Willis Water Heating System

[ericmark]

I have many times tried to find some one with the skill to fit the system, and have failed here in Wales. I look at the solar version which would seems to show it does not need to be 3 kW all the time, however as to how it is all set up, not sure, using a 3 kW element powered from a iboost+ would seem to tick all the boxes, heating in fullness of time the whole tank, but giving hot water quickly, but how is the unit controlled?

My solar can produce 6 kW and the battery has a charge limit of 2 kW so being able to put some energy into the water is good, but at moment 366 watt only, drawing 97 watt from battery. OK winter so central heating running and I can't stop CH boiler from heating the DHW, so only needed in the summer.

It seems the Willis is also used to power under floor heating it is simply a small boiler. Watching youtube it shows a ¾ inch regulating valve at the bottom of the tank, so there seem to be two controls when input wattage is variable there is a valve looking like a gate valve at the base 'A' (¾ inch regulating valve), and 'E' at top is called a temperature sensor, so it seems two methods to control flow when there is a variable input.

However likely better asking in plumbing section, would be interested in finding out more.

 

[Johntheo5]

Dare I ask this then?
I have just read the whole of this thread from start to finish and my head is spinning.

If we had a system say a Willis and the small cylinder containing the immersion heater is mounted substantially lower than the main cylinder (rather similar to a two floor terraced house with a back boiler on the ground floor and the main cylinder on the first floor) then would that substantially change the working principle of the Willis set up??

Theoreticall, yes, as you are increasing the circulating height, the pipes must obviously be very well lagged to maintain the difference in temperatures so density difference, the circulting height is (in the case of a boiler/cylinder), the distance between the centre lines of the boiler and cylinder coil flow&return.
Heres a example, below, good luck with it, but have a good read of post #104

 

[Johntheo5]

I have many times tried to find some one with the skill to fit the system, and have failed here in Wales. I look at the solar version View attachment 337879 which would seems to show it does not need to be 3 kW all the time, however as to how it is all set up, not sure, using a 3 kW element powered from a iboost+ would seem to tick all the boxes, heating in fullness of time the whole tank, but giving hot water quickly, but how is the unit controlled?

My solar can produce 6 kW and the battery has a charge limit of 2 kW so being able to put some energy into the water is good, but at moment 366 watt only, drawing 97 watt from battery. OK winter so central heating running and I can't stop CH boiler from heating the DHW, so only needed in the summer.

It seems the Willis is also used to power under floor heating View attachment 337882 it is simply a small boiler. Watching youtube it shows a ¾ inch regulating valve at the bottom of the tank, so there seem to be two controls when input wattage is variable View attachment 337884there is a valve looking like a gate valve at the base 'A' (¾ inch regulating valve), and 'E' at top is called a temperature sensor, so it seems two methods to control flow when there is a variable input.

However likely better asking in plumbing section, would be interested in finding out more.

The Willis system you show is the solasyphon which has a heating coil in a cylinder instead of a heating element but they are not great as the coil heating area is only around 0.2m2, the dedicated solar coil heating surface in a HW cylinder is ~ 1.0m2., however they do save installing a cylinder with a dedicated solar coil.
The bit of advice I gave someone re the iboost was purely re pipe sizing and installing a pipestat etc but I do know its working quite well and the iboost will just divert whatever excess power is available to the Willis, once the cylinder reaches temperature then then the pipestat cuts out the power and the excess power is then diverted back to the grid, (no battery in this system).

 

[ericmark]

My father-in-law fitted a solar water heater, not voltage like mine, and said how good it was, until he had a smart meter fitted and he had no hot water. So I went to fix it, and found the solar was doing near to nothing, reason he thought it was saving money, they had removed the immersion heater as used the supply to work solar panels pump.

Reason no hot water, when smart meter fitted the pilot flame went out, so no central heating boiler, getting the so called experts to look at the system, it would just take chill off the water, at peak of summer.

So we went for electric solar panels, and also fitted an iboost+ which does work, but the immersion heater only heats about the top 9" of the tank, so need either a longer immersion heater or the Willis system. The latter in theroy can heat whole tank, but the question is if when not getting a full 3 kW it will still work.

So this is the question, does that sensor ensure the flow varies according to the immersion output?

'E' at top is called a temperature sensor

I am not a good plumber, so next question is can I find some one in Wales to fit it for me? Would they know what they are doing?

I note @Johntheo5 is from Cork, so likely knows far more about the Willis system to a Welsh plumber, seems only the Irish can get their head around the system, Welsh plumbers seem to be tick in comparison!

 

[Johntheo5]

Never saw a Willis down here, probably fairly popular in the North where it was invented, there is a bit of interest now though due to solar PV.