COLD STORES
The hidden cost of open doors in cold stores
Cold storage operators are under mounting pressure to cut energy waste and boost effi ciency. Tony Fleming of JS Air Curtains explains why something as simple as an open door can quietly drain performance, and what operators can do about it.
"This is why air curtain performance is increasingly viewed as an engineering consideration rather than simply a product
choice. Correct positioning, airfl ow
balancing, and commissioning all play a major role in determining eff ectiveness."
same time, cold stores are handling higher volumes of traffi c as food logistics, pharmaceutical distribution, and rapid fulfi lment operations continue to expand. For many facilities, maintaining low temperatures is no longer the biggest challenge. The real challenge is maintaining them effi ciently, consistently, and safely while supporting fast- moving operations. That is placing greater focus on one of the most persistent - and often underestimated - causes of energy loss in cold stores: open doorways. Every time a cold store door opens, warm external air enters the space while colder internal air escapes. Refrigeration systems must then work harder to restore the required temperature, increasing energy consumption and placing additional strain on plant equipment. Over time, the impact becomes signifi cant. Temperature
A
fl uctuations can aff ect product quality, condensation can create safety risks, and repeated thermal loading can increase maintenance requirements and reduce equipment lifespan. In busy facilities where doors are opening continuously
throughout the day, these losses can quickly add up. That is why airfl ow management is becoming a much bigger conversation across the refrigeration sector.
Why doorways matter Doorways are one of the weakest points in the thermal envelope of any cold store.
As soon as a door opens, warmer ambient air naturally
moves towards the colder environment while denser cold air escapes at a lower level. Moisture enters the space, refrigeration load increases, and maintaining stable temperatures becomes more diffi cult. In high-traffi c facilities, particularly distribution centres and food production environments, keeping doors closed is not practical. Forklifts, pallet trucks, and staff are moving constantly between temperature zones, often around the clock. The challenge for operators is therefore not eliminating
22 July 2026 •
www.acr-news.com
cross the sector, businesses are balancing rising energy costs, tighter sustainability targets, changing legislation, and growing operational demand. At the
thermal exchange, but reducing it enough to improve overall environmental control and system effi ciency. Research into refrigerated chamber performance has shown that although thermal transfer cannot be completely prevented because of turbulence and air mixing, it can be signifi cantly reduced through eff ective airfl ow management.
Understanding how air curtains work This is where air curtains are becoming increasingly important in cold store applications. An air curtain works by creating a controlled stream of air
across an open doorway, forming an aerodynamic barrier between two environments with diff erent temperatures. In cold storage applications, the aim is to reduce the transfer of warm air into the refrigerated space while limiting the escape of cold air outwards. By reducing that exchange of air, refrigeration systems do not need to work as hard to recover temperatures after door openings. While the concept sounds straightforward, the airfl ow behaviour itself is surprisingly complex. As the air stream travels towards the fl oor, turbulence and mixing occur on both sides of the jet. Some air is naturally entrained into the airfl ow, meaning thermal transfer cannot be eliminated entirely. However, when correctly designed and installed, an air curtain can reduce energy loss by more than 65%, compared with an unprotected opening. Research using computational fl uid dynamics (CFD) modelling has shown that airfl ow velocity and discharge angle are among the most critical factors aff ecting performance. If airfl ow velocity is too low, the airstream can collapse and allow warm air to penetrate the cold store. If velocity is too high, turbulence increases and mixing between warm and cold air becomes more severe.
Positioning also matters. Small changes in discharge angle can infl uence how eff ectively the airfl ow separates environments and counters the natural movement of warm and cold air around the doorway. This is why air curtain performance is increasingly
viewed as an engineering consideration rather than simply a product choice. Correct positioning, airfl ow balancing,
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