Termopiiirikaa

Termopiiirikaa is a Finnish term that denotes an array or assembly of thermopiles, devices that convert thermal energy into electrical energy or detect infrared radiation. A thermopile consists of multiple thermocouples connected in series to increase voltage or in parallel to increase current. In a termopiiirikaa, many such thermoelement junctions are arranged to maximize exposure to a heat source or to radiant infrared energy, while a reference temperature is maintained at the opposite ends of the array.

Operating principle and design. Each thermocouple in the array generates a small voltage from the temperature difference between its hot and cold junctions, a manifestation of the Seebeck effect. By connecting many junctions in series, the voltages add up to a usable output. In infrared sensing applications, the thermopile absorbs radiant heat, inducing a measurable voltage proportional to the incident radiation or surface temperature. The materials and geometry of the thermoelements, the optical window, and the thermal isolation of the housing determine sensitivity, response time, and spectral response.

Materials and fabrication. Thermopile elements commonly use thermoelectric materials such as bismuth telluride or other alloys, and are mounted on ceramic or silicon substrates with protective housings. In infrared implementations, specialized coatings and windows are used to optimize absorption in the intended wavelength range and to minimize thermal losses.

Applications. Termopiiirikaa find use in non-contact infrared thermometry, flame and gas detection, industrial process monitoring, and low-power energy harvesting for sensors and remote devices. They offer solid-state reliability, long lifetimes, and no moving parts, but typically provide limited power density and require careful calibration and thermal management.

See also: thermopile, Seebeck effect, thermoelectric generator.