Whatever Type of Cold Room,
TopChiller Can Fulfill the Cold Room for You.
- Room temperature from 10℃ to -35℃: TopChiller will design and make the cold room based on your required temperature.
- Both air cooled chiller and water cooled chiller: TopChiller have air cooled chiller and water cooled chiller for option.
- Over 20 years experience in cold rooms: TopChiller specialized in cold room and cold storage project with rich experience.
- Free design and drawing: TopChiller provide cold room design and drawing for you with free of charge.
- Onsite installation and commission: TopChiller having professional worker team can give onsite installation and commission service
- 18 months warranty time: Once purchased TopChiller cold storage product, We give 18 months warranty time
Cold Room: Your Premier Choice
Of Cold Storage Room Supplier
TopChiller is dedicated to supplying the finest quality cold room solutions to clients worldwide where they can store meat, vegetables, fruits, dairy, drinking, medicine, chemical, etc.
Our cold storage room and cold room refrigeration units are widely used in hotels, hospitals, blood banks, poultry slaughter processing, aquaculture processing, mushroom cultivation, agricultural product processing, dairy, production, pharmaceutical processing, etc.
TopChiller has over 20 years’ experience in designing and manufacturing cold rooms. Our innovative, high-quality products and solutions include cold room, freezer room, unit cooler, condensing unit, cold room door, PU panel, etc.
Cold room product from TopChiller has the following features:
- Dimensions: Depends on your storage capacity. From 500kg to 500T are available.
- Room Temp.: -30°C to 10°C
- Refrigerant: R404a
- The thickness of panel: Depends on your requirements
- Chiller Refrigeration unit: According to the temperature and the dimensions
- Door: Swing door or sliding door and the bi-fold door is optional
- Can be used in food, agriculture products, milk, beverage cold storage
- Both air-cooled chiller and water cooled chiller with the cooling tower are available
- Technical Documents: Complete documents such as instruction, operation manual, wire diagram, good list, and certification.
As a professional cold room and cold storage project manufacturer, TopChiller would like to provide all turkey project and all onsite service.
TopChiller has exported and installed many cold room projects in the Philippines, Australia, New Zealand, Malaysia, Singapore, Indonesia, Chile, Mexico, Costa Rica, Brazil, Argentina, Colombia, South Africa, Nigeria, Saudi Arabia, Dubai, Spain, Italy, etc.
If you have any inquiry regarding cold storage or refrigeration warehouse, please contact TopChiller to get an instant quotation.
TopChiller: Your Reliable Cold Room Manufacturer
TopChiller is a professional cold room machine supplier in China. We have served dozens of cold storage projects in more than 5 countries.
- Installation and commissioning of cold storage refrigeration equipment
- Why should the cold storage be defrosted? How many do you know about defrosting in a cold room?
- 10 kinds of cold storage room common fault problems and solutions
- Determining the Price Factor of A Cold Storage Room
- How to maintain and repair your cold storage room
- Why TopChiller can be your reliable cold storage room supplier?
- Some commonly used refrigeration unit
The main equipment and materials of cold room projects are as below:
Refrigeration chiller system: Compressor brand are Copeland, Danfoss, and Bitzer
Condensing units: Air-cooled type condenser Evaporator, Air cooler.
Refrigerant: R22 or R404a is available.
Electrical parts: Schneider brand from France
PU Insulation panel, cold store panels:
Raw material: polyurethane (PU), metal sheet.
The density of PU: 35~42kg/m3.
Metal sheet: According to requirements.
Thickness of panel: 50mm,75mm,100mm,120mm,150mm,200mm are all available.
Cold store door, air curtain machine, lighting sliding door, manual opening, and closing. When the door is opened, the air curtain machine and lights in cold storage can be running automatically.
TopChiller has a 12 months warranty time for all the cold room chiller machine or refrigeration system, and cold room wall materials.
TopChiller is willing to provide high quality and turnkey cold room project worldwide.
TopChiller has a team of 10 engineers who can provide door to door service including onsite installation and commissioning of the cold room projects.
The compressor is the most core part for a chiller and cold room refrigeration unit. But how to select the right compressor type and model for your cold room project?
According to the structure, cold storage refrigeration compressors can be divided into two categories: hermetic scroll compressors and semi-hermetic piston refrigeration compressors.
At present, the market is mainly semi-closed piston refrigeration compressors (the amount of screw compressors is increasing). Semi-closed piston refrigeration compressors are generally driven by four-pole motors.
The rated power is generally between 60-600 KW and the number of cylinders is 2. — 8 , up to 12 . The fully enclosed refrigeration compressor and the motor used together have a main shaft housed in the casing, so that the shaft sealing device can be eliminated, reducing the possibility of leakage.
Below we look at their advantages and disadvantages.
Advantages: The refrigeration compressor and the motor are housed in a casing welded by welding or brazing, sharing the main shaft, which eliminates the shaft sealing device and greatly reduces and reduces the size and weight of the entire compressor.
Only the exhaust pipe, process pipe and other (such as spray pipe) necessary pipes, input power terminals and compressor brackets are welded to the outer surface of the casing.
Disadvantages: Since the entire refrigeration compressor motor unit is installed in a sealed casing that cannot be disassembled, it is difficult to open for internal repair.
Therefore, the refrigeration compressor is required to have high reliability and long life, and the installation of the entire refrigeration system.
The requirements are also high. This fully enclosed structure is generally used in small-volume refrigeration compressors for mass production.
The semi-hermetic refrigeration compressor mostly adopts the cylinder block-crank box overall structure, and the motor casing is often the extension part of the cylinder crankcase to reduce the connection surface and ensure the concentricity between the compressor stage motors.
The two spaces of the crankcase and the motor compartment are communicated by the holes to facilitate the return of the lubricating oil.
The main shaft of the semi-hermetic refrigeration compressor is a structure of a crankshaft or an eccentric shaft; the built-in motor is cooled by air or water, and some are used to suck low-temperature working fluid vapor. For semi-hermetic compressors in the low power range, the lubrication is often done by centrifugal oil supply.
Widely used in cold storage, refrigerated transport, refrigeration processing, showcases and kitchen refrigerators.
Advantages of using a semi-closed refrigeration compressor:
It can adapt to a wide range of pressure and cooling capacity; high thermal efficiency, less power consumption per unit, especially the presence of gas valve makes it more obvious when running away from design conditions.
The requirements are low, and the common steel materials are used. The processing is relatively easy and the cost is relatively low.
The technology is relatively mature, and the production and use have accumulated rich experience; the device system is relatively simple.
Installation and commissioning of cold storage refrigeration equipment：
A. Assembly and installation of the refrigeration unit
1. The oil separator should be installed in the semi-sealed or fully enclosed compressor, and an appropriate amount of oil should be added to the oil.
When the evaporation temperature is lower than -15 degrees, a gas-liquid separator should be installed and an appropriate amount of refrigeration oil should be installed.
2. The base of the compressor should be equipped with a damping rubber seat.
3, the installation of the unit should have maintenance space, easy to observe the adjustment of the instrument and valve.
4. The high-pressure gauge should be installed at the three-way of the liquid storage valve.
5. The overall layout of the unit is reasonable and the colors are consistent. The installation structure of each type of unit should be consistent.
B. Cold storage and air cooler/ refrigeration chiller installation
1. When selecting the position of the lifting point, first consider the best position of the air circulation, and secondly consider the direction of the structure of the storage body.
2. The gap between the chiller and the slab should be greater than the thickness of the chiller.
3. All the slings of the chiller should be tightened, and the bolts and slings should be perforated with a sealant to prevent cold bridge and air leakage.
4. When the ceiling fan is too heavy, use the No. 4 or No. 5 angle iron as the lintel. The lintel should span across the other roof and wall panels to reduce the load.
C. Refrigeration pipe installation technology
1. The selection of the diameter of the copper pipe should be in accordance with the pipe diameter of the compressor suction and exhaust valve. When the condenser is separated from the compressor by more than 3 meters, the pipe diameter should be increased.
2. The suction surface of the condenser and the wall are kept at a distance of more than 400mm, and the air outlet and the obstacle are kept at a distance of more than 3 meters.
3. The diameter of the inlet and outlet of the liquid storage tank shall be based on the exhaust and discharge diameters indicated on the unit sample.
4. The compressor suction line and the air cooler return line shall not be smaller than the size indicated in the sample to reduce the internal resistance of the evaporation line.
5. The exhaust pipe and the return pipe should have a certain slope.
When the condenser position is higher than the compressor, the exhaust pipe should be inclined to the condenser and a liquid ring should be installed at the compressor exhaust port to prevent the gas from cooling and liquefying after shutdown.
At the high pressure exhaust port, the liquid is compressed when the machine is started again.
6. U-bend should be installed at the exit of the return pipe of the air-cooling fan.
The return air pipe should be inclined to the direction of the compressor to ensure smooth oil return.
7. The expansion valve should be installed as close as possible to the cooling fan.
The solenoid valve should be installed horizontally, the valve body should be vertical and the direction of the liquid should be noted.
8. If necessary, install a filter on the compressor return line to prevent dirt in the system from entering the compressor and remove moisture from the system.
9. Before the sodium and lock nut of the refrigeration system are tightened, the lubricating oil should be wiped to lubricate, and the sealing property should be strengthened. After tightening, wipe it clean and the roots of each cutting door should be locked.
10. The temperature sensor of the expansion valve is fastened with a metal card at the outlet of the evaporator at 100mm-200mm and is tightly wrapped with double insulation.
11. After the whole system is welded, the airtightness test is carried out, and the high-pressure end is filled with nitrogen 1.8MP. The low-pressure end is filled with nitrogen 1.2MP.
The soap is leaked during the pressure-filling. The welds, flanges and valves are carefully inspected. After the leak is completed, the pressure is kept for 24 hours without pressure drop.
D. Electronic control system installation technology
1. Each contact marks the line number for maintenance.
2. Produce an electric control box in strict accordance with the requirements of the drawings, and connect the electricity to do the no-load test.
3. Name each contactor.
4. Fix the wires of each electrical component with the binding wire.
5. electrical contacts press the wire connector, the motor main line connector, the application line card is tight.
6. The connecting pipes of each equipment should be laid and fixed with clamps. When the PVC pipes are connected, they are glued and the nozzles are sealed with tape.
7. The distribution box is installed horizontally and horizontally, and the ambient lighting is good. The inside of the house is dry and easy to observe and operate.
8. The area occupied by the wire in the wire pipe shall not exceed 50%.
9. The selection of the wire must have a safety factor. When the unit is running or defrosting, the temperature of the wire should not exceed 4 degrees.
10, the wire should not be exposed to the open air, so as to avoid long-term sun and wind blowing wire aging, short circuit leakage and other phenomena.
E. Refrigeration system fluoride adjustment
1. Measure the power supply voltage. Measure the resistance of the three windings of the compressor and the insulation of the motor.
2. Check the opening and closing of each valve of the refrigeration system.
3. After evacuating, inject the refrigerant into the liquid storage to 70%-80% of the standard filling amount, and then run the compressor from low pressure to sufficient amount.
4. After starting the chiller machine, first listen to whether the sound of the compressor is normal, whether the condenser or the cooling fan is running normally, and whether the three-phase current of the compressor is stable.
5. After normal cooling, check all parts of the refrigeration system, exhaust pressure, suction pressure, exhaust temperature, suction temperature, motor temperature, crankcase temperature, temperature before expansion valve, observe frosting of evaporator and expansion valve, Observe the oil level and color change of the oil mirror, and whether the sound of the equipment is abnormal.
6. Set the temperature parameter and the expansion valve opening degree according to the frosting and usage of the cold storage.
F. Precautions during the test running
1. Check whether the valves in the refrigeration system are in the normally open state, especially the exhaust shut-off valve. Do not close.
2. Open the cooling water valve of the condenser. If it is an air-cooled condenser, turn on the fan and check that the steering water volume and air volume should meet the requirements.
3. The electrical control circuit should be tested separately beforehand. Before starting, pay attention to whether the power supply voltage is normal.
4. Whether the oil level of the compressor crankcase is in the normal position, generally should be kept at the horizontal centerline position of the oil sight glass.
5. Start the cooling compressor and check whether it is normal and the rotation direction is correct.
6. When the compressor starts, check the indication values of the high and low pressure gauges, whether they are within the pressure range of the normal operation of the compressor.
7. View the indication value of the oil pressure gauge, the compressor with the energy unloading device, the oil pressure indication value should be 0.15-0.3 MPa higher than the suction pressure, and the compressor without the unloading device, the oil pressure indication value is higher than the suction pressure by 0.05. -0.15MPa, otherwise the oil pressure should be adjusted.
8. Listen to the expansion valve for refrigerant flow and observe whether the pipeline after the expansion valve has normal condensation (air conditioning) and frost (cold storage).
9. Compressor with energy unloading should work at full load at the beginning of the operation. This can be understood according to the temperature of the cylinder head.
The cylinder head temperature is high, the cylinder is working, and the cylinder head temperature is low, the cylinder has been unloaded. When the unloading test is carried out, the motor current should be significantly reduced.
10. Safety protection devices installed in the refrigeration system, such as high and low pressure relays, oil pressure.
Differential relays, cooling water and chilled water shut-off relays, chilled water freeze protection relays, safety valves and other equipment should be identified during commissioning to avoid malfunction or malfunction.
11. Check whether other various instrument indication values are within the specified range. If abnormal conditions occur, stop the inspection immediately.
12. Common faults during refrigeration system commissioning are plugging of expansion valves or dry filters (especially medium and small Freon refrigeration units).
13. The main reason for the blockage is that the garbage and moisture in the system are not cleaned, or the water content of the added Freon refrigerant does not meet the standard.
The above information is all concerned about how to install the cold room cooler and refrigeration chiller, the coming items are for the installation of cold storage panels:
The cold storage involves a lot of technical skills in the installation process, masters the operation skills, saves time and effort, and has a beautiful appearance and practicality after the cold storage installation.
Cold storage installation techniques involve cold storage board installation techniques, cold storage door installation techniques, and refrigeration equipment installation techniques.
Cold storage installation skills, the first installation order cannot be reversed, it is difficult to install correctly after the installation order is reversed.
The installation order of the cold storage boards should follow the following principles:
If there is a cold storage floor, the cold storage floor should be installed first, then the sidewall station board, the rear wall station board, and the front wall station board should be installed, and finally, the cold storage roof board should be installed.
At the time of installation, the general cold storage door manufacturer will have a sequence number. It is best not to disturb the order of the manufacturers.
In order, the joints of the cold storage plates and the convex and concave joints are tightly started to lock the buckles.
It is easy and natural after the library is built, Use a cold storage special sealant to seal the seam between each cold storage plate.
Cold storage door installation skills: The first thing to pay attention to in the cold storage door installation is the balance of the door frame.
Many small cold storage engineering companies do not pay attention to the balance of the door frame when installing the cold storage door.
After the installation is completed, it is found that the cold storage door is inclined, not inclined toward the inner side, or inclined toward the outer side.
The inclination of the cold storage door directly affects the insulation effect in the cold storage.
Specific operation method:
1. Leave the vertical ridges on the left and right door frames on the height of the frame on the door.
1. Fix the door frame after using the horizontal balance door frame;
2. The upper frame plate of the cold storage door is pushed into the installation position from bottom to top;
3. Push the frame on the door of the partition wall and push it from bottom to top into the installation position.
Second, the heating wire and the door frame strip device.
1. Adhered to the door frame by aluminum foil tape. The door frame strip is riveted to the door frame, and the cold storage library door heating wire is arranged around the outside of the opening 25 mm. Cover the heating wire.
Third, the device of the revolving door.
1. The template will be installed (MB1 left end hinge device template, MB2 right end hinge device module,
2. The screw holes of the device for prefabricating the hinge and the door lock on the door panel. Drill the tapping wire on the left and right door frames according to the positioning holes on the template.
Refrigeration equipment installation tips:
The important point of installation of the refrigeration equipment is to fix the equipment firmly. The first time the equipment is fixed is very important.
If the first time is not fixed properly, it will bring looseness to the operation of the equipment in the future, and the refrigeration equipment will be loose. Will accelerate the life of the device.
The installation of the refrigeration equipment must first select the distance between the external unit and the internal unit.
The closer the distance is, the better the cooling effect will be.
Choose the best inside and outside machine installation points, and the outside machine needs to be well covered.
The layout of the cold storage is carried out in a prefabricated manner, and the storage body components including the moisture-proof layer and the heat-insulating layer are made to be assembled on site, and the strength is that the construction is convenient, rapid, and movable, but the cost is relatively high.
Why should the cold storage be defrosted? How many do you know about defrosting in a cold room?
Due to the frost on the surface of the evaporator in the cold storage, the cooling and conduction of the cooling evaporator (pipe) are hindered, which ultimately affects the cooling effect.
When the thickness of the frost layer (ice layer) on the surface of the evaporator reaches a certain level, the refrigeration efficiency even drops below 30%, resulting in a large waste of electric energy and shortening the service life of the refrigeration system.
Therefore, it is necessary to perform the cold storage defrosting operation in an appropriate cycle.
The purpose of defrosting:
1. Improve system cooling efficiency;
2. Guarantee the quality of frozen products in the warehouse;
3. Saving energy;
4. Extend the service life of the cold storage system.
Cold storage defrosting method: hot gas defrosting (hot fluorine defrosting, hot ammonia defrosting), water spray defrosting, electrical defrosting, mechanical (manual) defrosting, etc.
1. Hot air defrosting – suitable for large, medium and small cold storage pipe defrosting:
The hot high-temperature gaseous condensing agent is directly discharged into the evaporator without being intercepted, and the temperature of the evaporator rises, causing the frosting layer and the cold-discharge junction to melt or subsequently peel off.
Hot air melting is economical and reliable, easy to maintain and manage, and its investment and construction are not difficult.
2, water spray defrost – mostly used in large and medium-sized air cooler defrosting:
Regularly spray the evaporator with normal temperature water to melt the frost layer. Although the defrosting effect of the water spray defrosting is very good, it is more suitable for the air cooler, and it is difficult to operate for the evaporation coil.
It is also possible to spray the evaporator with a solution with a higher freezing point temperature, such as 5% to 8% concentrated brine, to prevent frost formation.
3, electric heating defrost – an electric heating tube is mostly used for medium and small air coolers:
The electric heating wire is mostly used for medium and small cold storage aluminum tube electric heating defrosting, which is simple and easy to use for the cold air blower, and convenient to use; but for the case of the aluminum tube cold storage, the construction of the aluminum fin mounting electric heating wire is not small.
And the failure rate in the future is also relatively high, the maintenance management is difficult, the economy is also poor, and the safety factor is relatively low.
4, mechanical manual defrost – small cold storage tube defrost application:
Cold depot pipe manual defrost is economical, the most primitive defrost method. Larger cold storage is not realistic with artificial defrosting.
It is difficult to operate upwards, and physical energy consumption is too fast.
The long stay in the library is too long to be harmful to the health of the body.
Defrost is not easy to completely remove, which may cause deformation of the evaporator and may even smash evaporation. The refrigerant caused a refrigerant leakage accident.
Fourth, the fluorine system defrosting mode selection:
A relatively suitable defrosting method is selected depending on the evaporator of the cold storage. A few micro-miniature cold storages use a parking garage to open the door, using air heat to naturally defrosting.
Some high-temperature storage chillers choose to stop the chiller, open the chiller fan separately, use the fan to circulate air to defrost, and do not activate the electric heating tube to achieve energy saving.
1. Defrost mode of air cooler:
(1), there are electric heating tube defrosting and water rushing cream can be selected, the area where water is more convenient can be biased to choose water blasting chiller, and the water shortage area is biased to choose chiller of electric heating tube defrosting.
(2), electric heating tube defrosting is mostly used in small air cooler defrosting; water blasting cold air fan is generally deployed in large air conditioning, refrigeration systems.
2, the steel defrosting method: there is hot fluoride defrosting and manual defrosting can choose.
3, the defrost mode of aluminum tube: there are hot fluoride defrost and electric heating cream can choose.
Five, cold storage defrosting time:
Most cold storage defrosting is now controlled based on the defrosting temperature probe or defrosting time.
The number of defrosting times, the time, and the defrosting stop temperature should be adjusted according to the quantity of the stacked goods and the quality of the goods.
At the end of the defrosting time, and then to the dripping time, the fan starts again.
Note that the defrosting time should not be set too long, try to achieve a reasonable defrosting. (The defrosting cycle is generally based on the power transmission time or the compressor startup time.)
Six, the cause of excessive frost:
There are many reasons that affect frost formation, such as evaporator structure, atmospheric environment (temperature, humidity), and airflow rate. The effect on frost formation and air cooler performance is as follows:
1. The temperature difference between the inlet air and the cold storage cooler;
2. The humidity of the inhaled air;
3. Fin spacing;
4. Import air flow rate.
TopChiller suggests that when the temperature of the reservoir is higher than 8 °C, the normal cold storage system is almost no frost; when the ambient temperature is -5 ° C to 3 ° C。
The relative humidity of the air is large, the air cooler is easy to frost; when the ambient temperature is decreasing As the moisture content in the air decreases, the frosting rate decreases.
Once your cold room or cold storage finished the installation and on running, but the cold storage temperature is not good, check these problems first:
In the refrigeration system of cold storage, the most common operational failures are: slow cooling temperature, abnormal system operation, or inoperable operation.
The cold storage refrigeration temperature drops slowly, mostly due to improper operation adjustment, and the adjustment of the expansion valve is the most critical.
The opening degree of the expansion valve is small, the flow rate of the refrigerant is small, and the pressure is low; the opening degree of the expansion valve is large, the flow rate of the refrigerant is high, and the pressure is high.
Depending on the thermal properties of the refrigerant, the lower the pressure, the lower the corresponding temperature; the higher the pressure, the higher the corresponding temperature.
According to this law, if the expansion valve outlet pressure is too low, the corresponding evaporation pressure and temperature are too low.
However, due to the decrease in the flow rate into the evaporator, the pressure is reduced, the evaporation rate is slowed down, the cooling capacity per unit volume (time) is decreased, and the cooling efficiency is lowered.
If the expansion valve outlet pressure is too high, the corresponding evaporation pressure and temperature are too high.
The flow rate and pressure entering the evaporator are increased. Because the liquid evaporates excessively, the excessive moisture (or even liquid) is sucked by the compressor, causing the wet stroke (liquid blow) of the compressor, causing the compressor to fail to work normally, resulting in a series of work. Bad conditions, even damage the compressor.
The opening degree of the expansion valve should be adjusted according to the library temperature at that time, that is, adjusted under the pressure corresponding to the reservoir temperature.
For example: the storage temperature is -10 degrees, the evaporation temperature of the cold storage should be about 5 degrees lower than the storage temperature, that is, -15 degrees and the corresponding evaporation pressure is about 0.96 kilograms (R22).
Due to the pressure loss factor, the regulated pressure is substantially reflected in the suction pressure of the compressor.
The adjustment of the expansion valve must be carried out carefully and patiently.
The adjustment pressure must be exchanged by the evaporator and the reservoir temperature to evaporate (evaporate) and then flow through the pipeline into the compressor suction chamber to reflect the pressure gauge. It takes time.
Each time the expansion valve is mobilized, it usually takes 10~15 minutes to stabilize the adjustment pressure of the expansion valve on the suction pressure gauge, and the adjustment cannot be rushed.
The suction pressure of the compressor is the main parameter for adjusting the pressure of the expansion valve.
The technical performance of the expansion valve directly affects whether it can properly regulate the operation of the logo. It is usually prone to failures such as clogging of the filter and leakage of the temperature-sensitive agent.
The adjustment reaction is not sensitive, the adjustment is out of control or cannot be adjusted. When the frost is formed at the inlet of the expansion valve (or the valve cover is also frosted), the temperature of the inlet pipe is lower than normal temperature and even condensation.
For example, the suction pressure of the compressor is lower than the corresponding pressure at the storage temperature, the operating temperature of the machine and the exhaust temperature are high, and the cooling temperature drops slowly or not.
It may be that the filter of the expansion valve is blocked, and there is dirty or ice blockage. Phenomenon (or leakage refrigerant).
1. Close the main valve for liquid supply and turn on the compressor. When the suction pressure is stable below 0, close the exhaust valve of the compressor and stop the compressor at the end of the shutdown (finished fluorine).
2. Disassemble the inlet of the expansion valve, take out the filter and clean it, replace it, and replace the infusion drying filter or filter. Check the performance of the infusion solenoid valve and restore it (check the cleaning).
3. Open the exhaust bypass port of the compressor (others are still in the state of receiving fluorine), start the operation, and let the air from the liquid supply main valve to the compressor body be completely withdrawn from the exhaust bypass port, and the suction pressure is stable.
When the vacuum is below 0 (the pumping is completed), the exhaust bypass port is closed, the exhaust valve of the compressor and the liquid supply master valve are opened, and the system resumes operation.
If the expansion valve itself works normally, it is only because of the blockage caused by excessive moisture or dirt in the system, causing serious ice blockage or dirty blockage, which makes the system work abnormally.
The temperature of the expansion valve advances the liquid pipe to be lower than normal temperature, even condensation, the valve after the valve has no temperature reaction, the suction pressure of the compressor is below 0, the machine operating temperature and exhaust temperature is high, and even the knocking sound, the cooling temperature does not drop, and the operating conditions are bad.
Excessive system moisture:
1, the usual maintenance vacuum is not complete;
2. The leakage causes the low pressure to continue to operate under negative pressure and inhale the moisture;
3. The system has been put on for too long after being disassembled;
4. The resurgence of the parts is sticky;
5. The excess of water in the refrigerant is excessive;
6. The condensation tube of the water-cooled condenser is broken;
The reason for the excessive accumulation of the system is mainly due to the precipitation of the tubular oxide and the water-cooled condenser iron oxide and other pollutants of the system with the circulation of the working fluid.
Inspection of compression efficiency of the compressor: close the suction and exhaust valve of the compressor, open the exhaust bypass port (multiple ports), start the compressor operation, the low pressure of the compressor will quickly form a vacuum and the exhaust port of the exhaust port.
Gradually become smaller, and soon there will be no more gas discharge, the running noise will gradually become smaller, and the exhaust bypass port will be discharged without oil.
When the exhaust bypass port (multiple ports) is closed, the low pressure vacuum of the compressor will not be fast.
Pick-up, high and low pressure will take 10-15 minutes to balance, indicating that the compression efficiency of the compressor is good, and the sealing of the valve meets the requirements.
If the exhaust port of the compressor always has gas discharge, or it will bring out (spray) the lubricating oil, it is enough to show that the compression performance of the compressor is poor, the airtightness of the valve is not strict, and the operating position of the cylinder and The wear gap of the oil ring is too large.
Repairs are required. This is the most basic, simplest and most practical method for testing the compression efficiency and airtightness test of a compressor.
In addition, the system should be drained and vented frequently or periodically to improve the heat exchange performance and cooling performance of the heat exchanger.
Since the frozen oil has a large viscosity, it is usually adsorbed on the inner surface of the pipe or the container to form an oil film layer.
Especially on the low pressure side (expansion valve outlet to compressor inlet), the viscosity of the oil is larger due to the lower temperature, and the oil film layer is, of course, larger, thus increasing the heat exchanger (evaporator and condenser).
Thermal resistance affects heat transfer performance and reduces the cooling effect. The more oil in the system, the greater the drawback, so it is very detrimental to refrigeration.
The presence of air or other non-condensable gases in the system will cause the condensing pressure and temperature to rise, the power consumption to increase, the operating temperature of the compressor to be high, the load to be heavy, and the cooling efficiency to be lowered.
The exhaust pipe evaporator can use the lowest discharge port to drain the oil; the lowest outlet of the chiller combined evaporator generally has an oil drain (sewage) port.
The oil discharge and air discharge operations should be carried out under the static shutdown of the system. The air release should also be carried out when the temperature is low, so the effect will be better.
For systems that do not have a dedicated air release unit, the air outlet is generally selected at the highest point on the high-pressure side.
The evaporation tube of the cold storage and the fin tube of the cooling fan must be defrosted in time (time) to ensure its good heat transfer effect.
10 kinds of cold storage room common fault problems and solutions
1. Initial operation of cold storage equipment:
The initial operation of cold storage equipment should always observe the oil level and oil return of the compressor and the cleanliness of the oil.
It is found that the oil is dirty or the oil surface should be resolved in time to avoid poor lubrication.
2. Always observe the operating status of the heart compressor of the cold storage equipment:
Check the exhaust temperature.
When operating in the season, pay special attention to the operating status of the system, and adjust the system liquid supply and condensation temperature in time.
3, Do not start for a long time or start the machine for a long time without stopping or the temperature of the library is not stopped:
Check whether there is dirt on the condenser, the heat dissipation will cause the condensing pressure of the refrigerator to be too high.
In order to protect the compressor, in the pressure controller Under the action of the machine stops running, wait until the heat is good, press the black reset button on the voltage controller, the machine will automatically resume operation.
4, usually by observing the changes of the instrument:
listening to the sound of the machine running, touching the temperature changes of the machine and other methods to observe the operating state of the compressor found that the compressor has a string of gas and other phenomena should be repaired or replaced in time.
5, cold storage due to poor insulation or sealing performance, resulting in a large loss of cooling capacity:
The poor thermal insulation performance of the cold storage is due to insufficient thickness of insulation layer of pipelines, warehouse insulation walls, etc., insulation and insulation effects are not good.
It is mainly designed insulation The thickness of the layer is not properly selected or the quality of the insulation material is poor during construction.
Or the insulation and moisture-proof performance of the insulation material may be destroyed, causing the insulation layer to be damp, deformed or even smashed, and its thermal insulation capacity is reduced, and the loss of the cold storage capacity of the storage is increased, and the temperature drop of the storage is obviously slowed down.
6. The surface of the cold storage evaporator is too thick or excessively dusty:
the heat transfer effect is reduced to prevent the frost layer on the surface of the evaporator from being too thick, and it needs to be defrosted regularly.
In addition to excessive frosting, the heat transfer effect of the evaporator is not good.
The surface of the evaporator is too thick for long-term not cleaning, and its heat transfer efficiency is also significantly reduced.
7. There is more air or refrigeration oil in the evaporator:
The heat transfer effect is reduced.
Once the evaporator has more refrigerant oil on the inner surface of the heat transfer tube, the heat transfer coefficient will be reduced. Similarly, if the heat transfer tube is there is more air,
the heat exchange area of the evaporator is reduced, the heat transfer efficiency is also significantly reduced, and the warehouse temperature drop rate is slowed down.
8. Improper adjustment or blockage of the cold storage throttle valve:
If the refrigerant flow rate is too large or the throttle valve is improperly adjusted or blocked, it will directly affect the refrigerant flow entering the evaporator.
When the opening degree of the throttle valve is too large, the refrigerant flow rate is too large, and the evaporation pressure and the evaporation temperature also increase.
Meanwhile, when the throttle valve opening degree is too small or blocked, the refrigerant flow rate also decreases, and the system flow rate is also reduced.
The amount of cooling is also reduced. Generally, by observing the evaporation pressure, evaporation temperature and frosting of the suction pipe to judge whether the throttle valve refrigerant flow is suitable, the throttle valve blockage is an important factor affecting the refrigerant flow rate, and the main cause of the throttle valve blockage is ice.
Blocking and dirty plugging. The ice blockage is due to the poor drying effect of the dryer. The refrigerant contains moisture.
When flowing through the throttle valve, the temperature drops below 0 °C, and the moisture in the refrigerant forms ice and blocks the throttle hole.
The dirty plug is Due to the accumulation of more dirt on the filter inlet of the throttle valve, the refrigerant flows poorly and forms a blockage.
9. Insufficient refrigerant amount in the cold storage system:
Insufficient cooling capacity There are two main reasons for insufficient refrigerant circulation in the cold storage.
First, the refrigerant charge is insufficient. In this case, only enough refrigerant can be added. One reason is that the system refrigerant leaks more.
In the case of such a situation, the leak point should be searched first. The pipelines and valves should be inspected to find out the leaked parts and then filled with a sufficient amount of refrigerant.
10, the compressor efficiency is low:
The cooling capacity cannot meet the warehouse load requirements.
Due to the long-term operation of the compressor, the cylinder liner and piston ring and other components are seriously worn.
The matching clearance will increase, the sealing performance will decrease accordingly, and the compressor’s gas transmission coefficient will also follow.
The reduction will reduce the cooling capacity. The refrigeration capacity of the compressor can be roughly judged by observing the suction and exhaust pressure of the compressor.
If the refrigeration capacity of the compressor drops, the common method is to replace the cylinder liner and piston ring of the compressor.
If it still fails to work after replacement, other factors should be considered, even disassemble and repair, and eliminate the fault factor.
Determining the Price Factor of A Cold Storage Room
- For refrigeration units: (size of refrigeration units, the brand of refrigeration units, the origin of refrigeration units, type of refrigeration units).
- In terms of cold storage panels: (types of cold storage panels, the thickness of cold storage panels, types of cold storage panels, size of cold storage panels).
- Refrigerator services: (whether to sign a contract for cold storage installation, whether to maintain, whether to maintain, whether to regularly repair).
- In the aspect of cold storage temperature: (the temperature of cold storage, the running time of cold storage, etc.)
The quotation of a complete cold storage project includes many aspects, which we will illustrate with a case.
Firstly, technicians are required to calculate and evaluate the design plan and drawings after the site survey. Costs usually include the following aspects:
1. Storage cost: such as polyurethane board, beam/column reinforcement, top and bottom, etc. If some surfaces need foundation concrete and other structures, depending on the specific situation, one party is responsible.
2. Unit Cost: Cooling Compressor Unit – a very important part of the cold storage.
3. Cost of accessories: such as cold storage doors, air coolers, cooling towers, pumps, pipes, liquid storage tanks, separators, lines, switches… Wait.
4. Miscellaneous expenses: such as transportation, defrosting drainage system, labor and so on. Finally, the budget cost of cold storage is obtained.
The cost of cold storage is affected by many factors, so the price of cold storage is different.
As for how much is it to build cold storage, it is impossible to give a reasonable answer.
After all, the size of the cold storage, the temperature of the cold storage, what to put in the cold storage, and the refrigeration capacity needed for the cold storage should be systematically planned.
How to maintain and repair your cold storage room
Dryer filter will separate the water from the refrigeration system to prevent ice blockage.
Note: Always replace the dry filter when replacing major components such as compressors and condensers, as well as refrigerant and oil.
Separating the refrigerant in the gas-liquid mixed state returned by the evaporator to prevent the compressor from colliding.
Observe the flow rate of the refrigerant from the sight glass. When the refrigerant is suitable, only the liquid flows, and there is no white bubble.
When there is no moisture in the system, the center of the sight glass is green, otherwise, it is yellow or other abnormal colors.
Construction diagram of the combined cold storage:
Cold storage door use:
1. To prevent damage to the cold storage door, please lightly open the door.
2. In order to prevent the leakage of cold air, please quickly close the cold storage door to avoid the cold storage fan opening due to the cold storage door for a long time.
The hot air intrusion causes serious frosting of the fins, resulting in poor refrigeration in the cold storage.
The cold storage goods are correctly displayed:
When placing goods in the warehouse, be careful not to block the suction/exhaust ports of the cold storage fan. Keep the suction/exhaustion air unblocked and distribute the cooling evenly.
The goods placed on the left and right, above and below the interval of 5cm, in order to facilitate the flow of cold air.
Ensure the smooth flow of the air outlet and the suction inlet:
It is often seen that the suction port is blocked by the product, which reduces the intake of the cold air, resulting in a decrease in cooling capacity and damage to the product.
Cold storage thermostat:
The thermostat can adjust parameters such as cold storage temperature, defrost time, and the number of defrosts.
Cold storage can not stack debris:
The top of the cold storage is designed to be non-load-bearing, and there are refrigerant piping and electrical piping, which does not allow users to stack items to avoid accidental damage. The cold storage light switch is turned off.
Product storage Note the equipment in the library:
The amount of restocking per cold storage generally does not exceed 20% of the total capacity of the cold storage. Be careful not to damage the downpipe, refrigerant pipe, etc. when purchasing.
Regular cleaning in the cold storage:
Clean the cold storage regularly to avoid odor. When cleaning, please turn off the power switch first. Be careful not to let water immerse in the library light switch, evaporator junction box, etc.
Cold storage defrost:
Cold storage defrost is an electric heating automatic defrost method. When the air humidity is high in summer, it is easy to cause the evaporator to block or freeze.
Please do not use hard objects to chip the ice, which will easily cause the evaporator coil to leak. The correct treatment is to use warm water combined with forced defrosting to remove ice, and then increase the number of defrosting and defrosting time.
Defrosting of the evaporator will reduce the cooling capacity. In order to prevent this phenomenon, it is necessary to reduce the number of inbound and outbound storage.
In order to access the library, the library door needs to be closed, and when the frosting is excessive, defrosting must be performed.
Please follow the settings of the defrost timer or the cold storage microcomputer controller installed in the freezer unit.
Too much frost will cause the machine head to return to liquid. In severe cases, a liquid hammer will occur, resulting in damage to the compressor head.
Management temperature of the equipment room:
Cold storage light switch people go lights to extinguish the room temperature – commonly below 35 ° C, summer short-term can be below 40 ° C. The machine room temperature is too high will occur the following problems:
1. The intake air temperature and the exhaust gas temperature increase, resulting in a decrease in the refrigeration capacity;
2. The decrease in refrigeration capacity increases the operating rate, which increases power consumption and increases operating costs.
The standard for the setting conditions of the freezer:
1. Due to the increase of load, the exhaust gas temperature rises to reduce the life of the freezer; in order to prevent the refrigerator from malfunctioning due to excessive temperature,
it will be forced to stop; the liquid refrigerant is heated to generate flash steam, thereby reducing the circulation of the refrigerant and making the cooling poor.
2. Ventilation and ventilation of the compressor room
In order to prevent the exhaust gas from being trapped in the refrigeration unit, a ventilation device is required in the equipment room.
The ventilation fan directly faces the door or window; the area of the ventilation opening is the effective size of the internal dimension of the door (or window); in principle, the mechanical ventilation device as the exhaust device must ensure the required exhaust capacity.
The operating temperature of the poorly ventilated compressor is increased, and the service life of the freezer is increased and the energy consumption is increased.
The freezing oil level is between the lower limit of the oil mirror and the oil is not turbid. There is a float valve in the oil separator, which works intermittently to make the return pipe hot when it is cold.
When the oil returns to the oil, the pipe is hot. When the oil return is stopped, the pipe is cold. If it is cold or hot, it indicates that the float valve has failed. Regular inspection and cleaning
Why your cold room is a bad cooling performance?
There are many reasons why the temperature of the cold storage room cannot fall down.
1. The surface of the evaporator is too thick or excessively dusty, and the heat transfer effect is reduced
When the frost layer on the surface of the evaporator is too thick or dusty, the heat transfer effect of the evaporator will inevitably decrease.
Since the surface temperature of the cold storage evaporator is mostly lower than 0 ° C, and the humidity of the warehouse is relatively high, the moisture in the air is easily frosted on the surface of the evaporator, and even freezes, which affects the heat transfer effect of the evaporator.
To prevent the surface of the evaporator from being too thick, it needs to be defrosted periodically.
2.cold storage room due to poor insulation or sealing performance, resulting in a large loss of cooling capacity
The poor thermal insulation performance is due to the insufficient thickness of the insulation layer of the pipeline, the warehouse insulation wall, etc., and the poor insulation and insulation effect.
It is mainly caused by the improper selection of the thickness of the insulation layer during design or poor quality of the insulation material during construction.
In addition, during the construction and use process, the thermal insulation moisture resistance of the thermal insulation material may be destroyed, resulting in the insulation layer being damp, deformed, or even eroded.
The thermal insulation capacity is reduced, the loss of the cold storage capacity is increased, and the storage temperature is significantly slowed down.
Another important reason for the large loss of cold is that the warehouse has poor sealing performance, and more hot air invades the warehouse from the leak.
Generally, if condensation occurs in the seal of the warehouse door or the seal of the cold storage wall, it means that the seal is not tight.
In addition, frequent switching of the warehouse door or more people into the warehouse together will also increase the cooling capacity of the warehouse.
Try to avoid opening the door to prevent large amounts of hot air from entering the warehouse.
Of course, when the warehouse is infrequent inventory or the quantity of goods is too large, the heat load increases sharply, and it takes a long time to cool down to the specified temperature.
3. There is more air or frozen oil in the evaporator, and the heat transfer effect is reduced
Once the inner surface of the evaporator heat transfer tube is attached with more refrigeration oil, the heat transfer coefficient will be reduced.
Similarly, if there is more air in the heat transfer tube, the heat exchange area of the evaporator is reduced, and the heat transfer is reduced.
The efficiency will also drop significantly, and the rate of decline in the warehouse temperature will slow down.
Therefore, in daily operation and maintenance, attention should be paid to timely clearing the oil on the inner surface of the evaporator heat transfer tube and discharging the air in the evaporator to improve the heat transfer efficiency of the evaporator.
4. The throttle valve is improperly adjusted or blocked, and the refrigerant flow rate is too large or too small.
Improper adjustment or blockage of the throttle valve will directly affect the flow of refrigerant into the evaporator.
When the opening degree of the throttle valve is too large, the refrigerant flow rate is too large, the evaporation pressure and the evaporation temperature also increase, and the warehouse temperature drop rate will be slowed down;
meanwhile, when the throttle valve opening degree is too small or blocked, the refrigerant The flow rate is also reduced, the cooling capacity of the system is also reduced, and the rate of decline in the warehouse temperature will also slow down.
Generally, it can be judged whether the flow rate of the throttle valve refrigerant is appropriate by observing the evaporation pressure, the evaporation temperature, and the frosting condition of the suction pipe.
Blockage of the throttle valve is an important factor affecting the flow rate of the refrigerant. The main cause of the blockage of the throttle valve is ice blockage and dirty blockage. The ice blockage is due to the poor drying effect of the dryer.
The refrigerant contains moisture. When flowing through the throttle valve, the temperature drops below 0 °C, and the moisture in the refrigerant forms ice and blocks the throttle hole; the dirty plug is Due to the accumulation of more dirt on the filter inlet of the throttle valve, the refrigerant flows poorly and forms a blockage.
5. the chiller compressor efficiency is low, the cooling capacity can not meet the warehouse load requirements
Due to the long-term operation of the compressor, the components such as the cylinder liner and the piston ring are seriously worn, the clearance is increased, the sealing performance is reduced, the gas transmission coefficient of the compressor is also reduced, and the cooling capacity is reduced.
When the cooling capacity is less than the heat load of the warehouse, it will cause the warehouse temperature to drop slowly.
The refrigeration capacity of the compressor can be roughly judged by observing the suction and exhaust pressure of the compressor.
If the refrigeration capacity of the compressor drops, the common method is to replace the cylinder liner and piston ring of the compressor.
If it still cannot be effective after replacement, other factors should be considered, and even disassemble and repair, to eliminate the fault factor.
6. Insufficient refrigerant in the system, insufficient cooling capacity
There are two main reasons for the lack of refrigerant circulation.
First, the refrigerant charge is insufficient. In this case, it is sufficient to fill in a sufficient amount of refrigerant.
Another reason is that the system refrigerant leaks more. In the case of such a situation, the leak point should be found first, and the connection points of each pipeline and valve should be checked. After the leak is repaired, a sufficient amount of refrigerant
How to keep the cold storage room good condition and cooling performance, the maintenance is the key point.
- Temperature control protection, after the cold storage room is newly installed or long-term decommissioning, use it again. The speed of cooling should be reasonable: It should be controlled at 8-100C every day, and should be kept at 00C for a while.
- cold storage board protection, pay attention to the use of hard objects on the collision and scratching of the library. Because it can cause the depression and rust of the cold storage board, it will seriously reduce the local insulation performance of the storage body.
- cold storage board protection, pay attention to the use of hard objects on the collision and scratching of the library. Because it can cause the depression and rust of the cold storage board, it will seriously reduce the local insulation performance of the storage body.
- Ground protection. Generally, use the thermal insulation board in the small assembly cold storage. When using cold storage, prevent the ground from storing a lot of ice and water. If there is ice, do not use hard objects to knock and damage the ground.
What are the causes of cold room refrigeration chiller unit compressor frosting?
The following major points are considered in the occurrence of compressor frosting:
- Too much refrigerant
Too much refrigerant causes the evaporator to evaporate incompletely. The refrigerant that has not completely evaporated migrates to the suction pipe, causing the suction pipe to frost, and then migrates to the compressor suction cylinder, absorbing a large amount of heat from the compressor, causing compression frost.
- The expansion valve opening is too large (expansion valve failure)
If the opening of the expansion valve is too large, it will inevitably lead to an increase in the amount of refrigerant entering the evaporator, which will eventually cause the compressor to frost.
- Air blower problem
Fan air volume failure (small air volume) → Evaporator evaporation is not good → Refrigerant evaporation is not complete → Evaporator frosting → Suction tube frosting → Compressor frosting
- Dirty evaporator
The evaporator is dirty → The evaporation of the evaporator is not good → The refrigerant evaporation is not complete → The evaporator is frosted → The suction tube is frosted → The compressor is frosted
- The evaporator design is small
If the evaporator design is small, it will cause the refrigerant to evaporate in the evaporator incompletely, which will lead to serious frosting of the evaporator, and the slow frosting will migrate to the compressor.
If the defrosting of the evaporator fails, it will also cause frosting of the compressor. The main situation can be summarized as follows:
1, defrost failure
It is the defrosting of the evaporator that fails, does not work at all, resulting in no defrosting at all, it is likely that the defrosting temperature control fails.
If the evaporator can not be defrosted, it will cause the whole evaporator to frost. It is obvious that the overall frosting of the evaporator will inevitably lead to incomplete evaporation of the refrigerant in the evaporator. According to the above analysis, the compressor will gradually become frosted.
2, the defrosting is not complete
There are many ways to defrost the evaporator now:
Four-way valve defrosting,
Hot air defrosting,
Water cream, etc.;
However, all these defrosting methods may result in incomplete defrosting.
For example, if the defrosting time is not enough, the evaporator defrosting is not complete, and under the slow accumulation, the evaporator will inevitably cause serious frosting, which will cause the compressor to frost.
Does the refrigerant lacking cause frosting of the compressor?
Yes. Please see below explanation:
The first reaction of everyone is that there is less refrigerant, and the system has a large suction superheat, that is, the suction temperature of the compressor will be very high. How can it cause the compressor to frost?
1. Due to the extremely low flow rate of the refrigerant, the refrigerant will start to expand from the rear end of the throttle valve after the rear end of the throttle valve. Most of us see that the rear end of the expansion valve is often due to lack of fluorine or expansion valve. The traffic is not enough.
Too little refrigerant expansion will not use all the evaporator area, only low temperature will be formed in the evaporator part, and some areas will be rapidly expanded due to the small amount of refrigerant, causing the local temperature to be too low, and the evaporator frosting will occur. After local frosting, The heat exchange amount in this region is low due to the formation of a heat-insulating layer on the surface of the evaporator.
The expansion of the refrigerant is transferred to other areas, and the entire evaporator is frosted or frozen, and the entire evaporator forms a heat insulation layer. Then the expansion spreads to the compressor return pipe, causing the compressor to return to the air and frost, which in turn causes the compressor to frost.
2. Because the amount of refrigerant is too small, the evaporation pressure of the evaporator is low, resulting in low evaporation temperature, which will gradually lead to condensation of the evaporator to form a heat insulation layer, and transfer the expansion point to the compressor return air to cause the compressor to return to the air.
Both of the above points will show the evaporator frosting before the compressor returns to the air.
Why TopChiller can be your reliable cold storage room supplier?
TopChiller can do Custom Designed Cold Storage
We start with an onsite inspection, where we consider your requirements for the cold storage room, and design a perfect solution that fits the space and your storage and usage needs.
We then manufacture our durable, reliable insulated thermal panels, custom manufacture cold room doors, and supply and install your refrigeration equipment if required.
Our team of qualified electrical and lighting technicians will take care of wiring and lighting, and our flooring team will install tough and durable concrete.
For a cost-effective and budget-friendly cold room solution, TopChiller offer do-it-yourself thermal and insulation panel and door kits that are easily put together.
All components are pre-cut for rapid and easy assembly on-site, using basic tools such as screwdrivers, drills and a blind riveter, and can easily be erected by either an experienced tradie or amateur DIYer.
If you can put together flat-pack furniture, you can put together our cool room kits!
Calculation of Cooled RoomRefrigeration Capacity and Calculation of Evaporator, Condenser based on Throughput
Calculation of heat exchange area of air-cooled condenser: cooling capacity + compressor motor power 200 (200~250) m2
The ratio of the water-cooled condenser to the air-cooled condenser is generally 1:15, such as 300 m2 for an air-cooled condenser and 300 ÷ 15 = 20 m2 for a water-cooled condenser. The difference in cooling water quality can be appropriately reduced to about 1:10.
For example, a warehouse of 60 cubic meters, storage temperature of -18 ° C, the ratio of the air-cooled evaporator (cooling fan) is generally similar to the cooling power of the compressor.
For example, the warehouse of 60 cubic meters, the storage temperature is -18 °C, and the evaporator adopts the suspended aluminum row, which can be configured according to the bottom area of the warehouse (that is, the bottom area of the warehouse is X2).
For example, a warehouse of 60 cubic meters, storage temperature of -18 ° C, the evaporator must be divided into at least 2 (two groups), each group (road) of the thermal expansion valve spool is smaller than the number of compressors.
The configuration of the expansion valve is determined based on the cooling capacity of the compressor and does not need to be amplified by 20%.
The evaporation area of the aluminum discharge is fixed, and only the compressor is increased. Although the unit cooling capacity is increased and the heat exchange rate is increased, the overall heat exchange amount is based on the evaporation area, and it is impossible to become a quick-freezer.
The volume utilization factor of the cold storage:
Food unit weight of combined cold storage:
Frozen meat = 0.40 tons / cubic
Frozen fish = 0.47 tons / cubic
Fresh fruits and vegetables = 0.23 tons / cubic
Mechanism ice = 0.75 tons / cubic
Frozen sheep cavity = 0.25 tons / cubic
Bone-cut meat or by-products = 0.60 tons / cubic
Boxed frozen poultry = 0.55 tons / cubic
Combined cold room storage capacity calculation method:
In the warehousing industry, the formula for calculating the maximum warehousing volume is: effective internal product (m3) = total internal volume (m3) × 0.9
Maximum storage capacity (tons) = total internal volume (m3) / 2.5m3
The actual maximum storage capacity of the combined cold storage
Effective internal product (m3) = total internal volume (m3) × 0.9
Maximum storage capacity (ton) = total internal volume (m3) × (0.4-0.6) / 2.5m3
In the case where there is no special designation, the actual daily storage volume is calculated according to the maximum storage capacity (ton) of 15%-30% (generally less than 100 cubics is calculated at 30%, and greater than 1000 cubic meters is calculated at 15%).
Cold storage cooling capacity calculation formula:
Generally, the calculation formula of the high-temperature activity cold storage cooling capacity is: cold storage volume × 90 × 1.16 + positive deviation, the positive deviation is determined according to the condensation temperature of the frozen or refrigerated goods, the storage amount, the frequency of the goods entering and leaving the warehouse, and the range is between 100-400W. .
The formula for calculating the cooling capacity of the medium-temperature activity cold storage is: cold storage volume × 95 × 1.16 + positive deviation, positive deviation range between 200-600W.
The calculation formula of the refrigeration capacity of the low-temperature activity cold storage compressor unit is: cold storage volume × 110 × 1.2 + positive deviation, positive deviation range is between 300-800W.
Some commonly used refrigeration unit
1 MW (MW) = 1000 kW (kW)
1 kW = 1000 W
1 kW = 861 kcal / h (large card) = 0.39 P (cold)
1 W = 1 J/s (joules per second)
0.1 MPa=1kg/cm2=10 mH2O=100 kPa
1 USRT (US cold tons) = 3024 kcal / h = 3517 W (cold)
1 BTU (British thermal unit) = 0.252kcal / h = 1055 J
1 BTU/h (British thermal unit / hour) = 0.252 kcal / h
1 BTU/h (British heat unit/hour) = 0.2931 W (cooling capacity)
1 MTU/h (thousands of thermal units per hour) = 0.2931 kW (cold)
1 HP (electricity) = 0.75 kW (electric)
1 kW (electricity) = 1.34 HP (electric)
1 RT ((cold) = 3.517 kW (cold)
1 kW (cold) = 0.284 RT = 860 kcal / h = 3.412 MBH (103 BTU / h)
1 P (cooling capacity) = 2200 kcal / h = 2.56 kW
1 kcal/h=1.163 W
1 W=0.86 kcal/h
°F (Fahrenheit) = 9/5 ° C + 32
°C (degrees Celsius) = (°F-32) 5/9
1 CFM (cubic feet per minute) = 1.699 m3/h = 0.4719 L/s
1 m3/h = 0.5886 CFM (cubic feet per minute)
1 L/s = 2.119 CFM (cubic feet per minute)
1 GPM (gallons per minute) = 0.006308 L/s
1 L/s = 15.85 GPM (gallons per minute)
1 kg/cm2=10 mH2O=1 bar=0.1 MPa
1 Pa=0.1 mmH2O=0.0001 mH2O
1 mH2O=104 Pa=10 kPa
1kcal (large card):
At a standard atmospheric pressure, the temperature of 1 kg of water rises or falls by 1 ° C, and the amount of heat absorbed or released is 1 calorie.
In summer cooling, the ratio of the cooling capacity (W or Btu/h) to input power (W) is defined as the energy efficiency ratio of the heat pump.
When heating in winter, the ratio of heat (W) to input power (W) is defined as the coefficient of performance of the heat pump.
The integrated partial load performance factor is a single value indicating the partial load efficiency index of the air conditioning chiller.
Cold storage cooling capacity estimation:
Regardless of the type of compressor group selected, it is determined according to the evaporation temperature of the cold storage and the effective working volume of the cold storage.
In addition, the parameters such as the condensing temperature of the frozen/refrigerated items, the storage quantity, and the frequency of the goods entering and leaving the warehouse are also referred to.
The formula for calculating the cooling capacity of the high-temperature cold storage is: cold storage volume × 90 × 1.16 + positive deviation, and the positive deviation is determined according to the condensation temperature of the frozen or refrigerated goods, the storage amount, and the frequency of the goods entering and leaving the warehouse, and the range is between 100-400W.
The formula for calculating the cooling capacity of the medium-temperature activity cold storage is: cold storage volume × 95 × 1.16 + positive deviation, positive deviation range between 200-600W.
The formula for calculating the cooling capacity of cold storage is: cold storage volume × 110 × 1.2 + positive deviation, positive deviation range is between 300-800W.
These issues should be noted in the management of cold storage
The use of cold storage should be based on design requirements, to fully exert the freezing and refrigeration capacity, to ensure safe production and product quality, and to maintain the cold storage building structure.
The management of the warehouse should have a special team, and the responsibility should be implemented for the people.
Every warehouse door and every piece of equipment and tools must be staffed. Using practical experience, we must pay attention to the following aspects in the management of cold storage buildings.
1. Strictly prevent the insulation layer of the envelope structure from being damaged by moisture
The cold storage is built with heat-insulating materials. It has the characteristics of being afraid of water, afraid of moisture, fear of heat, and fear of running cold. It is necessary to put five ice, frost, water, doors and lights.
There should be no ice, frost, or water in the walls, floors, doors, and ceilings of Chuantang and Treasury. The cooling fan in the library should promptly sweep the frost and flush the frost to improve the cooling efficiency.
When flushing the cream, it must be operated according to the regulations. At least, it is necessary to clear the library once and freeze the frost. There shall be no water in the water tray of the air cooler and in the storage tank.
In use, there should be no occurrence of damage to the waterproof vapor barrier layer of the envelope structure, and the leakage of water from the roof should be prevented from invading the insulation layer.
Do not wash the floor, roof and wall with water. It is necessary to remove ice, frost and water from the store in time. It is not allowed to carry out the multi-aqueous operation of the cold room, and it is never allowed to carry out multi-water production.
2. to prevent freezing and thawing cycles from damage to the cold storage building structure
Cold rooms should be used according to the intended use.
If it is not a dedicated dual-use refrigerated room, the high and low temperature refrigerating rooms should not be confused. Goods that have not been frozen are not allowed to enter the frozen storage room to ensure the quality of the goods and prevent damage to the cold storage.
In the absence of commodity storage or cold processing, it is also necessary to maintain a suitable warehouse temperature. The freezing room and the low temperature refrigerating room should be below -5 °C, and should not rise above 0 °C, otherwise it will cause freezing and thawing cycles.
The high temperature refrigerating compartment and cooling (pre-cooling) should be below the dew point temperature to avoid dripping water in the reservoir. To control the number of incoming goods and to master a reasonable temperature, do not cause the library to drip.
Also, pay attention to whether the heat-resistant bridge is damaged or not, and if it is found, it should be repaired in time.
3.to avoid ground frost heave and damage the floor (ground) surface
The overhead layer under the overhead anti-freezing ground is used as a high-temperature refrigerating room.
The ground under the overhead layer is not used as a thermal insulation layer, and its temperature should be controlled above 0 °C.
To heat the anti-freezing ground, regularly check the ventilation pipe under the ground for frost clogging and water accumulation (to check whether the oil pipe is blocked or damaged by oil pipe heating), whether the return air (oil) temperature meets the requirements, and avoid operation Improper management causes ground frost heave.
Natural ventilation to heat the anti-freezing ground, in addition to checking the presence or absence of frost in the air duct, the vent pipe port is strictly prohibited to stack items, affecting natural ventilation.
The design load of the floor and floor of the cold storage is specified in the design specification. The weight of the goods in the warehouse, the means of transport and its load, and the load capacity of the hanging rails shall not exceed the specified service load.
When unhooking and unplugging, it is not allowed to fall on the floor (ground) surface. It is even more difficult to spread the moisture-rich goods directly on the floor or on the ground to freeze. Otherwise, it will damage the building and the ground, and the heavy will cause an accident.
4. must make reasonable use of the cold storage room space
In order to make the goods piled up safely and tidy, to ensure the quality of the goods, easy to inspect and inventory, easy to enter and leave the warehouse, safe transportation operation.
The distance between the goods in the warehouse and the wall, roof, cooling equipment and walkways must be Meet the requirements and improve the stacking capacity of the warehouse by reasonably arranging the cargo stacking method under the conditions of the load on the floor (ground) surface to ensure smooth return of the wind.
Foods with odors should be stored in a single room. It is not advisable to blindly pursue the utilization of the warehouse volume regardless of the use requirements and conditions of use of the warehouse.
5. Strengthen the management of the use of refrigerated doors
The refrigerated door is the passage throat for entering and leaving the cargo. During the transportation of the goods into and out of the warehouse, collisions should be avoided to damage the refrigerated door.
Refrigeration doors are also frequently opened and closed. Some have air curtains, but the heat and moisture exchange at the door openings is still very strong. The rational use of refrigerated doors involves both the cost of refrigeration and the quality of cold processing and storage of the goods.
Therefore, it is necessary to strictly manage the refrigerated door, so that it can be closed in time, flexible in opening and closing, tightly closed, and prevented from running cold. If it is damaged, it should be repaired in time.
The alarm inside the warehouse should be heard on the scene and in the waiting room for a long time, and the alarm device should remain intact.
6.goods in and out of the library and operation within the library
To prevent vehicles and goods from colliding with process equipment such as garage doors, columns, walls, and refrigeration system piping.
The electrical wiring in the warehouse should be maintained frequently to prevent leakage.
7. Strictly grasp the speed of cold storage and cooling and maintenance
When the cold storage is put into production and the temperature is raised, the temperature must be gradually and slowly carried out to adapt the building structure to the temperature changes, so as to avoid causing bad troubles.
Production cooling requirements: all floors and rooms of the cold storage should be cooled at the same time, so that the temperature stress and shrinkage rate of the main structure and each part of the structural layer are balanced to avoid cracks in the building.
The cooling rate before the cold storage is put into production is not more than 3 °C per day. When the warehouse temperature drops to 4 °C, it should be kept for 3-4 days, so that the free water in the cold storage building structure can be analyzed to reduce the hidden dangers of the cold storage, and then it is allowed to continue to cool down at a cooling rate of no more than 3 °C per day. To the required operating temperature of the design.
Maintenance temperature requirements: Before the overhaul or partial shutdown of the cold storage, the cold storage must be stopped. Before warming up, the frost in the storehouse must be cleaned to avoid water accumulation after thawing.
In the process of heating up, in case of melting frost water, it should be removed in time; if there is any danger of collapse, it should be treated first. The temperature rise should be carried out slowly.
The daily temperature rise should not exceed 2 °C, and the temperature of each warehouse should be kept fairly balanced.
The temperature of the reservoir should rise above 10 °C. The heating method must be safe to prevent accidents; local shutdown and maintenance should be carefully considered, measures should be taken well to prevent condensate or freeze-thaw cycles, and cracks in the building structure due to different temperature stresses.
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