DEHUMDIFIER
2.1 Dehumidifier introduction
A Dehumidifier is a home appliance which reduces the level of humidity in the air usually for health comfort condition or eliminate musty odor from atmosphere. It is applie for removing moisture from the air as for lowering the humidity in room.
Dehumidification is combination of absorption and regeneration process carried out alternatively in given time.
2.2 CLASSIFICATION OF DEHUMIDIFIER
2.2.1 Mechanical Dehumidifier
Mechanical dehumidifier is work by moist air of refrigerated coil with a fan and compressor. The cold evaporator coil of the refrigeration device which is condenses the water which moisture is removed then the air is reheated by the coil. The reheated air is released into the surrounding room. This
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The design is simple and advantages of being silent compare to with Mechanical Dehumidifier. It is less Coefficient of Performance and this is used for small dehumidifier. Ice making is difficulty with refrigeration dehumidifiers. Fig 2.2.4 Thermoelectric dehumidifier
2.2.5 Desiccant Dehumidification
A process uses a Moisture absorb material is also called desiccant. which is uncovered to the surrounding air to be cooled and dehumidifier. The humidity absorbing material is move to a different place where it is recharge by reheating air.
Dehumidifier is work on absorption principle are specially for high humidity level at low temperatures. They are used in industry and commercial and residential building because humidity levels below 35% can be achieved.
Lack of compressor parts desiccant dehumidifier is lighter in weight and silent in operation than Mechanical Dehumidifier. Desiccant dehumidifier can also operate at lower temperature than Mechanical dehumidifier the unit lacks coils which are unable to extract moisture from the air at low
Since the evaporator coil is responsible for making the air in the system cool, it’s an incredibly important part that must always be in working condition. It’s job is to turn the coolant in the unit to a gas form, which then cools down the coil. When warm air passes over this coil, it becomes chilled before passing through all the vents in your home.
Norbert Rillieux invented the triple effect vacuum evaporator. The "triple effect" is for the multiple things that the system does all at the same time. The "vacuum" is for the vacuum of air that is used in the system, and the "evaporator" is for the sugarcane liquid syrup that is heated and evaporated into regular sugar. The actual system is somewhat complicated, so please see the picture that is provided.
In warmer climates such as Egypt they used techniques as evaporative cooling, “if water is placed in shallow trays during the cool tropical nights, its rapid evaporation can cause ice to form in the trays, even if the air does not fall below freezing temperatures”. Although refrigeration developed in the 18th century it wasn’t until the mid-19th century when the first refrigerator built using vapor technology was build by American John Gorrie in 1844. A few years later commercial refrigeration was introduced as well as vapor compression technology which was the beginning of our modern refrigeration. Later that century ammonia was popularized as the evaporation chemical in refrigeration. All the trials and tribulations of refrigeration where all stepping stones to the 20th century and the introduction of modern refrigeration as we know it
The American Council for an Energy-Efficient Economy (ACEEE) stated that choosing a machine that lowers water increases efficiency. However the size machine chosen also plays a role. Most conventional clothes washers use approximately 40 gallons of water per use however large capacity efficiency models use less than 25 gallons per cycle. Additional savings can be found by switching to high efficiency elect...
Process da: This low temperature liquid then enters the evaporator where it absorbs heat from the space to be cooled namely the refrigerator and becomes vapour
Refrigeration Refrigeration is defined as “The process of removing heat from an enclosed space, or from a substance, to lower its pressure.” (First website given in bibliography) In simpler terms, it is removing heat from states of matter in order to keep them cooler. The basic need for refrigeration is to cool food and beverages, as they often get spoilt if the temperature is high. Before actual refrigerators and other such mechanical systems were introduced, it was very common for people to cool their food with ice and snow.
In thermoelectric cooling Peltier’s effect is used to cause heat flux between the junctions of different types of materials. A Peltier heater/cooler transfers heat from one side of the device to the other by consuming electrical energy. This device is also known as a Peltier device, Peltier heat pump, solid state refrigerator, or thermoelectric cooler (TEC). Since there are more economical and easy ways of achieving cooling, Peltier’s devices are mostly used for cooling purposes. However, since a single device can be used for both heating and cooling, the desirability of Peltier’s device is more. By connecting a thermoelectric refrigerator to a DC voltage, one side of the peltier device cools while the other stays warm. The effectiveness of cooling depends on the amount of current and how well the heat is removed by the pump from the hot side. Peltier coolers and thermoelectric generators are exact opposites of each other. Peltier cooler uses power to generate temperature difference, whereas, thermoelectric generator uses temperature difference to generate power. Both the above mentioned devices have operations closely related to one another (both are thermoelectric effect applications), and therefore their constructions, raw materials used and designs are somewhat similar.
... temperature of 112 0C also and a pressure 2.5 bar. Cooling water is used to condense the vapor exiting column. Remaining methane and hydrogen are separated in reflux drum where the vapor stream is combined with other gases streams. The overhead of first and second separator are combined to form fuel gas. The liquid stream exiting in the bottoms of the reflux drum is pumped at pressure of 3.3 bar for discharging pressure. The pump stream is separated in two streams. One stream is to feed to tray one of the column and the other one stream is cooled down to 38 0C in heat exchanger. Then, the cooled product stream is sent to storage.
The hair dryer uses an electric fan to blow air across a heating coil; as the air passes through the dryer it heats up. When the warm air reaches wet hair it helps evaporate the water.
Moulds that grow on grain are sensitive to the relative humidity of the ambient environment. A relative humidity level of below 65% can reduce the growth of mould whereas a relative humidity level of below 85% can reduce bacterial growth, both of which causes significant spoilage of food (Nellist 1998). Therefore, food dehydration process is carried out to remove the moisture of which microbial growth is accelerated and promoted.
For much of the modern day world, refrigeration has taken on a very big role in everyday life for the average person. Many advances in the technology of refrigeration have occurred over the last couple hundred years. These advances helped to make daily human life easier through cooling, storing, and conserving food as well as other goods. However, much of the history that went into creating this common household appliance is overlooked and undervalued by those who have access to it every day.
Desiccators are sealed boxes containing material/desiccants used to preserve moisture-sensitive items. A common use for desiccators is to protect materials from getting moisture in it and from
A washing machine conjointly referred to as a laundry machine, garments washer, or simply washer could be a machine to scrub laundry, like clothing. The term is generally applied to machines that use water because the primary cleansing resolution critical cleaning. All laundry machines work by using mechanical and thermal energy.
The simultaneous heat and mass transfer to changes the temperature of the wet solid to evaporate its surface moisture and the transfer of moisture to the surface of the solid for subsequent evaporation from the surface to the surrounding atmosphere take place during drying processes. Normally, the hot air or combustion gases surrounding the feed are the drying medium. The psychrometry and the use of humidity charts determine the actual quantities of air required to remove the moisture liberated by evaporation. During heat transfer to a wet solid, the temperature Gradient developed within the solid and the moisture evaporation from the surface become the driving force for migration of moisture from within the solid to the surface, which occurs through diffusion, capillary flow, internal pressures due to the shrinkage during drying, and repeated and progressive vaporization and re-condensation of moisture to the exposed surface in the case of conduction type indirect drying. An appreciation of this internal movement of moisture is important when it is the controlling factor, as it occurs after the critical moisture content, in a drying
As air within the building gets warmer it becomes less dense and lighter. This means that warm air has a tendency to rise. Cooler air from outside is introduced into buildings at a lower level, as this is warmed by sources of heat within the building and it then rises through the building to escape out through openings at high level . The diagram below demonstrates how this method works.