DIY Solar Concentrator: Difference between revisions
Jump to navigation
Jump to search
| (3 intermediate revisions by 2 users not shown) | |||
| Line 1: | Line 1: | ||
=Existing Open Source Designs= | |||
==OSE France's Design== | |||
*Whats the deal with OSE France's main page, http://www.opensourceecologie.org/ ? As of 2/17/19 ~19:20 it appears to be down | |||
*[https://www.instructables.com/id/Solar-OSE-Solar-concentrator-for-steam-generation/ The instructable for this] | |||
=Parabolic Tube= | =Parabolic Tube= | ||
*http://www.ffwdm.com/solar/solar-index.htm - $110 USD per kW of heat? | *http://www.ffwdm.com/solar/solar-index.htm - $110 USD per kW of heat? | ||
| Line 14: | Line 19: | ||
*We need T to be 1.3x this | *We need T to be 1.3x this | ||
*We need 482K, or 1.33x this K | *We need 482K, or 1.33x this K | ||
*1.33^4 = 3.1 - so only 3x concentration is needed | *1.33^4 = 3.1 - so only 3x concentration is needed if there were no other losses | ||
*Convective loss calculator - [https://www.engineersedge.com/heat_transfer/convection.htm] | |||
=Links= | =Links= | ||
*Paper on Medium Temperature Concentrators - overview for tech up to 250C. We need 200C for saturated water. [https://academic.oup.com/ijlct/article/9/3/214/808795#14051557] | *Paper on Medium Temperature Concentrators - overview for tech up to 250C. We need 200C for saturated water. [https://academic.oup.com/ijlct/article/9/3/214/808795#14051557] | ||
Latest revision as of 19:51, 17 February 2019
Existing Open Source Designs
OSE France's Design
- Whats the deal with OSE France's main page, http://www.opensourceecologie.org/ ? As of 2/17/19 ~19:20 it appears to be down
- The instructable for this
Parabolic Tube
- http://www.ffwdm.com/solar/solar-index.htm - $110 USD per kW of heat?
- But this requires replacement of insides with a u- copper tube, which is a valiant effort. Tbis is because evacuated tubes have a closed heat exchanger mechanism - a closed copper tube with heat exchanger bulb.
- Unless one can find low cost u-tube heat exchangers, the evacuated system appears to be too complicated compared to plain black tubes.
- Does not appear highly relevant to saturated water storage.
BOM
- $25 per 6 foot evacuated Tube, no inner tube - water directly in glass? - [1] - affordable.
Calculations
- Max T that a metal can get when in full sun in 90C - see nice explanation at [2] combined with Stefan Boltzmann constant - [3]
- So we see that the max temp in K varies as the 4th root of power density hitting the object. For example, to double the temp in K, need 16x solar concentration.
- 90C = 363K. Double to 726K - max 450C.
- At this point, conduction and convection play a good role.
- We need T to be 1.3x this
- We need 482K, or 1.33x this K
- 1.33^4 = 3.1 - so only 3x concentration is needed if there were no other losses
- Convective loss calculator - [4]
Links
- Paper on Medium Temperature Concentrators - overview for tech up to 250C. We need 200C for saturated water. [5]