Hi,
Electric Vehicle batteries are
very dangerous, with complex safety features, but it appears that the basic Leaf has a 24 kWh battery (probably now quite degraded) which can be replaced by their 40 kWh unit, at a cost approaching $10k. Also, the Leaf is said to be "outdated", but if that avoids a single touchscreen and deep menu structure for the
driver to control, then I 'd be very happy.
And it does have the (relatively unusual) capability to feed power into an
external load such as your house, for example overnight when there is no sun. A Domestic PV battery pack such as the Tesla Powerwall costs around $10k and stores only 13.5 kWh.
Heat Pumps and Air Conditioners use basically the same mechanism, so a single unit can actually perform both functions, but usually in the form of "air in - air out". That's needs complex/expensive ducting for heating/cooling a house, particularly retro-fitted, but is very simple for a car! So I'm astounded that for many EV's (where energy availability is obviously critical) a Heat Pump heating combined with the Air Conditioning system is "Optional" or even Not Available.
I don't know about a "bladder" but in UK, Underfloor Heating is becoming more common, in the form of warm water pipes (preferably) or electric heating cables (not). Particularly in association with a Heat Pump which gives relatively lower temperature water (compared with a boiler) and thus needs a larger area of radiator/convection/conduction surfaces than our normal (wall-mounted) hot water radiators. I have my reservations about a floor's "controllability", i.e. thermal inertia preventing the use of heating only "when required", but at least "Hot Air Rises" (e.g. from the floor). For a cooling system, might not the bladder/pipes need to be on/at the ceiling/roof ?
The problem in the UK is that we may use almost 90% of our home energy during the (4 - 6) "Winter" months (e.g. 15 MWh from gas heating) with around 3 MWh electricity consumed fairly constantly during the year (little/no air conditioning required). But UK-located PV panels generate only around 10% of their yearly output (say 300 - 500 kWh for a house) in the three winter months. Thus the "solution" appears to be wind generation (which is totally unrealistic for the vast majority of people/homes to do locally) combined with Heat Pumps (requiring "only" a doubling of the electricity supply infrastructure). Then an enormous amount of
electricity storage for the days or a week when the wind doesn't blow. So the Holy Grail might be thermal storage (under buildings) from summer until winter, but I suspect that would be a major constructional addition even for a "new build" property.
We are seriously considering replacing our Gas boiler with a Heat Pump, but need to "improve" the house insulation (or at least its "Energy Performance Certificate"
) to qualify for the
Government Grant, which is (IMHO) excessively generous (> 50% of cost) but ludicrously under-funded (~ 1% of the housing stock). But I'd better not get onto the (enormous) deficiencies of the EPC.
Cheers, Alan.
