| It was reported that Chinese generation capacity reached 1.64 trillion kwh in January, 2003 and ranked second after the United States in the world. Building consumes much energy, which accounts for about a quarter, particularly for the large commercial building. The so-called building energy consumption primarily consumes in the HVAC (Heating, Ventilating and Air Conditioning) system. Improving the performance of envelope structure is the most effective strategies for building energy conservation. But improving HVAC system's configuration, management and operation mode plays an important role in the building energy conservation. Therefore, it is necessary to carry out HVAC system's optimization research for energy saving.HVAC system is a non-linear, multi-variable and big delay system. Its operation has a problem of "two low and one high" problem, that is to say cooling/heating source and the circulating pump have low rate of load, the system's operation efficiency is low but the energy consumption is high. To solve the problem, the author brings the equipment's high efficient operation into its optimization modeling and establishes the equipment's efficiency optimization model and then gives the efficiency optimization strategies. Variable frequency technology is increasingly mature, so variable flow for the air-conditioning is widely installed in all kinds of buildings. It makes people feel more comfort during working and living. It also meets the harsh production conditions of some industry. So far, many scholars studied the optimization of VWV (Variable Water Volume) air conditioning system. For pumps with VSD (Variable Speed Drive), the research is primarily about the discussion of VSD problem or qualitative analysis and experimental measurement on energy saving. And for the chiller's optimization problem, the optimal chiller load distribution is a hot research at present.The paper carried out a large number of theoretical and simulation research about the methods of modeling, solving and controlling strategies for the research of HVAC system efficiency optimization strategies. The research was achieved by analyzing the operational features and practical requirements of electricity equipment in water plant loop of HVAC system. Main researches are as follows.First, summarize and compare the load calculation method of HVAC system. The simulation with EnergyPlus was done for some building after contrasting various air conditioning load calculation software. The simulation results showed the real-time changes of air-conditioning load during one day. This will provide the basis for air-conditioning equipment selection and the research of optimization strategies.Second, apply VSD technique for primary-secondary pump then measure some datas of Flux-Head and Flux-Power when the pumps operate under the rated speed. These datas were curve fitted by applying the least square method. And the relationships of Flux-Head and Flux-Power were given. The high efficiency field of secondary pump was regarded as the constraint of its efficiency optimization model. The secondary pumps' efficiency optimization model was established in the paper.Third, analyze the relationship between the chiller's COP (Coefficient of Performance) and the PLR (Part Load Ratio). And the relationship was given by curve fitting. In order to make multiple chiller's overall COP value be optimal, that is, the operation of chillers is high efficient, the chillers' efficiency optimization model was established.Finally, solve the secondary pumps' efficiency optimization model and the chillers' efficiency optimization model. Then the secondary pumps' efficiency optimization strategies and the chillers' efficiency optimization strategies were given and the equipments' energy consumption was also given with these strategies. The effects of their energy saving are obvious.The article ended with a summary of the full text, pointed out the advantages and disadvantages of this paper, and put forward the issues which need solving in the future.
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