Different Types of Chillers in HVAC

Several types of chillers differ in their design, operation and benefits. Before choosing a chiller for your equipment, consider the following types:

For more information, please visit Huateng.

1. Water-Cooled Chillers

A water-cooled chiller pulls water into an evaporator through a primary return. The evaporator transfers heat from the water to a refrigerant, chilling the water before sending it through the primary supply to the system&#;s water tank. A water pump then distributes chilled water to climate-controlled spaces.

As the chilled water flows through each space and reaches the air handler, it absorbs ambient heat. The second law of thermodynamics, which states that heat naturally flows from higher-temperature regions to lower-temperature regions, makes this heat transfer possible.

If this is an air conditioning application, after the heat transfers to the chilled water, the air inside the air handler cools down. A fan forces the air through ductwork and into each space, cooling the equipment&#;s climate-controlled areas. When the warm water returns to the system&#;s chiller, it cools again and repeats the process.

In order for the refrigerant to absorb more heat from the water in each cycle, it must transfer the heat it absorbed during the previous cycle. The evaporator moves the heated, low-pressure refrigerant to a motor-operated compressor. The compressor increases the temperature and pressure before sending the refrigerant to the condenser.

Inside the shell & tube condenser, the water surrounding the refrigerant pipes absorbs heat from the refrigerant. The water inside the condenser is pumped to a cooling tower where it releases its absorbed heat. As the refrigerant continues through its cycle, an expansion valve (much like a water spray bottle nozzle) reduces the refrigerant&#;s temperature and pressure as it flows through on its way back to the evaporator where it restarts the process.

Water-cooled chillers provide the following benefits:

• Increased efficiency: Water transfers heat more effectively than air, so water-cooled chillers operate more efficiently than air-cooled chillers.
• Greater consistency: Water&#;s ability to transfer heat more effectively than air allows water-cooled chillers to operate more consistently.
• Longevity: Water-cooled chillers typically last longer than air-cooled systems.
• Requires water treatment: The Cooling Tower on a water cooled chiller system requires water treatment, filtration, and continuous water make-up.

2. Air-Cooled Chillers

An air-cooled chiller operates similarly to a water-cooled chiller. The only difference between and Air Cooled & Water Cooled chiller is in the condenser section of the units. And air cooled chiller utilizes an air-over condenser coil to remove heat from the refrigerant while the water cooled chiller uses a water to refrigerant condenser coil. The way each chiller removes heat from the process remains the same.

The refrigerant then increases its temperature and pressure by moving through the compressor until it reaches the condenser where outside air circulates from a fan. The condenser absorbs the refrigerant&#;s heat and expels it into the surrounding air. Finally, the refrigerant returns to the evaporator through the expansion valve to begin the process again.

Air-cooled chillers offer the following benefits:

• Low maintenance costs: Air-cooled chillers typically have low maintenance costs.
• More compact: Because air-cooled chillers lack the water tower and pump that water-cooled chillers contain, they take up less space.

3. Scroll Chillers

A scroll chiller compresses refrigerant using a scroll compressor. It contains a stationary scroll plate and an orbiting scroll plate, which rotates around the stationary component and compresses the refrigerant to raise its temperature and pressure (Link: https://youtu.be/yNgqI4XPUZc). This process prepares the refrigerant for the rest of the cooling process.

Scroll chillers have the following benefits:

• Smooth operation: Scroll compressors contain fewer moving parts and produce less torque variation, allowing scroll chillers to operate more quietly and smoothly than other chillers.
• Efficiency: Scroll chillers can output more cooling per energy unit than other chiller systems, making them a highly efficient option.
• VFD options: Newer models offer scroll compressors with a built-in variable frequency drive for variable speed control.

It&#;s best to avoid choosing a tandem scroll compressor chiller unit. It&#;s much better to choose a scroll compressor that applies a single compressor to each refrigeration circuit &#; this eliminates the risk of burnouts damaging multiple compressors.

You can choose between industrial air-cooled scroll chillers, air-cooled portable scroll chillers and water-cooled portable scroll chillers for your applications.

4. Screw Chillers

When it comes to a scroll vs. a screw compressor, it&#;s important to note that screw compressors handle larger capacities than scroll compressors. While scroll chiller tonnages vary between 2 and 140 tons (60HP maximum single compressor size), screw chillers vary between 30 and 400 or more tons. The main difference between screw and scroll chillers is that screw chillers use one or two rotating screws to apply force and compress refrigerant. Screw compressors are most commonly found in industrial process and petrochemical applications.

5. Explosion-Proof Chillers

Some industrial machinery is susceptible to explosions, requiring industrial explosion-proof chillers to maintain safety. Explosion-proof chillers are manufactured with a reinforced, specialized design and contain features that protect their components from flammable materials. This design prevents potential explosions to protect employees, equipment and facilities.

Few air-cooled chiller manufacturers have the expertise to provide reliable explosion-proof chillers. If your equipment operates in hazardous conditions, it&#;s crucial to select an explosion-proof chiller from a reputable manufacturer that follows National Fire Protection Agency standards and codes.

6. Low-Temperature Chillers

Some industrial operating conditions require the leaving fluid temperature to remain below 35 degrees Fahrenheit. Low-temperature chillers ensure equipment operates efficiently for applications such as petrochemical processes and ice rink cooling that require low leaving fluid temperatures. Some units can run down to as low as -40 degrees F leaving fluid temperature. At these conditions, special heat transfer fluid is required.

7. Glycol Chillers

An industrial glycol chiller features a reliable digital temperature controller. This controller makes it possible to maintain ideal temperatures for food and drink products. Wineries and breweries often use glycol chillers for this reason.

Water Chillers are the most common type of units used for cooling large commercial spaces. Each chiller has its own set of pros and cons. Here, we have listed 5 types of water chillers advantages and disadvantages based on facility budget, available energy sources and the application.

1. The Screw Water Chillers

Screw water chillers are the units that use various types of screw compressors as their mainframes. The utility model is an assembled refrigeration device composed of a screw compressor, a condenser, an evaporator, a thermal expansion valve, an oil separator, an automatic control element and an instrument, etc. At present, Screw water chillers are more and more widely used in the field of refrigeration and air conditioning all over the world. The typical refrigerating capacity ranges from 700KW to KW.

Advantages:

1. Simple structure, few parts, few wearing parts, and long life.
2. It is a stable, low load operation without &#;surge&#; phenomenon.
3. The compression ratio and EER value are high.
4. Stepless regulation in the range of 10%~100%, high efficiency under partial load and power saving.

5. Insensitive to wet stroke.

Disadvantages:

1. The price is higher than the piston water chiller. Single capacity than centrifugal water chiller small, low speed than centrifugal water chiller also.
2. The lubricating oil system is complex and consumes a lot of oil.
3. large capacity unit noise than centrifugal water chiller high.
4. High machining and assembly accuracy are required.

2. The Piston Water Chiller

The Piston chillers are chillers whose main engine is a piston compressor. The unit is composed of a compressor, condenser, evaporator, and thermal expansion valve, and equipped with automatic energy regulation and automatic safety protection device. The piston compressor system is relatively simple, this kind of compressor in general low-temperature working conditions with more!

Advantages:

If you want to learn more, please visit our website Types of Industrial Chillers.

1. Wide applicable pressure range. Strong maintenance.
2. Multi-compressors, high-speed multi-cylinder, performance can be improved.
3. Simple materials, general metal materials available, easy processing with low cost.

Disadvantages:

1. Too many parts, accessories are much more easily damaged.
2. Low compression ratio, small cooling capacity with a single unit, cylinder unloading adjustment. No stepless     regulation.
3. The Piston water chillers working up and down reciprocating.
4. Sensitive to liquid shock.

3. The Modular Water Chiller

It is composed of multiple modular chiller units in parallel. Coordinated control by microcomputer circuit work more, can independently adjust energy each compressor, modular units can be made up by as many as 13 units, modular chiller with computer monitoring and control system, control of the whole unit, according to the size of the air conditioning load, regular start-stop the compressor or will high speed to low speed running, including each independent refrigeration system and the machine running.

Advantages:

1. Adjust the number of modules in operation at any time according to the change of cooling load, so as to achieve the best matching between output cooling capacity and air-conditioning load and save energy consumption.

2. Multiple compressors are guaranteed to work in parallel.

3. Lightweight, small size, saving the building area;

4. The modular combination, providing maximum spare capacity for the refrigeration system, and expanding unit capacity is very simple and feasible

Disadvantages:

1. High requirements for water quality. Once scaling and blocking, it will affect the heat transfer of the condenser and evaporator.
2. The cost is high, many parts, vulnerable parts, high maintenance costs.
3. Low compression ratio and small single cooling capacity.
4. Poor adjustment performance under a partial load of a single head, no stepless adjustment
5. Large weight index of unit refrigerating capacity.

4. The Centrifugal Water Chiller

The centrifugal water chiller is cooled by freon refrigerant evaporating in the evaporator to absorb the heat of refrigerant water. The freon wet steam after evaporating is compressed into high-temperature and high-pressure gas by the compressor, which condenses in the water-cooled condenser and turns into liquid, and enters the evaporator for recycling through expansion valve throttle.
Thus making 7 &#; &#; 12 &#; air terminal air conditioning chilled water supply.

Advantages:

1. High rotating speed of impeller, large gas transmission capacity and large single machine capacity
2. Less vulnerable parts, reliable work, compact structure, smooth operation, small vibration, low noise
3. Small weight index of unit refrigerating capacity
4. The refrigerant is not mixed with lubricating oil, evaporator, and condenser of good heat transfer performance
5. EER value is high, which can be adjusted continuously within 10%~100%.

Disadvantages:

1. The single-stage compressor will appear &#;surge&#; phenomenon at low load and run smoothly at full load
2. Strict requirements on material strength, machining accuracy, and manufacturing quality
3. When the operating condition deviates from the design condition, the efficiency drops rapidly, and the cooling capacity decreases faster with the decrease of evaporation temperature than the piston type.
4. Centrifugal negative pressure system, external gas easy to invade, there is a risk of chemical changes corrosion pipeline

5. The Water source heat pump unit

A heat pump type integral water-air or water-water air conditioning unit that uses water as the heat source for cooling or heating cycle, and use water as the heat source for heating and water as the exhaust heat source for cooling.
The cold (hot) source is water that circulates in common pipes, water that is extracted from Wells, lakes or rivers, or water that circulates in underground coils to produce cold (hot) wind or cold (hot) water.
The utility model includes a side heat exchanger, a compressor and a heat source side heat exchanger with cooling or a cooling and heating function.

Advantages:

1. Energy saving and heat recovery during winter operation.
2. One unit with multiple operations, stable operation.
3. Significant environmental effects.
4. High energy efficiency ratio.

Disadvantages:

1. Restricted by the available water source conditions and the geographical structure of the water layer.
2. The system is prone to water bunching on the source side and the load side.
3. Affected by energy policies and fuel prices of different regions and countries.
4. The one-time investment and operation fee are relatively high.

If you are looking for more details, kindly visit How Does a Water Cooled Chiller Work.