Split Loop System Questions

Brad White

in terms of pipe sizing. As with any series-loop system your radiation has to be increased in size to compensate for water temperature drop in direction of flow, I think you know that.

Splitting the loop lessens this effect on each side of the house and you know this also.

That said, each supply series is sized for flow at temperature drop (2-4 FPS velocity). When these join, the "homerun" is sized for the sum of both flows.

nedjinski

split loop systems

I want to build a simple split loop series system for baseboard heaters.
I need some advice on system pipe sizes when using a split loop.

nedjinski

brad -

thanks for the reply.

in my design, the "homerun" is sized up accordingly most of the way back to the pump except for a section that has to run through a solar water tank heat exchanger, whose coils are the same size as the split loops - will this "bottleneck" negate the advantages of the larger "homerun" leg?

Mike T., Swampeast MO

Check the ratings of the HX coil to ensure that your design system flow is in the acceptable range. Then include the added head loss of the coil at your design rate when sizing the circulator.

Ken_40

Ned

It would be easier to simply make the HX a secondary and thereby "independent" zone - allowing the trunk flow to merely pass by and be drawn in/out as desired.

Brad White_9

Mike and Ken have you covered

If in series with your flow, you need to take into account the solar HEX. As Ken said though, if in parallel it is not a factor and can be on-line or off-line as necessary. A little more complicated initially but will not impose an effect on one system to the other.

One way to set it up using the same system circulator is to install a line-size motorized zone valve in the main homerun with two tees; one tee on either side of it. The tees will branch to the HEX of course.

When the solar tank can contribute, (sensed by, say, a line aquastat make on rise), the valve would be indexed closed thus forcing flow through the HEX.

Of course this will affect your system flow at that time. So long as the circulator can handle it, I think it is simplest. (Flow can vary a good deal and only affects your average water temperature at that time. You can cut flow by 50% and still get about 90% of capacity.

Such a deal.

nedjinski

split loops

thanks for the feedback - here is a diagram of my proposed system - maybe that will make my idea clearer.


http://img258.imageshack.us/my.php?image=3480hydronicsof9.jpg