The air around us is warmed up by everyday activities such as breathings, washing and drying clothes, cooking food, running electric motors and using electric lights. The composition of the air around us can also be changed by: chemical pollutants, pollen, dust, tobacco smoke and odors. These changes will make the air stale if it stays in a confined space. This may make us feel hot and sticky and can make us less efficient at work. To stop the air around us from being stale we need ventilation. Ventilation is the movement of air in such a way that fresh air replaces stale air in an enclosed space. Effect of Ventilation
* Removes excessive heat from enclosed spaces and replenishes the oxygen supply. * Lack of ventilation causes dampness and heat. For e.g. if a room filled with people is badly ventilated and contains still, humid air, sweat cannot adequately evaporate quickly enough from their skin and causes a rise in body temperature. Features that help to ensure good ventilation:
* Open windows – ventilation may simply involve opening windows to allow stale air out and fresh air in. This is most effective if windows are opened in both lower and upper levels of a building, as natural convection currents will make warmer, stale air leave the building at the top to be replaced by colder, fresher air at the bottom. * Fans – whether mounted on ceilings or standing, fans assist in the movement of air by replacing stale air with fresh air. * Fancy bricks – also help to increase ventilation in rooms and buildings. * Air conditioner – used to prevent the inside of a building from becoming incredibly hot. It maintains the temperature of the air within a quite narrow range and prevents a rise in humidity by pulling heat out of the indoor air and thereby cooling the room. * Humidifiers – devices used to increase or maintain the humidity of the air.
The air conditioning unit:
An air conditioning unit consists of 3 main parts:...
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