1、动态冰蓄冷技术的研究进展（Research progress of dynamic ice storage technology）Research progress of dynamic ice storage technology http:/ 2009-1-19 review, 73 gas water direct change environmental protection refrigerantrecommendation the Fifth China (Tianjin) International Heating and ventilationrecommendation Si
2、xth Central China (Wuhan) refrigeration, air conditioning and warmrecommendation China (Jinan) international energy saving products and technologiesrecommended2009 Jilin (Changchun) second indoorrecommendation2009 second Northeast China energy saving and environmental protectionrecommendation the se
3、cond Jiangsu international energy saving heating, air conditioning andrecommendation the second China (Xian) International ground source heat pumprecommendation the Eleventh China (Xian) International Heating Supplyrecommendation2009 Dalian international energy conservation and environmental protect
4、ion technology andrecommendation2008 China Tianjin (International) refrigerationrecommended the sixth Guangzhou (International) air conditioning and coolingResearch progress of dynamic ice storage technologyAbstract: This paper introduces several common dynamic ice storage and new dynamic ice storag
5、e technology, discusses their respective advantages and existing problems, and looks forward to the future research directions.Keywords: ice storage; dynamic;0 IntroductionChinas demand for electricity is increasing, the peak of power supply is insufficient, and the contradiction between the surplus
6、 and the surplus is becoming increasingly prominent, which has seriously affected the economic development and peoples normal life. The reason is largely due to the operation of a large number of air conditioning units. According to statistics, air conditioning power consumption accounts for 60% to
7、70% of the total energy consumption of buildings, and air conditioning power accounts for more than 30% of the total urban power supply in large and medium cities. Therefore, as an important means of balancing power grid load and shifting peak load, cold storage air conditioning technology has been
8、paid more and more attention by people. 1. Because the water storage technology has become obsolete, the eutectic salt storage limit of 4 cold storage medium for high 23, gas hydrate cold storage by coolant conditions, application of ice storage technology occupy a dominant position, the national en
9、ergy policy document “2004 energy and long-term planning“ is also clearly stated: to develop ice storage technology. Compared with the mature static ice storage technology, the dynamic ice storage technology is less practical, so it needs further research and development.1 dynamic ice storage system
10、1.1 pieces of ice machineThe ice storage machine has fast cooling and cooling rate, and is less affected by the thickness of ice layer. (the effect of small piece ice is better). There are two main ways to make ice flake: mechanical scraping type and thermal melting sliding type. The “hot melt slip“
11、 type means that water from the ice storage tank is sprayed up and down on the surface of the plate evaporator through the water pump and frozen over thin ice layer. When the ice thickness reaches 5 10mm, through the valve reversing, the high temperature gaseous refrigerant from the compressor pass
12、into the evaporation plate heat, make contact with the surface evaporation plate of ice, ice by gravity down to the ice storage tank, high temperature gaseous refrigerant through the heat into a liquid or liquid gas mixture flows to the condenser. When cooling, the backwater can be sprayed on the ev
13、aporator by the pump and then contacted with ice or directly introduced into the ice storage tank to heat up with ice. So repeatedly “freeze“ and “release ice“ process, 5. The evaporation temperature of the method can be increased by 3 DEG C and the cooling rate is faster than the ice coil storage s
14、ystem, and is especially suitable for occasions requiring a large amount of cold in a short time in a gymnasium, a hall, a dining room, etc At present, only Zhejiang, Shanghai, Beijing, Jiaxing Monte Donghua University Zhongguancun Software Park, four pieces of ice cold storage project, there are a
15、number of under construction. The disadvantage of this method is that ice making requires larger space and ice content is too large. It may cause blockage of pipes or water filters, so the filling rate of ice storage tank is not high. Unlike the thermal sliding system, the mechanical scraping system
16、 uses mechanical scrapers instead of high temperature gaseous refrigerant to remove ice, so there is no need for valve control. However, the increase of the moving parts, the higher maintenance and management requirements, the initial investment and energy consumption are greater. Others are basical
17、ly the same as the thermal melt down system1.2 ice crystal machineIce crystals are tiny grains of ice and water mixture, the forming process is similar to the snow, since the crystal nucleus with three-dimensional outward growth to become a generation after the liquid ice slurry, can be transported
18、by the pump, so can also be called fluid ice, ice or ice slurry two yuan. Its significant advantage is the cooling speed, good fluidity, ice can be in one place, another ice storage; heat transfer coefficient of the ice making process, the compressor performance coefficient COP value can be greatly
19、improved than making ice; ice and ice melting rate. Therefore, ice crystal is an effective medium for air conditioning storage 6.1.2.1 ethylene glycol solution supercooled ice making systemThe system refers to the low concentration of ethylene glycol solution cold to below freezing point, and then i
20、nto the storage tank, the solution can be precipitated ice crystals. If the supercooling temperature is 2 DEG C, 2.5% ice crystals with a diameter of about 100 m can be produced 5. When cooled, ice crystals are sent directly to the air conditioning load end. The system requires a special ice maker a
21、nd a specially designed evaporator (ice crystal generator),The ice content of ice crystals is too high, which will lead to the increase of transmission resistance, so it is not suitable for large-scale systems. At present, Beijing low temperature equipment factory produces the equipment.1.2.2 superc
22、ooled water dynamic ice making systemThe system uses the supercooling of water to make ice. When cold storage occurs, the cold two refrigerant produced by the refrigeration compressor unit will lead to supercooling of the water in the super cooler, and the supercooled state will be removed at the ou
23、tlet of the cooler so that the ice crystals can be precipitated. The core component of the system is the over cooler. Japan has studied this technology for nearly 20 years, and also has some examples of engineering applications, but it is not yet mature. The main problem is that supercooled water is
24、 a very unstable state. It often freezes frequently in the chiller, resulting in reduced system efficiency and even blocked the line 7. Therefore, how to control supercooled water without freezing in the cooler is the key problem to be solved. The present approach involves adding some additives to t
25、he water to prevent water from freezing in the cooler, 8.2 new dynamic ice storage method2.1 water contact with immiscible liquid, heat transfer, ice making, cold storageSoutheast University Institute of thermal power engineering is put forward a new concept of 9 fluid ice: water immiscible liquid i
26、n low temperature atomized into fine droplets, and through the water immiscible liquid direct contact heat ice to replace water and solid wall heat transfer of ice. The non miscible liquid is called the carrier cold medium. It should have the following properties: 1, not miscible with water and free
27、zing point below 0; 2, it has good fluidity at the ice making temperature. This method refers to the load of cold medium flows through the evaporator is cooled to O DEG C, in the channel, through the nozzle submerged in cold carrier medium will be atomized into fine droplets and water sprayed into t
28、he downstream, the water and surrounding low temperature cold medium load direct contact heat transfer, in the process of flowing freeze into ice particles. The method is suitable for air conditioning and cold storage, and the thermodynamic efficiency of the system is high. But it is necessary to st
29、rengthen the atomization characteristics, solidification characteristics and heat transfer characteristics of multiphase mixing flow in immiscible liquid.2.2 oil-water emulsion dynamic ice storageAs shown in Figure 2, the system of cold storage is the oil and water mixture, adding additives in the c
30、ontainer, stirring to form a stable emulsion, a mixture of ice and into the heat exchanger cooling emulsion formation and ice, through the filter to filter out the ice crystals, filtering liquid into the original container to complete the cycle.Water emulsion ice making has not been reported in chin
31、a. Japanese scholars have been studying more recently. SaitO 10 and Grandum 11 was observed by scanning tunneling microscopy of the ice formation process of emulsion, found bis silane with adsorption in ice surface, can effectively inhibit the growth of ice crystals is too large, is a good ice makin
32、g technology in oil-water emulsifier.Oshinari Da 12 experimental study of the process container with the mixer cooling emulsion formation of ice crystals, found that adding double silane and reduce the critical surface tension of the container surface can inhibit ice adhesion on the surface of the c
33、ontainer, the liquidity remains oil-water mixture and prevent ice blockage of pipeline is very important.Kazutaka, Chibana, et al. 13 studied the ice formation process in a spiral polyvinyl chloride plastic (PVC) dish controlled ice heat exchanger, immersed in a two refrigerant. The ice crystal form
34、ation and the inlet and outlet temperature of the ice making heat exchanger were measured, and the heat transfer efficiency of the spiral coil heat exchanger was calculated. The influence of the thickness of coil, the flow of emulsified oil and the temperature of two refrigerant on the amount of ice
35、 and the speed of freezing is also analyzed. It is found that reducing the thickness of the coil can increase the temperature of the non freezing liquid and improve the COP value of the chiller, but the flow rate of the emulsified oil must be reduced, otherwise the ice making rate will be reduced.Yo
36、shinari Oda and Masashi Okada14 mixture of emulsified oil with 90% water, 10% further and aminopropyl - three ethylsilane form as the research object, the circular ice heat exchanger adopts PVC as the outer tube, PTFE is used as the inner pipe of the heat exchanger, the two refrigerant and the inner
37、 tube form a circular pipe through the outer tube the emulsion mixture flows through the inner tube. It is found that PVC can be used as outer tube and PTFE as inner tube. The ring heat exchanger has good heat transfer performance, and can achieve steady, continuous and dynamic ice making without cl
38、ogging. Compared with ethylene glycol solution, cold ice making is more efficient for oil and water emulsification and dynamic ice making, and further reduces the installed capacity.The ice surface evenly covered with a layer of oil film, increasing the flow of ice crystals, effectively prevent the
39、formation of ice blocking of pipeline wall bonded pipe, and ice crystals during storage are not sticky ice, cold heat release efficiency is very high and the discharging rate is very fast, is a worthy of attention the technology. However, the emulsion state has great influence on the ice making proc
40、ess. If the emulsion is not good or separated from each other, the pipeline will be blocked. Therefore, the stability of emulsified oil and good emulsification effect should be guaranteed.In addition, searching for cheaper and better emulsifiers to replace silane and reduce system cost is the resear
41、ch direction of 15.3 outlookAt present, the practical engineering of dynamic ice storage technology is still rare, and the dynamic ice storage technology will be more practical, which is the future direction of efforts, and develop more practical and efficient dynamic ice making method. In the slidi
42、ng vane ice machine, how to shorten ice fall space and increase ice filling rate (IPF) is a subject worthy of study. Because ice crystals can be transported by pump and large amount of heat is exchanged, it is a good medium for regional cooling. Therefore, the development of ice crystal storage tech
43、nology is promising. The heat transfer characteristics and transport characteristics of ice crystals will be further studied.Reference1 is bing Feng. The new central air conditioning technology and its application M. Beijing: Chemical Industry Press, 2005,1:261-306379-401.2, Li Xingren, et al. Exper
44、imental study of eutectic salt low temperature storage materials J. Journal of Chongqing University, 2004,27 (8): 113-115.3, G., Alane., PCM, Science, and, Technology, the, essential, connectionC., ASHRAE, Trans, HI-85-38, No41987-1997.4, Xie Yingming, Liang Deqing, Guo Kaihua, et al. Research status and Prospect of gas hydrate thermal storage technology J. HVAC, 2004,34 (9): 25-28.5 Ye Quan, Fang Feng. Ice storage air conditioning technology J. refrigeration, air conditioning and electric power machinery, 2004,25 (1): 72-79.
