A heat exchanger is one of the most widely used devices in thermal installations, both at the construction, tertiary and industrial levels. Its use is basic in all types of air conditioning or cooling systems, air conditioning, energy transmission or in chemical processes. Heat transfer occurs through convection and conduction.Different types of heat exchange systemsclassification of heat exchange systems can be performed using a variety of different criteria. Given the degree of contact between the liquids, they are grouped into two different types.:Heat exchanger for direct contact ventilation In direct contact heat exchangers, heat exchange occurs through a physical mixture of liquids involved in the process.Indirect contact heat exchanger There is no direct contact between liquids in this heat exchanger, and they never mix. Liquids are separated by a solid barrier and may not match at the same time.Using heat exchangers for energy recovery Heat exchangers are widely used in all types of air conditioning and hot water plants, but they can also be used for energy recovery in various processes, which significantly increases energy efficiency. The most important applications in this field are:- Heat recovery for air- Purge heat recovery- Recuperators for gases or economizers- Condensing heat recuperators, Therefore, heat exchangers are not only the basic equipment for the operation of any power plant, but also a key system for increasing energy efficiency and reducing energy consumption.Flue gas reclaimers are devices for local ventilation systems that are indispensable in rooms such as kitchens.The absence of an exhaust system means that heat, smoke and toxic gases generated during combustion circulate around the environment, spreading to other rooms in the house or building and causing problems with indoor air pollution in the form of smoke, odors, moisture and temperature changes.What is a flue gas utilizer In general, ventilation aims to replace a part of the air considered undesirable with another, which allows you to maintain indoor air in a degree of pollution, temperature, humidity, etc., corresponding to the conditions necessary for health and well-being.When determining the ventilation system required for a room, several aspects must be considered:- Definition of the function performed.- Install the appropriate ventilation system: external or local.- Calculate the required amount of air.- Identify the air intake points and surface.- Set the air circulation path.With all this, it seems obvious that the ideal ventilation system would be a localized ventilation system, which would be achieved by installing smoke hoods. This is the most rational and economical system, as well as the only effective system if we want to control toxic or smoke emissions. tsescort.org/trans/spain/madrid/