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Design a 3 story apt building

Tom_133
Tom_133 Member Posts: 883
Hey all,

So I am involved in designing the heating system for a 3 story, 31 apts, a couple other random heating spots in the building, so maybe 40 zones or so. Not a big dealt but was curious what some of you do? They want zone valves for each apt, each apt will have about 16' of baseboard, and I imagine a 3/4" balance setter. The building is roughly 68 x 32, and my plan was to break my header up so each floor would have its own pump, so 4 zones total (basement, first, second, third, hot water) on the header. This would mean smaller pumps and a little simpler to control and troubleshoot. Thoughts?

Also, I finally broke down and bought Siegenthalers design program, I am just waiting for it to get emailed to me, so I can figure up a bit more precisely what the sizing demands will be.

Thanks tom
Tom
Montpelier Vt

Comments

  • Intplm.
    Intplm. Member Posts: 1,882
    Have you considered having point of use zone valves at each radiator?
    Or is there a set of specifications that you are required to follow that would not allow for that?
  • mikeg2015
    mikeg2015 Member Posts: 1,194
    Pipe it reverse return with variable flow primary and you can eliminate the expensive balancing valves and maintain a lower return water temp. You will probably have $4k into all those valves and another $4k to pay a T&B contractor. Put it into the better piping arrangement. Run 2 mod-cons in parallel to get the flow rate needed and a wider turndown ratio.

    Remember that due to stack effect, lower floors need just a little more radiation than upper floors.
  • Zman
    Zman Member Posts: 7,561
    Remote zone valves are a pretty common and easy setup.

    Reverse return is great for balancing , sometimes the layout can be a challenge.
    If you use balancing valves, the Calleffi circuit setters are easy to set with no outside contractors needed.

    It would be simpler to use one Delta P circulator. You should be able to find a Taco Veridian or Grundfos Magnum that would match up well.

    The stack effect should be minimal if the building is constructed reasonably tight. I have found that the upper floor corner units underperform if the radiators are not upsized. A room by room heat loss will make this apparent.

    I like Siggys software. You won't be able to model flow on 40 zones and it won't have curves for many of the new ECM circs.
    You can use the flow and headloss numbers of the circs in the program to build a system curve and select circs that way.


    "If you can't explain it simply, you don't understand it well enough"
    Albert Einstein
  • SeanBeans
    SeanBeans Member Posts: 520
    As a multifamily service guy recently, I despise zone valves mounted inside the baseboard!! FWIW
    delta TAlan (California Radiant) Forbes
  • EBEBRATT-Ed
    EBEBRATT-Ed Member Posts: 15,453
    I would not skip the balancing valves. I would also put the zone valves in the basement if possible. Too much greif getting into apartments on no heat calls
  • Tom_133
    Tom_133 Member Posts: 883
    I appreciate the input guys.

    The design is up to me. The last one they did was zone valves on each zone, the zone valves will be in the common hallway above the drop ceiling. I liked the idea of smaller individual pumps per floor so its easier to troubleshoot and control and when its broken much simpler to get parts when its smaller pumps like a taco 3452, they stock them now. Im not saying its the best way, thats why im asking a multitude of counselors.

    I will probably do Caleffi balance setters for the ease of piping and knowing I have it right.
    Tom
    Montpelier Vt
  • hot_rod
    hot_rod Member Posts: 22,022
    This is the perfect place to use balance valves, properly set they will pay for themself in comfort and fuel savings. There are some modulating zone valves that can be used as on/ off and flow adjusters.

    If you know exact flow rates you can buy automatic flow setters, PIBV type.

    I agree with a delta P circ, or two if you need to split the job.
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • Steamhead
    Steamhead Member Posts: 16,796
    I'd do 2-pipe steam, using something like Slant/Fin Multi-Pak 80 baseboard with the 1-1/4" steel element. TRV and trap in each apartment, Tekmar 279 to cycle the boiler, vent the heck out of the steam mains and dry returns, and you're done- don't ever have to drain the system to do repairs. If you want to get fancier, do a separate zone for the southern exposure with its own 279.
    All Steamed Up, Inc.
    Towson, MD, USA
    Steam, Vapor & Hot-Water Heating Specialists
    Oil & Gas Burner Service
    Consulting
    ZmanAMservices
  • Henry
    Henry Member Posts: 998
    I did a school with 80 classrooms. Each classroom had a vandal proof Danfoss thermostatic valves. It is piped reverse return with constant circulation. The modcon is piped primary secondary. It is the second year, and everyone is happy. Most apartment blocks here are reverse return with constant system pump or pumps. Here is a 100 unit apartment block 1.5 million in heat and a 500 feeding 3 119 gallon storage tanks. This one has no control in each apartment as most of our apartment blocks except the high en units. No complaints from anyone over this colder winter. The VWH just developed a leak between the heat exchanger and pan due to the gasket. It will be fixed this week.
  • Henry
    Henry Member Posts: 998
    BTW, we vent through the roof and get combustion air sidewall when the chimney is too high.
    Intplm.
  • GroundUp
    GroundUp Member Posts: 1,889
    Does the building owner pay for heat or is there a method in place to bill each unit individually? I own a single story 8 unit and when I built it, decided that each unit needs individual control and each is monitored by a basic hour meter coupled with flow rates and deltas from the radiant manifolds and flowmeters. It ends up within a few bucks every month once I got it dialed in. Primitive, and requires me to stop in once a month to read and record the meters but whatever, I'm happy with it and would do it again. That is setup with parallel return and a single Magna with Honeywell zone valves in the hallway outside each unit (so I don't need to fight for entry) and TA balancing valves. Yes, I still have tenants that keep their thermostat at 85 degrees while their windows are open, but at least they're paying for it instead of me or the neighbors.

    That said, in your case with baseboard, I would absolutely set it up with a ZV in (or outside of) each unit versus in the mechanical room and a single delta P circ. Diagnostics are far easier with controls at the unit IMO. Most of my jobsite experience is hospitals which are obviously different than apartments, but at the same time pretty similar. With baseboard, controls are always in the ceiling or behind the element cover. Tenants are sketchy though as a rule, and tend to find ways to wreck stuff so I like to keep everything possible out in public domain instead of in the unit for them to destroy
    Intplm.
  • Intplm.
    Intplm. Member Posts: 1,882
    Henry said:

    I did a school with 80 classrooms. Each classroom had a vandal proof Danfoss thermostatic valves. It is piped reverse return with constant circulation. The modcon is piped primary secondary. It is the second year, and everyone is happy. Most apartment blocks here are reverse return with constant system pump or pumps. Here is a 100 unit apartment block 1.5 million in heat and a 500 feeding 3 119 gallon storage tanks. This one has no control in each apartment as most of our apartment blocks except the high en units. No complaints from anyone over this colder winter. The VWH just developed a leak between the heat exchanger and pan due to the gasket. It will be fixed this week.

    I did a dorm renovation a few years back. Used the point of use Danfoss thermostatic valves. Did not use the Vandal proof ones as you describe above. The owner Regretted that decision. Ended putting them in at a later date. They are a excellent valve and a great idea to use under these circumstances.
    @Henry
    Nice neat work. Good looking job.
    Henry
  • Tom_133
    Tom_133 Member Posts: 883
    Ok guys I have the heat loss and pipe design done, but I am struggling on the pump because I am not sure I am doing the Head calculations correctly.


    Here is what we got.

    I have 50' 3" copper, 2-3"90
    this goes up to the ceiling of the first floor where I will put in a 3x2x2 tee. Then feeding the first and second floor 2" copper main, that will consist of 2-2" 90's and 220' of 2" copper with 48 through tees, they will feed 24 zones of heat, with 3/4" hepex that at the longest run will be 180' each zone all will have 2 ball valves, 1 zone valve and 1 balance valve.

    the 2nd floor ceiling will have a 2" main with 22 through tees, and the same on each zone with about 130' of hepex. I would like to run 11/2" main on the second floor but the head seems to go up too much

    the 2" main on the first floor that heats the first and second floor needs 34 gpm and the 2nd floor needs 20 gpm.

    I may not have made this situation as clear as you may need, but I keep coming up with 27 feet of head, at 180 degrees. Am I way off?


    Thanks all for the help.
    Tom
    Montpelier Vt
  • EBEBRATT-Ed
    EBEBRATT-Ed Member Posts: 15,453
    So your total flow looks like 54 gpm, why 3"? Your way down on the low end for 2 1/2". The first floor could be 2" @34gpm and the second floor could be 1 1/2" @20 gpm. need the feet of pex and baseboard and size and fittings for the loop furthest away from the boiler if that is the loop with the most resistance.

    Seems like you would need more fittings on the main then 4 elbows you have to do supply and return
  • Tom_133
    Tom_133 Member Posts: 883
    Thanks Ebebratt-Ed, so the number of 90's is correct. I come up to the first floor ceiling in 3" because 3"pipe and fittings are much easier to get locally, and as far as I saw it was not that much different in price. I come up to the top of the first floor in 3, put in the 3x2x2 tee aimed toward my location and then go 10' out to the hallway and put in one 90, that points down the hallway 100' then a cap, the return does the same thing.

    Also, I was only doing third floor in 2" because my calculations keep telling me the head will be a lot greater in 1.5" pipe so if I do it in 2" the 2x3/4 bronze propress tees will be cheaper then 1.5x3/4 propress tees, and my head drops so I can go with a a smaller pump.

    Getting an accurate number on this head is important to have, thats why I am asking. Lets call the longest 3/4 Hepex loop 200' I am not thinking it will be but just in case.

    Tom
    Montpelier Vt
  • Tom_133
    Tom_133 Member Posts: 883
    Also, that 3/4" hepex will be assumed at 2.5gpm thats my biggest heat load, all of this is sized for 180 degrees. I came up with 6.39 of head for that load. Its the mains I am struggling to get the head for.
    Tom
    Montpelier Vt
  • EBEBRATT-Ed
    EBEBRATT-Ed Member Posts: 15,453
    I am getting:
    50' 3" cop
    2 3" 90s
    1 3x2x2 tee all at 54 gpm total head =1.2'

    2" 220 feet of 2" copper
    48 tees (flow on run)
    2 2" 90s flow at 34 gpm total head=15'

    same as above for the other floor with a flow of 20 gpm=5.8'

    So1.2' for the 3" (double this for supply and return)=2.4'
    2 zones (take the highest zone) (I assumed pipe and fittings are for supply & return) =15'
    pex (using your 6.9') =6.9'

    Total 24.3'

    add for any valves, boilers, air separator, flow checks etc

    what I did was just pipe and fittings

    what I came up with is probably on the high side
  • Tom_133
    Tom_133 Member Posts: 883
    Thanks Ebebratt-Ed

    I was hoping for less. I really wanted to use 2- VR-15 two just for redundancy. But I may need to go to a VR20 unless someone sees a better way to Pope it to keep the head down? Split them into two zones and run up to the floors in a little bigger pipe then downsize?
    Tom
    Montpelier Vt
  • EBEBRATT-Ed
    EBEBRATT-Ed Member Posts: 15,453
    There almost no loss in the 3" because it's oversized now. The circuit with the highest resistance is the 2" zone at 34 gpm
  • Tom_133
    Tom_133 Member Posts: 883
    Thanks again, I need to go back and look at the numbers to see how to pipe it most cost effectively.

    Just for my own understanding, when doing the math on the head, I would take the 3" loop head (as well as all the fittings, valves, etc) and add it to the 2" loop and the 1.5 loop then add the head of the longest loop of pex?

    Or just use the largest head value on the copper loops and add the pex loops head to that?

    I have read over my modern hydronic book a lot, but I almost need a step by step example thats very similar to mine to really get it.

    Thanks for the patience everyone I am close.
    Tom
    Montpelier Vt
  • EBEBRATT-Ed
    EBEBRATT-Ed Member Posts: 15,453
    No you take the resistance of the 3" pipe and fittings both supply and return. Then take the 2" loop and the 1 1/2" loop both supply and return and compare the resistance of the two loops an d pick the one with the most head including the longest run of pex on that loop.

    Thought you were using 2" on both loops?
  • Tom_133
    Tom_133 Member Posts: 883
    I probably will, just wrote it that way to show the difference to you. The viega 2x3/4 propress bronze tee seems like the way to go and then just NPT from there.
    Thanks again, seems like the new taco 1915E will fit my needs well
    Tom
    Montpelier Vt