Using a dish to track the sun.

collectors

Hi, I hope you can help with a slightly different set up for a sat dish.
We want to use the dish to track the sun using it as a parabolic reflector to concentrate heat onto some piping we have set up for heating hot water. (A little experiment for the green ones) lol.
What we are not sure of is
1. Can this be done? &
2 . what might be the best & most reliable units be for this.
We are assuming that a dish can be set up to be automatically in a certain position for recording programs from different satellites. So we hope to use this facility to track the sun throughout the day & start again the next day.
(Or do you think I might be looking at this the wrong way)

Hope you can help.

Thanks,

Chris.

pedro2000uk

you'd need 150 degrees even at just 1 degree resolution ... not sure if there is a box that will allow so many programmed positions or recorder positions, maybe a pc card or lynux based box. You also need to track the sun's winter to summer positions so you need an incline motor too (36v actuator usually but you can butcher a second diseqc motor and maybe need to use a second box)....

or make your own with stepper motors 1 for arc, 1 for incline angle.

Huevos

You don't want a dish for that. You want a parabola top to bottom and completely flat left to right. That will focus the sun along a piece of horizontal pipe rather than in just one spot. As for a mount just build one yourself. The axis of the mount is north-south parallel to the axis of the earth. I do a bit of astro-photography and I've built quite a few different mounts. My mounts have a rifle scope parallel to the axis which is used to line the mount up on the north celestial pole (using the stars). The mount turns at a linear rate so a stepper motor and a quartz oscillator set up work fine. Elevation change due to the seasons is less than half a degree a day so you could set that manually every few days. How often you need to reset this would depend on the diameter of your tubing.

Turok

Hello!
i only know the egis solar tracker from germany!

best system,on the market!
used worldwide !
but price is very high now i would say new minimum 2000€ included controll box!

**p://egis.org/trac2_de.html

collectors

Hi & thanks for the suggestions. I will certainly look down the earths vertical & horizontal position using astrologers tools. Some of their motorized tracking mounts/tripods look like a very inexpensive way to go. (Like it) So i will have a quick look down this route for possibility's. But any & all suggestions are still more than welcome.

Thanks.

Chris.

collectors

Hi all, many thanks for your suggestions to this problem & all help & suggestions are really appreciated.
Been having a look down the astrological route that Huevos suggested with using astrologers type of equipment to do the job, & see they have some very inexpensive tracking tripods with twin motors set up for all possibilities of tracking objects in the sky.
This looks quite interesting alternative & a lot cheaper than the sat dish alternatives.
I haven’t looked fully at this idea, but seem that a lot of tracking systems seemed to be limited to 40deg or so. Or am I not looking at this correct way for tracking the sun for about 8 to 9 hours a day in the summer months.???.

Thanks.

Chris.

PS, this will be for tracking the sun farther south in France around the 45deg mark.

Huevos

You only really need a single motor. The reason for twin motors is because an ALT/AZ mount is being used. An ALT/AZ mount skews as it tracks so is no good for pictures. For a polar mount to track the sun for 8 hours you need a 120 degree arc. A polar mount can have a complete 360 degree arc, and if you were to want it can turn forever just like a wheel. In your case though the limiting factor would be the plumbing that holds the medium that used for heat transfer from your heated element to your holding vessel.

8 hours of midsummer tracking would be from azimuth 94 (08:00 UTC) to 266 (16:00 UTC). This 172 degrees in azimuth concords with 120 degree on a polar mount.

Personally I wouldn't bother with such a set up. I'd rather a use a large black radiator. Put it in a wooden box with a good 6 inches of rockwool insulation behind it and the double or triple glaze the front face. And then just fix it due south at 53 degrees elevation (53 degrees is the mid point between max midsummer elevation at midday of 68 degrees and elevation of 37 degrees which is the elevation at 08:00 and 16:00).

Turok

Hello!
what kind of astronomic software,is avalible on the market?

and how the backchannel "works",will say,how know the tracker,where the sun is located at the moment,is there any special quitment nesersary?

a solar panel dish,would be nice,to generate power,with a big akkupack,for all electronic devices in the houshold

collectors

Hi Huevos,
Sorry on the delay getting back, it’s that dam think called work. Lol.
On the plumbing part, I would be looking at a form of copper plate with a heat exchanger attached to it.
With the black radiator way of doing things, this was my 1st route. But on reading up on this type of power/water heating it’s apparently around 30% more efficient to track the heat source so that it’s centrally aimed at the collector being heated. But all idea’s can lead to a solution.
With this project we are trying to be a little green & sensible on many things at the same time, but not be silly on spending lots of money on expensive things that won’t benefit us, or take 10 years to recoup the money & find its worn out & out dated by then.

Cheers.

Chris.

Huevos

Nothing to stop you tracking the source with a rad. I think the parabola idea would be inefficient. First the reflective surface needs to be a perfect shape with a mirror finish, and second you aren't going to have much surface area for heat transfer. Also, if you don't put it in an insulated housing you would lose a bunch more heat.

Turok

Hello!
what type of solarpanels you will use for your experiment?
there are so many panel typs on the market,what type is the most effektive for its money?

BUZYONE

hello there
rca electronics in australia make a solar tracker kit that works perfect for what you want it even goes home after dark ready for tomorrow finds holes in clouds which focus sun heat better than through clouds good party trick too.
good luck
buzyone