The need for Precision Environmental Control dates back to the invention of the ENIAC (Electrical Numerical Integrator and Computer) the worlds first main frame computer in the 1940's
The thermionic triode, a vacuum tube invented in 1907, enabled amplified radio technology and long-distance telephony. The triode, however, was a fragile device that consumed a substantial amount of power. In 1909 physicist William Eccles discovered the crystal diode oscillator. German physicist Julius Edgar Lilienfeld filed a patent for a field-effect transistor (FET) in Canada in 1925, which was intended to be a solid-state replacement for the triode. Lilienfeld also filed identical patents in the United States in 1926 and 1928.However, Lilienfeld did not publish any research articles about his devices nor did his patents cite any specific examples of a working prototype. Because the production of high-quality semiconductor materials was still decades away, Lilienfeld's solid-state amplifier ideas would not have found practical use in the 1920s and 1930s, even if such a device had been built. In 1934, German inventor Oskar Heil patented a similar device in Europe.
The first practically implemented device was a point-contact transistor invented in 1947 by American physicists John Bardeen, Walter Brattain, and William Shockley. The transistor revolutionized the field of electronoling ics, and paved the way for smaller and cheaper radios, calculators, and computers, among other things.
This transition to solid state electronics from the vacuum tube technology with the miniaturization to chips paved the way and allowed the practical development of large scale main and mini frame computers. Packing more hardware into smaller and smaller space also increased the heat density accompanied by tight tolerance requirements generated the need for cooling giving birth to Precision Environmental Systems