09:05:05 -0800

At 2/7/2007, you wrote:
I've extolled the virtues of an elevated tank delivering gravity
water for many years. Not everyone has enough elevation to make it
sensible. A tank on a wooden platform delivers very low pressure. It
takes 2.1 feet elevation to create one psi at the faucet or
showerhead. A wooden platform for a water tank must be very strong
and sit upon a good footing.

The advantages of gravity are offset by its disadvantages. On order to get the water up you have to pump it. If you do not have the land profile an expensive tank stand must be built but the advantage is that once the water is up there you do not care if power is available because gravity is now on your side. If you have sufficient slope near your water source you can use a ram pump and completely ignore inefficiencies. Or if you have sufficient wind, a windmill can fill the tank when the wind is blowing.

I have been looking into rainwater collection. Rainwater tanks are usually located near ground level or slightly above. For plant watering a drip system is sufficient and that is all you need. For any other use you need to either mount a tank sufficiently above ground to generate the needed pressure or have some sort of pump. Pressure sensitive pumps into an accumulator are quite popular for wells and for a rain water system the pump need not be very big as it is not lifting. Pressure demand pumps are another alternative, these pumps run only when water is needed and nothing is accumulated. These do need power but as water is not being lifted the power requirements are minimal and a pump.

So it seems to me that for rain water collection the most cost effective system is ground mounted tanks directly feeding a drip system for gardening. For household use a pressure sensitive pump directly feeding the water system. I would use several pumps, one for household, another for animal watering, one for sprinkler irrigation, etc. Pumps would replace expensive towers and windmill systems.

I have lived with such a pump for the last couple of years. My trailer has a pressure demand pump running of the 12VDC system. It does not draw much current and is a small fraction of my total DC usage. A rain water collection system feeding a pressure pump driven off a small PV system would provide sufficient water in most areas of the country and would be much cheaper than drilling a well. The only way cheaper is a year round stream, hydro plant, and a Ram pump.

Regarding the compressed air pump, I always think of energy in and
energy out. What creates the compressed air? What is the source and
what is the cost? I suppose to evaluate the efficiency one would need
to compare some other pump cost per thousand gallons, say, and the
compressed air pump energy source the same.

When you change energy from one form to another you loose something. Compressed air is very inefficient because of heat and pumping losses. Converting gasoline or Diesel into rotating energy has significant losses then converting to compressed air generates more losses. Using electricity just moves the losses to a generating plant. Sometimes those losses are a trade off for other gains so must be evaluated carefully. Just keep firmly in mind "There ain't no free lunch."



Don Bowen Awl Knotted Up KI6DIU
http://www.braingarage.com
My travel journal
http://www.braingarage.com/Dons/Travels/journal/Journal.html

I am omnivagant.
From genegerue AT ruralize.com Wed Feb 7 12:34:05 2007
Return-Path: <genegerue AT ruralize.com>
X-Original-To: homestead AT lists.ibiblio.org
Delivered-To: homestead AT lists.ibiblio.org
Received: from fed1rmmtao106.cox.net (fed1rmmtao106.cox.net [68.230.241.40])
by lists.ibiblio.org (Postfix) with ESMTP id 0B3B74C011
for <homestead AT lists.ibiblio.org>; Wed, 7 Feb 2007 12:34:04 -0500
(EST)
Received: from fed1rmimpo01.cox.net ([70.169.32.71]) by fed1rmmtao106.cox.net
(InterMail vM.7.05.02.00 201-2174-114-20060621) with ESMTP
id
<20070207173404.HRMF1349.fed1rmmtao106.cox.net AT fed1rmimpo01.cox.net>
for <homestead AT lists.ibiblio.org>; Wed, 7 Feb 2007 12:34:04 -0500
Received: from [192.168.1.100] ([68.230.61.152])
by fed1rmimpo01.cox.net with bizsmtp
id Lha41W0073H4yBG0000000; Wed, 07 Feb 2007 12:34:04 -0500
Mime-Version: 1.0 (Apple Message framework v752.3)
In-Reply-To: <6.1.2.0.2.20070207084440.01d8c040 AT earthlink.net>
References: <18c9df6e0702012121j1345db5ew38b096e81188bbff AT mail.gmail.com>
<693450.36703.qm AT web61121.mail.yahoo.com>
<18c9df6e0702021016vbb3c128ub584eda497ee54eb AT mail.gmail.com>
<45C386F8.1040604 AT bellsouth.net>
<18c9df6e0702021106u265b2e42m45be05e5ba098e2c AT mail.gmail.com>
<45C38CC2.2070005 AT bellsouth.net> <45C770DD.3020905 AT harborside.com>
<45C7B669.8010900 AT bellsouth.net> <45C90493.3000704 AT harborside.com>
<45C93343.2070102 AT harborside.com>
<C91BF687-4E87-4726-9920-45985A2BB444 AT ruralize.com>
<6.1.2.0.2.20070207084440.01d8c040 AT earthlink.net>
Content-Type: text/plain; charset=US-ASCII; delsp=yes; format=flowed
Message-Id: <B71B0385-0D43-476F-BE7E-2D93B65378C8 AT ruralize.com>
Content-Transfer-Encoding: 7bit
From: Gene GeRue <genegerue AT ruralize.com>
Date: Wed, 7 Feb 2007 10:34:00 -0700
To: homestead AT lists.ibiblio.org
X-Mailer: Apple Mail (2.752.3)
Subject: Re: [Homestead] rain water collection was: Unpreparedness
X-BeenThere: homestead AT lists.ibiblio.org
X-Mailman-Version: 2.1.9
Precedence: list
Reply-To: homestead AT lists.ibiblio.org
List-Id: <homestead.lists.ibiblio.org>
List-Unsubscribe: <http://lists.ibiblio.org/mailman/listinfo/homestead>,
<mailto:homestead-request AT lists.ibiblio.org?subject=unsubscribe>
List-Archive: <https://lists.ibiblio.org/sympa/arc/homestead>
List-Post: <mailto:homestead AT lists.ibiblio.org>
List-Help: <mailto:sympa AT lists.ibiblio.org?subject=HELP>
List-Subscribe: <http://lists.ibiblio.org/mailman/listinfo/homestead>,
<mailto:homestead-request AT lists.ibiblio.org?subject=subscribe>
X-List-Received-Date: Wed, 07 Feb 2007 17:34:05 -0000

I have been looking into rainwater collection. Rainwater tanks are usually
located near ground level or slightly above.

In freezing areas I would opt for an underground cistern. Except for drip irrigation you need a pump anyway, so lifting the water another eight feet is no big deal.





Archive powered by MHonArc 2.6.24.

Top of Page