Heat pumps. Any negative points about 3 phase?

[JohnMo]

7 minutes ago, Barnboy said:

outside humidity has been between 70% and 100%

But when air is heated the dew point moves. We have a heated summer house it has dMEV fan, humidity inside hasn't been above 40% for that last month. We have bearly had a dry sunny day in the last month humidity outside closer to 100% most the time.

 

Are you heating the house?

[Barnboy]

13 hours ago, JohnMo said:

Change the trickle vents to humidity activated one, but only in dry rooms (bedroom, living room etc).  Seal up any in wet rooms

https://www.ironmongerydirect.co.uk/product/trimvent-xr16-upvctimber-window-vent-recessed-352-x-16mm-white-906766

I think that these are the trickle vents that we have, I've looked and can't seem to find a  humidity controlled replacement, I think that they are the cheapest the Joinery company could be bothered to find.

[Barnboy]

Only source of heat is from body, cooking and showering.

[JohnMo]

11 minutes ago, Barnboy said:

Only source of heat is from body, cooking and showering.

There's your second issue, not just ventilation, no heating.

[JohnMo]

13 minutes ago, Barnboy said:

https://www.ironmongerydirect.co.uk/product/trimvent-xr16-upvctimber-window-vent-recessed-352-x-16mm-white-906766

I think that these are the trickle vents that we have, I've looked and can't seem to find a  humidity controlled replacement, I think that they are the cheapest the Joinery company could be bothered to find.

First hit in Google

https://www.bpdstore.co.uk/glidevale-energy-saver-humidity-sensitive-trickle-ventilator/p/182

[Barnboy]

9 hours ago, JohnMo said:

First hit in Google

https://www.bpdstore.co.uk/glidevale-energy-saver-humidity-sensitive-trickle-ventilator/p/182

I've already looked at these, they're too long. If they would fit over the recess left from mine they still wouldn't fit as I had to make a recess to be able to get enough insulation into the reveal.

[JohnMo]

These are 402mm long

https://www.shop24glasgow.co.uk/en/windows-accessories/836-manual-trickle-vent-vt600.html

 

 

[Nickfromwales]

So, 3ph heat pumps, back on topic folks!!!!!

[saveasteading]

10 hours ago, Nickfromwales said:

, 3ph heat pumps, back on topic folks!

It's been an interesting detour. 

But back to the early responses. My hunch is still that 3 phase would be the less complex "go to", rather than very clever, but complex, inverters from single ph to dc then to 3 ph which must carry some cost and increased fault risk.

 

[Nickfromwales]

41 minutes ago, saveasteading said:

It's been an interesting detour. 

Yes, but the fleas come with the dog, lol.

[-rick-]

11 hours ago, saveasteading said:

But back to the early responses. My hunch is still that 3 phase would be the less complex "go to", rather than very clever, but complex, inverters from single ph to dc then to 3 ph which must carry some cost and increased fault risk.

 

As I said in my first reply, pretty much ALL heatpumps are now inverter driven. So if you want to avoid an inverter you are likely going to have a bit of work to do to find a heatpump and if you succeed it will be much less effficient than an inverter driven one. Non-inverter heatpumps can't modulate, only on/off cycle.

 

Whatever you do (single or 3 phase) get an heatpump that can modulate to a very low output. You likely won't need anywhere near tha max calculated demand for much of the year.

Edited February 15 by -rick-

[SteamyTea]

I like to think of an inverter as a CVT gearbox. 

Most of the time you can drive a car in third gear, be a bit hard to get going, max speed will be limited, and fuel consumption will be dreadful.

Generally electronics are reliable, the biggest problem is replacement parts are silly money, we had a board changed in the dish washer at work, the problem was a relay, 20 quid part. The repair was over £1200, for a secondhand board. They kept our broken one which I could have repaired.