Application: HVAC

What is HVAC?
HVAC (heating, ventilation, and air conditioning) is the technology of indoor and vehicular environmental comfort. Its goal is to provide thermal comfort and acceptable indoor air quality. HVAC is important in the design of medium to large industrial and office where safe and healthy building conditions are regulated with respect to temperature and humidity, using fresh air from outdoors. HVAC systems can provide ventilation, reduce air infiltration, and maintain pressure relationships between spaces. The means of air delivery and removal from spaces is known as room air distribution. Ventilation is the process of "changing" or replacing air in any space to provide high indoor air quality which involves temperature control, oxygen replenishment, and removal of moisture, heat, dust and carbon dioxide. Ventilation removes unpleasant smells and excessive moisture, introduces outside air, keeps interior building air circulating, and prevents stagnation of the interior air. Ventilation includes both the exchange of air to the outside as well as circulation of air within the building.

HVAC (Heat Ventilation and Air conditioning),it include modulating controls, sequence control, Alarms indication Air handling unit (AHU) – a central unit consisting of a blower, heating and cooling elements, filters, etc. that are in direct contact with the airflow Chiller – a device that removes heat from a liquid. The cooled liquid flows through pipes and passes through coils in air handling units, FCUs, etc. Damper – a plate or gate placed in a duct to control the overflow.

Key Benefits of Automation in Utilities:
HVAC system is use for the human comfort which is to be done with Automation system. Basically HVAC system is consists of AHU and Chillers. Same were required for the Air cooling supply and maintaining the Temperature and humidity of the Room.
This project is related to Building management system and major areas are:

• AHU

An air handling unit (AHU) is a device used to regulate and circulate air as part of a HVAC system. An air handler is usually a large metal box containing a blower, heating or cooling elements filter racks or chambers, sound attenuators, and dampers. AHUs usually connect to a ductwork ventilation system that distributes the conditioned air through the building and returns it to the AHU.


• Chiller plant

The chillers are used to serve the chilled water to the building and to maintain the temp, humidity of the building by controlling the Air handling units. Contents of chiller plant are mentioned in the Chiller plant section. We have the 10 chiller sets with their respective chiller primary and secondary pumps. The primary pumps takes the water away from the heat exchange via the expansion tank which is fed into the chiller and the secondary pumps are used to pass the chilled water from the chiller to the building. The condenser water pump is used to feed the water from cooling tower to the chiller and re circulated the same to CT. The basic operation of this plant is to control the return water temp as compare to the set points. To maintain the temperature we have stage up or stage down the chiller operation. Heat exchangers are used for the same to maintain the temp. The AHU contains the Supply fans, return fans, cooling and heating coils, dampers (fresh and exhaust air), temperature and humidity sensors. AHU takes the fresh air from the fresh air damper and it mix with the return air (re circulated air) of room and passes through the filters. After filter Heating or cooling coils are used where the Chilled water supply and return lines are connected and then the supply fan is used for the circulation of air in to the room. To maintain the temp of the room heating & cooling processes are used as required.

Chillers system is operated through cooling towers and cooling water is supplied to AHU by using Primary and secondary pumps to cool the Air of Buildings.