[OpenTRV-interest] Adaptive comfort (and stuff)

Damon Hart-Davis dhd at exnet.com
Wed Jul 13 17:40:59 BST 2016


> On 13 Jul 2016, at 17:13, Chris Skerry <chris_skerry at icloud.com> wrote:
> Hi,
> My Evohome system takes account of outside temperature and requested time for requested temperature and starts heating early to achieve it.

Explicit temperature compensation is a fine thing, but probably most easily handled by the boiler than elsewhere IMHO, eg raising flow temperaure on cold days to be able to deliver heat faster and thus reach setpoints in a more consistent time.

1) "Optimum on" (and "optimum off") as some call it is something we do but in a rather simpler way by gradually ramping up towards the target temperature up to about 90 minutes before occupancy is expected for example.  Our system is not designed to control UFH or other very-slow-response systems.

> It also has a facility to set the number of boiler cycles per hour, if I remember correctly it goes from about 3 to 9.  This is to prevent excessive on/off cycles.  Under certain conditions when all TRVs have have closed the controller is still calling for heat.  So the boiler has to have a bypass.

2) One basic boiler controller setting gives the miniumum number of minutes on and off to reduce short cycling; a useful minimum value for our secure comms system is 4, thus ~7.5 cycles per hour maximum.

3) The system is set up to be kind to the boiler and try to avoid running it against closed valves.  But some sort of bypass is still advised.



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