Enormous temperature and humidity gradients occur in refrigerated and deep-freeze warehouses. The evaporators of the refrigeration systems are specifically installed where their thermodynamic efficiency is highest: below the ceiling, in the aisles between the rows of shelves. Warm, humid air rises, condenses on the cold surfaces of the evaporators and collects in the integrated condensate trays.
What sounds trivial at first presents a considerable technical challenge in practice. This is because the condensate produced must be drained reliably, frost-proof and hygienically - regardless of the building geometry, pipe lengths or heights. Sloping or downpipes are almost impossible to install here, which is why classic gravity drainage systems regularly reach their limits.
Limits of conventional drainage systems
In modern refrigerated and deep-freeze warehouses, downpipes are often impossible or can only be realised with great structural effort. Long downpipes lead through temperature zones with high frost potential and are susceptible to deposits, biofilms and blockages. Decentralised condensate pumps directly at the evaporators provide a remedy, but cause new problems:
- High number of individual components
- Difficult accessibility for maintenance and inspection
- Increased probability of failure
- Additional energy requirement
- Hygienic weak points due to standing water
Especially in highly automated logistics and storage environments, unplanned downtime of the refrigeration system is unacceptable. Condensate drainage is thus transformed from an auxiliary unit into a safety-relevant system component.
The physical approach: vacuum instead of gravity
Vacuum-assisted drainage systems take a fundamentally different approach. Instead of relying on slopes and free drains, the condensate is actively transported using negative pressure. The reduced ambient pressure in the pipework system has several decisive effects:
- Fewer components and interfaces
- Reduced maintenance and service costs
- Minimised risk of system downtimes
Drainage is thus decoupled from the structural constraints of the building - a decisive advantage in cold storage and deep-freeze warehouse construction.
Technical operating principle
The condensate is integrated into the vacuum pipework system directly at the condensate tray of the evaporator via an extraction unit. Extraction is demand-controlled and reliable - without open drains or standing water.
The condensate-air mixture is transported to a central vacuum station via the pipework system. There, the air and liquid are separated before the condensate is discharged into the sewerage system in a controlled and standardised manner.
All advantages at a glance
- Active suction prevents backflow and icing
- No free drainage, no open pipes
- Reduced susceptibility to faults even at extreme temperatures
- The reduced pressure lowers the freezing point of the condensate
- No trace heating required along long pipe sections
- Safe operation even in deep-freeze zones
- Long horizontal pipe runs without gradient
- Flexible positioning of the vaporiser
Condensate drainage is a critical, often underestimated component of modern refrigeration systems. Vacuum-assisted drainage offers a technically superior solution in refrigerated and deep-freeze warehouses with high demands on operational safety, hygiene and availability.
