Although he didn’t start studying physics until he retired from the clock-making business at age 30, French native Jean Peltier made immense contributions to science that still reverberate today. Even with the primitive tools available to him in the early 19th century, he laid the scientific foundation for air conditioning and heating technology that would be developed years later.
Peltier’s enduring legacy is the discovery of a phenomenon that bears his name. The “Peltier effect” takes place when an electrical current is sent through a pair of different metals that have been connected to one another at two junctions. One junction between the two metals becomes warm, while the other cools down in what amounts to an electrically driven transfer of heat from one end of the unit to the other. When the cold junction was put inside an insulated box, it became the first refrigerator, albeit a low-efficiency unit.
Although Peltier failed to understand the physics behind the phenomenon, history credits him with the discovery of thermoelectric cooling.
In the early stages of commercial heating and air conditioning, Peltier effect systems quickly gained widespread acceptance. Over time, they were replaced by other technology for the same reason they became popular to begin with: although the process and utilization of the effect is simple, it is also inefficient and consumes large amounts of electricity while producing excessive condensation. Despite the negatives, the Peltier effect is still used today because it has some advantages over more efficient compressor technology. For example, there are no moving parts and very little maintenance is required.
Even though he achieved his greatest fame for the research that bears his name, Peltier is said to have put greater thought into other scientific investigations. In 1840, he unveiled his theory of electrostatic induction, a means of charging a conductor by positioning another charged object nearby to exert a pull on every charge of one sign, and then grounding the conductor to remove the other group of charges, leaving a net charge behind.
Peltier left behind a collection of numerous papers devoted to physical phenomena, including anatomy, microscopy and meteorology. In numerous papers, he writes at length about atmospheric electricity, waterspouts, the polarization of skylight, the temperature of water in the spheroidal state, and the boiling point at high elevations. There are also many writings devoted to what Peltier referred to as “curious points of natural history,” but his name will forever be linked with the thermal effects of voltaic circuits. Peltier died in Paris, France, in 1845, at the age of 60.