Where I’m at, the temps flip-flop day to day, even hour to hour. In the morning it’s 35° outside, and by evening it’s 79°. I gave up keeping up with the temps and shut my unit off for the time being.
My question is why can’t HVAC units be programmed to say that if the outside temp reaches n° and the inside temp reaches m° cold, turn on the heat; conversely, if the outside temp rises to n° and the inside temp reaches m°, then turn on the AC?
My thermostat already knows the outside and inside temp, but I still have to manually switch it back and forth. I want a system that I can just set it and forget it all year round.
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Most thermostats do not have an external thermometer or internet connection.
They achieve comfort by setting a desired min/max temperature that ignores outside temp because that has nothing to do with indoor comfort.
I have an Ecobee that is set to heat to 68°F and cool to 78°F in the daytime. The only time I care about the outside temperature is when I could open a window to save money.
My thermostat has a hot and cold setting that will heat when cold and cool when hot- I can also set it to a mode based on outside temp or time of day. You might just need a smarter thermostat.
If you want your climate control to be automated, you need to automate it.
I used to be a building automation technician for commercial buildings. Simple temperature control is standard for them and easily achievable on your own with consumer hardware, but you need to know what you want your system to do and then do your research on the hardware and software necessary to achieve it.
You may be interested in something like HomeAssistant, where you set it up on your own, or you might want an installation company to come in and set up something like Control4 for you.
You could also go super simple and run a wire from the unit to a thermostat or temperature relay. Then you just set up the temperatures you want it to turn on and off at.
My Nest thermostat does this. And I use Nest Sensors to adjust to temps according to time and location in the house.
There are a lot of smart engineers that design those.
If you have an external temperature measurement it helps. But it can’t see the difference between a cloudy day and a sunny day.
If you connect it to an online weather service that helps, but it’s still hard for it to know how much the sun heats your home due to big south facing windows for example.
This is something AI could be useful for. Feed it forecast, inside, outside temp and let it figure out how to balance those against each other for your home. I’m not sure there are many systems like this on the market yet.
You don’t need to go to that level of complication.
Two sensors in combination, one that detects current heat input one that detects absorbed heat. These modules would be placed about the outer walls.
Then calculate how much heat is going to radiate into the building the rest of the day.
And it can compensate.
We don’t need to be more than a fraction of a degree off and a system like that would be amply accurate.
What kind of sensor do you suggest for measuring that? I’m genuinely curious why they are not industry standard.
My guess is price and/or robustness. The RTCs we use are cheap and durable.
Truly It’s not my line of work so I’m not going to start randomly recommending products, I don’t think it’s fair to talk out my ass hahaha
What I can say however, is the reason I was so bold in my assertion previously, was that I personally do a lot of hobbyist electronics, and wiring up temperature sensors is very simple. It’s very much a trivial aspect to basic circuitry, because heat is such an aspect. It’s in your most basic things from coffee pots to hair dryers but even down to smaller electronics, bulbs and projectors, everything really in its own way.
And then my father was a highly trained meteorologist with the government of Canada for 43 years and then another 10 of consultancy, they scouted him because he was the 100% in all courses math superstar at his university for his year.
My father taught me a lot about how heat is measured and it’s a huge concern in a way that the average weather watcher doesn’t understand. It’s talked about in Watts per Square Meter. So that could be how much heat a structure may absorb per square meter, or perhaps how much heat is dissipated per second in a certain wind.
That’s a major and primary concern of anyone in the agriculture industry, think for example a farmer that holds a barn full of cattle, he absolutely needs to know how much heat that building’s going to dissipate so he can plan for heating.
But it doesn’t end there, it goes into so many different areas where heat is an issue, and weather is the primary driver of heat transfer.
So I guess in summary, a solution is trivial, I’m not sure if there’s an official product, but we’re not talking rocket science! Edit: I guess in a way it’s pretty cool and it’s pretty complicated, but the thinkings has all been done by people smarter than me I’m just saying it can be put together and lots of people probably do this every day.
Edit2: I guess also my brother-in-law was a graduate of 4-year electronics program and he ended up working at our local eh price where he designed some forms of heating control systems but to what degree I know not. We talked a bit about some of the egghead stuff so I think in summary it’s doable.
Control theory is a bitch
You don’t really need complicated control theory for HVAC (at least, on a per-room or house basis) , since the system has such a huge heat capacity and takes a long time to change. Simple set point control with 100% on/off operation and a 2 degree dead zone gets the job done
That’s generally true for most HVAC applications. Bang-bang control creates limit cycle behaviour and as long as a small oscillation in temperature is acceptable, it’s a nice simple solution.
OPs problem seems to be a discontinuity between the two limit cycles, heating and cooling. The way to tackle this is to make time series vectors of all measurements and compare them with the subjective sensation of the room temperature. That should inform the relevant set points for the control actions.
I do exactly what you’re wanting with a smart thermostat integrated with Home Assistant. Because my old, horrible apartment is poorly insulated I have everything automated based on indoor/outdoor temps.
Why do you care about outdoor temps for your indoor setting?
If the outside temp is hotter there is no need to heat and if it is cooler there is no need to cool, because the house will even out with the temp.
It is slightly more complicated because of sunlight heating the building, but there is no need to spend energy changing the temp a few degrees when it will happen due to changes in temps outside. Like there isn’t a need to run the AC in the evening shortly before dark if it is only a couple degrees too warm inside because it will cool off on uts own pretty quickly.
But that’s why thermostats have a range and turn on/off cool/heat as needed?
If you were gone for a day with everything off then it would make sense to not overshoot. But when you are home it’s not like it goes from 30-60F instantly outside. As the outside gradually changes, so does the amount of heat or cooling on the inside.
Yes, this entire post is in search of a thermostat and it’s hilarious. Bizzaro.
There are experiencing hysteresis!
Mine is amazing, I set it and no matter what the temperature is outside it stays the same inside!
When you have poor insulation then the colder it gets the higher you want to set your thermostat because the indoor temperature reading won’t be as accurate since your exterior walls are leaking.
Additionally, we like to open our doors when it’s warm enough outside but also sometimes when it’s freezing cold. Using inputs from the door sensors, outdoor temperature and indoor temperature I can automate fans and switching off heaters.
Love that all you random fucks assume I’m a moron, thanks for that. Can’t get enough of the dumbass hivemind logic on Lemmy.
