Aug. 25, 2025
When a damaged chiller claim lands on your desk, you need to be ready for the complexities that come with it. These systems are often intricate and specialized based on the space or equipment they’re cooling, meaning they present their own challenges to insurance adjusters like you. If you’re not familiar with this complicated cooling equipment and you’re working on a claim that includes one, you’ll want to know the basics.
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Water pipes for a chiller system
How Do Chillers Work?
Chillers transfer heat away from a space that requires climate control much like a traditional split system or package unit does, but they use water (or a water solution) to do so instead of air. There are two types of chillers: water-cooled and air-cooled. They work similarly throughout most of the process until the refrigerant reaches the condenser, and both are outlined in the following sections.
Water-Cooled Chillers
Diagram A
The cooling process begins when water enters the evaporator from the primary return where heat is transferred from the water to the refrigerant.
The now-chilled water is then sent to the water tank via the primary supply (shown in blue), where it is distributed to the various climate-controlled spaces by the water pump. Because heat always moves from hot to cold as stated by the second law of thermodynamics, the chilled water absorbs the conditioned space’s ambient heat in the air handler. A fan then forces the cooled air into the space via the ductwork. The warmer water is then returned to the chiller to be cooled once again.
In the meantime, the heat absorbed by the refrigerant (path shown in green) in the evaporator needs to be transferred to allow the refrigerant to absorb more heat. The low-pressure, high-temperature refrigerant moves from the evaporator to the motor-run compressor, which increases the pressure and temperature.
After that, the refrigerant enters the condenser. Water-cooled chillers use water to surround the refrigerant pipes and draw in the heat (path shown in red). The water is then pumped into a cooling tower to release the heat. After condensing, the refrigerant goes through an expansion valve to reduce pressure (and temperature) before returning to the evaporator, where the process begins again.
Air-Cooled Chillers
Diagram B
Like with water-cooled chillers, the process begins with the primary return bringing warm water to the chiller. Heat is transferred in the evaporator to the refrigerant, and the water runs through the primary supply to the cooled space. The refrigerant moves through the compressor to raise the pressure and temperature, and then it reaches the condenser. Here, fans circulate outside air through the condenser, which absorbs heat from the refrigerant (again, the second law of thermodynamics dictates that hot moves to cold) before expelling this heat to the ambient air. The refrigerant then goes through the expansion valve (as before) and returns to the evaporator.
Where Are Chillers Used?
Chillers have several uses and are sometimes preferred over traditional split systems or package units because the water conducts heat better than air. This is also why water-cooled chillers are known for being more consistent and efficient in their performance and for having a longer lifespan than their air-cooled counterparts. Water-cooled chillers are common in medium and larger facilities (so long as they have an adequate water supply), such as airports, hospitals, hotels, shopping malls, commercial buildings, and more. (Pictured: A portable chiller)
Air-cooled chillers are more prevalent in small to medium sized facilities where space and water may be limited. The costs to install and maintain these chillers are lower than that of their water-cooled counterparts, but they typically have a shorter lifespan. These chillers are commonly used for restaurants, corporate and sporting events, and temporary structures.
Chillers are also often used for industrial or medical applications. Assembly equipment, construction sites, lasers, MRI machines, and various other high-powered equipment and facilities may require chillers to maintain a workable temperature.
Common Problems That Affect Chillers
Corrosion
Chillers use metal tubes (usually made of copper or carbon steel) to transfer water between the chiller and the climate-controlled space. The simple presence of oxygen in water can cause corrosion, but if the water and pipes are treated properly, this can significantly reduce the risk. However, if the water treatment is inadequate, sediment, minerals, and bacteria can enter the system. If there is a buildup of sediment or bacteria that causes oxygenation levels to differentiate, the metals can begin to corrode. In addition, any point where two different metals are used can be at risk for corrosion due to their different electrochemical properties. No matter how the corrosion occurs, it can cause leaks that will damage the chiller, reduce its efficiency, and possibly damage the area surrounding the chiller.
Compressor for a chiller
Poor Maintenance
These complex machines require a lot of maintenance to keep them in good working order. If proper steps aren’t taken, the chiller can corrode, clog, lose efficiency, or experience a number of other issues. For example, if proper water treatment isn’t maintained or if open cooling towers aren’t cleaned, sediment or particulates can be introduced to the system, causing clogged pipes and poor heat transfer. An air-cooled chiller’s condenser can be blocked by debris or become caked in dirt, which also lowers efficiency.
Electrical Issues
The electrical systems within a chiller are carefully designed and as complex as the rest of the machine. They can easily be thrown off balance by a high voltage surge or wear and tear. If there is a grounding issue or a power supply failure, the chiller may detect this and shut itself off. Overloading the chiller can cause it to overheat, which will likely result in failure. Wires and cables can become loose or damaged after maintenance or due to negligence, which can result in chiller malfunctions.
Further reading:For more Water Cooled Chiller Systeminformation, please contact us. We will provide professional answers.
We Can Help Settle Your Chiller Claims
Chiller claims are no walk in the park – several components can malfunction and cause the entire system to fail, and the source may not always be clear. To handle them properly, you may need an expert opinion. If you’re handling a chiller claim, let us help! Our trained technicians will document the damages and our experts will put together a comprehensive report outlining damages, cause of loss, and costs involved with repair or replacement.
Water cooled chiller design data. In this article we are going to be taking a very detailed look at the design data for a centrifugal, water cooled, chiller. This is a pretty advanced chiller video, so if you’re new to the topic then I highly recommend you start from the basics first.
Scroll to the bottom to watch the YouTube tutorial video on chiller design data.
I want to stress that this is simply design data. Every chiller is different and you should speak to your manufacturer for the relevant information. The results will vary from the real world and also with loading.
In the illustration above we have shown the main chiller components. The compressor, which is the driving force of the refrigerant around the system. The condenser which removes the unwanted heat from the system and send this to the cooling tower. The expansion valve which expands the refrigerant and controls the superheat into the compressor and the evaporator which collects the unwanted heat coming from the building and generates the chilled water.
We’re going to be looking at all the points on these two charts to see the pressure, temperature, enthalpy and entropy are around this system. The left chart is our Temperature v’s Entropy chart and the right chart is our Pressure v’s Enthalpy chart.
In this example the compressor is pushing a refrigerant with a flow rate of 16.5 kg/s (36.4 lbm/s). That motor is then consuming 425.9 kilowatts and the compressor is running 100% load. If the chiller runs at part load then the values will be different.
The refrigerant is being sucked in from the evaporator (Point 1) at around 356 kPa (3.56 Bar) and at a temperature of 5.5 ° C (41.9 ° F). The refrigerant enthalpy is 402 kJ/kg (173 BTUs/lbm). The entropy will be 1.73 kJ/kg.K (0.41 BTUs/lbm.F).
The compressor is compacting the refrigerant into a smaller space, and looking at our charts we know that the enthalpy is going to increase, the entropy is going to slightly increase and the pressure and temperature will massively increase.
When the refrigerant leaves (Point 2), it will be 915 kPa (9.15 bar). The temperature reaches 43.6 ° C (110.5 ° F). The enthalpy is now 426 kJ/kg.K (183 Btu/lbm) and the entropy is now 1.74 kJ/kg.K (0.042 Btu/lbm.F).
Remember the temperature of the refrigerant entering into the condenser has to be higher than the incoming condenser water temperature for heat transfer to occur. If they were the same temperature, then no heat transfer would occur and the chiller would do no cooling.
The next part we’ll look at is the condenser. In this example the condenser water is flowing through the condenser at 116.6 L/s (247 cfm). The condenser water is coming into the condenser, from the cooling tower, at 29 ° C (84.2 ° F). The refrigerant will then transfer the buildings unwanted heat into the condenser water. This will increase the temperature of the condenser water, so when it leaves to go back to the cooling tower it will be around 35 ° C (95 ° F).
Now the reason the flow rate is higher in the condenser compares to the evaporator is because the condenser has to reject more heat. It also has to take the heat away from the compressor and other parts of the machine.
The refrigerant came from the compressor and entered the condenser at a pressure of 915 kPa (9.15 Bar), a temperature of 43.6 ° C (110.5 ° F) with an enthalpy of 426 kJ/kg.K (183 Btu/lbm) and an entropy of 1.74 kJ/kg.K (0.428 Btu/lbm.F).
Once the refrigerant has give away some of its energy to the circulating condenser water, it will now leave as a liquid at 36.1 ° C (97 ° F) but still at the same pressure as it entered. It’s entropy will have dropped to 1.17 kJ.kg.K (0.28 BTU/lbm.F) and the enthalpy increases to 250 kJ/kg.K (107.5 BTU/lbm). It then enters into the expansion valve.
The expansion valve controls the flow of refrigerant, it measures the superheat on the suction line of the chiller and then reacts to this by allowing or restricting refrigerant flow to maintain a certain value. The refrigerant is entering the expansion valve as a liquid and leaving as a vapour/liquid mixture.
It enters, in this example, at a temperature of 36.1 ° C (97 ° F), a pressure of 915 kPa (9.15 Bar), the entropy is 1.17 kJ.kg.K (0.28 BTU/lbm.F) and the enthalpy is 250 kJ/kg.K (107.5 BTU/lbm).
The refrigerant is expanded through a small orifice which sprays the refrigerant. It expands into a larger volume and decreases in pressure as a result, which allows it to drop in temperature as it’s now not packed so tightly. It will leave at a temperature of 5.5 ° C (41.9 ° F), a pressure of 356 kPa (3.56 Bar) and from the charts we know it will maintain the same enthalpy but the entropy will change slightly and it leaves at 1.20 kJ/kg.K (0.29 BTU/lbm.F).
The evaporator generates the cold “chilled water” which cycles around the building, providing air conditioning and collecting the buildings unwanted heat. This now warm chilled water returns to the evaporator and transfers this heat into the refrigerant, the chilled water then leaves cooler and cycles around the building, meanwhile the refrigerant boils and carry’s the thermal energy to the compressor.
In this example, the chilled water is flowing through the evaporator at around 99.5 Litres per second, which is around 210 cubic feet per minute. The chilled water enters the evaporator at around 12 ° C (53.6 ° F). After the chilled water has transferred it’s heat over to the refrigerant, it will leave the evaporator at around 6°C (42.8°F).
The refrigerant is picking up thermal energy but the temperature only changes slightly which confuses many people. The reason it doesn’t increase dramatically is because it is undergoing a phase change from a liquid to a vapour so the thermal energy is being used to break the bonds between the molecules. The enthalpy and entropy will increase and this is where the energy is going
When the refrigerant leaves it will be a slightly superheated vapour at 5.5 ° C (41.9 ° F), a pressure of 356 kPa (3.56 Bar) an entropy of 402 kJ/kg.K (173 Btu/lbm) and an enthalpy of 1.73 kJ/kg.K (0.41 btu/lbm.F).
The refrigerant then returns to the compressor to start the cycle all over again.
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