Below is a list of Cooling Tower Systems manufacturers from Ontario, California. Cooling tower systems, sometimes referred to as heat rejection devices, provide cooling of water and other fluids through the removal of heat from the fluid. Essentially, a cooling tower is comprised of a water tower and a water reservoir pumping system. Cooling towers systems can be constructed from several construction materials, such as concrete, fiberglass, galvanized steel, stainless steel and wood; each material presents its own advantages.