Water Cooled Screw Chiller
- Cooling capacity 40Ton to 680Ton
- Temperature control 7℃ to 35℃
- Shell and tube evaporator and condenser
- Bizer or Hanbell semi-hermetic screw compressor
- Optional refrigerant R134a,R407c and R410a
- Safety protection devices of whole screw chiller
- All models and cooling capacity available
Your Premier Water Cooled Screw Chiller Manufacturer
As a leading water-cooled screw chiller manufacturer with almost 20 years of experience since 2003, TopChiller provides a complete range of water-cooled screw chiller from TPWS-WSH series.
The cooling capacity of screw water chiller is from 30Ton to 480Ton/105KW to 1688KW and the chiller temperature control range from +30℃ to -30℃.
Besides the standard water-cooled screw chiller control temperature from 7℃ to 30℃, TopChiller also has a water-cooled glycol screw chiller control temperature below zero from 0℃ to -30℃ for some special industrial applications.
With 20 years experience in design and manufacturing water-cooled screw chiller from TopChiller has the following features:
Using famous brand Semi-hermetic Screw Compressor- Bitzer from Germany and Handbell from Taiwan.
Each screw compressor comes with 4 steps of energy control 0-25%-50%-75%-100% to make sure the whole screw chiller operates when stable with high refrigeration performance.
Each water-cooled screw chiller with high-efficiency shell and tube type heat exchanger and aluminum foil with a copper tube air cooled condenser.
Integrated PLC control system with human-computer interface and big LED touch screen panel for easy operation.
Other refrigeration parts are world famous refrigeration spare parts like Danfoss thermal expansion valve, Alco dryer filter, Schneider contactor, and overload relay will make sure the whole screw chiller works under normal condition.
Compared with air cooled screw chiller, water cooled screw chiller should run together with external cooling tower and water pump. This is the biggest difference between air cooled screw chiller and water cooled screw chiller.
As a professional water cooled screw chiller manufacturer, TopChiller has exported many water cooled screw chillers to 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 are searching for a water-cooled screw chiller supplier, you are coming to the right place. TopChiller is a high reputation brand in the refrigeration market.
If you have any water-cooled screw chiller inquiry, please contact our engineering for a solution and free quotation.
TopChiller: Your Best Water Cooled Screw Chiller Supplier
Full protection devices including compressor overheating protection, low-temperature protection, high/low pressure, anti-freezing, phase-missing, anti-phase with overload, water flow switch and startup latency.
A various refrigerant such as R134a, R407c, R410a, and R404a are all available depending on screw chiller working condition, application requirements and ambient temperature.
Compared with air cooled screw chiller, this water cooled screw chiller is more efficient in cooling performance which is a requirement in condenser water pump and a cooling tower.
Besides the above features, TopChiller water-cooled screw chiller also has optional functions for special requirements including soft-starting, economizer for higher efficiency, complete stainless steel non-ferrous chilled water circuit for high water quality requirement, electronic expansion valve and remote control for monitoring the screw chiller working status.
Water cooled screw chillers are widely used for various industries applications such as HAVC, big building&hotel air conditioning, central chilled water supply, chemical processing, die casting,food&beverage processing, pet food, Pharmaceutical, plastic processing, automotive, energy&power project, packing, and printing.
TopChiller aims at providing water-cooled screw chiller with stable quality, operation efficiency, and energy savings. It is suitable for air conditioning applications, industry-type process cooling, and large-scale district heat source systems.
As a professional water-cooled screw chiller manufacturer, TopChiller provides all technical support to clients. Please contact TopChiller team to get the best water cooled screw chiller solution.
Water Cooled Screw Chiller: The Complete Buying Guide from TopChiller
- What Is Water Cooled Screw Chiller?
- How Does A Water Cooled Screw Chiller Work?
- Key Components of a Water Cooled Screw Chiller
- The Advantages of Water Cooled Screw Chiller Compared to Air Cooled Screw Chiller
- Industrial Applications of Water Cooled Screw Chiller
- Trouble Shooting of Water Cooled Screw Chiller
- Why TopChiller® Can Be a Reliable Supplier for Water Cooled Screw Chillers?
What Is Water Cooled Screw Chiller?
Water cooled screw chillers are devices used to dissipate heat from a location where the heat is not unwanted. Cost and efficiency are two crucial factors when considering the production of products.
As water-cooled screw chillers are equipped with cooling towers, they are more efficient than air-cooled chillers and are commonly used to cool products and machinery in a wide range of industrial applications including injection molding, tool and die cutting, beverage, lasers, machine tool, semiconductors and more.
Modern water-cooled screw chillers are also applied inside sophisticated diagnostic devices as they are efficient in preventing the temperatures of the machines from getting higher than expected.
How Does A Water Cooled Screw Chiller Work?
In the cooling process, it starts with a low-pressure liquid or gas mix entering the evaporator where the heat from the water changed to a low-pressure gas.
Then the gas went to the compressor to get compressed into a high-pressure gas, which then enters the condenser where ambient air or condenser water expels heat to transform it into a high-pressure liquid.
The heating and cooling of the refrigerant and its change from a gas to a liquid is so-called the refrigeration cycle.
Now let’s take a deep look at the key components of a water-cooled screw chiller.
Key Components of a Water Cooled Screw Chiller
1. Cooling Tower
Generally, the cooling tower is installed on the roof and is where the unwanted heat ends up.
Cooling towers are used to cool condenser water with the help of evaporation.
After the water is pumped to the cooling tower, it will flow down to the basin of the cooling tower and heat is released through evaporation during this process.
After the heat is released from water, the water will return to the chiller barrel through piping and absorbs more heat, then the water will go back to the cooling tower to get the heat released and the cycle continues.
TopChiller can provide you a full set of water cooling systems including: water cooled screw chiller, water pumps and water cooling tower.
But how to install a cooling tower? Please watch below the video of water cooling tower installation guide.
2. Semi-hermetic Screw Compressor
A screw-driven compressor is primarily used to compress the refrigerant with two interlocking rotating helical rotors.
Hanbell Screw Compressor
The screw compressor contains one or two screws which can compress the low-pressure refrigerant to a higher pressure refrigerant.
TopChiller water-cooled screw chillers are equipped with highly efficient, semi-hermetic compressor. This compressor enables 0%-100% step-less capacity control and achieves highest part-load efficiency, thus bringing about a huge saving on the electricity costs.
Hanbell semi-hermetic screw compressor is the regular compressor brand we are using for standard chiller models.
Hanebll screw compressor technical features:
Full product range- RC2 series compressor consists of 26 models with displacement ranging from 98/118 m3/hr up to 1539/1847 m3/hr (50/60Hz) compatible with different refrigerants and applications.
Multinational patents of high-efficiency screw rotors- The new 5:6 high-efficiency screw rotor profile is patented in Taiwan, UK, US, and China.
This new large-volume, high-efficiency rotor profile is designed especially for modern refrigerant characteristics. High-efficiency screw rotors are accomplished by using precision CNC machining centers, rotor milling machines, rotor grinding machines.
Strict ISO 9001 process controlling and the application of precise inspection equipment, such as ZEISS 3D coordinate measuring machines, ensure high-efficiency, high-quality, low noise and low-vibration HANBELL RC2 series screw compressors.
High-efficiency motor- Premium grade low-loss core steel with special motor cooling slot and refrigerant guide vane which pilot the cold suction refrigerant gas through the motor provides the highest operating efficiency possible no matter how strict operating conditions are.
Long life bearings and high reliability- The screw compressors utilize a combination of 10 axial and radial bearings and α axial balance piston to ensure longer bearing life and higher compressor reliability.
Double-walled rotor housing- Double casing structure with high strength inner ribs has been designed to minimize noise and ensure rigidity. The rotor housing is made of high-strength gray cast iron FC25 that is extremely stable.
therefore no expansion will occur even at the high-pressure condition. These casings are machined by computer-aided machining centers and inspected by precision measuring machines to enhance reliability.
Direct flange-on oil separator- A vessel made of ductile material FC 500 specially designed to withstand high pressure and provide the highest efficiency of oil separation.
Simple oil management, three-staged oil separator(models above RC2-1020), low-pressure-drop demister to ensure the minimum refrigerant dilution in the oil and maintain high oil viscosity.
Precise capacity control- The slide valve for capacity control is located in the compressor chamber. The slide valve is actuated by injection of pressurized oil into the cylinder from the oil sump as well as the bypass of oil through the solenoid valves in each oil lines with a pressure differential.
Perceptive protection modules- RC2 series screw compressors are equipped with PTC thermistors and motor protection module which could monitor discharge and motor coil temperatures as well as phase sequence and phase loss.
Accessories also include oil level switch to monitor the level of oil, pressure differential switch, and pressure relief valve for the optional application.
Adaptable with additional cooling- Liquid injection connection port located at the motor casing and in the compression chamber, oil cooler connection port, and a middle-pressure economizer connection port for customer’s desired application.
RC2 series compressors not only continue RC series compressors’ characteristics of high efficiency & reliability design mentioned above, but are also designed with the following newly added advantages to meet customers’ needs more adequately:
1. Design the fittest high-efficiency motor for respective refrigerant, operation condition and electrical power.
2. Dual capacity control of steps or continuous create more accurate and reliable mechanism (Option)
3. Part load effective economizer application.
Bitzer Screw Compressor
The condenser for a water-cooled screw chiller usually connects with the cooling tower for heat dissipation purpose.
The water cooled condensers work as the air-cooled condensers do, but they require two different steps to achieve the heat transfer.
First, the heat will be transferred from the refrigerant vapor into the condensing water by a water cooled shell and tube condenser.
Next, the temperature of the condenser water gets warm and will be pumped into the cooling tower where the unwanted heat is transferred to the ambient air.
TopChiller® condenser is featured by a shell and tube type heat exchanger that is easy for cleaning and its high quality helps the whole chiller work at an optimized efficiency level.
But there is another important issue, how to clean and maintain the water-cooled condenser?
The water cooled shell and tube type condenser is prone to scale formation after long-term use. If it is not disposed of in time, the scale will affect the heat transfer effect, resulting in an increase in the condensing temperature of the unit, which will result in a decrease in cooling capacity and an increase in unit power consumption.
Therefore, the condenser should be frequently cleaned of scale.
There are three main methods for preventing and removing scale:
A. Mechanical descaling method:
Mechanical descaling is a method of descaling a condenser of a steel cooling pipe with a soft shaft washer, and is particularly suitable for a vertical shell and tube condenser.
The methods of operation are as below:
1. The refrigerant in the condenser is withdrawn.
2. Turn off all valves connected to the condenser and the refrigeration system.
3. The cooling water of the condenser is normally supplied.
4. The umbrella-shaped gear scraper connected by the soft shaft washer is rotated and descaled from top to bottom in the riser of the condenser.
And the cooling heat generated by the friction between the scraper and the pipe wall is cooled by the circulating cooling water. Flushed dirt, rust and other dirt are washed into the pool.
In the descaling process, according to the fouling thickness of the condenser and the degree of corrosion of the pipe wall and the length of the used pipe, the hob with the appropriate diameter is selected.but the diameter of the hob selected in the first pass descaling is smaller than that of the cooling pipe.
The inner diameter should be appropriately small to prevent damage to the pipe wall, and the second round of descaling should be carried out with a hob close to the inner diameter of the cooling pipe. The descaling can remove more than 95% of the scale and rust of the condenser.
The method of mechanical descaling is to use the bevel gear-shaped hob to rotate and vibrate the hob during the rotation of the cooling tube, and remove the scale and rust in the condenser cooling tube, after the descaling is completed.
The water in the condensate pool is completely removed, and the dirt, rust and other dirt removed from the bottom of the pool are cleaned and refilled.
B. Chemical pickling and descaling method:
The condenser is cleaned with the prepared weakly acidic descaling agent to make the scale fall off and improve the heat transfer efficiency of the condenser.
The method of operation is:
1. Prepare the descaling solution in the pickling tank, start the pickling pump, and let the descaling agent solution circulate in the condenser tube for 24 hours. Under normal circumstances, the scale is basically removed after 24 hours.
2. After stopping the pickling pump, use a round steel brush to brush back and forth in the pipe wall of the condenser pipe, and rinse the scale and rust with clean water.
3. Repeat the cleaning of the detergent solution remaining in the tube with clean water until it is completely clean. The chemical pickling and descaling method are suitable for vertical and horizontal shell and tube condensers.
C. Electromagnetic water descaling method:
The working principle of the electronic magnetic water device is to dissolve calcium, magnesium and other salts in the cooling water flowing through the condenser in water in a positive and negative ion state at normal temperature.
When the cooling water flows through the transverse magnetic field of the magnetic water at a certain speed, the dissolved calcium and magnesium ions receive the induced electric energy, the charge state changes.
And the electrostatic attraction between the ions is disturbed and destroyed, thus changing its The crystallization condition makes the structure of the crystal lose.
The tensile and compressive resistance is reduced, and the hard scale with strong adhesion cannot be formed, and the loose sludge is discharged with the flow of the cooling water.
This descaling method can effectively prevent the generation of a new scale, and can also remove the original scale, because the ion loses the scaleability after using the electronic water magnetizer, which loses the protective effect on the original scale.
In addition, the magnetized cooling water has a certain amount of inductive electric energy.
At the same time, due to the different expansion coefficients of the steel pipe and the scale in the condenser, the original scale gradually cracks, and the magnetized water invades the crack without interruption.
This will also destroy the adhesion of the original scale makes it gradually loose and falls off on its own and is continuously taken away by the circulating cooling water.
The descaling method of the electronic magnetic water device is simple and easy to operate, has low labor intensity, and performs descaling and prevention of scaling without affecting the normal operation of the refrigeration system.
The significance of descaling and energy saving:
Once the condenser is scaled, the thermal resistance increases, so the thermal resistance increases, and the heat transfer coefficient value decreases.
Because the condensation temperature is inversely proportional to the heat transfer coefficient, the condenser temperature rises and the condensing pressure increases accordingly.
The more serious the fouling of the condenser, the more significantly the condensing pressure is increased, so that the power consumption of the refrigerator is increased, and the power consumption of each operating device of the refrigeration system is correspondingly increased, resulting in a waste of electric energy.
4. Oil Separator
Some oil in the chiller will come out when the refrigerant is compressed by the compressor.
If the oil is not removed in time, it will flow through cooling components after leaving the condenser, which will hinder heat transfer and even reduce the capacity of the evaporator and condenser.
The oil separator is to make the oil detached from the refrigerant and minimize the amount of oil flowing in the water-cooled screw chiller. As a result, it is particularly crucial to prevent oil from gathering in the unit.
Water cooled screw chillers manufactured by TopChiller® contain oil separators that are smaller in size and fewer moving parts, which make them more effective in the removal of oils in the refrigerant and also lower in terms of failure rates.
A double screw compressor integrated with an oil separator maximizes the efficiency of the water cooled screw chiller.
The evaporator of water cooled screw chiller is where the chilled water is formed.
In a shell-and-tube evaporator, the liquid refrigerant at low pressure enters the shell and flows through the tubes, absorbing heat from higher-temperature water that flows through the tubes.
When the water has reached a particular temperature, it will send the heat back to the refrigerant in the evaporator and get evaporated.
In the meantime, the water temperature cools down when the heat is extracted by the refrigerant.
Generally, the evaporator is installed between the compressor and the expansion valve.
Water cooled screw chillers manufactured by TopChiller® are featured by shell and tube heat exchanger, and also provides options for plate heat exchangers. All are suitable for R22, R407c, R134a, R404A and many other refrigerants.
Here we must pay more attention to one important point. As all know, for regular water cooled screw chiller, we are using tap water or well water as the cooling water source, also the inlet and outlet chilled water also tap water or fresh water.
But sometimes there are lots of end-users using sea water, marine water as the water cooling sources, to cool down marine water, brine water, sulfuric acid or other chemical liquid.
In this case, the regular shell and tube heat exchanger can’t be used due to all these coolant and liquid are with strongly corrosive.
So we must go for a titanium material shell and tube heat exchanger as an ideal solution for a chemical factory, seawater cooling, marine or brine chiller and shrimp or seafood hatchery.
Titanium material shell and tube heat exchanger can cool the corrosive liquids include hydrochloric acid, sulfuric acid, nitric acid, chromic acid, acetic acid and hydrofluoric acid, seawater, marine or brine water directly.
Please check below titanium material shell and tube heat exchanger:
Please contact TopChiller refrigeration expert to customize your screw chiller.
6. Expansion Valve
The expansion valve connects the evaporator and condenser to keep the pressure difference between the two sides, and controls the fluid flow of the refrigerant into the evaporator and eventually into the compressor as well.
The pressure has to be reduced if we need to reduce the temperature and as thus, some kind of restriction is required for this to take place.
Expansion valves enable users to regulate the capacity load based on the requirements of the production process.
TopChiller® designed thermostatic expansion valves for water cooled screw chillers to ensure the unit is operating at the optimized level.
The thermostatic expansion valve is a restriction device which can adjust the refrigerant pressure and maintain superheat at the outlet of the evaporator.
What’s more, it can achieve stable evaporator temperature as well as maintain the pressure according to the required saturation temperature by simply employing an evaporator pressure regulating valve to the chiller.
Both air-cooled chiller and water cooled chiller consist of compressor, evaporator, condenser, oil separator and expansion value. What are the advantages of water-cooled screw chillers compared to air cooled screw chillers?
The Advantages of Water Cooled Screw Chiller Compared to Air Cooled Screw Chiller
Both kinds of chillers operate based on similar principles to complete the heat transfer but they use different components to cool the condensers.
Water cooled chillers use water consumption while air cooled chillers need air.
The major difference is that water cooled screw chiller requires a cooling tower and the water cooled screw chiller is worth considering as it has the following advantages compared to air cooled screw chiller.
1. Quiet Operation
Water cooled screw chillers are more silent than air cooled screw chillers when they are in operation.
Noise in some workplaces can be annoying, especially in hospitals or other business offices. Air cooled screw chillers generally create more noise because of their fans.
2. Environment Adaptability
As water cooled screw chillers do not need ambient air while they are operating, there are no strict requirements for the ventilation conditions around the unit.
If the ventilation is minimal around an air cooled screw chiller, the operating performance will be badly affected because they rely on the ambient air for cooling.
Therefore, water cooled screw chillers are the better choice in places where the air recirculation is restricted.
For the air cooled screw chillers, they require open areas such as roof, parking lot, or ground level area to utilize the air for cooling.
3. Energy Efficiency
Although air cooled screw chiller may cost less than water cooled screw chiller in terms of the purchase price as water cooled screw chillers require cooling towers and water pumps, etc.
However, the compressor costs and the energy consumption costs for air cooled screw chillers are generally higher due to their basic operating design.
However, water cooled screw chillers are more energy efficient as water cooled screw chillers are equipped with cooling towers that allow the cooling system to operate at low consumption costs.
Water-cooled screw chiller VS air-cooled screw chiller:
The air-cooled screw chiller unit is suitable for medium and small systems with tight water sources in the region due to the longer the annual operating hours, the more advantageous the air-cooled refrigeration unit is.
Also the annual comprehensive cost of the air-cooled chiller unit is lower than that of the water-cooled chiller system.
But water-cooled chiller If the system is managed and the water supply is controlled below 3%, the initial investment of the air-cooled refrigeration unit compared with the water-cooled refrigeration unit is difficult to recover.
This article is a comprehensive analysis and comparison of air-cooled/water-cooled chiller units, and I hope to be useful to everyone.
First, the comparison of two chiller units
1. The water-cooled chiller must be equipped with a cooling tower. For the open cooling circulating water system, since the cooling water absorbs heat, it is in contact with the air, and CO2 escapes into the air.
The dissolved oxygen and turbidity in the water increase, resulting in a cooling circulating water system. Big problems: corrosion, scaling, bacterial growth, sludge.
If the water quality is not treated, the refrigeration equipment will be seriously damaged, and the heat exchange efficiency will be greatly reduced, resulting in a waste of energy.
Therefore, it is very important to carry out corrosion inhibition, scale inhibition, sterilization and algae treatment on the water system.
The water-cooled chiller cooling system must be equipped with an electronic water treatment device or a strong magnetic water treatment device.
Otherwise, the heat dissipation efficiency is too large. The longer the use time, the worse the system effect. The annual water treatment cost is high, and the effect cannot reach 100. % descaling.
The quality of cooling circulating the water is the key. The processing of cooling circulating the water is divided into physical and chemical methods.
2. Water-cooled/air-cooled chillers can be used on small systems. Most of the large screw chiller units are water-cooled.
The initial investment in water cooling is less than that of air cooling. But with the cooling tower and the machine room\electronic water treatment instrument, etc., there is no place to go!
Besides, in terms of long-term operation, the cooling efficiency of water-cooled chiller units will decrease relatively, and the air cooling will drop. Very small.
3. The air-cooled screw chiller adopts air cooling mode, which eliminates the cooling tower, cooling water pump and piping system that is essential for the cooling water system, avoids condensation of the condenser, blockage of water pipes, and saves water resources in areas with poor water quality.
It is the most economical and simple machine for maintenance and repair of the air-cooled screw chiller.
The air-cooled chiller has a slightly higher one-time investment than the water-cooled chiller, but the annual operating cost is lower than that of the water-cooled chiller.
The construction cost of the equipment room is the least in various air-conditioning cold and heat source systems, and the maintenance cost is about half of the cost of water-cooled screw chiller.
The air-cooled chillers are louder of in noise level than water-cooled chillers and can only be installed outdoors. Most of the water-cooled chiller units are installed at the basement.
4. The service life of water-cooled screw chiller is 15-20 years; the service life of air-cooled screw chiller is around 6-11 years.
The COP value represents the energy efficiency ratio of the air-cooled chiller. The water cooled screw chiller refrigeration efficiency is higher than the air cooled screw chiller.
The higher the cop value, the higher the air cooling efficiency and the better energy saving. (COP = air cooling nominal cooling capacity / compression input power).
Air cooled screw chiller’s COP value is 3.44; while water-cooled screw chiller COP value is 5.2. This is a big difference in the cost of cooling performance.
2. The technical and economic comparison of the air cooled screw chiller and water cooled screw chiller units
Considering that the number of air-cooled condensers of large refrigeration units is too large, it is usually difficult to arrange.
On the other hand, too small water-cooled screw chiller units are also unfavorable for use, so for medium-sized air-cooled screw chiller units and the same amount of cooling. Water-cooled chiller units are compared.
Now compare a model of water-cooled screw chiller unit with the same air-cooled screw chiller unit with main unit and evaporator:
The annual operating time of the screw compressor is 1000 hours to 3000 hours, and the annual running time of the cooling tower and the pump is 1400 hours to 4200 hours.
For summary, The initial investment of air-cooled screw chiller units is relatively high, and the power consumption per unit of refrigeration capacity is also slightly higher than that of water-cooled screw chiller units.
However, the annual comprehensive cost of air-cooled chiller units is basically the same as that of water-cooled units. The longer the annual running time of the screw chiller, the more favorable it is to the air-cooled chiller unit.
The initial investment recovery period of the air-cooled screw chiller unit compared with the water-cooled screw chiller unit is shorter.
The amount of water replenishment of the water cooling unit is an important factor affecting its cost. Strengthening maintenance management and reducing water consumption are important aspects of reducing the cost of water-cooled chiller units.
Industrial Applications of Water Cooled Screw Chiller
Different types of screw chillers are used in various industries. However, let’s talk about the most common applications of water cooled screw chillers.
Heating, Ventilation and Air Conditioning (HVAC) systems are used to dehumidify the air and to cool the temperature to create a comfortable interior environment despite the different external conditions.
Water cooled screw chillers have become an essential part in HVAC systems and are being used in various facilities, including restaurants, hospital, hotels, office buildings, supermarkets, etc.
TopChiller® water-cooled screw chillers are suitable for being a key component for HVAC systems. As a long-time chiller supplier for many medical facilities, TopChiller® water-cooled screw chillers can provide an exact cooling effect as required.
Whether you are in need of a water-cooled screw chiller for an HVAC system, your facility will be comfortable and the occupants can find the peace of mind even in the hottest time of the day.
2. Milk Cooling
Keeping milk at a cool temperature during processing is very important. The milk could go bad easily in a short period of time if it’s not stored in a certain environment.
Therefore, chillers are very popular for milk cooling as they can extend the storage life before the milk is transported to the market for sales.
The milking machines will automatically pump the milk into a storage tank for pasteurization which will generate heat during the process.
Water cooled screw chillers manufactured by TopChiller® are able to remove heat from pasteurization and reduce the temperature of the milk to an appropriate point. Maintaining milk at a low temperature prevents the milk from deteriorating.
3. Die Casting
Die casting is a process in which the molten metal is pushed into a steel mold under high pressure into mold cavities.
In the metal casting process, there are basically five steps involved: clamping, injection, cooling, ejection, and trimming.
The cooling is required when the molten metal is injected into the mold and the metal will be in final shape after it is solidified and cooled down.
TopChiller® water cooled screw chillers are efficient in cooling die casting machines and can provide premium reliability and achieve high efficiency at all operating conditions.
Excellent design and high value make water cooled screw chillers supplied by TopChiller® are being used by many industrial companies from different countries all over the world.
Trouble Shooting of Water Cooled Screw Chiller
It is really annoying if your water cooled screw chiller always alarm or error happens. Let’s study some common alarm and error we always meet:
1.Low exhaust temperature, oil level protection
Phenomenon:After the power is turned on for about 1~2 minutes or 2~3 minutes, the oil level protection occurs, the unit alarms and stops; when the oil level is protected, the oil does not see the oil in the compressor oil sight glass; the exhaust temperature of the unit is always up, only 40 Around °C
Analysis: Before the start-up, the oil heater is not heated to more than 8H, so that all the oil in the compressor accumulates in the evaporator, resulting in poor heat exchange effect of the evaporator, easy to bring liquid with suction, so the exhaust temperature is low every time.
The low gas temperature affects the separation effect of the oil separator, which ultimately causes the compressor to be oil-deficient. Also need to check for oil leaks.
Disposal: Recycle or release all the refrigerant and oil in the system, then refill the refrigerant according to the factory procedures, add lubricating oil; the unit runs normally.
The main reasons for the protection of the oil level of the water-cooled screw chiller unit are:
A. Oil leakage. Phenomenon: Turn on the machine and do not see the oil level when stopping.
B. The oil level switch is damaged. Phenomenon: start-up, the oil level is full when stopping, oil level protection occurs;
C. There is too much refrigerant in the oil. Phenomenon: The oil level is full when starting, and the oil level is not seen after starting. After a long-term shutdown, or a long-term power failure, the electric heating time is not enough.
2. The safety valve is opened
Phenomenon: The water-cooled screw chiller unit safety valve is opened.
Analysis: There are multiple water flow switch protections on the touch screen. The initial judgment is that the cooling water pump suddenly stops, the high pressure rises, and the opening pressure of the safety valve is exceeded.
Disposal: Replace the safety valve and refill the refrigerant. After starting the machine, the parameters are basically normal, but the high pressure is high and the cooling water flow is small. It is also the reason for the safety valve to open.
There are two cases in which the water-cooled screw chiller unit safety valve is opened:
1. The evaporator safety valve is opened. Generally occurs when the unit is in shutdown:
During the transportation of the screw chiller unit, it is exposed to the sun;
The screw chiller unit was installed on the roof without any shading measures.
The safety valve is not tested or updated for a long time.
Cause: In this case, the refrigerant pressure exceeds the opening pressure of the evaporator safety valve. The safety valve is open.
2. The water cooled condenser safety valve is opened:
Occurs when the unit is turned on: the high voltage rises rapidly due to sudden causes.
A. The cooling water pump is powered off;
B. A cooling tower fan is powered off;
C. The cooling water system is dirty.
Reason: In this case, the refrigerant pressure will suddenly rise, the high-pressure protection will not be able to move, or the action will be high. The high pressure has exceeded the opening pressure of the safety valve.
Special Note: After the unit safety valve is opened, the copper tube of the evaporator may be cracked due to a large amount of leakage of the refrigerant. A water ingress accident occurred. The safety valve is a safety device and the safety valve must be tested every year as required.
3. Water cooled screw chiller unit cannot be loaded
Phenomenon: The water cooled screw chiller unit cannot be loaded during operation, and it is always maintained at 50% operation, and the chilled water temperature cannot be reduced.
Analysis: The high pressure of the screw chiller unit was found to be above 17kG. According to the control of the unit, at this time, in order to prevent the high pressure from continuing to rise.
The screw chiller unit is actively unloaded, and it is normal from the signal of the solenoid valve. The temperature difference between the cooling water reaches 10 ° C or more. The cooling water pump has a small flow rate.
Handling: Replace the water pump. The screw chiller unit is operating normally.
There are many reasons why the screw compressor is not loaded, and the organic group actively unloads, which has the reason for the compressor itself.
High-pressure unloading problems are more common, mainly due to high condensing pressure of the unit. Also need to pay attention to the compressor oil circuit blockage.
4. Water cooled screw chiller unit cannot be loaded
Phenomenon: There are two main situations
The unit has high voltage protection within 3 minutes of starting;
The unit has high voltage protection during operation;
Reason: There are many reasons, and it is necessary to check them one by one, but the most common cause is the problem of the water system:
The cooling tower is dirty and the heat exchanger copper tube is fouled.
The cooling tower has a small capacity.
Small water flow;
The screw chiller unit is at the highest point on the roof and the water pipes cannot be drained.
The screw chiller unit electronic expansion valve is stuck;
The maintenance unit has a short vacuum time when flushing the refrigerant.
Note: After scaling, the performance of the heat exchanger is very large. It is difficult to clean the dirt by the method of passing bubbles. It is necessary to use the syrup.
5. Water cooled screw chiller low-pressure error/alarming
Phenomenon: There are two main situations:
The unit has low voltage protection within 3 minutes of starting;
The unit has low voltage protection during operation;
Reason: There are many reasons, and it is necessary to check them one by one, but the most common cause is the problem of the water system:
The heat exchanger copper tube is fouled.
The unit is at the highest point on the roof and the water pipes cannot be drained.
Small water flow;
The unit electronic expansion valve is stuck;
The method of starting the refrigerant and adding the refrigerant is very wrong. When flushing the refrigerant, it is often added first. After adding it, add the refrigerant by means of booting. When discharging refrigerant and adding tank refrigerant, the chilled water pump must be turned on, otherwise the shell and tube may be frozen.
Water-cooled screw chiller debugging process and troubleshooting
The water-cooled screw chiller is mainly composed of a semi-hermetic screw compressor, a shell and tube condenser, a dry filter, a thermal expansion valve, a shell and tube evaporator, and an electric control part.
When the operating temperature of the water cooled screw chiller unit is low in winter (below 0 degrees), it is recommended to increase the anti-freezing measures to protect the operation of the unit.
The screw chiller unit must drain the water in the heat exchanger and the outdoor water pipe during the winter period, otherwise it is easy to freeze. The screw chiller unit is damaged.
Because the screw water chiller unit is not operating in the winter, it is recommended to drain the water in the water line, or add enough ethylene glycol solution to the line as a precautionary measure to refill the water when the next operating season arrives.
First, the water cooled screw chiller normal operating status
The height of the refrigerant liquid level: R134a water-cooled screw unit evaporator liquid level: Under the condition of stable working conditions and water flow, the height of the liquid surface is just the best.
Exhaust gas temperature: Under nominal conditions, the exhaust gas temperature should be in the range of 45 °C-65 °C (R134a) and 50 °C-75 °C (R22) (exhaust temperature and evaporator and condenser outlet temperature) related).
Compressor oil sight glass: The high oil sight glass is full, and the oil level of the low oil sight glass is not lower than 1/2 of the oil sight glass.
High and low pressure values: high pressure value is not higher than 1.14MPa (R134a) and 1.8MPa (R22), low pressure value is not higher than 0.18Mpa (R134a) and 0.3MPa (R22), oil pressure difference is 250kPa, suction and exhaust pressure difference It is 0.4 MPa.
Saturation pressure: At any time, the corresponding saturation pressure at the inlet temperature of the evaporator and condenser should not exceed the design pressure of the container. Otherwise, the safety valve will start to jump and the refrigerant will leak out (the water temperature should not exceed 45 °C).
Exhaust superheat: Refrigeration exhaust superheat is between 10 °C and 20 °C, and the suction superheat is 0.5 °C – 3 °C. Adjusting the suction superheat depends on the exhaust superheat and the evaporator level.
Outlet water temperature: The evaporator outlet water temperature should be controlled within the range of 3-20 °C; the condenser outlet water temperature should be controlled within the range of 21 °C-45 °C.
Voltage and current: The maximum allowable phase voltage imbalance is 2% and the phase current imbalance is 10%. The phase voltage imbalance is greater than 2% and must not be turned on.
Second, debugging common troubleshooting problems
Suction superheat adjustment: Suction superheats = suction temperature – evaporator saturation temperature on the outlet side of the evaporator. Adjusting the suction superheat depends on the exhaust superheat and the evaporator level.
Suction superheat mainly determines whether the expansion valve selection is appropriate.
The purpose of adjusting the suction superheat is to prevent liquid shock; to fully exert the performance of the evaporator.
Inhalation superheat target value: 0.5 ~ 3 °C.
The suction superheat is lower than the target value, indicating that the expansion valve opening is large, which easily leads to liquid hammer.
If the suction superheat is higher than the target value, the expansion valve opening is too small, which will result in low evaporator utilization and impact on capacity.
If the suction superheat is too high, the expansion valve opening may be too small, which may cause low pressure to be too low.
Low-voltage fault of the unit: R134a low-pressure alarm value is 0.18Mpa. R22 Low-pressure alarm value is 0.3Mpa Unit low-pressure alarm Possible causes:
The electronic (thermal) expansion valve is faulty or has a small opening.
The compressor suction shut-off valve or the liquid line valve is closed (on alarm).
The sensor is damaged or the collected data does not match the actual value.
Differential pressure alarm: In order to avoid the shortage of oil supply to the compressor, sufficient pressure difference must be ensured during the operation of the unit to ensure normal return of the compressor.
The oil level is too low: during the operation of the unit, attention should be paid to the state of the oil mirror of the press, the state of the return line and the liquid level of the evaporator, and the liquid level of the evaporator and the superheat of the exhaust.
Pay attention to the following points when the oil level of the press oil sight glass drops:
Observe the high and low pressure side view liquid mirror of the return line, whether the high pressure side oil mirror has oil flowing quickly, and whether the low pressure side glass returns oil.
If it is found that the oil flow is not smooth, it is necessary to check whether the return line of the return line is not open or the opening is too small;
Observe whether the liquid level of the evaporator is suitable.
It is usually better to use the liquid level to flow over the first row of heat exchange tubes. If the low pressure cannot return the oil because the liquid level is too low, the evaporator can be opened and the evaporator level can be increased by adjusting the superheat degree. rise.
If the oil or exhaust temperature is too low due to the liquid suction caused by the liquid level being too high, the opposite adjustment is made.
Observing the system pressure difference, the pressure difference is too small can also lead to insufficient oil return. The pressure difference can be established as soon as possible by adjusting the water temperature.
Undercooling: Undercooling = liquid saturation temperature – condenser outlet refrigerant temperature
The degree of undercooling mainly determines whether the refrigerant filling amount is appropriate.
The purpose of adjusting the degree of subcooling is to ensure that the refrigerant entering the expansion valve is a liquid and prevent the liquid from flashing before the expansion valve.
Undercooling target value: 4 ~ 6 ° C
If the degree of subcooling is lower than the target value, the refrigerant may be less filled or the number of supercooled tubes may be less.
The refrigerant may be added or the supercooled pipe may be added. If the degree of subcooling is higher than the target value, the refrigerant may be excessively filled and the refrigerant may be properly discharged.
Why TopChiller® Can Be a Reliable Supplier for Water Cooled Screw Chillers?
1. Optimum Performance of Water Cooled Screw Chiller
TopChiller® water cooled screw chillers are helpful to improve energy efficiency, and by using a semi-hermetic dual screw compressor, these chillers are able to realize step-less capacity control.
Working at high noise levels will affect the health of the workers and it’s also important that companies should focus on noise reduction, especially in workplaces sensitive to sounds.
Running noise created by TopChiller® water cooled screw chillers is also very low as there is little friction in the compressor.
The compressor can serve for a long time thanks to the high-quality oil separator inside.
The safety protection devices are also the main reason that TopChiller® chillers have a longer lifespan than other brands of chillers.
Their features include but are not limited to the following functions: overheat protection, overcurrent protection, over-pressure protection, over-temperature protection, flow rate protection, anti-freezing protection, low-level coolant protection.
These protection methods prevent the chillers from being damaged by overload situations and the chillers can maintain smooth operation and long service life.
2. Decades of Professional Experience in Screw Chillers
TopChiller® was founded in 2003 and has been specialized in the research and sales of industrial cooling equipment and replacement parts since then.
Decades of expertise has helped TopChiller® earn clients from over 58 countries and regions. All water-cooled screw chillers manufactured by TopChiller® are CE marked and comply with standards products sold in Europe countries.
TopChiller® also earned a series of awards conferred by the government in China for energy saving and technology innovation.
3. Worry-Free After-Sales Service
As the chillers are used for the production every day, it’s very crucial to make sure they are operating smoothly without malfunction issues.
If by any chance the unit goes out of order, quick technical assistance must be available on hand to solve the problem. At TopChiller®, we have a professional team in charge of quality inspection before the shipment and maintenance support.
For every chiller purchased from TopChiller®, its quality must be carefully checked before shipment to ensure the client will receive a satisfying chiller.
In the meantime, TopChiller® also provides a comprehensive range of services for pre-sales questions and after-sales issues, covering everything from product inquiries to maintenance support.
All clients can still expect professional and personal care and reliable services from our support team at any time.
All of our water cooled screw chillers come with an 18-month warranty and we are always ready to offer lifetime technical support to our valued clients.
4. Customizable Water Cooled Screw Chillers
There are many factors involved when selecting the right chiller for industrial production. Different chillers in different sizes have cooling capacities.
It’s very important to assess if a chiller can just fit your specific requirements and help bring maximum profitability for the production process.
TopChiller® has developed a wide range of water cooled screw chillers that also come with various specifications for the customers to choose.
In the meantime, we also accept customization requests to help your business reduce operating costs and create more profits.
To select the right chiller, you have to make sure that you find a reputed manufacturer of water cooled screw chiller like TopChiller®.
Before ordering the right chiller, you need to calculate the amount of water which is required to be chilled, then decide on the requirement.
In this way, you can find the right chiller and as a result, your production will achieve efficiency to the maximum level.
TopChiller® is committed to sustainable development and the concept has been integrated into our corporate culture.
The water cooled screw chillers supplied by TopChiller® are energy efficient and suitable for MRI, CT, milk cooling, die casting, and many other industrial applications.
The cooling capacity of our premium water cooled screw chillers ranges from 40 Ton to 680 Ton and their operating sound levels are very low in all conditions.
TopChiller® water cooled screw chillers are widely used by all kinds of industrial companies all over the world. If you are not sure which chiller you should choose for your system, our chiller experts are always here to help.
Please contact us right away by sending an inquiry to check what your system requires. Choosing between water-cooled and air-cooled screw chillers is not an easy decision.
However, with decades of expertise, we will help you find which one is the best option for your company.
TopChiller having enough confidence that you will find using our water cooled screw chillers will help a lot with production efficiency and cost reduction.