What temperature is the water in a wc system?

[JonJ678]

I know it's going to be a range from ambient to very hot depending on whats emptying heat into it and what is removing heat, but roughly what is the range?

If you empty 400W into the system and remove 400W from it, its presumably going to sit, on average, at ambient temperatures. The radiator efficiency increases with temperature, and it takes time for heat to diffuse. I take it this accounts for temperature being above ambient.

But what values are normal?

 

[JonJ678]

No, it's not - for a constant heat output it'll reach a state of stable, dynamic equilibrium at a temperature where the rate of heat transfered to the air from the radiators/other loop components equals the rate your components and pump produce it. For the radiator in a closed loop to work (transfer the heat from water to air) there must be a temperature difference between water temperature and ambient air temperature. Since there's a difference in water in and water out of the radiator, the average water temperature will depend on the amount of heat removed by the radiator for the given airflow, water flow rate to replace cooled water with warmer water and maintain air-water delta T, efficiency in transferring heat energy to fin/pipe cooling surface and from those surfaces to the air passing through the radiator. These combine to give a C/W value - the temperature difference between ambient air and water temperature for a given set-up given the wattage going into the loop from compaonents and pump heat output.

I think that's right, if not I'm sure others can explain better.

From reading the above a couple of times, I think its what I said but in considerably more detail and preceded by 'no, it's not'. I didn't make myself very clear at all though.

The efficiency of a radiator where water temperature equals ambient is zero, it moves no heat at all. Hence higher temp water than ambient required, how much higher depends on thermal coefficients/air flow rate/water flow rate/conductivities of the fluids and of course on the wattage dumped into the flow. <--clarification of first post

I think I prefer your description as it is much clearer, thank you very much for posting it. Particularly appreciate the description of C/W.

I didn't realise temperatures were maintained that close to ambient. Good news. I take it that more radiators stands a good chance of lowering temperatures, but the improvement will fall off rapidly with the number introduced?

If water is maintained at roughly ten above ambient (say) then it looks like the thermal conductivity of the waterblock for the cpu is very important, as it doesn't get to eject heat into the ambient air. Cheers guys, shall continue researching this.

 

[JonJ678]

Wow. Cheers all, I've learnt a lot from the above. Decided to try water sooner rather than later, but put it in a new thread for fear of stopping any further useful information emerging here

 

[JonJ678]

Ill input only to say that copper will go very very black when heated enough. Its a good idea to check the thermal conductivity and solubility of copper II oxide, as I'm pretty sure the former will be low and the latter high.

The black coating which forms will also flake off if you let it thicken too much. Producing an even coating with a blowtorch won't happen easily, I want to suggest heating it electrically but this will do nasty things to that months electricity bill. If done nicely this would be beautiful