HVACHeating, ventilating and air conditioning (HVAC) is elucidated as the concurrent control of temperature, humidity, energy, air motion and air quality within a confined location for enhancing process efficiency. Again, the management of pressure in the conditioned environment pertaining to surrounding locations is also significant. The noise level related to the air conditioning equipment is also a critical factor. From an engineering perspective, the definition refers to the lowest life-cycle cost of conditioning the air by revamping equipment to accomplish the distinct process application with the least operating and maintenance cost.
Types of HVAC
Cooling Only Split-System
A split system is an interface between an indoor air handling unit and an outdoor condensing unit. The indoor air handling unit comprises of an air fan, air-to-refrigerant heat exchanger and the expansion device. These systems can be installed in residential/commercial buildings. They have a high energy efficiency rating (EER). HVAC producers are expected to deliver a seasonal energy efficiency rating (SEER).
Cooling Only Packaged-System
A packaged system is a distinct unit having various components elucidated in the split system. The unit be established in an external environment while air from the interiors is “ducted” from the building to the packaged system via an air distribution system. The SEER rating of such units vary between 10 to 18.
Heat pump is similar to cooling only systems with one difference – a specific valve in the refrigeration piping facilitates the refrigeration cycle to be managed in reverse. A cooling only system keeps the internal air cool and rejects heat externally. An additional electric resistance heater can be used to support the heat pump at less external temperatures. In locations with cold climate, heat pumps would need a defrost period (electric heater being the only way of heating the internal environments of building).
Chilled Water System
In such a system, the liquid water is transmitted across the building to “chilled water coils”. The liquid water has to be maintained at a certain minimum temperature; hence a cooling plant is needed. The plant is also known as the chiller plant.
Window Air Conditioner
It is installed in a window. It can cool marginal space and cannot be used for rooms/zones.
Packaged Terminal Heat Pump
It is a window mounted air conditioner and is installed in a sleeve positioned in the external wall of a building. It leverages the external air as the source of heat when the temperature drops and as heat sink when the temperature increases.