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Thread: HVAC Cooling, connecting to something not a Zone valve?

  1. #1
    Automated Home Ninja marcuslee's Avatar
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    Default HVAC Cooling, connecting to something not a Zone valve?

    Hi All,

    I'd like to provide cooling, but not a zone valve object.

    To be precise, it's to a Relay object, configured as a simple Pulsed, On/Off load. This On/Off controls a simple push button on either Open/Close of some velux blinds.

    Ideally I'd like to be able to connect it this relay object (which is itself connected to a bunch of other things like macros, and DFP menus etc).

    Would anyone have any ideas?

    Thanks in advance,

    Marcus

  2. #2
    Automated Home Ninja marcuslee's Avatar
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    Thanks for taking the time to read the post Chris.

    To reword: I've got some Velux blinds which operate by Idratek relaies, to either close or open.

    I wanted to configure Cortex to close the blinds when the room temp gets above a set point (and open again when it goes below a set point).

    I can't seem to figure out how to do this as the HVAC connections only allow connections to zone valves - any insight/advice?

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    Automated Home Legend chris_j_hunter's Avatar
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    how about using a virtual boiler, with the blinds inverted, as it were ?

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    Automated Home Ninja marcuslee's Avatar
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    Quote Originally Posted by chris_j_hunter View Post
    how about using a virtual boiler, with the blinds inverted, as it were ?
    Thanks Chris. I don't have this bit automated, so haven't been familiar (up until now!) with this object.

    Just going to see if this will do the job, the only thing in my mind is how I can stop it bouncing the blinds ie if it goes over the cooling threshold, it closes the blind, then temperature drops, and it opens the blinds, but then it goes over again.

    (Originally I had it in mind it would be one way thing / hadn't really thought it through, ie it just triggers it to close, then someone manually opens it later with the non automated velux remotes, in the afternoon).

  5. #5
    Automated Home Legend Karam's Avatar
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    Marcus,

    Ah, I see. When you say 'set point' do you mean the set point that your cooling/heating is going to be working to or do you mean some fixed value which you have in mind, or some profiled value which is not the same as the one used by your heating/cooling controller? Remember that the set point from an HVAC object (which would normally be used to control the heating/cooling) is a complex signal which can vary due to profile, occupancy, outside conditions and user interactions. Nothing to stop you using such an object as a 'virtual' object just to give you some of its benefits such as set point profiling and occupancy sensitivity without allowing other interactions, but don't know if this is what you had in mind.

    Another option is to use direct temperature threshold directives perhaps coupled with macros and/or logic to give extra intelligence. For example in one installation I had blinds controlled based on room internal temperature as well as light levels. So a temperature threshold in the room was set to trigger a macro. A filtered version of the light level signal for that room (see logic gates) was also checked to get a measure of if it was 'sunny'. Either of these thresholds would then trigger the same macro which itself would check if BOTH thresholds had been exceeded and only if so then the blinds were closed and then the macro disabled itself. The scheduler was used to re-enable the macro every morning. The latter to create the one shot effect. Of course which signals you might use to make decisions is an interesting question in itself and I'm sure might vary with different setups, but maybe this gives some food for thought.

    BTW these same blinds were also being automated for other purposes. The property had only east and west facing glazing. So when the property was detected as unoccupied a regime of operating the blinds in turn in order to gain/retain some heating from the sunshine was activated. If the house was occupied a different set of actions was in place. Also unoccupancy dependent - a directive to automatically close the west side blinds later in the afternoon if sunny in any case to mitigate sun bleach. I don't know how well this all works in practice as I can only go by the clients requests/reports but amazing how much fun you can have with just a set of blinds...

  6. #6
    Automated Home Ninja marcuslee's Avatar
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    Quote Originally Posted by Karam View Post
    Another option is to use direct temperature threshold directives perhaps coupled with macros and/or logic to give extra intelligence. For example in one installation I had blinds controlled based on room internal temperature as well as light levels. So a temperature threshold in the room was set to trigger a macro. A filtered version of the light level signal for that room (see logic gates) was also checked to get a measure of if it was 'sunny'. Either of these thresholds would then trigger the same macro which itself would check if BOTH thresholds had been exceeded and only if so then the blinds were closed and then the macro disabled itself. The scheduler was used to re-enable the macro every morning. The latter to create the one shot effect. Of course which signals you might use to make decisions is an interesting question in itself and I'm sure might vary with different setups, but maybe this gives some food for thought.

    BTW these same blinds were also being automated for other purposes. The property had only east and west facing glazing. So when the property was detected as unoccupied a regime of operating the blinds in turn in order to gain/retain some heating from the sunshine was activated. If the house was occupied a different set of actions was in place. Also unoccupancy dependent - a directive to automatically close the west side blinds later in the afternoon if sunny in any case to mitigate sun bleach. I don't know how well this all works in practice as I can only go by the clients requests/reports but amazing how much fun you can have with just a set of blinds...
    Hi Karam,

    Thanks for reply - that's exactly what I'm aiming towards actually, but indeed your reply really gives me something to aim for, for sophistication.

    And indeed I'd completely forgotten about direct temp threshold capability - I'm so used to just [trying to] using HVAC object to do anything to do with heating/cooling!

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