Repurpose NVR case fan to CPU fan - easy!

[MakeItRain]

Dahua actually has a pretty decent 60mm fan installed in their NVR for expelling heat. But if you're not using all four hard drives like I am, then you're much better off re-purposing the 60mm fan and mounting it on top of the CPU itself.

This default fan location is mounted so far away from the motherboard that I began to wonder its effective usefulness. I find that I can repurpose this fan right on top of the CPU since the CPU has no fan. I am also no longer using the original NVR case because it is way too big and I will never have four hard drives. I have since transplanted all the components into a ITX case.

The fan is a 4-pin PWM and is dynamically adjustable by the NVR firmware when it needs more cooling or less. On boot-up, the fan is definitely loud, but shortly when it boots into the OS, it becomes pretty silent. Without the fan, the CPU heatsink can get pretty very warm but not burning hot. WIth the fan on top, it is nearly ice cold now.

The bolts are M3 x 45mm.

 

[TonyR]

I'm not doubting your findings that the CPU runs cooler, but I'm not sure I personally would put that much effort into that unit unless I was sentimentally attached to it. But we all have our projects.

I am puzzled, however, with the results after your mod. Before your mod, the fan would either create some pressure or suction depending on its rotation, either pulling in cold air from the non-fan side and pushing the warm air out the fan side or vice-versa (pulling in air from fan side and exhausting it out non-fan side). This would exchange the air in the case, the heatsink fins would radiate its heat into that space.

Now, there's no pressure or vacuum applied to the case, the air just runs around inside with some getting out, some coming in.....enough, I guess. Also, I understand you put it into a smaller case. And lastly, by the fan's rotational arrow and airflow direction arrow cast into the fan's side (3rd image), I'd venture to say it would cool even better if the fan pulled air AWAY from the heat sink rather than INTO the heatsink....maybe not. Who knows?

Thanks for sharing!

 

[MakeItRain]

I'm not doubting your findings that the CPU runs cooler, but I'm not sure I personally would put that much effort into that unit unless I was sentimentally attached to it. But we all have our projects.

I am puzzled, however, with the results after your mod. Before your mod, the fan would either create some pressure or suction depending on its rotation, either pulling in cold air from the non-fan side and pushing the warm air out the fan side or vice-versa (pulling in air from fan side and exhausting it out non-fan side). This would exchange the air in the case, the heatsink fins would radiate its heat into that space.

Now, there's no pressure or vacuum applied to the case, the air just runs around inside with some getting out, some coming in.....enough, I guess. Also, I understand you put it into a smaller case. And lastly, by the fan's rotational arrow and airflow direction arrow cast into the fan's side (3rd image), I'd venture to say it would cool even better if the fan pulled air AWAY from the heat sink rather than INTO the heatsink....maybe not. Who knows?

Thanks for sharing!

In my 20 years of building PCs ever since I was in the 7th grade, it is my experience and understanding, that of all the CPU's heatsink/fan combinations I have seen, both aftermarket and Intel and AMD.. that the fan blows air downward into the heatsink. But this is how all the big name companies do it and I believe it has the most benefit to the heatsink itself.

I believe the rest of the other components on the motherboard do not benefit much from extra cooling from what I can tell. But yes, the ITX case does have another fan to suck hot air hot.

The stock Dahua NVR enclosure has no fan blowing into the case. The stock PSU power supply is also blowing air out and sucking air from within.

If you look at auto manufacturers, they do not suck hot air from inside a hot car to keep the occupants cold. They blow cold air into the cabin right?

 

[usaf_pride]

You may have gained CPU cooling, but you probably have hurt the PoE cooling (if you have a PoE NVR). You may also have inadvertently raised the temperature of nearby components as the heatsink discharge air is being blown across the motherboard components. I'm not saying it is a bad idea, but the heatsink is designed as part of the system. My NVR does have a case fan.

Auto AC is a closed loop system even with the recirculate button is off. The generated cabin heat is transferred thermodynamically through the condenser and discharged outside the space, thus cooling the returning air. If you put a fan in a closed box, it will always be the same temperature not matter how much air it moves (you could make an argument that it would actually get warmer due to the friction of the air). That is why there are case fans on computers (or if they don't have them, the cooling is designed to flow the air in and out of the computer using ducting).

The fans on CPU's blow down because they can guarantee and even temperature across the entire heatsink. The same could be accomplished by pulling the air away from the CPU if you controlled the incoming air temperature on all sides.