Posted by: @morgan

Just read this on the BBC News website and would be interested to read comments.  I scuba dive and cringe at news reports or documentaries that refer to things such as oxygen tanks, flippers, the bends, goggles etc.  

One part I’ve extracted is:- To be "ultra-efficient" she decided to install a whole new heating system. Solar panels were fitted to the house, along with an air source heat pump. The heat pump and panels work together with a passive heating system - a mesh of pipes encased in concrete, that stores heat in summer and slowly releases it over the winter………..really?

https://www.bbc.co.uk/news/business-61068688

 

 

Sounds like the best thing since sliced bread, put me down for two. 😎 

Katherine Latham is obviously really on the ball.

Posted by: @derek-m

 

Sounds like the best thing since sliced bread, put me down for two. 😎 

😂😂😂

@morgan

Joking apart, I read some time ago about schools in America that have ground source systems, that provide AC in the Summer and heating in the Winter. They basically extract energy from the building internals during the Summer period and deposit it in the ground, and then extract this energy during the Winter. Since it is a ground source system it will be more efficient than air source, though I am not certain if the stored energy would last out the Winter.

I feel to do something similar in the UK, though not impossible, would have limited benefit. First you would need a ground source system that can extract energy from the outside air, unless you enjoy arctic conditions indoors, and deposit this energy in the specified concrete block, unless the article was actually referring to an indoor concrete slab. If the concrete block is indeed outside, this is where many more what-ifs come into play. Of course whilst it is deposit energy in the concrete block it would not be able to perform any form of indoor heating. You may need a second heat pump for this purpose.

Assuming that the Winter heating period lasts 90 days, and the average daily heat demand is 100 kWh's, this would give a total heat demand of 9000 kWh's. Let's be generous and say that the average COP of the GSHP is 4, so during the 90 day period it would require an electrical energy supply of 2250 kWh and a heat energy supply (from the concrete block) of 6750 kWh's.

If this 6750 kWh's of energy is to be stored in the concrete block, by raising its temperature from say 10C to 50C, it is now possible to calculate the size of block required. To heat 1 kg of concrete by 1C takes 3400 Joules of energy, so to raise the temperature by 40C would require 136000 J.

1 kWh is 3600000 J, therefore 6750 kWh is 24300000000 J, so to store this amount of energy would require a concrete block weighing approximately 178.7 Tonnes or 74.5 M3 in size. This of course assumes that there is no loss of energy in the process.

To put the energy into the store during the remaining 275 days of the year, again assuming an average COP of 4, since it is now operating as an ASHP, would require an average electrical supply of approximately 8.2 kWh.

So quite an easy task after-all.

No surprise to me to see a high temp pictured sadly. There's obviously going to be a big push for these regarding the retrofit market but running costs are higher than for a standard pump, and you don't see that in the headlines.

I've seen that a few of these have been gifted to some influencers and the set up with the hydraulic module and all lagged and correct sized pipework etc. etc. in what looks to be a garage or pumproom is probably going to be very far removed from what the average person will end up with if my experience is anything to go by!