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Fornax · 06-30-13, 01:19 PM

Hi All,

A while back I discovered that the HX-core in my HRV is not as efficient as I expected it to be and I found the cause. It comes down to the choice of material.

The plates are made of aluminium. Even worse, the plates are made of relatively thick aluminium, 1mm (1/25"). They conduct heat very well, which is a good thing when you want to transfer heat from one surface to the other surface. But heat will also spread out from any point on the plate throughout the plate in all directions.
That is a good thing if you are building a heatsink to cool a CPU and you want to transport the heat away.
In a heatexchanger you want to transport the heat on any given location only to the other side of the surface on that spot, you do not want to transfer the heat over the surface of the plate to another location.

Aluminium HX-cores are still a good idea if you can:
- make the material thin enough
- make the air move fast enough, say 5m/S
but now you need to:
- overcome pressure loss by using more powerfull fans
- higher airspeeds produce more noise, either live with that or deal with it in another way.

I have been playing with the calculator that can be downloaded from www.heatex.com and their HX-cores do the same, at lower airspeeds they are less efficient, reaching a maximum at a certain point and then declining again.

So what I would like is a heatexchanger build from some sort of plastic, but I find that hard to find in my neighbourhood, or else it is as expensive as aluminium.

And then I found the solution, see next post : )

06-30-13, 01:19 PM	#419
Fornax Helper EcoRenovator Join Date: Oct 2012 Location: Beuningen (Gld), the Netherlands Posts: 64 Thanks: 4 Thanked 19 Times in 16 Posts	Hi All, A while back I discovered that the HX-core in my HRV is not as efficient as I expected it to be and I found the cause. It comes down to the choice of material. The plates are made of aluminium. Even worse, the plates are made of relatively thick aluminium, 1mm (1/25"). They conduct heat very well, which is a good thing when you want to transfer heat from one surface to the other surface. But heat will also spread out from any point on the plate throughout the plate in all directions. That is a good thing if you are building a heatsink to cool a CPU and you want to transport the heat away. In a heatexchanger you want to transport the heat on any given location only to the other side of the surface on that spot, you do not want to transfer the heat over the surface of the plate to another location. Aluminium HX-cores are still a good idea if you can: - make the material thin enough - make the air move fast enough, say 5m/S but now you need to: - overcome pressure loss by using more powerfull fans - higher airspeeds produce more noise, either live with that or deal with it in another way. I have been playing with the calculator that can be downloaded from www.heatex.com and their HX-cores do the same, at lower airspeeds they are less efficient, reaching a maximum at a certain point and then declining again. So what I would like is a heatexchanger build from some sort of plastic, but I find that hard to find in my neighbourhood, or else it is as expensive as aluminium. And then I found the solution, see next post : )