The data on HPM would deliver maximum value to the widest range of users if we had separate data feeds for each of the “relevant” parameters, which could be used in different combinations to report against various System Boundaries (i.e. H4 versus H3 / H2 / H1), depending on what a particular researcher is most interested in.
The catch is, there are quite a lot of potentially-relevant parameters - and some of them are difficult to measure individually. I recently posted a diagram on this other thread, created by the SEPEMO research team (who are generally considered the authority when it comes to System Boundaries). That diagram shows:
- Mandatory Sensors:
- 2 heat meters
- 5 electricity meters
- 7 temperature sensors
- Optional Sensors:
- 4 more heat meters
- 4 more temperature sensors
You’d have to be really interested in monitoring to invest in 6 heat meters (plus each one restricts the flow slightly so reduces efficiency) and inserting MID-certified electricity meters for pumps and auxiliary heaters which are factory-integrated would invalidate the manufacturer warranty.
So we have to be pragmatic about what level of granularity is achievable and live with the fact that some of the parameters are going to be aggregated together at the point of measurement. In some cases (as with your Booster Heater example) it’s possible to use other information sources to dis-aggregate the readings, which I think is helpful; I’d have done the same if my booster heater was ever used (and might still do it, just in case it kicks in).
Then there’s the fact that system configurations vary between manufacturers and installations:
- Sometimes everything’s integrated into a single heat pump unit
- But some manufacturers will provide information which helps to dis-aggregate some readings
- Sometimes there’s an Outdoor unit and a separate Indoor unit, containing pump(s) and heater(s)
- In principle, these could have separate electricity metering without impacting any warranty
- Sometimes there’s underfloor heating, usually with a separate pump and thermostat
- Often that pump is remote from the heat pump and might be on a different electrical circuit
- Sometimes some of the components are installed in unheated loft or garage spaces
- This influences whether the heat ‘losses’ are retained as heat in the house or lost to the outside
The question then is what does that mean for the data feeds used by the MyHeatpump App which underpins HPM. It’s important not to exclude the installations which use the basic monitoring package of a single heat meter and a single electricity meter (as long as it’s clear which readings those meters are aggregating) but it would be good to also cater for more advanced monitoring installations which are able to separate out (some of) the parameters - a bit like we do for CH and DHW currently. It’s covering all the variations which complicates the coding though.