Switching on Immersion heater.

This thread titled "Switching on Immersion heater." is posted in the under the Solar PV Forum | Solar Panels Forum on Electricians Forums.

There is actually now an out of the box solution that will work on (almost) any installation: greenologic.co.uk

View attachment 10224

Let me know what you think ...

We turn off our oil boiler May - September, so gotta use our own 10kWp system somehow :)
 
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I like the EMMA unit ......... I like the Parsons Switch.......... I like the Greenlogic...... but which is best......?????? FIGHT!!!!!!
 
Greenlogic a fraction of the price of the EMMA...

Greenlogic and EMMA make sure you ONLY switch on the immersion when you have EXCESS power (i.e. were about to export)

Parsons, is simplest, however if you don't manually interupt it on a median day, and you have the washing machine on, looks like you'd end up paying for the heating of the hot water. - Our house runs a base load close to 1.5kW so the Parsons would mean that we'd be paying full whack to heat it (it assumes a base load of only 500W)

I'll give the guy at Parson's a call as he's only up the road and I've got a customer with a 50kWp system that's not being paid for export (meter costs too high) so we want to use all we can when we can without importing.
 
We have to install EMMA's in a 10kw PV/Biomass/ST/Buffer installation but they are unavailable right now.
And then we have to find a way of controlling 25kw going into a heat pump or Electric element to heat a swimming pool from PV only. One of these units will be the one but I am researching which will be best. If anyone has done a pool system using ASHP I am looking for advice. The cost and power demands are quite staggering for a large HP. The EMMA is the most sophisticated and has great technical backup but cost is an issue.
 
Worcester said:
There is actually now an out of the box solution that will work on (almost) any installation: greenologic.co.uk

Let me know what you think
Click to expand...

I think if you just want to control the immersion heater it looks over-complicated and expensive (though may be not as expensive as the EMMA, but that wouldn't be difficult).

The attachment talks of controlling the immersion heater via a "relay". If this is only on/off then it will not provide the graduated control necessary to make optimal use of the solar generation. In particular if you wait for there to be 3kW excess power you might be waiting all winter.

Looking on their web site for further details I found (after fixing the broken link) this pdf http://greenologic.co.uk/SharedFiles/Download.aspx?pageid=28&mid=141&fileid=5.

Some of its claims are alarmist and difficult to believe, can they substantiate them? Specifically:

<Dishwashers left on at the end of their cycle consume 70 per cent of the power used when they are running.

Washing machines use just under 20 per cent of their normal electricity requirement on standby.Tumble-dryers can use 38 per cent of power while waiting at the end of a cycle​
​
​
​
>

I have owned several different dishwashers, washing machines and dryers and apart from the few watts required to drive the display none of them consume any power either at the end of the cycle or on standby. Where do they think the power goes?

I assume that since you have posted on this topic elsewhere that Worcester Renewables are resellers of this system, it would be good to have an indicative price for the basic immersion-heater only system (perhaps on a supply-only basis).

P.S. I hope they have got a licence to use all the borrowed artwork which Adobe Reader helpfully tells you the source of<g>.​
 
Nope we are not resellers to the trade of the system, like eveyone else we are looking for the best solution to managing the use of generated electricity to minimise or eliminate export.

Cost are retail £600, trade get usual discounts.

EMMA's are expensive and there has got to be a better solution.

One of my concerns is the 'cycling' of these units - excess power, switch something on, no excess power (becasue your using it :) ) switch it off.

As such a system needs to be able monitor and control multiple power consumers and also ideally be able to feed a variable amount of power, so it needs to monitor generation, unmanaged consumption and managed consumption.
 
If you wanted to dump any excess power to a water heater it is very simple, back of an enevlop desgin even. Base it on a solid state relay with a couple of current clamps, tune the feedback circuit and it will cost a few pence per hour of additontal power.
 
Worcester said:
... a system needs to be able monitor and control multiple power consumers and also ideally be able to feed a variable amount of power, so it needs to monitor generation, unmanaged consumption and managed consumption.
Click to expand...
Something like this perhaps ;-) (The washing machine's on so nothing being fed to immersion in this example)
normal_IMAG0219.jpg


Here it is feeding nearly 1Kw to the immersion (which is a 3Kw element), now the household consumption has dropped.

normal_IMAG0220.jpg
 
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Why? If you're variably feeding it then it doesn't make a difference what size the immersion is, except for the fact you're artificially capping the max power you can dump into a 1Kw element...
 
Have searched a lot of suppliers - but none of them do 1 kW or are much expensive (over £80!!) or have to custom build them .. atleast 100 pc's . Please let me know if you know any cheaper ones .

Stuart - Yes, I have see than. Unfortunately, I'm not an electronics guy .. and I may have to struggle with weeks and still the cost than £100 with a contact relay and accessories to make it safe.

Really confused
 

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