UFH zones - staggered timings or all at once?

[climbinggeorge]

At the end of the build now so on the balancing/commissioning stage, we've got UFH upstairs - kitchen and living space 50m2 in 1 zone, and downstairs - bathroom and bedrooms 50m2 over 5 zones all driven by an ASHP.
We have solar panels but we don't get much sun through the windows until mid afternoon.

It makes sense to me make the most of the solar panels and warm the building when we have the excess energy ie 10 - 4 and then you are pre warmed for the evening within the building envelope.

 

I don't know how the ASHP works most efficiently, is it better to spread out heating for a few hours per zone over that 10 to 4 period ie office 10-1, hallway 11-2, bathroom 12-3 etc or just have all zones on for the 10-4 time frame?
Trying to get a grip on it before it turns cold
 

 

 

[Kelvin]

I experimented with the this in my previous house and concluded that heating every area at the same time using thermostats as limit stops was the best approach. 

[Conor]

No, you want the pump to heat the largest volume of water possible so it doesn't short cycle. 

 

And your solar panels won't be doing much at this time of year. My 4.5pkW array is struggling to hit 1kW. We will start running ours overnight on economy 7 very soon. Out background load is about 300W, so solar will cover that and any excess goes to the immersion. Other factor is a better COP during the day when the air is warmer, tho that advantage is diminishing day by day as the difference between night and day temps drops.

 

And fyi, we've only had ours on 3 times this year, and weren't really needed, just trying it out really. 

Edited November 3, 2022 by Conor

[JohnMo]

Merge your zones in to a single zone, so everything is on or off.  Areas at different temperatures require higher flow temps in the warm area as the heat tries to get cold areas at the same temperature.

 

Set up your Weather Compensation and use that. Set a 2 degree set ack at night.

 

Simple is best, long slow run times at low flow temps.

[climbinggeorge]

Thanks all.
I'll put short cycling on my research list for this lunch to find out more about that, and stop trying to be clever with the timings