# Further reflections on watercooling

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I got some good feedback regarding my earlier "reflections on watercooling" piece, and I thought of a few things I'd missed, so here's some more dankwisdom. Take it for whatever it's worth. Please feel encouraged to send in further data for these tables, assuming you got the info directly from the manufacturer, or rigorously acquired it yourself.

• Knowing the volume of your components is useful for working the heat equations, for knowing how much coolant you'll need (particularly relevant when using concentrates), and also for determining completion when filling or draining. Unfortunately, this information isn't generally published. I've measured some components using a graduated cylinder at 22℃. The cylinder was labeled at 2mL increments, so no more than 2mL of precision can be assumed. This is unfortunate, as some components hold not much more than that.
Component Volume (mL)
Hardware Labs XFLOW 240 radiator 90
Hardware Labs GTR 360 radiator 320
Hardware Labs GTS 360 radiator 130
EKWB Aorus Master monoblock 45
EKWB EK-Vector waterblock 50
EKWB Quantum Kinetic FLT 240 reservoir+pump 265
DiyHZ sensor 4
Monsoon Series Two reseroir+pump 300
EKWB XTOP Dual D5 pump 35
aquacomputer highflow NEXT sensor 8

For those of you who dropped out before the first grade, the volume of your (cylindrical) tubing can be calculated by multiplying the length of the tubing by pi by half the inner diameter squared. Area of a circle is πr², r is a radius (half of your inner diameter), and the volume is then area times length. If it's not obvious, this works no matter how you might curve or bend your tube.

Compression fittings negligibly effect the total volume. If you wanted to model their impact, each tube ought be considered shorter by twice the length of the barb (the extrusion inserted into your tube), indicating the volume occupied by the barb. The barb's volume in this region is then equal to that length times, once again, the area of the barb's interior. Using calipers, I measured the inner diameters of some compression fittings intended for 0.5in (12.7mm) inner diameter tubing:

Barb model Inner diameter (mm) Length (mm) Volume (mL) Δ (mL)
EKWB EK-AH 10.9 10.0 0.933 0.334
EKWB Quantum Torque 8.75 10.0 0.601 0.666

The non-linearity of the r² term is obvious here: the Quantum Torque inner diameter is 80.3% of the EK-AH's, but the total volume is only 64.4%. Either way, 10mm of the tubing is 1.267mL, so you're talking ¾ or ½ of that in the fitting. Assuming half-inch tubing, you can thus subtract 0.666mL for every Quantum Torque compression fitting, or 0.334 for every EK-AH. A 200mL reservoir would represent almost 600 times this latter value.