complicated solar switch arrangement

[ajn9000]

Does anyone have any suggetsions on which gear would be best for this arrangement. Need to use a solar switch to feed an immersion heater and 3 zones of UFH. Outline attached. Feed from the solar switch needs to be routed to the UFH zones or the immersion heater - controlled from a room thermostat. If directed to the UFH there need to be 4 modes: i) cycle through all 3 zones with an adjustable period, ii) to 1 of 3 zones. There needs to be a main enable/disable control/switch for the solar switch and a daylight sensor. If disabled or dark, the UFH would be switched to a conventional arrangement to be controlled using 3 programmable thermostats. Anyone done anything like this?

 

[snowhead]

Turning the Immersion heater on when your on Solar generation I can understand.

But what's the benefit with the Underfloor?

 

[sean_ork]

Forcing the UFH to make use of the PV heated water is sensible, but I suspect it'll have to be a fair size array, and a custom controller (certainly for the cycling requirement)

I'm assuming these will be immersions within a TS rather than a conventional cylinder.

 

[davesparks]

Use a solar immersion controller such as the solar Iboost, it has a switched output along with the variable power output.

 

[Worcester]

Personally would always use an ImmerSun for lots of reasons
The controls can be quite easily done depending upon which ufh room stats you have
I'd use an immersun with heatmiser controls and a number of changeover contactors.
If you don't understand my response, or can't research it yourself then don't attempt it and instead get it designed properly.
You could also build a simple arduino controlled set of relays and contactors to do it
One of recent projects required a system to control and prioritise a fan coil unit, underfloor heating and a number of radiant panels simples the controls cost £1200 to design, supply and install - works perfectly, client over the moon with the results.

Having said that unless you've got >4kWp you're probably wasting your effort, just go for a twinned immersion TS or dhw cylinder

 

[amlu]

if you have spare time then you can do it using a microcontroller (atmel, arduino, pic etc).
Add some sensors and relays and rewrite your block diagram into C language.

 

[sean_ork]

Or get a head start with the OEM - Diverting surplus PV Power, by Robin Emley | OpenEnergyMonitor

PV into a TS, cycling through 3 zones is going to need a very sizeable array to see any noticeable heat going into the UFH

 

[Worcester]

P.s. you actually need a number of extra controls and sensors than you have in your diagrams to make it work properly.
And the big question is what is the heatvsource for the ufh?

 

[sean_ork]

And the big question is what is the heatvsource for the ufh?

What's the odds for PV only ?

 

[Worcester]

What's the odds for PV only ?

Thinking electric ufh?

 

[sean_ork]

Thinking electric ufh?

Perhaps, but more along the lines of an overly optimistic expectation ........

 

[ajn9000]

P.s. you actually need a number of extra controls and sensors than you have in your diagrams to make it work properly.
And the big question is what is the heatvsource for the ufh?

4kW PV system - for the switch, haven't yet decide between Immersun, Solic, Intelligent Immersion, Wooldridge or Solar Immersion. Electric ufh: 3 zones: 1200W / 2250W / 1800W (150W/m2).

 

[jackhammerJIM]

Its been a long time since i fitted an immersun . remember in the manual an option to connect multiple outputs . Connect first output to immersion , once the immersion reaches temperature the immersun would automatically switch outputs to a secondary load . Maybe you could incorporate this feature for your ufh ?

 

[ajn9000]

Personally would always use an ImmerSun for lots of reasonsThe controls can be quite easily done depending upon which ufh room stats you have I'd use an immersun with heatmiser controls and a number of changeover contactors.If you don't understand my response, or can't research it yourself then don't attempt it and instead get it designed properly.You could also build a simple arduino controlled set of relays and contactors to do itOne of recent projects required a system to control and prioritise a fan coil unit, underfloor heating and a number of radiant panels simples the controls cost £1200 to design, supply and install - works perfectly, client over the moon with the results.Having said that unless you've got >4kWp you're probably wasting your effort, just go for a twinned immersion TS or dhw cylinder

thanks Worcester - would you be happy to share schematic for that job?

 

[Worcester]

thanks Worcester - would you be happy to share schematic for that job?

There is a limit to what we give away

Whats the heat source for the ufh?
if electric, what's the power rating in each of the rooms ?