Industrial facilities and process manufacturers in pharmaceutical, bio-diesel, pulp and food process industries have been using waste heat exchangers for decades to transfer from heating to cooling needs and back again. Recently, engineers have been working the designs for waste heat exchangers by replacing typical coolants with gases or liquids which need to be heated anyway, allowing facilities to recycle their own energy via their own waste heat exchanger system. Automotive radiators, heater cores and evaporators all work in this way, with tubes of liquid coolant absorbing excess energy from the engine, which is then blown by fans into the car interior as heating. This is a simple example of the use of a waste heat exchanger system that we see everyday.

Waste heat found in the exhaust gas of various processes or even from the exhaust stream of a conditioning unit can be used with a waste heat exchanger to preheat the incoming gas. This is one of the basic methods for recovery of waste heat. Many steel making plants use this process as an economic method to increase the production of the plant with lower fuel demand. In this way, waste heat exchanger systems are already helping to provide green energy.

Industrial process facilities recover otherwise wasted heat energy using waste heat exchangers, but on a much larger scale. Typical shell and tube heat exchangers use a "bundle" of tubes encased in a shell, in which heat energy is transferred from hot liquids or gases flowing through in through the tubes to liquid or coolant which flows over and around the tubes within the shell, capturing heat energy and flowing back out. Plate and flat plate heat exchangers work similarly with hot and cold liquid chambers separated by metal plates. Refrigerators use flat plate heat exchangers to create cool air. In industrial manufacturing, these same heat exchangers can be used not only to cool liquids and air which have been heated by processing, but to input a portion of that heat energy back into manufacturing processes.

This hot gas must be released somehow. If it is directed into a waste heat exchanger instead of into the atmosphere, a large portion of energy may be recovered. A waste heat exchanger system would capture the hot gas through a duct and carry it to an air-to-liquid shell and tube heat exchanger. The extra water vapor would condense and collect for reuse within the waste heat exchanger, transferring heat energy to the liquid inside the pipes. The pipes in turn flow to the coils below the vat, using the energy that was released from the vat to aid in the heating required at the beginning of the process.

Recuperating wasted energy via a waste heat exchanger can result in significant savings for facilities across the manufacturing spectrum. Energy can be transferred from air to air, air to liquid or liquid to liquid in any manufacturing processes which uses or requires heat. Capturing process heat to warm facilities during cold weather can save enormously on facility heating costs, causing a well-build, efficient waste heat exchanger system to pay for itself, sometimes within a few months.