A TIM C/W number.

[Les]

Originally Posted by unregistered

is this difference measureable ?

Think not.
Probably 95% Specific Heat and possibly 99-105% Density of water (here and here
Worst case :

[Les]

Same model as here
Imput values :
Water :- Cg=4171w/kg, Density=998.2kg/m^3, Cond=0.599w/m*c, Kinematic Viscosity=1.006e-6 m/s, (Calculated Thermal Diffusivity= 1.430e-7m^2/s, Calculated Prandtl No=6.99)
15% Antifreeze:- Cg=3962.w/kg, Density=998.2kg/m^3 Cond=0.545w/m*c,Kinematic Viscosity= 4.353e-6 m/s, (Calculated Thermal Diffusivity= 1.378e-7m^2/s, Calculated Prandtl No= 31.59)
Values possibly a bit ugh but......

[BillA]

0.004-5 °C/W diff @ 4lpm ?
seems a bit much (but I've never used 15% - or even 0.5% antifreeze)
HydrX is 0.3% ethylene glycol when mixed per inst

I have chillers with antifreeze, next fill I'll make a 15% soln and we can ck the theory

[Les]

Originally Posted by unregistered

0.004-5 °C/W diff @ 4lpm ?
seems a bit much (but I've never used 15% - or even 0.5% antifreeze)

That is value my sums give.
Incoherent's measured value is more like 0.003 - Incoherent's data

[BillA]

hmmm
you have more confidence in your calcs ?

[Les]

No, but think they ballpark.

[Incoherent]

Originally Posted by Les

That is value my sums give.
Incoherent's measured value is more like 0.003 - Incoherent's data

I'll clean some of this data up later using an average of many measurements for the water only.
Also I am not sure about the antifreeze. The Swedish part of the product description (which I can read) makes no mention of strength but the danish (which I cannot read properly) section mentions "60-100%" I don't quite know what this means. If the solution is already lower than 100% perhaps the numbers make some sense.
There is the problem of my flowrate calculation. A fairly small shift (left or right on the graph) could affect the values. Flow measurement is a problem. Some methods work well at low flowrates, some at high, none work well over the whole range. Been bugging me for a while.
Some more work is clearly needed. I will try and improve the resolution of my pressure drop sensor. Currently it is about 0.12kPa, way too low resolution for the lower flowrates.

Not this weekend though. I'm off to Riga, Latvia.