【 Weak current College 】 talk about energy saving in cold storage

Energy, for attention, is a global problem requiring urgent. Energy, because energy is the national economy, national defense, and other aspects of the Foundation, is also directly affect our "cialis" important issues of the construction process. Address, access to good energy's ideas should be development and savings and a two-pronged approach. For management purposes, what more appropriate measures to conserve energy, are worthy of study and Research Division. The authors present under cold storage, analysis and discussion in today's conditions, finding ways to save energy.
Cold storage is frozen food processing, storage and distribution of important facilities in occupies an important position in the national economy. Energy is the national economic construction of one of the basic conditions, saving energy is the national economic construction of long-term strategic approach. As power consumption, large freezer in the long term State system, there are a large number do not attach importance to energy management and waste of energy, as the energy market and the world of standards, in particular, China's accession to any enterprise must be the world best competitive market, in which case the enterprise product quality and cost will determine the survival of an enterprise, energy in cold storage product costs in occupies an important position, improve energy conservation work will increase the economic benefits of refrigeratory Enterprise play an important role. Therefore, analysis, study of cold storage industry refrigeration system power consumption, of the refrigeration system operation in the operation of the energy-saving measures and methods, to conserve energy, reduce cold storage company production costs, improve economic relevance
1. status quo
Cold storage is a consumption electric power larger departments, according to statistics, only commercial system of food refrigeration industry, total energy consumption equivalent to about 17.3 billion, accounting for dissipation of 1.8 per cent. If the power consumption, approx. 5.7 billion, accounting for electricity generated by 1.6 per cent. While the cold storage and refrigeration industry mainly in electricity sector (bit), therefore, for refrigeration industry, the energy of the core departments are cold. At present, according to incomplete statistics conversion, cold storage and refrigeration system energy consumption, each frozen carcasses a ton about the average power consumption 110 degrees (including power consumption targets up to 180 degrees, tons of low power consumption indicator also reached 70 degrees, tons); for the freezing of one ton refrigerated room cold storage, the average power consumption of frozen foods is 0.4 ° day (power indicator per tonne up to 1.4 degrees/day, low power consumption indicators per ton also 0.2 degrees/day); for the cooling of refrigeration refrigeration ton of food among the average power consumption 0.5 degrees that day (including power indicators have up to 1 degree, day, low power consumption also 0.3 degrees that day). It can be seen. In the cold and frozen food in the freezing of all kinds of energy consumption with the regions, enterprises, cold storage design and management level, and so different, there is a big difference, therefore, for refrigeration systems through technical and scientific management to achieve energy-saving purposes, have great potential, "Wu" is available.
2. ways to save energy
On the cold store has many ways to save energy, such as the combination use of architectural space, give full play to the multifunctional role; the rational use of equipment, strengthen scientific management, improve equipment utilization; selection of new processing technology, new equipment and high-tech, and so on.
Selection of new technology, 2.1 new equipment and new technologies for design solutions
2.1.1 reduce refrigerant evaporating temperature and cold temperature of warm when the temperature inside the warehouse at a certain time, as the evaporation temperature and the temperature difference of temperature in the Treasury will reduce evaporation temperature increase could be appropriate, at this point, if the condensing temperature remains the same, it means that the compressor refrigeration capacity, can also be said that given the same refrigerating capacity, can reduce energy consumption. According to estimation, when evaporation temperature decrease 1 ℃, the more power 3-4 per cent. In addition, reduce temperature to reduce warehouse storage of food consumption of the stem is extremely favorable. Because the small difference in value to the Treasury for a larger relative humidity, can slow the Treasury air heat load of Exchange, thus reducing the consumption of fresh food, dry, especially not the storage of food packaging, should adopt the small temperature difference.
2.1.2 depending on refrigerated food and different storage period, determine the appropriate storage temperature values for various groups of foods, especially meat class in low-temperature storage period of biochemical changes and the growth of bacteria Aeromonas low temperature and the extent to which the reproduction is suppressed, you can determine the optimal storage temperature, if not more than half a year of low-temperature storage, general use of the storage temperature is-18-15 ℃; more than half a year of storage should be used ≤-low temperature of 18 ° c; for a fat content of foods such as fatty fish more, to prevent the low-temperature oxidation of fat storage period, should be lower than-18 ° c storage temperature, it is best to-24 a-20 ° c temperature. It has taken a different storage temperatures, for certain foods, particularly in the case of short-period storage that is equivalent to the above analysis increases evaporation temperature refrigeration system, thus increasing the amount of refrigeration compressors.
2.1.3 freezing rooms equipped with double-speed or variable speed fan. Food in the freezing process, actually release the heat is not uniform heat process, while the corresponding on cooling equipment required cooling capacity is uneven. Food of the freezing process can be divided into three phases, the first phase is the cooling phase, the temperature is > 0 ℃ to 0 ~ C around; the second stage is the ice formation stage, the food temperature by 0 ~ C left and down to-5 ℃; the third stage is to freeze the cooling phase, food from-5 ° c to-15 ℃. From analysis, food freezing of three phases, the second phase of the required cooling capacity maximum, then freeze all the devices you want among all the work, and in the first two stages, since the unit time heat load less, may be appropriate to reduce the cooler air volume reduction of the wind speed, in order to achieve the purpose of saving power. If the freezing cold wind machine using only one speed, not adjustable, then it will affect the freezing process cycle air and indoor air speed adjustment. In order to increase power consumption.
2.1.4 reduce cold storage building envelope unit heat flow indicators in cold storage design, low temperature cold facade of the unit heat flux q generally use the left and right, if 11.63W willQ to to 6.9W/then for a level of 5000T ~ 10000T estimated low-temperature refrigerator, electric charges dropped 10 percent. Of course, the unit of heat flow indicators, means that envelope insulation layer to thicken, one-time investment costs increased, and the running cost of cold storage is often reduced in comparison, then, from the economic point of view or from the standpoint of technology management, reduce cold storage building envelope unit heat flow index or a reasonable cost.
2.1.5 use cold storage building space, give full play to the multifunctional role. Freezing room with Mong, low season, but also greater than the peak time of season. In low season doubles as a frozen to storage packaging forming foods. This will increase the efficiency and cost-effectiveness; reduced the envelope, and so many different types of damages, to a temperature of between neighboring cold storage; accelerated food freezing speed, time to make better food quality; can also be combined with the use of the cooler, the storage of special food requirements of ultra-low temperature environment.
2.2 strengthen scientific management according
Surveys can be found in many refrigeration enterprises, at present, the energy conservation management in a weak, Enterprise energy wasting more serious (State-owned enterprises is greater than the private enterprise or large enterprises greater than small and medium sized enterprises). To this end, through the strengthening of the scientific management of enterprises and the positive technological transformation, can save a lot of energy and improve enterprise considerable economic benefits.
2.2.1 guarantee good heat results in actual use of the management process, to ensure that the cooling water discharge, prevention measures, improve water quality, reduce heat exchanger fouling level to ensure the effectiveness of heat exchanger, reduce condensation pressure (condensing temperature) to conserve power. According to calculations, condensing temperature at 25 ° c a + ¡æ, when lower 1 ° c, could save power 3.2 percent.
2.2.2 put oil on a regular basis or in a timely manner, on air, make sure that the heat transfer areas of utilization. On heat transfer of a part, should pay attention to the tube wall of oil pollution, mainly the refrigerant in the refrigeration oil entrainment, if too much oil, heat transfer surface forming oil desert, thermal resistance increase, reduce the heat transfer coefficient. According to the relevant information, when the evaporator with 0.1mm thick film, in order to maintain the set temperature, evaporation temperature will drop 2.5 ℃, the power consumption increased ll per cent; when the condenser tube wall ·prevent 1.5mm, condensing temperature will rise more than the original temperature, power consumption 2.8 ¡æ 9.7%; when refrigeration system with no condensing gas, its partial pressure value reached 0.196Mpa, power consumption will increase by 18 per cent. Therefore, in the use of management, to keep the heat transfer equipment good heat transfer efficiency and make full use of the heat transfer area, to reduce the energy consumption of refrigeration.
2.2.3 elimination of energy consumption of all types, large, old equipment in compressor because of cold storage building and period selected device, model differ, due to the use of management level there is a difference, working long hours and the lack of necessary maintenance and other factors, the compressor refrigeration capacity cannot meet the design time of heat load, thus increasing the compressor working cycle, so the power consumption, and other indicators also will increase the cost of the operation, which, according to the actual parameters of the compressor, timely updating of refrigeration compressors. In theory, technical input to temporarily increase the cost, but in the long run, or economic perspective.
2.2.4 saving water cooling system uses water mainly condenser water; refrigeration compressor cylinder cooling water use water evaporator, cooler water flushing cream. Save water can reach the water savings, and reach save energy. In order to be able to better conserve water, water reuse, this not only saves water, can also play a better use of the various equipment, cold storage and refrigeration system can take cycle water supply, for example, condenser water use circulation water, which is equipped with cooling towers or evaporative condenser, the water consumption is only about 5 per cent; and then as refrigeration compressor cylinder cooling water use water, each machine water is generally 2-4T, h, cumulatively, water consumption is considerable; and if the use of the Treasury of cream cooler water, water temperature in this section is very low, it cited the reuse of the condenser, which reduces water loss, reach the purpose of reducing condensation pressure.
2.2.5 on warehouse cooling pipes to timely defrosting cream is a poor conductor of heat, Frost layer too thick, it will greatly reduce the heat transfer performance. When cooling pipe surface of frost layer thickness and the pipe wall thickness are the same. Frost resistance of some thermal resistance than 99 of steel tubes — 443 times bigger, when frost layer thickness > lOmm, its heat drops 30 percent above the visible effects of frost layer on the heat transfer is so large, so the pipe wall of frost after heat transfer coefficient for cooling capacity, decrease the reduction, in order to achieve the same effect, the electricity consumption of refrigeration. By determine, when measuring the temperature difference between inside and outside the wall to lO temperature ℃, the library-l8 ℃, pipe work after one month, its heat transfer coefficient K value only about 70 per cent of the original value, particularly in cooler of finned tubes, when the knot Frost layer, not only thermal resistance increases, and the air flow resistance also increased, serious it to no wind. To this end, to periodically will sweep the evaporator surface or flush cream frosting. In addition, the heat transfer surface rust, dust, bonded air will have higher heat resistance, causing the heat transfer coefficient. Refrigeration system of scientific management to achieve energy-saving aspects is very much, such as operating temperature, according to the Treasury of heat load leveling compressor start-up and shutdown; put an end to open the "Pacific car" and "big horse cart" will be available in order to maintain normal refrigeration system for liquid, preventing excessive back to cold superheat; cold cold-stored door to actively maintain strict control of its open several times and time, maintain good tightness.
2.3 restructuring refrigerated foods to created a new cold storage energy channels as production development and the improvement of living standards, the current market for frozen food in urgent need of reform, the restructuring of frozen foods as a cold store of energy brought basic conditions.
2.3.1 pork carcass segmentation eviscerate energy saving effect to divide the meat in the carcase, eviscerate change previously frozen and chilled carcasses. According to statistics presentedThe meat carcasses with segmentation, eviscerate, go to freeze after processing fatty fat storage, saving 50% of the energy consumption of frozen, refrigerated space saving 5O a 55 percent, energy-saving effect is obvious.
2.3.2 refrigerated meat packing of energy-saving effect of past frozen food packaging, because there are no direct impact on the frozen food in storage time of drying shrinkage loss and energy consumption. If the meat carcasses to packaging division, which will enable packaging of frozen food in the stem losses during storage is basically near zero, because food consumption is greatly reduced by dry, reduce the number of defrosting evaporator, compressor of invalid power down to the smallest degree, actually played a role in energy conservation.
2.3.3 according to market needs, there are plans to control the amount of meat, frozen meat into chilled meat, suit people eat nutritious diet, eat fresh new ideas. Chilled meat, not only in appearance, nutrition, and other quality aspects of conservation of the best quality, energy consumption is also only frozen meat of 40 percent, also played a role in energy conservation.