Using excess power

[tomallen]

I have just installed a 30kW 3-phase array and one of the draws from it is 4.5kW heat pump for a swimming pool. I want to wire up the heat pump so that it only draws when there is excess power. I've looked at an Immersun 2 unit, which looks as though it may do the job, but am unsure, and also wouldn't have a clue how to install it, so have a number of queries.

Is it a good idea to connect a heat pump to an Immersun unit? Max load per outlet for the Immersun is 3.2kW, but it looks like you could do so through the Multifunction relay terminal, that I presume you could connect to a relay that operates the pump. There are time delays and minimum thresholds built into the Immersun settings so that it wouldn't flick on and off every time the sun came out, that could damage the heat pump, I presume. Also, I understand heat pumps create a surge when they first come on. Can an Immersun handle that?

How do you connect it remotely? My supply meter is 60m from the pool. I don't think even the wireless unit will reach that far. I have a CAT5e connection between supply meter and pool shed - can the relay signal travel down that? Perhaps I should connect the sensor through the CAT5e?

Is an Immersun the best option at all? The heat pump is just about the only item connected to that phase, so all I really need is a switch that will turn on when it's sunny enough. But the only light-sensitive switches I can find are dusk till dawn ones that switch on when it's dark (the reverse of what I need) and none would be suitable for the power draw and time delay, etc, needed for a heat pump.

 

[jason121]

Have you looked at the Elios. Andy from Sibert will help you. He posts on here

 

[tomallen]

Thanks for this Jason

It looks like the Elios can only handle resistive loads up to 3kW, so I'm not sure it would do 4.5kW heat pump. There are also settings for the Immersun that allow you to make sure it doesn't kick in until a minimum exportable surplus is reached. Having said that, There's a lot in the Immersun I don't need (like the ability to add a number of immersion heaters) - it's just the relay I want, I think. So I don't know if there's a better system out there.

 

[jason121]

Speak to Andy he will tell more about the functions of the Elios. Can be used on 3 phase

 

[Gavin A]

Thanks for this Jason

It looks like the Elios can only handle resistive loads up to 3kW, so I'm not sure it would do 4.5kW heat pump. There are also settings for the Immersun that allow you to make sure it doesn't kick in until a minimum exportable surplus is reached. Having said that, There's a lot in the Immersun I don't need (like the ability to add a number of immersion heaters) - it's just the relay I want, I think. So I don't know if there's a better system out there.

look at the elios unit not the power reducer, it has a 10 amp relay, but you just need to switch a contactor really. There are wireless contactors available as well, not sure about 60m range though.

 

[SibertSolar]

Elios4You monitoring platform, either the 1ph or 3ph unit, has an on board relay that is rated at 10A so an external relay/contactor might have to be used. The APP-based interface/GUI allows you to program the relay to switch at different upper/lower thresholds, to provide hysteresis/avoid hunting. You can also program the relay to switch via the APP's 24hr/7day time clock.

The 1ph unit will monitor generation/consumption/import/export on one phase only, the 3ph unit (Elios4You PRO) will aggregate the generation/consumption/import/export of all 3 phases.

 

[Worcester]

The ImmerSUN II has similar functionality, though only through specialist installers, not from the mainstream wholesalers.

 

[jason121]

Yep that's right EBAY

 

[Worcester]

Is it a good idea to connect a heat pump to an Immersun unit? Max load per outlet for the Immersun is 3.2kW, but it looks like you could do so through the Multifunction relay terminal, that I presume you could connect to a relay that operates the pump. There are time delays and minimum thresholds built into the Immersun settings so that it wouldn't flick on and off every time the sun came out, that could damage the heat pump, I presume. Also, I understand heat pumps create a surge when they first come on. Can an Immersun handle that?

Yes, run it through a contactor, - you'll probably have a type C breaker on your ASHP anyway - see my comment at the end re cycling on and off.

How do you connect it remotely? My supply meter is 60m from the pool. I don't think even the wireless unit will reach that far. I have a CAT5e connection between supply meter and pool shed - can the relay signal travel down that? Perhaps I should connect the sensor through the CAT5e?

Switch the ASHP via a contactor

Is an Immersun the best option at all? The heat pump is just about the only item connected to that phase, so all I really need is a switch that will turn on when it's sunny enough. But the only light-sensitive switches I can find are dusk till dawn ones that switch on when it's dark (the reverse of what I need) and none would be suitable for the power draw and time delay, etc, needed for a heat pump

.

Heat Pumps don't like cycling, so the ImmerSUN 11 can be configured with minimum on and minimum off times specifically for installations such as this. Note the reason for my comment above is that a number of the wholesalers still have stocks of the early ImmerSUN 11's that don't have this specific functionality - it's a firmware update applied in the last few weeks.

Is it the best ? That's up for debate, the elios units are also good units, and Andy is a good source of knowledge.

 

[Meggerman]

You don't need to switch the whole unit through contactor. Power the ASHP directly and take the control live (switched live if you prefer) through the integrated relay.

 

[Earthstore]

Just a thought, but would adding a large thermal store into this system be beneficial?
I am aware that some calculations would need to be done, but with 30KWP of PV ROI could be quite short.

 

[tomallen]

Is it the best ? That's up for debate, the elios units are also good units, and Andy is a good source of knowledge.

Thanks for this. I've looked at the Elios - it has all sorts of whizzy bits that let you monitor the system, but I've already got a load of efergy meters doing that.

Many thanks for your advice - I've gone ahead and bought an Immersun - I think it's the right one, but will check as you suggest.

It may be an idea to add a thermal store, too, as Earthstore suggests.

 

[solarfred]

There is a new upgraded EMMA coming out soon which will be a lot cheaper than existing with better functionality so it may come back into the mainstream.