Overall piping length in swh systems

[organic farmer]

We had an apartment building that was 3 stories tall. The furnaces for all units were in the basement. I had to replace the baseboard heating loops for all apartments. Apartments on the third floor were harder to pump water up into their loop, at the first, and for chasing the air bubbles out.

But once the loop was done, all the air bubbles were gone, and it was circulating, the circulating pump itself works no harder on the third floor units than they do for the second floor or first floor units.

For every foot of rise there is an equal foot of fall. It is a closed loop.

You can make a closed loop that is totally flat horizontal, and another loop that in the middle has to go up 40 foot and back done again. If both of these loops are the same length, diameter, and neither have any sharp bends, than resistance to flow will be the same.

[bernard]

Thank you peakbagger.

How many stories do you have? Basement and ground floor?
Where is the storage tank located? In the basement or ground floor (that's first floor in US I imagine). Are your collectors located on the roof?

[peakbagger]

Unless its drainback system it really doesn't matter as long as you keep friction loss in mind. If the friction loss exceeds the pump curve then you either need a new pump or go with larger diameter pipe. I probably have 60 feet in my loop which I piped up in 3/4" and during three seasons the DC pump has too much capacity so I get a lot of noise. Once the weather cools down and the glycol viscosity goes up it quiets right down and eventually it stops flowing as the head loss exceeds the pumps capacity. One of those slick new electronic commutated pumps with a built in flow control might work real slick for a AC system but my DC system is far too primitive, just a solar panel a pump and a on off controller that runs the pump when the panels are warmer than the tank.

[inetdog]

bump

[bernard]

There is one thing that I am curious of:
What are some rule of a thumb, or approximate overall pipe run length in residential swh systems?

I know it may be difficult to answer this question, as it depends on a lot of factors: whether or not a swh system's storage is right next to the collector (ICS, thermosyphon), or located in the basement.
I also understand that it depends on the number of floors, position of a collector (on the roof, on the ground) and some other factors too.

But for example what are some approximate values of piping lengths for ground floor + one/two floor houses with collectors on the roof, and storage tank in the basement or ground floor?
50 feet? 100 feet?
Can it be said for example: if your storage tank is located on the lowest floor, and collectors are on the roof then add the 20 feet of pipe length run (overall in both directions) per each story. Then add another 10 feet for the pipes on the roof.
Of course this is an assumption based on a straight shot, from the storage to the collectors.

Just to clarify: I am not interested in losses of energy due to piping, nor in pipe diameters. I am just interested in the total pipe run length.

Thank you for the reply, and I apologize if it is difficult to answer this question.