Backyard Aquaponics
A place to discuss aquaponics

Ok you may have seen a post in the "Toys" thread showing a Evacuated Tube Solar Array that I've been developing with the assistance of a local manufacturer....

So here's the low-down.... it will run to several pages... so please be patient, and refrain from posting questions and comments until I've posted it in it's entirety... then I'll happily throw it open to all and sundry....

Some months ago I began discussions with a local manufacturer and supplier of evacuated tube solar systems...

The design brief was simple.... give me a solar array system that will raise an average tank of at least 1500ltr capacity to temperatures that enable Silver Perch and Barramundi to survive and if possible eat and thrive through the winter months....

The unit must be stainless steel and not contain the usual copper heat exchangers in the header tank, probes or any other components.

The unit must be capable of being a pumped system, rather than just a (stainless) header tank that works by thermo-siphoning.... preferably controlled by a "set and forget" "intelligent" controller

Must have the ability to program the controller and to operate manually...

Must be relatively low flow and energy efficient in operation...

Our first prototype was duly built... a 48 tube horizontal unit...


And mounted on the roof for trial ...

The trial unit did not include the controller... but was effectively just a blind test...

Pump to array from a tank... heat by the evac tubes and drain to the 1000ltr tank... measure heat gain...

The results over a week of sunny days saw the tank temperature exceeding 35 degrees...

But the pump was running continuously throughout the day and was turned off overnight... and the tank was insulated...

We soon came to realise that used this way.. the power consumption would be excessive... especially with the head involved and the pump sized accordingly...

Several other smaller units were trialled concurrently... with the newly arrived controller incorporated...

A twenty tube array and a ten tube array...

With somewhat mixed results... and some inclement weather... it was decided that I would utilise a 24 tube array (half the 48 tube system, with the opposing holes blanked off)... and continue the testing at home where I could simulate a more realistic scenario...

And monitor and chart results...

The 48 horizontal unit was discounted as being unviable due to size, weight and cost...

And the necessity to mount it on the roof... I really wanted a unit that was "standalone" and could be easily incorporated into most systems... and deactivated or disconnected and stored through summer...

The trial unit was duly delivered two days latter.. complete with a hastily constructed "stand" ...

24 evac 1.8mtr tubes ...

And a stainless steel header..

Pump, Controller, Gaskets, nuts & bolts...

Non-return valve, Relief valve and a ball valve... the latter to become a wise decision...

a 1500ltr tank was setup in the middle of the lawn... deliberately, to simulate a worse case scenario...

Uncovered, uninsulated and unpumped... to determine the starting ambient water temperature... and I began to fill it...

While it was filling the kit stand was laid out and sorted...

And assembly commenced...

Tank was now full... and would be left that way overnight and another day/night to establish a base point...

The kit goin together...

The array base stand completed...

Roughly positioned the base and array support... to check orientation and that everything would reach the tank...

Clipped the tube end retainers into the rail...

Discovered the top rail was missing and had to dummy up something to attach the header tank to..

Measured, aligned and mounted the header tank...

Dragged out boxes of tubes...

Gasket sealers and silcone grease...

Flipped open the tube retainers/tensioners...

Ready to insert the tubes into the header...

Apply the gasket to ensure a good seal and the silicon to ease the tubes in without breaking them...

First couple of tubes in ...

Half done...

All done... clip the retainers down..

Tension up the tubes...

Add another support to replace the missing top rail... not part of the "kit" ...

Attach controller and patch panel...

Quick water proof job... rain threatening...

Relocated the postion of the array.....

Mounted the array on the stand.... don't be fooled... as tough and strong as i may be...

This is definitely not a single person job... don't even try it alone...called a mate around to help...

Looking good..

In position... ready to be plumbed...

Plumbed up the feed line from the fish tank...ball valve below the non-return valve... to adjust flow rate...

Plumbed in the return feed line from the header tank...

Notice the pressure release valve... to vent hot water/steam if it all gets too hot...

Extremely unlikely to occur in this system... and the controller has a high temperature cut off that can be set as required anyway...

But a handy way to adjust the flow rate... if it bubbles out the top... turn the flow down...