Center of Excellence for Green Building – A Building Automation Systems Test Bed
The experimental research on performance assessment of HVAC control strategies consumes a great deal of cost and labor; besides, the study objects are normally fixed. Meanwhile, no single building performance simulation tool offers sufficient capabilities and flexibilities to accommodate the ever increasing complexity and rapid innovations in control systems and technologies. Therefore, it is necessary to establish a new emulation environment for performance assessment of HVAC control strategies. The aim of the presented work is to develop a hardware-in-the-loop emulation test bed for performance assessment of HVAC control strategies and to analyze the main factors that have impacts on the emulation results, thus to provide some ideas and solutions for the development of better performance emulation test bed in the future.
In order to achieve this goal, the available methodologies and tools for assessment of HVAC control strategies are first investigated and the key points of hardware-in-the loop emulation test bed are studied in detail. Further, a prototypical office building model is developed and its HVAC system is designed according to the cooling and heating load of the building. Corresponding control strategies are also selected and specified for the HVAC system. Then the design scheme of a hardware-in-the-loop emulation test bed is described in the report, which is to develop a middleware based on OPC protocol for real-time communication between software and hardware. A series of technical problems occurs during the development of the test bed are discussed as well. Finally, two levels of control strategies for the prototypical HVAC system are emulated and evaluated both with the building energy simulation software TRNSYS and with the hardware-in-the-loop emulation test bed, and the impacting factors of the emulation results are also analyzed.
The study work shows that the hardware-in-the-loop emulation test bed which combines the strengths of software and hardware can be used to emulate HVAC control systems and evaluate corresponding control strategies, so as to provide feasible methodology and new emulation test bed for performance assessment of control system and strategy.