What are thermoelectric heat pumps?

Thermoelectric heat pumps perform the same cooling function as freon-based vapor compression or absorption refrigerators. In all such units, thermal energy is extracted from a region, thereby reducing its temperature, then rejected to a "heat sink" region of higher temperature. Vapor-cycle devices have moving mechanical parts and require a working fluid, while thermoelectric elements are totally solid state.

Melcor's solid state heat pumps use thermocouples made of high performance crystalline semiconductor material. Passing a current through the heat pump generates a temperature differential across the thermocouples, with maximum ratings of 70°C and higher.

Solid state heat pumps have been known since the discovery of the Peltier effect in 1834. The devices became practical only recently, however, with the development of semiconductor thermocouple materials. Melcor utilizes bismuth telluride, a quaternary alloy of bismuth, tellurium, selenium and antimony - doped and processed to yield oriented polycrystalline semiconductors with anisotropic thermoelectric properties. The couple, connected in series electrically and in parallel thermally, are integrated into modules. The modules are packaged between metallized ceramic plates to afford optimum electrical insulation and thermal conduction with high mechanical strength in compression. Typical Melcor modules contain from 3 to 127 thermocouples; high technology applications for sophisticated instruments and communication systems require very small, low current modules, whereas low-cost, high capacity modules are in demand for a growing number of commercial applications. Modules can be mounted in parallel to increase the heat transfer effect or can be stacked in multistage cascades to achieve high differential temperatures.

Should you use thermoelectric heat pumps?

Thermoelectric devices are not the solution for every cooling problem. However, you should consider them when your system design criteria include such factors as high reliability, small size or capacity, low cost, low weight, intrinsic safety for hazardous electrical environments, and precise temperature control.

OptoTEC Series - sub-miniature, low- and moderate capacity, low current thermoelectric modules for use in maintaining critical temperatures in systems where determining factors are high reliability, limited space, and minimal power consumption.

CP Series - low-cost, moderate- and high capacity, general-purpose modules for cooling equipment such as instrumentation, laboratory apparatus, consumer appliances, and for commercial and military applications.

MULTISTAGE- (Cascade) Series - Standard and custom multistage (cascade) TECs designed to meet requirements for large temperature differentials.

HEATPUMP- Assemblies - packages including FRIGICHIPS^® and heat exchangers, designed and fabricated to customer specifications.