PV with electric heating.

gooner99

I know electric heating has a bad name for being costly to run. But is there now a place for PV with storage heaters, electric rads, or electric underfloor/mat heating in certain instances like airtight A rated houses?

celtic_oz

yep but maybe with storage battery and heat pumps

https://www.youtube.com/watch?v=VEh7V9_uIqM&t=211s


http://heatpumpsireland.ie/applications/

wont be cheap though !

gooner99

Yeah expensive I'd say. Was thinking more in line of partially powering a much simpler heater or underfloor mat system with PV and using the grid to power the remainder. If the heat demand of a moddest dwelling is low then running costs along with capital should be good?

Also if we meet our climate targets then more and more of the electricity we use will be green.

You can use a proportional controller like an immersun to divert power to resistive heaters like electric underfloor. Not ideal though, unless the house is poorly designed at capturing heat & natural light in the Summer because PV output drops off a cliff in the Winter.

unkel

gooner99 wrote: »

I know electric heating has a bad name for being costly to run. But is there now a place for PV with storage heaters, electric rads, or electric underfloor/mat heating in certain instances like airtight A rated houses?

You can't heat a house with PV in Ireland in winter. And there is no feed in tariff for you to benefit of your PV in summer. Bluntly - don't go PV. Instead get an electric car and / or help heat your water with solar tubes if you are keen on renewables but don't want to completely waste your money.

quentingargan

unkel wrote: »

You can't heat a house with PV in Ireland in winter. And there is no feed in tariff for you to benefit of your PV in summer. Bluntly - don't go PV. Instead get an electric car and / or help heat your water with solar tubes if you are keen on renewables but don't want to completely waste your money.

Agree totally about using PV to heat a house. It will only work in summer, when you don't need it.

Not so sure though that heating water with solar tubes is the best option. PV has fallen to a price point where it may be more cost effective to put in, say 2.5kw of PV and a diversion unit to heat water. Some of the power from the PV will save you your retail electricity price, (some folks on Boards claim to use more than half the power produced) and the remainder will save you the 9c it costs to heat water with oil or gas.

The bonus over tubes is that there is no maintenance. Changing glycol in tubes every couple of years knocks quite a dent in the return on investment.

exaisle

quentingargan wrote: »

unkel wrote: »

You can't heat a house with PV in Ireland in winter. And there is no feed in tariff for you to benefit of your PV in summer. Bluntly - don't go PV. Instead get an electric car and / or help heat your water with solar tubes if you are keen on renewables but don't want to completely waste your money.

Changing glycol in tubes every couple of years knocks quite a dent in the return on investment.

Not all panels use glycol...some use plain water with a drain back system that empties the panel when necessary..

quentingargan

exaisle wrote: »

Not all panels use glycol...some use plain water with a drain back system that empties the panel when necessary..

Indeed. But not tubes. That can only be done with flatplates, and very few such systems have been implemented in Ireland. But you're right - it is a far better system.

listermint

exaisle wrote: »

Not all panels use glycol...some use plain water with a drain back system that empties the panel when necessary..

Still less hassle with pv installation

exaisle

quentingargan wrote: »

exaisle wrote: »

Not all panels use glycol...some use plain water with a drain back system that empties the panel when necessary..

Indeed. But not tubes. That can only be done with flatplates, and very few such systems have been implemented in Ireland. But you're right - it is a far better system.

Luckily, one has been implemented here....😊
I'm currently using the panel to preheat water before it goes to the heat pump...even a rise of a few degrees from the panel during winter is a few degrees I don't have to heat with the heat pump and during the winter if we get a sunny day the water from the panel is hot enough to bypass the heat pump completely.

exaisle

[/quote]
Still less hassle with pv installation[/quote]

For a system thats going to be in place for many years, an extra few hours is hardly material in the overall scheme of things.

Using heat to store heat is more efficient than using photons to release electrons and then regulate & sync power with boxes of electronics to make heat.

unkel

quentingargan wrote: »

Not so sure though that heating water with solar tubes is the best option. PV has fallen to a price point where it may be more cost effective to put in, say 2.5kw of PV and a diversion unit to heat water.

I wish you were right. I'd have a PV array up on my south facing roof tomorrow.

About the solar tubes - I'm the first one to admit that the pay back time isn't great and only really acceptable if you have a large system and you are a massive consumer of hot water.