Calculating power dissipated in a heat exchanger

  • Thread starter Thread starter SgtSixpack
  • Start date Start date
Click For Summary
SUMMARY

The discussion focuses on calculating power dissipation in a heat exchanger for a PC watercooling loop. The user highlights discrepancies in using liters per hour (LPH) to determine mass in kilograms, emphasizing the need for specific density and heat capacity values for their non-distilled cooling fluid, Mayhems X1. The correct formula for mass-rate calculation is provided, which requires the mass-density of the fluid. Users are advised to contact the manufacturer for accurate specifications to ensure proper calculations.

PREREQUISITES
  • Understanding of fluid dynamics and heat transfer principles
  • Familiarity with mass-density and heat capacity concepts
  • Basic mathematical skills for unit conversion
  • Knowledge of PC watercooling systems and components
NEXT STEPS
  • Research the mass-density and heat capacity of Mayhems X1 cooling fluid
  • Learn about the thermodynamic properties of various cooling fluids
  • Explore advanced calculations for heat exchangers in PC cooling systems
  • Investigate the impact of fluid properties on cooling efficiency
USEFUL FOR

PC builders, watercooling enthusiasts, thermal engineers, and anyone involved in optimizing cooling systems for computers.

SgtSixpack
Messages
3
Reaction score
1
TL;DR
Is this calculation right?
2024-0804 Rad Heat Calc-C.png

I want some help in figuring out any flaws in these calculations. I was given this picture but I was looking into it and found some things which are either wrong or don't apply to my watercooling loop (for my PC).

First thing I notice is that litres per hour divided by 3600 (hours to minutes) gives units in kg.

I don't know if it maters (since I can't find specific numbers on heat capacity of the fluid) but I'm not using distilled water but this stuff (it was £20 when I bought it):
https://mayhems.store/mayhems-x1-clear-premixed-watercooling-fluid-5-litres.html

For background information here is the thread where I got the picture from:
https://forum.aquacomputer.de/weite...t/?s=d38a467e13100c26b8c0293df1023b395dbbd769

Also appologies if this is the wrong section of the forums.
 
Engineering news on Phys.org
SgtSixpack said:
TL;DR Summary: Is this calculation right?
The "flowchart" shown is a correct (but cumbersome) way to calculate the cooling capacity based on the simple formula in the gray box, which I enlarge here for clarity:
1744986155606.png

Note though that the specific figures used there (kg/sec = liters-per-hour/3600 and Cp = 4.178) apply only to distilled water. To use the formula with your cooling fluid, you'll need to contact the manufacturer to obtain the proper values of mass-density and heat-capacity for that particular product.
 
Thanks for the response. I'm still not happy with the first part of the calculation.

LPH/(a constant)
can't end up as kg from my limited knowledge of mathematics.

To find the mass in kg, one would need something like density of water. Guess I'm right/wrong according to google:

"One litre of water has a mass of almost exactly one kilogram when measured at its maximal density, which occurs at 3.984 °C. It follows, therefore, that ⁠1/1000⁠ of a litre, known as one millilitre (1 mL), of water has a mass of about 1 g, while 1000 litres of water has a mass of about 1000 kg (1 tonne or megagram)."
 
SgtSixpack said:
I'm still not happy with the first part of the calculation.
LPH/(a constant)
can't end up as kg from my limited knowledge of mathematics.
To find the mass in kg, one would need something like density of water.
That's exactly right. Use the formula:$$\text{mass-rate}\left(\text{kg/s}\right)=\text{mass-density}\left(\text{kg/m}^{3}\right)\times\text{volume-rate}\left(\text{m}^{3}\text{/s}\right)$$For water, the mass-density is ##\text{997}\approx\text{1000}\,\text{kg/m}^3##, but as I said, you'll need to contact your supplier to find the mass-density of your cooling fluid.
 
Thanks for explaining that. I can't like your post unfortunately.
 
  • Like
Likes renormalize

Similar threads

Replies
1
Views
3K
  • · Replies 5 ·
Replies
5
Views
6K
  • · Replies 23 ·
Replies
23
Views
7K
Replies
2
Views
2K
  • · Replies 9 ·
Replies
9
Views
3K
  • · Replies 7 ·
Replies
7
Views
3K
  • · Replies 2 ·
Replies
2
Views
2K
  • · Replies 2 ·
Replies
2
Views
3K
  • · Replies 7 ·
Replies
7
Views
2K
Replies
4
Views
3K