Tracking the effect of changes

Brian_74

Thanks to Rod, Steamhead, and Jamie I have a new hobby--learning about my vapor heating system, and coming up with future plans. My goals are to improve the safety, and then the efficiency of the system. I had a professional check out the system earlier this month and he gave it a clean bill of health, so I thought I could work on the efficiency.



Since I have the luxury of time, I wanted to get some idea how different changes (e.g., lowering the pressure, keeping the water level at the marked level instead of above it) effected the overall efficiency of the system. I thought that I'd take weekly gas meter readings and then divide the weekly usage by the weekly number of degree days (from <a href="http://www.degreedays.net/">http://www.degreedays.net/</a>). I'm not sure what that result would be called, but if I kept doing that and never made more than one change per week, I figure I'd have <em>some</em> idea whether I was going in the wrong direction. If that ratio got bigger, then the system would be running less efficiently.



What do you think? Is there a better way?

Unknown

Hour Meter?

Hi Brian-  .Finding a measuring method that correlates to anything worthwhile isn't easy to do as there are so many variables you'd have to measure.  Since the economic efficiency is based on the fuel burned I've often thought of hooking up a hour meter to the burner circuit to time how often the burner is on (burning fuel)  I think you might be able to see trends over perhaps a few months  though I doubt if you can monitor things close enough to detect a slight change in operation relatively immediately and without a quicker feed back I think it would lose any benefit. Maybe monitor burner hours vs fuel used and degree days might be worth while.  With the boilers, things like pipe insulation, venting  etc. are all to cut down burner time.  One of the things that makes a big difference to burner time /fuel savings is if you can live in a temperature a few degrees cooler. This is quite viable though there is a period of uncomfortable acclimatization. There was a good discussion on here last winter about the benefits of setback with a steam system and the general conclusion was that a setback of more than 5 degrees isn't beneficial as you use more run time making up the temperature differential and less run time just maintaining the temperature. I've often wondered if increasing the insulation on the boiler and the returns would be a benefit as it would theoretically shorten the time to bring the water to a boil between cycles.

- Rod

Jamie Hall

Welcome

to the slightly wacky world of optimizing steam systems!  It's fun, and I'm glad to know I'm not the only one out there...



I run oil, so it's not quite the same, but I do exactly the same kind of thing: record oil usage relative to degree days.  Rod, by the way, has an excellent idea in hooking up an hour meter (run time meter) to the burner, but you'll want someone really familiar with the electrics in you burner to do that.



You will find that there is a lot of variation left in your data after you allow for the degree days, and part of the fun is figuring out where that variation is coming from.  In my case, much of it is wind speed and wind direction -- so you might want to keep a record of that, too.



Unfortunately, the signal you are looking for -- the variation in efficiency with changes in the system -- is rather small relative to other sources, and you may have trouble picking it out of the noise in the data.  I certainly have!  It's there, but...



I use Excel to store all the data, by the way, and also to do the calculations and a bunch of slightly funky graphs...



Have fun!

Brian_74

Wind. There's another thing I hadn't thought of.

Thanks Rod and Jamie. I see that this is more complex that I had thought--and I already thought that it was going to be complicated. I've set the thermostat about as low as I think I want to. Last winter I had it at 58° (24x7). I got used to it, sort of. I was hoping that I could improve the efficiency a bit and raise the temp with the savings. Gas is supposed to be cheaper this winter, and I don't think I can take 58° again. I'm trying 63° now.