@matthannon do bear in mind theyâre a bad idea (TRVs in general with the exception of bedrooms) with an Air to Water #A2W based (i.e. radiator/UFH based) #HeatPump so shouldnât be used, nor pushed.
An open circuit that doesnât restrict flow is very very important to get the efficiency levels theyâre rated & good for.
Take a look at #HeatGeek (Adam Chapman) @petereastern , @kenbone , @stevewebster56 , Nathan Van Gambling for references to this
@matthannon @petereastern @kenbone @stevewebster56
I had the Honeywell EvoHome smart radiator setup on all radiators prior to this summer when I got my Daikin #HeatPump installed by Octopus đ Energy.
They also agree with the no smart TRV (or set all to max) approach & instead balance the radiators and UFH.
All controls (incl. smart TRVs) are now gone, with the system running brilliantly efficiently on pure weather compensation control only.
@matthannon @petereastern @kenbone @stevewebster56 I wouldnât personally (the Smart TRV upgrade)
The technical âwhyâ is that you need a min amount of water & emitters (rads, UFH) in the system (ie the TRV hasnât turned off!) that matches min modulation heat output (W) of the heat source (gas or #HeatPump )
Not doing this leads 2 âshort cyclingâ where the unit hasnât got anywhere to send the heat so turns off, yet thermostat says it needs heatâŠ
@matthannon @petereastern @kenbone @stevewebster56
Short cycling is bad for a gas boiler (but no-one cared when gas was cheap).
Short cycling is *terrible* for #HeatPump efficiency, and the solution is to avoid zoning/using TRVs unless really required (bedroom, south facing glazed room), and where the rest of the system meets the minimum water and emoter output of the heatpump.
Electric price compounds this and is unforgiving.
@matthannon @petereastern @kenbone @stevewebster56
To add to this, for a water based #HeatPump restricting the water and emitters can have the effect of driving up the âflowâ temperature (the minimum heat output has to be delivered somehow) to compensate.
If you didnât know: #HeatPump âflow temperatureâ is critical to efficiency (and therefore ÂŁÂŁ).
Higher flow temperatures lead 2 higher input power (electrical Watts) which you pay for.
@matthannon @petereastern @kenbone @stevewebster56 have you considered doing an episode for #LocalZeroPod to aid people with best practices for #HeatPump ?
I see youâve had Nathan van Gambling and Adam Chapman on before, but would be worth having even a segment on this.
Remember: #HeatPump efficiency (from being able to lower flow temperature from say installing more or bigger radiators) is equivalent of other energy saving measures. Subtle.
@matthannon @petereastern @kenbone @stevewebster56
I found one of the really good field trial (Ireland, so very close match to our climate) reports that @paulkenny was involved in and I read a few times to digest.
Worth a look, and again this also covers TRVs amongst other great best practice and conclusions.
Hope the share is useful to others.
@matthannon @petereastern @kenbone @stevewebster56
The other thing worth mentioning is that the tado (or other makes) control wonât be able to effectively or efficiently control a #HeatPump itself.
They send on/off signals to the heat pump which are terrible for efficiency (but will work with higher running costs)
Best to remove/not install 3rd party control/thermostats with #HeatPump
Stick to the supplied manufacturer controls basically!
@matthannon @Stephencrown @petereastern @stevewebster56
We install TRVs, but we also make our systems open loop. So the main reason for TRVs is for overshooting, the main heat sources ie, the big areas on the ground floor, we won't use the heads at all.
Prof Matt Hannon
Stephen Crown
Peter Miller
SellaTheChemist
Bones
Dominic