Further reflections on watercooling - revision history

Dank at 16:12, 2 May 2022

2022-05-02T16:12:25Z

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	* Adding more power increases flow rates more as the total power level increases. I.e. going to 50% from 25% PWM adds less flow than going from 75% to 100%. This is contrary to my intuition.		* Adding more power increases flow rates more as the total power level increases. I.e. going to 50% from 25% PWM adds less flow than going from 75% to 100%. This is contrary to my intuition.

	And one final, probably controversial point, from my own experiments: '''~~modern~~ waterblocks are very effective even at low flow rates'''. According to my two sensors, I have never managed to exceed 1L/min in my loop, even when using two D5 pumps. My loop is quite large, and climbs over a meter through the height of my very large case, but this still seems a lower flow rate than one might expect from two D5 pumps (admittedly at low power settings). Common hearsay is that one wants at least 0.5G/min (1.9L/min); I rarely manage even half of this. Regardless, my temperatures are excellent, both when measured absolutely at the heat generating sources and when the coolant is measured relative to ambient. Optimizing for flow seems a foolish errand, and ought be of only secondary concern when designing a loop.		And one final, probably controversial point, from my own experiments: '''quality waterblocks are very effective even at low flow rates'''. According to my two sensors, I have never managed to exceed 1L/min in my loop, even when using two D5 pumps. My loop is quite large, and climbs over a meter through the height of my very large case, but this still seems a lower flow rate than one might expect from two D5 pumps (admittedly at low power settings). Common hearsay is that one wants at least 0.5G/min (1.9L/min); I rarely manage even half of this. Regardless, my temperatures are excellent, both when measured absolutely at the heat generating sources and when the coolant is measured relative to ambient. Optimizing for flow seems a foolish errand, and ought be of only secondary concern when designing a loop.

	'''previously: "[[Reflections_on_watercooling\|reflections on watercooling]]" 2022-04-17'''		'''previously: "[[Reflections_on_watercooling\|reflections on watercooling]]" 2022-04-17'''

	[[Category:Blog]]		[[Category:Blog]]

Dank at 16:09, 2 May 2022

2022-05-02T16:09:11Z

← Older revision		Revision as of 16:09, 2 May 2022
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	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. You can use this same reasoning to calculate the (very small) volume loss at each fitting juncture—just use the inner diameter of the threading.		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. You can use this same reasoning to calculate the (very small) volume loss at each fitting juncture—just use the inner diameter of the threading.

	* When completely idled, a modern processor ought be using only a handful of watts. This is insubstantial heating at the surface area of an integrated heat spreader / waterblock. Ergo, an idled processor ought report temperatures ~~roughly equal to~~ the coolant's temperature. If an idle processor reports temperatures more than ~~a degree~~ or ~~two~~ over the coolant's temperature (modulo any systematic error in your sensors), you have most likely fucked up application of the thermal paste. If they don't, you most likely haven't; congratulations.		* When completely idled, a modern processor ought be using only a handful of watts. This is insubstantial heating at the surface area of an integrated heat spreader / waterblock. Ergo, an idled processor ought report temperatures not much greater than the coolant's temperature; this certainly ought be a constant. If an idle processor reports temperatures more than ten degrees or so over the coolant's temperature (modulo any systematic error in your sensors), you have most likely fucked up application of the thermal paste. If they don't, you most likely haven't; congratulations.

	* Sensors are notoriously inaccurate. You can explore their relative systematic inaccuracy by placing them immediately after one another in series (this can of course be changed later). Sensors like to be level relative to gravity.		* Sensors are notoriously inaccurate. You can explore their relative systematic inaccuracy by placing them immediately after one another in series (this can of course be changed later). Sensors like to be level relative to gravity.

Dank at 11:30, 2 May 2022

2022-05-02T11:30:05Z

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	* It is natural that pockets of air will persist in your system after filling it. Microbubbles will eventually diffuse naturally out of the system, but larger bubbles need your help. Air, being lighter than water, naturally moves to the local top of a section of the loop. It is thus advisable that your reservoir (and filling point) be as high in the loop as possible. Rotate the machine while the pump is running, attempting to coax the bubble to your reservoir (or any point where you can allow air to leave). Eventually, the air will leave (often with an audible burp), and your coolant level will fall. Top off the coolant (this is why you wanted the air to leave via your refill point), and live happy.		* It is natural that pockets of air will persist in your system after filling it. Microbubbles will eventually diffuse naturally out of the system, but larger bubbles need your help. Air, being lighter than water, naturally moves to the local top of a section of the loop. It is thus advisable that your reservoir (and filling point) be as high in the loop as possible. Rotate the machine while the pump is running, attempting to coax the bubble to your reservoir (or any point where you can allow air to leave). Eventually, the air will leave (often with an audible burp), and your coolant level will fall. Top off the coolant (this is why you wanted the air to leave via your refill point), and live happy.

	If you calculated your total volume accurately, and track how much fluid you've added, you can know to your satisfaction when you've eliminated all air. This can be useful when you have opaque volumes (like most radiators—I've never seen a transparent radiator, don't know why, it would be cool) at the top of your loop. With that said, it's pretty difficult to get your total volume calculation accurate to more than a few mL, which can be a significant amount of air if it's in e.g. a waterblock.		If you calculated your total volume accurately, and track how much fluid you've added, you can know to your satisfaction when you've eliminated all air. This can be useful when you have opaque volumes (like most radiators—I've never seen a transparent radiator, don't know why, it would be cool. I guess you can't get highly thermally conductive clear materials?) at the top of your loop. With that said, it's pretty difficult to get your total volume calculation accurate to more than a few mL, which can be a significant amount of air if it's in e.g. a waterblock.
	* [https://en.wikipedia.org/wiki/Pascal%27s_law Pascal's principle] states that a pressure change at any point in a confined incompressible fluid is transmitted through the fluid such that the change acts everywhere. This has various effects:		* [https://en.wikipedia.org/wiki/Pascal%27s_law Pascal's principle] states that a pressure change at any point in a confined incompressible fluid is transmitted through the fluid such that the change acts everywhere. This has various effects:
	** Opening a horizontal port lower than other fluid in the loop will see fluid leave that port until the heights are equalized, once again making a big mess.		** Opening a horizontal port lower than other fluid in the loop will see fluid leave that port until the heights are equalized, once again making a big mess.

Dank at 11:12, 2 May 2022

2022-05-02T11:12:13Z

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	* '''Your loop is never a vacuum'''. This is good, as nature would otherwise abhor it. Assuming you're not actively asphixiating, you're working in at atmosphere of air, and air fills the regions of your loop not filled by water. In particular, when you've first hooked everything up and before you've begun to fill the loop with water, your loop is filled with the equal volume of air. Water cannot exist where air already does, and thus air must leave your system for water to enter. There are three ways to accomplish this:		* '''Your loop is never a vacuum'''. This is good, as nature would otherwise abhor it. Assuming you're not actively asphixiating, you're working in at atmosphere of air, and air fills the regions of your loop not filled by water. In particular, when you've first hooked everything up and before you've begun to fill the loop with water, your loop is filled with the equal volume of air. Water cannot exist where air already does, and thus air must leave your system for water to enter. There are three ways to accomplish this:
	** Use a powerful vacuum pump to evacuate the system. Contact your local HVAC technician to explore this route.		** Use a powerful vacuum pump to evacuate the system. Contact your local HVAC technician to explore this route.
	** Ensure air can leave from the same place you're adding coolant. This can be accomplished via filling with a graduated cylinder, a filling bottle, or anything else with less area than the inlet, and ought purge any air below the inlet. ~~Noticeably~~, a funnel attached to a fitting, screwed into the inlet, will generally block the entire area and not allow air to leave.		** Ensure air can leave from the same place you're adding coolant. This can be accomplished via filling with a graduated cylinder, a filling bottle, or anything else with less area than the inlet, and ought purge any air below the inlet. Notably, a funnel attached to a fitting, screwed into the inlet, will generally block the entire area and not allow air to leave.
	** Ensure air can leave from somewhere else, some outlet. This ought purge any air below the outlet. Once coolant reaches the level of the outlet (or the inlet), further filling will expel coolant, rather than air. This is also known as "making a mess", and is undesirable.		** Ensure air can leave from somewhere else, some outlet. This ought purge any air below the outlet. Once coolant reaches the level of the outlet (or the inlet), further filling will expel coolant, rather than air. This is also known as "making a mess", and is undesirable.
	It is hopefully obvious from this that your filling inlet ought be as high in the loop as possible, and essentially must be in order to quickly remove air. This ought be considered when designing your loop. If it's impossible to get it there, rotate your case while filling.		It is hopefully obvious from this that your filling inlet ought be as high in the loop as possible, and essentially must be in order to quickly remove air. This ought be considered when designing your loop. If it's impossible to get it there, rotate your case while filling.

Dank at 09:03, 2 May 2022

2022-05-02T09:03:17Z

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	</center>		</center>
	Some properties are immediately apparent. I'm surprised EKWB didn't point these out in their writeup, but hey, that's why I'm here:		Some properties are immediately apparent. I'm surprised EKWB didn't point these out in their writeup, but hey, that's why I'm here:
	* Adding even nine 90° adapters is, at all reduced power levels, more than overcome by a ~~25%~~ increase in power.		* Adding even nine 90° adapters is, at all reduced power levels, more than overcome by a an increase in power to the next 25% level.
	* Across all four measured power levels, adding eight adapters (nine total) cuts a little over 23% of the flow relative to a single adapter. This is remarkably consistent: 76.1%, 76.7%, 76.5%, and 76.5%. Of course, these are absolutely larger as flow increases: the 23.7% reduction at 100% represents a loss of 350L/h, whereas the 23.9% reduction at 25% represents a loss of only 59L/h.		* Across all four measured power levels, adding eight adapters (nine total) cuts a little over 23% of the flow relative to a single adapter. This is remarkably consistent: 76.1%, 76.7%, 76.5%, and 76.5%. Of course, these are absolutely larger as flow increases: the 23.7% reduction at 100% represents a loss of 350L/h, whereas the 23.9% reduction at 25% represents a loss of only 59L/h.
	* As more fittings are added, the reduction per fitting decreases. This correlates perfectly with our statement above: ''the obstruction to flow presented by any unit results in a greater loss of flow for greater flow rates''.		* As more fittings are added, the reduction per fitting decreases. This correlates perfectly with our statement above: ''the obstruction to flow presented by any unit results in a greater loss of flow for greater flow rates''.

Dank at 08:51, 2 May 2022

2022-05-02T08:51:09Z

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	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.		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:		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 barbs. The barbs' volume in these regions is then equal to that length times, once again, the area of the barbs' interior. Using calipers, I measured the inner diameters of some compression fittings intended for 0.5in (12.7mm) inner diameter tubing:
	<center>		<center>
	{\| class="wikitable sortable"		{\| class="wikitable sortable"

Dank at 08:49, 2 May 2022

2022-05-02T08:49:03Z

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	\| DiyHZ sensor \|\| 4		\| DiyHZ sensor \|\| 4
	\|-		\|-
	\| Monsoon Series Two ~~reseroir~~+pump \|\| 300		\| Monsoon Series Two reservoir+pump \|\| 300
	\|-		\|-
	\| EKWB XTOP Dual D5 pump \|\| 35		\| EKWB XTOP Dual D5 pump \|\| 35

Dank at 08:41, 2 May 2022

2022-05-02T08:41:29Z

← Older revision		Revision as of 08:41, 2 May 2022
Line 69:		Line 69:
	* '''Your loop is never a vacuum'''. This is good, as nature would otherwise abhor it. Assuming you're not actively asphixiating, you're working in at atmosphere of air, and air fills the regions of your loop not filled by water. In particular, when you've first hooked everything up and before you've begun to fill the loop with water, your loop is filled with the equal volume of air. Water cannot exist where air already does, and thus air must leave your system for water to enter. There are three ways to accomplish this:		* '''Your loop is never a vacuum'''. This is good, as nature would otherwise abhor it. Assuming you're not actively asphixiating, you're working in at atmosphere of air, and air fills the regions of your loop not filled by water. In particular, when you've first hooked everything up and before you've begun to fill the loop with water, your loop is filled with the equal volume of air. Water cannot exist where air already does, and thus air must leave your system for water to enter. There are three ways to accomplish this:
	** Use a powerful vacuum pump to evacuate the system. Contact your local HVAC technician to explore this route.		** Use a powerful vacuum pump to evacuate the system. Contact your local HVAC technician to explore this route.
	** Ensure air can leave from the same place you're adding coolant. This can be accomplished via filling with a graduated cylinder, a filling bottle, or anything else with less area than the inlet, and ought ~~eliminate~~ any air below the inlet. Noticeably, a funnel attached to a fitting, screwed into the inlet, will generally block the entire area and not allow air to leave.		** Ensure air can leave from the same place you're adding coolant. This can be accomplished via filling with a graduated cylinder, a filling bottle, or anything else with less area than the inlet, and ought purge any air below the inlet. Noticeably, a funnel attached to a fitting, screwed into the inlet, will generally block the entire area and not allow air to leave.
	** Ensure air can leave from somewhere else, some outlet. This ought ~~eliminate~~ any air below the outlet. Once coolant reaches the level of the outlet (or the inlet), further filling will ~~eliminate~~ coolant, rather than air. This is also known as "making a mess", and is undesirable.		** Ensure air can leave from somewhere else, some outlet. This ought purge any air below the outlet. Once coolant reaches the level of the outlet (or the inlet), further filling will expel coolant, rather than air. This is also known as "making a mess", and is undesirable.
	It is hopefully obvious from this that your filling inlet ought be as high in the loop as possible, and essentially must be in order to quickly remove air. This ought be considered when designing your loop. If it's impossible to get it there, rotate your case while filling.		It is hopefully obvious from this that your filling inlet ought be as high in the loop as possible, and essentially must be in order to quickly remove air. This ought be considered when designing your loop. If it's impossible to get it there, rotate your case while filling.

Dank at 08:40, 2 May 2022

2022-05-02T08:40:52Z

← Older revision		Revision as of 08:40, 2 May 2022
Line 113:		Line 113:
	Some properties are immediately apparent. I'm surprised EKWB didn't point these out in their writeup, but hey, that's why I'm here:		Some properties are immediately apparent. I'm surprised EKWB didn't point these out in their writeup, but hey, that's why I'm here:
	* Adding even nine 90° adapters is, at all reduced power levels, more than overcome by a 25% increase in power.		* Adding even nine 90° adapters is, at all reduced power levels, more than overcome by a 25% increase in power.
	* Across all four measured power levels, adding eight adapters (nine total) cuts a little over 23% of the flow relative to a single adapter. This is remarkably consistent: 76.1%, 76.7%, 76.5%, and 76.5%.		* Across all four measured power levels, adding eight adapters (nine total) cuts a little over 23% of the flow relative to a single adapter. This is remarkably consistent: 76.1%, 76.7%, 76.5%, and 76.5%. Of course, these are absolutely larger as flow increases: the 23.7% reduction at 100% represents a loss of 350L/h, whereas the 23.9% reduction at 25% represents a loss of only 59L/h.
	* As more fittings are added, the reduction per fitting decreases. ~~I would think this due to there being less restriction as flow rate decreases, but that contradicts~~ our statement above. ~~Interesting!~~		* As more fittings are added, the reduction per fitting decreases. This correlates perfectly with our statement above: ''the obstruction to flow presented by any unit results in a greater loss of flow for greater flow rates''.
	* Adding more power increases flow rates more as the total power level increases. I.e. going to 50% from 25% PWM adds less flow than going from 75% to 100%. This is contrary to my intuition.		* Adding more power increases flow rates more as the total power level increases. I.e. going to 50% from 25% PWM adds less flow than going from 75% to 100%. This is contrary to my intuition.

Dank at 08:36, 2 May 2022

2022-05-02T08:36:56Z

@@ Line 80: / Line 80: @@
 ** You can't fill above the filling point without rotation or pumping.
 ** You want your draining point at the bottom of your loop.
 '''previously: "[[Reflections_on_watercooling|reflections on watercooling]]" 2022-04-17'''
 [[Category:Blog]]