What is a chiller? Structure and operating principle of the chiller system

What is a chiller?This is a central chilled water production system, playing a key role in providing a source of cold water for heat transfer or cooling equipment in industrial production lines. Currently, water chiller It is a standard technical solution in pharmaceutical, electronics, and food factories to ensure precise operating temperature maintenance. Based on over 20 years of design and construction experience. cold storage and industrial refrigeration systems, Tan Long We will provide a detailed analysis of the structure, operating principles, and key technical specifications to help businesses choose the most suitable chiller system.

Learn about what is Chiller?

What is a chiller?Technically speaking, a chiller is a central chilled water production system that uses a thermodynamic cycle to cool a liquid (usually water or a glycol mixture). This chilled water is then transported through a piping system to heat exchangers to lower the temperature of the space or industrial production processes.

Unlike residential air conditioning systems, water chiller It operates on the principle of absorbing heat from the environment to be cooled and releasing that heat to the outside through an air condenser or water condenser.

Applications of Chiller systems in commercial and residential settings.

In the HVAC (Heating, Ventilation, and Air Conditioning) field, chiller systems are the optimal solution for large-scale projects such as high-rise buildings, shopping malls, or hospitals. They are an effective alternative to split-system or VRV/VRF cooling systems due to their capabilities:

• Handles extremely high-capacity refrigeration loads with high durability.
• Easily connect to terminal devices such as AHUs or FCUs to regulate clean air.
• It operates reliably in demanding environments where conventional systems cannot meet the required specifications.

The role of chillers in industrial production.

In industry, chillers play a crucial role in maintaining standard operating temperatures for machinery and fluid flows in production lines. Precise temperature control using industrial chillers is key in many fields:

• Plastics industry: Cooling the molds in injection molding machines increases productivity and product surface quality.
• Food industry: In conjunction with the system cold storage For rapid product cooling, petroleum preservation, and seafood processing.
• Electronics & Healthcare Industry: Maintain a cleanroom environment and cool diagnostic imaging and metal plating equipment.

Understanding What is a chiller? Choosing the right type of equipment will help businesses optimize operating costs and ensure the safety of the entire technical system.

Detailed structure of an industrial chiller system.

Understanding What is a chiller? It's not just about the concept, but also about how the mechanical and electronic components work together. A cluster water chiller The standard comprises seven main components, each playing a crucial role in the refrigeration cycle.

Compressor

The compressor is the most important component, playing a crucial role in creating the pressure difference to circulate the refrigerant throughout the entire system. Currently, Tan Long offers a wide variety of models. refrigeration compressor Suitable for various power requirements:

• Screw compressor: Suitable for large refrigeration loads and reliable operation.
• Scroll compressors: Priority is given to small and medium-sized power systems that operate quietly.
• Piston and centrifugal compressors: Options available for specific technical requirements.

Technical notes: Due to the high pressure involved, compressors typically generate considerable noise during operation, requiring soundproofing solutions or hearing protection during routine inspections.

Condenser

The condenser's function is to cool the refrigerant after it leaves the compressor. Depending on the cooling requirements... What is a chiller?We have two types of condensers:

• Water-cooled condenser: Water from the cooling tower circulates in the copper pipes to absorb heat from the refrigerant (which runs outside the pipes).
• Air-cooled condenser: A forced-air fan blows air across the aluminum fins to dissipate heat directly into the atmosphere.

Expansion Valve

Located between the condenser and evaporator, the expansion valve's function is to abruptly reduce the pressure and temperature of the refrigerant. This expansion process allows the refrigerant to transition to a state where it is ready to absorb heat at the evaporator, optimizing the cooling efficiency of the entire system.

Evaporator

This is the main heat exchanger between the refrigerant and the water (or liquid to be cooled). industrial refrigeration In this process, the refrigerant will boil and absorb heat from the flowing water, turning the water into "cold water" (usually 7°C) to supply the air conditioning system or production line.

Power Unit

The power supply unit is responsible for providing and distributing the current to the entire machine assembly. The system includes circuit breakers (Aptomat), starters (Star-Delta or Soft Start), and overcurrent and phase imbalance protection devices to ensure absolute safety for the equipment.

Controller

The control system acts as the "brain" monitoring all operating parameters such as pressure, temperature, and current. At Tan Long, we prioritize integration. PLC control cabinet modern, allowing:

• Automatically adjusts power output according to actual load.
• Timely error warnings help prevent serious malfunctions.
• Synchronized connection with the building management system. BMS For remote monitoring via the internet.

Water Box

Water tanks are installed at both ends of the evaporator and condenser (for water-cooled systems). The design of the water tanks helps to distribute and guide the water flow through the copper pipes most efficiently, minimizing resistance and increasing the heat exchange area.

What are the components of a chiller system? Classification and detailed structure.

After understanding the concept What is a chiller?Understanding the components is crucial for businesses to operate a stable and energy-efficient system. A central cooling system is not simply a standalone machine, but a technical network combining chilled water production equipment, transfer pumps, and terminal devices.

Currently, based on the condenser cooling method, Tan Long divides the most common systems into two types:

Water-Cooled Chiller System

This is the most efficient cooling solution, commonly used in large-scale manufacturing plants or in combination with other systems. cold storage industrial applications to optimize cooling load.

The core components include:

• Water Chiller Unit: The central unit performs a vapor compression cycle to cool the water.
• Cooling Tower: It plays a role in releasing heat from condensed water into the surrounding environment.
• Chilled Water Pump: Its function is to circulate chilled water from the chiller to the consumption points.
• Condenser Water Pump: Hot water is transferred from the condenser to the cooling tower for cooling.
• Piping, valves and fittings: It is designed with technical insulation to prevent heat loss.
• End heat exchanger (FCU/AHU/PAU): These devices directly cool the air in a space or production line.

Air-Cooled Chiller System

Unlike water-cooled systems, water chiller Air-cooled systems use forced-air fans to exchange heat directly with the air. This system has the advantage of a compact design, does not require a cooling tower, and does not need a continuous water supply.

The main components of the system include:

• Air Cooled Chiller Unit: It comes with an integrated copper tube condenser with aluminum fins and a cooling fan system.
• Chilled Water Pump: Push cold water through the heat transfer system.
• Water piping system: Direct the central cold water supply to the areas where it is needed.
• Terminal devices (AHU/FCU/PAU): It performs the air cooling function using cold water from the chiller.

Detailed analysis What is a chiller? Understanding the characteristics of each system type will help Tan Long engineers advise customers on the most optimal design solution in terms of installation area and long-term investment costs.

Chiller system operating principles: Detailed operating procedure

To grasp the essence What is a chiller?Engineers and investors need to clearly understand the heat exchange process between the refrigerant, water, and the environment. Basically, the system operates based on the state change of the refrigerant to absorb heat from the water (cooling the water) and release that heat to the outside.

Depending on the cooling method, the operating process of water chiller It will have its own unique characteristics:

Operating principle of water-cooled chillers.

This system operates through two separate but closely interacting water circulation loops at the central chiller unit:

• Chilled Water Circuit: In the evaporator, the refrigerant absorbs heat from the water, lowering its temperature to the standard level. 7°CThis chilled water is pumped by a chilled water pump to end-user heat exchangers such as FCU/AHU units to cool the air-conditioned space or production machinery. After absorbing heat from the load, the water level rises by approximately... 12°C and then circulate back to the evaporator to start a new cycle.
• Cooling Water Circuit: In the condenser, the high-temperature refrigerant transfers heat to the cooling water, causing the water temperature to rise by approximately... 37°CThe condenser water pump will push this hot water up to the cooling tower to release heat into the air, lowering the water temperature. 32°C before returning it to the condenser.

Technical notes: The temperature difference (Delta T) between the inlet and outlet water can be flexibly customized by Tan Long's engineering team based on the specific requirements of each construction project. cold storage or a specialized production line.

Operating principle of air-cooled chillers.

This system has a simpler design because it eliminates the cooling water circulation loop and cooling tower, instead relying on direct heat exchange with the air.

• Water cooling process: Similar to water-cooled systems, the water is cooled down in the evaporator. 7°C To supply power to the FCU/AHU units. After performing its cooling task and receiving the increased temperature. 12°CThe water returns to the chiller to be reprocessed into chilled water.
• System cooling process: Instead of using water, the refrigerant, after absorbing heat from the evaporator, is passed through a copper tube-aluminum fin heat exchanger. Here, high-powered forced-air fans blow air directly through the coil to cool the refrigerant before it returns to the vapor compression cycle.

Detailed analysis What is a chiller? From a principled perspective, this helps businesses determine the desired performance (COP/EER), thereby making an informed decision about whether to invest in an air-cooled system (prioritizing compact space) or a water-cooled system (prioritizing high efficiency for large capacities).

Advantages and disadvantages of chiller systems compared to other air conditioning solutions.

The evaluation of advantages and disadvantages is based on a thorough understanding. What is a chiller? This will help businesses make the right investment decisions. Compared to split air conditioning systems or VRV/VRF systems, central chiller cooling systems offer superior advantages in terms of capacity and technical customization capabilities.

The outstanding advantages of the Chiller system

Here are the reasons why. water chiller It is a top priority for large-scale industrial and commercial projects:

• Extremely wide power range: The system is capable of handling cooling loads up to 3000 TonsSuitable for complexes, electronic component manufacturing plants, or systems. cold storage large scale.
• Ensuring the aesthetic appeal of the building: The central chiller unit can be neatly installed in the basement machine room or on the rooftop, without affecting the overall architecture.
• Capability to transmit cold water over long distances: Using water as a refrigerant in combination with a distribution pump system, chillers effectively solve the problem of system resistance, allowing chilled water to be delivered to high-rise buildings or production facilities far from the center of the unit.
• High energy efficiency: Index COP (Coefficient of Performance) The chiller's power is very high. When combined with PLC control cabinet And with inverters for pumps/fans, the system helps optimize operating electricity costs.
• High applicability and customizability:
  • The waste heat from the condenser can be used to heat hot water for hotels and hospitals.
  • The flexible design with primary/secondary pump circuitry allows for precise water flow regulation in each area.
• Intelligent operation: Easily integrated into building management systems. BMSThis allows for centralized monitoring and control of all technical parameters.
• Saving on material costs: Stable working water temperature with high inlet/outlet differential (up to 9.5°CThis helps to significantly reduce the size of water pipes, thereby lowering initial installation costs.
• Equipment durability and lifespan: The system is designed to stringent industry standards, resulting in a much longer operating lifespan compared to residential air conditioners.

Limitations to consider when investing in chillers.

Besides the advantages, when researching... What is a chiller?The investor also needs to consider the following factors to have a contingency plan:

• Initial investment costs: The total cost for compressors, cooling towers, pumps, and piping is typically higher than for split-system air conditioning.
• Complex installation required: The construction process requires close coordination between mechanical, electrical, and plumbing (MEP) components, demanding high technical expertise in insulation cladding and control system connections.
• Professional operations team: Due to their complex technical nature, the operation and maintenance of chiller systems require highly skilled engineers to ensure efficiency and safety.

In Tan LongWe not only provide equipment but also offer comprehensive solutions, helping businesses maximize the advantages and overcome the limitations of chiller systems based on the specific conditions of each project.

4 Common Chiller Water Circuit Diagrams in Refrigeration System Design

After being identified What is a chiller? After selecting the appropriate machine, the next equally important step is designing the water circuit diagram. Choosing the right water circuit diagram will determine the heat exchange efficiency, equipment durability, and the company's monthly electricity costs.

Below are the four most common water circuit diagrams applied by Tan Long engineers in real-world projects:

A group of water channels with constant flow.

This is a traditional solution commonly used in systems with fixed or minimally fluctuating cooling load requirements. This circuit utilizes a constant flow pump, suitable for manufacturing plants with continuously operating production lines.

• Chiller system with water circuit 1 and 2-way valve: In this diagram, terminal devices such as FCU/AHU use 2-way valves to open/close the water supply. To ensure stable system pressure, a bypass line combined with a continuously variable solenoid valve (Modulating Valve) is installed on the main pipeline to regulate the amount of excess water returning to the return line.
• Water circuit chiller system 2 with 3-way valve: Instead of using a central bypass line, each FCU unit will be equipped with a 3-way valve. When the cooling load decreases, the valve will redirect chilled water directly through the local bypass line to return to the chiller without passing through the evaporator, helping to maintain a stable water flow through the evaporator.

A group of water channels with flow rates that vary according to actual load.

In today's energy optimization trend, variable flow water circuits are a top choice for commercial projects, office buildings, or other energy-efficient systems. cold storage Intelligent. The biggest advantage of this circuit is its superior power saving capability when the system is running in part-load mode.

In the Vietnamese market, based on climatic conditions and operational characteristics, the following two types of diagrams are preferred:

• Water-based Chiller System 3 – Variable Primary Flow (VPF): This is the primary variable flow circuit. The system uses only a single pump unit controlled by a frequency converter. PLC control cabinetA small bypass valve assembly is installed to maintain a minimum water flow rate to protect the evaporator from freezing at extremely low loads.
• Water-flow chiller system 4 – Primary/Secondary Flow: This is a separate circuit between the primary and secondary pumps.
  • Primary pump: Maintain a stable water flow through the cluster. water chiller.
  • Secondary pump: Variable flow rates are used to adjust the flow rate according to the actual needs of the FCU/AHU units.
  • These two circuits are connected via a decoupler pipe to eliminate the pressure difference between the two circulation loops.

Understanding the principles of these diagrams, in addition to knowledge, is essential. What is a chiller? This helps engineers develop solutions for separating series or parallel circuits for high-rise projects or large-scale complexes.

Tan Long advises investors to prioritize variable frequency drive (VPF) or primary/secondary circuits to minimize energy waste, and to integrate an automatic monitoring system to accurately control temperature differences at the inlet/outlet.

Classification of common chiller systems currently available.

Classification What is a chiller? Accurate selection will help operations managers and investors choose the right equipment configuration for the project. Based on the heat exchange method of the condenser and its structural characteristics, water chiller They are divided into the following main groups:

Classification according to condenser cooling method

This is the most common classification in the industrial refrigeration industry, directly affecting performance and installation space:

• Water-cooled chiller: This is a system that uses water as a cooling medium for the condenser. This type has the advantages of extremely high cooling capacity, stable performance, and high durability, making it particularly suitable for industrial areas, pharmaceutical factories, or other similar systems. cold storage large scale.
• Air-cooled chiller: Instead of using water, the system uses fans to blow air directly through the condenser coil. This type is suitable for small to medium-sized projects, areas with limited space for cooling towers, or areas with water sources contaminated with alum or salt.

Other technical classification criteria

Beyond cooling methods, when delving deeper into the technical aspects... What is a chiller?We can also classify devices based on the following factors:

1. According to compressor type: This component determines the operating capacity. Depending on the needs, the system will use it. refrigeration compressor Screw, Scroll, Centrifugal, or Piston type.
2. According to the heat recovery function: Modern chillers are capable of recovering excess heat from the cooling process to heat hot water, helping to save energy for buildings or factories.
3. According to the water flow rate through the evaporator:
   • Constant Flow: Suitable for stable cooling loads.
   • Variable Flow: Inverters are often integrated to optimize power output based on actual load.
4. Absorption Chiller: This type of cooling system does not use a mechanical compressor but instead employs a heat absorption cycle (typically using thermal energy from steam or hot water) to produce cooling, helping to reduce electricity costs in areas with readily available excess heat.

Each classification option What is a chiller? Each type of engineering has its own unique technical characteristics. Based on your actual needs, budget, and environmental conditions, our team of engineers will advise you on the most optimal solution.

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How to calculate capacity to install a cooling chiller

Normally, factories use two methods to calculate the installed capacity of water chillers as follows:

Calculated based on available parameters

In the Chiller's manual (catalogue), the following parameters are usually provided:

• Required cooling capacity of the machine: Qll (kW cooling)
• Cold water flow: m³/h, liter/min
• Cold water temperature to be maintained: ℃ and °F

The formula for calculating cooling capacity is:
Q = 4.186 * At * Qll / 3.6 (kW cooling)

In there:

• At is the temperature difference between the plastic in its molten state and after it has been cooled.

When converting from a cooling tower system to a Chiller, the capacity can be calculated as follows:

For example:
If the cooling tower has a capacity of 20 Tons, with the inlet water temperature of 30℃ and the outlet water temperature of 35℃, then to reduce 5℃, 20 Tons of cold is needed. To lower the water temperature from 20℃ to 25℃, the Chiller system needs a capacity of 40 Tons of cold.

Calculated by cooling capacity for the machine

To calculate the cooling capacity of the machine, we use the following formula:

Q = Cp * At * M / 3600 (kW cooling)

In there:

• At: The temperature difference between the plastic when it is still molten and after it has been cooled. Typically, At is taken as 200°C (with an ideal difference of 230°C to 30°C).
• Cp: Specific heat of plastic.
• M: Product yield in one hour (unit: Kg).

Some notes when calculating Chiller capacity:

• Calculate surplus capacity: Because over time, the machine will gradually lose performance, it is necessary to calculate surplus capacity to ensure that the machine can still operate effectively.
• Backup machine: Backup machines are needed to ensure continuous production, even if the main machine fails. Backup machines also help coordinate operations between machines, allowing them to rest, thereby increasing the life of the machine and electrical system.

What are the criteria to help you choose to buy a Chiller?

Below are the criteria and experiences to help you choose the right Chiller:

Find a reputable supplier

Choosing a reputable supplier brings many benefits, the most prominent of which is professional and dedicated advice from a team of staff with solid expertise. This makes it easy for you to choose a Chiller system that is suitable for your production process and factory operating requirements. In addition, reputable suppliers regularly check and maintain the Chiller system periodically, ensuring stable performance and prolonging the life of the equipment.

Determine operating capacity

To meet production requirements, the minimum capacity of the Chiller is usually from 100HP or more. However, depending on the nature and scale of each factory, some small production facilities can choose air-cooled Chiller lines with a capacity of about 30HP, which is more suitable for their operating needs.

Compare prices

The price of a Chiller will vary depending on the supplier and different product lines. In the current market, the price of a Chiller cooling system usually ranges from 20 to 30 million VND.

Because of the variety of prices from different suppliers, businesses need to be cautious and consider carefully before deciding to buy. This is a large-sized device, with a high investment cost and a long-term usage time.

Above are detailed answers to the question. What is a chiller? but Tan Long want to share with you. Hope you will have more information to buy the right Chiller machine. If you still have questions about this type of machine, you can call us for answers.

Contact information:

• Head office: 86 Dong Den Street, Ward 14, Tan Binh District, Ho Chi Minh City, Vietnam
• Monday – Saturday: 8:00am-5:30pm
• Hotline: 028 38494943 – 028 62937108