How many PV panels to keep a thermal store topped up with no use?
edited 10 April at 2:59PM in LPG, heating oil, solid & other fuels
5 replies 102 views
Just thinking aloud.
Exploring bio-mass for a house that is often left unoccupied for a couple of weeks - sometimes even a couple of months - at a time. Biomass is usually used via a thermal store, and this has the benefit of being able to have other sources of heat added to it - solar heat panels, PVs via an immersion, solid-fuel stoves, etc.
As I understand it, biomass has the disadvantage of being a sluggish heat source, so to turn up to a cold house would likely be an unpleasant experience for a few hours? (Unless they can be turned on remotely using an App, like other boilers can? This would obviously be an auto-feed boiler.)
Anyhoo, if designing a new heating system from scratch, how well would a couple of PV panels manage to keep a thermal store nicely hot and ready to go when the house is unoccupied? Assuming, of course, an average amount of sun. There would be no consumption of that stored heat over the unoccupied periods, and thermal stores are presumably very highly insulated? So, pretty much 'anything' from an immersion heater should be useful? On arrival, this stored heat can be used to get the house's rads running right away, whilst the biomass boiler kicks in and takes over. That's the idea...
Average PV panels have around 250W output? A couple, 500W, so surely a useful amount? Over a period of, say, 2 weeks or potentially much more, there is almost bound to be some decent output, but what is the chance of it getting - or just maintaining - the TS at its normal operating temp over that period? In essence, would the output of, say, 2 panels be able to match the heat loss from the TS? The TS would likely be left in a charged state when the house is left, so the PVs would usually only need to counter heat loss.
Does anyone have an idea of this?!
If it's potentially a goer, what's the cheapest way to get a couple of panels and a ~1kW inverter setup? The immersion element would be able to control itself via its 'stat, so just shut off the power to it when demand has been met.
Thanks for any thoughts on this :-)
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