PELTIER EFFECT AND REFRIGERATION IN REFRIGERATED CENTRIFUGE

Peltier Effect named after Jean Charles Athanase Peltier, the physicist who discovered the effect in 1834. He found when electric current is passed through a circuit consisting of two different conductors, a cooling effect is observed in one junction whereas another junction experiences a rise in temperature. This change in temperatures at the junctions is called the Peltier effect. The heating or cooling effect observed at a junction can be reversed by changing the direction of the current flow. The phenomenon behind the Peltier effect is used in the function of thermoelectric heat pumps and thermoelectric cooling devices.

 Refrigerated centrifuge is widely used in chemistry, biology, and biochemistry for isolating and separating suspensions.  Many samples, such as live cells, tissues and proteins, are temperature sensitive. Human tissue samples must be kept at the mammalian body temperature of 37°C. Temperature changes by as little as 6°C can significantly impact cell health and render the centrifuge process worthless.

 To ensure precise temperature control for laboratory and medical centrifuge applications use two types of cooling systems:

Compressor-based systems

Thermoelectric(Peltier)coolers 

Uses traditional (R134a and R404A) & natural refrigerants [R744 (carbon dioxide), R717 (ammonia), R290 (propane), R600a (isobutene), and R1270 (propylene)], government restrictions, hazardous

More efficient

Cost effective

Reliable

Refrigerant free

cooling below ambient temperatures, fast ramp rates, precise temperature control, accurate to within ±0.01˚C under steady-state conditions, and low noise.

 

 Ultracentrifuges and high-speed centrifuges typically require a thermoelectric assembly cooling solution. Depending on the type of sample, a centrifuge tub typically must maintain a precise temperature between 0°C and 40°C. A temperature controller takes feedback from a temperature sensor to vary the output of the power supply to control the temperature inside a centrifuge tub. Peltier cooling assemblies is ideal for laboratory centrifuge applications.

 

 

Dr.Ashutosh Rawat

HOD Microbiology