ASHP choices

[Marvin]

Having been clearly advised of the stupidity of trying to install a ASHP big enough to "heat the house", in the house, ( did I mention the 800mm diameter ducting it would need?) You will all be glad I have moved on!

 

I have already had some good pointers from Buildhub posters - thank you! - and am now looking at the set-up.

 

Are there any ASHP air to water units that will do cooling? If so anybody have any feedback on how the use of the cooling has gone, for an air to water system?

 

The ASHP would only need to be 1 of the smaller ones. 4kWish. Input.

 

Thanks

 

Marvin

 

 

 

[joe90]

As far as I am aware they are all capable but only some advertise it. My Kingspan unit (Carrier) will but it ain’t got that hot yet!!!!. Read jeremy Harris blog, his has the same unit as me and he reversed engineered his to do it.

[IanR]

I have a Nibe with the cooling add-on. I cool the buffer which is then sent to UFH and MVHR heat exchanger.

The UFH is very effective for cooling, in my set-up, the MVHR less so, as you would expect.

I have other processes to help cooling so the ASHP/UFH doesn't do it all on its own, which probably helps.

First step is to even out the energy in the slab, to move heat from solar gain areas to the rest of the house by just circulating the UFH.

Roof vents will also open to dump warm air, if outside temp is lower than internal.

I also have external blinds to restrict solar gain if needed.

If the "passive" measures are insufficient, then the ASHP starts to cool. I have it stepping in quite quickly so that it is trying to maintain a temperature rather than bring a temp that sailed 10 degrees passed the desired temp.

In those circumstances, it is effective.

 

[ragg987]

I went with a small Hitachi ASHP (7kW nominal). It just required a dip switch to be set to enable cooling, the controller then recognised the mode and it can be set / programmed same as heating. I also needed to buy a couple of bits ("cooling kit"), essentially condensation control - insulation for the circulator pump and a drip tray with drain pipe.

 

I was told by Hitachi that they do not advertise the mode, something to do with regulatory approvals.

 

In practical terms it is very helpful at reducing the internal temperature, and it helps that the MVHR goes into heat-exchange mode when outside temp is very high thus keeping the cool air in the house. We had to add shading into the mix as our double aspect lounge has too much solar gain. With all 3 measures we were quite comfortable last summer in those weeks when we nudged 30C.

[ragg987]

23 minutes ago, IanR said:

I have it stepping in quite quickly so that it is trying to maintain a temperature rather than bring a temp that sailed 10 degrees passed the desired temp.

Ditto - takes a few hours to be effective as reliant on UFH, so best to run it early and long. Don't forget all people, applicances etc in the house are adding to the heat load.