A heat exchanger in a boiler transfers heat from the combustion gases to the water circulating in the system. Here's how it works step by step:
Combustion occurs: The boiler burns a fuel source (like natural gas, oil, or electricity), creating hot combustion gases.
Heat transfer to the heat exchanger: These hot gases flow through a heat exchanger—typically a coiled or finned metal tube or series of plates made of steel, copper, or aluminum.
Water circulation: Cold water from the central heating system is pumped through the heat exchanger.
Heat absorption: As the hot gases pass over the surfaces of the heat exchanger, heat is conducted through the metal into the water inside.
Hot water delivery: The now-heated water is circulated through radiators or to hot water taps, depending on the boiler type (combi or system boiler).
Gas expulsion: The cooled combustion gases are vented out through a flue.
In condensing boilers, there's an extra stage:
After the initial heat transfer, the remaining heat in the exhaust gases is used to preheat incoming cold water, extracting even more energy and improving efficiency. This process often creates condensate (water), which is drained from the boiler.
The exhaust gas generated by paper mills during the production process has the characteristics of high temperature, high humidity, and foul odor. If directly discharged, it not only pollutes the environment but also wastes a large amount of heat energy. To solve this problem, our company has developed a whitening and defogging heat recovery device for drying waste gas in paper mills.
working principle: Heat exchange principle: Using the principle of plate heat exchangers, heat is exchanged through a series of parallel metal plates. High temperature exhaust gas flows through one side of the plate, while fresh air flows through the other side, transferring heat through the plate wall to achieve waste heat recovery. Cooling and heating process: Firstly, the high-temperature exhaust gas is cooled to a temperature close to the ambient temperature, and then heated by a reheater to make the exhaust gas temperature higher than the ambient temperature, thereby eliminating the phenomenon of white mist. Technical advantages: Efficient and energy-saving: By recovering waste heat from exhaust gas, energy consumption and operating costs are significantly reduced. Environmental protection and emission reduction: effectively removing moisture and odorous components from exhaust gas, reducing pollution to the environment. Compact structure: small size, light weight, easy installation, and occupies less space. Application scenarios: Paper industry: Recovering heat during the paper drying process to preheat the air entering the dryer, improve drying efficiency, and reduce fuel consumption. Food processing industry: Recycling waste heat from the drying process of grains, vegetables, fruits, etc., to preheat fresh air and improve drying efficiency. Chemical industry: Recycling high-temperature waste gas from the drying process of chemical products for heating other process gases or air. Textile industry: used for the recovery of waste heat during the drying process of textiles, improving drying efficiency and energy-saving effects.
With the further development of China's economy, the use of green energy will be more and more extensive. Heat pump dehumidification dryers with plate type obvious heat recovery function have developed rapidly in recent years and have been widely used in the Yangtze River basin, southwest China and South China.
The unit using the inverse cano principle at the same time, combined with efficient heat recovery technology, in the whole drying dehumidifying process, through the duct the wet air within the chamber connected to the host using the sensible heat plate heat collector recovery of the sensible heat and latent heat of hot and humid air, thermal recycling, greatly improve the performance of the host, improve the drying speed and material quality. The waste heat can not only improve the performance of the unit, but also reduce the thermal pollution to the environment and alleviate the urban heat island effect.
The heat pump drying heat recovery system is not only used in the mud drying system, but also widely used in many other drying industries. It has the characteristics of good drying quality and high degree of automation, and is the best choice product for energy saving, green and environmental protection in the modern drying industry.
Heat pump dryers with and without heat recovery working principle
When the heat pump dryer dries the air, the air forms a closed cycle between the drying chamber and the equipment. The evaporator's heat absorption function is used to cool and dehumidify the hot and humid air, and the condenser's heat release function is used to heat the dry cold air, so as to achieve the effect of cycle dehumidification and drying.
The main difference between heat recovery function and heat pump dryers without heat recovery function lies in the different air circulation modes. The former is equipped with plate type sensible heat exchanger, which plays the function of pre-cooling and preheating in the air circulation process, reducing the load of compressor operation and achieving the purpose of energy saving.
Heat pump drying system operation mode
Energy saving analysis of heat recovery
Taking a heat pump dryer as an example, the air temperature of drying is designed to be 65℃, the relative humidity is 30%, the circulating air temperature is 65℃, the temperature before passing through the evaporator is 65℃, and the temperature after evaporation cooling is 35℃. The condenser needs to heat the air of 35℃ to 65℃ before it can be used.
After matching with BXB500-400-3.5 heat exchanger, 35℃ return air absorbs heat from exhaust air after passing through plate heat exchanger, and the temperature rises to 46.6℃. The condenser only needs to heat the air from 46.6℃ to 65℃ to meet the use requirements, greatly reducing the load of evaporator and condenser, thus reducing the power of the whole machine, achieving the purpose of energy saving.
Energy saving analysis of heat recovery
Selection and economic calculation
We are very glad to show you the calculation and selection software of plate heat exchanger jointly developed by us and Tsinghua University. If you need, please contact us!
With the rapid development of manufacturing industry, many products require drying and dehumidification treatment during the production process. These processes not only require efficient moisture removal, but also require maintaining the characteristics and quality of the material. Traditional drying and dehumidification methods often consume high energy and may have adverse effects on the environment, such as emitting greenhouse gases and other pollutants.
By adopting efficient heat recovery technology, waste heat can be maximally recovered and reused to reduce energy consumption. Heat recovery technology has been widely applied in multiple industries to improve energy efficiency and reduce operating costs. But in the field of drying and dehumidification, the potential of this technology has not been fully tapped. We customize and develop a heat recovery system that suits your specific production needs and on-site conditions. We carefully design the system layout for you to ensure minimal loss of thermal energy during conversion and transmission. Welcome to inquire via email.
In the low-temperature vegetable processing area, the main function of the ventilation heat exchanger is to ensure that the temperature of the processing environment is suitable to maintain the freshness and quality of the vegetables. Ventilation heat exchangers use efficient heat exchange technology to dissipate indoor heat while introducing external cold air or cooled air for effective temperature control. In addition, the ventilation heat exchanger in the low-temperature vegetable processing area also needs to consider humidity control, as excessive humidity may cause vegetable rot. Therefore, some ventilation heat exchangers are also equipped with humidity regulation functions to ensure that the humidity in the processing environment remains within an appropriate range. The sorting area of a supermarket or shopping mall is responsible for sorting, packaging, and delivering goods. The main function of the ventilation heat exchanger in this area is to provide fresh air and remove indoor turbid air and excess heat. The ventilation heat exchanger in the sorting area of supermarkets usually has a large air volume and efficient heat exchange performance to meet the needs of large spaces and high pedestrian flow. At the same time, they also need to have the characteristics of easy maintenance and cleaning to ensure long-term stable operation. Whether it is a low-temperature vegetable processing area or a supermarket sorting area, ventilation heat exchangers are indispensable and important equipment. They provide a comfortable and healthy working environment for these areas through efficient air conditioning and temperature control, which helps improve production efficiency and product quality. Our cross countercurrent plate heat exchanger is made of high-quality hydrophilic aluminum foil, epoxy resin aluminum foil, stainless steel, polycarbonate and other materials. The air flows partially in cross flow and partially in relative flow to avoid the transmission of odors and moisture. Applied to energy recovery in civil and commercial ventilation systems, as well as industrial ventilation systems. Fast heat conduction, no secondary pollution, good heat transfer effect.