Efficiency 360: From a Refrigerant Shortlist to a Priced System in Six Steps
By DigiEntropy Engineering · 2026-09-06 · 9 min read
A walkthrough of the six Efficiency 360 steps — refrigerant, compressor, part-load architecture, a simulated day, 15-year cost, and the designed system you can price — with the real numbers each one produces.
About this post — Authored by an AI assistant using DigiEntropy's polynomial corpus, the universal compressor predictor, and the project's chart-generation tooling. Charts are produced by Python scripts that read the same database the live site queries; tables and formulas are pulled from the same engineering modules. Findings reflect the project's current dataset and methodology — send corrections or deeper questions to admin@digientropy.com.
Choosing a compressor is not one decision. It is six, and they pull against each other. The refrigerant with the best COP may have three models on the market. The cheapest machine may be the one that cycles itself to death. The most efficient one at full load may be the worst at 30 %, which is where it will actually spend its life. And the machine is not the system — a compressor with no condenser, evaporator or expansion valve is not something anyone can buy.
Most of the time those six decisions get made in six places: a refrigerant table, a manufacturer's selection tool, a spreadsheet, a second spreadsheet, a quote request, and a phone call. Nothing carries forward. Change the refrigerant and you start again.
Efficiency 360 is those six decisions in one place, in order, each one locking its answer into the next. Here is what each step actually produces.
3.72 - R744's COP at the Step 1 duty - GWP 1, and only 3 models
R744 leads on COP at 3.72 with GWP 1 — and offers 3 models.
65 % - more for the same machine on an inverter - it holds COP 2.71 at half load
Putting the same machine on an inverter costs 65 % more and holds COP 2.71 at half load.
48 - starts a day at fixed speed - the inverter makes one
Fixed speed: 75.1 kWh a day, 48 starts, in band 70 % of the time, €15.28.
17 % - less energy a day on the inverter - and €2.58 a day cheaper
The same compressor on an inverter: 62.4 kWh, one start, in band all day, €12.70 — 17 % less energy and €2.58 a day cheaper.
€80,235 - what a 20 % better COP is worth - 15 years at €0.204/kWh
The same duty over 15 years at €0.204/kWh. A 15.0 kW draw costs €401,177 of electricity. A machine 20 % better costs €320,942. The COP difference alone is worth €80,235.
2.29 - COP of the solved loop in Step 6 - 19.15 kW of cooling for 8.38 kW
19.15 kW of cooling for 8.38 kW at the shaft — COP 2.29, balanced at −17.1 °C and 39.8 °C, with the capacity balance closing to 0.1 %.
Step 1 — Choose the refrigerant
You give it a duty: cooling or heating, a temperature band, a capacity. It ranks every refrigerant your filters allow by real COP at that duty — not a handbook number, but the average across the compressors that exist for it.
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