Type selection analysis of the hottest ice storage

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Type selection analysis of ice storage system

I The development of ice storage technology in China

China's power industry has developed rapidly. In 1996, the installed power generation capacity has reached the second place in the world. By the end of 1997, the installed power generation capacity in China had reached 250million kW, and the annual power generation capacity was 1113.2 billion kw. However, with the development of economy and society, the contradiction between insufficient peak and excessive trough of power supply has become prominent. It is difficult to achieve all by building new power plants. The use of demand side regulation methods, such as ice storage of air conditioners, can move the power consumption time to non peak periods, playing the role of "shifting peak and filling valley"

at present, some regions in China have implemented peak valley electricity price policies, as shown in Table 1

II Problems needing attention in the application of ice storage

1 Ice storage operation strategy

it is divided into full cold storage and partial cold storage

full cold storage is to store the required cooling capacity during the low peak period of power use, so as to avoid the operation of the refrigerator during the peak period. This system operates in the non peak period at night. The refrigerant generated by the evaporator is supplied to the cold storage device, and the low-temperature cooling capacity is stored in the form of ice. At this time, the building air conditioning system does not operate. During the operation of the air conditioning system, the refrigerator does not operate. 100% of the required cooling capacity is provided by the melting of ice in the ice storage device. The operation cost of this type of system is the lowest, but the required refrigerator capacity and cold storage capacity are large, and the initial investment is large. We should only learn from the previous technical experience, which is suitable for occasions where the air conditioning time is relatively small, such as the milk cooling in gymnasiums, cinemas, office buildings and the food industry

compared with full cold storage, partial cold storage also provides a certain amount of cooling during air conditioning. Most ice storage systems adopt the form of partial cooling storage to reduce the initial investment, and the control of cooling load is more convenient

2. The project environment analysis

mainly examines the electricity price and water price, and whether the local power department has preferential policies for ice storage. In some regions where ice storage develops rapidly in China, the government often adopts some special policies, such as the third item of the notice of the Hangzhou three power office on the relevant provisions of the reward and allocation of power saving technological transformation in Hangzhou in 1997, ice storage air conditioning, when the cold storage capacity is greater than 1700 kWh (price difference), gives three additional concessions to relevant users in urban areas: (1) implement peak valley electricity price for ice storage central air conditioning users; (2) Ice storage central air conditioning equipment can be used without avoiding peak; (3) For the users of ice storage central air conditioning who are listed in the demonstration project of power saving technology and meet the above requirements, according to the comprehensive actual effect, the power expansion fee and air conditioning equipment capacity fee will be reduced and increased according to% of the host capacity of ice storage air conditioning

3. Master data

determining the optimal air conditioning cooling load on the cooperation day of the typical design through the detailed drawing of the building structure not only has the capital level, but also determines the temperature of the cold storage cooling water through the change of the ambient temperature on the typical design day, analyzes the law of the use and occupation of the building, determines the daily hourly air conditioning load distribution diagram, and calculates the matching capacity of the cooling host and the ice storage device. Obtain equipment performance data. Building restrictions, such as available space, installation structure requirements, etc

4. Determination of air conditioning storage refrigerator

the compressor of the refrigerator of the air conditioning cold storage system operates under both ice making and air conditioning conditions. The suction temperature (pressure) of the compressor changes greatly from ice making to air conditioning conditions, and the compression ratio of the selected compressor changes greatly. The required compressor should be variable pressure ratio and variable volume. Generally, screw compressor is more suitable. At present, in the past, it was mainly imported. In recent years, some well-known international air-conditioning companies have gradually brought relevant technical majors to China, and have been able to purchase the most advanced air-conditioning storage chillers from China, without having to import them from abroad

in addition, the control system of the refrigerator is also much more complex than that of a single air conditioner. Such as ice making time control function, unit full load operation during ice making, ice melting volume control, heat exchanger control, dual condition unit protection function, etc

5. Ice storage system products

over the years, domestic ice storage products have developed greatly. According to incomplete statistics, already "There are more than 300 projects that have built industrial parks as an important carrier of industrial development, but these are still quite limited in alleviating the domestic power shortage and playing the role of shifting peak load and filling valley. There are many factors that restrict the current distribution and development of ice storage products. The main factors analyzed are as follows:

· the participation of suppliers in the design process is less. The ice storage system is more complex than the conventional system, and the traditional method is that the design institute or installation company will provide different supplies The components and parts provided by the supplier can not be optimized, and the components and parts are provided by different suppliers. The matching and selection of various components are very complex, and the selection is prone to errors or conservative selection, resulting in high final cost and long design cycle

· product delivery is difficult to coordinate. The delivery place and delivery time are different, so it is difficult to coordinate

· high installation error rate and long project cycle. Components from multiple sources increase the installation time, are prone to errors and on-site accidents, and the on-site installation cost is very high, the project quality cannot be measured, and the project cycle is long. Especially the ice storage tank and automatic control system made on site are difficult to guarantee the quality

· difficult to debug and use. The environment and situation faced by the system are still very serious. Most of the components have not passed the factory matching test, and need to be debugged and matched on site. The cycle is long and the efficiency is low. Lack of complete system data, the system has no adaptive control system, and can not give full play to the function of ice storage

· complex maintenance management. The maintenance workload is heavy and difficult to manage. In case of quality problems, they will quarrel with each other

the above factors also cause the initial investment of customers to be very high. If the influence of power capacity increase fee is not considered, the investment recovery often takes years, and many customers often still decide to use conventional air conditioners

for this reason, Shanghai Benjia air conditioning system Co., Ltd. actively cooperates with international famous air conditioning companies to carefully develop integrated ice storage system products. The system product is composed of ice storage host, hydraulic control module and ice storage tank

Figure 1 cold storage operation process

our cold storage products have a complete variety and a wide range of cooling capacity, including air-cooled cold storage products and water-cooled cold storage products. The compressor adopts scroll, screw and piston types. It has a number of original technologies:

◆ modular energy storage tank with energy storage measurement device and strict heat and moisture insulation measures

◆ combined hydraulic control module. A large number of complex on-site assembly work is avoided, the workload of design and installation is small, and the use is convenient and reassuring

◆ in Figure 1, the chiller is arranged at the downstream of the energy storage tank, and the inlet and outlet water temperature of the standard air conditioning water is ℃, which is convenient and stable to adjust. For special needs, the minimum temperature of air conditioning water can reach 1 ℃

◆ the technology combined with heat recovery and water source heat pump further improves the use efficiency and product reliability

compared with similar products, this kind of products can significantly reduce the design, delivery, installation and commissioning time, improve product quality and have excellent cost performance, as shown in Figure 2

Figure 2 features of our cold storage products


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