I. Critical Accessories for Low-Temperature Chillers

1. Flow Switch

• Function: Monitors pipeline fluid flow for cut-off protection. Automatically opens/closes circuits when flow reaches preset values.

• Application: Ensures adequate coolant flow to prevent dry-running damage.

2. Pressure Controller

• Function: Safeguards system pressure ranges (low/high pressure limits). Triggers circuit interruption at preset thresholds.

• Example: Prevents compressor overload due to abnormal pressure fluctuations.

3. Differential Pressure Controller

• Function: Controls pressure differences (e.g., across filters). Activates at predefined ΔP values.

• Use Case: Alerts for clogged filters in water-cooled systems.

4. Temperature Controller

• Function: Regulates/PROTECTS via temperature thresholds (e.g., tank temperature for on/off control, anti-freeze protection).

• Industry Practice: Integral for automated start-stop cycles and frost prevention.

5. Solenoid Valve

• Function: Cuts refrigerant flow during compressor shutdown to prevent liquid slugging.

• Note: Essential for large systems (>10HP) to avoid mechanical failure.

II. Three Refrigeration Methods

1. Vapor Compression Refrigeration (Most Common for Chillers)

• Step 1 Compression: Converts low-T/P gas → High-T/P gas.

• Step 2 Condensation: Cools high-T/P gas → High-P liquid (heat rejection).

• Step 3 Expansion/Evaporation: High-P liquid → Low-P gas (absorbs heat → cooling effect).

2. Gas Expansion Refrigeration (Used in Cryogenics)

• Method A: Expansion Turbine

• High-P gas expands with work output → Large temp drop → High cooling capacity.

• Pros: Efficient. Cons: Complex machinery.

• Method B: Throttling Valve

• Gas expands without work output → Small temp drop → Limited cooling.

• Pros: Simple/adjustable. Cons: Lower efficiency.

3. Thermoelectric Cooling (Niche Applications)

• Principle: Peltier effect (electric current → temperature gradient).

• Use: Small-scale precision cooling (e.g., medical devices).

Key Notes for Assembly & Operation

• Safety: Always calibrate controllers (pressure/temp) per OEM specs.

• Efficiency: Pair vapor compression with plate heat exchangers for 15–20% energy savings.

• Maintenance: Clean strainers/condensers quarterly to avoid 10–30% performance loss.

Example: A pharmaceutical plant reduced downtime by 40% after installing differential pressure controllers for real-time filter monitoring.

For custom configurations (e.g., ultra-low -40°C systems), consult engineering teams.