Results 1 to 4 of 4


  1. #1
    Join Date
    Feb 2008
    Post Likes


    In the building automation system, the HVAC system generally is the part of building management system (BMS), according to a survey earlier conducted in UAE and as per my experience, the BMS almost out of order, as well as the HVAC system such as the control of chilled water pump, FAHU operation….etc will be in out of use.
    I think the major drawback of the BMS is the required commitment at all levels throughout its operational life to maintain maximum effectiveness. Operation and maintenance cost might be higher compared to simpler management. Also there are lots of group of communication interface, there will have always some error in any electronic board. These jeopardize the smooth operation of the system. The Major energy consumer of the building, above 60%, is HVAC system. At present, I am taking some initiative for installing HVAC dedicated manager for our buildings by segregating from the BMS, and I think it will be a simpler and can be include more operational logic ….
    What you think..

  2. Dislikes oldhweller disliked this post.
  3. #2
    Join Date
    Aug 2003
    Fort Worth, TX
    Post Likes
    Most BMS/EMS systems are vastly underutilized pertaining to energy management. Mostly used for monitoring, on/off, and troubleshooting. That last item is part of many building managers/operators take advantage of the built-in trending tools of their EMS platform to diagnose equipment problems or locate energy waste?

    So I see no need to reinvent the wheel; just learn to better use what's already on your desktop.
    Psychrometrics: the very foundation of HVAC. A comfort troubleshooter's best friend.

  4. #3
    Join Date
    Mar 2009
    Several Miles from Sane
    Post Likes
    I can't speak for your part of the globe but in the USA the "BMS" (or BAS, EMS, EMCS, etc.) is quite often the foundation laid by the HVAC DDC control system itself. Energy monitoring, Lighting Control and other systems get added to or integrated into the initial BMS/HVAC system.

    I my neck of the woods the percentage of overall electrical cost, and in many cases overall energy cost, of the HVAC System is considerably less than the 60% you mentioned.

    As Shophound said, most of the time the BAS/BMS is greatly underutilized. Additional Training of Operating and Management personnel could result in greatly improved HVAC system operation as well as efficencies.
    If sense were so common everyone would have it !
    Never underestimate the power of human Stupidity !
    If folks took care of their cars like they do their HVAC Systems you'd see a lot more people walking !

  5. Likes oldhweller liked this post.
  6. #4
    Join Date
    Jul 2014
    Post Likes
    To get down to 'brass tacks', here's a simple but powerful example of how simple DDC controls can effect energy savings (not the front-end "BAS controls" - the working control algorithm is down in the 'lonely' DDC controller in the mech room).

    When a building is cooled down to setpoint there is a 'flywheel' effect - you've got a big 'cooling' train going on. Let's say the bldg. closes at 5pm. I've seen many time schedules set for that 5pm time to shut down the system: AHUs, chillers, boilers, etc. Keeping the 'flywheel' principle in mind, there's no reason why you can't shut off the chiller 1/2 hour, or depending the outside humidity, 1hr, before the building close time (eg, 4:30pm, 4pm). But you keep the chiller water pumps running to the 5pm shutdown time. No one's going to notice (unless you got a critical process facility).
    If you want to push the "DDC Smarts" to shut down the chiller even earlier, there's opportunity to set a schedule to close the AHU OADs before the 5pm shutdown to minimize the intake of humidity (I'd do a trend of CO2 levels before committing on that, but you'd be surprised how long it takes to effectively raise that). The power of the "DDC Clock". Energy = (Rate of Energy) x (Run Time). A chiller running 1/2 hr less every day over a year = nice $$$ savings & how much work was that? (in the energy trade that's called 'LoCo' - Low Cost ECM).

    Time schedules can be at the "BMS" level, but best to have the 'master' time schedule at the DDC controller in case the BMS/Network decides to 'take a nap'.

    See attached ECM PDF
    Attached Images Attached Images

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts