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GPM design to maintain 2-4 feet per second

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McSteamer22
McSteamer22 Member Posts: 23
I have a home, 2 zones, both 1 1/2 mains, direct return with all 1/2 inch branches to cast iron baseboards. total home load is 130k btuh, 1st floor is 70k, second floor is 60k. I have not yet calculated my ft of head I need to overcome. my question is can I design my gpm flow rate on only needing 7 gpm and 6 gpm through each zone, but I know my ft per sec would be too low, my system sizer says I need to move atleast 13 gpm through 1 1/2 steel pipe at the minimum and that gets me to 2.05 ft per sec. I guess I'm looking for confirmation on weather I size gpm on load only or whatever pipe I'm walking into dictates my gpm.

thanks
William from CT
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Comments

  • Ironman
    Ironman Member Posts: 7,379
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    You size on load and the necessary delta T at design temp.
    Bob Boan
    You can choose to do what you want, but you cannot choose the consequences.
    Rich_49
  • Jamie Hall
    Jamie Hall Member Posts: 23,446
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    Pipe size will give you a range of flow rates -- the general recommendation is the 2 to 4 feet per second. Then the delta T will give you the amount of heat delivered. It's a tradeoff -- more flow, smaller delta T. Less flow, more delta T.
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
    McSteamer22
  • Rich_49
    Rich_49 Member Posts: 2,766
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    FPS is not and has never been a proxy for system performance . Lest we all forget that when that 2-4 fps recommendation was written we did not have the air removal capabilities that we do now either . Funny that if you look at many manufacturers provide tables which show that for a majority of the time , flow through loops would rarely get to the mythical 2 - 4 fps .
    For example , we would not reach 2 fps in a 1/2 " line until it needed .6 gpm . Most of my designs have several loops for an area and rarely do I see flows of .6 gpm . As I look at a design I am working on right now I see 1.7 gpm / 4 loops = .425 gpm per , 1.2 gpm / 3 loops = .4 gpm per , .65 gpm / 2 loops = .325 gpm per . Highest fps in these examples would be about 1.7 fps . Should we even worry about main piping , has it not been stated by others in the industry that short fat headers are a good idea ? I have done long fat headers and can state without hesitation that they also work and lessen piping losses .

    You'll be fine flowing 6 & & gpm through those mains and will suffer less piping loss , Relax
    You didn't get what you didn't pay for and it will never be what you thought it would .
    Langans Plumbing & Heating LLC
    732-751-1560
    Serving most of New Jersey, Eastern Pa .
    Consultation, Design & Installation anywhere
    Rich McGrath 732-581-3833
    Gordy
  • EBEBRATT-Ed
    EBEBRATT-Ed Member Posts: 15,629
    edited January 2018
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    Just keep in mind that low velocity will inhibit air removal. Big pipe is not a problem , if you can get the air out. Have vents in the right locations will be important. Think about where air could trap.
  • newagedawn
    newagedawn Member Posts: 586
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    130000 btu is 1 1/4 supply and return for 6 ft of head for 100 ft and 13 gpm, so 1 1/2 will work they probably oversized for head loss through the pipe as it works around your house so all radiators get hot about the same time, you need a taco 007 or any delta t pump like an grundfoss alpha, taco makes one also but i forget the name, where in CT, if your in my area i can come look at it
    "The bitter taste of a poor install lasts far longer than the JOY of the lowest price"
    McSteamer22
  • hot_rod
    hot_rod Member Posts: 22,262
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    Low velocity will inhibit air removal especially in vertical down flowing lines. Under low flow conditions the water flowing down is not always sufficient to push the air along with it. Air rises up through the flow of water and traps in high points. Noise is also often associated with inadequate flow velocity in regards to air elimination.

    A good air separator is critical, but only works at 90% efficiencies if the air is getting to the device.

    I would be sure to add some high point air vents in systems with low flow velocities under those conditions.

    Also at some low flow condition, heat transfer will slow to an unacceptable level. Some look to the Reynolds number for that prediction.

    Air removal issues and lack of adequate heat transfer will help you determine if you flow is too low.

    Some good reading about flow velocity, etc in this journal.

    https://www.caleffi.com/sites/default/files/coll_attach_file/idronics_16_na_0.pdf
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • Rich_49
    Rich_49 Member Posts: 2,766
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    What entity wrote this ?

    " ________ air separators continuously remove entrained air in hydronic systems with very high separation efficiency . the amount of air removed from a system varies depending on fluid velocity and temperature , as illustrated in the graph below , atb 4. feet per secondfluid velocity , all air artificially introduced into the circuit is eliminated by the ____________ air separator .

    Any small amount which remains is then gradually eliminated during normal system operation . In conditions where the fluid velocity is SLOWER or the temperature of the fluid is higher , the amount of air separated is even GREATER "

    We have spent decades improving air elimination devices . is it not about time we started teaching where they should be placed and designing systems for specific conditions that promote better and most efficient heat transfer and Exergy . We should not be moving fluid at any greater rate than is necessary to heat a space at any given time . Place air elimination devices at opportune places and make your best effort at varying flows to best meet the requirements for the largest portion of a heating season . How bout that ?

    Myself and a few others have been doing things like this that fly in the face of ancient knowledge or , rather , opinion . Funnny thing is that after following Bob Rohr's and others advice about air elimination I realized that you can run at these low , prohibited numbers and NOT suffer air issues in any system . Funnier thing is ny already pretty good efficiency numbers got much better . Still waiting for all those comfort complaints also , kinda feeling like the Maytag Repairman . I'll be here waiting for the calls from my peers to solve their problems though , happens all the time . Hope you all caught that , I listened to Bob years ago and applied that knowledge .

    Again , as I stated above . If you utilize low flow rates in your mains air elimination can be increased , you'll also have less piping loss . You will still for a large portion of the season have transitional to lower turbulent flows in the portions of your system where it is desirable , the business end , emitters .

    Be water , be air , go through your systems and eliminate air where it will be a problem and start designing systems for 2200 hours per year instead of 125 hours per year , you'll be amazed at the results .
    You didn't get what you didn't pay for and it will never be what you thought it would .
    Langans Plumbing & Heating LLC
    732-751-1560
    Serving most of New Jersey, Eastern Pa .
    Consultation, Design & Installation anywhere
    Rich McGrath 732-581-3833
    GordyMcSteamer22
  • hot_rod
    hot_rod Member Posts: 22,262
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    Actually an air separator will work great at 0 fps flow rate, that is not the question or point I made.

    The point is the air needs to get back to the separator. At low velocity, under 2 fps air may not be pushed down, from upper levels to the separation device if it is located below the piping and emitters.

    A clear piping demo clearly shows how air rises up a pipe with low flow velocity downward. That is why air vents are installed on cast iron radiators, air traps in the upper portion, it never gets pushed out of that high point, low velocity zone.

    No ancient knowledge involved, just basic science air in water rises, hotter air rises faster, even within a fluid stream.
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
    McSteamer22
  • Rich_49
    Rich_49 Member Posts: 2,766
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    and my point was that it is more important to keep the FPS up in the smaller lines feeding and returning from emitters . The Ops original question was about FPS in his 1 1/2 mains being too low , not the 1/2 lines which your answer refers to . If I misunderstood that part please let me know .

    but I still stand by proper placement of elimination devices and lower flows even in loops and smaller diameter lines to make a better system . If you are removing much of the air in the lower velocity portions of the system , it is unlikely that air will be a problem . Most of the systems I design also have manifolds above the emitters , loops . those manifolds usually have air elimination also . retrofit systems vary in what I am capable of doing based on any number of factors . Again , i have not had an air problem in a system that was initially filled and purged properly .

    You didn't get what you didn't pay for and it will never be what you thought it would .
    Langans Plumbing & Heating LLC
    732-751-1560
    Serving most of New Jersey, Eastern Pa .
    Consultation, Design & Installation anywhere
    Rich McGrath 732-581-3833
  • hot_rod
    hot_rod Member Posts: 22,262
    edited January 2018
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    As I read it he is asking about 6 gpm in an 1-1/2" pipe. The equates to under 2 fps. He may not get good air removal if those are vertical runs to the upstairs.

    High point, float type vents would help if applicable.
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • hot_rod
    hot_rod Member Posts: 22,262
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    flow chart
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • Rich_49
    Rich_49 Member Posts: 2,766
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    I have a home, 2 zones, both 1 1/2 mains, direct return with all 1/2 inch branches to cast iron baseboards. total home load is 130k btuh, 1st floor is 70k, second floor is 60k. I have not yet calculated my ft of head I need to overcome. my question is can I design my gpm flow rate on only needing 7 gpm and 6 gpm through each zone, but I know my ft per sec would be too low, my system sizer says I need to move atleast 13 gpm through 1 1/2 steel pipe at the minimum and that gets me to 2.05 ft per sec. I guess I'm looking for confirmation on weather I size gpm on load only or whatever pipe I'm walking into dictates my gpm.

    thanks
    William from CT

    After reading this again it certainly looks as if the mains are in the basement and probably horizontal with 1/2 risers , branches to the emitters . Maybe the OP could verify .

    That chart would support the fact that 6 & 7 gpm respectively are both sub 2 FPS . Agreed ? Could we also agree that moving water that is doing no work goes against all things efficient ?
    ( Exergy )
    You didn't get what you didn't pay for and it will never be what you thought it would .
    Langans Plumbing & Heating LLC
    732-751-1560
    Serving most of New Jersey, Eastern Pa .
    Consultation, Design & Installation anywhere
    Rich McGrath 732-581-3833
  • hot_rod
    hot_rod Member Posts: 22,262
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    Hmmm, I would say all moving water does work, even a flowing river is has energy.

    In some cases engineers design district system, in-ground, for low flow laminar conditions. The intent is to lessen losses to the ground.

    Once the piping to the loads takeoff they design for turbulent conditions.

    So the low flow, below 2 fps is doing work as is the above 2 fps flows in the distribution and emitters.
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • Paul48
    Paul48 Member Posts: 4,469
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    The work done by the water, that transfers energy, above what is required, can only be described as inefficiency.
    Rich_49McSteamer22
  • HomerJSmith
    HomerJSmith Member Posts: 2,468
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    Rich, my understanding from the data that I have read is that turbulent flow transfers heat energy thru a pipe wall better than laminar flows. I would want laminar flow in the delivery piping and turbulent flow in the heat emitter to maximize the transfer of BTU's where it is needed. Higher flow rates leads to turbulent flow as well as obstructions to the flow. Over sized headers within reason are a good thing because of the low flow rate and that leads to laminar flow, but does present a problem in vertical runs without some device that can remove accumulated air in a high point.

    My perturbation is that so many pictures posted here with Mod/Con boilers are all piped with 3/4" lines.
    SuperTech
  • Paul48
    Paul48 Member Posts: 4,469
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    My limited understanding, is that laminar flows cannot be achieved with current piping technology, at any flow rate. The lab found that any imperfections, or disturbances within the piping created eddies or turbulence, at any flow rate.
    Rich_49McSteamer22
  • Zman
    Zman Member Posts: 7,573
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    Boiler and distribution piping in the 2-4 fps range is a good idea. It requires less head energy and the pipes last a good long time.
    As eluded above, don't try to get pex radiant loops in that range. You will waste a ton of circ energy with no significant performance increase.
    "If you can't explain it simply, you don't understand it well enough"
    Albert Einstein
    GordyMcSteamer22
  • HomerJSmith
    HomerJSmith Member Posts: 2,468
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    Paul48, of course, you're right. It's the degree of turbulence that matters and where that turbulence occurs.

    Rick says, " Could we also agree that moving water that is doing no work goes against all things efficient ? ( Exergy ) " I not so sure that I can agree with that statement. I think, it is what constitutes your definition of 'work' and what constitutes your definition of 'efficient'. Efficiently is subjective and relative in nature. It is an applied standard based upon an applied standard.

    Thermodynamically 'work' is the change one system makes on another system. The Universe operates between dis-equilibrium and equilibrium. It's this principle of seeking equilibrium that makes 'work' possible. Man creates machines that create dis-equilibrium to effectively make 'work'. The airplane wing is such a machine. Air passing over it creates high pressure on the underside and low pressure on the top side. Nature tries to equalize the pressure differences. The result is called "lift".

    A river flowing under it own head is also creating 'work'. It is changing the system called Earth by eroding Earth, think Grand Canyon, and transferring heat energy collected during the day to the cooler atmosphere at night.

    Moving water in a header by its very nature is doing 'work'. Beside eroding the pipe, the fact that it is moving from a high pressure state to a low pressure state, seeking equilibrium, means 'work' is being done.

    The boiler creates 'work' by imparting heat energy to the water, the pump does 'work' by creating hi and low pressures in the piping, and the moving water does 'work' by transferring that heat energy to the atmosphere. Once equilibrium is reached 'work' stops until something else happens that creates dis-equilibrium.
  • HomerJSmith
    HomerJSmith Member Posts: 2,468
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    The great wonder of the Universe is that it is constantly creating dis-equilibrium while at the same time seeking equilibrium.
  • jumper
    jumper Member Posts: 2,289
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    Decades ago hydronic pipe in larger buildings was designed 6 fps. See Hanson Hydronics Handbook. Years later it was decided that that speed was too high for longevity. Sometimes the envelope is pushed for glycol/chilled water to reduce insulation work.
  • hot_rod
    hot_rod Member Posts: 22,262
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    Paul48 said:

    My limited understanding, is that laminar flows cannot be achieved with current piping technology, at any flow rate. The lab found that any imperfections, or disturbances within the piping created eddies or turbulence, at any flow rate.

    Which lab, Paul?

    Reynolds number from 0- 2300 predicts flow is laminar. There are plenty of online calculators available to calculate Reynolds numbers. I would guess copper tube or pex would be a smooth walled flow path?

    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
    McSteamer22
  • HomerJSmith
    HomerJSmith Member Posts: 2,468
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    hot rod, the only time, water flow, is truly laminar is in a vacuum without anything in contact with the water molecules. In a vacuum with a column of falling water, all the water molecules move at the same rate, true laminar flow.

    The Reynolds number is relative to the % of laminar vs turbulent flow. Water flowing in a pipe will always have turbulent flow and it always will. The boundary where the water molecules meet the pipe wall will always be turbulent because of friction and any mineralization on the pipe wall will increase this turbulence.

    This is what Paul48 and I had in mind.

    We use to call this friction loss, now pressure loss. Any flow in a pipe will be a combination of turbulent flow and laminar flow.

    John Siegenthaler, PE, in his book "Modern Hydronic Heating", I believe has a picture of how the drag of water molecules on the pipe boundary look like. Its shape is like that of a nose cone or a bullet. The flow at the boundary is slower than the center of the pipe. This dis-equilibrium creates turbulence.
  • HomerJSmith
    HomerJSmith Member Posts: 2,468
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    Paul48 probably should have phrased his statement as true laminar flows. I assumed that is what he meant.
    McSteamer22
  • hot_rod
    hot_rod Member Posts: 22,262
    edited January 2018
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    hot rod, the only time, water flow, is truly laminar is in a vacuum without anything in contact with the water molecules. In a vacuum with a column of falling water, all the water molecules move at the same rate, true laminar flow.

    The Reynolds number is relative to the % of laminar vs turbulent flow. Water flowing in a pipe will always have turbulent flow and it always will. The boundary where the water molecules meet the pipe wall will always be turbulent because of friction and any mineralization on the pipe wall will increase this turbulence.

    This is what Paul48 and I had in mind.

    We use to call this friction loss, now pressure loss. Any flow in a pipe will be a combination of turbulent flow and laminar flow.

    John Siegenthaler, PE, in his book "Modern Hydronic Heating", I believe has a picture of how the drag of water molecules on the pipe boundary look like. Its shape is like that of a nose cone or a bullet. The flow at the boundary is slower than the center of the pipe. This dis-equilibrium creates turbulence.

    Siggy presented a 2 hour seminar on this concept at AHR last week, here are a few slides. The "streamline" flow I think you are talking about is still considered laminar.

    The temperature of the fluid plays a big part also. 3/4 copper with 120° fluid would need .57 gpm to reach 4000 Reynolds.

    At 50° 1.33 gpm
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
    McSteamer22
  • HomerJSmith
    HomerJSmith Member Posts: 2,468
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    Nice slides, hot rod, I'm going to download them for quick reference, any chance for a link to the seminar?
  • HomerJSmith
    HomerJSmith Member Posts: 2,468
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    Were off topic, but it's interesting.

    hot rod, how do you create laminar flow in a hydronic system? If you can create turbulent flow in a system you should be able to create laminar flow in a system. Please, don't tell me, you get rid of all the turbulent flows.

    Theoretical constructs that those slides, show, whether true or not, may not be applicable in the real world. I'm not saying that they aren't true, I think they are true, but what I'm saying that the model exists under strict constrictions. There are other destabilizing process at work in real life boiler applications.

    What happens to laminar flow when it hits the impellor of a pump, a 90 deg ell, a side port of a tee, or passes thru a Caleffi dirtmag. How far does turbulent flow have to travel in a straight pipe before it turns laminar? What could cause a laminar flow to become turbulent? These are the things that I would like to know.
    McSteamer22
  • Paul48
    Paul48 Member Posts: 4,469
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    @hot rod

    I was afraid someone would ask. I don't recall. It was a study that someone posted here.
    I don't know how those flows could remain laminar in "real world" conditions. Just looking at the velocity profile on one slide, shows the lower velocity of the water in contact with the tube wall. Now, add in deformities created by fittings and media to remove air from systems, etc., and I don't see it. The whole heat transfer turbulent vs. laminar is very much rooted in common sense. It just seems to be "truer", when drawn on a blackboard. That's my ignorant opinion, and my name is Reynolds.
    McSteamer22
  • Brewbeer
    Brewbeer Member Posts: 616
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    I suspect the answers to some of these questions can be found using calculus.
    Hydronics inspired homeowner with self-designed high efficiency low temperature baseboard system and professionally installed mod-con boiler with indirect DHW. My system design thread: http://forum.heatinghelp.com/discussion/154385
    System Photo: https://us.v-cdn.net/5021738/uploads/FileUpload/79/451e1f19a1e5b345e0951fbe1ff6ca.jpg
  • HomerJSmith
    HomerJSmith Member Posts: 2,468
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    Laminar flow is where all the streamline move parallel to each other, forever, following Newton's first law of motion until acted upon by another force. What's a streamline? What characteristics define a streamline? Is it water molecules following each other in a Conga line? Water molecules have an affinity for each other. Do water molecules move from one Conga line to an adjacent Conga line, according to Newton only if acted upon? Would that be considered turbulence? If one streamline is moving faster than another parallel streamline such as the center of a flow stream moving faster than the outer edges of another flow stream, why doesn't the kinetic energy of the faster stream transfer kinetic energy to the slower stream?

    These are some of the questions that keep me up at nite.
  • HomerJSmith
    HomerJSmith Member Posts: 2,468
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    Calcules, hell, Brewbeer, I can't even spell it.
  • HomerJSmith
    HomerJSmith Member Posts: 2,468
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    Reynolds--Good one, Paul48. I like the way you work.
  • Gordy
    Gordy Member Posts: 9,546
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    Maybe not @HomerJSmith, but you can clearly think it. I like your thoughts.

    Remember there is laboratory controlled experiments, and the real world in which defies such conformity’s. I prefer as some to think real world, because that is what is really happening.

    Taking a snap shot of a section of pipe in a whole system then putting a flow rate to it as being turbulent, or laminar in predicting the outcome of the entire system is just not the real world for the entire system.

    Well designed piping practice, and air elimination location is what is prudent. Keep your flow rates just enough to do the heat transfer the air will follow.



    McSteamer22
  • hot_rod
    hot_rod Member Posts: 22,262
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    Paul48 said:

    @hot rod

    I was afraid someone would ask. I don't recall. It was a study that someone posted here.
    I don't know how those flows could remain laminar in "real world" conditions. Just looking at the velocity profile on one slide, shows the lower velocity of the water in contact with the tube wall. Now, add in deformities created by fittings and media to remove air from systems, etc., and I don't see it. The whole heat transfer turbulent vs. laminar is very much rooted in common sense. It just seems to be "truer", when drawn on a blackboard. That's my ignorant opinion, and my name is Reynolds.

    Mr Reynolds to me :)

    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
    McSteamer22
  • Rich_49
    Rich_49 Member Posts: 2,766
    edited January 2018
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    Paul48 probably should have phrased his statement as true laminar flows. I assumed that is what he meant.

    What we are regularly actually dealing with are flows in Osborne Reynolds transitional regime .

    Homer J Smith . For future conversations let's say that WORK is positive work and desirable . Transferring heat energy to a space which is not the one intended to be heated is inefficient , moving water that is doing no positive work is inefficient . Designing and installing systems is the goal . Maximizing boiler efficiency as well as every segment or aspect of a system is what I am always attempting to achieve .

    Research would also suggest that Reynolds numbers consist of 3 flow regimes , laminar , transitional , and turbulent . In a building where the mythical perfectly sized boiler existed , if you designed evrything perfectly but certain parts of the piping system were sized for turbulent flows the occupants may never be comfortable since the piping would be sized such that heat energy we need in the space to be heated would be being delivered space/s not meant to be heated . Insulation will not even correct this problem . A bit more research would also suggest that Reynolds numbers really should not be used for heat exchange systems having air as the medium which heat energy is being exchanged to . They are more for fluid to pipe wall to fluid or solid material . basically for GSHP systems , heat exchangers , radiant systems , much less for emitters transferring to air as the reservoir . I will search through my machine and post related , supporting documents .

    I don't quote dead guys without having read them myself .
    You didn't get what you didn't pay for and it will never be what you thought it would .
    Langans Plumbing & Heating LLC
    732-751-1560
    Serving most of New Jersey, Eastern Pa .
    Consultation, Design & Installation anywhere
    Rich McGrath 732-581-3833
    McSteamer22
  • HomerJSmith
    HomerJSmith Member Posts: 2,468
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    Rich--" Maximizing boiler efficiency as well as every segment or aspect of a system is what I am always attempting to achieve ."

    This shows that you are a conscientious person who take seriously his responsibility toward his craft and his customers.

    "Work" is neither positive or negative nor desirable or undesirable. It's just plain ole work.

    I was talking about 'work' in the thermodynamic sense and I thought you were using that term in that manner. Work that is positive or desirable is an emotional evaluation, a judgemental call. Nature doesn't give a hoot about anybody's emotions. it just is and we have to work within its constraints.

    Rich, your documents are welcome. I'm also learning and I'm running out of time and there's so much more to learn and I'm panicky that I'll never get it done.

    I will bet that most of the installers in the field don't know what a Reynolds number is, let alone, what a Darcy equation is. I've seen some beautiful installations on Callefi's website and some horrible installation on this website.

    Good work is its own reward and provides a heightened sense of satisfaction that you did your best.
    Rich_49
  • hot_rod
    hot_rod Member Posts: 22,262
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    Were off topic, but it's interesting.

    hot rod, how do you create laminar flow in a hydronic system? If you can create turbulent flow in a system you should be able to create laminar flow in a system. Please, don't tell me, you get rid of all the turbulent flows.

    Theoretical constructs that those slides, show, whether true or not, may not be applicable in the real world. I'm not saying that they aren't true, I think they are true, but what I'm saying that the model exists under strict constrictions. There are other destabilizing process at work in real life boiler applications.

    What happens to laminar flow when it hits the impellor of a pump, a 90 deg ell, a side port of a tee, or passes thru a Caleffi dirtmag. How far does turbulent flow have to travel in a straight pipe before it turns laminar? What could cause a laminar flow to become turbulent? These are the things that I would like to know.


    I have read that underground piping in district systems is designed around laminar flow to keep the temperature losses down.


    Without being Ms Frizzle inside the piping I don't know anyone that could prove or disprove that. A great book series to read to kids, or grandkids, by the way.

    More often I see products, recently at AHR that go inside and outside piping to increase turbulence and heat transfer.
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
    McSteamer22
  • Rich_49
    Rich_49 Member Posts: 2,766
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    These products interest me Bob . Maybe you could post a couple links to them ?
    You didn't get what you didn't pay for and it will never be what you thought it would .
    Langans Plumbing & Heating LLC
    732-751-1560
    Serving most of New Jersey, Eastern Pa .
    Consultation, Design & Installation anywhere
    Rich McGrath 732-581-3833
    Canucker
  • Brewbeer
    Brewbeer Member Posts: 616
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    Convoluted copper is used in high efficiency immersion wort chillers used by homebrewers. Cold water flows through the inside of a coiled length of copper tube, which is immersed into the wort after the boil to chill the hot wort so yeast can be added to start fermentation. Twisting the copper tubing convolutes it, thereby increasing turbulence and heat transfer, which reduces chilling time and decreases the amount of chilling water needed.
    Hydronics inspired homeowner with self-designed high efficiency low temperature baseboard system and professionally installed mod-con boiler with indirect DHW. My system design thread: http://forum.heatinghelp.com/discussion/154385
    System Photo: https://us.v-cdn.net/5021738/uploads/FileUpload/79/451e1f19a1e5b345e0951fbe1ff6ca.jpg
    McSteamer22
  • Rich_49
    Rich_49 Member Posts: 2,766
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    There ya go , fluid / tube / fluid . Reynolds numbers apply . Let's not get lost though debating the same old stuff .. The Ops question was about slow flows in mains , not emitters . Let's also not forget that we got here talking about air removal , which can be done efficiently and effectively with lower flow rates in the portion of the system where we do not particularly want heat transfer .

    i asked a question awhile back .

    What entity wrote this ?

    " ________ air separators continuously remove entrained air in hydronic systems with very high separation efficiency . the amount of air removed from a system varies depending on fluid velocity and temperature , as illustrated in the graph below , at 4. feet per second fluid velocity , all air artificially introduced into the circuit is eliminated by the ____________ air separator .

    Any small amount which remains is then gradually eliminated during normal system operation . In conditions where the fluid velocity is SLOWER or the temperature of the fluid is higher , the amount of air separated is even GREATER "

    Anybody care to take a stab at filling in the blanks or which entity made this statement ?
    You didn't get what you didn't pay for and it will never be what you thought it would .
    Langans Plumbing & Heating LLC
    732-751-1560
    Serving most of New Jersey, Eastern Pa .
    Consultation, Design & Installation anywhere
    Rich McGrath 732-581-3833
  • hot_rod
    hot_rod Member Posts: 22,262
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    Rich said:

    These products interest me Bob . Maybe you could post a couple links to them ?



    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream