Weak current College】 【fruits and cold storage of humidity and refrigeration system configuration.

<br> <br> Most fruits and vegetables recommended humidity is a relative humidity of 90% to 95%, and in the humidity reaches 85% are difficult, some cold storage master had to increase the humidification device to increase the humidity, often not .obvious. Take the box in the film bag method although reduces the fruit and vegetable dehydration, but slow down the speed of cooling products, increased small environment harmful gas accumulation of high concentration, it has caused a product longevity of shortening and preservation problems decline. .<br> In fact, through the configuration of the refrigeration system, or you can reach the increase and maintain the environmental effect of high humidity. <br> 1, evaporation temperature and relative humidity of relations within the library <br> Evaporator, also .known as the cooler. The refrigeration systems and cold to heat, reduce refrigerator temperature of refrigeration parts. In the refrigeration system operation, the evaporator surface temperature of evaporation temperature, evaporation temperature and the difference in temperature of the library (¡÷ t), .the greater the freezer temperature drop faster, in the same heat conditions, the need of the evaporator surface area (evaporation area). At the same time, increase the speed of the cooler can increase heat. <br> Then, increase ¡ .÷ t, reduce evaporation area, and to increase the air cooler fan speed can be the same size and storage capacity of cold storage in lowering the investment cost? The answer is Yes. At present, most of the cold store is designed to cater to .the investor's low cost requirements and improve profits, contractors do not consider the effect of keeping the cold store, simply increase the temperature and wind speed, reduced air cooler for evaporation area, leading to the investor when the storage of fruits and vegetables are exposed to .serious economic losses. <br> General cold storage ¡ .÷ t mostly 10 ¡ .æ, can be seen from table 1, the library appears in the relative humidity is 70%. If you want to place the library in relative humidity up to 90%, △ should 5 ¡ .æ t. This is because the higher the temperature, the air moisture condensation in the air cooler evaporation fin opportunities. At the same time, the wind makes the unit of time in the number of times the air contact fin increases, increases moisture condensation. .Therefore, under large temperature difference cold storage practice, you will find the cooler in the frosting is very fast, increased number of defrosting. <br> Therefore, large thermoelectric cooler of cold storage, using a large humidifier, library humidity is also very difficult .to reach above 90%. More air moisture is condensed into cream cooler water. <br> 2, increasing evaporation temperature configuration <br> In accordance with the requirements of the fruits, the temperature setting is certain, then, to reduce ¡ .÷ t is bound to increase evaporation temperature cooler. As for 0 ° c evaporation temperature refrigerator, should rise from-10 ° c to-5 ° c to ensure that the hangar to 90% relative humidity. <br> For a specific a demand .of cold storage, refrigeration capacity. While cooler at elevated temperature of evaporation heat will significantly decrease, in order to ensure that the needs of the chilling cold storage, you must increase the heat evaporation area. <br> It is understood that the 0 ° .c library temperature, evaporation temperature from-10 ° c (¡÷ t = 10 ° c) rise to-5 ° c (¡÷ t = 5 ℃), its evaporation area need to be doubled. For a compressor, evaporator temperature rise ., the cooling capacity will increase the cooling capacity in the same conditions, the evaporation temperature rise, the appropriate selection on the compressor reduces one model, in this context the appropriate investment would decrease. <br> 3, refrigeration equipment investment and analysis of the .effects of <br> The amount of the guarantee cold cold, increasing evaporation temperature, the need to intensify the cooler models, reducing the compressor model. Total investments are described below. <br> To 180m3, polyurethane panels for insulation of the library of .fruits and vegetables in the library, for example, the amount of storage, the Japanese stock quantity 40t 4t, demand cooling capacity as 13900w. <br> Programmes 1 to ¡ .÷ t = 10 ¡ .æ conditions configuration, R22 refrigerant, air-cooled condensing units, refrigeration cycle is-10/45 degrees centigrade. 70% relative humidity within a library. <br> Compressor configuration 4CC-9.2 cooling capacity 15220w, allowance 1.09. Unit price $ 17000 .. <br> Cooler heat exchanger configuration DD-80, 17997w, allowance 1.29. Cooler price $ 5200. <br> Programme 2 to ¡ .÷ t = 5 ℃ condition, R22 refrigerant is configured, air-cooled condensing units, refrigeration cycle is-5/45 degrees centigrade. Library of relative humidity of 90% <br> Compressor configuration 4DC-7.2 cooling capacity 15650w, allowance 1.13. .Unit price $ 14300. <br> Cooler heat exchanger configuration DD-160, 16435w, allowance 1.18. Price $ 10100 cooler. <br> Other installation, control costs the same, this does not mention them all here. <br> Comparison of .these two programmes can be found in scenario 1 cost more than $ 2200 programme 2 decrease. <br> However, if the relative humidity within the library for 90% of programme 2-programme 1 per month to reduce water loss 2% of the fruits .and vegetables, can reduce the weight loss 800kg to $ per kg of fruits and vegetables 2.5 calculations can reduce losses of $ 2000. If the quality of water loss caused decreased storage time and other factors, the indirect economic losses. At the same time, .programme 2 reduces the number of defrosting, also reduces electric defrost temperature fluctuations in consumption and Library increases compressor power, equipment operating costs will be more economical. <br> 4. conclusions <br> Increase of evaporation temperature mini-cold, although in the .initial investment has increased, however, in the preservation and energy-saving aspects of greater significance. From the above calculation results, 1-month run can be part of multiple investing savings. <br> For single room freezer storage capacity over 200t of refrigeration .equipment, increasing evaporation temperature of the programme while the corresponding increase in other investments, and the preservation of energy saving. <br> If the number of cold storage using parallel compressor refrigeration system, not only in the cold cold energy demand precise leveling on automatic ., achieve more energy-saving effect, at the same time because of the evaporative cooler, the amount of the purchase area increase or freezer to advance the use of cold storage, you can also adjust the evaporating temperature to meet has been significantly improved chilling cold .storageQuantity. <br> <br> <br> <br> <br> <br>.