29 April 2010: Sorry if this is just a list... but it's useful for the progress record:
- Sunbox2 PV: The photovoltaic panel with the crazed glass now has aluminium framing all round the edge and a 4mm polycarbonate over sheet. Much heavier now, but safer, and waterproof.
- Sunbox2 construction: Work has started on the aluminium sections for Sunbox 2, all drilling being done by the Makita drill. But I hope to get a new chuck for the desktop press drill tomorrow.
- Electrical: I want my relays to be able to turn the loftpump Off when the GSHP is in a heating cycle, and after asking around a bit and of testing, I discovered that the Omron relays I already have are dual purpose, they can be in Normally On mode or Normally Closed. i.e. when they come on, they can turn something else off. So I am buying two more relays for use in the loft.
- Datalogging: I have begun to string more wires down from the loft area to the utility room, to turn relays on and off and it's getting worrying how many wires there now are. The Datalogging wires add to the visual confusion of course. I will have to get some more cable ducting to put it all into.
- Pump performance: I have been wondering if the external pump that pushes water round the underfloor system is necessary. It is just above the GSHP and uses 130 Watts at slowest speed and runs most of the time. It would use 3kWh/day just for that pump if left on 24 hrs. I consulted the manual, but it does seem necessary. The under floor system is using very small gauge pipes, and two manifolds, and the pump is necessary for monitoring the current floor temperature. The one inside the heatpump only comes on when actual heating is required.