DX Chiller vs Absorption Chiller: Which Cooling System Makes More Sense for Your Facility?

When facility engineers compare cooling options, the difference between DX and chiller systems comes up early and for good reason. These are two fundamentally different approaches to the same problem, and choosing the wrong one creates operational and financial consequences that compound over a 20–30 year system lifespan.

How Does a DX Chiller Work?

A DX chiller Direct Expansion cools air or process fluid by expanding refrigerant directly at the point of use. The refrigerant absorbs heat as it evaporates, travels to a remote compressor and condenser to reject that heat, and returns to repeat the cycle.

The key distinction: in a DX system, the refrigerant itself reaches the load. There is no intermediate chilled water loop. This makes DX systems compact and fast to commission but it distributes the entire refrigerant charge across the facility, requiring periodic servicing of compressors, expansion valves, and refrigerant pipework.

How an Absorption Chiller Works

An absorption chiller specifically BROAD's lithium bromide-water vapour absorption system replaces the compressor with a thermal-chemical process. Water is the refrigerant. Lithium bromide is the absorbent. The cycle operates under deep vacuum where water evaporates at low temperatures, producing cooling. No electricity is needed for the core refrigeration process only auxiliary pumps and controls.

The Core Difference Between DX and Chiller Systems

The fundamental difference between DX and chiller technology is where and how cooling is produced. DX systems bring refrigerant to the load efficient for distributed, smaller loads, but mechanically dependent on the compressor. Absorption chillers produce chilled water centrally and distribute it thermally driven, with no compressor to fail, maintain, or replace.

DX vs. Absorption: Direct Comparison

What Is the Full Form of DX in DX Cooling?

DX stands for Direct Expansion the direct evaporation of refrigerant at the cooling coil, without an intermediate fluid loop. A central chilled water system including all BROAD absorption chillers produces cooling centrally and distributes chilled water to air handling units or process exchangers.

For facilities where space is constrained and loads are under 150 TR, DX remains a practical choice. For continuous industrial loads above 200 TR, the chilled water distribution model of absorption technology offers better efficiency, lower lifecycle cost, and no refrigerant compliance burden.

Direct-Fired Absorption: When No Waste Heat Is Available

For facilities without existing steam or exhaust infrastructure, BROAD's direct-fired absorption chiller uses a natural gas, LPG, or diesel burner to heat the generator directly achieving COP 1.2–1.35. Even without waste heat, this eliminates electrical compressor dependency and reduces carbon intensity compared to grid-powered DX alternatives.

When BROAD Absorption Chillers Are the Stronger Choice

DX systems are appropriate for loads under 150 TR with distributed points and no accessible thermal energy. BROAD absorption chillers are the stronger choice for continuous industrial loads above 200 TR with any available thermal energy waste steam, generator exhaust, hot water from engine jackets, or direct fuel.