System Design Complete Manual
From ammonia system conversion to new cold storage construction - complete coolant system design workflow guide. 4 major design topics, core parameter calculations, and design essentials quick reference.
• 4 Design Topics • 5 Parameter Calculations • 5 Design Essentials
Good System Design Is the Foundation of Stable Operation
Coolant system performance depends not only on the product itself but also on the rationality of system design. From ammonia system conversion to new cold storage, from pipe configuration to temperature differential control, every design detail can affect system performance and safety.
This manual systematically covers the key milestones and common issues in coolant system design based on real 2025 technical support cases.
System DesignKey Topics
Ammonia/Brine System Conversion
Customers unfamiliar with coolant systems need guidance on conversion process, milestones, and operation. Calculate coolant volume, heat exchange tube area, and pump circulation rate. Liquid transfer construction is safer. Pay attention to residual impurity cleaning.
Cold Storage Coolant System Design
Guide the calculation of heat exchange tube quantity, coolant volume, and defrost tank size. Recommend motorized valves on return lines to prevent backflow, with return positions at the bottom of the tank. Implement zoned temperature control.
Operating Temperature Differential Control
When system operating temperature differential is too small (1-1.5C), it is usually due to low end-load and excessive pump flow. Reduce pump frequency to lower flow rate and achieve the design temperature differential.
Freezing Point Safety Margin
Coolant freezing point selected too close to operating temperature may cause freezing from ambient fluctuations. Remind customer to drain water completely before filling. Freezing point should be 10-15C below minimum operating temperature. LM-430 and other economical antifreeze products require special attention.
System DesignReal Cases
Jinsheng Grain & Oil · Linyi
Cooling difficulties after adding enhancer; foam in tank
Possible component precipitation causing foam affecting heat exchange. Remove foam; may need defoamer; stop and circulate 24h then observe
- · Zhejiang
System operating temperature difference too small (1-1.5°C)
Low end-load, high pump flow. Recommended reducing pump frequency to lower flow
- · Zhejiang
LM-4 pressurization; system pressure near critical point
Recommended increasing nitrogen pressurization from 50kPa to 80kPa to prevent high-point flash vaporization
China Aerospace · Huanghua
Heat exchanger failed twice within 1 year/4 months after replacement
Found water tank return spray entraining large amounts of oxygen causing corrosion. Short-term: seal; long-term: replace with LM-4 (-15°C operation)
CoreParameter Calculations
| Design Parameter | Calculation Basis | Notes |
|---|---|---|
| Coolant volume | System pipe volume + tank volume x fill rate | Recommend purchasing 5-10% extra to prevent shortage |
| Heat exchange tube area | Based on cooling load, temp differential, and coolant thermal conductivity | Consider frost and fouling factors |
| Pump circulation rate | Based on heat exchange and temp differential: Q = P/(c x dT) | Consider viscosity impact on actual flow |
| Expansion tank volume | Total coolant x expansion coefficient x temp differential | Cannot be omitted - prevents thermal expansion overpressure |
| Freezing point selection | Minimum operating temp - 10-15C safety margin | Over-pursuing low freezing point increases viscosity and cost |
Return line design: Install motorized valves to prevent backflow; position return at tank bottom to reduce agitation and oxygen entrainment.
End branches: Add air vent valves to prevent air locks affecting circulation.
Zoned temperature control: Multi-temperature cold storage should be designed with zones to avoid uneven temperature control.
Sealing design: Seal tank or use nitrogen blanketing to prevent oxygen ingress and corrosion.
Safety devices: Expansion tank + safety valve + pressure gauge - all three are indispensable.
DesignFAQ
Cause: Customer unfamiliar with coolant systems, unsure how to convert
Solution: Explain specific procedures, conversion milestones, and system operation. Calculate coolant quantity, heat exchange coil area, pump circulation. Provide conversion plan and precautions. Empty-tank construction is safer
Cause: Customer designing coolant system for first time, lacks design experience
Solution: Guide calculation of heat exchange coil quantity, coolant volume, defrost water tank size. Recommend electric valve on return line to prevent backflow; return position at tank bottom. Zone temperature control
Cause: Low end-load, excessive pump flow
Solution: Reduce pump frequency to lower flow rate, achieving design temperature difference
Cause: Coolant freezing point selection too marginal; environmental fluctuations may cause freezing
Solution: Remind customer to drain water completely during filling, ensure adequate freezing point safety margin. Recommend freezing point 10-15°C below minimum operating temperature
Related Topics
Selection decisions before system design
System pressure safety design essentials
Anti-corrosion strategies at the design stage
Preferred coolant for cold storage systems
Post time: Aug-27-2026