Cold room sizing in five minutes — load, system, simulation in one tool
By DigiEntropy Engineering · 2025-12-28 · 6 min read
Cold room sizing has always been a multi-tool workflow: a load spreadsheet, then a compressor selector, then a simulation. The DigiEntropy Cold Room page collapses it into one — and you can go from blank to specified system in about five minutes.
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 sizing has always been a multi-tool workflow. You start with a load calculation in a spreadsheet (transmission + infiltration + product + internal + safety margin), then you take the result to a compressor selector (vendor software, usually), then you cross-check with an operation simulation (custom or generic). Each handoff loses information; each tool has its own conventions; each iteration takes hours.
The DigiEntropy Cold Room page collapses all three into a single page. Five minutes from blank to specified system.
5 min - from blank to specified system - load, compressor and energy on one page
Total: 5 minutes for a well-specified cold room with a confirmed compressor and an energy estimate.
3 tabs - that share state - Load, Refrigeration System, Operation Simulation
The page is organised into three tabs that share state — change an input in any tab, the downstream tabs recompute.
90 s - to fill in Tab 1 - for a typical food-storage cold room
Most engineers can fill this in 90 seconds for a typical food-storage cold room.
10-15% - defrost + safety margin - on top of the heat load
Defrost + safety margin — typically 10-15% on top.
3 s - for the year-long simulation - hourly, on your location's weather
Tab 3: enter your location (city autocomplete) and electricity tariff. The simulation runs in 3 seconds.
70% - load for >20% of hours - means the compressor is undersized
Tab 3 shows part-load distribution. If the compressor runs >70% load for >20% of hours, it's undersized.
10 years - of annual energy × tariff - a lifecycle cost number for bid prep
Bid prep — annual energy × tariff × 10 years gives a defensible lifecycle cost number that wins bids against competitors quoting upfront cost only.
What it does
The page is organised into three tabs that share state — change an input in any tab, the downstream tabs recompute:
Switch the tabs below to walk through each one:
Tab 1: Load Overview
The classic heat-load calculation broken into its standard components:
- Transmission load — heat conducted through walls, floor, ceiling. Inputs: dimensions, insulation R-value, ambient + room temperatures.
- Infiltration load — air exchange through door openings and seals. Inputs: door area, opening duration/frequency, climate zone.
- Product load — sensible + latent + respiration. Inputs: product type (catalog), mass throughput, entry/exit temperatures.
- Internal load — lighting, people, motors, packaging. Inputs: lighting density, occupancy hours, motor count.
- Defrost + safety margin — typically 10-15% on top.
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