any issue with 500litre UVC with 8kW ASHP

[volcane]

Hi all,

 

Literally crawling to the finish line but still hitting landmines.

 

Latest is the issue of the size of the UVC. I had requested a 500litre to cater for 5 showers 1 bath house,  kids with additional needs, guests if they ever return and my often dirty job requiring a good evening scrub!

 

Daikin is the chosen ASHP due to availability and local knowledge but suppliers differ wildly in what they say will work and what won't. I now have 3 alternative views, when all presented with the same data.

But none are willing to specify a 500 litre UVC tank saying 300 is the max on offer, but one offers a 500litre Daikin thermal store. The explanations defy the laws of physics but I require the system to be commissioned correctly for the warranty to be valid.

Surely if a 500litre thermal store is acceptable a 500lite UVC should also work.

 

All opinions valued

 

Thanks

 

[PeterW]

Nope - a 500 litre UVC will take a bit longer to get to to 50°C with an 8kW ASHP flat out, but it’s the difference between 2.35 hours and 1.45 hours to get from 18-50°C. An extra hour, CoP of 3 so overnight on E7 that’s an extra 25p or so to heat the tank for peace of mind ..? 
 

A 500 will come with 2 immersions too, and you can spec a pair of thermostat pockets so you only heat the top if you want to when the house isn’t full. 
 

Other option is a pair of 250 litre UVCs side by side and only heat the secondary when you need the capacity. 
 

Either way it’s your spec and your choice. It will work, assuming you have doors wide enough to get a 500 litre UVC through, but I don’t know why suppliers are saying no. 
 

 

[nod]

?

[ProDave]

1 hour ago, volcane said:

 but one offers a 500litre Daikin thermal store. The explanations defy the laws of physics but I require the system to be commissioned correctly for the warranty to be valid.

Surely if a 500litre thermal store is acceptable a 500lite UVC should also work.

 

You do NOT want a thermal store with an ASHP.  you need a much larger thermal store to get the same heat out as a UVC, and a thermal store needs the water storing at a hotter temperature which is a conflict with an ASHP.

[Gus Potter]

Volcane ...500 litres is a fair weight if not going on the ground floor or over a load bearing wall. Worth a quick thought if applicable to your plans.

 

Yes, if on say a first floor you can double up joists and so on but you still often need to get the pipework in.

 

PeterW's point also allows you to spread the loads out a bit.