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    HVAC Automation Question

    This question may well be a little to broad to be answered as a single question, but I will lay it out here anyway, I can always post again with more detailed questions.

    So my question revolves around setting up zoned AC to keep different rooms at roughly the same temperature. I have a 2 story house and some rooms stay cooler than others, even though the HVAC guy has told me that the AC is balanced properly. What I am thinking of doing is putting in a 1-wire system to monitor the temp in the rooms upstairs (6 rooms) and setup dampers in my ducts for those rooms. This way I can have Homeseer watch the temp in the rooms and kick the A/C on/off and open/close ducts to keep the different rooms at roughly the same temp.

    I have never done anything with 1-wire, although the name makes me think it is not overly complicated, so I was wondering if the plan above is workable and if those systems work together well enough to achieve my goals as well as maintain a high WAF?

    Thanks in advance gang!

    #2
    Originally posted by chewie View Post
    and setup dampers in my ducts for those rooms. This way I can have Homeseer watch the temp in the rooms and kick the A/C on/off and open/close ducts to keep the different rooms at roughly the same temp.
    I'd also be interested in the reply to this, as I've been toying with the idea for several months. My upstairs office is always way too hot in the summer, and too cold in the winter. The bedroom next door however, is always too hot in summer and winter (my GF says that physics doesn't work in the bedroom for some reason).

    I've toyed with installing a fan in the stairwell to try and move air round the house and hopefully mix and even the temps.

    One of the issues I see with zoning my house, is that in general, the doors are never shut, so it would be hard to maintain a constant temperature in them.


    G

    Comment


      #3
      Originally posted by chewie View Post
      This question may well be a little to broad to be answered as a single question, but I will lay it out here anyway, I can always post again with more detailed questions.

      So my question revolves around setting up zoned AC to keep different rooms at roughly the same temperature. I have a 2 story house and some rooms stay cooler than others, even though the HVAC guy has told me that the AC is balanced properly. What I am thinking of doing is putting in a 1-wire system to monitor the temp in the rooms upstairs (6 rooms) and setup dampers in my ducts for those rooms. This way I can have Homeseer watch the temp in the rooms and kick the A/C on/off and open/close ducts to keep the different rooms at roughly the same temp.

      I have never done anything with 1-wire, although the name makes me think it is not overly complicated, so I was wondering if the plan above is workable and if those systems work together well enough to achieve my goals as well as maintain a high WAF?

      Thanks in advance gang!
      I did this. I also incorporated motion sensors so the dampers are only open when the rooms are occupied and the temperatures is outside of the defined range. bedrooms that are slept in are not dependent on motion between 9pm-7am.

      I also added 2 intake zones, one downstairs and one outside. Alfred (the HomeAutomation computer) determines which fresh air intake source is most efficient based on the mode (heat/cool) and comparing the average temperature of the open zones to the temperatures of the three different intake zones. if the difference between the intake zone and the average open zones is greater than a configurable #, alfred will run the system on "fan only" which is more efficient. this is great for when you want to just "move" air, rather than conditioning it. moving air is great for when doors are open, or when you want to bring in some cool evening air, or when you want to use the hotter/colder air from up/down stairs to make the other part of the house more comfortable.

      anyway, it't one of the largest, frequently used parts of my HA system, and it has gotten high waf. let me know if you have any questions.

      Ian
      Plugins:
      BLLogMonitor, BLGarbage, BLBackup, BLOutGoingCalls, BLUps, BLRfid, JvEss, DooMotion, Applied Digital Ocelot, AC RF Processor, UltraMon, PJC AVR 430, UPB, Rain8net, DSC Panel, JRiver Media center, Windows Media Player, SageMediaCenter, SnevlCID, MCSTemperature.

      Comment


        #4
        Thanks for the replies! This is definately in my plans, though probably a bit down the road as I am going to ease the wife into the whole HA thing and once she has a decent WAF then start adding some of the more complex items. I live is South Texas so I will probably wait until Winter to mess with my AC just in case...:-)

        Ian, when I get started down this path I may PM you with questions!

        Comment


          #5
          Originally posted by chewie View Post
          Thanks for the replies! This is definately in my plans, though probably a bit down the road as I am going to ease the wife into the whole HA thing and once she has a decent WAF then start adding some of the more complex items. I live is South Texas so I will probably wait until Winter to mess with my AC just in case...:-)

          Ian, when I get started down this path I may PM you with questions!
          bring it on!
          Plugins:
          BLLogMonitor, BLGarbage, BLBackup, BLOutGoingCalls, BLUps, BLRfid, JvEss, DooMotion, Applied Digital Ocelot, AC RF Processor, UltraMon, PJC AVR 430, UPB, Rain8net, DSC Panel, JRiver Media center, Windows Media Player, SageMediaCenter, SnevlCID, MCSTemperature.

          Comment


            #6
            Originally posted by completelyhis View Post

            I also added 2 intake zones, one downstairs and one outside. Alfred (the HomeAutomation computer) determines which fresh air intake source is most efficient based on the mode (heat/cool) and comparing the average temperature of the open zones to the temperatures of the three different intake zones.
            What are you using to physically select the different zones? What kind of dampers?

            Also, you should mention, if he's going to be working with damping zones, needs to have a dump zone, or a ... pressure relief valve (Ian, I think you were selling one a while ago??).

            --Dan
            Tasker, to a person who does Homeautomation...is like walking up to a Crack Treatment facility with a truck full of 3lb bags of crack. Then for each person that walks in and out smack them in the face with an open bag.

            Comment


              #7
              Dan,

              Believe it or not, I'm using a Rain8net relay. They operate on 24vac, same as the RCS motorized dampers I purchased from smarthome several years back.

              That's a good point regarding the "dump" zone. I got around that by utilizing a pretty complex system of keeping track of how many CFM were "open" at any given time and adjusting the blower motor speed accordingly. That is not easy, esp. on older units like mine. Newer 3 stage "smart" air handlers make this much easier. It just so happnes that I put the barometric bypass you speak of on Ebay right now.

              http://cgi.ebay.com/ws/eBayISAPI.dll...STRK:MESELX:IT


              Ian
              Plugins:
              BLLogMonitor, BLGarbage, BLBackup, BLOutGoingCalls, BLUps, BLRfid, JvEss, DooMotion, Applied Digital Ocelot, AC RF Processor, UltraMon, PJC AVR 430, UPB, Rain8net, DSC Panel, JRiver Media center, Windows Media Player, SageMediaCenter, SnevlCID, MCSTemperature.

              Comment


                #8
                Dang! Looks like I missed out!

                $25 for that ...might have been able to swing it in a few weeks!

                --Dan
                Tasker, to a person who does Homeautomation...is like walking up to a Crack Treatment facility with a truck full of 3lb bags of crack. Then for each person that walks in and out smack them in the face with an open bag.

                Comment


                  #9
                  Originally posted by drozwood90 View Post
                  Dang! Looks like I missed out!

                  $25 for that ...might have been able to swing it in a few weeks!

                  --Dan
                  Well, it's just sitting here, so let me know!
                  Plugins:
                  BLLogMonitor, BLGarbage, BLBackup, BLOutGoingCalls, BLUps, BLRfid, JvEss, DooMotion, Applied Digital Ocelot, AC RF Processor, UltraMon, PJC AVR 430, UPB, Rain8net, DSC Panel, JRiver Media center, Windows Media Player, SageMediaCenter, SnevlCID, MCSTemperature.

                  Comment


                    #10
                    I also do something similar to completelyhis.. i adjust my blower speed based on MANY factors, not just how many CFM of zones I have open but also on how much service i really need.....

                    the compressors in my zones(1 for each) automatically adjust to provide a constant 45 degree coil temp at center.. (usually nets me 47-50 degree air in cooling)...

                    I use a module in my furnace from aircare automation that will connect to any standard PSC furnace motor and make it variable speed... it takes an RS485 MODBUS connection so that i can control it and read the fan speed RPM...

                    I also use a static duct pressure monitor from building automation products. connected to my ocelot as a 0-5 volt signal... the static pressure varies based on filter status, how much water is on the evap coils etc.. so i can make blower speed corrections as needed to maintain the correct air flow...

                    I too also will sometimes move air from one room to another without conditioning... if you open the return in a room but close its supply.. open a supply in a nearby room and close its return, you will effectively move air from one room to another... works great!...

                    without some form of static pressure control, either a baro bypass or dump zone or variable speed.. you will shorten the life of your blower motor.. and also have a lot of wind noise / over conditioning of the space...

                    I actually prefer using the older air handlers and retrofitting as opposed to the new variable speed systems.. the new systems unless they are specifically set up for zoning, or use their zone panels just get 'lost' and dont know how to handle the quickly varying capacity requirements of a zone kicking in or out....

                    if you are going to zone with air -conditioning its also a good idea to make sure you are using a Txv and not a piston.. (thermostatic expansion valves are much better refrigerant metering device than a piston) this will prevent most coil freezing on low capacity system calls....

                    using outside air can be a double edged sword in the summer... remember humidity can eat up as much as 30-40% of the energy usage your A/C consumes if you are dealing with dewpoints in the high 60s into the 70s...

                    so make sure to program your outside air intake not to open just on temperature alone.. if that 70 degree air you pull into your 76 degree house at night is moisture laden your energy savings are gone gone gone the next day when the A/C has to pull that humidity back out...
                    -Christopher
                    PerfecTemp - the Most advanced HVAC system I've ever Built - and its in my House

                    Comment


                      #11
                      Christopher,

                      Good to see you're still around! Can you say if you're using the V, B, or N series controller from AirCare? Also, where did you get your RS485 MODBUS controller, and did you write your own control for it?

                      reutside temp/humidity, that's a good reminder, thanks for catching that! I do have temp/humidity sensor for outside and it is based on both. I've kind of been feeling that out, though, as I don't know specific numbers to compare to. Do you know of any charts or any such thing that show XX humidity = XX "feels like" temp. I've compared humidity inside to humidity outside, but again, I don't know any specific data that says, "difference of more than XX is bad."

                      Sorry to hijack the thread.....

                      Ian
                      Plugins:
                      BLLogMonitor, BLGarbage, BLBackup, BLOutGoingCalls, BLUps, BLRfid, JvEss, DooMotion, Applied Digital Ocelot, AC RF Processor, UltraMon, PJC AVR 430, UPB, Rain8net, DSC Panel, JRiver Media center, Windows Media Player, SageMediaCenter, SnevlCID, MCSTemperature.

                      Comment


                        #12
                        there are heat index charts... however I find in summer that for me here in ohio i like to keep the indoor dewpoint in the low to mid 40s tops... that seems to make things seem the most comfortable if im running at low-mid 70s for target indoor temperatures....

                        id have to check.. but im thinking i run the ACV-1081 controller by airecare... I have been running it for over 4 years now... so to the nay sayers that say you cant run a PSC motor on a TRIAC drive... it works well... heck when i was in the HVAC biz.. I replaced many a blower motor on a normal furnace that were less than 4 years old.... that ACV controller has a MODBUS port on it... and then I wrote a program in VB using a control I downloaded for free.. called "mod102"..I can send it to your email if you want it.. however it is not dot-net compatible.. there are several other freeware modbus controlsd that are out there now for use with dot-net.. which i need to completely re-do my HVAC program... you are welcome to my source code but i fear you will be confused as it does more than just fan speed control...it also talks to my custom boards and to my modified mini-split units.... basically my A/C is ductless mini split inverters turned into ducted mini split inverters wit ha custom interface.. and still maintaining the central blower...

                        however complicated the code may look the principles I go on are fairly simple...

                        1] I manually through trial and error set a default blower speed for each zone scenerio... zone 1 only calling, zone 1 and 2 calling, zone 1 and 3 calling, zone 2 only, etc etc.. those became my defaults...

                        2] I then set a minimum speed 'factor' / multiplier.. for instance if the default for zone 1 is 50% fan speed.. the minimum in cooling with high dewpoints might be 50% X .75 .. that gives me a minimum fan speed..

                        3] I then set a maximum... which typically was when i reached just shy of .5 inches of water.. (manually measured before the BAPI unit).. so I might say .50 * 1.30 is the max speed for zone 1 only.....

                        now my limits are set...

                        4] so next i look at the setpoint to room temp differential... if the differential is 5 degrees or more im running max fan.. (which will cause the compressor to ramp up).. now once I begin to come into reach of my setpoint i start ramping down.. my target is to be at minimum speed when I reach the setpoint.. the compressors will run when at setpoint for a little while... if i come off setpoint its going to ramp back up a but.....

                        5] next I put some other factors to use... if the humidity isnt real high my minimum fan speed wont be quite as low... colder air removes more humidity.. more air cools quicker.. if I dont need to humidify then lets get this placed cooled off and shut down the system.... if i have high humidity.. slow the fan down so the system will run longer and yank more moisture....

                        6] stale-mate protection... ok its hot out and I seem to just hover at that 2-3 degrees above setpoint but never get closer to my target.. so thats where a time factor kicks in... i start incrementing a counter that the longer I sit at one temperature i will slowly begin to ramp back up... each timer i gain a degree the target is set 1 degree lower.. I must reach my new target to clear out the extra fan speed added in... once i get to within 1 degree reach I utilize half of that factor... if i fall back to 2 degrees off then the full value is brought back in... if I reach setpoint.. the factor is cut in half permanently.. at setpoint and at 1 off no more adding is done to the factor.. prevents overshoots...

                        each zone has its own factor being added in... and it works real well...

                        the way i am doing this control is very similar to the way I did a couple of commercial buildings back in the 90s utilizing honeywell compressor unloader controllers, Mammoth VARI-CONE and a barber coleman network-8000 controller... wow how things have come along!!

                        in the works being tested for me is utilizing static pressure for everything and doing away with the manual factors.... I'll still have factors but the base will be static pressure based... and also vent-closed or true bloicked filter, frozen coil indication ,etc... although i let the inverter A/C units handle their own control... those units follow my lead.. if I move more air they ramp up.. if i move less air they ramp down... plus im feeding them temperature info so they eventually will shut down.. and then I follow them... when i get a shut-off signal from the unit i cancel the zone call on my end...

                        -Christopher
                        PerfecTemp - the Most advanced HVAC system I've ever Built - and its in my House

                        Comment


                          #13
                          Originally posted by cadillackid View Post
                          however complicated the code may look the principles I go on are fairly simple...
                          How do you handle a situation say where one zone is calling for cooling, and another is calling for heat? Trying to run both at the same time would probably be a 'bad thing' (tm). Would you cool down the zone that needs the cooling, then shut it off, and heat the other one? Or vice versa? Or something else?


                          G

                          Comment


                            #14
                            I don't know about Christopher, but with my setup if that were to happen an event would trigger that would equalize the temps in those areas by running the air handler in fan only mode with both of those zones open.
                            Plugins:
                            BLLogMonitor, BLGarbage, BLBackup, BLOutGoingCalls, BLUps, BLRfid, JvEss, DooMotion, Applied Digital Ocelot, AC RF Processor, UltraMon, PJC AVR 430, UPB, Rain8net, DSC Panel, JRiver Media center, Windows Media Player, SageMediaCenter, SnevlCID, MCSTemperature.

                            Comment


                              #15
                              actually it will work with my setup... for one.. when its warm enough that the situation might occur I am in heat pump mode... with there being a coil in each zone i can run the units in different modes.. however my house is only 1450 sq ft ranch so i dont have that situation occur.. and when I have one zone over shot and one undershot i do as completelyhis states and shuffle air... HOWEVER air shuffling really only works when the zones are adjacent... in my case the zones 1,2,3.. 2 is in the middle so if i need to shuggle air from 1 to 3.. not easy to do... sure i can open returns and supplies in Both zones and hope to get some movement.. and it will equalize to some point...

                              most often when the scenerio occurs is in winter when there is a fire in the fireplace in zone 2 and my roomie in zone 3 is trying to stay warm... so I will open the return in zone 2 and the supply in zone 3 and shuffle the air... if I drop 2 degrees below setpoint then it will open the return in zone 3 and go for 1 stage of heat..... but that only happens if it is super cold and windy..... even with Andersen windows.. those ice cold windy days will require some zone in some mode of heat at some point...

                              the design is for a small amount of heat to be running most all the time.. thus emulating the even-temp of hot water heat... which for those that have it.. they know it is very warm very even / comfortable heat....

                              now if i super-heat(overshoot) a zone.. say zone 2 and im cooking like crazy and its cool outside.. I will activate the ECON mode.. (a 6 inch duct with a 2 speed 500 CFM blower) that will suck in outside air and toss it into the HVAC return....)....

                              generally speaking in ohio.. Heat always takes priority.. and all HVAC systems are designed to Fail-to-Heat.. for instance if zone 2's heat pump becaomes non-responsive or errors out... all heatpumps are shut down and the system goes to fail-in gas heat mode... if the Homeseer control goes down the micro controllers switch to fail-safe gas heat mode.. if the micro controllers go down.. the blower fails to 50% and a mechanical thermostat keeps the house at 50 degrees.... enough to keep the pipes from freezing....

                              if the power in the house completely fails, a mechanical thermostat and a "warm morning" gas heater on millivolt T-stat will keep the house from freezing.....

                              I also have the micro controllers, and homeseer server connected to a "cyber power" that is accessible remotely.. so If the server dumps completely i can power cycle it remotely....
                              -Christopher
                              PerfecTemp - the Most advanced HVAC system I've ever Built - and its in my House

                              Comment

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