Hi to you,

Recently I have come across this design and I have found it to have been very informative!

I have since recently implemented a much also similar design in my own applications such as in my house.

Thanks for your concurring information given to us.

Bill Shazzby

Please pardon my english, it is due to my not being originally an english person, thank you.

Posted at 5:03 pm on May 19th, 2009 by Bill Shazzby

Not a bad project. If you are seriously interested in micro-scada-like hvac monitoring/control you may want to check out this guys approach and combine the best of both worlds.
http://www.ourcoolhouse.com/scada.htm

I’ll bet neither can program a GE/Gentex ECM motor though, so good luck with that one.
Eh all pun aside. Good to see some tinkering with HVAC now someone needs to take it to the next level.

Posted at 5:44 pm on May 19th, 2009 by Steve

Steve, thanks for the reference article. Definitely a good read. The nice thing about both projects is that they are fully customizable to whatever hardware limitation there is, as the code is totally custom and can be written to do whatever.

Ourcoolhouse.com has definitely got the monitoring down. They should work on graphing all that data out and getting down to core savings both economically and energy-wise.

Marc Daigneault
HVACMonitor

Posted at 5:59 pm on May 19th, 2009 by Marc Daigneault

Mark,
No doubts at all. Things need to be taken to the next step here. The hvac/r industry is not going to bring about change. just consider ashre wiring schema. its not hing but an old-school head ache.it simply should not be used anymore. though few people will admit it. if you are interested i have quite a few hvac projects that are very advanced to say the least. (probably why i gripe and groan so much, comparing everything to what i know is possible)

Posted at 6:28 pm on May 19th, 2009 by Steve

Steve, email me with details about the HVAC stuff you speak off. You can find my details on my website.

Marc Daigneault
MGDengineering.com/hvac.htm

Posted at 6:39 pm on May 19th, 2009 by Marc Daigneault

I’ve been very interested in doing the same for my house. The one detail I didn’t see was the handling of the temperature regulation. What’s the best method/algorithm to prevent constant on/off switching of the ac/heat, while still maintaining a fairly constant temperature?

Posted at 10:49 pm on May 19th, 2009 by Tuckie

I just bought a thermostat that had rs232 out.

run it to a PC, (or in my case the Crestron processor) and you are all done.

Guys have been doing this stuff in home automation for decades now, how is this new?

Posted at 6:05 am on May 20th, 2009 by fartface

24 VAC is such a pain in the ass

Posted at 6:53 am on May 20th, 2009 by anon

I’ve been toying with the idea of doing something like this for a long time. Very nice implementation! However, my design approach as a landlord would be slightly different. I am more interested in monitoring and receiving alerts, than I am in actually controlling the temperature. This has real product potential if it can generate email or SMS alerts when something is wrong with the hvac: 1) Is it cooling properly, according to tenant thermostat settings? 2) is it heating properly? 3) is there any degraded performance accruing over time? In my approach (which I never actually implemented yet) all this information could be obtained by monitoring supply air temp vs return air temp. The Delta-T will tell you if the unit is heating or cooling as expected. It might also tell if there is a filter blockage, a freon leak, or even a severed outside compressor control line (lawn crew weed whippers do this ALL the time). Also would need to sense the setpoints of the thermostat, instead of control them. If an email alert can save me from replacing a burned out compressor, or when a filter needs replacing it would be awesome.

Posted at 10:52 am on May 20th, 2009 by pio

A+ write-up.

Posted at 11:50 am on May 20th, 2009 by andrew

The biggest problem in all systems is you can’t have a HVAC system that works well without proper flow control. I’m working on a project currently but it’s not ready for public yet but it contains multiple temperature sensors that can be installed around the house. Multiple points per room preferably. But in conjunction with some over the counter “vent” boosters. It allows for a much better control of ambient temperature of the entire house hold. I’m looking into adding some more intellegence into the system to account for past history and trends for current time of the year to be able to anticipate large temperature changes. As well as some angle sensors on the doors and windows that are actually used. Total dynamics of the house flow can then be monitored and controlled. The system is modular so it’s scalable to any size home. The use of standard vent “boosters” allows for retrofitting and upgrading instead of a complete HVAC system rebuild. The system also takes into consideration the total energy use and everything can be scripted to react to any any energy based constraint set. The control of the devices is done through what some may recognize if they use video editing software. A timeline based action script graphical interface allows you to set states of the device in a 24hour window based on whatever factor the user decides to use. Which can be: temperature, energy use, day of year/season, etc. More info coming soon.

Posted at 10:32 am on May 21st, 2009 by Roman D