LAUDA Loop L 250, circulation bath, Peltier technology, 250 W, L000580

Thermoelectric solid-state thermodynamics (Peltier effect)

The precise isochoric temperature control of sensitive external instruments in optical analysis (such as refractometers or polarimetres) requires a constant heat sink without oscillating refrigerant cycles. The LAUDA Loop L 250 completely eliminates the need for a conventional compression chiller and operates on the basis of Advanced Peltier Technology. Thermodynamic energy transfer takes place via thermoelectric semiconductor junctions which, when a direct current is applied, extract thermal energy from the fluid temperature-control medium (cooling capacity of 250 W at 20 °C). Thanks to microprocessor-controlled polarity reversal, exactly the same Peltier elements function as heating units (heating capacity 400 W). This reversible electron flow completely eliminates the thermodynamic dead band of conventional compressors around the ambient temperature zero point and enables metrological temperature stability of ± 0.1 K within the operating range of 4 °C to 80 °C.

Vibration elimination and fluid-mechanical kinematics

A fundamental analytical advantage of the compressor-free architecture is the absolute absence of mechanical vibration. As there are no reciprocating piston compressors or expanding F-gases (refrigerants) to oscillate, no macromechanical vibrations are induced in the temperature control circuit or the housing. This is absolutely essential when the system is physically operated in the vicinity of highly sensitive laser spectrometers or scanning electron microscopes. The internal fluid-mechanical kinematics are achieved by a high-performance circulation pump, which delivers a delivery pressure of 0.8 bar and a maximum hydrodynamic flow rate of 3 l/min into the closed external circuit. To minimise the time required for set-up when switching between different consumers, the system is fitted as standard with Quick C. 1/4" quick-release couplings, which guarantee a drip-free and hermetic disconnection of the pipework network.

System cybernetics and global energy self-sufficiency

The electronic interface is controlled via an extremely high-contrast graphical OLED display and an intuitive 3-button soft-key architecture, which modulates the PID control loop without latency. A serial RS-232 interface is integrated for seamless GLP-compliant data logging in automated laboratory environments. To counteract infrastructural anomalies in various global power grids, the Loop L 250 is equipped with a wide-range power supply (100 to 240 V, 50/60 Hz). This physically safeguards the continuous kinetics and thermodynamics of the assay, even in the event of fluctuating mains voltages.

Technical details

Thermodynamics & Peltier technology

• Operating temperature range: 4 °C to 80 °C
• Cooling capacity (at 20 °C): 250 W
• Cooling capacity (at 10 °C): 130 W
• Heating capacity (maximum): 400 W
• Temperature stability (in accordance with DIN 12876): ± 0.1 K
• Cooling technology: Thermoelectric (Peltier elements, compressor-free, no refrigerant)

Metrology & Control Engineering

• Control: PID microprocessor
• Cybernetic interface: Graphical OLED display
• Operating concept: 3-button soft-key navigation
• Data interface: RS-232 (serial)

Fluid mechanics & pump kinematics

• Delivery pressure (maximum): 0.8 bar
• Flow rate (maximum): 3 l/min
• Filling volume (maximum): 320 ml
• Hydraulic connection (in/out): Quick C quick-connect coupling, 1/4"
• Permitted temperature-control media: Non-flammable fluids (water, water-glycol mixtures)

System infrastructure & dimensions

• System dimensions (W x D x H): 261 x 368 x 312 mm
• Machine weight: 11.7 kg
• Cooling method: Air-cooled
• Noise emission: 57 dB(A)
• Protection rating (to DIN EN 60529): IP 21 (Class I / NFL)

Electrical & Energy Management

• Mains supply: 100 – 240 V (wide-range input)
• Frequency: 50/60 Hz
• Power consumption (maximum): 400 W

Contents of delivery

• 1 x LAUDA Loop L 250 circulation bath
• 1 x ITU mains cable (with CEE7/7 earth-equipped plug)
• 2 x quick-connect couplings (Quick C. 1/4")

Important note: Thermally insulated pump hoses to prevent thermodynamic losses, an external temperature-control medium (such as demineralised water or water-glycol mixtures) and specific thread adaptors for peripheral devices are essential for process operation and are not included in the scope of delivery.

Customised requirements & accessories

The Loop L 250 is a purely physical heat sink and heat source. To transfer the generated thermal power of 250 W isochorically to the external reactor or analytical instrument without dissipating energy into the laboratory atmosphere, it is essential to use highly insulated silicone or polymer hoses. At operating temperatures close to 4 °C, the use of uninsulated material will inevitably lead to condensation forming on the outer surface. When purchasing the tubing, please ensure it is fully compatible with the supplied 1/4" quick-connect couplings. Please contact our procurement service at any time for the fluid-dynamic and thermodynamic configuration of your circuit.