Understanding Chiller Systems and Technicians

 The chiller industry can seem complex and daunting at first glance, especially when considering its extensive use in large commercial and industrial settings such as hospitals, office buildings, universities, and factories. However, the core components of these systems are quite similar to those found in residential HVAC units—only larger. This post will explore the chiller industry, the role of chiller technicians, the purpose of a chiller system, and the refrigerants used.

The Role of Chiller Technicians

Chiller technicians are specialists who work on large-scale refrigeration systems. They are well-versed in both HVAC and refrigeration principles, as well as the safety standards required in these industries. Most technicians in this field have prior experience working on smaller refrigeration systems and often transition into more commercial settings.

What Is a Chiller System?

At its core, a chiller system produces chilled water to regulate the temperature within a building. There are two main types of chillers: high-pressure and low-pressure systems. We'll delve deeper into the types of chillers in future posts, but in essence, chillers use refrigerants to cool water, which then circulates through air handling units (AHUs) to manage indoor temperatures.

Types of Refrigerants Used

Chillers use both primary and secondary refrigerants. Primary refrigerants change state between liquid and gas, facilitating heat transfer. Secondary refrigerants, like chemically treated water, do not change states and remain in liquid form throughout the process.

Water-Cooled vs. Air-Cooled Chillers

In the realm of chiller systems, the two most common types are water-cooled chillers and air-cooled chillers. Water-cooled chillers are more efficient and stable, making them the go-to choice for commercial buildings. Air-cooled chillers, on the other hand, are smaller and typically used in facilities without adequate water supply systems.

Heat Rejection Systems

Heat rejection systems are a key part of chiller operations. They remove heat from the building via three methods: cooling towers (open systems), fluid coolers (closed systems), and dry coolers (direct heat exchange). Each system has its advantages depending on the building's design and location.

Chiller Components and Operation

Chillers consist of several important components such as evaporators, condensers, compressors, and metering devices. The evaporator absorbs heat from water, which is then transferred to the air handling unit. The compressor circulates refrigerant through the system, and the metering device controls refrigerant flow, ensuring efficient cooling.

Air Handling Units (AHUs)

In large buildings, air handling units work in tandem with chillers to distribute cooled air. They include filters to ensure the air quality and chilled water coils to absorb heat from the air. AHUs play a crucial role in maintaining air balance and are often found in places where clean air is essential, like hospitals.