3. Applications using thermoelectric coolers

Commercially available TE coolers are used in applications where design criteria of the cooling system include factors such as high reliability, low weight, small size, intrinsic safety for hazardous electrical environments and accurate temperature control. TE coolers are more appropriate for unique applications such as space missions, medical and scientific equipment where low COP is not an apparent disadvantage.

TE cooling devices are used for cooling small volumes, such as portable and domestic refrigerator, portable icebox and beverage can cooler [12, 16–21], where the cooling requirements are not too high. In general, the COP for both domestic and portable thermoelectric refrigerators is usually less than 0.5, when operating at an inside/outside temperature difference between 20 and 25C.

Electronic devices like PC processors produce very large amount of heat during their operation which add great challenge to the thermal management as reliable operation temperature for these electronic devices has to be maintained. TE cooling devices have also been applied to scientific and laboratory equipment cooling for laser diodes and integrated circuit chips [22] to reduce the thermal noise and the leakage current of the electronic components where conventional passive cooling technologies cannot fully meet the heat dissipation requirements. For example, cooling CdZnTe detectors for X-ray astronomy between 30 and 40C can reduce the leakage current of the detectors and allows the use of pulsed reset preamplifiers and long pulse shaping times, which significantly improves their energy resolution. Integrating thin film TE coolers with microelectronic circuits has been implemented using micromachining technology.

TE cooler appears to be especially favorable for automotive applications [23]. Besides the automobile air-conditioning system and automobile mini refrigerators, researchers also utilized TE device to control car seat temperature to either cooling down or heating up [24].

Some researchers are trying to improve thermoelectric domestic air-conditioning systems [25–27] hoping that these systems can be competitive with the current widely used vapor compression systems. They investigated TE cooling devices for small-scale space's conditioning application in buildings [26]. A TE cooling unit was assembled and generated up to 220 W of cooling capacity with a maximum COP of 0.46 under the input electrical current of 4.8 A for each module.

Active thermal window (ATW) and transparent active thermoelectric wall (PTA) were also introduced for room cooling application in applications where conventional air-conditioning system is not easy to install [28, 29]. Thermoelectric cooling has also been applied in other occasions, such as generating fresh water [30–33] and active building envelope system [7, 34].

TE systems can be directly connected to a PV panel. Since TE devices are low voltage driven devices, they can accept a power supplied by PV panel without conversion. This advantage makes TE devices attractive for building air-conditioning applications [27, 30]. This solar cooling technique can reduce the energy consumption and the environmental impact issues raised by conventional refrigeration and air-conditioning systems. Batteries can also be used to store DC voltages when sunlight is available while supplying DC electrical energy in a discharging mode in the absence of daylight. A battery charge regulator is needed to protect the battery form overcharging. Solar thermoelectric can be used in cooled ceiling applications to remove of a large fraction of sensible cooling load. In this case, the TE modules are connected in series and sandwiched between aluminum radiant panels and heat pipe sinks in ceilings [35].
