Chilled Water Piping Material
Chilled Water Piping Material
(OP)
Has anyone used CPVC or PEX for chilled water piping?
Among other issues:
I am trying to find a surface temperature of PEX and CPVC with 45 deg water and no insulation without breaking out my heat transfer textbook.
Among other issues:
I am trying to find a surface temperature of PEX and CPVC with 45 deg water and no insulation without breaking out my heat transfer textbook.





RE: Chilled Water Piping Material
Naturally, it goes without saying that despite a full-time spotter, and extensive staking of the lines' locations, we nicked the lines with a backhoe, not even that hard, and quickly flooded the foundation excavation, costing two weeks' work on that, and another weeks' work to repair the lines.
RE: Chilled Water Piping Material
Approximate surface temp should be obtainable if you can get the R value of the pipe, the thickness. Temperatures should be known.
Chris
RE: Chilled Water Piping Material
Outside diameter 110mm
Wall thickness 8.2mm
Chilled Water 6degC
Surrounding Air 22degC
Draught 0.5m/s
CPVC surface temperature 12.3degC
PEX surface temperature 8.8degC
(CVPV thermal conductivity 0.15W/mK, PEX thermal conductivity 0.46W/mK).
Brian
RE: Chilled Water Piping Material
RE: Chilled Water Piping Material
If PEX were used at all it would be for branches only to the fan coils.
I have seen it for water source heat pumps. But I have a hard time seeing insulating PEX as practical.
RE: Chilled Water Piping Material
A brief look in catalogues:
REHAU offers Pe-Xa pipe for heating and sanitary cold water, which means it can be normally used for fan-coils..
HENCO offers multilayer pipe, inner pipe is PE-Xc, and outer pipe is Alumine - explicitely specified for cooling and heating.
Sometimes I use PP-R as well.
All this pipes have light insulating caracteristics, if you have time you can make input of pipe data in some insulation software and find that couple of mm less insulation thickness is needed compared to steel pipes.
Usuallly I don't take chances for condensation prevention -I presume ca 5% lower critical air humidity and that's it.
RE: Chilled Water Piping Material
CPVC is ok. Watch them like a hawk so they don't use PVC.
RE: Chilled Water Piping Material
RE: Chilled Water Piping Material
sometimes CPVC does not like too much propylene, saw a geothermal job go south when the comcentrations for freeze protection required made the cpvc joints leak
Take the "V" out of HVAC and you are left with a HAC(k) job.
RE: Chilled Water Piping Material
Have a look here:
http://www.aquatherm-uk.com
They do a pipe-system that is designed for chilled water, without using insulation.
They should have a tool for you that calculates if condensation will occur under your specific conditions.