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1. Cold storage cooling load estimation: The most basic conditions required to calculate the cooling capacity of cold storage: Cargo type ； Warehouse size (length * Width * high) ； Storage capacity, tons ； Purchase volume, tons/day ； Cooling time, hours ； Incoming temperature,℃ ； Shipping temperature, ℃. 2. Calculation of cold storage storage capacity: Cold storage tonnage calculation formula: G=∑Vlρsη/1000 where: G—cold storage tonnage (t) ； Vl—nominal volume of cold storage (m3) ； η—Volume utilization coefficient of cold storage ； ρs—density of cargo (kg/m3). 3. Cooling load calculation: Q1—heat flow of envelope structure (W) ； Q2—Cargo heat flow (W) ； Q3—Ventilation heat flow (W) ； Q4—Motor operating heat flow (W) ； Q5—Operating heat flow (W). 4. Warehouse load calculation: cooling capacity: Warehouse load calculation formula: QE＝Q1＋PQ2＋Q3＋Q4＋Q5 in the formula: QE—cold room cooling equipment load (W) ； P—cargo heat flow coefficient. The load coefficient P of the cooling room and freezing room should be 1.3, and that of other cold rooms should be 1. Warehouse load is an indicator for evaporator selection. 5. Mechanical load calculation: Refrigeration capacity, mechanical load calculation formula: QM=(n1ΣQ1+N2ΣQ2+N3ΣQ3+N4ΣQ4+N5ΣQ5)R in the formula: QM—Cooling room mechanical load (W) ； n1~5 - various heat flow calculation coefficients. When there is no obvious difference between low and peak seasons in production throughout the year, n1 should be taken as 1. Cold processing room and other cold rooms should be taken as 1 ； Coolant cold storage room should be 0.3-0.6 ； It is advisable to choose 0.5-0.8 for the frozen food refrigeration room. R is the cooling loss compensation coefficient of refrigeration devices and pipelines. Generally, it is 1.07 for direct cooling systems and 1.12 for indirect cooling systems. Mechanical load is the selection index of the unit 6. Cold storage cooling load estimation: According to experience, there are two situations according to the size of the cold storage.: Cooling load estimation of small cold storage (below 400m3) ； Estimation of cooling load of large cold storage (above 400m3). Cooling load estimation of small cold storage (below 400m3): Storage temperature is above 0℃, evaporation temperature is -10℃, 50~120W/m3 ； Storage temperature -18℃, evaporation temperature -28℃, 50～110W/m3 ； Storage temperature -25℃, evaporation temperature -33℃, 50～100W/m3 ； The storage temperature is -35℃, the evaporation temperature is -43℃, 1 ton covers an area of 7m2, and the cooling capacity is 5KW/ton. * sky ； The smaller the cold storage, the greater the cooling capacity per unit volume. Logistics warehouse: Purchase quantity: 10%/day. Cooling time: 18~24 hours. Incoming temperature: Medium temperature library 25℃/low temperature library -8℃. Shipping temperature: Medium temperature library 0 ℃ / low temperature library -18 ℃. The smaller the cold storage, the greater the cooling capacity per unit volume. Large cold storage cooling load estimation (above 400m3): 1. Storage temperature 0~4℃, evaporation temperature -10℃ ； 2. Storage temperature -18℃, evaporation temperature -28℃. 1. Storage temperature 0~4℃, evaporation temperature -10℃, default parameters are as follows:: Goods name: fruits and vegetables ； Storage capacity (tons): 0.3 * 0.55 * Storage volume m3 ； Purchase volume 8% ； Cooling time 24 hours ； Incoming temperature: 25 ℃ ； Shipping temperature: 2℃. :At the default parameters, the medium temperature library mechanical load: 25～40W/m3 ； Typical configuration: 4 cold storage rooms ； 90HP parallel unit with medium temperature warehouse 1000㎡ * 4.5m high. 2. Storage temperature -18℃, evaporation temperature -28℃, default parameters are as follows:: Goods name: frozen meat ； Storage capacity (tons): 0.4 * 0.55 * Storage volume m3 ； Purchase volume, 5% ； Cooling time 24 hours ； Incoming temperature: -8 ℃ ； Shipping temperature: -18℃. Under the default parameters, the mechanical load of the low-temperature warehouse is 18~35W/m3 ； Typical configuration: 4 cold storage rooms ； 90HP low temperature parallel unit with low temperature warehouse 1000㎡ * 4.5m high. At default parameters, the mechanical load of the cryogenic library: 18～35W/m3 ； Typical configuration: 4 cold storage screw machines + ECO ； 75HP low temperature parallel unit with low temperature warehouse 1000㎡ * 4.5m high. Storage temperature -18℃, storage temperature 0℃ ； Typical configuration: 4 cold storage rooms ； 90HP low temperature parallel unit with low temperature warehouse 1000㎡ * 4.5m high ； Low temperature compressor cooling capacity 1KW/HP ； The cooling capacity of the medium temperature compressor is 2KW/HP. 7. Precautions when selecting cold storage equipment: condenser: In the case of large fluctuations in working conditions, evaporative cooling ； Air cooler: The high-temperature warehouse uses low-temperature air coolers, heat exchangers, and expansion valves. ； compressor: Low temperature compressor pulls high temperature warehouse ； Heat defrost: Quick freezing warehouse ； water rinse cream: water temperature ； Floor antifreeze: Ventilation, exhaust steam heating glycol. 8. Things to note when designing non-standard cold storage: water: Three stages of water cooling - water freezing - ice cooling ； respiratory fever: mushroom library ； Fresh air: Operation room, grape warehouse ； Humidity in cold room: seed bank ； Fruits and vegetables cool quickly: Restocking and time ； Chestnuts refrigerated: sprinkle water ； Vermicelli cold storage: four sections ； water freezing: Mineral water, ice skating rink ； Cross-frozen. water: Three stages of water cooling - water freezing - ice cooling ； water cooling: 4.187KJ/Kg * ℃ ； water freezes: 334.94KJ/Kg ； ice cooling: 2.093KJ/Kg * ℃. Vermicelli cold storage: Four stages, 3 tons of wet powder produces 1 ton of dry powder ； first paragraph: 35℃ — 2℃, 2h ； Second paragraph: 2℃ — -4℃, 2h ； Paragraph 3: -4℃ — -10℃, 6h ； Paragraph 4: -10℃ — -14℃, 2h ； Wet powder 1 ton/h, 120HP piston parallel unit, top discharge pipe + air cooler. 9. Unit selection: 1. Single machine and single database ； 2. One machine with multiple libraries ； 3. The parallel unit has multiple cold storage rooms. 1. Single machine and single database: Unit cooling capacity = 1.1 × cold storage cooling capacity ； Total cooling capacity of the system: Affluence coefficient 1.1-1.15 should be considered. 2. One machine with multiple libraries: Unit cooling capacity = 1.07 × sum of cold storage cooling consumption ； Total cooling capacity of the system: Pipeline losses of 7% should be considered. 3. Parallel unit with multiple cold storage rooms: Unit cooling capacity = P × sum of cold storage cooling capacity ； Number of cold rooms P Number of compressors 112 20.92 30.853 40.83 60.754 100.74 Total cooling capacity of the system: The pipeline loss of 7% and the warehouse operation coefficient for the same period should be considered. 10. Air cooler selection: Necessary conditions for air cooler selection: 1. Refrigerant ； 2. Cold storage temperature ； 3. Heat exchange ； 4. Structural form of air cooler ； 5. Cold storage size and air supply distance ； 6. Defrost mode. Necessary conditions for air cooler selection: refrigerant: Different refrigerants have different heat transfer and pressure resistance. R404a has a larger heat transfer rate than R22, about 1%. Cold storage temperature: The lower the temperature of the cold storage, the smaller the heat transfer amount and the larger the distance between the sheets. heat exchange: Heat exchange rate of air cooler ≥ cooling capacity of cold storage * 1.3 (effect of frost) ； Nominal heat exchange: Heat transfer in the sample × actual coefficient ； Heat transfer under design conditions: Nominal heat transfer × correction coefficient ； Storage temperature correction coefficient: The lower the temperature of the cold storage, the smaller the heat transfer. Fin material correction coefficient: Material and thickness. Fin coating correction factor: Anti-corrosion coating reduces heat transfer ； Air volume correction coefficient: Special requirements require fan replacement. Cooler structure ceiling type: Commonly used in cold storage ； Ceiling type: Dual air outlet, four air outlet, air conditioning ； floor-standing: Quick freezing room, or duct refrigeration. Cold storage size, air supply distance, cold storage size, uniform blowing, and determine the number of air coolers. Calibrate air supply distance according to sample parameters: Choice of defrost method: 11. Aluminum exhaust pipe configuration: Aluminum row pipe structural performance parameters: D32 * 2 Aluminum tube, "single-shaped" two fins, 0.37㎡/m, 95W/㎡, 35W/m, heat transfer temperature difference 8~10℃. Tube spacing 120mm, (100mm, 140mm) ； The length of each group of aluminum row pipes is less than 150m, usually about 100m. 2 to 4 sets of aluminum exhaust pipes are equipped with one expansion valve. Aluminum row pipe for -18℃ warehouse, floor area: Aluminum row area=1: 2 ； The 0℃ warehouse is prone to dripping, so it is not suitable to use top discharge pipes. -18°C library, 20m * 15m * 5m, R22 water cooling unit ； The aluminum row area is 600㎡, the total length is 1622m, divided into 16 groups, each group is 101.4m, each 4 groups is equipped with 1 expansion valve, and the evaporation load is 15KW ； 4 expansion valves TEX5-2, or TGEX-8 equipped with 1 expansion valve for every 2 groups, evaporation load 7.5KW ； 8 expansion valves TEX2-06. 12. Condenser selection: 1. Air-cooled condenser, condensing temperature 45℃ ； 2. Water-cooled condenser, condensation temperature 40℃ ； 3. Evaporative condenser, condensing temperature 36°C. Unit heat dissipation calculation: water cooling oil cooling: Unit heat dissipation = cooling capacity under operating conditions + shaft power ； Siphon oil cooling: Unit heat dissipation = cooling capacity under operating conditions + shaft power + oil cooling load. 1. Air-cooled condenser Air-cooled condenser heat exchanger = unit heat dissipation × 1.15. Condensation temperature 45℃～54℃ ； The condensation temperature difference of the optional condenser for the medium temperature unit is 10K ； The condensation temperature difference of the optional condenser for the low-temperature unit is 8K ； When there is no noise requirement, it is recommended to use the 06P (1000rpm) condenser. When the customer requires low noise, use the 08P (750rpm). 2. Water-cooled condenser Water-cooled condenser heat exchanger = unit heat dissipation × 1.10. Condensation temperature 40℃ ； Cooling tower selection: Water-cooled condenser heat exchanger 1KW = 1.3 × cooling tower water volume 0.287 tons/h. 3. Evaporative cooling heat exchange heat of evaporative condenser = unit heat dissipation × 1.75 ； Condensation temperature 36℃. 13. Expansion valve selection: Commonly used expansion valves: External balanced thermal expansion valve ； Electronic expansion valve. Ordinary cold storage -40℃～+10℃, N series ； Quick freezing cold storage -60℃～-25℃, B series. 4 necessary conditions for choosing an expansion valve: 1. Refrigerant ； 2. Evaporation temperature ； 3. Condensation temperature ； 4. Evaporation load. Four factors for expansion valve selection: 1. Refrigerant (Danfoss) ； R22: X (e.g. TEX2, TEX5, TGEX) ； R404a/R507 : S (e.g. TES2, TES5, TGES) ； R134a: N ； R407C: Z. 2. Evaporation temperature for ordinary cold storage -40℃～+10℃, N series ； Quick freezing cold storage -60℃～-25℃, B series ； cold storage: The evaporation temperature is 10°C lower than the storage temperature, and quick freezing is 8℃ ； tube shell: (Dry type) evaporator, the evaporation temperature is 5°C lower than the outlet water temperature. 3. Condensation temperature evaporation condenser: 36 ℃ ； water cooled condenser: 40 ℃ ； air cooled condenser: 45 ℃ ； Economizer: Subcooling does not need to be considered. 4. Evaporation load: The evaporation load between the expansion valve and the temperature sensing bulb. General situation: One expansion valve is equipped with one air cooler or 2 to 4 row pipes. There are also the following situations: 1 expansion valve with 2 or more air coolers ； A large air cooler uses two or more expansion valves. Expansion valve selection example: Air cooler: Evaporation load = heat transfer under design conditions ； R22: 0°C warehouse air-cooled condenser, air cooler DD-28.0/140 ； 1. Refrigerant: R22 ； 2. Evaporation temperature: -10 ℃ ； 3. Condensation temperature: 45 ℃ ； 4. Evaporation load: 30.8KW ； Expansion valve TEX5-4, TGEX-11 (12.5) ； The expansion valve throttle flow is greater than the evaporation load. Air cooler: Evaporation load = heat exchanger R22 under design conditions: -18℃ water-cooled condenser, air cooler DD-28.0/140 ； 1. Refrigerant: R22 ； 2. Evaporation temperature: -28 ℃ ； 3. Condensation temperature: 40 ℃ ； 4. Evaporation load: 28KW ； Expansion valve TEX5-5, TGEX-20 ； The expansion valve throttle flow is greater than the evaporation load. Aluminum pipe: Evaporation load = heat transfer under design conditions ； R22: -18℃ evaporator cooling 120m * 3 sets of aluminum exhaust pipes 1. Refrigerant: R22 ； 2. Evaporation temperature: -28 ℃ ； 3. Condensation temperature: 36 ℃ ； 4. Evaporation load: 13.3KW (37W/m * 120m * 3) ； Expansion valve TEX5-2, TGEX-8 ； The expansion valve throttle flow is greater than the evaporation load. Expansion valve selection: TE2，TE5，TGE。 The temperature sensing bulb must be installed on the horizontal pipe at the outlet of the evaporator. Install it in the correct position according to the instruction manual according to the diameter of the return steam pipe. It must not be installed on vertical pipes and oil return bends. When installing the evaporator, be sure to consider leaving a horizontal return vapor pipe installation location for the temperature sensor package.