In terms of viscosity, this Shell fluid almost looks like sludge at 0 C (32 F). Also the heat capacity and thermal conductivity are low (compared to water).
I would design this system to prevent freezing (-30 C, as you specified) using an alcohol/water mixture. Minimize the distillation issue with a low percentage glycol that shifts the fraction (distillation) point higher in temp.
Am pulling physical chemistry labs out of my brain from more decades ago that I prefer to mention.
The major issue is freezing. Due to the low operating temp, an organic fluid appears way to viscous in the range of temps you operate in.
You also have huge summer insolation rates and you may want to put in a back-up circulation pump to prevent summer heat stagnation and a vapor expansive calamity (if you use alcohols).
VERY interesting problem.
Steve
__________________
consulting on geothermal heating/cooling & rational energy use since 1990
Last edited by stevehull; 06-20-14 at 08:30 AM..
|