- Client: European Spallation Source (ESS), Sweden
- Cooling Power: 0.8 kW (800 W)
- Temperature Range: Holding at 30°C ±0.5°C
- Conductivity: ≤ 0.5 µS/cm
- Dissolved Oxygen: <= 50 ppb
- System Capacity: Multiple inlet/outlets; portable skid
- Interesting System features: Standalone operation and interface to ESS master control; Siemens S7‑1500 PLC
ESS required a portable, four‑circuit DI water plant to support a cryogenic module test stand, which required very tight limits on water purity and thermal stability. GRE designed and delivered a full stainless‑steel (to wetted parts) system, engineered to operate either as a self‑contained unit or integrated with the site’s master control, using a Siemens S7‑1500 PLC with MODBUS and accessories for control, communication and diagnostics. Materials were selected for ultra‑pure water service: fully welded 316L stainless steel tube for wetted components/pipework (UHMWPE and/or EPDM where elastomers were unavoidable). All, stainless components were chemically cleaned and passivated post fabrication, to optimize the chromium oxide layer and reduce ionic leaching in low‑conductivity water.
To maintain ≤0.5 µS/cm in a recirculating loop, the conditioning sub-system includes mixed‑bed ion exchange (polishing) and 0.2 μm final filtration with UV for bioburden control. A compact membrane degasser provided oxygen reduction to tens of parts‑per‑billion, improving corrosion control even more. The thermal subsystem uses a precision heater together with a proportional control valve on a plate heat exchanger via GRE designed cascade PID loop, which maintains the setpoint under transient loads. The software also incorporated interlocks on flow, pressure, conductivity and temperature, and provided a recipe‑based operation for each circuit.
Given ESS’s radiological environment, seals and instrumentation were specified for radiation tolerance and decontamination compatibility. The portable skid also utilizes anti‑vibration mounts and quick‑release hygienic connectors to accelerate setup.
The result was a stable, low‑noise cooling platform that protects sensitive electronic equipment, while offering operators intuitive control, event logging and remote diagnostics.