The Homemade Heat Pump Manifesto

stevehull · 11-25-15, 05:37 PM

AC - you make us laugh!

The take home point is that you cannot have turbulent flows in any of the distribution fields as Len has described. I am wondering about just his supply and return pipes. In fact, I doubt if there ever is anything but laminar in vertical loops as well.

But that is my perspective based on some years of education, field and laboratory work.

You may want to consider the inlet diameter ratio where pipe velocity decreases in a parallel pipe network. In general, at about ten diameters downstream, turbulent flow becomes laminar. This is an accepted rule of thumb (is still on the EIT PE test) and is certainly accepted in straight pipes. A "loopy" horizontal field is still going to look pretty much like a straight pipe from a hydraulic perspective as the ratio of the loop radius to pipe diameter is so large.

This wound mean that all our loop fields (vertical or horizontal are likely laminar and would be very poor at transferring BTUs (your opinion).

Oh my - another deletion from the thread!!

We can continue to have fun with this - and expand the number of replies to the manifesto - or we can have more salient discussions . . . .

Steve
aka SH

11-25-15, 05:37 PM	#10
stevehull Steve Hull Join Date: Dec 2012 Location: hilly, tree covered Arcadia, OK USA Posts: 826 Thanks: 241 Thanked 165 Times in 123 Posts	AC - you make us laugh! The take home point is that you cannot have turbulent flows in any of the distribution fields as Len has described. I am wondering about just his supply and return pipes. In fact, I doubt if there ever is anything but laminar in vertical loops as well. But that is my perspective based on some years of education, field and laboratory work. You may want to consider the inlet diameter ratio where pipe velocity decreases in a parallel pipe network. In general, at about ten diameters downstream, turbulent flow becomes laminar. This is an accepted rule of thumb (is still on the EIT PE test) and is certainly accepted in straight pipes. A "loopy" horizontal field is still going to look pretty much like a straight pipe from a hydraulic perspective as the ratio of the loop radius to pipe diameter is so large. This wound mean that all our loop fields (vertical or horizontal are likely laminar and would be very poor at transferring BTUs (your opinion). Oh my - another deletion from the thread!! We can continue to have fun with this - and expand the number of replies to the manifesto - or we can have more salient discussions . . . . Steve aka SH __________________ consulting on geothermal heating/cooling & rational energy use since 1990