What is absolute humidity? Basically absolute means real value. It is the amount of water contained in a given mass of air at a given temperature. This means you can accurately detect the humidity in the air. Air density is an important criterion for determining absolute humidity. Absolute humidity (AH) is mathematically defined as AH = water vapor/air ratio.

What is a chiller? A chiller is basically a central means of heat exchange between inside and outside the building. A chiller performs two basic functions: to cool the air in the building and to provide dehumidification. Water enters the evaporator and condenser via external piping. The piping inside the tubing is surrounded by a chiller medium, which is a compressible gas such as Freon. As water circulates in the tubing, heat is transferred between the water and the chiller medium. The chiller comes in two stages of media pressure. First, the medium is fed to the condenser at high pressure by a compressor. When a medium is compressed, its temperature rises. The chiller medium then leaves the condenser through an expansion device that depressurizes the medium suddenly before entering the evaporator. When a medium expands in this way, its temperature decreases. The pressure change between these two phases is the key to the cooling provided by the chiller. Heat is removed from the air in

What are Dehumidifiers? Basically warm air has more humidity than cold air. The higher the humidity in the air, the lower the rate of evaporation of sweat. Since sweat evaporation is an important mechanism for cooling the human body, high humidity increases discomfort in warm weather. Good HVAC systems not only cool the building but also remove excess humidity. Condensation dehumidification is a process used to remove excess moisture from the air in HVAC systems. When warm, moist air passes over a cooling coil, its temperature drops to the point where the air can no longer hold all the moisture it contains. The moisture then condenses in the form of droplets on the coil which can be drained. Typically this is accomplished by coils that use chilled water to cool the building, and condensation is removed as these coils are formed.

What is a HVAC system? HVAC basically stands for Heating, Ventilation and Air Conditioning. And it is a kind of automation system used to handle the air quality and thermal comfort given to the human environment for living. It is based on thermodynamics, fluid mechanics and heat transfer. Just like the various types of automation systems, HVAC is also a type of automation system. It is an important part while erecting high-rise buildings, commercial complexes, industrial units, hospitals, parking units, hotels, etc., where air quality and thermal parameters need to be maintained so that the surrounding employees can live comfortably.

Video Management System (VMS)  Video management system is used in CCTV system. Video management system enable users to record and view video from CCTV. Video management system also known as video management software. Video management system collect video from camera and stores to storage device and also used in security system. Video management system can be the software components of a network video recording (NVR) and digital video recording (DVR). Digital Video Recorder (DVR) Digital video recording is a electrical device. Record video in digital format to a disk drive, USB flash drive, SD memory card, SSC or other local networked mass storage device . Network Video Recorder (NVR) Network video recorder is specialized computer system that include a software program. Network video recorder record video in digital format. Network video recorder store data and remote viewing. Network video recorder store image in HD format.

CCTV  Closed circuit television cameras (CCTV) used monitor or record image in specific location . CCTV store image in video format also CCTV provide security. CCTV monitoring image in real time in remote location and also known as video surveillance. CCTV monitor activity record information in video format. CCTV Camera Types Color and Monochrome Camera Camera Shape  Color and Monochrome Camera Color Camera  Color camera is send color image. Color camera is high cost compare to monochrome camera. Monochrome Camera  Monochrome camera is also called as black and white camera. Monochrome camera send image in black and white format. Camera Shape   Camera shape is many different types like cylindrical and box type, dome type, combination dome type .

Access Control System Access control system is electrical system. Access control system is automated approval for authorized person to enter area. Access control system is a advance security system for building and rooms. Access control system provide only authorize person access and this system is fully automatic system.  Access control system is most commonly used in door control. Access control system is fixable control system. Different example of access control system like bio-metric, RFID, door controllers.  Components of Access Control System Access Cards  Card reader  Keypads  Electrical Lock Alarm System  Field Panel  Access Control Software Access Cards  Access card is also known as ID card. Access card is a electronic key. Card reader  Card reader is read access card. Deck line or grant access. Open and closed door using control panel or card data. Keypads  Keypads also known as access control keypads. Keypads is another method for entry. Keypads is a numarical keypads used

Differentiate Between Water Tube and Fire Tube Boilers? Fire Tube Boiler  Hot flue gases flow inside the tube and water outside the tube. This boiler are generally internally fired. This boiler pressure limited to 20 bar. Fire tube boiler is low rate of steam production .  Fire tube boiler not suitable for large power plant. Fire tube boiler is high pressure and less risk. Fire tube boiler difficult to construct  Water Tube Boiler Water tube boiler is water flow inside the turbine and hot flue gases outside the tube. Water tube boiler are generally externally fired. These boiler pressure limited to 100 bar. Water tube boiler is higher rate of steam production  Water tube boiler is suitable for large power plant. Water tube boiler is high boiler pressure and high risk. Water tube boiler simple in construction 

Fire Alarm System (FAS)  Fire is the effect of the process of combustion of special type of chemical reaction. Chemical reaction occur in reaction of fire, fuel and oxygen Fire alarm system is warns people when smoke and fire is detected and ensure ultimate safety. Fire alarm system is used to keep people safe. Fire alarm system is designed to alerts us to take action in emergency, fire and smoke detected. Fire alarm system is active fire protection system that control all fire alarm module. Fire alarm system control panel linked to number of fire detection lines and manual call points. Fire alarm system is automatic function to detect fire. Fire alarm system receive signal from fire sensors and automatic transmit in to fire alarm panel. Fire alarm system having number of devices and devices work together. Fire alarm system detect a fire at an early stage and alerting and evacuating occupants. Fire alarm system is active auxiliary function. Fire alarm system is identifying and guiding

Hot Water System  Hot Water System use hot water to convey heat to a conditioned space The main components used in hot water system are  Boiler Terminal Equipment Water valve Expansion Tank  Two type boiler used in hot water system  Fire Tube Boiler  Water Tube Boiler  Fire Tube Boiler  Hot flue gases flow inside the tube and water outside the tube. This boiler are generally internally fired. This boiler pressure limited to 20 bar. Fire tube boiler is low rate of steam production .  Fire tube boiler not suitable for large power plant. Fire tube boiler is high pressure and less risk. Fire tube boiler difficult to construct  Water Tube Boiler Water tube boiler is water flow inside the turbine and hot flue gases outside the tube. Water tube boiler are generally externally fired. These boiler pressure limited to 100 bar. Water tube boiler is higher rate of steam production  Water tube boiler is suitable for large power plant. Water tube boiler is high boiler pressure and high risk. Water t

Significance of humidifier in AHU Humidification is often necessary in colder climates where continuous heating will make the air drier, resulting in uncomfortable air quality and increased  static electricity.  Various types of humidification may be used Evaporative dry air blown over a reservoir will evaporate some of the water. The rate of evaporation can be increased by spraying the water onto baffles in the air stream.  Vaporizer steam or vapor from a boiler is blown directly into the air stream.  Spray mist water is diffused either by a nozzle or other mechanical means into fine droplets and carried by the air.  Ultrasonic A tray of fresh water in the airstream is excited by an ultrasonic device forming a fog or water mist.  Wetted medium A fine fibrous medium in the airstream is kept moist with fresh water from a header pipe with a series of small outlets. As the air passes through the medium it entrains the water in fine droplets. This type of humidifier can quickly clog if the

Significance of damper in AHU A damper is a valve or plate that stops or regulates the flow of air inside a duct, chimney, VAV box, air handler, or other air-handling equipment. damper may be used to cut off central air conditioning (heating or cooling) to an unused room, or to regulate it for room-by-room temperature and climate control. Its operation can be manual or automatic. Manual dampers are turned by a handle on the outside of a duct. Automatic dampers are used to regulate airflow constantly and are operated by electric or pneumatic motors, in turn controlled by a thermostat or building automation system. Automatic or motorized dampers may also be controlled by a solenoid, and the degree of air-flow calibrated, perhaps according to signals from the thermostat going to the actuator of the damper in order to modulate the flow of air-conditioned air in order to effect climate control. An AHU typically has dampers that are used to control the amount of out- door air that enters the

Refrigeration Cycle The refrigeration cycle, sometimes called a heat pump cycle, is a means of routing heat away from the area you want to cool. This is accomplished by manipulating the pressure of the working refrigerant (air, water, synthetic refrigerants, etc.) through a cycle of compression and expansion.   Refrigeration, or cooling process, is the removal of unwanted heat from a selected object, substance, or space and its transfer to another object, substance, or space. Removal of heat lowers the temperature and may be accomplished by use of ice, snow, chilled water or mechanical refrigeration. The 4 main components of refrigeration cycle compressor condenser expansion device (expansion valve) evaporator Compressor Compression is the first step in the refrigeration cycle, and a compressor is the piece of equipment that increases the pressure of the working gas. Refrigerant enters the compressor as low-pressure, low-temperature gas, and leaves the compressor as a high-pressure, hi

VAV System In Variable Air Volume (VAV) systems, supply of cool air increases as the cooling load increases, and the air supply decreases as the load decreases. VAV systems are the most modern, energy efficient all air systems available for comfort air conditioning. VAV systems require less fan capacity than a comparable constant volume system because with VAV only the required air is used. Control of air flow in a VAV system is accomplished through an electronic device, which regulate the amount of supply air to the space in response to a proportional room/space temperature controller. Series Fan Powered VAV System In a series fan-powered variable air volume (VAV) system, each zone is conditioned by a box with a small fan that draws-in plenum return air and mixes it with supply air from a primary system. The primary system is similar to variable air volume (VAV), with the primary air supplied at a fixed temperature. Series fan-powered systems provide each zone with variable temperatur

Plate Heat exchanger A sandwich of plastic or metal plates with interlaced air paths.  Heat is transferred between airstreams from one side of the plate to  the other.  The plates are typically spaced at 4 to 6mm apart.  Can also be used to recover coolth. Heat recovery efficiency up to 70%. With a plate heat exchanger, heat cuts through the surface and separates the hot medium from the cold. Thus, heating and cooling fluids and gases use minimal energy levels. The theory of heat transfer between mediums and fluids happens when Heat is always transferred from a hot medium to a cold medium. There must always be a temperature difference between the mediums. The heat lost from the hot medium is equal to the amount of heat gained by the cold medium. Advantages of plate heat exchanger Improved temperature approach, true counter-current flow, 80-90% less hold-up volume. Low capital investment, installation costs, limited maintenance and operating costs. Less fouling, stress, wear, and corros

Air Handling Unit (AHU) An air handler, or air handling unit (AHU), is a device used to regulate and circulate air as part of a heating, ventilating, and air-conditioning  (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.  Air handlers usually connect to a  ductwork ventilation system that distributes the conditioned air through the building and returns it to the AHU. AHU operation is fundamental to the Commercial Building HVAC Control. Increased comfort and operational efficiency may be achieved through advancing the control of an AHU- resulting in more sales, reduced energy costs and satisfied customers.  An air handling unit (AHU) is used to calculate the energy consumption of heating and/or cooling (outside) air to a certain set point. This type is considered to be mainly used in multizone building for ventilation. There are two main types of air handling unit — t

Enthalpy and Entropy Enthalpy Enthalpy is the heat energy content of moist air. It is expressed in Btu per pound of dry air and represents the heat energy due to temperature and moisture in the air. Enthalpy is useful in air heating and cooling applications. The enthalpy scale is located above the saturation, upper boundary of the chart. Lines of constant enthalpy run diagonally downward from left to right across the chart. Lines of constant enthalpy and constant wet-bulb are the same on this chart, but values are read from separate scales. More accurate psychrometric charts use slightly different lines for wet-bulb temperature and enthalpy. Entropy Entropy is the measure of a system's thermal energy per unit temperature that is unavailable for doing useful work. Because work is obtained from ordered molecular motion, the amount of entropy is also a measure of the molecular disorder, or randomness, of a system. Entropy is defined as the measurement of degree of randomness or in oth

Comfort Parameters For Human Being Five major human comfort parameters are decided for this research study, which influence the indoor human comfort the most. The five parameters are namely thermal comfort, visual comfort, air quality, acoustic, and lighting. Temperature  humidity   flow  pressure  clean air  co2 % Temperature Sensor  RTD Thermocouple  thermistor RTD RTD (Resistance Temperature Detector) is a sensor whose resistance changes as its temperature changes. The resistance increases as the temperature of the sensor increases. RTD works by using a basic principle; as the temperature of a metal increases, so does the resistance to the flow of electricity. An electrical current is passed through the sensor, the resistance element is used to measure the resistance of the current being passed through it. Thermocouple  Thermocouple are the most common sensor types used to measure temperatures. These are preferred over the others for measurements because they avoid the tedious proce

Dew Point and Saturation Point in BAS Dew Point Dew point is the temperature to which air must be cooled to become saturated without changing the pressure.  Changing the pressure affects the vapor pressure and therefore the temperature at which saturation occurs. Thus, the dew point temperature is determined by keeping the pressure fixed. Changes in pressure slightly modify the dew point temperature. The dew point is useful in forecasting minimum temperatures, forecasting the formation of dew and frost, and predicting fog. When the dew point equals the air temperature, the air is saturated and the relative humidity is %100.   The dew point temperature tells us nothing about how many water molecules are in the atmosphere or how close the air is to a relative humidity of 100%. Saturation Point The saturation temperature is the temperature at which the refrigerant changes from a liquid state to a gas. The boiling point is the same as this. The saturation temperature of water at sea level

Security system in BAS Security System BAS can control when security systems are engaged and when they’re not. They can manage video surveillance, keyless entries, passcodes and remote access. Benefits of Security System Protection Deterrent to burglars Peace of mind Convenience and energy savings Reduced home insurance premiums Securing the BAS is an ongoing process, and the safety measures need to be followed regularly for its efficient performance. Appoint a team of network administrators to monitor the building management systems regularly. Adopt a holistic approach when installing all the components/systems in the buildings. Identify the vulnerable pockets and monitor them closely. Mark the areas where communication lines are running and monitor the installed physical security systems, such as CCTVs. Ensure that information technology systems have adequate firewalls. Take back-ups of all the data generated and secure it to prevent data theft.