Heat pump+PIV: enough? Or are fan coil units necessary?

[Garald]

As people who are following my house saga know, we are planning on having a reversible air-water low-temperature heat-pump, with

 

(a) radiators (a mixture of some existing ones and taller ones adapted to low temperatures),

(b) a ducted PIV system, providing cooling, supplementary heating, air filtration, etc.

https://www.vmi-technologies.com/wp-content/uploads/2020/09/aquarea-purevent-visionR.pdf

 

The PIV is Panasonic, the heat pump is Hitachi, hopefully they won't hate each other.

(We are currently going for Hitachi because that's what the installer says. Why that person in particular for the installation? Our situation is a bit funny (I've bought an outhouse adjacent to my place, and undone the internal wall separating the two, so that I can install the heat-pump there and not annoy the neighbors. That constrains us to either (a) a heat-pump designed to be used in the inside (the pickings are slim; we've basically gone down to a single, relatively little-known manufacturer (Amzair) and the installer isn't getting back to us) or (b) a heat-pump designed for the outside, and an installer willing to install it in the ambiguous place we've got now (basically a normal-sized door leading to the outside and the space immediately behind it). If you know of someone knowledgeable in the Paris area willing to install a Panasonic heat-pump in such circumstances, please tell me.)

 

OK, to the point. It sounds like I will be very cozy in winter. However, as the manufacturer's manual itself says, while this system provides pretty good cooling, it doesn't provide a _lot_ of cooling. Fine - AC users are seen as antisocial elements in France anyhow. But what about when the temperature heats 40C? I'm less concerned about the long, south-facing library (which will be protected by shutters and awnings) than I am about the attic where we will likely be sleeping, in part because there will be plenty of skylights - with shades from the outside, but still.

 

So: given that we are sprucing up the heating system in general (installing new radiators, getting a good clean-up, fixing any irregularities, etc.), is it a good idea to install an FCU unit or two, or to at least prepare for the eventual installation of such?

 

I'm a newbie, so please instruct me. Would cold water flow along the same heating ducts as hot water does in winter? Or would an entire supplementary system of pipes be necessary?

 

Is installing FCU when one already has VMI with cooling something completely backwards - a waste of energy and/or money?

 

(I realise there are several interrelated questions - tease them apart all you want.)

 

There's a fan coil unit by Panasonic itself (https://www.aircon.panasonic.eu/GB_en/product/aquarea-air-radiators-1-1/). No idea what the appropriate power is.

 

 

[SteamyTea]

May as well fit them while the places is a mess, better than living with regret.

Edited November 21, 2022 by SteamyTea

[JohnMo]

2 hours ago, Garald said:

There's a fan coil unit by Panasonic itself (https://www.aircon.panasonic.eu/GB_en/product/aquarea-air-radiators-1-1/). No idea what the appropriate power is.

There not cheap, just looked at the price of the 1.1kW £842 each

[Garald]

1 hour ago, JohnMo said:

There not cheap, just looked at the price of the 1.1kW £842 each

 

True. But what do we need to do now so that we can fit them in later if needed?

[Garald]

3 hours ago, SteamyTea said:

May as well fit them while the places is a mess, better than living with regret.

 

Well, the alternative is getting everything ready so that we can get them later and install them painlessly if needed. Is this naive? What needs to be done?