I had my new SHW system installed yesterday. It was done under the QLD gov scheme (three days before the fedral gov annouced they were reducing the rebate which the qld gov scheme relied on but looks like i'm in the clear and will get the full rebate). Anyway, the system is a 30 tube evacuated tube split system. It replaces my aged electric system. It still worked fine but probably would need replacing in the next 5 years so now was a good time to jump to it. Out of pocket it cost be about $900 i think. The full system cost was somewhere in the $3000+ range. Here some before and after shots:
The old tank:
The new tank:
For the amount of pipework and cabling etc, i thought it looked pretty clean. I need to pretty up the electrical cabling a little with some conduit as it's too exposed for my liking. I've also had to put some barriers up as the dog chewed up some bits and pieces of the old one when we first moved in. Dont want that happening again.
Some before and after shots of the collectors:
The roof area
The frame and manifold:
The heat pipes installed:
The heat pipes are sealed and simply plug into the manifold. The tubes are made of something like Pyrex glass. Are evacuated and inside there is another tube that has the heat transfer liquid or gas. There's two sensors; one in the bottom of the tank and one on the collectors. If the water needs heating, the controller checks if the collectors are 6 deg C above the tank temp and starts pumping the water through the manifold. If not then it uses the mains booster to heat it. We currently have the night rate tariff (12am to 7am) so it will only boost between those times. I have a remote boost switch in the laundry which allows me to turn off the boost completely and that's how it will be a much as possible. There is also an airvent on the outlet of the manifold that is supposed to reduce any gurgling from the system.
At about 3:30pm on install day the roof sensor read 140 deg C. At 8:30am the next day it was 120 deg C
We had no hot water obviously the night of install and I left the boost switch on to boost overnight. I got up at 3:30am to put the cat away and saw the boost light was not on. My first thought was a wiring problem. I checked the meter box and the night rate controller was in the ON position, but I found the HW mains breaker was still OFF. The installers had unfortunately forgotten to switch it back on when leaving. The few hours from then to waking up did the trick and we have hot water.
Some close ups of the plumbing and the controller:
EDIT: 15 March 2010 - After weeks of rain and a few sunny days I discovered the system was not actually working properly. Two sunny days in a row would see roof temps of 150 deg C and inlet and return pipes that were cool to the touch. The problem was that the pump was in backwards. Strange that there were no direction arrows on the pump but at least it was an easy fix. A colleague loaned me some temp sensor loggers and after the fix here is the data log. BLUE is the solar water return from the collector and the RED is the feed from the inlet to the roof.
