data logger

[twofer]

Just wanted to pop back in this thread and show you guys the logging I have setup for my Arduino system. Here you can see the past 24 hours of temp measurements from my thermal storage.

 

[DaveBP]

Dave, I am interested in the metal meters you speak of. I looked at them on e-bay. Do they make a gauge that you can attach to the surface? These look like the meat thermometers I currently use. If they all have those 5” probe ends, it prevents it from making direct contact to the surface an an in-accurate reading. Forgive my ignorance on this.

The bimetal thermometers I'm talking about are designed to go down into a thermowell. Kind of a pipe fitting that the probe end screws down into so it's surrounded by water but not in contact with it or under pressure.

I suppose you could get one to go on the outside of the pipe gooped up with silicone or something to make better contact and insulate it with the dial showing. I think it would give a delayed response to temperature change but much better than guessing. If you watch the auctions you can get them crazy cheap occasionally. My crappy eyes love the big dials. Read them half way across the room.

 

[deerhntr]

Just wanted to pop back in this thread and show you guys the logging I have setup for my Arduino system. Here you can see the past 24 hours of temp measurements from my thermal storage.

Nice Data. I really like me arduino too. I have a question on your plot. Why, when you charge your storage doesn't all of the temps(top,middle and bottom) converge to the same max value, then diverge once you begin to draw off BTUs, and the tank begins to stratify? Seems like at some point all the water in the storage tank should be a constant temp.

Just curious!

 

[twofer]

Just wanted to pop back in this thread and show you guys the logging I have setup for my Arduino system. Here you can see the past 24 hours of temp measurements from my thermal storage.

Nice Data. I really like me arduino too. I have a question on your plot. Why, when you charge your storage doesn't all of the temps(top,middle and bottom) converge to the same max value, then diverge once you begin to draw off BTUs, and the tank begins to stratify? Seems like at some point all the water in the storage tank should be a constant temp.

Just curious!

A couple reasons.

The first is that I haven't been charging my tank up to maximum capacity because I was seeing a good amount of idling (thanks to the graphing) due to the warmer weather and the low number of times the house calls for heat. It seems easier to hit maximum temps on the storage tank on colder days when the house is frequently pulling some the BTU's and keeping the delta higher. When the house isn't pulling heat very often the delta is lower and the pump isn't moving the BTU's fast enough. So to conserve wood I just load up enough wood to get most of the tank up to 170-175. I don't have any hard data but rather this is my best guess after watching the graphs.

Now the low temps from the bottom sensor are a whole different story. Since my propane tank didn't have a belly plug we had to fashion a dip tube for the return. In doing so I don't believe we made it long enough because the storage will get up maximum temperature and the boiler will idle for a long time with very little change in the bottom temp.

 

[jebatty]

Really great on the Arudino project. Neat chart. Congratulations!

I just rec'd in the mail yesterday 16 Dallas DS18B20 from one of the sites mentioned above. Today I attached 2' leads to 4 of them, soldered, heat shrink tubing, to use in another data application. At $1.60 each, can't be beat. I also ordered a stand alone K-type data logger so I can log the whole K-type temperature range. First use will be to log stack temp, which I can merge with my other logger data, and produce whatever charts I might want.

Mentioned in other posts my volunteer work with a 1m btuh Garn and 500K Wood Gun for a 501(c)(3) entity. Will start some data logging for them to get a visual on real world performance (might soften the hype rec'd from the dealers). This is a leaning institution, and data produced will serve impt educational and grant goal objectives. Also will address some operational issues and improve ability to maximize efficient operation of the systems, which are integrated with 11 LP staged boilers. I am suggesting to them to install a permanent, web-based monitoring system to provide educational info for their own use and the public. Will see what happens. Money is really tight.

BTW, a suggestion to all with enough experience to share, please volunteer and get involved with community organizations. The payback will be many times your own benefit.

 

[jebatty]

This is it on my chart posting, unless something really interesting comes up. My sensor locations now are accurate: top, down 12", down 24", bottom. Keep in mind this is as passive storage tank, except when loading. Draw down is by radiation/convection to heat my shop, no circs running. Time period was 46 hours. Below 0 temps at night, mid 20's daytime. Thanks for bearing with me.

EDIT: the title of chart is in error; Top, 1/3, 2/3, Bottom is correct, as stated.

 

[DaveBP]

This is it on my chart posting,

Interesting, Jim, how the bottom cools off more quickly from fully loaded and then after a couple hours cools off at about the same rate as the rest of the tank (parallel to the other higher traces).

I appreciate watching you guys develop these logging systems. I hope to do something like this, too. Someday. But I'll just plagiarize one of you. Good of you all to post this stuff so others that don't have the programming skills can be encouraged to put things like this together using your codes.

 

[jebatty]

Never say never. Added a sensor to measure stack temp. Chart shows stack temp / 2. Initial boiler load was about 2/3 full, let it burn unattended on start-up. When supply temp reached 165F, the circulator is "on." At that time I topped off the load of wood, that's the large spike in stack temp with boiler feed door open and firebox bypass damper open. I then again let it burn unattended, maximum on the draft fan, no fiddling with anything. The wood load was dry pine. It's starting to get too warm, day highs are now just above freezing, lows 0-10F. Boiler firing is every other day now.

 

[Hunderliggur]

twofer - What temperature is your controller set to turn on your circulator and what is the hysterisis value? Interestinghow it goes from 110 to 175. Do you have a protection valve (Danfoss or similar) on the boiler input?