Find the exact axes and reference point
A performance table may use source inlet, evaporating temperature, sink outlet or condensing temperature. These are not interchangeable. Confirm flow rates, temperature differences, refrigerant, compressor speed and whether values include auxiliaries before reading capacity or COP.
Interpolate carefully
If the proposed duty lies between published points, interpolation may support early screening. It should not replace manufacturer selection. Do not extrapolate beyond the envelope or assume that maximum temperature and maximum capacity occur together.
Ask for the whole operating range
A plant rarely stays at one point. Request capacity, power, COP, discharge temperature and limits at design, minimum source temperature, maximum sink temperature, part load, startup and anticipated fouling conditions. Record the software version and date of every selection.
Separate capacity from efficiency
A machine can remain inside its temperature envelope while losing capacity or drawing more power. Read heating output and electrical input at the same point, then calculate or check COP using the stated boundary.
Maximum sink temperature, maximum capacity and best COP rarely occur together. Database fields should therefore be treated as search aids rather than combined into an assumed duty.
Create a duty-point schedule
List the normal point, coldest source, hottest sink, minimum load and any startup or cleaning condition. Request source flow, sink flow, heating capacity, compressor power, included auxiliaries and operating limits for each row.
Attach the supplier selection date and software version. A later refrigerant, compressor or control revision can change the result even when the model name remains the same.
Interpolate only inside the evidence
Interpolation between nearby published points can support a screen when the axes and configuration are identical. Extrapolation beyond a compressor envelope or towards a higher sink temperature is not defensible.
Where public data is incomplete, ask the manufacturer rather than infer a value from the model number. The model index marks that absence explicitly.
Sources
Primary and authoritative sources used for the material claims on this page.