This simplified model captures the main relationship only. Boundary conditions, losses, nonlinear effects, and code-specific corrections still need separate checks.
How to read it
Use the main plot to read the controlling trend, including break points that a single result card can hide.
Use the sensitivity view to find input combinations where margin collapses quickly.
For early design, focus on which input controls margin before trusting the absolute value.
Learn Desalination Energy Recovery by dialogue
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When reading Desalination Energy Recovery, where should I look first? Moving Pump pressure changes both the plots and the result cards.
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Start with SEC, but do not treat the number as the whole answer. Use Recovery and SEC curve to confirm the assumed state, then read Pump and recovered energy for the distribution or trend. Use the main plot to read the controlling trend, including break points that a single result card can hide.
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I can see why Pump pressure changes SEC. How should I judge the influence of Recovery R?
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Move Recovery R in small steps and watch Feed flow. That reveals which term is controlling the result. This simplified model captures the main relationship only. Boundary conditions, losses, nonlinear effects, and code-specific corrections still need separate checks. A single operating point is not enough; sweep the realistic scatter range.
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What is Pressure-ERD SEC map for? It feels like the ordinary curve already tells the story.
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Pressure-ERD SEC map is for finding boundaries where the condition becomes risky or margin collapses quickly. Use the sensitivity view to find input combinations where margin collapses quickly. In First-pass comparison of design options before review, the important question is often what happens after a small change, not only the nominal value.
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So if SEC is within the target, can I accept the condition?
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Treat this as a first-pass review. It helps with Narrowing controlling factors and worst-side conditions before detailed analysis and Teaching or explaining the equation, numbers, and visualization under the same inputs, but final decisions still need standards, measured data, detailed analysis, and vendor limits. For early design, focus on which input controls margin before trusting the absolute value.
Practical use
First-pass comparison of design options before review.
Narrowing controlling factors and worst-side conditions before detailed analysis.
Teaching or explaining the equation, numbers, and visualization under the same inputs.
FAQ
Start with SEC and Feed flow. Then use Recovery and SEC curve to confirm the assumed state and Pump and recovered energy to read distribution or bias. Use the main plot to read the controlling trend, including break points that a single result card can hide
Move Pump pressure alone, then move Recovery R by a comparable amount and compare the change in SEC. Pressure-ERD SEC map shows combinations where margin or performance changes quickly.
Use it for First-pass comparison of design options before review. Instead of trusting a single point, widen the input range and check whether SEC keeps enough margin before moving to detailed analysis.
This simplified model captures the main relationship only. Boundary conditions, losses, nonlinear effects, and code-specific corrections still need separate checks. Final decisions still require standards, measured data, detailed analysis, and vendor limits.
How to Use
Enter osmotic pressure (bar) – typically 25–30 bar for seawater, 5–15 bar for brackish water.
Set recovery ratio (%) – standard RO plants operate 35–50%; higher ratios increase energy demand and concentrate disposal volume.
Input ERD efficiency (%) – modern turbochargers and Pelton wheels achieve 80–95% hydraulic-to-mechanical conversion.
Specify pump mechanical efficiency (%) – centrifugal RO pumps typically 75–88% at nominal flow.
Read SEC (specific energy consumption in kWh/m³), feed/brine flow rates, and annual energy savings from pressure recovery.
Worked Example
Seawater desalination plant: feed pressure 60 bar, recovery 42%, ERD (pressure exchanger) 87% efficient, pump 82% mechanical efficiency. High-pressure feed ~1200 m³/h drives RO membranes. Brine discharge at elevated pressure powers the ERD; recovered power reduces net SEC from 4.8 kWh/m³ to 3.2 kWh/m³. Annual freshwater output 176,000 m³ saves 563 MWh and €84,450 at €0.15/kWh. Neglecting ERD drops SEC to 5.1 kWh/m³, costing an extra €141,000 annually for equivalent throughput.
Practical Notes
Higher recovery (55%+) demands thicker, costlier membranes and fouling control; balance against feed/disposal logistics in coastal vs. inland sites.
Pressure exchangers (PX) and Pelton turbines suit different flow regimes; PX dominates <2000 m³/h, turbines scale to large plants, both require <5% maintenance burden.
Pump cavitation risk rises above 70 bar inlet; verify NPSHR and suction lift to avoid energy loss and hardware damage in high-salinity, warm feedwater.
ERD failure or bypass (fouled valve) cuts savings by 1.5–2.0 kWh/m³; monitor differential pressure and flow balance weekly to ensure ERD operation.