How to design the process flow
The cooling method of different scales and data centers determines the specific approach to water treatment, which is generally divided into two scenarios: traditional air-cooled/water-cooled and emerging liquid-cooled.
- Traditional Data Centers (Air-cooled/Water-cooled)
- Small and Medium-sized: Typically follow the route of "municipal water supply → multi-media filtration → softening → circulation system → automatic dosing". The focus is on reducing hardness to prevent scaling in the cooling tower, achieving a water savings rate of 30%–40%.
- Large/Ultra-large: Higher requirements necessitate adding pretreatment upfront and dual-membrane reuse downstream. The process becomes "municipal water supply → pretreatment → softening → RO makeup water → circulation system → dual-membrane reuse", achieving a water reuse rate of 70%–85% and increasing the concentration ratio to 8–12 times.
- Core Equipment: Common equipment includes raw water tanks, multi-media filters (quartz sand), activated carbon filters, softeners, high-pressure pumps, and reverse osmosis units, ultimately producing purified water for supply points.
- AI Computing/Liquid-cooled Data Centers
- Ultra-high Water Quality Requirements: Since servers are directly immersed in coolant or use cold plates, the water quality must be ultra-pure, with resistivity ≥15MΩ·cm, and low dissolved oxygen and low chloride ions to prevent corrosion.
- Process Upgrade: Typically adopt a deep treatment process of "municipal water supply → two-stage RO → EDI → polishing mixed bed → ultra-pure water", achieving a water utilization rate of over 95%.
- Zero Chemical Trend: For environmental protection, electrochemical descaling or pulsed electromagnetic wave devices are now popular, achieving chemical-free operation throughout the process, softening water quality while reducing wastewater discharge.
What are the requirements for water quality standards?
Water treatment cannot be done arbitrarily; it must comply with national and industry mandatory indicators, otherwise, it will not pass acceptance checks.
- Key Reference Standards
- Group Standard: "Technical Guidelines for Water Use in Data Centers" (T/BIE 001—2017) is commonly used in the industry, specifying full lifecycle management from new construction to operation and maintenance.
- National Water Quality Standard: Makeup water for circulating chilled water systems must comply with GB/T 29044-2012, and wastewater discharge from air conditioning systems must meet the Grade III discharge standard of GB 18918.
- Water Conservation Evaluation: Standards such as DB11/T 1764.11 in Beijing specify clear scoring items for air conditioning cooling water circulation rate (≥98.5%) and concentration ratio (≥5).Encyclopedia
- Core Monitoring Indicators
- Hardness Control: The hardness of softened water output is typically required to be ≤0.03 mmol/L to prevent scaling in heat exchangers and ensure heat dissipation.
- WUE Indicator: Water Usage Effectiveness, with advanced solutions requiring WUE ≤ 1.0 L/kWh(IT); the lower the value, the more water-efficient.
- Corrosion and Bacteria Prevention: Chloride ion levels and microbial growth must be controlled to prevent biofouling from clogging pipes, with UV disinfection used when necessary.