F gas A2A and A2W

[Oz07]

Talking to a plumber tonight. He is F gas certified. He was explaining the difference with these heat pumps to the standard ones to me. It's all a bit beyond my understanding. Anyway I was asking him if I could have wet UFH on GF then air to air units upstairs to do heating if needed and cooling in summer, also probably 1 or 2 air units downstairs to cool. All off 1 outdoor unit. I think he is more in with Daikin and said they are bringing out something soon, however Samsung appear to do the perfect solution with the TDM plus / climate hub. Outdoor pump, pre plumbed cylinder and air to air units. It looks good, no doubt very costly?! Does anyone have any experience with this set up. Seems simpler to a luddite like me. I suppose cost will be the trade off for simplicity i've no doubt others like @JohnMo can knock something up just as good performance wise for a lot less dough, maybe even have 2 seperate outdoor units. It's just beyond my pay grade though. I wonder what cost would be for this and 5 or 6 indoor air con units and the cylinder. https://samsung-climatesolutions.com/gb/b2c/our-solutions/home/heat-pump-solutions/heating-cooling/tdm-plus.html

[SimonD]

Lots of ifs and buts on this one. There are only really three practical ways of moving the heat into and out of the building: water, air, refrigerant. Air specific heat capacity is poor so you need lots of volume and flow, refrigerant needs its own specific pipework, qualifications etc. with lots of limitations to things like pipework length. Water is definitely the most effective way to move the heat. The aircon units will probably also need condensate drainage so added complexity there.

I don't think the solution is that simple, or not as simple as the Samsung marketing department makes it look. Maybe okay for a new build, but for a retrofit? I'm not so sure. Like with all these things, the complexity lies more in the cooling than in the heating, especially if you want aircon type cold.

[JohnMo]

The F gas solution doesn't look cheap, may be wrong. Could be a good system, but I would go A2W and have fan coils (water to air) in bedrooms and normal wet UFH.

 

A pragmatic design could be pretty simple. Design for heating, accept cooling may not be perfect but way better than not having cooling. UFH will make house feel way cooler than the air temperature is. The fan coils in bedrooms will leave rooms for a comfortable sleep.

 

First job is looking at heat loss and sizing an outdoor unit. Then room by room heat loss. Design UFH (not some cut and paste job by UFH suppliers). Size fan coils to provide room heating at under 30 degs. Then run everything as a single zone. Fan coils will modulate fan speed to keep room temperature stable. 

 

The above assumes you are talking about a low energy house.