Immersion Heater - PV electricity

[brianboru]

Ray you have my email address, lets coresspond via external means.

As long as the PV system has been fitted a certain way and you can put the equipment in a "box"
(to suit your location) . Not installations have the room to mount everything. The rest is easy.

Andy

Hi Andy
We've just had a PV system installed by Rayotec (commissioned on 9th June) with generation meter etc. in the porch and tails going direct to outside meter box. Like Ray I'm not an electrician but reasonably competent and very interested in assembling and installing the controls you have described in these posts. We have an indirect hot water cylinder fitted with with 3 kW immersion heaters top and bottom formerly controlled by Horstman Economy 7 timer. Would you be able to supply the bits and instructions? Thanks, Brian

 

[Millerman]

Brian, See posts 90 and 74 for contact details

 

[brianboru]

Thanks Andy. I'll be in touch.

 

[MBE Contracting]

wow, that sounds like a product that could do very well. Could you please give some more details. Kind regards Mick. MBE solar.

 

[Millerman]

Mick, please contact me via post 90 / 74

Andy

 

[echase]

Like a drill speed controller or light dimmer a phase angle controlled immersion is going to radiate some electrical interference, only worse because of the larger current and long cable between the immersion and fuse box. What sort of suppression is going to be needed to stop interference with say radios and TVs?

 

[inie meanie]

Well a drill has an arc across the com that is suppressed by a capacitor, but I am not sure that there will be any problem with this. I have been testing my circuit on 3 kw immersion heater with the triac control and have had no problem at all.

 

[pauldreed]

Like a drill speed controller or light dimmer a phase angle controlled immersion is going to radiate some electrical interference, only worse because of the larger current and long cable between the immersion and fuse box. What sort of suppression is going to be needed to stop interference with say radios and TVs?

This is an interesting article which discusses this aspect http://bit.ly/m1sLDY
I think that it's not so bad with resistive loads.

 

[Millerman]

burst firing is the way to go no problem with EMC. Talking to a company to develop a unit,,,,, more later

 

[inie meanie]

Hi Millerman. Forgive me but burst firing will pull full power for a determined number of cycles. (see Burst firing ) This will then give a draw from the grid and then the cycles shut off for another set period. This is only useful for the power control of a heater temperature not what you need for balancing a load. I have just completed my circuit that measures the two power levels ( current coils, no need to phase reference if you go on output from dist board, several cores can fit through one coil no problem, remember to only use one from each ring circuit ) compares them and provides an output via the triac. It keeps the house just exporting a small amount of power whilst dumping what else is free into any resistive heating load. I used a 741 to compare the two signals, pass this onto another 741 which adds a reference voltage ( zero point ) and adjusted the gain via pot on feedback gain to alter the slope, thus totally analogue and very cheap. No problem with EMC at all. It can only do this by working at a cycle level. Burst mode will cost you power consumption sorry.