UK - Solar PV - Immersion heater controllers

[sunandwindy]

I've come across a product that controls loads such as immersion heaters or under floor heating to use excess power that would normally be sent out to the national grid (so no financial gain to the PV owner - its all to do with feed in tariff payments).

One company I have found is ImmerSUN (approx £500 plus fitting). Apparently they insist they have their agent fit the unit, but as a qualified sparky who used to teach apprentice sparkies at a local technical collage, that definitely not a route I wish to follow.

Another company is Earthwise who offer SOLIC 200. I think they're half the price of the above, but still checking.

Does anyone know of any other companies/products please?

[DamonHD]

Look at YouGen that did a list, I think, and the greenbuildingforum.co.uk which has discussed at length.

HOWEVER, I think it is a criminal waste of electricity (especially from solar PV) to use in resistance heating rather than exporting it to the grid where you help cut fossil fuel generation at times when demand is definitely there (which is why the FiT exists) or using a heat-pump to get 2 or 3 (or more) kWh of heat for each kWh of electricity.

Rgds

Damon

[gww]

Damon
I hope I am not wrong or totally hijacking this tread but to your point that you raised:
Do heat pumps have motors that would be hurt by getting pulse type current or low current due to lack of voltage/amps?

The reason I ask:
I am not going to get a grid tie agreement and so intend to use opertunity loading.  If the above question doesn't work, due to start up load or bad for motors,  You couldn't use an ssr as chris does in his thread on using the clasic cc to heat water.

Some control systems may only work with pure resistance load?

I don't know about heat pumps and that is why I broke into this thread.

Thanks
gww

[DamonHD]

gww: If the PV is grid-tied for FiT (feed-in-tariff) then that simply won't be an issue, as the heat-pump will be on mains all the time and all that will change is whether power is flowing in or out of the house at the time that it is running.

Otherwise it will depend entirely on the equipment concerned.

Rgds

Damon

[hydrosun]

I've got two heat pumps on an off grid system. The first one I installed I used the relay off the Outback controller to turn on and off a power relay to power the heat pump. The heat pump is designed to restart after a power outage, so it worked fine. The second heat pump is an inverter style heat pump. I didn't like the power going off and on and it needing to reset itself before starting up again. So I figured out a way to put a resistor in parallel with it's temperature sensing thermistor. When the relay puts the resistor into the circuit the total resistance decreases and the heat pump controller senses a much lower temperature and tures on the heat. When the voltage goes down the relay opens and the resistor is not part of the circuit and the heat pump senses a higher temp and shuts down the heat, but the heat pump controller still has power. In the inverter heat pump the se and nsor is in the remote control and I used an led/photo sensor and resistor to isolate it from the power control. The older heat pump I just ran two wires from the outback controller and the resistor in series with the thermistor inside the indoor blower unit. So when the relay is on it bypasses the resistor. It all depends on what controller you use and whether you are reversing the on state with another relay. I think I used a 1K ohm resistor to change 4 degrees on a thermistor at 5k ohm. On the first one I played with a reostat to get the right resistance. The thermistor is located on the coils on the fins of the interior coils and I just cut one of the wires going to it and inserted the resistor. So a very small modification to get the heat pump to go on at higher voltages and off when the voltage goes lower.
Chris

[gww]

Chris and damon
thanks for the reply.  If I want to know more I will start a new thread or maby ask more on Chris O's thread.  I have a outback mx60 and fm80. 
Hyjack over now.
gww

Ps Chris,  I was talking more about using an ssr to feed what ever pv power that was being wasted while the batteries were getting charged.

[mab]

I've come across a product that controls loads such as immersion heaters or under floor heating to use excess power that would normally be sent out to the national grid (so no financial gain to the PV owner - its all to do with feed in tariff payments).

One company I have found is ImmerSUN (approx £500 plus fitting). Apparently they insist they have their agent fit the unit, but as a qualified sparky who used to teach apprentice sparkies at a local technical collage, that definitely not a route I wish to follow.

Another company is Earthwise who offer SOLIC 200. I think they're half the price of the above, but still checking.

Does anyone know of any other companies/products please?

Have you talked to immersun themselves?

I've fitted two of these for customers (sorry Damon) and I'm just a regular sparky; the customers bought the immersuns direct and paid me to fit them & certify. That was several months ago, though, when they first came out so maybe they've had issues. If it were me I'd give 'em a bell and see if you could talk them into it.

[sunandwindy]

I've come across a product that controls loads such as immersion heaters or under floor heating to use excess power that would normally be sent out to the national grid (so no financial gain to the PV owner - its all to do with feed in tariff payments).

One company I have found is ImmerSUN (approx £500 plus fitting). Apparently they insist they have their agent fit the unit, but as a qualified sparky who used to teach apprentice sparkies at a local technical collage, that definitely not a route I wish to follow.

Another company is Earthwise who offer SOLIC 200. I think they're half the price of the above, but still checking.

Does anyone know of any other companies/products please?

Have you talked to immersun themselves?

I've fitted two of these for customers (sorry Damon) and I'm just a regular sparky; the customers bought the immersuns direct and paid me to fit them & certify. That was several months ago, though, when they first came out so maybe they've had issues. If it were me I'd give 'em a bell and see if you could talk them into it.

I've not spoken/contacted ImmerSUN as it appears they want to do sales via their agents who all want to install. I've messaged back those who came back with prices (usually around £600) that I wanted supply only, but none have responded! ImmerSUN do clearly show on their website what their unit will do, but there does seem to be others who are half the ImmerSUN price, but wondering if others had hands on experience of other devices?