Common types of heat exchangers in agricultural ventilation

Plate heat exchanger: Its advantages are compact structure, high heat transfer efficiency, small footprint, and easy disassembly, cleaning, and maintenance. A ventilation system suitable for various agricultural facilities such as greenhouses and breeding farms, which can achieve efficient sensible heat exchange.
Heat pipe heat exchanger: With the heat pipe as the core heat exchange element, it utilizes the phase change heat transfer of the working fluid inside the pipe to achieve heat transfer. Heat pipe heat exchangers have the advantages of high heat transfer efficiency, good isothermal properties, and the ability to achieve long-distance heat transfer. In the agricultural field, especially in places with strict requirements for environmental temperature and humidity control, such as animal rooms and laboratories, heat pipe heat exchangers can effectively recover waste heat while avoiding cross contamination and adapting to a wide temperature range environment.
Shell and tube heat exchanger: composed of shell, tube bundle, tube plate and other components, the fluid flows in the tube and shell sides for heat exchange. The shell and tube heat exchanger has a sturdy structure and can withstand high pressure and temperature, making it suitable for large-scale agricultural facilities that require high stability and reliability of ventilation systems, such as large greenhouse clusters or large-scale breeding farms. By installing fins on the tube, its heat transfer efficiency can be further improved and its applicability in agricultural ventilation can be enhanced.

Heat recovery system for paint booth

The heat recovery system of the paint booth mainly recovers the heat from the exhaust gas discharged from the paint booth through a heat exchange device, which is used to preheat the fresh air or other heating needs entering the paint booth, in order to achieve energy-saving purposes.
In the heat exchanger, the high-temperature exhaust gas discharged from the paint booth and the fresh air (or other heated medium) entering the paint booth flow on both sides of the partition wall, and heat is transferred through the partition wall. Due to the lack of direct contact between exhaust gas and fresh air, the mixing of the two is avoided, ensuring the cleanliness of the air. The heat of high-temperature exhaust gas is transferred to the partition wall, which then transfers the heat to fresh air, raising the temperature of the fresh air and achieving heat recovery and utilization.

Application of Commercial Ventilation Heat Exchanger

Our commercial ventilation heat exchanger is a device used in the ventilation system of commercial buildings. Its main application principle is to use heat exchange technology to recover heat or cold from indoor polluted air while discharging it, in order to preheat or pre cool the fresh outdoor air introduced, thereby achieving energy conservation and improving indoor air quality. The specific principle is as follows:
Ventilation principle
Commercial ventilation heat exchangers are usually installed in the ventilation systems of commercial buildings, which use mechanical ventilation to expel polluted indoor air and introduce fresh outdoor air into the room.
This can ensure the freshness and circulation of indoor air, meet people's breathing needs in commercial environments, and also help maintain appropriate indoor temperature and humidity.
Heat exchange principle
There is a special heat exchange core inside the heat exchanger. When the air discharged from indoors and the air entering from outdoors flow in the heat exchange core, heat transfer occurs due to the temperature difference between the two.

The role of heat exchanger in sludge drying process

Heating medium: The heat exchanger transfers heat to the drying medium (such as air, nitrogen, etc.) to increase its temperature. The hot drying medium comes into full contact with the sludge and transfers heat to the sludge through convection, conduction, and other means, causing the water in the sludge to absorb heat and evaporate into steam, thereby achieving the drying of the sludge.
Recycling waste heat: During the sludge drying process, a large amount of exhaust gas containing heat is generated. The heat exchanger can cool the exhaust gas and recover the heat from it. The recovered heat can be used to preheat fresh air or drying medium entering the dryer, as well as for other process links that require thermal energy, thereby improving the energy utilization efficiency of the entire drying system and reducing energy consumption.
Removing moisture: During the sludge drying process, the heat exchanger can not only heat the drying medium, but also condense the water vapor in the drying medium into liquid water through cooling, thereby achieving dehumidification of the drying medium. Dehumidification of the drying medium is beneficial for improving its ability to absorb moisture from sludge and enhancing the drying effect. For example, in some sludge drying systems that use circulating drying media, by setting up cooling heat exchangers to dehumidify the circulating air, the drying speed of sludge can be increased by 20% -30%.

Application of Heat Pump Heat Exchanger in Drying Chemical Materials

Heating of drying medium: In the drying process of chemical materials, it is necessary to heat the drying medium (such as air, nitrogen, etc.) to a certain temperature to improve the drying efficiency. Heat pump heat exchangers can elevate the temperature of thermal energy or industrial waste heat in the environment and use it to heat drying media. For example, when drying pesticide intermediates, a heat pump heat exchanger is used to heat the air and raise the air temperature to 60-80 ℃, providing the required heat for the drying process. Compared with traditional electric or gas heating methods, it can significantly reduce the drying cost.
Recycling of waste heat from drying exhaust gas: The exhaust gas emitted during the drying process of chemical materials usually contains a certain amount of heat and moisture. If directly discharged, it will cause energy waste and environmental pollution. A heat pump heat exchanger can cool dry exhaust gas, recover its heat, and condense the moisture in the exhaust gas, achieving the goal of waste heat recovery and energy conservation and emission reduction. The recovered heat can be used to preheat fresh drying media or other processes, improving energy utilization efficiency.

The role of heat pump heat exchangers in the chemical industry

1. Maintain reaction temperature: Many chemical reactions require specific temperature ranges to ensure reaction rate and product quality. The heat pump heat exchanger can adjust the temperature inside the reaction vessel to timely remove or supplement the required heat generated by the reaction, so that the reaction can proceed under stable temperature conditions. For example, in the polyester synthesis reaction, it is necessary to strictly control the reaction temperature at around 200-250 ℃. The heat pump heat exchanger can accurately adjust the temperature of the reaction kettle to ensure the smooth progress of the reaction.
2. Recycling reaction waste heat: Some chemical reactions are exothermic reactions, and if the large amount of waste heat generated is not utilized, it will not only cause energy waste, but also may cause thermal pollution to the environment. Heat pump heat exchangers can recover the heat from high-temperature hot water or steam discharged from the reaction kettle, raise it to a higher temperature level, and use it for other processes that require heat, such as preheating reactants, heating process water, etc., thereby improving the energy utilization efficiency of the entire chemical production process.

What industrial fields are heat pump heat exchangers used in?

Process heating in industrial production: In some industrial production processes that do not require particularly high temperature but require a large amount of heat energy, such as food processing, textile printing and dyeing, wood drying, etc., heat pump heat exchangers can use industrial waste heat or environmental heat energy to provide the required heat for the production process, achieving energy recovery and energy conservation and emission reduction.
Industrial wastewater waste heat recovery: Many industrial production processes generate a large amount of wastewater, which often contains a certain amount of heat. Heat pump heat exchangers can extract heat from wastewater and use it to preheat production water or other processes that require thermal energy, reducing energy consumption and production costs for enterprises.

Dryer Exhaust Heat Recovery Exchanger Technical Overview

1. Exchanger Types

  • Plate Heat Exchanger
    Compact structure with high heat transfer efficiency, suitable for low-temperature exhaust (<200°C) with minimal corrosiveness. Easy to clean, ideal for small to medium-sized dryers.

  • Rotary Wheel Exchanger
    Transfers heat via a rotating wheel, suitable for high-flow, low-temperature-difference exhaust recovery. High efficiency, best for large-scale drying systems, but requires more space.

2. Design Considerations

  • Exhaust Characteristics
    Evaluate exhaust temperature (typically 80–200°C), flow rate, humidity, and dust content. Corrosive gases require resistant materials (e.g., stainless steel).

  • Heat Recovery Efficiency
    Efficiency ranges from 50%–80%, depending on temperature difference and heat transfer area. Balance efficiency with pressure drop to maintain exhaust performance.

  • Maintenance and Cost
    Plate exchangers are easy to disassemble and clean, with low maintenance costs. Rotary wheel exchangers suit continuous operation but have higher initial costs.

3. Application Scenarios

  • Plate Heat Exchanger: Used in small to medium dryers, such as in food or textile industries, for recovering low-temperature exhaust to preheat fresh air.

  • Rotary Wheel Exchanger: Applied in large industrial dryers, like paper or chemical material drying, for handling high-flow exhaust.

The research and development prospects of new technologies for waste heat recovery

Efficient heat exchanger technology: Developing heat exchangers with higher heat transfer efficiency, lower resistance, and smaller volume, such as plate heat exchangers and heat pipe heat exchangers designed with new materials and optimized structures, to improve the efficiency and economy of industrial heat recovery.

Intelligent control system: Develop an intelligent industrial heat recovery control system using technologies such as the Internet of Things, big data, and artificial intelligence. By monitoring and analyzing the thermal parameters in the production process in real-time, automatically adjusting the operating status of the heat recovery equipment, optimizing the control of heat recovery, and improving the stability and energy utilization efficiency of the system.

New energy storage technology: Research and apply new energy storage technologies such as phase change energy storage materials and thermochemical energy storage to solve the problems of industrial waste heat discontinuity and instability. By storing heat during the generation of waste heat and releasing it when needed, flexible utilization of waste heat can be achieved, improving the overall performance of the heat recovery system.

New application areas of waste heat recovery

Data center heat recovery: With the rapid development of data centers, their energy consumption and heat dissipation issues are becoming increasingly prominent. Recovering the waste heat generated by data center servers and other equipment for heating, hot water supply, or preheating of other industrial processes in surrounding buildings, achieving green and energy-saving operation of data centers.

Thermal management of electric vehicle batteries: During the charging and discharging process of electric vehicle batteries, a large amount of heat is generated. Developing an efficient battery thermal management system to recover the waste heat generated by the battery for energy supply to in car heating or other auxiliary equipment can not only improve the performance and lifespan of the battery, but also enhance the overall energy utilization efficiency of electric vehicles.

Industrial waste heat driven refrigeration system: Utilizing industrial waste heat to drive absorption refrigeration, adsorption refrigeration and other systems, providing cooling capacity for the cooling needs in industrial production processes. This method can reduce the energy consumption of traditional electric refrigeration systems, achieve cascade utilization of waste heat, and improve the comprehensive utilization efficiency of energy.

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