Chiller systems comprise heating systems, ventilation, and air conditioners to be used in air balancings such as controlling the level of humidity and temperature. Modern buildings are fitted mostly to create good working conditions regardless of the external climatic condition. Workers and staff working in the building have a great expectation that the building's HVAC systems will function as expected.
Chillers are an essential part of commercialized modern buildings such as hospitals, schools, hotels, industries, and sports arenas. The HVAC consumes a large amount of power in most organizations. Generally, a chiller is used for the facilitation of the transfer of heat from the internal environment to the external. Chillers can be described as a heart due to the function it performs of thermoregulation in an organization.
Working on a chiller system:
A chiller works under the principle of air compression. The chiller provides a continuous flow to the cold side of the coolant at the desired temperature of mostly about 10 C. Then the coolant is pumped through the process to extract heat to one side of the facility then the warm air is returned to the water for cooling and the process is continued.
A chiller uses a vapor compression principle to connect the water process through the system across a device called an evaporator. The refrigerator then circulates through the evaporator, across the compressor through the condenser, and then the expansion device of the chiller. It is then followed by a thermodynamic process in each level above the level of the chiller. The evaporator works as a heat exchanger to transfer the heat captured to the refrigerator. During the heat transfer process, the refrigerant evaporates and converts the low-pressure liquid to vapor as the coolant reduces the temperature.
The compressor has different functions to perform as the refrigerant has flowed into the compressor. To begin with, it removes refrigerant from the evaporator this ensures that the temperature remains as low for convenient absorption at the appropriate rate. Then it increases the pressure in the outgoing vapor to retain temperature as high as possible to be able to release the heat as it reaches the condenser. The refrigerant returns to the condenser in the liquid state. The latent heat of vaporization ( L.H.V ) changes the refrigerant from vapor to liquid.
Types of chillers;
The transfer of latent heat from the liquid to vapor is done using two mediums, liquid, and air.
An air-cooled condenser uses a motorized blower to pump air across the grid of the lines of the refrigerant. For air-cooled condensers to work effectively, they require the heat of 35C and below.
A water-cooled condenser works under the same principle as the air-cooled condenser but needs two steps to complete the heat transfer. Heat moves into the condenser water from the refrigerant vapor. The warm water is then pumped into a cooling tower where the heat is eventually released into the atmosphere.
Water-cooled chillers contain a condenser connected to a cooling tower. They are mostly used for medium and large installations that have sufficient water supply. Water-cooled chillers produce a reliable performance for commercial and industrial air conditioning. Water-cooled chillers have a different range of sizes from small capacity to the world’s largest megaton capacity. It may include facilities such as airports, hospitals, and shopping centers.
A typical water-cooled chiller uses recirculating condenser water from a cooling tower to condense the refrigerant. A water-cooled chiller comprises a refrigerant that is reliant on inflowing condenser water temperature, which operates relative to the ambient wet-bulb temperature. The wet-bulb temperature is usually lesser than that of the dry-bulb temperature, and the refrigerant condensing temperature that is in a water-cooled chiller can also function slightly lesser than in an air-cooled chiller. Water-cooled chillers, therefore, run more competently.
Water-cooled chillers are fitted indoors to protect them from external environmental factors. They, therefore, have a long lifespan. An extra cooling tower system may need an extra installation expense as well as maintenance.
Air-cooled chillers depend on a condenser chilled through the environmental air. Air-cooled chillers therefore may be found in smaller or medium fittings that may have space constrain. An air-cooled chiller may represent a practical scenario while the water represents a rare resource.
An air-cooled chiller features paddle fans that suck ambient air over a finned coil to shrink the refrigerant. The compression of vapor in the air-cooled condenser allows the transfer of heat to the air.
Air-cooled have the advantage of having lower installation costs and meeker maintenance that may result from its ease as compared to water-cooled chillers. Air-cooled chillers inhabit lesser space but are fitted usually on the outside of a premise. The outside environment favors its practical lifespan.
air-cooled chillers are environmentally friendly thus reducing upkeep costs. They are relatively simple and have reduced space requirements which produces a major advantage in the majority of their fixings.
Maintenance of chillers
The cost of chiller maintenance is mostly in the consumption a large part of a building’s utility bills, especially electricity.
Chiller systems work more efficiently when there is proper ongoing maintenance that is done frequently. Organizations recognize this value and have taken steps to make it a part of their daily facility management schedule. common best practices for chiller systems to run efficiently may include:
Inspection and cleaning of the condenser coils. When there is heat transfer, it has a great effect on chiller systems and remains may remain to be essential in the production of the efficient chiller process. There should be routine maintenance to inspect the condenser coils from the clogs and for free air passage.
Maintenance of a refrigerant charge. A chiller’s cooling system depends on efficient refrigerant planes. Maintaining proper refrigerant charges greatly impacts energy efficiency by reducing cooling costs.
Maintaining the condenser water: Condenser water coils used with cooling towers should maintain a proper water flow. There should be no dirt like sand, solids, or any other foreign materials that may affect the condenser water loop.