Waste heat recovery provides many opportunities in terms of sustainability, thanks also to the fact that there are various options from which to choose.
In the following paragraphs, we’re going to take a look at some of the most important technologies in this industry and how we could benefit from them.
But first, we need to define waste heat recovery itself.
As a process, waste heat recovery involves making use of all the heat energy stored in sources that otherwise are wasted. A Classical example of this is exhaust gases released by furnaces in plants.
As a strategy, waste heat recovery provides an additional source of energy and the reduction of generated energy waste.
There are some different technologies that can be used for such recoveries, including ORC (Organic Rankine Cycle), heat exchangers, load preheating and some low-temperature equipments.
Heat exchangers are devices that turn exhausted gases into combustion air. Combustion air is then used in furnaces to reduce the amount of fuel needed for them to work properly: combustion air enters at a high temperature, which allows it to contribute its energy to the one produced by the fuel.
Load preheating is a term that covers a lot of different technologies, including but not limited to stack melters and boiler feedwater preheating. In short, what all of those technologies have in common is the fact that they are able to preheat whatever is entering the system using the waste heat from the previous cycle.
Low-temperature options are a novelty, since waste heat recovery is usually based on using energy waste with high temperatures. Considering that a lot of energy waste we produce is at a low-temperature, is quite simple to understand that this kind of applications is being found and developed at an increasingly fast pace. Among the existing technologies, we have deep economizers, transport membrane condensers and direct/indirect contact condensation recoveries.