Do immersun type devices work

[adamgp]

Plenty of cheap offers on Google to take advantage of regardless of whether you're a trade customer or not.
Shouldn't take more than an hour to wire from the distribution board to an immersion heater. It only needs about 135 watts of excess power before switching I believe and trickling all excess to the heater!

 

[nicksgonesurfin]

I think this brings an interesting challenge to behavior, 100yrs ago we would have bathed (if we actually did bathe) With the fire heated water, possibly after cooking and eating using the fire. mainly in the evening. Going to bed clean.

Perhaps we have to bathe in the evening?!

another idea is to insulate your tank further or design so the losses over night are minimised and all the PV powered heat is maximised and ensure when the last person has had a shower the HW is turned off so no heating except the solar can go into your system.

seems a lot of hassle i know but its a little like stoking the fire to a roaring flame then going off to work. we wouldnt do that. Because we are disconnected from our energy we don't think about our boilers working when we are not there. (some people do, Timers etc!)

 

[adamgp]

Absolutely, and set your gas boiler to kick in the evening after the sun has set or is setting to make up the difference.. at least this is what I do to maximise the PV energy usage.

 

[bommels]

For more than a year I have been running an early DIY immersion controller, with energy logging capability. Attached is a bar graph of the generation in kWh for April 2013 (2.88kWp array).
The logging allows tracking of where the energy goes: yellow indicates export to grid, red means it has been diverted to the immersion heater, and green marks the PV energy that has been used elsewhere in the household. The system has proven to be so effective that we rely on it entirely for domestic hot water in summer. And, as you can see from the plots, there is still room for improvement, as 42% of our solar PV production was pumped into the grid.

Do immersion controllers work? Certainly they do!

 

[BruceB]

Coincidentally, I had an email today from one of my customers I worked with in the early months of this year putting right a solar pv, solar thermal and ashp installation put in by others. He is full of praise for the immersun. He has about 5kW of PV and a 300 litre Gledhill thermal store in the loft.

"...The Immersun unit has diverted 428 Kwh thus far and is the biggest positive of the project. The only slightly off-putting thing is the noise of a monstrous kettle going off above your head in the bedroom. On a sunny day there are 3Kwh going into the immersion, and you do know it. It becomes the sound of money being saved, and you come to love it........."

 

[BruceB]

I also installed a bank of three thermometers showing the top, middle and bottom temperatures of the thermal store. £10 each from Maplins mounted in his sitting room. Just extended the sensor cables with cat5e. Cheap, cherful and effective. 3-in-1 Digital Probe Clock Thermometer : Thermometers & Hygrometers : Maplin Electronics

".......The three temp gauges in the tv room are the most cost effective part of the deal; we now know exactly what we are dealing with and how effective the wood burner is at a quick burst of heat in the evening; superb."

 

[danesol]

For more than a year I have been running an early DIY immersion controller, with energy logging capability. Attached is a bar graph of the generation in kWh for April 2013 (2.88kWp array).
The logging allows tracking of where the energy goes: yellow indicates export to grid, red means it has been diverted to the immersion heater, and green marks the PV energy that has been used elsewhere in the household. The system has proven to be so effective that we rely on it entirely for domestic hot water in summer. And, as you can see from the plots, there is still room for improvement, as 42% of our solar PV production was pumped into the grid.

Do immersion controllers work? Certainly they do!

View attachment 19012

How many CT sensors have you got fitted to get that level of info and what make are they - do you have a central monitor too ??

 

[bommels]

Hi Danesol,
My setup uses 2 clamps. One clamp sits around the tail at the consumption meter, measuring net import/export, the other clamp sits around the tails leading to the PV system.
Earlier, I have verified that the actual power going into the immersion heater corresponds to what the system thinks is going in there, so I do not have to use a clamp for that.

The clamps were recuperated from the scrap heap and have custom resistors fitted to limit the amplitude/range. Presumably the usual clamps would work just as well. I have not been chasing sub-1% accuracy I must admit.

 

[apj]

I'm considering PV, with flat roof garage could get 6kw system.
heating system is oil, so in addition to immersion i was considering some additional wall mounted rads with heating element direct from PV, can the immersun divert to more than one outlet or would multiple units be needed?
BruceB, graph is a very good idea, a couple of very low generation days - were these much more frequent over winter??

 

[danesol]

I'm considering PV, with flat roof garage could get 6kw system.
heating system is oil, so in addition to immersion i was considering some additional wall mounted rads with heating element direct from PV, can the immersun divert to more than one outlet or would multiple units be needed?
BruceB, graph is a very good idea, a couple of very low generation days - were these much more frequent over winter??

Would it even be worth it going over the domestic threshold of 4KW, considering for a moment rates change commencing Aug 2013 and the reduction in tariff going over 4kw ??

The immersion question is possibly secondary to this ?

All I would say is do the numbers very carefully - I assume you will stay in the building for the next 20yrs too !!!

 

[apj]

Would it even be worth it going over the domestic threshold of 4KW, considering for a moment rates change commencing Aug 2013 and the reduction in tariff going over 4kw ??

The immersion question is possibly secondary to this ?

All I would say is do the numbers very carefully - I assume you will stay in the building for the next 20yrs too !!!

Well the reduction over 4kw is not so much now, so will see. I've already got plenty of numbers to crunch just trying to compare the quotes, there's just a ridiculous difference between some of the quotes with nothing seeming to be true like for like, with everyone either claiming their panels are 'so much better than others on the market' or that there 'really isn't much difference between them all'!!