From ad9d08b2a21b06ed1c08f472cd60794f1adb31d8 Mon Sep 17 00:00:00 2001 From: David Woodhouse Date: Fri, 8 Sep 2023 16:54:31 +0100 Subject: [PATCH] Adjust output temp to reduce hysteresis --- pool.yaml | 18 ++++++++++++++++++ 1 file changed, 18 insertions(+) diff --git a/pool.yaml b/pool.yaml index ee43c90..34b3863 100644 --- a/pool.yaml +++ b/pool.yaml @@ -74,6 +74,24 @@ script: // We consumed this reading pair. //id(solar_out_fails) = id(solar_in_fails) = 1; + // We believe the output sensor is reading slightly lower than the + // input sensor. We see a fair amount of hysteresis, and the bypass + // kicks in before the output reports lower than the input... but + // the roof temperature continues to rise. When it gets high enough, + // the bypass turns off again and the warm water is pumped out. But + // then the reported output temperature is lower than the input again + // and it switches off again. Repeatedly, each 5 minutes over the + // course of an hour or so. + // + // By adjusting the output sensor up by about 0.1°C we attempt to + // reduce this hysteresis. Overcorrection would mean that we keep + // pumping heat into the sky for longer than we should, which is + // much worse than a little bit of hysteresis when the heat *is* + // actually accumulating in the water on the roof even while we + // vacillate. + // + outtemp += 0.1; + if (outtemp == intemp) return; -- 2.49.0