How Does the Efficiency of a Heat Exchanger Affect the Performance of a Heat Recovery System?

The efficiency of a heat exchanger exerts a significant influence on the performance of a heat recovery system, which is manifested in several aspects such as energy recovery, system operation stability, environmental protection benefits, and economic efficiency.

Energy Recovery Efficiency

Heat Transfer Capacity: The efficiency of a heat exchanger directly determines its ability to recover heat from the exhaust gas and transfer it to the supply air and combustion air. A high-efficiency heat exchanger can transfer more heat from the exhaust gas to the fresh air, resulting in a higher preheating temperature for the supply air and combustion air. For instance, a high-efficiency plate heat exchanger can increase the supply air temperature by 30℃ - 50℃, while a low-efficiency one might only achieve an increase of 10℃ - 20℃. This indicates a significant reduction in heat recovery and a substantial decrease in the energy-saving effect of the system.

Energy Utilization Factor: The higher the efficiency of the heat exchanger, the higher the energy utilization factor of the entire heat recovery system. Ideally, a high-efficiency heat exchanger can enable the energy recovery and utilization rate of the system to reach 70% - 80%, while a low-efficiency heat exchanger may reduce the energy recovery and utilization rate to 30% - 40%, leading to a large amount of recoverable energy being wasted.

System Operation Stability

Temperature Stability: A high-efficiency heat exchanger can transfer heat from the exhaust gas to the air more stably, maintaining the temperatures of the supply air and combustion air within a relatively stable range. This contributes to the stable operation of the drying and combustion processes in the Yankee hood, reducing issues such as product quality problems or incomplete combustion caused by temperature fluctuations. If the heat exchanger is inefficient, it may result in significant temperature fluctuations in the supply air and combustion air, affecting the continuity of production and the consistency of product quality.

Impact of Pressure Loss: The efficiency of a heat exchanger is related to factors such as flow channel design. A high-efficiency heat exchanger can achieve good heat transfer while maintaining low pressure loss, ensuring the smooth flow of exhaust gas and air within the system. In contrast, a low-efficiency heat exchanger may cause significant pressure loss due to poor flow channel design or fouling, affecting the operation of fans and other equipment. This might even lead to the system malfunctioning, increasing the maintenance costs and failure risks during system operation.

Environmental Protection Benefits

Reduced Pollutant Emissions: A high-efficiency heat exchanger can fully preheat the combustion air, promoting more complete fuel combustion and thus reducing the emissions of pollutants such as carbon monoxide and hydrocarbons. Statistically, for every 10% increase in heat exchanger efficiency, carbon monoxide emissions during combustion can be reduced by 15% - 20%, helping enterprises meet more stringent environmental requirements.

Greenhouse Gas Emission Reduction: An efficient heat recovery system reduces the demand for additional energy by improving energy utilization efficiency, thereby indirectly reducing greenhouse gas emissions. The improvement in heat exchanger efficiency can significantly increase the greenhouse gas emission reduction of the entire system, which is of great significance for environmental protection.

Economic Efficiency

Reduced Operating Costs: A high-efficiency heat exchanger can increase heat recovery, reduce reliance on external energy sources, and lower energy consumption costs. For example, in a large paper mill, a heat recovery system equipped with a high-efficiency heat exchanger can save hundreds of thousands of yuan in energy costs annually.

Extended Equipment Service Life: Due to the high efficiency of the heat exchanger, the system can operate more stably, reducing the damage to equipment caused by factors such as temperature and pressure. This extends the service life of related equipment such as the Yankee hood and fans, reducing equipment renewal and maintenance costs and bringing significant economic benefits.