????????? For Solar Gary

[mdharris68]

Solar Gary,

Do you have a formula for figuring a passive solar greenhouse load? One of the walls will be a common wall with the house. We are planning on using black barrels full of water as a storage medium. Do you have any links to useful guidlines for this type of heat storage? I am just wondering if there is a way to figure this out other than trial and error? Thanks for any help you can provide.

[WisJim]

A good book on passive solar heating or solar greenhouses should have the information that you want--how to figure heat losses and solar gains, amount of storage of various kinds for glass area, etc. Offhand I don't recall titles, and my bookshelves aren't handy at the moment.

[mdharris68]

Thanks, I'll do a search on passive heating loads.

[SolarGary]

Originally Posted by mdharris68

Solar Gary,

Do you have a formula for figuring a passive solar greenhouse load? One of the walls will be a common wall with the house. We are planning on using black barrels full of water as a storage medium. Do you have any links to useful guidlines for this type of heat storage? I am just wondering if there is a way to figure this out other than trial and error? Thanks for any help you can provide.

Hi,
I thought I posted a reply yesterday, but it looks like it did not make it.

All my knowledge on greenhouses is from books, so there may be others here with much better advice.

The main recommendation I'd make is to get a copy of this book:
The Homeowner's Complete Handbook For Add- On Solar Greenhouses and Sunspaces
Andrew Shapiro
Its out of print, but you can get if from places like amazon.com in the used books area for about $8 -- a real steal!


There are a lot of ins and outs to greenhouse design depending on whether you want to heat your house or grow plants and what your climate is.
I think you want to grow plants?

The book is very good in that it gives design charts for green houses and sunspaces that cover sizing and orientation of glazing, thermal mass, ...
and, it provides this info for several different climates.

I guess the general rules for solar greenhouses would be: glaze the south facing walls and roof, insulate all the surfaces not facing south, insulate the floor in some way, provide the right amount of thermal mass (see the book), seal it up well, but provide for ample summer ventilation.
In cold climates, double glazing (maybe the two poly walls with the blower inflating the space between), and some form of night insulation for the glazing (maybe bubble wrap?) will all be good to reduce heating requirements on cold nights.

I've accumulated a bunch of greenhouse design info and plans here:
http://www.builditsolar.com/Projects.../sunspaces.htm

If you want something out on the cutting edge, search down for "solar bubble build" -- a pretty neat idea (I think).

Gary

[greg273]

Solar Gary,

I've had that book for years now, and never get tired of reading it!...hopefully this spring I will begin work on my own, using mostly 'recycled' patio doors from the local door/window manufacturer. Seems everytime they install new doors, the old ones are brought back to the shop to be ... get this.... burned, with the glass smashed out thrown away, and what little aluminum left is recycled. Oftentimes I can go down and get a truckload of these free for the hauling, if I happen to catch them before they get burned. (oh, and I did ask permission first... seems I'm doing them a favor!)

These doors usually have double-thickness tempered glass, heavy and durable stuff.

Best of luck!

[mdharris68]

Thanks to all for info provided. I found a neat way to heat greenhouse with a solar collector and underfloor water storage on one of Solar Gary's links.

Also found one persons idea for figuring amount of passive collection. I will have to go back and get the link later, but the figure was this: For every square foot of glazing, it takes 2 gallons of water or 80 lbs. of rock to absorb enough sun to store and radiate back at night.