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Cor Stijgers

Jan 1, 1970
0
Hi Adam,

I like your pictures very much!

I understand that you may have some experience with heating the house on
solar energy?

I'm considering to heat my future home on solar power, but I can not
find much information on the Internet on heating. Most of the
information is about heating tapwater. We do not use much hot tapwater,
so we don't expect serious savings there.

I wonder how many square meters solar collectors are needed and
how many liters storage for the hot water. Do you have any experience on
this, or do you know where I can get some information?

kind regards
Cor Stijgers, Amsterdam
[email protected]
 
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Ecnerwal

Jan 1, 1970
0
Cor Stijgers said:
I'm considering to heat my future home on solar power, but I can not
find much information on the Internet on heating. Most of the
information is about heating tapwater. We do not use much hot tapwater,
so we don't expect serious savings there.

I wonder how many square meters solar collectors are needed and
how many liters storage for the hot water.

This question is a great deal like asking "How long is a piece of
string?"

With no information about where the house is, what size it is, what the
incoming sun resouce is, the local climate, the specific values of
insulation, it's quite impossible to say how many square meters of solar
collector you need, or how much hot water storage you need.

In a mild climate - less. In a harsh climate - more. Few cloudy days in
a row - less. Many cloudy days in a row - more. Well insulated - less.
Poorly insulated - more.
do you know where I can get some information?

alt.solar.thermal - read the archives for a lot of solar house heating
background information, then post some specifics about your house design
and house site. I'm guessing, since you asked about square meters of
collector, that we'll need to try to recall what the European R-values
for insulation actually refer to, since most regulars on that group are
using US R-values based on imperial units and will need to convert to
consider your design, and I'm not recalling what the underlying units
for the metric version of the same number are.
 
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Nick Pine

Jan 1, 1970
0
Simple sunspaces are cheaper than "solar collectors."
With no information about where the house is, what size it is, what the
incoming sun resouce is, the local climate, the specific values of
insulation, it's quite impossible to say how many square meters of solar
collector you need, or how much hot water storage you need.

We can make things up... If 3 kWh/m^2 of sun falls on a south wall on an
average 0 C day and the 20 C house has 50 W/C (284 Btu/h-F) of conductance,
it needs 24h(20-0)50 = 24K kWh/day (82K Btu/day) of heat. If a square meter
of U2.8 (US U0.5) sunspace glazing with 80% solar transmission collects
2.4 kWh over 6 hours on an average day and loses 6h(20-0)1m^2xU2.8 = 336 Wh,
for a net gain of about 2 kWh, the sunspace needs about 24K/2 = 12 m^2 (129
ft^2) of glazing. If we needs 5x24 = 120 kWh for 5 cloudy days in a row and
a liter of water releases 1.16Wh/kgC(70-20) = 58 Wh as it cools from 70 to
20 C, the house needs 120K/58 = 2069 liters of cloudy day storage.
...we'll need to try to recall what the European R-values for insulation
actually refer to...

R-values are measured in W/mC, conductance is measured in mC/W, and
US R5.68 (Btu/h-F) becomes European U1 (W/C.)

Nick
 
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News

Jan 1, 1970
0
Cor Stijgers said:
Hi Adam,

I like your pictures very much!

I understand that you may have some experience with heating the house on
solar energy?

I'm considering to heat my future home on solar power, but I can not
find much information on the Internet on heating. Most of the
information is about heating tapwater. We do not use much hot tapwater,
so we don't expect serious savings there.

I wonder how many square meters solar collectors are needed and
how many liters storage for the hot water. Do you have any experience on
this, or do you know where I can get some information?

If you want to heat your house using solar energy, using a wet system, it is
best to use a low temperature operation underfloor heating system. Using
low temperature operation mean that even in winter you may be able to use
low temperature hot water effectively. Have the roof panels, or better the
whole of the south side of the roof, heat a large thermal store cylinder.
The lower section of the thermals store should be used to heat the
underfloor pipes, with the top section to heat the domestic hot water - if
there is not enough high temperature heat for domestic hot water
supplementary heating can heat just the top section. The thermal store
should be sized to give 3-4 days of heat in cloudy conditions if possible,
depending on climate of course.
 
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News

Jan 1, 1970
0
I used to have a solar-assisted home in Colorado.
I had ten panels on the roof, I think they were 3x5 each. There was a
400 gallon water tank in the basement. Because of freezing weather, I
used an anti-freeze solution in the panel loop. Instead of an
expensive heat exchanger, we used about 150 feet of flexible copper
pipe coiled in a loop, which was in the lower part of the water tank.
This pulled the maximum heat from the loop. Another similar loop in
the upper part of the water tank pulled heat out for pre-heating the
domestic water.

To heat the house, water in the tank was pumped into some heat
exchangers in a forced-air system.

Heat exchangers for forced air systems require high temperatures, otherwise
draughts occur. That is why low temp underfloor heating is ideal for this
application. How did it manage with the forced air?
For home heating backup, we had a
gas-fired flash heater, by Aquastar.

Typically in winter, our gas bills were under $25, and part of that
was an account charge. Similar houses ran about 80 dollars per month,
I am told.

Was yours $25 per month?
 
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