The term Air Handling System' refers to the equipment where air is conditioned to an acceptable level for distribution within the building. An air handling unit often abbreviated as AHU is a very important component of central-air-conditioning system. It is responsible for drawing return air from the indoor spaces, mixing it with outdoor air, conditioning it to the acceptable level for distribution within the building. The modular packaged equipment offered by various manufacturers is pretty standard. HVAC designers can simply spec the performance requirements and pick and choose from a wide...

Most people think the air conditioning system's job is just to add "cold" air to the space. Actually air-conditioning is a process to control temperature, humidity and air quality. Engineers define the process as one in which a system of mechanical components - usually a compressor, a fan, condenser coil, evaporator coil and a chemical refrigerant - extracts heat from indoor air and transfers it outside, leaving the cooled indoor air to be re-circulated. The cleaning function of air conditioners is performed by filters. Diverse geographical and operating conditions require considerably...

The prime requirement in respect of the indoor climate in a building is that room temperature should be at a comfortable level, regardless of the weather conditions outside. As soon as the ambient temperature is lower than the indoor temperature, heat flows out from the building through its boundary surfaces (the building envelope). At the same time, the building also loses heat through air infiltration, i.e. the inward leakage of outdoor air into the building through gaps and cavities in walls, roofs, doors and windows. Bearing in mind the fact that the indoor temperature in most buildings...

Successful Heating, Ventilating, and Air Conditioning (HVAC) systems are the key to successful buildings. Because each building is different, it is very important to choose a system that is right for the facility. Proper selection of the HVAC system is a crucial decision for any new project and the decision depends upon a number of factors like how large area needs to be cooled, what is the application, what kind of total heat is generated inside the enclosed area, the developer's preference - initial installation cost, aesthetics, and long term maintenance and life cycle costs etc etc. The...

The HVAC systems are designed for peak conditions. Because these conditions prevail only for small period in a year, the HVAC equipment must operate most of the time at lean capacity. The function of the control system is to adjust the equipment capacity to match the load. Automatic controls are necessary not only to achieve the design conditions in the conditioned space but are also required for efficient operation of the HVAC system. The main parameters to be controlled in air conditioning system are temperature, pressure, humidity, air quality and thermal energy distribution. This 6 -hour...

One of the basic requirements of the air conditioning and refrigeration system is to reject heat to the outdoors. The refrigerant chillers come in two different forms: An air-cooled chiller uses the flow of outside air across the condenser to remove or reject heat from the chiller. Air-cooled chillers typically have the condenser mounted on the roof or somewhere outside the facility while the evaporator can either be inside or outside the facility. Water-cooled chillers are typically 100 tons or greater and use water to remove the heat from the condenser. Water-cooled chillers are typically...

Compressed air has many applications in industry. Delivering compressed air to a manufacturing facility is an expensive operation and it requires costly equipment that consumes significant amounts of electricity and needs frequent maintenance. Roughly 80 to 90 percent of the electricity used to operate compressed air systems is converted to low-temperature waste heat. This lost energy can quickly add up, each year costing individual facilities as much as double the purchase and installation cost (first-cost) of the entire system. The ideal time to think about your compressed air system is...

VRF (Variable refrigerant flow) is an air-condition system configuration where there is one outdoor condensing unit and multiple indoor units. The term variable refrigerant flow (VRF) refers to the ability of the system to control the amount of refrigerant flowing to the multiple evaporators (indoor units), enabling the use of many evaporators of differing capacities and configurations connected to single condensing unit. The arrangement provides an individualized comfort control, and simultaneous heating and cooling in different zones. Currently widely applied in large buildings especially...

A "green" building is a building that is energy and resource efficient, non-wasteful and non-polluting, flexible and adaptable for long-term functionality, easy to operate and maintain, and are supportive of the productivity and well being of the occupants. So-called green buildings are constructed or renovated under sustainable development, a design process that reduces the harmful impact on natural resources and looks at the life-cycle costs of the facility. Historically, how to define and standardize the green building is a long term challenge until the advent of Leadership in Energy and...