System Simulator — drag-and-drop refrigeration loop design
By DigiEntropy Engineering · 2026-02-07 · 8 min read
Compressor + condenser + evaporator + expansion valve + pipes — the full refrigeration loop simulated against vendor polynomials and a closed-loop solver. System Simulator is where you go after Cold Room when the loop topology is the unknown.
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. Cold Room sizes a compressor against a heat load at standard SST/SDT. Real systems have evaporators, condensers, expansion valves, line sizing, and pipework that all shift the operating point away from "standard." A 25 kW compressor sized at -10/40 might land at -12/45 once the actual evaporator and condenser are in the loop, dropping capacity by 5-10 %. To capture that, you need a system-level simulator that solves the loop simultaneously. System Simulator does that — drag components onto a canvas, the closed-loop solver iterates SST/SDT to balance compressor capacity against evaporator + condenser duty + pipe losses. What it solves vs Cold Room Cold Room System Simulator ------ Compressor sized at standard SST/SDT SST/SDT solved from condenser + evaporator + pipe losses Evaporator + condenser treated as "given" Picks evaporator + condenser from catalog and balances duty Single load profile (room) Multi-component loop 5-minute selection workflow 15-30 minute design workflow Output: compressor + annual energy Output: full loop + cycle states + per-component duty Use Cold Room when the load is the unknown. Use System Simulator when the loop topology is the unknown. Building a loop in 3 minutes 1. Drag a compressor onto the canvas. The slot opens a Choose Compressor Model picker — type "4HE-25Y" and pick. 2. Drag a condenser. Picker offers Güntner, Eden, and the catalog of cross-brand condensers. Capacity matches against the compressor's heat rejection requirement. 3. Drag an evaporator (unit cooler). Same pattern. The slot constrains the candidate list to evaporators sized for the room/load. 4. Drag an expansion valve. TXV for fixed superheat, EXV for adaptive. The catalog hides obviously-wrong sizes. 5. Click Calculate. The solver iterates SST/SDT until compressor capacity = evaporator duty = condenser heat rejection. Line components matter more than people think Solenoid valves, sight glasses, filter driers, EXVs/TXVs — line components rarely fail when correctly specified but they're the single biggest source of in-service failure when undersized. A solenoid valve sized for 100 % cooling capacity at 2 K…