Study And Application Of Energy-saving Technology Using Inverter For The Central Air Conditioner

In accordance with the normal Chinese standards, the Central Air Conditioner System (CACS) is designed under the highest air temperature and the full load of working surroundings. There exists much reserve room to be exploited. However, the CACS in the 97 percent of the time works under the 70 percent of the full load in a wave motion, therefore the CACS doesn't work under the full load, especially when the cold wind is needed less, the main processor of CACS works under the less load. In order to ensure better function state and better running efficiency, how to enhance the running efficiency and reduce energy consumption of the Cooling Water System (CWS), the Freezing Water System (FWS), terminal equipments such as air-blower is of great importance. In recent years, with the fast development of IC, the price of inverter has been decreased sharply; the reliability of inverter has been strengthened; the capacity of the inverter has been enlarged; therefore, the application of inverter to regulate the volume of wind and the volume of the flow at the air-blower and the water pump type machine becomes more and more realistic. It is vital to save energy and increase the economic benefits. The thesis discusses firstly the principles of energy-saving of CACS, and then discusses that the temperature of surroundings works on the inverter through the temperature-controller; and then regulating of the turning speed of the air-blower and the water pump electromotor is controlled the frequency conversion; and at last, the changes of the volume of wind and the volume of flow are controlled by the turning speed of electromotor. Under these above conditions the aim of energy-saving is reached. So, according to the actual situation of N-MART (in Nanchong, Sichuan, China), the plan of energy-saving is desigened as follows: The installation of inverter in the air-blower, the cooling water pump, the freezing water pump can, to a great extent, economize the power consumption of the water pump air-blower, and at the same time, the inverter has the functions to modulate the frequency and regulate the voltage, and the starting of the water pump becomes the soft starting, which does little harm to the electrified wire netting, and the inverter is controlled by the free level. The smooth starting of electromotor with no shock noises improves its service life. This kind of technological improvement decreases the business cost efficiently. Especially in the emergency of power supply, the power consumption of CACS is decreased successfully, which produces better economic benefits and society benefits.