boiler insulation

[Ed_Dinning]

Hi Ted, thanks for the info, I will be working on similar lines, probably using |LM35's as temp sensors.
It will be a home made collector from some surplus copper pipe as well as thin sheet to aid collection. I have a tank already so I will fit a coil into the base via a sweated plate on the side at the bottom (3" * 1/4" busbar, ).

Off to Oz tomorrow to escape the winter, might get a start on this project on my return, plus some ideas for the people down under.

Ed

Ed, regarding Solar heating The wife and I made our own 28 years ago and it failed once. We made fibre glass tray, in which we mounted domestic radiators, painted mat black. We made a mould in ply wood with reliefs all round to facilitate tray extraction. We based the tray size on Horticultural glass as used in green houses, so they were each approx 30x 54 inches in size. We bought a cylinder to our own design as they were only made to order those days by IMI Leeds or Hull. We wanted a cylinder with two coils, the lower one to have a surface area twice as large as the top one, which was a standard gas boiler size. The cylinder was about 5 feet tall by 18 diameter, with two extra inlet or outlets. We used a normal domestic circulator as a pump, to circulate anti freeze and inhibitor around the system. We piped it up ourselves using 22mm copper all round.Basically we used a two pipe manifold system, nothing complicated at all. We used a small make up water tank to create a head of water.When we were assembling the panels we mounted two Thermisters on each panel using Aradite, the Thermistor were connected via screened cable back to the control box. Another Thermistor was mounted on the lowest pipe on the Solar coil,again we used screened cable. In the top outlet of the Solar coil we fitted an inline non return valve, I made that easily adjustable as were weren't 100% sure of what was needed. I made a simple controller using a 741 op amp, a BC 107, plug in relay, tiny 240/12 tranformer bridge rec, a bit of smoothing and a zenner.We filled up the system and we were pleased to say it worked straight away and continued for 26 years, with a bit of maintenance when we remembered.We had 3 panels and were more than self sufficent for domestic hot water from mid spring to mid autumn and through out the summer.We had two teenagers and they could stand under the show for long enough and still have hot water. I modified the washing machine to take full advantage of all the hot water available. As the family moved away we thought electrical energy was be coming expensive so removed the system summer 2011 and had PV panels fitted. The rear of our house faces South, so fr the PV panel have given us a good return on our investment.Not sure about helping the earth. I could send you a layout of the system, together with circuit diagram.Ted