Permeability Permeability is the property of a material to allow fluids (such as water, water vapor or oil) to diffuse through it to another medium without being chemically or physically affected. Permeability causes deterioration of material longevity and acceleration of the corrosion process. It is defined as the ease with which water flows through the soil. Fine grained materials are less permeable. All organic forms of barrier protection are permeable to some degree, and once the protective coating is penetrated, its corrosion resistance is compromised. When coating deteriorates, its permeability to oxygen or moisture increases, and as a result the corrosion rate increases. Therefore, permeability leads to coating failure. Permeability is a measure of how easy it is for water, air and other substances to enter a material. Concrete contains pores that allow these substances to enter easily. Larger pores allow easier entry, while smaller pores decrease the rate at which these substan

Mechanical Properties of Soil Soil is a granular medium that varies in composition from organic peat to gravel and that may contain various amounts of water. The soil physical system is continually being subjected to external forces and is, therefore, dynamic. These external forces may be environmental (climate, plants, animals, and micro-organisms) or mechanical (forces applied by man using some type of machine). The specific reaction of the soil to these forces is of interest. The forces provide the means for changing soil from one condition into another and the reaction indicates the kind and degree of change. If one is to be able either to maintain a soil condition or to change it to a more suitable condition, he must first have an understanding of soil behavior; this behavior must eventually be properly described. Soil conditions and properties, widely varying types of forces, and widely varying types of behavior must all be included in any description before the description can b

Anemometer   An anemometer is a device used for measuring wind speed and direction.  An anemometer is an instrument used to measure the speed of the wind, which is a common weather station instrument, or to calculate any form of current gas. The basic classification of anemometers depends on the measurement of the velocity of wind and the measurement of the pressure of the wind. The 5 major types of anemometer are Cup anemometer Hotwire anemometer Windmill anemometer Laser Doppler anemometer Sonic anemometer The anemometer definition is a device used to measure wind speed. Anemometers report wind speed in miles per hour (mph), kilometers per hour (kph), meters per second (m/s), or knots. Anemometers measure wind speed by the amount of wind pressure against a surface, such as a cup or a propeller, or by using sonic pulses. A mechanical anemometer contains a wheel with cups or a propeller at the end of the spokes of the wheel. One of them contains a magnet.  Each time the magnet passes a

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