Screw vs Scroll Chillers: Which One Is Better?

Are you still worrying about choosing between a scroll chiller and a screw chiller? Whether you are looking to purchase a household chiller or an industrial chiller, this article will share you with a detailed explanation of the differences between the two. To help you select a chiller unit that is more suitable for your industry

Scroll Compressor vs Screw Compressor: Which will You Choose?

The main difference between scroll chillers and screw chillers lies in the different types of compressors they use. The following are the differences I want to share:

Scroll Compressor Working Principle

One spiral-shaped scroll plate is firmly fixed, while the other slowly rotates around its centre. As the discs rotate, the space in the middle is gradually squeezed smaller and smaller.

When inhaling, the crescent-shaped space on the outermost circle expands, allowing the low-pressure refrigerant to enter. The moving disc continues to rotate, and the space gradually shrinks, causing the gas to be slowly compressed. Both the pressure and temperature rise. When it reaches the innermost part, the high-pressure gas rushes out from the central exhaust port.

Scroll Compressor Advantages And Disadvantages

Scroll Compressor Advantages

• Ultra-quiet operation:The noise level during operation can be as low as 48 decibels, equivalent to the sound of turning pages in a library. If you use it beside your office or store, it basically won’t disturb your daily business operations.
• It occupies an extremely small area: Most are less than 4 square meters in volume. It can also be stuffed into a closet or a corner, eliminating the need to build a dedicated machine room. For small shops or renovation projects, saving space means saving money.
• Energy conservation: It can intelligently shut down idle compressor pumps, automatically adjust pressure, and avoid excessive energy consumption. Over the long term, the electricity bill is much lower than that of traditional models.
• Low maintenance cost: Few internal parts and a simple structure. The modular design makes installation like building with blocks and requires fewer accessories.

Scroll Compressor Disadvantage

• Repair: Once a problem occurs, the entire machine basically needs to be replaced. Unlike screw machines, which can undergo local maintenance. You need to consider alternative plans in advance for this point.
• The initial investment is relatively high: additional accessories such as crankcase heaters and intake pipe accumulators are required. The manufacturing process is also complex, so the price is higher than that of ordinary models when purchased.
• Limited high-load capacity: The gas leakage problem makes it difficult to achieve an ultra-high compression ratio. If you need to operate at full capacity for a long time, you may not be able to handle it.

Screw Compressor Working Principle

Let’s continue to talk about the core of the screw chiller – the working principle of the screw press.

The core is the male and female rotors. In a screw chiller, the motor directly drives the male and female rotors to move. The “Yin and Yang” mentioned here refer to two screws with complementary shapes: the teeth of the male rotor protrude, while the tooth grooves of the female rotor are deeper, resembling the two halves of a jigsaw puzzle.

When the rotor rotates to a specific position, the tooth grooves open, and the low-temperature and low-pressure gas enters the empty grooves. The space is getting smaller and smaller, and the gas is gradually compressed into high temperature and high pressure. Finally, turn to the exhaust port.

Screw Compressor Advantages And Disadvantages

Screw Compressor Advantages

• Suitable for extreme conditions: Whether your workshop has a high temperature of 40℃ in summer or a low temperature of -20℃ in winter, or it is a factory with slightly corrosive special gases, you can blindly purchase a screw chiller. It has a strong adaptability to harsh working conditions.
• Structural simplification: The rotating screw compressor has fewer moving parts than traditional machines. This means that for you, the internal friction loss of the machine is small, and the potential failure points are significantly reduced. Although repairing a screw compressor usually costs a lot, its simplified structure makes it difficult to break down.
• Quietness:You should pay attention to the working environment. Noise is a big problem. ChillerOne screw compressors optimise the airflow path and have soundproof wrapping. When running, the sound is much softer and can usually be controlled at a relatively low decibel level. It has a smaller impact on your factory and the surrounding areas.
• Long service life:This is attributed to its efficient working mode and fewer moving parts. The core lies in the fact that screw compressors generate relatively less heat, have less mechanical stress, and thus wear out naturally more slowly. With precise processing and high-quality materials. A properly maintained screw compressor can last you for over a decade. Bring you long-term investment returns.
• Low consumption of lubricating oil: Modern screw compressors have made great efforts in the design of their lubrication systems, and the amount of oil used is precisely and efficiently controlled. Reduced the fuel consumption cost during operation. It also saves you the trouble and cost of waste oil treatment and is more environmentally friendly.
• All-weather continuous operation:Inherently designed for long-term continuous operation. High heat dissipation efficiency. Your factory operates 24 hours a day without a break. Choosing it is the most suitable option. Usually, the capacity of a single unit is powerful enough, simplifying the configuration.

Screw Compressor Disadvantages

• High initial investment:To be honest, the technical content and structure of screw compressors determine that their purchase price is higher than that of scroll compressors. It is suggested that before you hesitate to purchase this device, you calculate clearly whether the long-term maintenance cost savings and the long service life can cover this price difference.
• Difficult to maintain and service:The advantages mention that it is reliable, but that doesn’t mean it can be left unattended. On the contrary, its precise structure requires that maintenance be standardised and in place. Regular professional maintenance is indispensable. And it is best to have it operated by a professional technician certified by the manufacturer or with experience. Operators need to master multiple types of knowledge, such as refrigeration, electrical, and water systems, simultaneously. If you fiddle around on your own or seek help from unreliable people, problems are likely to arise.
• Large volume: To achieve high power and efficient heat exchange, the condenser and evaporator of screw compressors usually adopt a shell and tube structure with a relatively large volume. Coupled with the already relatively long compressor body, the overall floor space occupied will be considerable. If your computer room space is tight or you need a flexible layout. Planning the placement in advance can save you a lot of trouble in your subsequent work.

Screw vs Scroll Chillers: Refrigeration Capacity

Scroll water chillers have a cooling capacity that mostly ranges from 3kW to 200kW, and most models have a cooling capacity of less than 30 tons. If you still want to increase its cooling capacity, the scroll chiller also supports parallel operation. However, this will increase your budget.

Screw-type cooling capacities have a wide range, covering from 100kW to 3000kW. Parallel connection is unnecessary as it costs more money and takes up more space.

Screw vs Scroll Chillers: Operating Noise

Scroll chillers have more obvious advantages in noise control. Our normal conversation sounds around 60 decibels. During operation, the noise of most scroll water chillers is between 50 and 65 decibels. So when it works, it’s basically just like our daily conversation, very quiet. If you want to purchase a chiller for your office or home, a scroll type basically won’t make you feel noisy. It will become your more comfortable choice.

Screw chillers are generally quieter. The standard model is usually within the range of 70 to 85 decibels. Especially for air-cooled screw chillers, once the fan is turned on, the noise will be louder than that of water-cooled screw chillers. For places with quiet environments, it might be a factor that needs to be taken into consideration.

Screw vs Scroll Chillers: Service Life

Scroll chillers are suitable for intermittent operation and can be used on average for 8 to 12 years. Screw chillers can operate continuously, usually for 15 to 20 years, which is not a small difference. Of course, this number is not fixed. The key lies in how you use and maintain it.

Which One Has A Higher Cost, The Screw Chiller or The Scroll Chiller

Cost should be comprehensively judged from two aspects:

Purchase Cost

Let’s start with the purchase cost. The scroll chiller has a simple structure and a medium cooling capacity. The price is usually lower than that of screw machines of the same specification, which puts less pressure on your initial procurement. Screw chillers, on the other hand, are suitable for large cooling capacity demands and have a higher unit price. However, in the long run, its efficiency advantage can spread out the cost.

Operating Cost

Another cost you need to consider is the cost generated during the operation process. The scroll chiller has good energy efficiency at partial load and is more energy-efficient. However, if your factory operates at full capacity throughout the year, screw compressors, with their more stable compression efficiency, will cost less electricity. Especially in high-temperature environments, screw chillers can be even more energy-efficient.

If you are short of funds in the early stage and only want to purchase a chiller for use in some small areas, it is recommended that you choose a scroll chiller, which is sufficient. If you are planning to purchase an industrial chiller that operates continuously in a factory, in the long run, a screw chiller is well worth your investment.

Screw vs Scroll Chillers: Application Adaptability

• Scroll Chillers: If you don’t keep it on for a long time every day, say less than 24 hours, it’s quite suitable to use it. It has a compact structure and starts up quickly. The pressure is low when restarting after a shutdown, making it suitable for situations where your production rhythm is not so tight.
• Screw chillers:Suppose you need continuous and stable cooling, especially when the cooling capacity requirement exceeds 30 tons. It can withstand long-term high loads and still maintain stable efficiency. However, it starts up more slowly and has a higher downtime cost, making it suitable for scenarios in your factory where it must operate continuously for 24 hours.

Do Screw Chillers And Scroll Chillers Take up A Large Area

The scroll chiller takes up little space and is suitable for use as a household chiller. Screw-type water chillers are relatively large in size and are mostly used in large factories.

Screw vs Scroll Chillers: Application Field

Scroll Chillers Applications

The Medical Field

It is particularly suitable for the temperature control requirements of hospital operating room constant temperature systems, cooling of medical equipment (such as heat dissipation of MRI equipment).

Pharmaceutical Equipment

Scroll chillers adopt hermetic scroll compressors with continuous, low-pulsation compression, delivering ±0.3~±0.5℃ precise temperature stability, low vibration, quiet operation, compact footprint and low maintenance cost.

Laboratory

Cell culture incubators and chemical reagent constant temperature baths in biological laboratories require precise temperature control.

Commercial Building

Central air conditioning systems are particularly suitable for small and medium-sized commercial complexes, such as distributed air conditioning units in office buildings. Compared with screw machines, scroll machines consume less energy at partial loads and are suitable for the fluctuation of customer flow in shopping malls.

Household

Household small water chillers need to pursue a quiet effect, and the scroll type has less noise.

Food Processing

The quick-freezing tunnel of a small cold drink factory and the food preservation system of a central kitchen.

It should be noted that if the cooling capacity exceeds 150kW or continuous operation for more than 8 hours is required, screw chiller models may need to be considered.

Screw Chillers Applications

Automobile Manufacturing

The body stamping die requires a large amount of cooling water to remove the instantaneous high temperature and ensure the forming accuracy of the steel plate. The large cooling capacity output of screw compressors is particularly suitable for this continuous high-load demand.

Brewing And Food Processing

The screw can provide a stable, low-temperature environment for brewing alcoholic beverages. Screw chillers are also suitable for the rapid cooling of large-scale food quick-freezing tunnels and filling lines after pasteurization.

Food Packaging

The high-speed aseptic packaging line requires immediate cooling of the sealing area to prevent the plastic film from deforming and affecting the sealing performance. The rotary screw chiller can effectively deal with it.

Aerospace

When the composite material components are solidified and formed, the molds need to be cooled at a constant temperature for a long time. In large-scale wind tunnel experiments, simulating extreme airflows also requires a powerful cold source. Screw compressors can withstand these high-intensity and long-duration working conditions.

Construction Industry

For temporary centralized cooling systems, screw compressors are also a reliable choice, especially when the construction site is far from the municipal pipeline network.

How to Choose A Suitable Industrial Chiller

Air-cooled And Water-Cooled Options

Choose which heat dissipation method you want. This matter is directly related to the subsequent costs, installation difficulty, and long-term operation effect.

Air-Cooled Chiller

Its condenser dissipates heat by blowing air through a fan, and the entire system is independent. You don’t need to connect an external cooling tower or water pump, and it’s particularly worry-free to install. Especially the air-cooled scroll chiller. It’s still small in size.

However, it also has a drawback, which is that the heat exchange efficiency of air is not as good as that of water.

If your factory doesn’t have a ready-made cooling tower and you don’t want to build an additional system, an air-cooled chiller machine is a practical choice.

Water-Cooled Chiller

The advantage of this method is that water conducts heat well, and the unit efficiency is higher. A water-cooled chiller machine is more stable when operating at high load for a long time and can also save some electricity bills.

However, your factory must have cooling towers. If not, planning and rebuilding won’t be an easy task either

Scroll Type And Screw Type Choice

Scroll Chillers

For a cooling capacity of less than 30 tons, I sincerely recommend that you give priority to scroll compressors. It has a compact structure, operates quietly, and is easy to maintain on a daily basis.

However, it is necessary to note a reality: the maximum power of a single scroll machine is currently only around 40 horsepower. This means that if you need a slightly larger cooling capacity, say 35 tons, a single scroll machine might not be sufficient.

Of course, you can consider paralleling multiple scroll machines. For instance, if you need a cooling capacity of 50 tons, installing two 25-ton (or similar capacity) scroll machines in parallel can solve the problem. The advantage is its flexibility. But here is an important reminder: Never cram multiple scroll machines into the same refrigeration circuit. These can easily interfere with each other, affecting efficiency and even causing malfunctions. Separate circuits or independent control would be more secure.

Screw Chillers

When you clearly know that the cooling capacity demand is definitely over 30 tons or may expand significantly in the future, then the screw compressor needs to be seriously considered. Especially in large factories and data centers, its reliability and energy efficiency are often more cost-effective.

Evaporator Selection

For large projects exceeding 20 tons, I sincerely suggest that you give priority to the brazed plate direct expansion tube and shell evaporator. It is particularly suitable for large-scale systems where the refrigerant directly evaporates and absorbs heat. However, it is afraid of dirt and impurities, so you need to ensure the cleanliness of the water quality or medium in the factory first.

If your application conditions are more complex or you particularly value durability, then the shell and tube evaporator is definitely your good partner. Shell and tube heat exchangers can have very thick walls, and the materials can also be customized according to your requirements.

In this way, not only water, but even if you need to cool slightly corrosive liquids, or even relatively strong acid and alkali media, shell and tube heat exchangers can handle them.

FAQ

How to Maintain A Scroll Chiller?

Maintaining a scroll chiller is not difficult. Regularly check the circuit, keep a close eye on the refrigerant pressure with a pressure gauge, and repair it immediately if there is a leak. Don’t forget to replace the filter. If the compressor really breaks down, the scroll structure is precise. It’s troublesome to fix. In most cases, it’s more convenient for you to just replace it with a new one.

How to Maintain A Screw Chiller?

The maintenance of screw water chillers is a bit more challenging. Disassembly and assembly require skilled technicians. Although many parts can be replaced, the rotor and seals are very expensive, and the cost of replacing them once is not low. Do the math. If you don’t have a dedicated person to maintain it yourself, it will really cost a lot of money in the long run.

Customized Screw Chiller vs. Customized Scroll Chiller: Can Both Be Achieved?

Both can be customized. However, the international standardization degree of scroll chiller parts is relatively high. The customizable range is not wide. It’s quite convenient for you to customize in small batches for special scenarios. Screw-type water chillers have more comprehensive customizable capabilities.

Final Thoughts

The above is all the content of this article about the differences between the scroll chiller and screw chiller. Through the introduction of this article, we believe that you have gained a certain understanding of their features, uses, etc. There is already a rough judgment on how to choose between the two. If you still have any doubts, you can contact us for free at any time.

ChillerOne is a professional supplier of water chillers. We offer various types of water chillers. We look forward to becoming a good partner with you and achieving win-win cooperation together.