动态冰蓄冷技术的研究进展（Research progress of dynamic ice storage technology）

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 2009-1-19 review, 73 gas water direct change environmental protection refrigerantrecommendation the Fifth China (Tianjin) International Heating and ventilationrecommendation Sixth Cen

2、tral China (Wuhan) refrigeration, air conditioning and warmrecommendation China (Ji'nan) international energy saving products and technologiesrecommended2009 Jilin (Changchun) second indoorrecommendation2009 second Northeast China energy saving and environmental protectionrecommendation the seco

3、nd Jiangsu international energy saving heating, air conditioning andrecommendation the second China (Xi'an) International ground source heat pumprecommendation the Eleventh China (Xi'an) International Heating Supplyrecommendation2009 Dalian international energy conservation and environmental

4、 protection 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 ic

5、e storage technology, discusses their respective advantages and existing problems, and looks forward to the future research directions.Keywords: ice storage; dynamic;0 IntroductionChina's demand for electricity is increasing, the peak of power supply is insufficient, and the contradiction betwee

6、n the surplus and the surplus is becoming increasingly prominent, which has seriously affected the economic development and people's 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 ac

7、counts for 60% to 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 te

8、chnology has been 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 positio

9、n, the national energy 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.

10、1 dynamic ice storage system1.1 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 slidi

11、ng type. The "hot melt slip" 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

12、 refrigerant from the compressor pass 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,

13、the backwater can be sprayed on the evaporator 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

14、and the cooling rate is faster than the ice coil storage system, 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

15、Park, four pieces of ice cold storage project, there are a 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

16、 the thermal sliding system, the mechanical scraping system 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 invest

17、ment and energy consumption are greater. Others are basically 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

18、generation after the liquid ice slurry, can be transported 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 c

19、ompressor performance coefficient COP value can be greatly 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 ethyle

20、ne glycol solution cold to below freezing point, and then into 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 condi

21、tioning load end. The system requires a special ice maker and 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 temper

22、ature equipment factory produces the equipment.1.2.2 supercooled 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

23、cooler, and the supercooled state will be removed at the outlet 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 no

24、t yet mature. The main problem is that supercooled water is 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 solve

25、d. The present approach involves adding some additives to the 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 forw

26、ard a new concept of 9 fluid ice: water immiscible liquid in 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 th

27、e following properties: 1, not miscible with water and freezing 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 w

28、ill be atomized into fine droplets and water sprayed into the 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

29、efficiency of the system is high. But it is necessary to strengthen 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 stor

30、age is the oil and water mixture, adding additives in the container, 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 cy

31、cle.Water emulsion ice making has not been reported in china. 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 t

32、he growth of ice crystals is too large, is a good ice making 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 contain

33、er surface can inhibit ice adhesion on the surface of the container, 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 exc

34、hanger, immersed in a two refrigerant. The ice crystal formation 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

35、and the temperature of two refrigerant on the amount of ice 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 b

36、e reduced, otherwise the ice making rate will be reduced.Yoshinari 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 pi

37、pe of the heat exchanger, the two refrigerant and the inner 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 a

38、chieve steady, continuous and dynamic ice making without clogging. 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, in

39、creasing the flow of ice crystals, effectively prevent the 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, th

40、e emulsion state has great influence on the ice making process. 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 research direction of 15.3 outlookAt present, the practical engineering of dynamic ice s