Chiller systems are vital for temperature control and cooling in a number of industries. Choosing the right type of industrial chiller for process and space cooling can reduce cooling costs, minimise downtime and increase operational efficiency.
This article will describe the different types of chillers available for commercial and industrial applications and the benefits of each. The aim is to help you make an informed purchasing decision.
The three main types of industrial chillers in use today are air-cooled chillers, water-cooled chillers and evaporative condensing chillers. Let us take a closer look at these three.
The most common chillers use water in an external tower to cool the gaseous refrigerant in the condenser. After the heat is discharged, the refrigerant undergoes a phase change into a liquid, which is then recirculated back into the system.
Air Cooled Scroll Chiller
Water cooled chillers are generally more efficient than air cooled chillers
They operate more quietly than air-cooled systems
They are suitable for small and commercial scale cooling
Portable solutions are suitable for space-constrained facilities
Air cooled chillers use ambient air to remove heat from the refrigerant in the condenser prior to condensation and recirculation. In addition, a fan mounted on the unit helps to speed up the cooling process. Air-cooled chillers are suitable for applications where discharging heat is not a problem, as they tend to generate a lot of heat on site.
Portable solution for space-constrained facilities
Air-cooled chillers can be used for small and commercial scale cooling, depending on size and chiller capacity
They are cheaper to install and maintain than water-cooled systems
The heat discharged from the chillers can be used to heat the facility during cold periods, providing additional cost and power savings
Although the components of air-cooled and water-cooled chillers are largely the same (condenser, expansion valve, evaporator and compressor), the main difference lies in the way the refrigerant is cooled.
In an air-cooled chiller, the hot refrigerant entering the condenser is exposed to the atmosphere and the air releases heat before condensing back into liquid form. In a water-cooled chiller, on the other hand, the hot refrigerant gas is delivered to a water-cooled heat exchanger or condenser and water from a cooling tower is used to cool the refrigerant.
Water Cooled Screw Chiller
Industrial chillers can be further classified as 'vapour compression' or 'vapour absorption' types, depending on how the refrigerant is transported within the system. Take a closer look at how chillers work in these different system types.
A vapour compressor chiller uses a compressor to pump the refrigerant, thereby extracting unwanted heat from the process. The components of this system are the same as the absorption type - we have an evaporator, a condenser and an expansion unit. However, there is no absorption medium in the unit.
Unlike vapour compressor systems, vapour absorption chillers use a heat source to transport refrigerant around the system for cooling. The system has the same components as a vapour compressor chiller, but instead of a compressor there is an absorber, pump and generator.
The heat source can be heated with water or steam, the refrigerant can be a low Global Warming Potential (GWP) type, and the absorption medium can be a lithium bromide or ammonia solution. The heated water or steam helps to regenerate the adsorption solution.
Centrifugal chillers are very reliable vapour compression cycle chillers, ideal for medium to large cooling operations (from 150 to 6000 tonnes of cooling). They consist of the usual evaporator, compressor, condenser and expansion unit, but with an additional rotating impeller to compress the refrigerant and deliver it around the system.
Screw chillers are vapour compressor chillers which use a screw compressor to deliver the coolant into the system. Some of the main advantages are their compact installation, quiet operation, low maintenance costs and high energy efficiency. They are also ideal for high-rise buildings.
To discuss in detail whether an air-cooled chiller screw chillers, or a water-cooled chiller is right for you, please contact us.