Friday, January 9, 2009

Poor control

So I've been collecting data from the temperature monitors for a while now and one thing is abundantly clear.

The air-conditioning controller sucks.

(That would be HVAC for the crazy people that still haven't gone metric yet)

Graph is of room temperature for 4 rooms over the last 24 hours, with the air-conditioner turned on at ~ 1930. Note that it starts cycling almost immediately.

To put it in context, this is an AC that has a variable-speed-drive on the compressor, so there's no reason whatsoever that it should be oscillating. The PID loop driving it (and I do hope there is a PID loop...) should hold it all at a steady state.

(Note that the green line aka Living Room zone was turned off until ~ 2330 which is why it didn't start cycling until then. And the reason that the study isn't cycling more is that the balancing is awful and there's not enough air going to the study. Something I need to climb into the roof space to adjust the dampers for I think.

The AC is a Daikin FDYQ200MR. Which is a 22.2KW system I think. (Note that that's not the power draw: That's the peak heat-pumping capability).

Added to the to-do list: See if I can find datasheets for the AC VFD + compressor + evaporator, and scrap the existing controller in favour of talking to the VFD directly. Task #5412345 I think that is...

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