In 2022, Diego Ramirez, a shrimp exporter in Guayaquil, Ecuador, purchased container cold rooms from us. His logic was simple: "Shrimp spoils, so colder must be better." He put everything — fresh chilled shrimp that needed refrigeration and shrimp meat that needed freezing — into −25°C deep-freeze units.
Six months later he did the math: his electricity bill was about 40% over budget. Worse, the chilled shrimp had been freezer-burnt at −25°C, losing texture and appearance after thawing, and customer complaints rose. When we assessed the site, we found his products actually needed three different temperatures: chilled at 0–4°C, shrimp meat frozen at −18°C, and some premium shrimp meat quick-frozen at −35°C. Storing it all at −25°C wasted power and damaged the goods.
This is a classic "temperature-zone mismatch." A container cold room is not about "colder is better" — it is about matching temperature to product category. Using Diego's remediation case, this guide lays out the three temperature zones, compressor configurations, energy differences, and selection logic.
| Zone | Temperature range | Typical compressor | Insulation thickness | 40HQ daily energy |
|---|---|---|---|---|
| Chiller | 0 ~ +4°C | Single-stage | 100 mm | ≈6–9 kWh/day |
| Freezer | −18°C | Single- or two-stage | 120 mm | ≈12–15 kWh/day |
| Deep freeze | −25 ~ −35°C | Two-stage / cascade | 150 mm | ≈25–35 kWh/day |
Ahmed, an ice cream importer in Riyadh, Saudi Arabia, needed long-term storage at −25°C. This is precisely the legitimate use of a deep-freeze unit. We configured a cascade refrigeration unit with 150 mm insulation, plus anti-condensation door-frame heating to prevent frame frosting in hot, humid conditions. Two years on, the internal temperature held steady at −25±1°C, with no softening and no ice crystals in the product.
There is a second-order effect worth understanding: temperature also drives equipment sizing. A −35°C deep-freeze unit needs a cascade or two-stage system, larger condensers, and thicker insulation than a −18°C freezer — differences that show up in both the purchase price and the footprint. Getting the zone right is therefore not just an operating-cost decision; it determines which compressor architecture, which insulation build, and which door and frame design the unit will need before the order is even placed.
Diego's problem was not bad equipment — it was temperature not matched to product. Losses occurred on three levels at once:
| Category | Recommended zone | Relative humidity | Notes |
|---|---|---|---|
| Produce (leafy, berries) | 0 ~ +4°C | 85%–95% | High humidity prevents wilting |
| Fresh meat (short-term) | 0 ~ +2°C | 85%–90% | Chilled retail |
| Frozen meat, poultry | −18°C | 90%–95% | Standard frozen |
| Seafood (shrimp, fish) | −18 ~ −25°C | 90%–95% | Depends on storage period |
| Ice cream | −25 ~ −30°C | — | Prevents softening and ice crystals |
| Pharma / vaccines | +2 ~ +8°C | 45%–75% | Requires temperature logging and alarms |
For customers like Diego who handle both chilled and frozen goods, the most economical solution is a dual-zone container cold room. Inside one 40HQ shell, an insulated partition wall splits the space into two independent zones:
A flower exporter in Bogotá, Colombia, needed 2–4°C pre-cooling for cut flowers and −18°C storage for cold-chain consumables. We customized a dual-zone 40HQ: front zone chilled, rear zone frozen, with two independent refrigeration units. The customer reported that one unit met both needs, with site footprint and purchase cost clearly lower than buying two single-zone units.
A vaccine distributor near Pune, India, needed +2 to +8°C storage — far warmer than a freezer, yet far more demanding on control. The risk with vaccines is not spoilage from heat alone but freezing damage: many vaccines are destroyed if they drop below +2°C. We supplied a chiller zone with tight tolerance (±0.5°C), a heated door frame to prevent frost, and ICOLD logging with alarms, so any excursion is captured for the audit trail. The customer's earlier attempt — storing vaccines "to be safe" in a −18°C freezer — had frozen an entire batch and cost a full shipment.
A common thread runs through all three cases: the right temperature is not the coldest temperature, and for sensitive goods it must be held within a narrow band, not merely "cold." Pharma and dairy in particular fail more often from being too cold than too warm.
Not every customer needs two zones. A meat wholesaler in Ho Chi Minh City stores only frozen pork and poultry, all at −18°C. He initially considered a deep-freeze unit "for extra safety," but the calculation showed that −18°C was fully sufficient for his storage periods, and a deep-freeze box would have added roughly 15 kWh/day of needless consumption. We supplied a simple single-zone −18°C freezer with 120 mm insulation; his monthly power cost came in about 35% below what the over-specified option would have cost, with identical product quality.
Back to Diego. We re-planned his temperature zones:
On the follow-up visit, Diego's numbers were striking: total energy use dropped about 30% versus the original "all deep-freeze" setup, complaints on chilled shrimp fell to nearly zero, and quality scores for quick-frozen shrimp meat actually rose. His summary was apt: "It's not about colder — it's about more precise."
Combined with the ECO+EMM energy system (about 35% lower overall energy than the industry average) and ICOLD cold cloud platform multi-zone monitoring, a Flandcold container cold room protects product quality while keeping refrigeration energy at an optimum. For customers handling multiple categories, the dual-zone custom solution in particular delivers significant savings in both purchase and operating cost.
Flandcold is a source factory producing 10,000 container cold room units a year, holding 60+ refrigeration patents, and exporting through 3,600+ service points. We offer a full temperature-zone line and dual-zone customization, with the ECO+EMM energy system and ICOLD cold cloud platform as standard — helping you get "temperature," the most basic yet most critical factor, exactly right.
Temperature is only half of a zone's specification. The other half is relative humidity and airflow, and getting them wrong causes losses that people mistakenly blame on temperature:
This is why a well-specified zone names not just a setpoint but a tolerance band and a humidity range. Two container cold rooms set to −18°C can perform very differently if one has even airflow and the other has dead spots.
No. Over-cooling wastes 30%–40% in energy and damages chilled goods. If your product mix is uncertain, a dual-zone unit is more forgiving than a single deep-freeze box, because you can run one zone warm and one cold.
Not safely. A "compromise" of −8°C freezes chilled produce and is too warm for safe long-term frozen storage. Products with different requirements need separate zones or separate units.
For a 40HQ, a deep-freeze unit consumes about 3–4× the daily energy of a chiller — roughly 25–35 kWh/day versus 6–9 kWh/day. That gap, multiplied across a year, is why matching the zone to the product pays for itself quickly.
Usually less. A dual-zone shell shares one insulated envelope, one set of doors, and one footprint, so both the purchase price and the standing heat load are lower than two separate units. The only case where two units win is when the two zones must be physically far apart.
Our engineering team responds within 24 hours with a temperature-zone plan matched to your categories and shipment rhythm.
Talk to a Flandcold engineer → Get a zone selection plan and quote
