| 1 | Test the Incoming Water | Feed-water temperature, pH, total dissolved solids (TDS), hardness, alkalinity, chloride, iron, and suspended solids. Baseline assessment | Water chemistry affects heat-transfer surfaces, corrosion risk, scaling tendency, pretreatment requirements, and the expected service life of the chiller. | Obtain a recent laboratory water analysis and compare the results with the chiller manufacturer’s allowable water-quality limits before selecting materials or capacity. |
| 2 | Match the Chiller to the RO Stage | Permeate, concentrate, raw feed water, or product-water service; typical RO permeate TDS is often below feed-water TDS, while concentrate has a higher salt concentration. Define service water | The same chiller may experience very different conductivity, chloride concentration, fouling potential, and corrosion conditions depending on its location in the RO process. | Specify the exact water stream, expected minimum and maximum TDS, chloride level, temperature, flow rate, and operating hours in the purchase requirements. |
| 3 | Check Material Compatibility | Wetted parts may include stainless steel, plastics, elastomers, copper alloys, titanium, or protective coatings. Confirm compatibility with pH, chloride, cleaning chemicals, and temperature. Corrosion control | Chlorides can promote localized corrosion in susceptible stainless steels, while acidic or alkaline cleaning solutions may damage unsuitable metals, seals, or coatings. | Request a wetted-material list and chemical-compatibility statement. Select corrosion-resistant materials for high-chloride or chemically aggressive water and verify gasket compatibility. |
| 4 | Size Cooling Capacity Correctly | Cooling duty depends on water flow, specific heat, and the required temperature drop. For water: Cooling load ≈ 4.186 × flow (L/s) × temperature drop (°C) kW Capacity calculation | An undersized chiller cannot maintain the target temperature during peak demand. Oversizing may increase capital cost, cycling, and control instability. | Use the maximum design flow and worst-case inlet temperature. Include a practical design margin, commonly around 10–15%, after confirming site conditions and control requirements. |
| 5 | Verify Temperature and Pressure Limits | Confirm inlet and outlet temperature range, design pressure, pressure drop, ambient temperature, and minimum flow required by the heat exchanger and refrigeration circuit. Operating envelope | Exceeding temperature or pressure limits can damage components, reduce cooling performance, cause nuisance alarms, or create unsafe operating conditions. | Compare the chiller datasheet with actual RO operating conditions, including pump shutoff pressure, seasonal ambient temperature, startup conditions, and possible flow fluctuations. |
| 6 | Control Scaling, Fouling, and Biofilm | Review hardness, alkalinity, silica, suspended solids, turbidity, residual disinfectant, and biological-control practices. A commonly used drinking-water turbidity target is below 1 NTU, subject to local requirements. Heat-transfer protection | Scale and fouling reduce heat-transfer efficiency, increase pressure drop, restrict flow passages, and can raise energy consumption and maintenance frequency. | Use appropriate pretreatment, filtration, antiscalant or softening where required, and a documented cleaning schedule. Install strainers or filters when permitted by the process design. |
| 7 | Plan Sanitation and Maintenance | Check drainability, access for inspection, clean-in-place requirements, service clearances, replacement parts, leak detection, temperature monitoring, and alarm functions. Lifecycle reliability | RO systems may operate continuously, so poor access or unsuitable internal geometry can make cleaning difficult and increase the risk of contamination, downtime, or performance loss. | Prefer hygienic, fully drainable flow paths where product water is involved. Define inspection intervals, water-quality checks, cleaning chemicals, calibration tasks, and spare-parts requirements before commissioning. |