Thermostat Idea

Mike T., Swampeast MO

Every year around this time and near the end of the heating season there seem to be LOTS of problems and questions regarding setback--both manual and automatic via "smart" stats.

Why not develop a TRULY "smart" thermostat to keep setback levels both sane and efficient? One of my older Honeywells says that it measures the temperature of the wall to which it is attached to learn how rapidly the structure responds to a call for heat and also how rapidly it looses heat.

Why not use this built-in logic to make automatic adjustments in the level of setback to ensure that the house is actually maintained for some period of time at the lower level? Remember that you only begin to save energy once the space is being MAINTAINED at the lower temperature! Should be a nice marketing tool to differentiate yourself as well...

I certainly imagine that this can be done without outside temperature input.

Uni R

Maybe even simpler...

The thermostat has a gain factor. We'll set that at 2x. It also has a timer that gets triggered whenever the thermostat sets itself back. The timer stops after the spaces reaches the setback temperatute (call that time T2). The next time (T1) is when the house needs to be back at temperature. At T1 - T2/2x the thermostat starts the boiler to get it back to full temp which should happen relatively close to T1. I realize different factors will effect how fast the space loses heat that may be different when it is gaining heat (solar gain, doors left open, etc.) but at least it could ballpark it for people. The key part is that it needs no extra sensors. Just pull a timer function off the clocking and allow the user to enter some factor to approximate the gain rate to the loss rate. Also, the timer logic needs to monitor if it doesn't reach the setback temp and the amount of time by the factor is the time to be back up at temperature then it comes back up to temperature at that point and leaves a message that it failed to reach the setback temperature.

hydronicsmike

Without Outdoor Temp?

What about areas like Calgary AB, where you go to bed at -40°F and wake up to 50's or 60's°F??

BillW@honeywell

Interesting ideas...

Right now, our VisonPro, PC8900 and Chronotherm 4 and certain Chronotherm 3 models feature "adaptive intelligent recovery". They remember what the temperature was over the past 3 days, and start the system so that the home will be at the setpoint when it comes out of sleep or leave periods, not just come on, like the old mechanical clock types did. It ramps the temp up in gradual steps, so on a very cold morning, the system may start recovery earlier than it would on a milder morning.

This feature usually is not found on the retail stats. The idea is to keep the stat easy for the homeowner to use, easy for the tech to install, and have the widest compatibility possible. I will send a copy of these emails to the R&D gang in "Thermostatworld", if I hear anything back from them, I'll post it here. Thanks for the feedback, and keep it coming!