Combining Air Con with an ASHP and MVHR system

[Indy]

Building a PassivHaus level new build (285 sq m)which will have MVHR, UFH throughout and the main house will be served by an ASHP. We also have a gym/store (40 sq m) building at the base of the garden and the plan is to have an Air/Air heat pump for the occasional use that building will get.

 

I also want to incorporate some form of active air conditioning in some of the bedrooms and the main living areas. Is this something that can be combined with the existing systems, or are we looking at dedicated units and ducting that are specific to the air con bits only? How does this generally work with the MVHR system?

Edited April 22, 2022 by Indy

[MikeSharp01]

You could run your ASHP in reverse and feed the cold water around the UFH to cool things down and perhaps add an online cooling battery to the MVHR but you cannot get much cooling at 'MVHR flow rates. JS Harris showed the the UFH cooling was effective in his build.

[joth]

Effective cooling via air requires (much) higher air flow rates than MVHR uses, so it's better to have independent "recirculating" air cooling device rather than use the MVHR for it.

I've fitted a Fan coil unit (FCU) to the ASHP cold water supply in order to cool one bedroom. It works well, but does need a much larger buffer tank than the UFH system was specified with.