Whole house ASHP system design

[flanagaj]

Can I ask those who have done whole house ASHP for DHW, heating and cooling who did your system design.  I have decided that I want UFH downstairs and ceiling mounted fan coil cassette units upstairs, but I want to install the system myself, except the ASHP or the parts that I cannot install myself.  I suspect that if I simply give my plans to a ASHP company and get them to supply and install, it's going to cost a fortune, hence why I am keen to get a system designed, so I know what is required.   

I could be over analysing this, and it's a simple case of understanding the heat loss calcs for each room and then simply purchasing the appropriate fan coil unit and running the pipework to the unit from the plant room and if appropriate putting in condensate drains.
 

Edited 20 hours ago by flanagaj

[JohnMo]

19 minutes ago, flanagaj said:

but I want to install the system myself, except the ASHP or the parts that I cannot install myself

Should be able to do everything yourself. Why can't you install the ASHP? 

 

Most installer will look blankly at when you mention cooling, especially when you utter UFH as cooling.

 

Condensation drains are only needed if you run below dew point, one real reason to do so, is if you don't size the fan coils correctly. If you size for a flow temp at around 16-17 then condensation isn't an issue.

 

 

 

[flanagaj]

15 hours ago, JohnMo said:

Most installer will look blankly at when you mention cooling, especially when you utter UFH as cooling.

This is exactly what I had recently with an ASHP installer.  With regards to your configuration.  Do you run your fan coils at a different water temperature to that of your UFH when you are in cooling mode?

[JohnMo]

21 minutes ago, flanagaj said:

Do you run your fan coils at a different water temperature to that of your UFH when you are in cooling mode

Have one fan coil in summer house and it runs same temperature as UFH. In cooling mode 16-17 degs, so have no condensation drains installed.

[flanagaj]

Just now, JohnMo said:

Have one fan coil in summer house and it runs same temperature as UFH. In cooling mode 16-17 degs, so have no condensation drains installed.

Ok, I think I was over complicating matters, by thinking I could run the UFH above dew point and run the fan coils at a much colder temperature to really make the bedrooms cool, but I suspect that running it at 16-17 degs is perfectly fine and will create a nice cold room for hot summer weather.

[JohnMo]

4 minutes ago, flanagaj said:

thinking I could run the UFH above dew point and run the fan coils at a much colder temperature to really make the bedrooms cool

You can do that, you basically connect to ASHP as two zones. Get the ASHP to control an electronic mixer to the UFH. Set the two flow temps in the controller and it will control fan coil and UFH flow temperature independently - note your heat pump generates the higher heating temp and lowest cooling flow temps of the two zones so you take a slight cop hit.

 

Although set up as two zones, you operate as a single zone, so no buffer or additional pumps needed.