The energy-saving application of frequency converter in HVAC system has significant advantages and broad prospects. By accurately adjusting the speed of equipment such as fans and water pumps, the output power of HVAC system can be accurately matched with actual demand, which can effectively reduce energy consumption.

1.Air conditioning system

Chilled water pump: In the air conditioning system, the chilled water pump is responsible for delivering chilled water to the indoor terminal equipment to take away the indoor heat; traditional chilled water pumps usually run at a fixed speed and cannot be adjusted according to the changes in air conditioning load. After installing the frequency converter, the water flow rate can be adjusted by adjusting the speed of the water pump according to the actual load of the air conditioning system. According to actual case statistics, the use of frequency converters to control chilled water pumps and cooling water pumps can achieve energy savings of 20% - 40%.

Air conditioning unit fan: The fan in the air conditioning unit is responsible for delivering processed air to each room. By adjusting the fan speed through the frequency converter, the air supply volume can be flexibly adjusted according to the indoor air quality and temperature requirements. After the air conditioning system of a large commercial building adopted the inverter to control the fan, the energy saving effect reached 15% - 30%.

2. Heating system

Hot water circulation pump: In the central heating system, the function of the hot water circulation pump is to promote the circulation of hot water in the pipe network and deliver heat to each user. After installing the inverter, the speed of the hot water circulation pump can be adjusted in real time according to the feedback signals of the outdoor temperature sensor and the indoor temperature sensor, so that the hot water flow rate matches the heating demand. Practice has proved that the use of inverter to control the hot water circulation pump can achieve energy saving of 15% - 35%.

Heating fan: For systems using hot air heating, such as heaters, air curtains, etc., the speed of the heating fan can be adjusted by the inverter, and the air supply volume and hot air temperature can be reasonably controlled according to the indoor temperature and space size. After the application of the inverter, the hot air heating system of an industrial plant has achieved significant energy saving effects and can save a lot of energy costs every year.

3. Ventilation system

Exhaust fan: The speed of the exhaust fan is controlled by the frequency converter, and the exhaust volume can be adjusted in real time according to the feedback signal of the indoor air quality sensor. When the indoor air quality is good, the exhaust fan speed is reduced to reduce the fan energy consumption; when the indoor population is dense and the air quality is deteriorating, the exhaust fan speed is increased to increase the exhaust volume. For example, in places with large personnel flow such as shopping malls and conference rooms, the use of frequency converters to control the exhaust fan can achieve energy savings of 20% - 30%.

Fresh air fan: The speed of the fresh air fan is adjusted by the frequency converter, and the fresh air volume can be flexibly adjusted according to the indoor and outdoor temperature, humidity and personnel needs. In spring and autumn, when the outdoor temperature is more suitable, the speed of the fresh air fan can be appropriately reduced to reduce the energy consumption of fresh air processing; in summer or winter, when the outdoor temperature is extreme, the speed of the fresh air fan can be accurately controlled according to the indoor environment needs to ensure the provision of appropriate fresh air volume while reducing energy consumption. After installing the frequency converter, the fresh air system of an office building has achieved an energy saving effect of 10% - 25%.