Posted by: @jamespa

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If you want to store in a tank for later space heating you would need a much bigger tank and different pipework.  Its possible in principle but the scale of storage needed makes it difficult or impossible in practice.

Yes, you need something like this:

This kind of set-up is very common in places that use wood boilers here in Finland. The tank you see in the picture (the white/red cylinder) has a capacity of 3000L. The picture was taken while I was installing the wood gasification boiler (the red thing in the middle) and heat pump at my house. i can store heat for several days for both heating the house and hot water.

I love it.

In a UK context, the space that the cylinder sits in is the size of a bedroom, which in the South of England affects the house price by north of £100K (for some reason we sell houses principally by number of bedrooms not floor area, which, together with sky high land prices, incentivises tiny rooms in small houses).

Also even if you can get 55C of useful temperature drop out of it (heat to 95, cool to 30) it stores only 190kWh, enough for an not atypical 8kW house for a day.  (We didn't, until relatively recently, bother to insulate our houses, because we have a mild climate and very cheap gas/coal - our gas is still very cheap).

Posted by: @jamespa

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Also even if you can get 55C of useful temperature drop out of it (heat to 95, cool to 30) it stores only 190kWh, enough for an not atypical 8kW house for a day.  (We didn't, until relatively recently, bother to insulate our houses, because we have a mild climate and very cheap gas/coal - our gas is still very cheap).

For reference, my house heat loss only gets to 8kW with an inside temperature of 22C when it's -40C outside...

@jamiejones85mespa your comments are spot on with my thoughts the past few years. As energy prices soared, id decided to invest in Solar and a Heat Pump.i decided to insulate everywhere I could, floors and new walls are 150mm to code. The extension surrounds the house and Ive noticed heat is trapped in side the old part of the house. I insulated the new extension roof with 150mm and now adding extra insulated plaster boarding to the exterior walls in the old rooms in the house. New ceilings downstairs are being insulated with 100mm rockwool to stop heat migrating upstairs and added sound insulation to walls with the Heat Pump close to it.ive been tweaking the system settings for a year and have gradually improved the COP from 3 something to high 4’s and this week I achieved my first 5 

dropping the cold setpoint for FT from 50 to 45 is likely the cause of the improvement.