Subject: SOLAR POWERED AIR CONDITIONER?

From: "G. Ige" <[email-masked]>
Date: Mon, 19 Aug 1996 20:09:12 -0700

Is it possible to power air conditioner by means of a combination of
solar, batery and wind generator? Any help will be appreciated.

Thanks in advance.

Gabriel Ige

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From: [email-masked] (hh7)
Date: 20 Aug 1996 09:00:10 GMT

Yes, it is possible.

A past issue of Pacific Friend issued by Japanese Government
carried an article on it.  The company involved was SANYO.
Utility power was used to reach the set temperature and then
solar energy from photovoltaic cells maintained it.  For
more information you may have to write Sanyo, Japan.  No
technical information was given in the article but photographs
and descriptions of the system were included.

---

From: [email-masked] (hh7)
Date: 20 Aug 1996 08:59:12 GMT

Yes, it is possible.

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From: [email-masked] (Dave Wood)
Date: Tue, 20 Aug 96 18:37:22 GMT

In article <[email-masked]>,

>solar, batery and wind generator? Any help will be appreciated.

Sure, it's possible. Probably not optimum or very efficient, though.

	You could use a solar/wind/battery system and then an inverter to make 
120 VAC (or whatever your local electricity is) to run an air conditioner. Or
you could use a car air conditioner and use a 12 V system. 

	Air conditioning is a big electricity user. It is usually more 
efficient to minimize the need for AC by things like adding insulation, 
putting reflective film on windows, planting trees to help shade the house,
putting arbors/porches etc. to help shade the house.
	Other ways to help cool the house are thermal mass transfer systems 
like dew ponds, underground air ducting, cooling lots of brick/rock/concrete
to absorb heat during the day, using an evaporative cooler etc.
	It's usually worth doing passive or non-AC cooling is worthwhile
even if it's only to minimize AC use- even if it doesn't completely rid you of 
the need for AC.

-Dave

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From: [email-masked] (Gene A. Townsend)
Date: 20 Aug 1996 19:17:03 -0700

>Gabriel Ige

Since you did not mention "air conditioner" type desired, I must
interject a thought...

If your locale is a dry region, such as the desert southwest, and
evaporative coolers are used, then this approach is entirely powerable
by photovoltaics directly.

Evaporative coolers are considered "air conditioners" in the broad
sense.  

The least expensive approach is to purchase a standard size household
unit, and convert for twelve volt operation.  This requires a twelve
volt DC motor of around 1/4 th horsepower for nearly 3000 CFM cooling
using appropriate ratio belt drive to properly load motor with
centrifical fan.  A 12 volt water pump from an RV dealer completes the
conversion.

It is best to use a large, oversized cooler and blower, rated say 7500
CFM or so @ 1 h.p., and to turn blower at slow rpm using a smaller
motor and higher drive ratio.

Hope it helps you get cool, dude!

Gene A. Townsend

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From: [email-masked] (dsg)
Date: Wed, 21 Aug 1996 02:54:44 GMT

::Is it possible to power air conditioner by means of a combination of
::solar, batery and wind generator? Any help will be appreciated.

::Thanks in advance.

::Gabriel Ige

Gabriel: go to my site at http://www.chatlink.com/~soltherm/

the solar thermal electric generators there can be used for
refrigeration. In fact, electricity losses could be eleminated
completely, and the solar collectors can "make ice"
with no moving parts. VERY efficient.

Homepower authors, did just this, recent article....
-some guy named "Moth" or something...

cherrios.
dsg

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From: [email-masked] (Steve Marshall)
Date: Wed, 21 Aug 1996 11:24:52 GMT

I test industrial chillers (air conditioners, heat exchangers, etc).
One of the interesting systems I found out about when I began in this
line of work is absorber types of air conditioning equipment.

I have said to the air conditioning technicians on many occasions, is
that whoever designs a backyard solar fired air conditioner is going
to make lots of money.

This is the way I see it being done.....

Commercial absorbers (1000 btu/ton) units use lithium bromide as a
carrier agent. The actual refrigerant is water. Lithium bromide has a
very strong 'attraction' to water/water vapor.  When the two are in
the same vessel the LB will try to absorb the water. This is used as a
'pumping mechanism" in a very low pressure vessel to cause water to
boil in the temperature range used in these systems. Steam is normally
used to provide the heat to 'boil off' the lithium bromide from the
water. The water  is then sprayed around the pipes used for cooling,
absorbing the heat and vaporizing. The lithium bromide then
attracts/combines with the water vapor and is pumped back to the steam
section to be separated again.

Vey little power is needed for the pump, comparatively speaking.
Absorbers are normally used where steam is used in some manufacturing
process where boilers are used anyway.

Downsizing the unit and substituting a solar furnace, or focusing
solar collector seem to be the engineering problems to overcome.

Arizona, Golan Heights, etc would seem to be excellent areas to
benefit from this technology

I understand that RV's use ammonia systems with either electric heat
or gas flame to boil the ammonia off in similar fashion. Maybe solar
furnace could be applied here as well.

If you have the space, farm animals, and inclination, heat could also
be produced by biomass methane generation.

---

From: [email-masked]
Date: 21 Aug 1996 06:12:03 -0700

I hope we will overcome some hurdles soon, but mechanical refrigeration,
like electric or direct-fired water-heaters have a lock on the commercial market.
The solar solutions are still cumbersome and mostly experimental at the residential
level.	
	3 tons of mechanical refrigeration takes about 4kw of power at 200-240
vac. The duty cycle is about 30-50% on. Can you afford the batteries and inverter?
	Evaporative cooling is very effective when dew points are below 55 F. It
does depend on rapidly changing the air in the conditioned space. Slow air changes
will not be comfortable. Power drops to 1/2 - 1 kw, doable, but the duty-cycle is
nearly 100%. A 12 volt 1/2 h.p. motor needs more than 40 amps to run! Do the math
1/2 h.p. = 500 watts (actually more like 700, but pretend). 500 / 12 = 41.666....
	Absorber systems seem best suited since the solar energy is directly applied.
The drawback is absorbers are complex machines and very large (if cooling 1000 
sq. ft. or more). If they were manufactured on the scale mechanical refrigeration is,
they would be very cheap and popular. The availible equipment is generally much
larger than an average home owner would tolerate. Solar panels would cover the
entire roof. Not a problem for progressive thinkers in this group, but something 
else to overcome.
	I would like to hear from anyone using solar-powered active cooling.
	
Jim Sullivan
[email-masked]

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From: clyvb@khan (Clive Bittlestone)
Date: 21 Aug 1996 17:57:27 GMT

I was wondering if anyone has heard of a non-evaporative household
conditioner.

I remember seeing a gas powered fridge, and thought maybe
some solar concentrator could be used instead of a gas flame,
and photo-voltaics for a pump ? Someone said they used ammonia and water

sorry if this is an old question, I only found this group 2 months ago,
and after some web searches, I found lot's on heating, but almost nothing
on cooling.

Cheers Clive B.

Gene A. Townsend ([email-masked]) wrote:
: "G. Ige" <[email-masked]> wrote:

: >Is it possible to power air conditioner by means of a combination of
: >solar, batery and wind generator? Any help will be appreciated.

: >Thanks in advance.

: >Gabriel Ige

: Since you did not mention "air conditioner" type desired, I must
: interject a thought...

: If your locale is a dry region, such as the desert southwest, and
: evaporative coolers are used, then this approach is entirely powerable
: by photovoltaics directly.

: Evaporative coolers are considered "air conditioners" in the broad
: sense.  

: The least expensive approach is to purchase a standard size household
: unit, and convert for twelve volt operation.  This requires a twelve
: volt DC motor of around 1/4 th horsepower for nearly 3000 CFM cooling
: using appropriate ratio belt drive to properly load motor with
: centrifical fan.  A 12 volt water pump from an RV dealer completes the
: conversion.

: It is best to use a large, oversized cooler and blower, rated say 7500
: CFM or so @ 1 h.p., and to turn blower at slow rpm using a smaller
: motor and higher drive ratio.

: Hope it helps you get cool, dude!

: Gene A. Townsend

---

From: john <[email-masked]>
Date: Wed, 21 Aug 96 10:32:24 GMT

> solar, batery and wind generator? Any help will be appreciated.
Most attempts to get cool when the sun is shining are dispite the stupendous 
quantity of heat.
In south africa they used to cool wine etc in a wet sack on the roof of a 
moving car.
So I recomend a fan that is solar powerd or not and a wet sack for starters.
The next evolution step a tank of water shaded from the sun with a fan blowing 
on it.
In the tank a 50m (14Ukp) hose pipe coiled to act as a heat exchanger.
Conected to radiaters normally meant for warming via cheap water pump that also 
could be solar powerd.
With convetional conditioners water condensing has to be collected and dripped 
outside but if the radiaters are bg enough on the inside perhaps this wouldn't 
be a problem.
The only obstical is actually trying it and I suspect the old insulation in the 
walls will need improving plus shading from the sun with external shutters, 
that also could shade frost in winter. -- 

Yours sincerely....John G.*?*?*?*?*? Us Neuron's don't KNOW that much, period.
*?*?*?*?*?*?*?*?*?*?*?*?*?*?*?*?*?*?*?*?*?*?
(Everybody wants to be certifiably nice on this tide of awesome tech' power.)c?
(Posts mispelt or not should be written with content to be worth saving
so as apathy doesn't drown lurkers)c?

---

From: [email-masked] (Marcel)
Date: Wed, 21 Aug 96 21:33:49 GMT

Answer for question below:

Yes its possible,
You generate energy and you can do anything you want with this energy.
Its technical possible to use this energy to drive a air-conditioner system.
The problem is that the countries how need this are mostly pore and do not see 
that the investment make after a few years a profit. 

I was bizzy with this subject for Colombia.
People have now money and do not see its saves money.

Best Regards

Marcel
Holland (the Nederlands)
Aan 8/20/96 5:09AM, in bericht <[email-masked]>, "G. Ige"

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From: [email-masked] (Robert Pettus)
Date: Thu, 22 Aug 1996 01:29:36 GMT

In article <[email-masked]>,
>furnace could be applied here as well.

I just read in a library book ( that I had to return yesterday ) is that
LiBr systems were preferred by solar systems.  They explained that solar
water systems generate water in the 150-180 degree range ( again, I'm
working from memory, so temps are approx. )  The LiBr systems can work
quite well in that temperature range.  However, the Ammonia systems
require temps in excess of 200 degrees to function correctly, and these
temps are difficult to obtain from solar collectors, and if done anyway
can lead to degrading of the collector.  The disadvantage of the LiBr
system is that it operates at a hard to maintian low pressure, freeze up,
etc.  

Note; I defer to REAL HVAC techs here, I was just reading about a subject
that interests me.  

Robert
[email-masked]

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From: [email-masked] (Eugene Searl)
Date: Thu, 22 Aug 1996 04:40:14 GMT

clyvb@khan (Clive Bittlestone) wrote:
you might try a search on +absoption+refrigeration
I found
http://www.elsevier.nl/catalogue/SA4/430/09710/09711/28699/28699.html 
at lycos. I'd try searching all the search engines and be sure to use
the and options so that both words are required.

---

From: "Darren, Debbie & Joshua" <[email-masked]>
Date: Thu, 22 Aug 1996 11:06:14 -0400

There is a couple in Florida that are biulding a solar home (they have a
page at http://www.phys.ufl.edu/~liz/home.html) and I asked them about
the air conditioner that they mentioned on their page. This was part of
their responce.....I hope it helps give you some ideas.

        "I believe you asked about the air conditioner.  It is based on 
solid state thermoelectric chips.  The chips take low voltage (a few 
volts) high current (about 20 amps) power, and one surface gets very
cold while the opposite surface gets very hot.  You let air pass through
a copper tube connected to the cold side, and you cool the hot side with 
air or water.  No moving parts is a bit of an exageration, as I will use 
a small water pump for cooling the chips, and a fan in the house will 
move the cool air into the house.  Our unit is designed to cool a 600
sq. ft. house, and should have an efficiency (coefficient of
performance) of about 1.2.  The total cooling power is about 800 watts. 
It will be connected directly to the PV modules and run all the time the
sun is up, providing a constant trickle of cool, dry air."

Darren

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From: altavoz <[email-masked]>
Date: Thu, 22 Aug 1996 11:51:51 -0700

> sun is up, providing a constant trickle of cool, dry air."

++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++=

I hate to destroy your idea , but we all have purchased the Coolatron
type frigs and know exactly how much they cool . 
" a few volts at 20 amps.....800 watts"  Theres a big problem with
your math .  How about 80 watts !!
  80 watts would cool a beer in 1 hour . 

I've thought of living off grid for 25 years and did from 1991 til
1994. Cooling must be done with water. In muggy climates this is a
big problem .

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From: [email-masked] (Gene A. Townsend)
Date: 22 Aug 1996 17:47:08 -0700

>Darren

Darren:

I have worked professionally with thermoelectric coolers for ten
years.

Their effeciency is high only when the temperature drop is small.

In other words, when they are providing little cooling, they are very
effecient.

With a modest temperature drop of say 30 deg. C, they produce about 10
W of cooling using 8A at  10  vdc, or about 80W for an effeciency of
only  1/8 or a COP of 0.125.

Standard refrigeration units operate at around COP of 4.0.

Similar low effeciences are typical when they are used as thermal to
electrical generators as well.

Cheers

Gene A. Townsend

---

From: Carlos Portela <[email-masked]>
Date: Thu, 22 Aug 1996 23:58:38 -0700

> solar, batery and wind generator? Any help will be appreciated.

Air conditioners are available for renewable energy homes,
but are expensive.  Consider these systems if other cooling
strategies don't work.  Here is a listing for one unit from
the Jade Mountain web site:

> The Chiller
> Natural gas or propane air conditioning - High
> efficiency without ozone damaging CFC's
>
> Uses the same kind of absorption cooling technology used
> in our gas refrigerators for maximum cooling at minimum
> operating costs. The only air conditioning system
> efficient enough for practical use with alternative
> energy systems. 3 ton size uses 75,000 BTU/hr. and
> 875 watts for the 1/3 HP fan motor and pump. Available in
> sizes with up to 25 ton cooling capacities. (Request
> information on larger units.) You can also combine with
> one or more indoor fan coils.
>  3 ton Chiller (FC505) $4200

For more info., see this web page:
http://www.indra.com/jade-mtn/fans.html

Good luck,

Carlos Portela
-- 
3-D Software
P.O. Box 220, Mapleton OR  97453  USA
[email-masked]
http://www.teleport.com/~solar3d

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From: [email-masked] (Bobo the Clown)
Date: Sun, 25 Aug 96 18:36:51 GMT

---

From: [email-masked] (Mark Fellhauer)
Date: 25 Aug 1996 14:07:02 -0700

>solar, batery and wind generator? Any help will be appreciated.

The answer is yes.  A number of HVAC manufacturers are now making
small residential gas powered chillers (absorbtion units).  It is
possible to heat the reaction chamber with active solar hot water, at
least partially, if not totally.  I have seen a number of these
houses, including one owned by an ASU professor here in Phoenix.

It is probably more practical to power the pump and fan(s) with
photovoltaics and take the total natural gas or LPG option in running
the reaction unit on the chiller, IMHO.    

On the whole, If I were building or retrofitting a house, I'd go with
a natural gas chiller/heater rather than "conventional" AC/Gas Furnace
or Heat pump option.  First, they're cheaper to run.  Second, they use
no CFC's.  Third, they have fewer moving parts and are quieter.
Fourth, they are easier to zone.  

Mark Fellhauer

---

From: rgans <[email-masked]>
Date: 25 Aug 1996 15:07:04 -0700

Mark Fellhauer wrote:
> Mark FellhauerI live in Phoenix and have been looking for sources of absorbtion units. 
If you know of any please post them. Thanks
Richard Gans

---

From: [email-masked] (Mark Fellhauer)
Date: 26 Aug 1996 19:35:03 -0700

>If you know of any please post them. Thanks

Real Goods is a place to start, although they are a bit pricey and
preachy.

The Modern Refrigeration Handbook is a good reference.  A current ed.
can usually be found in the Library or Barnes & Noble.

Mark Fellhauer

---

From: [email-masked] (PVCAD, Inc.)
Date: 26 Aug 1996 20:53:03 -0700

>Gabriel Ige

I have installed three types of systems with air conditioners on dc systems.

We have operated custom high efficiency (SEER about 16) air conditioners
rated at 3 tons (36,000 BTU/Hr) from 24-volt battery systems to provide
backup cooling to cellular telephone cell sites in Phoenix.  Cooling is required
to maintain operation as the heat generated in the building would over heat
the building within one hour in the summer here (46-50C, 115-120F).  A major 
problem is the starting current of very high efficiency compressors with locked
rotor currents of over 100 amps with running current under 20 amps, at a
nominal 230 VAC.  We use a stacked pair of Trace SW4024 inverters and a 
special motor starter.  The Trace SW4024 can handle surges of only 80 amps.
The system works reliably, and could be part of a PV system.  This is large 
by renewable energy home standards.  Smaller or lower efficiency air 
conditioners would have less of a problem.  High efficiency units require
smaller battery sets and smaller PV or other power sources.

Trane used to make a variable speed heat pump that essentially was a
variable speed 3-phase motor controller (inverter) driving a special
compressor with a synchronous 3-phase motor.  This heat pump is
also high efficiency, but there is no surge due to the slow start of the
inverter.  There are two ways to operate this heat pump from PV systems:

1) Use inverters of suitable power (2 Trace SW4024 again) to supply 230
    VAC;

2) Connect a high voltage PV array to supply 380VDC into the 3-phase 
    motor controller (or a lower voltage into a maximum power tracking
   boost converter to produce 380 VDC).  In the USA this method does
  not fully meet the National Electric Code requirement for a hard 
  grounding of the PV array as the 380 VDC is produced from the
  heat pump boost circuit that is part of a power factor correction power 
  supply that results in a floating 380 VDC. The normal AC power is still
  required for the controls and evaporator motor in these test systems.

Both systems work, but the #1 design also allows other use of the PV
energy when the heat pump is not needed.  This heat pump is no longer 
available.  This work was sponsored by the Electric Power Research 
Institute (EPRI) and is still in process, no report is yet available.

Bill Kaszeta
Photovoltaic Resources International
Mesa  Arizona USA

---

From: [email-masked]
Date: Thu, 29 Aug 1996 09:19:45 +0300

> 1994. Cooling must be done with water. In muggy climates this is a

I am in a sunny, dry-summered climate. I can avoid most cooling needs 
through design - masonry construction, shading, vent stacks, etc. - but 
I am wondering how I can provide the small amount of supplementary 
cooling needed at the hottest points of mid-summer.

Can this be done evaporatively with PV-powered fans? Are there any 
problems with moisture in dwellings using evaporative cooling?

ALSO: How can I use solar for heating during our mild, wet winters? Is 
there any way I can store heat for the longer periods of cloud cover 
(which can last several days)? I would like to make use of solar hot 
water for this, as this equipment is widely available here.

Joshua

---

From: Raymond Bahm <[email-masked]>
Date: Sun, 01 Sep 1996 22:04:57 -0600

> cooling needed at the hottest points of mid-summer.
Yes!  Of course it does depend on the climate, and what you mean by
"dry-summered".  Evaporative cooling is standard technology here in
the Southwestern US.  What are the temperatures and relative humidities
at which you want to cool your building?  How do they vary daily?

> problems with moisture in dwellings using evaporative cooling?
PV powered fans can work -- but do the calculations first.  People
too often make the mistake of guessing too small, and then giving
up.
Generally if it is dry enough to get good evaporative cooling you
won't have a problem with moisture.

> water for this, as this equipment is widely available here.
Of course water does work, but calculate the amount and temperatures
required.  Our experience has been (generally) that after 5 years or
so, people tire of maintaining liquid collector systems.  The really
successful passive solar designs store the thermal energy in the 
building mass (just like you mentioned with the cooling).  This
however, usually has storage of about one day's length.  The longer
periods are covered by a backup heating system of some kind -- usually
just a traditional heating system.

The first thing to think about however is insulating your building.
Insulation is cheaper than almost any form of heating, for the energy
conserved.  (Of course this varies with the climate too.)
-- 
Ray Bahm  --  [email-masked]

---

From: john <[email-masked]>
Date: Mon, 02 Sep 96 01:36:11 GMT

> problems with moisture in dwellings using evaporative cooling?
Probably not in hot weather, since I have a cheap plastic humidity meter meant 
for greenhouses in every room and humidity is only a problem in autum and 
spring here in UK.
> ALSO: How can I use solar for heating during our mild, 
wet winters? Is > there any way I can store heat for the longer periods of 
cloud cover > (which can last several days)? I would like to make use of solar 
hot > water for this, as this equipment is widely available here. > > Joshua > 
For access to solar heat in winter I sugest cloche like extra glazing and 
removing the shade you mentioned you have for sumer some how.
Lots of cheap dustbin/ water butts with lids in the glazing space between walls 
and glass/plastic would store heat. -- 

*What is existance without socialising?*?*?*?*?*?*?*?*?*?*?*?*?