It feels like there is some similarities with the conversations going on over on Something has gone quite wrong with my 8kW Daikin today! - #86 by johncantor
I’ve created a simple system volume simulator tool here, I was trying to get my head around starts per hour, minimum system run time etc, Il try and do a longer post about it soon: https://openenergymonitor.org/tools/volume_sim.html.
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That tool is great.
However would it be possible instead of setting a number of cycles an hour to be able to set a min temperature where the heat pump starts a new cycle and a max temperature where it exceeds the setpoint hysteresis so ends the cycle. That’s how my Ecodan appears to operate.
That would then help to show the effect of changes to volume on the length of time between cycles and cycles would always be starting from the same temperature.
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Great tool, matches the behaviour I see quite well.
How about changing “Cycles to simulate” to “Period to simulate”, defaulted to 6 hours? I feel this makes it easier to compare when switching between different scenarios. Then the title above the chart would say how many cycles it’s showing.
Some heatpumps will often boost at the start of the cycle to get up to flow temperature, meaning a shorter cycle or ending at a higher flow temperature. Not sure if that’s something you want to model though.
Is this assuming some fixed indoor temperature? Could that be an input?
Here’s model of my system, compared to actual running:
https://emon.cryosphere.co.uk/ashp?mode=power&cop=1&start=1731369480&end=1731391470
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