AIR CONDITIONER TYPES
CLASS NOTES FOR ENGINEERING
The air conditioning is an integral part of any home,
office, restaurant, cinema and industry. Making the right
selection is crucial. Comfort & energy consumption are
interrelated. Different cooling requirements use
different types of refrigeration units. Each has its own
advantages and disadvantages.
Domestic applications use window
and split units. Air cools the condenser
in such cases. Commercial applications use
factory assembled packaged units.
Water cools the condenser in these units.
Requirement of the Central air conditioning plant
is for large buildings . Water or evaporative cooled condensers are in use.
Room Air conditioners
A room air conditioner is a window air conditioner. It is portable and provides quick cooling. Cooling coil portion is inside. The compressor and condenser are on outer side. Unit is quiet. It picks room heat and disposes outside. These are for a single room. These units are cheap and have easy installation. It uses simple vapor compression refrigeration cycle. Cooling and dehumidification of air makes it comfortable in summer. It absorbs heat from inside the room and releases outside. Various capacities of the window air conditioners are 0.5, 1.0, 1.5, 2.0, 2.5 and 3.0 TR capacities. Its has limited cooling capacity. For more cooling requirement, shift to split air conditioner or central air conditioning unit.
SPLIT AIR CONDITIONERS
Split air conditioner is similar to window air conditioner. It consists of two parts. Cooling unit is inside the room. Installation of compressor and condenser is outside the room. Connect these two parts with insulated refrigerant piping. It uses long pipes. Long piping causes more pressure drop. Long pipes contain more joints and increase the chances of leakage. Higher principal and running costs make it costly. AC room looks good as there is no change in window. Noise making condensing unit is outside. These units do not use ducts. Mostly these are up to 3 tons capacity. Their installation requires expertise. Poor installation creates lot of problems.
Use of window and split air conditioners is for small cooling requirements up to 5 tons. Central air conditioning system is for cooling of more than 20 tons. Use of packaged air conditioners is for the cooling capacities in between 5 and 20 tons. The capacity of packaged air conditioners is 5, 10, 15 & 20 tons. Use these packaged units for libraries, small halls and restaurants. Space limitations also dictate its use. Mount these units on the ground or on the roof. Nothing is inside. It becomes convenient for the service engineer to attend repairs or replacement. Condenser, compressor and evaporator are all in one cabinet. These contain the equipment which generates cool air and distributes the cooled air through ducts. These use water cooled condensers. They typically blow cool air into the building through duct work. There are often several units on the roof of a one building. These packaged units are a single unit for heating and cooling. In appearance looks like an Elmira. Place the unit near the space requiring cooling. Connect water connection for the condenser.
Portable Air Conditioning Unit
It consists of a single cabinet. Placed inside a room. Heat exhausts through a hose going out of an exterior wall.
Central air conditioning plant
Main components of central air conditioning plants are compressor, condenser, expansion valve, evaporator, fans and blowers, filters louvers and ducts. Fresh ventilation maintains requisite level of oxygen in the air conditioned space. Air conditioning deals with temperatures above 0 C. One window air conditioner cools only one room. Cooling an entire building with window units require number of units. It increases the cost, repair and noise level. Central air conditioning plants use Fan coil units and Air Handling Units. It uses water cooled and evaporative cooled condensers. Water cooled condenser requires a cooling tower to cool the hot water of the condenser. Direct expansion type and chilled water systems are two different types of central air conditioning units. Central air conditioning system uses supply, return and branch ducts. Registers supply the conditioned air into the rooms. Place the unit outside at an isolated place. It suits for hotels, cinema, supermarket and a hospital.
Heating Ventilation Air Conditioning (HVAC)
HVAC controls climate of confined space as per requirements of persons or goods in it. HVAC system heats and cools the air in winter & summer respectively. It also maintains the indoor air quality (IAQ) & supplying fresh air. In winter, requirement is heating and humidification of air. In summer, it requires cooling and dehumidification of air. Year round air conditioning units are HVAC Units. These systems have become more popular. HVAC systems provide thermal comfort for occupants accompanied with indoor air quality. HVAC equipment includes heating, ventilation and air-conditioning equipment. Two types of HVAC systems are central and local. Central HVAC systems locate themselves in a room away from buildings and supply the conditioned air by ductwork layout system. Local HVAC systems locate themselves inside a conditioned space or adjacent to it and require no ductwork. Local systems include portable, window and split systems.
https://www.mesubjects.net/wp-admin/post.php?post=7902&action=edit Summary of Air Conditioning