Ideas and measures to improve energy station energy efficiency and system energy efficiency-Part 5

System Efficiency Improvement Measures

1.  water quality treatment

Corrosion, scaling, and impurity problems caused by poor water quality bring safety risks to system operation, increase the thermal resistance of dirt, and reduce heat exchange efficiency. The system adopts a combination of physical and chemical water treatment methods, and is equipped with a water quality monitoring controller to detect water quality indicators online and transmit them to the controller. Physical water treatment adopts a hierarchical method. The inlet filter of the energy station equipment performs primary filtration of large particle size impurities, and a side filtering equipment is installed for fine filtration. The filtration precision of the side filter equipment is 100 μm. The integrated side filter equipment of the normal temperature cold water system has 14 filter units and a filter area of 3.36 m2. The integrated bypass filter equipment of the high-temperature cold water system is equipped with 7 filter units with a filter area of 1.68 m2. The bypass filtration method avoids the high-pressure drop consumption of a fine filter on the main pipe, ensuring water quality while achieving low resistance. In terms of chemical treatment, a two-way treatment method of scale inhibition and corrosion inhibition is adopted. The dosing device is equipped with double medicine boxes. The type and dosage of dosing are determined according to the results of online water quality testing.

2. Monitoring and measurement

When determining monitoring and measurement objects, focus on and grasp the actual operation conditions, use monitoring data to guide operations, and avoid "blind" operations. For example, flow meters are installed at the interfaces of a single host, boiler, cold storage tank, air-conditioning water and cooling water main pipes, and balance pipes. Some of the flow data are directly involved in the control as the input value of the system control. For example, the flow rate of a single host is used to adjust the frequency of the primary pump. Traffic data not directly involved in self-control is used to evaluate the operating status of the system. The flow rate is related to the hydraulic working conditions and thermal working conditions of the actual operation of the system. Reflected in the system energy consumption and heat exchange effect, mastering the total system flow and single equipment flow is helpful for operation diagnosis and corresponding optimization. In the same way, in addition to measuring the total cooling (heat) supply of the system, 2 secondary pump loops, 36 third-stage pump units, and 37 mixed water pump units also measure the cooling (heat) supply in stages. Power meters are installed separately on energy equipment to provide data for operating status and energy consumption diagnosis in each area.

3. Control Strategy

The formulation of the control strategy is based on the system construction idea, and the implementation of various energy-saving measures is mainly based on the following three aspects.

1) Prioritize the use of high-temperature cold sources on the premise of meeting the heat and moisture load treatment requirements.

Various types of air-conditioning terminals in service areas such as passenger arrival corridors give priority to radiation and other sensible heat terminals. For double-coil air handling units, when the air-conditioning load is reduced, priority is given to reducing the supply of normal temperature cold water to the secondary coil. The effect of the above end-side control logic on the source side is to utilize as many efficient high-temperature cold sources as possible, increase the proportion of high-temperature cold sources used throughout the year, and improve the overall energy efficiency of the cold source system.

2) Dynamically set parameters based on year-round operations.

Combined with climatic conditions and usage characteristics, the water supply temperature on the source side and the air supply temperature of the air handling unit are dynamically set according to the load demand. By predicting the hourly load throughout the day, the normal temperature cold water storage system is optimally controlled to maximize cooling release and minimize operating costs, and formulate operating strategies for main engine cooling and storage cooling.

3) Determine the optimal setting values of each link based on the overall energy saving goal of the system.

Taking the highest comprehensive energy efficiency of the cold and heat source system as the control target, and optimizing the cooling water temperature setting value, equipment operation quantity and combination based on the host's variable working condition performance data. Determine the optimal air conditioning water temperature setting value by comprehensively considering the total energy consumption of the computer room and terminals.

By Sammi