28-08-2014, 12:01 PM
DEHUMIDIFIER A dehumidifier is generally a household appliance which reduces the level of humidity in the air, usually for health or comfort reasons, or to eliminate musty odour. Excessively humid air can cause mold and mildew to grow inside homes, both of which pose numerous health risks. Humid climates, or humid air within buildings, make some people extremely uncomfortable, causing excessive body perspiration that can't evaporate in the already-moisture-saturated air. It can also cause body moisture precipitation that can disrupt sleeping, create a situation where the cold pipes in this area begin to drip (from the condensation), and can prevent laundry from drying thoroughly enough to prevent mustiness. Lower humidity is also preferred because it limits the population of most pests, including clothes moths, fleas, cockroaches, woodlice and dust mites. Relative humidity in dwellings is preferably 30 to 50 percent. By their operation, dehumidifiers extract water from the conditioned air. This collected water (usually called condensate) cannot be used for drinking, so it must be discarded. Some designs, such as the ionic membrane dehumidifier, dispose of excess water in a vapor rather than liquid form. The energy efficiency of dehumidifiers can vary widely. Dehumidifiers are also used in industrial climatic chambers, to reduce relative humidity to levels conducive to processing of certain humidity-sensitive products. AHU (AIR HANDLING UNIT) An air handler, or air handling unit (often abbreviated to AHU), is a device used to condition 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. Sometimes AHUs discharge (supply) and admit (return) air directly to and from the space served without ductwork. Small air handlers, for local use, are called terminal units, and may only include an air filter, coil, and blower; these simple terminal units are called blower coils or fan coil units. A larger air handler that conditions 100% outside air, and no recirculated air, is known as a makeup air unit (MAU). An air handler designed for outdoor use, typically on roofs, is known as a packaged unit (PU) rooftop unit (RTU). The air handling unit (AHU) is one of the most essential and critical units to be considered when designing an air conditioning system. This air conditioner is designated by us and other industry manufacturers as an air handling unit. The importance of the air handling unit in the system is readily understood, as it modifies the air conditions for final treatment of air conditioned environments and is placed downstream of all other installed equipment. Both the construction layout and the physical location of the installed air handling unit means that it is extremely difficult to adjust at a later date to conditions much different from those established during the original selection process. For this reason, the equipment must be carefully and precisely selected. The front surface, and therefore the width and height of the equipment, is defined on the basis of the air flow rate.The type of fan and the motor can be selected on the basis of the designed static pressure. Difference between DEHUMIDIFIER and AHU in dehumidifier additional dessicant is used for removing excess moisture from air. whereas in AHU only air is supplied