Great stuff, you can read directly from the SDM120s via emonHub to get the data straight into Emoncms & MQTT: https://guide.openenergymonitor.org/integrations/emonhub-interfacers/#reading-from-a-sdm120-single-phase-meter
We usually use Sontex or Kamstrup heat meters in our ASHP monitoring bundle, however emonHub can also read from Sharkey. The 2.5m3 is a good choice, I’m assuming you’ve seen our choosing a heat meter page?
As confirmed by @Zarch the default Sharkey MBUS ID is 25 therefore the following config will work:
[[MBUS]]
Type = EmonHubMBUSInterfacer
[[[init_settings]]]
device = /dev/ttyAMA0
baud = 2400
[[[runtimesettings]]]
pubchannels = ToEmonCMS,
read_interval = 10
validate_checksum = False
nodename = mbus
[[[[meters]]]]
[[[[[heatmeter]]]]]
address = 25
type = standard
You will need a couple of 3/4" female BSP to 28mm compression irons e.g Brass Compression 28mm x 3/4 inch Straight Adaptor Female CxFi
and a 1/2" female 28mm compression branch tee for the temperature sensor pocket on the flow, the heat meter will fit on the return e.g Compression Female Branch Tee 28mm x28mm x 1/2"