Design And Implementation Of ICE Storage Air-Conditioning Monitoring System

At present, building energy consumption of China accounts for 23% of total energy consumption and 21% of total power consumption, with a trend of continuing growth. Energy for heating, ventilation and air-conditioning (HAVC) in public buildings shows a significant saving potential. As electricity consumption for HVAC system increasing, a contradiction between supply and demand of electricity peak is more prominent. Therefore, demand side management (DSM), with a main idea of "peak load shifting, load balancing", has been proposed. A set of incentive polices and management policies have been implemented. In the context of building energy efficiency and national electricity system reform, ice storage air-conditioning system has got the fast development.With advantages in saving initial investment, operating cost, transportation energy consumption and space, ice storage technology has been successfully applied in theaters, office buildings, shopping malls, hotels and other large public buildings. However, irrationalities of the control system in the ice storage central air-conditioning system result in difficulty to realize its economy, even the appearance of even serious deviation from the operating parameters of the design parameters. Lack of effective operational management is one of the main reasons for impeding ice storage air-conditioning technology popularization and application. Therefore, there is an urgent need to develop an automatic control system for ice storage central air-conditioning.Aiming these problems, an ice storage central air-conditioning system in an electricity production scheduling center has been taken as an example in this paper. Combining drawings and process requirements of HVAC, this paper in-depth studied operating characteristics of the ice storage air-conditioning system, and analyzed needs of users. The composition, structure and practical solutions of the monitoring system were proposed. Based on an embedded programmable logic controller (PLC) technology, PID control technology, single bus temperature acquisition technology, Visual Basics 6.0 programming techniques, etc., the design and implementation of the ice storage central air-conditioning automatic control system were carried out. The main contents are as follows:1. With an in-depth understanding of project production management and information technology conditions, eight basic functions, six auxiliary functions and three additional features of the automatic control system were defined. According to user’s needs, partial ice storage mode was used. The basic control parameters and operating schedules of the ice storage central air-conditioning system were summarized.2. The overall and detailed design of the ice storage central air-conditioning automatic control system was completed. The overall design clarified principles, objectives, and effects of the ice storage central air-conditioning automatic control system. The detailed design completed the platform options, I/O design and function modules design.3. The implementation and test of the ice storage air-conditioning automatic control system was completed. A communication framework and a database of automatic control system were set up. Software programming for host computer was finished.According to an actual running, the safety, reliability, and rationality of the automatic control system are proved. All of the indicators meet the design requirements, and economy and energy efficiency of the ice storage air-conditioning are presented.