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Redux 1984

Travis Johnson said:
This thread is kind of interesting...

With my new heating system it seems my thermostats are the dumbest part of the system. They just tell the control valves to come on, or go off. As a visionary, in the coming years I see that changing to intelligent thermostats.

The thing is, I have Radiant Floor heating, which is one of the best ways to go, but when the days go from say 40 degrees one day, down to zero degrees another day, and then right back up to 40 degrees again, I get this hot/cold effect. That is because my concrete slab takes about 8-10 hours to feel a change.

Now imagine if the National Weather Bureau or NAOA had weather forecasting data base. I could tie my heating system into that. My heating system would then have enough intelligence and data to almost predict what it would need to do 12-24 hours ahead of time. That could save me a lot of money in the long run. It would also even out the hot/cold spikes.

Really, I am being serious here. Right now the weather is predicted to get a lot colder next week. My intelligent boiler would already know this, and begin raising the temp of the slab up a degree or two in anticipation for the cold weather ahead.

Maybe we are not ready for this. Or maybe we already have it, I don't know. I know my place is not as bad as my dad's. He has oil fired heat (I have propane) so he cannot meter his hot water as well. When we get warm/cot spikes in temp, his house seems to be hot when its hot out, and cold when its cold out. A system that could use weather forecasting would really even out the heat.
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I haven't heard of thermostats being controlled that way, but there is a system for lawn irrigation that works that way. The system receives a signal which tells it if, and how much, it rained in the past few days, along with the cloud cover and temperature. The system then adjusts the irrigation to keep your plants alive without over watering. The disadvantage is that the system is expensive right now - about $500+ to buy if I recall correctly - and I think there's an annual fee for the weather information. So it's only worthwhile for people who use a lot of water, like a golf course. As water get more precious out here in Paradise and the electronics gets cheaper, I expect to see these systems become viable for home use.

Mike
 
Bart Leetch said:
"A system that could use weather forecasting would really even out the heat."

I don't think so only because of human fallibility.



Just an example of this is a 35% chance of rain predicted for Whidbey Island which for us comes out of Seattle where Seattle gets the rain & we don't.

When ever the prediction is 35% or less I just ignore it because it not happening.
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Something like a 35% chance of something is not enough to make a sound logic (as in computer logic) decision. 65% would be a different story. Also, local trends could be taken into account. Until our weather prediction abilities get better, the system would not be perfect, but it could indeed be an improvement in some cases.

Did you happen to notice Alfredo's post from earlier today? A big utility company in Mexico is researching using short-term wind forecasting data to predict the impact of wind-powered generation facilities on their power distribution system.
 
One thing to keep in mind is that I am only talking TEMPERATURE and not precipitation. Have you ever noticed that the weather forecasters almost always get the temp right, its the snowfall predictions and rainfall predictions that they are off on? I think we can predict the temperature enough in forecasts to adjust the boiler enough so that we won't be uncomfortable even if the temp is off by a few degrees.

Still think about it, if Albany, NY is 8 hours ahead of me, and is now in a cold front, and my current home is in Maine and in a warm front, my boiler can pick this information up. Right now its saying "its 45 degrees out, so I should run 76º water to keep the house warm." If this had forecasting ability, it would say "its 45º right now, but in 8 hours the temp is going to drop considerably, I'll start to compensate now." In this respect it would use more btus, but make me more comfortable. If the situation was reversed, it would use less btus and save me money.

We are only talking a few degrees here, but heat is all about BTU's and Degree days. The more we skimp on using btu's, and the more we can lower the degree days (a little bit over 9 months could add up), I think this system is viable.

Disclaimer: I am neither a weather forecaster, nor a heating tech!!
 
Robert Mickley said:
Ok your going to educate me here, Since the only experience I have with a boiler is my redneck home brew out door one. Why would the type of fuel make a difference? I would think it has more to do with boiler design than anything
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Robert, its not a foolish question. I have explained this before on here a month or two ago, but I completely understand if you missed that post so many days ago.

The difference is in the flame. With propane you can adjust the flame from 1% to 95%. The gas valve can lower or increase the flame as needed to increase or decrease the btus output. This is called modulation.

With oil, (#2 furnace oil) the flame can only be lowered to 65%. Interestingly enough it maxes out at 80%. That is because oil soots the injector and burner up if its not burning hot enough. It maxes out at 80% because it just plain does not burn as efficient as propane.

Okay...so now you know the difference, here is where it makes a big difference. With RADIANT FLOOR HEAT, my propane system senses the outside temp, and the temp of the concrete floor. As the temp outside goes down, it means my concrete slab is losing heat faster. It needs hotter water to maintain the same temp in my house. There is a specific chart called the "degree day chart" that shows this. If its say 32º outside, it states I need 76º water to heat my house at that temp. My propane boiler can hit 76º water because it can adjust its flame, and mix temp to achieve that definitive number.

My fathers oil based system cannot. His system is more on and off based. He can not get his water temp below 110º because his flame can just not go down any lower. So his oil system comes on, heats the slab up faster, but then shuts off for awhile and allows the slab to cool down. Its hot and cold, hot and cold, all the time...but that's how it works, and its fine to a point.

My propane system on the other hand, heats the water to only what is needed. There is no on and off, my circulating pumps run almost constantly, but this keeps my concrete slab from getting hot and cold, its just more even heat...again all because the different fuels allow the flame to be adjusted differently.

So which one is better? Well propane is now $2.30 per gallon and oil is $3.30 per gallon. Still btu wise they cost the same. That is because propane only has 91,000 btus per gallon and oil has 131,000 btus per gallon. If you do the math it comes out to .000025 cents per btu. By being able to modulate the flame,and not burn more btus then is what is needed to heat your home, propane is cheaper in the long run.
 
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