Category Archives: HVAC Zoning

ubuntu’s librxtx with java-6-sun

If you want to use SUN’s java version with rxtx on any debian derivative system you’d be surprised to discover that jre can’t find rxtx libraries if you installed them using librxtx-java package. It’s because SUN does not adhere to debian naming and placing policies and looks for libraries in wrong place. Quick fix:

cd /usr/lib/jvm/java-6-sun/jre/lib/
cp /usr/share/java/RXTXcomm.jar ./
cd i386
cp /usr/lib/jni/lib* ./

That will make those libs available to SUN’s java and everything should work from now on.

Balanced zone controller

One of the nicest features of our new HVAC zone system is module called balanced controller. Basically it’s an algorithm calculating heat demand in every zone and opening and closing registers accordingly.

Here you can see that one of the zones (middle one) was fully open while remaining two were just barely moved, Then when this zone was satisfied in it’s heat demand it was closed and the first one was fully open to direct all hot heat into this zone to shorten furnace running time to the minimum.

I don’t have any statistic data to prove my theory yet but it seems to me that such behavior shortens greatly overall running time and simply saves us money.

HVAC zoning resurrected

A comment posted under one of my older posts reminded me that it can be a good idea to resurrect and finish my HVAC zoning project I shelved some time ago. Main cause I did so was that I couldn’t get dz compiled. I didn’t have time to mess with it any longer then, but I decided to give it a try this time. It turned out that over last two years Ubuntu project went forward so much that this time dz compiled successfully the very first time I tried. So right now I have a spider web construction on my desk consisting of two 1-wire temp sensors and two servos run by phidget boards. And they work. Servos are opening and closing according to changes in the temperature of my office. They have no influence as they aren’t running registers yet, but they proved to work. Now it’s time to run wires around the house and motorize registers.

Stay tuned.