Step 9: Testing
I rigged up a test circuit to see if my master plan had worked. It was a 5 gallon bucket with an inlet at the bottom and an outlet at the top. I hooked the outlet (top end) of the collector to the inlet (bottom end) of the bucket using a garden hose. I hooked the other two ports up the same way.
The idea:
Heated water moves up the coil and through the hose into the bottom of the bucket. The same water then rises in the cooler temperature water bucket and is recirculated back to the coil out the top port of the bucket to the lower end of the collector. Hopefully that process repeats.
Results:
It worked! for awhile... The heated water began to soften the garden hoses so much they collapsed under any bend radius at all.
Before they collapsed I added food coloring that shows the water circulating and being pulled back into the circuit. Then all of a sudden everything stopped. I used my infrared thermometer and checked my outlet temp at the box and got a reading of ~250 degrees F... I thought this couldn't be right so I used a few other thermometers and got similar results...
Conclusion:
I think the water in the coil may have vaporized and turned to steam (water boils at 212 F) which caused a vapor lock and halted my circuit flow. Over all I'm happy, better plumbing setup and less hasty testing will really tell me how well this thing works, but for now I'm satisfied.
Note:
The collector works very well, during dis-assembly of my test rig I ended up draining the coil onto my hand and burned myself pretty significantly. Blisters and the whole deal. just a heads up, be careful.
Anyhow, this was the build and a tid-bit on the testing. I'll come back through here some day and go into more detail so if someone wants to build one they can improve off what I've done.
Thanks for reading.
Feel free to shoot me questions if I've completely skipped something you want/need.
The idea:
Heated water moves up the coil and through the hose into the bottom of the bucket. The same water then rises in the cooler temperature water bucket and is recirculated back to the coil out the top port of the bucket to the lower end of the collector. Hopefully that process repeats.
Results:
It worked! for awhile... The heated water began to soften the garden hoses so much they collapsed under any bend radius at all.
Before they collapsed I added food coloring that shows the water circulating and being pulled back into the circuit. Then all of a sudden everything stopped. I used my infrared thermometer and checked my outlet temp at the box and got a reading of ~250 degrees F... I thought this couldn't be right so I used a few other thermometers and got similar results...
Conclusion:
I think the water in the coil may have vaporized and turned to steam (water boils at 212 F) which caused a vapor lock and halted my circuit flow. Over all I'm happy, better plumbing setup and less hasty testing will really tell me how well this thing works, but for now I'm satisfied.
Note:
The collector works very well, during dis-assembly of my test rig I ended up draining the coil onto my hand and burned myself pretty significantly. Blisters and the whole deal. just a heads up, be careful.
Anyhow, this was the build and a tid-bit on the testing. I'll come back through here some day and go into more detail so if someone wants to build one they can improve off what I've done.
Thanks for reading.
Feel free to shoot me questions if I've completely skipped something you want/need.
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One quick question tho: wouldn't it be more effective to connect inlet of the collector with an outlet at the bottom of bucket and outlet of collector in the top of bucket? this way, when rising the bucket a little higher than the collector, natural circulation should do the work. And also, due to the fact that you would take the cold(er) water from the bottom of the bucket to be heated, it should prevent the problem with the vapor lock (well, at least til the whole bucketfull is boiling :) ?
You might be correct, I think there are likely a number of things that could be improved during testing. Your idea is probably the first place to start.
I still have the the collector sitting in my garage, maybe some day ill pull it out and do some more testing.
Again, thanks for the feedback!
If you look at the edge of a piece of glass and it is a light green color, the glass contains some iron. The iron cuts down on the suns heat transmission. Clear glass lets the infared thru. Also when you seal the glass to the wood box , eventually you will get moisture trapped in the box.
While studying the coverings for collectors several years ago I found that Visqueen (trade name) plastic sheeting allowed more of the desireable infared rays into the collector. I used 6 mil thick sheeting. An added benefit was that the collector needed to be cleaned of dust periodically. The plastic sheeting was cheap and replaced when the dust was cleaned out..
Now that you have constructed a collector capable of producing steam, carry your experiments a little farther. Absorbtion refrigeration systems work on heat. An example is refrigerators in campers operating on propane.
At one time Absorbion refrigeration was popular in the south for airconditioning homes. Industrial plants use large absorbtion systems operating on steam to cool their office spaces. Carrier makes 100, 200, and 300 ton units. Several companies made units for homes. Bryant, Arkala, Servel, and two others were popular brands. Their airconditioning units worked fine. Their problem was in the servicing. The units were sold thru Natural Gas and Propane suppliers and their heating techs didn't know how to service the absorbtion systems. I attended a very large Solar Expo in Phoenix several years ago and the Japanese had absorbtion units on display that operated on solar collectors. Google Absorbtion Refrigeration to find out more.
You are to be commended for your achievements. The Instructable is well written and your pictures are clear and informative.
As for the covering: there are definitely better light transmitters out there. I was limited to what was on the shelf (built and tested in less than two days) I chose glass over plexi for light transmission and for it's durability to the sun. Plastics will often break down very quickly under UV exposure. Not sure how the Visqueen is UV rated.
Sealing the box: hindsight is 20/20 on that one. As you can see in the test photos the moisture trapped inside the box condensed on the glass covering. It was interesting to watch- the second I turned on the water hose and allowed cold water to flow through the coil the heat was immediately sucked out of the air in the box and the condensation was completely gone. It was a physics/thermo experiment all it's own.