It is a Daikin Alttherma 3 - (4KW). Particularly I am looking to understand how to effectively utilise the heatpump at lower flow temperatures thereby presumable get better COP. I don’t have any advance monitoring of the system. Just the trusty day by day kwh usage to understand the impact of any changes.
So far from my research, things that make the radiator usage very effective
Good predictable lock shield valves - IHI regutec. So you control the flow better and determine delta T of a radiator without monitoring tools.
Radiators that are bigger as possible for effective heat dissipation at lower flow temperatures.
Anything else that can be done to improve the radiator setup? What have you tried changing and did it have the intended impact?
We run one rad, a Type 33 1400 X 600 in annexe loft room.
The rest of the property is underfloor heating.
We had a Type 22 in there at first.
Of course the MCS calcs said the Type 22 would be big enough🙄… Heat loss of the room Vs LWT of 50°C flow at -3!
They wouldn’t listen so we accepted it and did that rad ourselves.
Don’t underestimate the weight of Type 33 rads!
The Type 22 rad was getting the room to 18C or so at the LWTs we use.
Even at the coldest in Jan / Feb we don’t go above 33C or so LWT.
That’s a rad delta T of just 13C for 20C room.
It’s a sitting room so we wanted 21+ in there.
We did the calcs for room at a rad delta T of 10C.
Using a very helpful rad output table that showed rad sizes Vs output from delta T of 10C and upwards.
Going from type 22 to type 33 increased the performance perfectly.
The room is always around 21 now. No complaints.
Added: I’ve seen some using fans to assist heat distribution from rads. I tried a normal summer fan blowing from the side of the radiator behind it as a test.
It did raise the room temp a degree or so.
You can get or make bespoke low voltage fan arrays for the job that fit underneath and assist the convection.
Can be quiet enough apparently..
The regular lock shields do not control the flow of water evenly corresponding to the turns. They are either no flow for most of the turns and sudden ALL flow in the last of the turn. This means it is difficult to balance them. This article with a video in it explains it well.
This is exactly our scenario as well, Type 22 rad struggling to hit 21. Somewhat balanced now by tweaking lockshields. Yet to test it under similar conditions (outdoor <5).
Great to hear . Might I ask what was the estimated heat loss of this loft room as per the survey?
Ours is a small room and I think this isn’t a problem but good point.
The heat loss from the survey was 872 Watts, with the 600x1400 K2 rad output quoted as 1138W, 50C at -3C.
21C room target.
That rad at my delta T of around 10 to 13C gives out around 612 to 650W.
It actually performed better than I expected.
Perhaps the room is better insulated than the survey would indicate..
The various room heat loss websites calculator I tried have been 940W and 1100W loss.
The K3 600x1400 rad output is around
1000 to 1100W depending on exact input temps.
. Might I ask what was the estimated heat loss of this loft room as per the survey?