The Great Wall DL249 Integrated Circulating Chiller

Overview

The Great Wall DL249 Integrated Circulating Chiller is a precision-engineered thermal management system designed for continuous, stable temperature control of external laboratory equipment—including rotary evaporators, spectrophotometers, laser sources, vacuum pumps, and analytical instrumentation requiring active cooling or precise thermal regulation. Operating on the vapor-compression refrigeration cycle with R404A refrigerant, the unit delivers consistent cooling performance across a wide operational range of −20 °C to +40 °C. Its integrated architecture eliminates the need for external condenser units or auxiliary water connections, enabling rapid deployment in standard laboratory environments with ambient conditions between 5 °C and 35 °C and relative humidity ≤70%. The chiller employs a high-efficiency hermetic compressor, copper-aluminum finned condenser, and capillary tube expansion device—optimized for reliability under sustained load. Temperature stability of ±0.5 °C is maintained via real-time feedback from a calibrated Pt100 sensor and proportional-integral (PI) digital temperature controller, ensuring reproducible thermal conditions critical for method validation and process consistency.

Key Features

• Integrated design with self-contained refrigeration circuit, reservoir, circulation pump, and control electronics in a single compact chassis (300 × 480 × 630 mm).
• Stainless steel (06Cr19Ni10 / AISI 304) reservoir resistant to corrosion from common heat transfer fluids including water, water-glycol mixtures, and silicone oils.
• High-flow, low-pulsation centrifugal circulation pump delivering up to 23 L/min at 1.2 bar maximum pressure—compatible with standard G1/2 BSP fittings and silicone tubing (Φ13 × Φ9 mm).
• Digital LED display with intuitive interface for setpoint entry, real-time temperature readout, and status indication of operational mode and fault conditions.
• Comprehensive safety architecture including compressor time-delay startup, overheat cutoff, overcurrent protection, and high-pressure switch—designed to meet IEC 61010-1 requirements for laboratory electrical equipment.
• Energy-efficient operation with 1000 W rated input power and scalable cooling capacity: 1300 W @ 20 °C ambient, 1150 W @ 10 °C, and 900 W @ 0 °C ambient—enabling adaptability across seasonal lab environments.

Sample Compatibility & Compliance

The DL249 is compatible with a broad spectrum of heat-transfer media, including deionized water, 30–50% aqueous ethylene glycol solutions, and low-viscosity silicone oils (up to 50 cSt), supporting applications requiring sub-zero temperatures without freezing risk. Its reservoir geometry and internal baffle design minimize thermal stratification and promote uniform fluid mixing. The unit complies with electromagnetic compatibility (EMC) standards per IEC 61326-1 and meets basic safety requirements under IEC 61010-1 Edition 3 for electrical equipment used in measurement, control, and laboratory use. While not certified for medical or pharmaceutical cleanroom environments, its construction and control logic support integration into GLP-compliant workflows when paired with documented calibration and maintenance procedures. It does not incorporate FDA 21 CFR Part 11–compliant audit trail functionality; however, temperature setpoints and operational status can be manually logged as part of routine instrument qualification protocols.

Software & Data Management

The DL249 operates via embedded firmware with no external software dependency. All configuration and monitoring occur through the front-panel digital interface. No USB, RS-232, or Ethernet connectivity is provided; therefore, remote data logging or SCADA integration requires third-party analog signal acquisition (e.g., via 0–10 V or 4–20 mA output modules, if externally interfaced). For laboratories requiring electronic records, users may integrate the chiller into broader environmental monitoring systems using optional analog output adapters—subject to site-specific validation. Firmware updates are not field-upgradable; service-level recalibration and diagnostic support are available directly through The Great Wall’s authorized technical centers in mainland China.

Applications

• Temperature stabilization of rotary evaporator condensers during solvent recovery (especially low-boiling-point solvents such as diethyl ether or pentane).
• Cooling of high-power laser diodes and optical detectors where thermal drift compromises signal-to-noise ratio.
• Thermal conditioning of HPLC column ovens and detector cells to ensure retention time reproducibility.
• Heat dissipation for vacuum pump motor housings operating under extended duty cycles.
• Controlled cooling of reaction vessels in small-scale synthesis setups where exothermicity must be actively managed.
• Support of calorimetric measurements requiring baseline thermal equilibrium prior to sample introduction.

FAQ

Can the DL249 achieve +40 °C output temperature in all ambient conditions?
No. The +40 °C upper limit is achievable only when ambient temperature exceeds 15 °C and the unit operates in pump-only mode (refrigeration circuit disengaged) with an empty or lightly loaded external loop.
Is the reservoir volume sufficient for large-volume external systems?
The 9 L reservoir supports typical laboratory loops with total fluid volumes under 25 L. For larger systems (>30 L), external expansion tanks may be required to maintain stable head pressure and avoid cavitation.
What maintenance intervals are recommended?
Compressor oil and refrigerant integrity should be verified annually; condenser coils require biannual cleaning with compressed air or soft brush; reservoir fluid should be replaced every 6–12 months depending on heat-transfer medium and usage frequency.
Does the unit support dual-temperature zones or independent inlet/outlet temperature control?
No. The DL249 regulates a single circulating loop with one setpoint; it does not provide multi-zone or differential temperature control capabilities.
Can R404A be replaced with a lower-GWP alternative refrigerant?
R404A is sealed within the factory-charged refrigeration circuit. Substitution is not supported—neither mechanically nor under warranty—and violates refrigerant handling regulations in most jurisdictions (e.g., EU F-Gas Regulation, EPA SNAP).