![]() ![]() The higher the temperature difference (delta), the lower the maximum theoretical COP. The maximum COP of any refrigeration cycle is ultimately limited by the difference between the desired (cold side) and ambient (hot side) temperature (the temperature of the heat sink). In special applications, multiple coolers can be cascaded or staged together for lower temperature, but overall efficiency (COP) drops significantly. The "hot" side is attached to a heat sink so that it remains at ambient temperature, while the cool side goes below room temperature. ![]() When a DC electric current flows through the device, it brings heat from one side to the other, so that one side gets cooler while the other gets hotter. A thermoelectric module is made from three components the conductors, legs, and the substrate, and many of these modules are connected electrically in series, but thermally in parallel. Thermoelectric coolers operate by the Peltier effect (one of three phenomena that make up the thermoelectric effect). Thermoelectric legs are thermally in parallel and electrically in series. Operating principle Peltier element schematic. However, a well-designed Peltier cooler will be a mediocre thermoelectric generator and vice versa, due to different design and packaging requirements. When operated as a generator, one side of the device is heated to a temperature greater than the other side, and as a result, a difference in voltage will build up between the two sides (the Seebeck effect). When operated as a cooler, a voltage is applied across the device, and as a result, a difference in temperature will build up between the two sides. (See Thermoelectric materials.)Ī Peltier cooler can also be used as a thermoelectric generator. Many researchers and companies are trying to develop Peltier coolers that are cheap and efficient. Its main disadvantages are high cost for a given cooling capacity and poor power efficiency (a low coefficient of performance or COP). The primary advantages of a Peltier cooler compared to a vapor-compression refrigerator are its lack of moving parts or circulating liquid, very long life, invulnerability to leaks, small size, and flexible shape. This technology is far less commonly applied to refrigeration than vapor-compression refrigeration is. It can also be used as a temperature controller that either heats or cools. It can be used either for heating or for cooling, although in practice the main application is cooling. Such an instrument is also called a Peltier device, Peltier heat pump, solid state refrigerator, or thermoelectric cooler ( TEC) and occasionally a thermoelectric battery. A Peltier cooler, heater, or thermoelectric heat pump is a solid-state active heat pump which transfers heat from one side of the device to the other, with consumption of electrical energy, depending on the direction of the current. Thermoelectric cooling uses the Peltier effect to create a heat flux at the junction of two different types of materials. ![]()
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