Solar collectors(metal and fabrication content)

On Mon, 16 Feb 2004 23:11:41 -0500, "AndrewV" wrote: ...

I could dig up pictures, but I wouldn't suggest anyone copy them. My particular system evolved by chance from an Ergomax exchanger that was damaged in shipment. If I was starting with an empty CAD file, lots of things would change. For instance, I used their copper coil unit for my output side. It would have been almost impossible to pair my newly formed input tubing alongside their already formed coils. If I was forming both sides, I'd want them as closely coupled as possible, to maximize the heat transfer when I'm using hot water while one or more heat soruces are running.

The dead tank is about 65 gallons, which is what was left after I cut open the Ergomax. That is a nice size for saving enough solar heat for a couple of showers in the evening, or keeping the hydronic floor warm for a couple of hours after the fire in the wood boiler dies, yet it isn't so huge that it takes hours to come up to temperature if it cools off.

I'd like to add a separate ~500 gallon tank and a pump to move the "dead" water between the two tanks. Only work on heating the big tank once immediate needs are met and the small tank is hot. If your main exchanger coils are in a 400 gallon tank and it has cooled off, it will be a long time before you can take a shower!

Oh! You're building a pre-heat system, not your only source of DHW. Guess that bypasses my concerns about the big tank, and the coupling of exchanger coils. The main concerns I see for pre-heat would be being able to bypass the pre-heat when the big tank isn't warm, and keeping the boiler temperature in its safe range.

If you have an iron boiler, it may be running a lot of its water around in a very hot loop, and only bringing in a small proportion of cold water to be heated. You'd want to put your pre-heat exchanger in only this cold stream, not in the main boiler loop. That would also let you use fewer/smaller tubing circuits in your exchanger without restricting your pump flow so much.

Before you mess with your boiler system, I suggest you read this Dan Holohan forum for a few weeks:

Much the same flavor as rcm, but all about hot water heating.

Loren

Yabbut........then the 'collector' has to transfer the energy to the working fluid. It is still 'solar' energy.

Irrelevent. Heat is transfered by radiation, convection and conduction. Whether it's solar, fire or nuclear is irrelevent. Only the nature of the transfer matters. Inside the tube, radiation will be neglegable, convection (the fluid is moving) small and conduction the major factor. You don't want to put any poor conductors in the way.

Ted

Obviously he is concerned with transferring the collected heat into the water. Go drink some coffee.