Willis Heating System

[fixitflav]

Would a solid fuel back boiler upstairs heat a tank downstairs?

I wouldn't think so, but if somebody's tried it, the proof of the pudding....

To save me reading the whole thread, what is the advantage of the Willis system? Where does the heat come from?

 

[EFLImpudence]

To save me reading the whole thread, what is the advantage of the Willis system?

It's just an alternative method as far as I can see.

Where does the heat come from?

It is a self contained immersion heater.

 

[Harry Bloomfield]

My cylinder is made of copper, this is a good conductor, so why does it not move the heat from the top to the bottom of the tank?

We have already established that the heat, will not pass down, through the water, due to stratification. While copper will conduct the heat down beyond the boundary, the copper is quite thin, so the conduction will be minimal.

 

[JohnW2]

No, a Willis, can only heat up the water, above the level of the Willis bottom inlet pipe.

Do you mean 'above the level of the bottom of the Willis heater'? If so, that's what I'vv been saying all along, but some seem to disagree.

That can be much lower than a vertical immersion heater reach.

As I have said repeated, at no point have I been thinking about or writing about 'vertical immersion heaters'.

Obviously, the lower the viscosity, the more fluid, the more easily it will rise, and flow from the Willis cylinder, to the main cylinder.

Indeed ('qualitatively) - but, as I implied, I believe that the change in viscosity of water with changing temp is so trivial as to be irrelevant to this discussion.

 

[JohnW2]

No!

I'm glad you agree with me.

An immersion heater, operating in the actual main cylinder, can only heat the water ABOVE the element location.

Exactly what I've always been saying.

A Willis system is able to heat the water in the main cylinder, irrespective of the height/length of the element, The Willis, given enough time, will heat all the water in the main cylinder, as far down as the bottom (cold) Willis connection.

If I understand you correctly, that is, again, what I have been saying all along - that, just as with a horizontal immersion, a Will heater can heater water in the main cylinder below the level of the Wallis heater.

 

[JohnW2]

I am a bit confused with all the different replies and with whom to agree.

Than makes two of us, including in relation to some of the comments that the authors describe as "obvious"?

I would say that at first glance this does not look possible:

So would I.

However, perhaps it is just not coloured accurately. .... For example perhaps nearly ALL the water in the Willis should be pink and indeed pinker - i.e. hotter and less dense - than the water in the cylinder by the time it has been moved so that circulation will be maintained - albeit slowly. ....

Yes, I would say that's how the diagram should have been coloured, but that doesn't alter many failure to understand how it is possible that the depicted system could 'work'. In particular, I'm finding it hard to see how your 'levelling' argument could explain how it would work, because I would have thought that the 'circulation' would stop once one got to this point....

Would a solid fuel back boiler upstairs heat a tank downstairs?

My intuition would certainly have said 'no' (well 'not significantly')

 

[Harry Bloomfield]

As I have said repeated, at no point have I been thinking about or writing about 'vertical immersion heaters'.

Which has no relevance, because it makes no difference. An immersion heater, can only normally heat the water to the lower limit of its element. However, a Willis system, can heat water down to the lower level of its bottom pipe.