Blast freezer and chilled store on R290 plant for a South-West seafood processor

The brief

A seafood processor in South West England landed fresh catch, graded and packed it, and froze a proportion for wider distribution. The operation depended on two things happening reliably: fresh fish held cold and clean from landing to pack, and a fast freeze that protected grade and value on the portion sold frozen. The existing arrangement was struggling on both fronts. An old chilled room ran warm on busy landing days, and a tired blast cabinet could not freeze fast enough to keep up with throughput, so fish was sitting too long before the core came down.

The processor’s technical manager had two non-negotiables. First, the freeze had to be fast and documented, because slow freezing grows large ice crystals that damage texture and cost grade, and a major customer audit required validated pull-down records. Second, the processor could not afford a total loss of cold capacity: a plant failure that spoiled a day’s landing would be a serious financial hit. The refrigerant also had to be a sensible long-term choice given the tightening F-gas rules.

What we installed

We installed a 600kg-per-cycle blast freezer running -35°C air-off, sized on the processor’s batch weights and the pull-down time needed to drive the fish core down fast through the ice-formation zone. High-velocity evaporator fans were arranged to sweep air evenly across every tray position so the whole load froze at the same rate, with no slow spots that would fail the process.

Alongside it we built a 40-pallet chilled store held at +2°C on a hygienic PIR insulated envelope with food-contact panel finishes, sized to hold fresh catch reliably even on peak landing days, with strip curtains and a self-closing door to cut infiltration on a busy pick face.

Both were built on R290 (propane) packaged plant. R290 sits outside the HFC phase-down, is efficient, and suited the packaged format of this installation. Because the processor could not risk losing all cold capacity, we specified a dual-circuit design so a single circuit failure would not take out the whole system, protecting a day’s landing while the fault was repaired. The blast freezer was commissioned with calibrated core-temperature probes and time-temperature logging on every cycle.

The numbers

Combined refrigeration electricity across the old chilled room and blast cabinet had been running at around £74,000 a year. The new R290 plant, correctly sized and paired with the tighter chilled envelope and better door discipline, cut that by around £13,000 a year, a reduction of roughly 18 per cent, before any solar offset. The saving came from efficient plant running at the right duty rather than an undersized system labouring flat out, and from cutting infiltration on the chilled store.

The plant qualified as plant and machinery for capital allowances, so the processor claimed first-year relief on the qualifying capex. Simple payback against the running-cost saving alone landed at around six years, with the stronger case being the protected grade on the frozen product and the removal of the audit risk.

Resilience and audit outcome

The blast freezer’s pull-down was validated against the processor’s specified freezing process, with recorded core temperatures on every cycle, so the HACCP-critical freeze step was documented and auditable. The chilled store was temperature-mapped with calibrated probes to confirm it held +2°C evenly, and continuous monitoring with alarms flagged any drift before stock was at risk. Together these gave the processor the validated records its customer audit required, which the old plant could not provide.

The dual-circuit design changed the risk on landing days. Where a single-circuit failure on the old system would have threatened a whole day’s catch, the redundant design now holds cold capacity while a fault is dealt with, protecting the stock the business runs on.

Cutting the bill further with solar

With efficient plant in place, the remaining lever on the refrigeration bill was offsetting the load. The chilled store and holding refrigeration run around the clock, so the demand is steady and well matched to on-site solar, which feeds generation straight into a constant load with high self-consumption. We flagged the offset opportunity to the processor and referred the array sizing to our sister service for solar on seafood and cold storage sites, which models the array against half-hourly load rather than a rule of thumb.

The takeaway

Correctly sized R290 plant, a tighter chilled envelope and a validated blast freeze cut a seafood processor’s refrigeration bill by around £13,000 a year while protecting product grade and passing a customer audit that the old plant would have failed. It shows the same discipline at smaller scale as our larger cold-store projects: size the duty to the real product and throughput, choose a refrigerant with a future, design in redundancy against the losses a failure would cause, and document the process so it stands up to audit. To scope a comparable installation, see our blast freezer guide and request a quote.