Hi Mike and All,
Yes, my thought was a parabolic reflector with a black iron pipe along the focal plane. This arrangement is my preferred layout for intermediate temperatures, laying between "solar water heater" and the "burn most anything" temps of a satellite dish concentrator.
No, I have not built one. So far it's only in my head, but I wanted to provide food for thought to the Group members.
Other questions / thoughts to go along with the project:
* If someone had a propane fridge and a non-contact infrared thermometer, what is the temp of the working fluid after it is heated by the flame? The temp would have to be read sufficiently far from the heat source to discount conduction along the tube as a source of inaccuracy. That data would be key to creating the alternate heat source, and it would drive most of the other design characteristics of the system.
* Propane fridges for campers often have a facility of running off of 110v or even 12v. This is effected by a heating element, which is simply held in contact with the heated section of tubing for the working fluid. Could you take a piece of steel bar stock the same diameter as the heated tube section, and use it as a die to form a contacting surface into copper tubing, which would carry the hot oil to the heated tube? That way you have a *surface area* conducting heat, not just a line of contact between two round tubes. Perhaps a copper tube that is larger in diameter than the heated pipe for the working fluid would take the "molding process" better, being deformed by a body of smaller cross-section.
The heat conduction method into the working fluid is worthy of study if the general concept proves feasible. The potential for thermal inefficiency is high where the heat source is applied.
TW
--- In wastewatts@yahoogroups.com, hillwizard2@... wrote:
>
> Hi TW
>
> Parabolic Trough? are you talking about a reflector heating a black iron
> pipe filled with oil?
>
> are you going to build your own?
>
> I don't know the BTU's required, but solar does provide the temperature
> you need
>
>
> Mike the Hillwizard
>
>
> Some people march to a different drummer, I march to the counter beat,
> sometimes pounding out my own tune, and dancing to that.
>
>
> In a message dated 7/8/2011 3:21:54 A.M. US Mountain Standard Time,
> todd_a_wortmann@... writes:
>
> Hi Everyone,
>
> Just musing about my propane fridge, and wondered about a solar heated
> alternative to propane. It would be interesting to find if a parabolic trough
> heating up motor oil would be a good supplement or replacement heat
> source. My old Dometic uses about 1100 BTU/hr, which is barely more than a pilot
> light. Plenty of that heat going up and out the stack.
>
> Does anyone have BTU data from a "size X" trough, which can be used to
> plan an appropriate size trough to replace the propane flame?
>
> Another interesting thought would be to have a highly insulated storage
> tank of, say, 15 or 20 gallons. An oversized trough creates a surplus of hot
> oil, which could be circulated after loss of sun to keep the fridge cold
> through the night. The hot oil storage might be impractical for making
> steam to generate electricity, but a small scale demand like a fridge might be
> do-able.
>
> No, I have not done calculations on BTU storage and oil temperatures -
> this is just a thought at the moment. Someone said in a recent post that they
> can't make propane for their fridge, but you could make plenty of hot oil.
>
> TW
>
No comments:
Post a Comment