Guide to improving energy efficiency of air-cooled screw chillers

As a common refrigeration equipment, air-cooled screw chillers are widely used in air-conditioning systems of industrial production, commercial places and large buildings. In the current environment of advocating energy conservation and emission reduction, how to improve its energy efficiency has become the focus of industry attention. Improving the energy efficiency of air-cooled screw chillers not only helps to reduce operating costs, but also reduces the impact on the environment, with significant economic and environmental benefits.

Optimize equipment selection

Matching the appropriate unit capacity

When choosing an air-cooled screw chiller, the actual cooling load demand must be accurately calculated. A unit capacity that is too large will result in long-term low-load operation and reduced energy efficiency; a unit capacity that is too small will not be able to meet demand and will start and stop frequently, which will also consume energy. For example, for a commercial complex, it is necessary to comprehensively consider factors such as the flow of people in different areas and at different times and the heat dissipation of equipment, determine the accurate cooling load through detailed load calculation software or professional formulas, and then select a unit model that matches it to avoid the "big horse pulling a small cart" phenomenon.

Use high-efficiency compressor

The compressor is the core component of the chiller, and its performance has a significant impact on energy efficiency. Compared with traditional compressors, the new high-efficiency spiral rotor compressor can be 20%-30% more energy efficient. Some compressors use a 5:6 asymmetric rotor tooth profile to optimize the gas compression process and reduce energy loss. In the design of the compressor motor, high-efficiency silicon steel sheets and special grooves are selected, combined with internal and external omnidirectional cooling channels, which can enable the motor to perform at a higher efficiency under any load.

Consider a Quality Heat Exchanger

As key components of heat exchange, the performance of the condenser and evaporator is directly related to the energy efficiency of the unit. High-quality condensers are made of high-efficiency copper tubes to increase the heat exchange area and improve the heat dissipation effect. Some advanced condenser designs optimize the air duct structure to fully exchange heat between air and refrigerant, reduce the condensation temperature, and reduce the power consumption of the compressor. The evaporator also uses high-efficiency heat exchange materials to ensure efficient and stable heat transfer between the refrigerant and the cooled medium, thereby improving the overall refrigeration efficiency.

Optimize operation management

Precisely control the unit running time

Reasonably set the unit operation time according to actual needs to avoid unnecessary idling. For office spaces that only use air conditioning during the day, the intelligent control system can accurately set the start and stop time of the unit. It can also be combined with the pre-cooling or pre-heating needs of the building to advance or postpone the unit operation, reduce the operating time and reduce energy consumption.

Increase unit load factor

Try to make the units run at a state close to the rated load. By reasonably distributing the cooling load, you can avoid multiple units running at low load at the same time. Under partial load conditions, an intelligent control system is used to automatically adjust the number and load of running units according to actual cooling demand, so that the running units remain in the efficient working range.

Optimize unit operating conditions

Finely adjust the parameters of each component of the unit to keep the unit in the best working condition. Appropriately lowering the compressor exhaust temperature can reduce energy loss during the compression process; reasonably controlling the condenser inlet temperature can improve heat dissipation efficiency. By real-time monitoring of the unit's operating data and using advanced control algorithms, dynamic adjustment of various parameters can ensure efficient and stable operation of the unit.

Use energy-saving technologies and equipment

Frequency conversion technology application

Equip key components such as compressors, condenser fans and water pumps with frequency conversion devices. Frequency conversion technology can automatically adjust the speed of the equipment according to the actual load changes, avoiding energy waste caused by constant speed operation of the equipment. When the cooling load decreases, the speed of the compressor and fan will decrease accordingly, reducing energy consumption. According to statistics, the use of frequency conversion technology can save 15%-30% of energy for the unit.

Intelligent control system upgrade

The introduction of advanced intelligent control systems enables comprehensive monitoring and precise control of the unit. The intelligent system can collect real-time information such as unit operating parameters, ambient temperature, and cooling load changes, and automatically optimize the unit operation strategy through data analysis and processing. The condenser fan speed is adjusted according to the outdoor temperature, and the compressor energy output is dynamically adjusted according to the cooling load changes to ensure that the unit always operates in the best state.

Natural cooling technology integration

Under suitable climatic conditions, natural cooling technology is used to assist refrigeration. For example, when the outdoor air temperature is low, the outdoor low-temperature air is used to exchange heat with the chilled water to reduce the chilled water temperature and reduce the compressor working time and load. Natural cooling technology can significantly reduce the energy consumption of the unit, especially in cold areas or transitional seasons, the energy-saving effect is more significant.

Strengthen maintenance

Clean the condenser and evaporator regularly

During long-term operation, dust and dirt are easily accumulated on the surface of the condenser and evaporator, which affects the heat exchange effect. Regularly use professional tools and cleaning agents to thoroughly clean them. Use a high-pressure water gun to wash the condenser fins and use chemical cleaning agents to circulate and clean the evaporator pipes to keep the equipment surface clean, improve heat exchange efficiency, and reduce energy consumption.

Replace the filter element of the dry filter in time

The filter drier is an important component to ensure the normal operation of the system, and its filter element needs to be replaced regularly. If the filter element is clogged, the refrigerant flow rate will be reduced, the refrigeration efficiency will be reduced, and the energy consumption will increase. According to the requirements of the equipment maintenance manual, regularly check and replace the filter drier element to ensure the purity and stable flow of the refrigerant in the system.

Check the compressor oil system

Good lubrication of the compressor is the key to its efficient and stable operation. Regularly check the compressor lubricating oil level and oil quality, and replenish or replace the lubricating oil in time. Ensuring the normal operation of the lubricating oil system can reduce the wear of compressor parts, reduce mechanical friction loss, improve the energy efficiency of the compressor, and extend the service life of the equipment.

Improving the energy efficiency of air-cooled screw chillers is a systematic project, covering multiple aspects such as equipment selection, operation management, energy-saving technology application and maintenance. By comprehensively applying the above methods, the energy efficiency of the unit can be effectively improved, and the win-win goal of energy conservation, emission reduction and economic benefits can be achieved. In actual applications, it is necessary to formulate personalized energy efficiency improvement plans based on specific working conditions and needs, and continuously optimize and adjust to ensure that the unit is always in an efficient operating state.