Do We Need Ultra-Frequent Control?
The idea of sending a signal to a Keen Vent every few minutes troubles me, and I am not sure why.
When a thermostat gets information from a temperature sensor (Sensor 1), and either fires up the HVAC unit or shuts it down…well, that makes sense to me. Eventually the thermostat will reach its set point, and the HVAC system can go dormant for a while.
Now picture that same system with a secondary area equipped with Keen Vents and a separate temperature sensor (sensor 2) that is visible to a smart app. From what I have seen of the user- created smart apps, when the HVAC is running, the smart app will send signals to the Keen Vent every few minutes telling it to close down or open up a little more as it seeks the temperature set in the smart app for that secondary area. The problem is that the smart app can only control air flow at the Keen Vent, not the HVAC system. If the thermostat is set for cooling to 70 degrees (sensor 1), and the software for the Keen Vent is set for 60 degrees(sensor 2) , the smart app can open the Keen Vents all the way and never get there. It will futilely send signals to the Keen Vent until the cows come home, and it will not reach that secondary set point. It seems to me those smart apps make a promise they cannot keep.
I suspect that control system engineers have a name for this kind of problem, but I do not know what it is.
IMHO, in the same cooling scenario, usually you can easily determine which room gets cooler and which hotter, and that difference stays fairly constant, let’s say for the summertime during the day. With a little experimentation, you can open and close the Keen Vents through the SmartThings mobile app, until you find the sweet spot for your daytime living, and similarly for your nighttime living. Once this sweet spot is found, you can leave the Keen Vents there, at least during the daytime, without driving them crazy and wearing their mechanisms/batteries out, with a signal every few minutes.
I suspect you can set Keen Vents for one setting during the day, and one during the night, and your job is done. If the sun cooks one set of rooms in the morning and another set in the afternoon, you may have to refine that a bit. So maybe you need to change the vents settings four or five times in twenty four hours. You can automate this using the light dimming smart app, by the way (as stated above). For some reason, I like that better than forty or fifty settings a day, which likely do not improve anything.
Nope, I am not selling my latest whiz-bang app. I am just trying to understand why we need the super-complicated apps, when perhaps a very simple app would do. If I am all-wet (always a possibility), please educate me.