Ta, it's based on the bigginhill solar design. Hard wood frame, ply back, 2 inches of rockwool followed by a few sheets of aluminium foil(shiny side out) and topped with a 16SWG aluminium sheet with a coil of 10mm copper microbore pipe stitched to the plate with 2mm copper wire. Glazed with 4mm float glass which is half and inch above the top of the microbore. Pressurised the system yesterday and fixed a couple of leaks. Fitted the 20 watt solar panel above the collector this morning and bob`s your uncle.
Today has been sun shine and showers day but the system has still managed to raise my tank from ambient up to nearly 40 degrees and its only just turned 4 in the afternoon.
Nice day today and the water in the tank is too hot to shower in without adding cold. Defo need to add a thermostatic mixing valve to the hot water outlet at the tank or the shower itself to avoid scalding. Also ordered a pump controller which should come tomorrow. Think it will pay for itself in the early mornings and late summer evenings not having the pump running before the collector temp has risen above the tank temp. Fingers crossed.
Went for a £90 job from Peter. It's quite a thing, loads of cracking features. It's defaults are set for an evacuated tube collector so any thoughts on Max tank temp and Emergency Off and On are most welcome for my style of collector. The EMOFF was 130 and EMON was 120 which i though was a bit on the low side??? The default for Max tank temp was 60 which i also thought was a tad on the low side??
max tank temp is typically 60 for immersions etc. if you decide to run higher, and very many people do because it increases your 'thermal battery capacity', you need to think about 1) thermostatic mixing valves anywhere a child, older person, or unsuspecting visitor could get scalded 2) what's the temperature relief setting on your calorifier ? tank temp must sit below this. 3) most immersions have a manual reset temperature cutout
i run my tank at 83c, i.e., heat dump relay triggers at 83 at the base of my tank. i have a thermo mixing valves on the shower and bathroom handbasin. 83c was selected because 85 triggers the manual reset thermal cutout on the immersion heater.
compared with 60c i get an average of 50% increase in energy storage capacity compared with running a tank at 60c, based on a cold water inlet temp of 10c. so it means you can use a smaller tank more efficiently.
Good stuff, thats what i wanted to hear. Going to put mixing valves on all the hot taps i think instead of the outlet to the calorifier that way the washing machine can still have a fill of nice hot water. I don't have an immersion on my tank just twin coils, one solar and one to the stove which also acts as a heat dump loop for tank which kicks in at whatever temp i set into the controller. Mid 80's sounds good. Cheers cye.
..ah.. it's all coming back to me now. i remember now that we had discussed using the stove as a heat dump. the grey matter must be degrading faster than i had thought!
peter's cheaper 12v controller also has a heat dump and freeze protection facility. it just doesn't have the high temp cut off, only has a single deltaT temperature for both pump_on and pump_off, and can only be reprogrammed by linking to a computer. Whereas i think the fancier one you have bought enables separate settings for pump_on and pump_off temp differences? the other advantages with the fancy 12v controller are that it shows you the tank and panel temperatures (you need to plug the cheaper one into a computer to see these readings), and that users can program the various settings themselves.
have you found any other useful features other than the above?