Conference 7.286::home_work

I assume what you want is a thermostat that will turn the pumps on at a certain 
temperature and then turn them off when the temp goes back below this.  We had 
to get a thermostat like that for our solarium.  We wound up getting one that 
is made for turning on attic fans.  You'll have better luck finding them at a 
heating and cooling supply house than at an electrical supply place.

Paul

Grainger's in Manchester NH has all sorts of thermostatically activated 
switches. You might try looking thru their catalog for one that will fit 
your application.

    There's a place in N.H. called "Solar Componets Inc." They sell
    many solar accessories including temperature sensors and controllers.
    A typical sensor will run you about $10-$15 each and a controller
    from $50-couple hundred (depending on programmability). Most "basic"
    controllers turn on when the temp in the collectors is 20 degrees
    warmer than the "other sensor" which is usually a water tank. They
    turn off when the temp differential is around 3 degrees. If this
    is fine for you then you can get one of the cheap controllers, if
    you want more flexibility, then you'll have to go for a more expensive
    one. Most comercial controllers use the same sensors. 
    	I'll post the address and phone number tomorrow after I go
    home and look it up.
    						/Glenn Tremblay
    

	I imagine this is the same place mentioned in the previous
	reply. The name of their store is "Energy Conservation and
	Solar Center." You may have heard of it refered to as the
	"Kalwall" store. It's at 
				121 Valley Street
				Manchester, N.H.
				(603) 625-9677

	Probably one of the best sources for solar supplies in the
	area.

	-Bob B.

    RE:.3,.4
    		First off, the place is *definitely* not "Energy
    Conservation and Solar Center" that I was talking about. Its
    called "Solar Components Corp" and I forgot to bring in the
    address. I'll post it tomorrow. BTW, they advertise in the back
    of most Homeowner type magazines.
    
    Secondly, if I understand you correctly (note poster) you
    don't want "thermostatically controlled switches" (re:.3)
    
    						/Glenn
    

    Here is the name of the place I promised. Be aware that this place
    is not cheap, but its not unreasonable. I use it more as a reference
    as to what's available in the field. I have purchased several things
    from them though, and they've been very prompt with my orders. 
    
    	Solar Componets Corporation
    	P.O. Box 237
    	Manchester, N.H. 03105
    	(603)668-8186
    
    I don't know how much you should send them for a catalog. The add
    I responded to asked for $2.00 for their catalog, but when I received
    it it was marked $3.00. Don't you just love marketing!
    
    	My apologies to the previous posting that said the place was
    called "Energy Conservation and Solar Center." They were correct.
    That's the name their store goes by! Ooops. So, if you want to 
    visit them, here's there address,
    
    		Energy Conservation and Solar Center
    		121 Valley St.
    		Manchester, N.H. 
    		(603) 625-9677
    
    (At the corner of Pine St. and Valley St.)
    
    						/Glenn
    
                             

    I bought 2 low flow shower heads from them for something like $9
    each, and have been getting their catalog in the mail for a few
    years now for free! They ask if you want to be put on their mailing
    list if I remember correctly.
    
    Jean

    I have just installed an inground pool in Rochester, N.Y.  Although
    our summers are fairly warm these days, and I have a solar cover,
    the water is only about 76 degrees. I have a south facing black
    garage roof that is about 6 feet above the filter. I'm wondering
    if I should put in somekind of solar system maybe with temperature
    sensors and automatic diverter valve to warm the water. Has anyone
    out there done this or seen any articles on the subject????

There's been a bunch of discussion on this, but to my surprise there's no 
specific note in the directories for it.  I guess the current stuff is buried 
in other notes.

Paul

    You wanna raise the temp?  You want a bathtub?  
    
    The open ocean in the vicinity of Bath, ME is 53 degrees.  Now THAT
    could use some help!
    
    :-)

    My fiance's parents in Florida have a solar heater for their pool
    -- for them it's the only thing they need, but that's Florida, after
    all!  (The pool was 86 degrees, as I recall, on Christmas eve a
    couple of years ago when we were visiting...)
    
    Anyhow, their's was just installed, I think they said, by their pool
    contractor. So the units exist, and maybe just phoning some pool
    folks will give you the info you need.  I know their's wasn't custom
    or anything.
    
    Happy splashing!
    
    Sherry

    check out Solar Components 1-800-258-3072
    Call that number and ask for a catalog.
    They carry all kinds of solar goodies.
    

    
    The number you have reached...
    
    		2 - 5 - 8 - - 3 - 0 - 7 - 2
    
    has been changed. The new number is...
    
    		6 - 0 - 3 - - 6 - 6 - 8 - - 8 - 1 - 8 - 6
    
    Please make a note of it!

    Thanks I just got their catalogue they have something called solar
    roll....think I'll order the book on it and price it out. I wonder
    if there's a do it yourself article out there in some magazine like
    workbench??

    	Although the roof sounds like where this will wind up, there may
    be advantages to placing the solar panel at on elevation lower than the
    pool (if possible). Water has properties similar to air in that in a 
    body of water, hot water rises and cold water sinks.
    
    	If you can place the solar collector at an elevation below the pool
    you may be able to get away without having to use a pump (thermo-
    syphoning). If you can do this, you may be able to eliminate the need 
    for electricity and there would be no moving parts. 
    
    	I'm not sure if the flow volumes would be sufficient for a pool, but 
    it may be something worth looking into.
    	
    	Ray

    We had solar collectors on our roof for a pool in California.
    It was hooked into the filter system.  Put a valve one way and
    the water went from pool to filter to solar collectors and back 
    to the pool.  Flip the valve and the water just went from the pool
    to filter and back to pool.  In theory it doesn't use any additional
    electricity - you have to run the filter anyways.
    
    Important to be able to bypass the solar though, at least in
    California ... when the pool reaches 102 degrees, it's time
    to stop heating it ... great for swimming on cool nights though.
    
    Janice (who sometimes misses California)
    
    p.s. You'd want to check into what affect heavy snow loads and
    freezing would have on the solar panels, unless you plan on
    removing them every year.

    re:Using pool filter
    
    	Sounds like a good idea. Just out of curiousity, did some sort of
    regulator or timer need to be installed to adjust the flow through the
    solar panels ? I was thinking that if the flow were too high, the water
    wouldn't stay in the collectors long enough to get optimum heat transfer. 
    
    	Obviously, the solar collectors would need to be drained in the
    winter to avoid breaking the pipes. One other thought. Painting the 
    pipes to/from the collector a dark color (i.e. flat black) would probably 
    add to the total effect too.
    
    	Ray

    
.9>  ...I was thinking that if the flow were too high, the water
.9>  wouldn't stay in the collectors long enough to get optimum heat transfer. 
    
    It's not intuitive, but the optimum heat transfer is attained by
    getting the water through the panel as quickly as possible. The
    efficiency of heat transfer is proportional to the temperature
    difference between the source (panel) and the sink (water). The longer
    the water stays in the panel, and the warmer it gets, the lower the
    temp difference and the less absolute heat is transferred to the water.
    

re: .8

> ... when the pool reaches 102 degrees, it's time to stop heating it ...

A New Englander's dream, without a doubt.

    re:10
    	
    	You're right, it's not intuitive. When you think about passing your
    finger (sink) over an open flame (source), if you move it fast enough, it 
    doesn't even get noticably warmer. I would have also thought too fast a 
    flow would actually reduce the inside panel temperature, resulting in a
    minimal temperature difference between source and sink. 
    
    re:102 degree pool
    
    	That's what a jacuzzi is for. My out-laws have a pool in Va. that
    hits 90 in the summer. Sure, you can jump right in, but after a minute
    or so you find it isn't very refreshing. If you're trying to get relief 
    from the heat, you wouldn't want anything too much above 85.
    
    	Ray

re candle and finger in flame:

To get the most amount of heat into an object (a finger or quantity of water)
you leave it in contact with the heat source as long as possible.  But
the object isn't to heat a small unit of water, it's to heat the whole pool.
If you have water going through the collector at high speed you heat a whole
bunch of "units" of water slightly rather than a smaller units more.  Since
the rate of heat absorbtion is proportional to temp. difference, to increase
heat transfer you make the temp. differential as large as possible.  This
can be done by increasing the temp. of the heat source or getting the already
heated water out of there to make way for colder water.  Thus a high flow rate.

-Mike