Anyone got one?
I've just deleted what i'd originally typed because my plan was to run it from some sort of solar setup but I had no idea they used so much power.
I fancied a sort of partially off-grid experience but it seems like you'd still be reliant on electricity and potentially forking out more money to run it with massively higher installation costs.
So, horses and logs then....
My understanding is that you get more energy back than you put in - possibly by a factor of 2-3x.
However my opinion is possibly clouded by the number of sharks - sorry "government approved contractors" that you have to use to get any grant money. We're back to solar panels etc.
I'm not saying I don't trust "approved" contractors, even if I could do the job for 1/10th the price. What I am saying is every visitor DW has from the LA or NHS has immediately noticed that our level access cannot have been supplied by them as it's "too good".
....my heat exchanger fan and pump takes 4kVA and immersion heaters 6kW to start running an hour before any heat is distributed, from a cold start.
ArtStudent?
Steam engine and burn your pets
Yes. The installer could have done a better job but it works fine.
If you're running off-grid, you need a substantial battery/inverter to handle the ASHP starting current. Here's someone developing such a system, who says you need about 30A (7.5kW), which means two 4kW inverters:
Theo
They'll snitch on you to the planners or BCO if you're not careful, because if it is DIY then you will have done a small army of overpaid LA and NHS pen-pushers out of some 'work'.
Wood and straw are your cheapest fuels.
I looked at HeatPumps for my house - cost is very high, and pretty significant power consumption. I have an interesting report from a University Professor on Heat Pumps, the conclusion was air-air heat pumps are simply not efficient enough for a domestic environment.
Here's my whole-house meter readings since the ASHP was installed:
December: 834.5kWh January: 967.5kWh February: 805.9kWh March: 682.3kWh
'baseload' prior to the ASHP was about 10-15kWh per day, let's call that
400kWh per month (electric cooking, oil heating).So that's been 1700kWh for heating and hot water for most of a winter. The house is pretty average, EPC borderline D/E (the EPC was out of date and it was reassessed as a D despite nothing having changed since it was an E).
On a cold winter's day the house takes about 35kWh, on a mild winter's day it's more like 15kWh.
We'll see how that plays out over the rest of the year, but to note heating oil has been about £1/litre recently (dropping down slightly). We would use about 1200 litres a year which is about 12000kWh. We used essentially no oil in the 6 summer months, so almost all that 1200 litres was used in winter.
Even with the increased cost of electricity I'm pretty happy with that.
Theo
And what happened to all that baseload that didn't end up as heat for the house, pray?
Small house then.
Still seems quite a lot though for lights, cooking and heating pumps and controllers. Cooker hobs and ovens only need a big burst initially but then effectively idle.
EPC means nothing. It's the construction, location, orientation and insulation that matters.
But does your oil boiler do the hot water all year ?
How much are you paying per unit from April though
Well, actually, some major appliances don't emit their heat into the house: dishwasher, washing machine, electric shower put a good chunk of their heat into the drains. Some cooking also does (boiling water that later goes down the sink), some doesn't (frying, oven). For others, freezer and tumble dryer, they're not in the house so their heat does not contribute to reducing the heating bills.
Apart from the electric shower (now fed off the tank, saving 1kWh/day from 'baseload') all of these were the same before and after. Hence the only fair comparison is to exclude them from the difference before and after.
125m2, so about average.Theo
Then there are the computers... The variability is often dishwasher / washing machine / tumble dryer usage.
Indeed. But point being it's not anything special.
Only for baths. Previously there was an electric shower and the kettle was used for washing up. The electric shower took ~1kWh/day.
~30p/unit like everyone else.
Theo
Ok. Can you trap any of the heat generated by the compressors themselves ?, like by putting it against a shed wall so that some of the heat slightly warms the shed (or greenhouse) ?
I haven't taken it apart, but it may be the compressors are cooled in the intake airflow. That means the heat contributes to what's being 'pumped' into the refrigerant - it slightly prewarms the ambient air.
However, that would reduce efficiency in cooling mode, so it's not a no brainer to make that tradeoff. It may be there's some kind of liquid coolant that can be directed either way depend on mode.
You wouldn't put the unit up against a wall because that would block the intake airflow and reduce the efficiency. There's a 30cm gap behind it to permit enough intake volume.
Theo
That is bullshit in some environments.
Interesting take
Yes
It assumes that grid has got the capacity. Where he lives the grid has got ample capacity to support large AC use in the summer months and therefore the same kind of use is possible for ASHP in winter. In the UK there is very little domestic AC.
I have just installed some A/C which of course is actually an Air/Air heat pump. Looking at rough figures it still looks more expensive than my gas boiler, even with a COP of 5 but perhaps with targetting heating it will be better.
I also feel conventional radiators which rely on convention can't be that great at heating a whole room...
Dave
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