Posted by codechump on December 24, 2008, 9:40 pm
> I haven't seen any mention of a sun tracker,
> though I may have missed it.
> I guess it would be necessary, unless you have a
> slave constantly moving
> the reflector.
> What would they cost, including motors?
> From the discussion it appears that the parabola
> is more cost effective for water heating. How
> would they compare for space heating?
> azuredu wrote:
> > On Dec 24, 4:53 pm, david.willi...@bayman.org (David Williams) wrote:
> >> It depends on how clear the atmosphere is. If it's nice and clear,
> >> there won't be much absorption even if the sun is fairly low in the
> >> sky.
> > Even on a clearest day, the atmosphere absorbs at least 20% of the
> > radiation reaching it when the sun is at zenith. This absorption rate
> > increases rapidly when the sun is near horizon.
You might consider a Hydronic system for heating. That way you could
combine solar and back up from propane if needed. Here's an idea to
get you started:
http://www.solarhaven.org/HPArticle.htm
Also, there are some ingenious mechanical trackers, I've heard of but
not yet seen specs. on. Here's one possible link to a water powered
tracker:
http://www.builditsolar.com/Projects/OddProjects/odd_project_refs.htm
Posted by RF on December 25, 2008, 3:47 am
codechump@gmail.com wrote:
>> I haven't seen any mention of a sun tracker,
>> though I may have missed it.
>> I guess it would be necessary, unless you have a
>> slave constantly moving
>> the reflector.
>>
>> What would they cost, including motors?
>>
>> From the discussion it appears that the parabola
>> is more cost effective for water heating. How
>> would they compare for space heating?
>>
>> azuredu wrote:
>>> On Dec 24, 4:53 pm, david.willi...@bayman.org (David Williams) wrote:
>>>> It depends on how clear the atmosphere is. If it's nice and clear,
>>>> there won't be much absorption even if the sun is fairly low in the
>>>> sky.
>>> Even on a clearest day, the atmosphere absorbs at least 20% of the
>>> radiation reaching it when the sun is at zenith. This absorption rate
>>> increases rapidly when the sun is near horizon.
>
> You might consider a Hydronic system for heating. That way you could
> combine solar and back up from propane if needed. Here's an idea to
> get you started:
> http://www.solarhaven.org/HPArticle.htm
>
> Also, there are some ingenious mechanical trackers, I've heard of but
> not yet seen specs. on. Here's one possible link to a water powered
> tracker:
> http://www.builditsolar.com/Projects/OddProjects/odd_project_refs.htm
>
Thanks CC - the second link is a great resource.
Enjoy the holidays :-)
Posted by azuredu on December 25, 2008, 5:42 am
> I haven't seen any mention of a sun tracker,
> though I may have missed it.
> I guess it would be necessary, unless you have a
> slave constantly moving
> the reflector.
> What would they cost, including motors?
It didn't show in the picture, but I promiss you all the details, with
the schematics and an open source program, in a few weeks. A Chinese
factory is readying a product which will be sold online very soon,
probably for less then 10$ retail price. Of course including the
stepper motor and gears.
> From the discussion it appears that the parabola
> is more cost effective for water heating. How
> would they compare for space heating?
Solar space heating is much harder than water heating, because the
equipment is only used a few months in the year, and these are the
most difficult months of the year. I am afraid that my parabola is the
only solution that can really bring solar space heating cost down to
below that of fossil fuels, especially for high latitude regions.
Details of the economical analysis will come out with all the rest.
The economic criteria for space heating is that the collector should
not cost more than 250$/m^2 installed, and should remain very
efficient during the winter. Oh I've forgotten: I don't count on
government subsidies in the cost analysis.
> though I may have missed it.
> I guess it would be necessary, unless you have a
> slave constantly moving
> the reflector.
> What would they cost, including motors?
> From the discussion it appears that the parabola
> is more cost effective for water heating. How
> would they compare for space heating?
> azuredu wrote:
> > On Dec 24, 4:53 pm, david.willi...@bayman.org (David Williams) wrote:
> >> It depends on how clear the atmosphere is. If it's nice and clear,
> >> there won't be much absorption even if the sun is fairly low in the
> >> sky.
> > Even on a clearest day, the atmosphere absorbs at least 20% of the
> > radiation reaching it when the sun is at zenith. This absorption rate
> > increases rapidly when the sun is near horizon.