Can I add a small electric boiler in parallel with my central heating?

[gmartine]

It will increase in Winter and probably quite dramatically. Some statistics suggest to around a 1/5 of max output so that may be 10 hours to heat the the HW in your current configurtion on it's worst day. The trouble is when you want the supplemental heating on most is when your array will least be able to provide it.

 

[Knappers]

You use hot water all year round and pos more in summer. I really don't understand why this is even a question or why people are so obsessed with storing electric in expensive (high loss) batteries.
Use PV to heat domestic hot water.
After that if you've got a surplus that your not using then look at other options like a battery or Thermal store...?
At the very least you'll need a much smaller battery!
I find it so obvious that anything else is annoying.

Am I missing something?

 

[ShaunCorbs]

You use hot water all year round and pos more in summer. I really don't understand why this is even a question or why people are so obsessed with storing electric in expensive (high loss) batteries.
Use PV to heat domestic hot water.
After that if you've got a surplus that your not using then look at other options like a battery or Thermal store...?
At the very least you'll need a much smaller battery!
I find it so obvious that anything else is annoying.

Am I missing something?

High loss battery can you explain?

 

[Knappers]

The charging and discharging of batteries is going to be atleast 5-10% less efficient than use directly as a heat source.
Then the cost of the battery and degradation.
Don't even get me started on the environmental implications.
Just heat water with it, then heat other stuff.
When you've nothing left to heat, feed it back to the grid (or get smaller bank of battery's).
Maybe if you've got an electric car and are wanting to safeguard against pos energy supply issues, or want to go off grid - look at battery's first and work back.

 

[Knappers]

For this system when heating is required you could have an inline electric heater (like a pool heater) and just constantly have it running, providing background heating whenever the panels are producing enough to run the pump.

 

[Knappers]

OK maybe it would be better to use the heat when it's needed and store it but still - thermal store before batteries!

 

[Knappers]

Sorry, that was a bit of a rant.
(Please someone feel free to step in and put me in my place)

 

[gmartine]

You use hot water all year round and pos more in summer. I really don't understand why this is even a question or why people are so obsessed with storing electric in expensive (high loss) batteries.

Am I missing something?

Simples, as with wind energy production we can't always use all we produce nor do we always generate when we need. Electrical storage is the buffer that will allows us to move away from relying on fossil fuel use and at a domestic level that could be in the form of an EV or battery pack (like Tesla's power wall or Eddi's Libi device) which will of course have to be fully integrated.