Normalize the refrigeration baseline
Relate electricity to production, weather, room-temperature requirements, product pull-down and operating hours. Keep frozen, chilled and process loads separate where possible.
Industrial refrigeration energy audit checklist
Connect load, condensing, evaporators, defrost and infiltration before estimating savings.
This field checklist keeps product temperature, food safety, refrigerant safety, redundancy and production constraints visible. Measure a representative operating range; a single full-load point cannot explain seasonal or low-load control.
Other formats: print-ready PDFCSV data
Field data checklist
Collect load, plant and terminal conditions together.
| Field | Collect | Preferred resolution | Decision use |
|---|---|---|---|
| Plant electricity | Compressors, condensers, evaporator fans, pumps and auxiliaries | 1-5 minute trend for at least 14 representative days | System baseline, demand and auxiliary share |
| Refrigeration state | Suction/discharge pressure and temperature by pressure level | Aligned 1-5 minute trend | Lift, saturation conditions and control stability |
| Compressor operation | kW, capacity step/VSD, slide valve, starts, runtime and sequence | Aligned controller trend | Part-load efficiency and staging |
| Heat rejection | Ambient dry/wet bulb, condensing setpoint, fan/pump state and approach | Aligned 5-minute trend | Floating head opportunity within equipment limits |
| Evaporators | Room setpoint, air on/off temperature, fan state, valve demand and ice condition | 5-minute trend plus site inspection | Suction requirement, airflow and terminal control |
| Defrost | Start/stop, termination, heat source, fan delay and post-defrost recovery | Event log for 2 weeks | Unnecessary cycles and failed termination |
| Infiltration | Door open time, dock activity, seals, vestibules and traffic | Door log/video count by shift | Avoidable sensible/latent load |
| Product load | Throughput, entering/leaving temperature, product mix and pull-down schedule | Shift/daily record aligned to trend | Normalize core refrigeration load |
| Constraints | Food quality, temperature tolerance, hygiene, safety and redundancy | Approved operating specification | Stop conditions and permitted setpoint range |
Audit sequence
Review the refrigeration system as an interacting plant.
Reduce lift only within constraints
Test the effect of higher suction or lower condensing pressure using actual ambient, terminal demand, compressor envelope and stable control limits.
Resolve sequencing and low load
Compare compressor combinations at the same pressure levels and demand. Include condenser, fan and pump response rather than optimizing compressor kW alone.
Investigate defrost and infiltration
Use ice condition, termination evidence, door logs and room recovery. Do not shorten defrost or fan delay without protecting product and coil performance.
Define M&V before implementation
Preserve the same power, pressure, temperature, weather and production signals so the post-change comparison remains credible.
Overlap control
Recalculate the final system state before adding savings.
| Measures | Overlap mechanism | Aggregation rule |
|---|---|---|
| Floating head + condenser controls | Both change fan/pump power and condensing pressure | Model compressor and heat-rejection auxiliaries together |
| Higher suction + evaporator improvements | Coil cleaning, airflow and controls may enable the suction reset | Assign enabling work and calculate one final suction condition |
| Defrost optimization + infiltration reduction | Lower moisture load can reduce frost and future defrost need | Apply infiltration change first, then use the residual defrost schedule |
| Sequencing + compressor replacement | New equipment changes the optimal staging and part-load curve | Simulate the final equipment set and controls |
| Heat recovery + condensing optimization | Heat recovery may require a higher condensing temperature | Compare net compressor, auxiliary and displaced-heat effects by operating period |
M&V minimum
Hold product service constant while comparing energy.
Use matched or normalized periods with compressor and auxiliary kW, suction/discharge conditions, ambient wet bulb where relevant, room/product temperatures, production, door activity and control states. Document refrigerant charge or maintenance changes that can alter performance.
Sources and responsibility
System-level guidance with an explicit safety boundary.
Turn the collected data into a system-level screen.
Representative examples show the workflow only. Replace sample values and confirm local refrigerant, food-safety and engineering requirements.