Waste heat recovery refers to the process of capturing and reusing heat that is produced in industrial processes, power generation, and other energy-intensive operations but would otherwise be released into the environment. Recovering this heat improves overall energy efficiency, reduces fuel consumption, and lowers greenhouse gas emissions. Various technologies have been developed to utilize waste heat effectively across different sectors such as manufacturing, power plants, transportation, and commercial buildings. One of the most common technologies used for waste heat recovery is the heat exchanger. Heat exchangers transfer heat from a hot fluid or gas to a cooler fluid without mixing them. Common types include shell and tube heat exchangers, plate heat exchangers, and recuperators. In industries such as steel, cement, and chemical manufacturing, exhaust gases from furnaces and kilns contain significant heat energy. Heat exchangers capture this heat and use it to preheat combustion air, boiler feedwater, or other process fluids. This reduces the amount of fuel required for heating and improves process efficiency. Another widely used technology is the regenerative heat recovery system. Regenerators store heat from hot exhaust gases in a thermal storage medium such as ceramic bricks or metal structures and then transfer that heat to incoming cold air or gas. This system is often used in glass manufacturing, steel plants, and high-temperature furnaces. Regenerative burners in industrial furnaces significantly improve thermal efficiency by recovering and reusing large amounts of heat that would otherwise be lost through exhaust gases. Waste heat boilers are another important technology for recovering energy