Question for those using ASHP to cool

[willbish]

Is a buffer vessel a requirement?

 

I know it's not necessary for heating but is there something about different cooling that makes it essential? Or am I receiving duff info.

 

I was planning on using my 300mm slab as the 'buffer' dumping heat overnight during off peak hours.

 

In the summer months, when cooling, I appreciate there is the potential to cool the slab below dew point but I can't see that likely if just running for a few hours daily during peak PV production... And the thermostat is working.

 

Does a fan coil complicate matters though? Flow rate range and temperature range of the fan coil unit appear suitable for running directly.