PV immersion heater proportional control

[brian wright22]

Thanks Yorkshiremike. Retro fit its quite clear 20% vat then.

 

[Gavin A]

Thanks Yorkshiremike. Retro fit its quite clear 20% vat then.

top line - hot water controls.

it's 20% for the equipment only, 5% if professionally installed.

 

[sly_dog_jonah]

My understanding is the same as Gavin A's, 5% if it's installed professionally as it qualifies as a hot water controller.

pwboston, thanks for the your comment about amount of E7 you use. A couple of questions if you don't mind: How big is your tank? What temperature do you heat it to?

 

[yorkshiremike]

Thanks Gavin, I hadn't considered the heating controls paragraph, I guess the Immersun is an 'electronic timer'. On the HMRC site paragraph 2.6 is:

[h=2]2.6 Controls for central heating and hot water systems [/h]Central heating and hot water system controls include manual or electronic timers, thermostats, mechanical or electronic valves, including thermostatic radiator valves.

 

[sly_dog_jonah]

Thanks Gavin, I hadn't considered the heating controls paragraph, I guess the Immersun is an 'electronic timer'. On the HMRC site paragraph 2.6 is:

2.6 Controls for central heating and hot water systems

Central heating and hot water system controls include manual or electronic timers, thermostats, mechanical or electronic valves, including thermostatic radiator valves.

The Immersun is much more than an electronic timer, although that is one of its many functions. It's primary use-case is as a dynamic load controller, optimising diversion of exported power to a local load (usually an immersion) to maximise benefit from microgeneration while remaining grid-independent. Given the finite capacity of any heat storage, the device can't eliminate export, but it can certainly reduce a household's carbon footprint by reducing gas consumption (or electric heating).

On that basis it should certainly qualify for the 5% VAT.

 

[MicraShed]

Finally got my act together (and finished my IV antibiotics!) and ordered my ImmerSun install.

Bit of a shame its going to be the back end of the month before Im free to sort out the install, so Im heading into the wrong bit of the year - but Im still sure I'll see some benefit even now - and of course there is next summer to look forward to!

 

[pwboston]

My understanding is the same as Gavin A's, 5% if it's installed professionally as it qualifies as a hot water controller.

pwboston, thanks for the your comment about amount of E7 you use. A couple of questions if you don't mind: How big is your tank? What temperature do you heat it to?

It is a 140l tank, but the temperature is 2/3rds of the dial (no temperature reading on stat) however its hot enough not to have your hand under it.

 

[brian wright22]

sly_dog_jonah
QUOTE

Re: PV immersion heater proportional control
Brian, Would be interesting to compare those figures with your Gas savings over the same period (or similar period depending on when your meters were read by you/EDF).

Yesterday sent EDF my meter readings. Today the costs came back with a full 32 days worth of using the IMMERSUN . The Gas saving is for the 32 days so far £20.35..
This late September burst of Solar power is great for the bank balance

http://www.immersun.co.uk/downloads/...ide%20v1.0.pdf Section 5.4​

Read more: http://www.electriciansforums.net/newreply.php?do=newreply&p=598333#ixzz25nh1t6mB​

 

[nowty]

I got my Immersun today, there is not much to them so I am sure these are going to come down in price significantly over time. I am putting in a preheat tank for my water but probably won’t get round to it for a while yet. However I temporarily installed it from a wall socket, connected the sensor clamp and connected a £20 2kw electric heater (non fan type) to it.

The set up is easy peasy, whole job including the set up took about 10 mins. When I installed it after work I only had about 1 hr of sunlight left and I was generating about 1kw with the house using about 300w. It dumped about 600w into the heater and I monitored the house usage and PV generation on a combined energy meter I have got.

I have to say my first impressions are very very impressed. It settled down quite quickly and my energy meter was reading practically zero import / export. I played about with the heater controls as the one I bought has two heating elements 1250w and 720w which you can independently switch on or off. I was quite amazed that it deals within seconds with varying heater loads and adjusts its output to dump the same available power to different heater ratings.

Next I turned on the kettle and the heater stopped instantly with the Immersun display saying “waiting”. Turned the kettle off and the power returned to the heater again within seconds. Need to wait tomorrow to see how it copes with 3kw+ excess generation.

 

[regen]

Hi There,

I have been looking at both the imersun and the sola controller but which would be best for my application?

I have a 4kw pv limited to 3.6 via inverter which reguarly runs for several hours at 3.6 when sun shines and hoping to install a 1 to 2 kw hydro system on a stream with variable flow rates giving a max input of 5.6kw. This will be all fed via 2 immersion heaters into a 300 litre thermal store. Although 5.6 is max it is unlikely to be achieved with 4.5kw being the expected max for most of the time.

Regen