Everything Need to Know How Does a Chiller Work

A chiller is a liquid cooler, which as in a direct expansion system, by heat exchange or either heats or cools. In this article, we are going to tell you how does a chiller work.

The Chiller as the main feature has:

-Keep the refrigerated liquid when it works in cold function.
-Keep the liquid heated in heat pump function.

Chiller as climate control:

The chiller as direct expansion units are placed outside the building. Inside the building will be placed the thermo-ventilated units called FAN-COIL that are like the indoor units of a direct expansion system.

The only connections between the internal unit and the external unit is a common hydraulic circuit closing a circuit.

The liquid treated in the outdoor unit cooled or heated and circulated driven by the pump included in the hydronic system, for all FAN-COIL units.

Finally, the FAN-COIL uses the water that flows through it, sending the resulting heat exchange (cold air or hot air), by means of a fan to the environment according to the user’s comfort demands.

Attention: Just like a conventional direct expansion system, it must be considered that it produces condensates due to the temperature differential.

The Chiller as a more versatile unit than a conventional air conditioning unit:

Versatility in the number of internal units: In a conventional direct expansion air conditioner the outdoor unit must be connected to the indoor unit for which it has been designed.

On the other hand, the Chiller can relate to an indefinite number of internal units (FAN-COIL), if remembering that the total power of all the units multiplied by a constant factor does not exceed the total power of the external unit. This factor determines how many FAN-COIL units can operate simultaneously to the most extreme condition without lowering the efficiency of the installation.

Versatility in the type of internal units: In a direct expansion air conditioner the electrical interconnection between the indoor and outdoor unit is essential. Each external unit corresponds to an internal unit in the systems of an indoor unit and an external unit. In the2x1, 3×1, 4×1 systems … the same thing happens. With a Chiller system you can connect many internal units of different types, floor-ceiling units, Cassette, Conduits,


Operating phase of Split type units (Direct expansion): Between the internal and external unit there is a refrigeration connection and an interconnection electricity and consequently a refrigeration cycle is carried out as we all know.

Compression of refrigerant-Condensation (Low pressure and decreases coolant temperature) – Coolant goes from gas to liquid state-Coolant expands and lowers its pressure and at the end of the capillary its temp. -Evaporation the refrigerant-Passes from liquid to gas state -Aspiration the compressor absorbs the gas and begins the cycle

Operating phase of the Chiller:

Between the indoor and outdoor unit there is no refrigeration connection only hydraulic and no electrical interconnection between the two units. The Chiller internally works as a direct expansion unit, but the refrigerant cooled or heated in the two refrigeration cycles is circulated by an exchanger through which it circulates in parallel through another tube and in the opposite direction or, in the same direction depending on the needs Water. For the phenomenon that we all know, there will be an exchange of energy from the hottest body to the coldest.

Difference between the Split system and the Chiller system: If one or more internal FAN-COIL units are running, it may be that the unit outside this stop. Because the internal unit takes advantage of hot or cold water that recirculates the water pump of the Chiller system to heat or cool the environment. The Chiller system keeps the circulating water temperature constant and if there is any temperature change in this per enzyme p below the SET POINT by differential temperature increases or lowers the water temperature.

Operation of a chiller liquid cooler for the conditionalize into of environments:

Traditionally the direct expansion air conditioner is an air-air system, because the outdoor unit (Condenser) takes advantage of the air circulation to condense the hot gas, and the air is also used by the internal unit (Evaporator) for the change of state (Both in cold function). The operating principle of a Chiller unit is like that of air-air, but it also uses water for the change of state, which could be defined as a water-air unit. The water is circulated in a forced manner on a temperature exchanger in which the change of state is made using the water factor and not the air factor for it. The water leaving the exchanger circulates through the hydraulic circuit to each of the FAN- COIL at a certain temperature, thus modifying the ambient temperature affected by said FAN-COIL, and returns to the exchanger to rectify its temperature again. A new temperature exchange between the water and the refrigerant is produced to be distributed again by all the FAN-COIL units. In conclusion: A Chiller is like a conventional direct expansion air conditioner but: -Condenser and evaporator are together in the same machine. -The evaporator does not cool the water in the environment but cools the water that comes from circulating through the internal FAN-COIL units to air-condition the environment.

Constructive features:

Electro pump: Centrifugal type of several stages, made in INOX AISI 319L. Silent and compact available for good distribution of water in buildings of different floors. The pump can work with mixtures of water and antifreeze such as glycol. Example for a model of48. 000 BTU

Switches: Connected electrically to the microprocessor, it controls the pressure difference at the end of the exchanger. Its function is to ensure that the exchanger is filled with liquid and that it passes through it with constant flow.

Expansion vessel: In INOX steel, it absorbs the blows caused by the pump and compensates for the thermal expansion of the water during operation.

Safety valve: Tarada at 3 bars. It serves to prevent breakage by overpressure of the hydraulic circuit.

Automatic air purge: For the elimination of air bubbles in the circuit.

Load and unloading fitting: To load and unload in the case of commissioning or special maintenance.

Heat exchanger: Coaxial type elastomer allows good operation at low temperatures (Allows dilation).

Microprocessor: The microprocessor is the internal thinking brain of the unit, manages and controls all the operation of the Chiller, new generation transmits specific algorithms, which allows that there is no accumulator within our hydraulic circuit for proper operation, ensuring the optimization of the consumption and reducing this with the consequent economic savings.

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