27 Feb '11: During this Sunday before I go to EcoBuild, I am thinking of what else could be done to improve this system. Well the pipes which leave the sunboxes are well insulated, but there is a question of how much weather and sun the black tape and adhesive can take. So it would be a good idea to build a weather shield for them too - I have enough Aluminium for the job!
So expect a design for this corner soon.
There are also small airgaps around the pipes. Now that I have established the importance of airtightness, it would be worth an investment in some clear Silicon filler for these gaps.