re: heating system sources
15 mar 1997
randy nelson wrote:
>could someone tell me a web page or other catalog that lists liquid
>and air heating solar heating systems?
commercial plastic film greenhouses make fine inexpensive air heaters that can
also add floorspace to houses in the form of lean-to sunspaces, from local
greenhouse suppliers, or national ones with fine catalogs like stuppy at
(800) 877-5025 in kansas city or e. c. geiger (http//www.hortnet.com/ecgeiger)
(800) 4 geiger, near philadelphia.
people often fill up their sunspaces with thermal mass, with slate floors and
masonry walls and drums full of water, which cripples their solar house
heating performance--low thermal mass sunspaces that get cold at night make
the most efficient solar house heaters.
standard greenhouse curved galvanized pipes on 4' centers (24' long pipes
cost about $35 each) are normally covered with large pieces of cloudyish
polyethylene film with uv-protection, costing 5 cents per square foot, with
a 4 year guarantee. if the film is covered with greenhouse shadecloth in
summer, it should last a lot longer. two layers of film are normally inflated
with a 100 watt blower to prevent wind fatigue. another way to avoid wind
fatigue is to use one layer of film with some nylon rope stretched over the
film between bows. an optically clear (and less private, and longer lifetime)
alternative glazing is replex polycarbonate plastic ($1.25/ft^2 in 49" x 50'
rolls from bob rimol at (603) 425-6563, altho it is much more expensive, and
needs to be attached to every pipe, vs a 24' wide roll of polyethylene film.
(anyone know where to buy wide rolls of vinyl?)
curved bows can also be made less expensively from 1x3s soaked in water
for a few days and bent to shape, eg 2 $1 12' 1x3s bent to an 8' radius,
held together with 1x3 spacer blocks and deck screws every 2'. (i made
a number of these without soaking and snapped about 30% of the 1x3s.)
after the house is 100% solar-heated, some bare hydronic collectors (like
big fins from zomeworks) inside the sunspace might provide hot water, with
a thermosyphoning loop to a conventional water heater upstairs, without any
insulation, pumps, heat exchangers or antifreeze, if the sunspace is kept
above freezing on cold nights.
>i checked out the solar depot but found most of it pretaining to either
>solar or wind generated electricity.
it's strange to see so many people interested in solar electricity, when
(1) heating is a much larger part of their energy budget, and (2) the amount
of electrical power consumption is shrinking, as people use more cfs, etc,
and (3) the cost per kwh may decrease with deregulation and cogeneration.