Panasonic ASHP

[marshian]

Went to my friends house this weekend - fairly large bungalow with a ASHP set up

 

Looked at the heat pump and was really surprised to see the primary pipes are tiny (like microbore size) I was expecting 28mm pipework from the ASHP to inside

[Nickfromwales]

39 minutes ago, marshian said:

Went to my friends house this weekend - fairly large bungalow with a ASHP set up

 

Looked at the heat pump and was really surprised to see the primary pipes are tiny (like microbore size) I was expecting 28mm pipework from the ASHP to inside

Eh? The HP has 1"1/4 unions on the back, so I fit 1"1/4 female unions > 35mm compression, with 35x28mm internal reducing sets or soldered reducers, and then 28mm pipe (minimum) to the plant room and UVC.

 

Something very wrong there...??

[Nickfromwales]

This is the last Panasonic I fitted. 
 

 

Are you confusing a high temp split with refrigerant gas lines vs wet mono block A2W unit? 

[dpmiller]

defo sounds like refrigerant lines heading into the house...

[JohnMo]

Something like this

[marshian]

10 hours ago, Nickfromwales said:

This is the last Panasonic I fitted. 
 

 

Are you confusing a high temp split with refrigerant gas lines vs wet mono block A2W unit? 

 

I'm guessing it's high temp split with refrigerant

 

I only noticed the pipe size because the insulation is also quite small and is in a poor state in places - guess that might be impacting efficiency?

[Nickfromwales]

1 hour ago, marshian said:

 

I'm guessing it's high temp split with refrigerant

 

I only noticed the pipe size because the insulation is also quite small and is in a poor state in places - guess that might be impacting efficiency?

They may have used insulation that's not UV tolerant/exterior grade.

[Beelbeebub]

Is it a split system? The "primary" pipes will be small bore copper taking the refrigerant inside to a box which then   transfers the heat to the water.  The outside unit is no different from a standard aircon unit. They seem to be falling out of favour in the UK but apparently are the more common implementation on the continent. 

[marshian]

28 minutes ago, Beelbeebub said:

Is it a split system? The "primary" pipes will be small bore copper taking the refrigerant inside to a box which then   transfers the heat to the water.  The outside unit is no different from a standard aircon unit. They seem to be falling out of favour in the UK but apparently are the more common implementation on the continent. 

 

I think it must be

[marshian]

So are advantages of split units using refrigerant things like no glycol/antifreeze valves, no defrosts and a higher flow temp is possible than A2W Heat pumps?

 

The COP from memory was high 3’s in middle of winter and high 4’s to low 5’s in shoulder seasons

 

House is a fair size (so will cost to heat) but to me the energy bills over winter are eye watering

 

it was built 6 years ago to regs UFH throughout with additional big towel rails in all the bathrooms

 

what concerned me from an efficiency perspective was the buffer, number of pumps in the system and thermostats in every room

[JohnMo]

32 minutes ago, marshian said:

no defrosts

They still defrost 

33 minutes ago, marshian said:

no glycol/antifreeze valves

I have neither on my monobloc either 

33 minutes ago, marshian said:

The COP from memory was high 3’s in middle of winter and high 4’s to low 5’s in shoulder seasons

No difference from a monobloc 

34 minutes ago, marshian said:

what concerned me from an efficiency perspective was the buffer, number of pumps in the system and thermostats in every room

Yep you will knock 1 to 2 off SCoP easily.

 

I changed our logic so the only circulation pump switched off when the compressor was off. The blue dots represents CoP for that day. No changes made other than pump logic. Guess when I changed the logic. Dread to think what second circulation pump and buffer effect would do.

[SteamyTea]

Is one advantage of a split system, in the UK, the 0.6m³ rule (though this may have been relaxed with recent planning rule changes).

Means you can get a larger ASHP because the outside unit is all radiator and fan, and not all the other gubbins like heat exhangers, pumps, electronics etc.

 

I also think that a split gives a slightly better CoP, but probably a marginal difference.

The inside part of a split system does not have to be in the actual house, can easily be fitted into an outbuilding, or a dedicated 'box' on the side of the house.  Really just depends on how easy it is to run the main 'wet' pipework.

(I have often thought that gas boilers should be outside in a cabinet).