Meter useful heat and electricity together
Measure sink flow and supply and return temperatures with matched, calibrated sensors. Meter compressor and agreed auxiliaries on the electrical side. Timestamp all signals so heat and power are integrated over identical periods.
Keep diagnostic variables
Source temperatures, source flow, compressor status, valve positions and backup-boiler output explain why performance changes. Production rate and product mix help distinguish equipment problems from a different operating schedule.
- Useful heat delivered
- Compressor electricity
- Included pump and fan electricity
- Source and sink temperatures
- Flow and operating state
- Backup heat
- Production and downtime markers
Agree the baseline before startup
Avoided gas is not simply heat-pump output divided by a nominal boiler efficiency. Define the displaced equipment, efficiency evidence, weather or production adjustments and treatment of simultaneous cooling benefits before reporting savings.
Calculate useful heat from matched signals
Useful heat on a water circuit is derived from flow, fluid properties and the difference between supply and return temperature. The sensors must be calibrated, correctly positioned and read over the same interval. Timestamp drift can create a false COP during changing load.
Electricity meters should cover the agreed compressor and auxiliary boundary. If source pumps or dry coolers sit outside the package meter, their consumption must be added before system performance is reported.
Commission the meters as part of the plant
Check flow-meter orientation, straight lengths, sensor pairing, scaling and data loss before the performance test. Compare calculated heat with a known operating condition where possible. A dashboard display is not evidence that the underlying measurement is accurate.
Keep raw interval data as well as monthly summaries. Raw signals allow investigation of cycling, defrost, boiler overlap, high return temperature and changing production.
Report performance with context
A monthly COP should be accompanied by useful heat, electricity, source and sink temperatures, operating hours, backup heat and relevant production. This shows whether a change came from the machine or from a different duty.
Savings reporting should use the agreed baseline and adjustment method. Avoided gas, simultaneous cooling and CAE savings may use different boundaries, so each calculation should remain traceable.
Sources
Primary and authoritative sources used for the material claims on this page.