Industrial Attachment

                                                       INDUSTRIAL  ATTACHMENT 

Date: October  in 4^th  week                                                  By: Md Nazim Uddin

Place: Zamil Air Conditioner’s India Pvt.Ltd

              Auckland Place ,4^th Floor ,4B Kolkata, West Bengal, India 

Documentary Subject: Described in Air conditioner 

                                             Air Conditioner short from  AC .AC is the process of removing  heat and moisture from the interior of an occupied and also comfort occupied. Air Conditioning also used to cooling and dehumidify rooms filed with heat producing electronic devices, such as computer servers power and pilferers and even to display and store some delicate products such  as art work .

In the most general since ,Air Conditioning  can refer to any  from of  technology that modifies the condition of air humidification cooling ,cleaning ventilation or air .Its system is which cool air .In construction and air conditioning is referred to NVAC .

Refrigeration Cycle :

                               Next page pencil drawing .

v  Condensing Coil

v  Compressor

v  Evaporator Coil

v  Expansion

The  most important element refrigeration cycle .

Circulating refrigerant vapor enters the compressor ,where its pressure and temperature are increased .the hot compressed refrigerant vapor is now at temperature and pressure at which it can be condenser and is routed through a condenser .

The condensed pressurized and still usually somewhat hot liquid refrigerant is next routed  through an expansion valve .

The cold refrigerant is then routed though the evaporator .

v  Compressors: The purpose of the compressor is to circulate the refrigerant in the system under pressure, this concentrates the heat it contains.

ü  This pressure buildup can only be accomplished by having a restriction in the high pressure side of the system. This is a small valve located in the expansion valve.

The compressor has reed valves to control the entrance and exit of refrigerant gas during the pumping operation. These must be firmly seated.

ü  An improperly seated intake reed valve can result in gas leaking back into the low side during the compression stroke, raising the low side pressure and impairing the cooling effect.

ü  A badly seated discharge reed valve can allow condensing or head pressure to drop as it leaks past the valve, lowering the efficiency of the compressor.

Two service valves are located near the compressor as an aid in servicing the system.

ü  One services the high side, it is quickly identified by the smaller discharge hose routed to the condenser.

ü  One is used for the low side, the low side comes from the evaporator, and is larger than the discharge hose

The compressor is normally belt-driven from the engine crankshaft. Most manufacturers use a magnetic-type clutch which provides a means of stopping the pumping of the compressor when refrigeration is not desired.

v  Condensers & Condensing Unit:

                                                                               Our systems benefit from reduced costs, increased efficiencies and low environmental impact. Combining the latest technologies of EC fans and remote electronic expansion valves, efficiencies are dramatically increased. Designed with space claim and performance at their heart, an air conditioning condenser and condensing unit can be installed with minimal space claim and are low in weight.

Our condensers and condensing unit range rang is also hood friendly. High sound insulation ensures that operating conditions are maintained without disturbing surrounding areas

v  Evaporation: 

                                         Ever wondered why you feel cooler by the ocean or a river? You feel cooler because as hot air blows across the water, it causes some of the water to evaporate and absorb the heat. The air is cooled by this evaporation process and so becomes a “sea” breeze.

Evaporation air conditioner works the same way. Hot air enters the cooling unit on your roof where it is filtered and cooled as it passes through specially designed moistened . A fan then blows this beautifully cooled air throughout your home.

Hot air in the house is forced out through open windows and doors providing your entire home with a complete change of air at least every two minutes.

v Expansion

                                The expansion valve removes pressure from the liquid refrigerant to allow expansion or change of state from a liquid to a vapor in the evaporator.

The high-pressure liquid refrigerant entering the expansion valve is quite warm. This may be verified by feeling the liquid line at its connection to the expansion valve. The liquid refrigerant leaving the expansion valve is quite cold. The orifice within the valve does not remove heat, but only reduces pressure. Heat molecules contained in the liquid refrigerant are thus allowed to spread as the refrigerant moves out of the orifice. Under a greatly reduced pressure the liquid refrigerant is at its coldest as it leaves the expansion valve and enters the evaporator.

Pressures at the inlet and outlet of the expansion valve will closely approximate gauge pressures at the inlet and outlet of the compressor in most systems. The similarity of pressures is caused by the closeness of the components to each other. The slight variation in pressure readings of a very few pounds is due to resistance, causing a pressure drop in the lines and coils of the evaporator and condenser.

Two types of valves are used on machine air conditioning systems:

ü  Internally-equalized valve - most common

ü  Externally-equalized valve special control

Refrigerants:

                         The Selection of the working fluids has a significant impact not only on the performance of the air conditioners but on the environment as well .Most refrigerant used for air conditioning contribute to global warming and many also deplete the ozone layer CFC, HCF  and HFCs ozone potent greenhouse gases when leaked to the atmosphere .

Heat Pump Unit:

                                  A heat pump is an air conditioner in which the refrigeration cycle can be reversed ,producing instead of cooling in the indoor environment .They are also commonly referred to as a reverse cycle condition .The heat pump is significantly more energy efficient then electric resistance heating. When the heat pump is  in heating mode the indoor evaporator coil switches roles and becomes the condenser coil, producing  heat. The outdoor condenser unit also switches roles to serves as the evaporator ,and discharges cold air.

Where the temperature is frequently in the range of 4—13 degree or 40—55 forehead

Evaporator Cooling:

                                          In very dry climates ,evaporator coolers ,sometime referred to as swamp coolers or desert coolers are popular for improving coolness during hot weather. An evaporator cooler is a device that draws  out site air though a wet pad, such air through a large sponge soaked with water. The sensible heat of the incoming air, as measured by a dry bulb thermometer is reduced

Evaporator coolers tend to feel as if they are not working during times of high humidity, when there is not much dry air with which the coolers can work to make the air as cool as possible for dwelling occupants .

Free Cooling:

                        Air Conditioning can also be provided by a process  called free cooling .Which uses pumps to circulate a coolant from a cold  source, which in turn acts a heat sink  for the energy that is removed from the  cooled space .

Humidity Control:

                                         Since humans perspire to provide natural cooling by the evaporation of perspiration from the skin drier air improves the comfort air  conditioner is designer to rate a 50%- to 60% relative humidity in the occupied space.

De humidification and cooling :

                                                                             Refrigeration air conditioning equipment usually reduces the absolute humidity of the air processed by the system .The relatively cold evaporator coil condenser water vapor from the processed air ,much like an ice cold drink will condense water on the system.

De humidification program:

                                                    Most modern air conditioning system feature a de humidification cycle during which the compressor runs while the fan is slowed as much as possible to reduce the evaporator temperature and therefore condenser more water .

Dehumidifier:

                           A specialized air conditioner that is used only for dehumidifying is called a dehumidifier.

Its also uses a refrigeration cycle but differs from a standard air conditioner in that both the    evaporator and the condenser .

Zamil Company Material :

                                                      Zamil Air Conditioners plant is a vertically integrated setup with in-house design and development facilities including a psychometric laboratory. Besides the air-conditioner’s assembly processes following manufacturing facilities are available:

Ø  Sheet Metal Shop with power presses ranging from 63 TON to 400 TON.

Ø  Heat Exchange Shops both for conventional copper tube heat exchange's and highly efficient cost effective MCHX (Micro Channel Heat Ex changer) Aluminum Coils.

Ø  Injection Molding Shop with capacity up to 1200 TON.

Ø  Tube Shop with in-house facility to manufacture copper tubing's.

Ø  Paint Shops for powder coating

·         ASQ Series

·         ASQ 045-440B

Ø  Air Cooled Screw Water Chillers with R-134a Available from 55 TR to 445 TR (194 KW – 1,565 KW)

Ø  AHRI certified performance

Ø  ALQ Series - ALQ 010-60C

Ø  ALQ Series

Ø  ALQ 010-60C.

Ø  Air Cooled Scroll Water Chillers with R407c

Designed for residential, medium sized buildings and light industrial applications

Designed to use the energy efficient and quiet hermetic scroll compressors

Designed to operate with R407c refrigerant up to 122 degree Fahrenheit  (50 degree Celsius ) ambient temperature.

Ø  Available from 10 TR to 60 TR (35 KW – 211 KW

Making the Parts:

                                       Most air conditioners are made from sheet steel or other easily formed metal or plastic. The first step in making an air conditioner is to form the metal and plastic parts. Metal parts are usually sheet stamped to give them the desired shape. Sheet stamping typically trims the metal to the required size. Large, flat plastic pieces are often vacuum formed, while smaller pieces are cast or formed using a number of different techniques, including vacuum forming. If the metal used is steel, it is then galvanized. Galvanization is the process of adding a layer of zinc to slow rust and other deterioration. Once galvanized, the steel is painted or powder coated. Powder coating is a durable form of paint that is sprayed on dry and then heated to melt and bond to the metal substrate.

Assembly:

                    Once the exterior parts are made, the air conditioner is ready for assembly. Most condensers, the devices that perform heat transfer functions, are pre-made. Most compressors, the device that compresses the gas that transfers the heat through the condensers, are also pre-built. Assembling the air conditioner is a matter of installing the compressor, the inside condenser, which cools the air being blown into the indoor area, the outside condenser, which transmits heat from inside the building to the outside air and  various electronic controls. The condensers are connected via copper pipes to the compressor, and the electronic controls are connected to an electric motor, which causes the compressor to spin.

Many air conditioners can even be installed by the owner, with ductless mini split systems a popular choice. Installation is still a major project, as the interior and exterior elements of the system need to be properly connected, but they are relatively inexpensive to buy and run.

Documentary Subject:  HVAC System:

                                The building automation device (computer or wall-mounted gadgets usually) can be used to determine whether to heat or cool the space, and to what temperature

The system then either heats or cools the coils inside

When air brought in from the outside is pushed through these coils, it is either heated or cooled before being pushed into the living space

At the same time, air will be displaced from the room back into the system.

Smaller air conditioning systems may operate in the reverse, however, where they collect heat from within a space and push it out in order to cool a room down. We can see these kinds of systems in places like cars. Here’s how these types of HVAC systems work:

v  Expansion

This device creates a restriction in the liquid line of a system, which in turn creates a pressure drop.

v  Evaporator

This device is what removes heat from the space by exchanging it for a boiling refrigerant.

v  Compressor

Think of this component as the system’s heartbeat - it creates the energy and thrust to move refrigerant around the system.

v  Condenser

This is the device that pushes the heat that has built up inside the refrigerant into the outside air.

v  Receiver drier

In order to preserve the air quality, this storage area for excess refrigerant contains a drying agent and a filter that removes contaminants from the system.

Documentary Subject:

 FIRE FIGHTING SYSTEMS:

                                                     A firefighting system is probably the most important of the building services, as its aim is to protect human life and property, strictly in that order. 

Ø  consists of three basic parts:

                                                     A large store of water in tanks, either underground or on top of the building, called fire storage tanks. A specialized  pumping system ,a large network of pipes ending in either hydrants or sprinklers (nearly all buildings require both of these systems)

A fire hydrant is a vertical steel pipe with an outlet, close to which two fire hoses are stored (A fire hydrant is called a standpipe in America). During a fire, firefighters will go to the outlet, break open the hoses, attach one to the outlet, and manually open it so that water rushes out of the nozzle of the hose. The quantity and speed of the water is so great that it can knock over the firefighter holding the hose if he is not standing in the correct way.  As soon as the fire fighter opens the hydrant, water will gush out, and sensors will detect a drop in pressure in the system. This drop in pressure will trigger the fire pumps to turn on and start pumping water at a tremendous flower

Ø  A sprinkler is a nozzle attached to a network of pipes, and installed just below the ceiling of a room. Every sprinkler has a small glass bulb with a liquid in it. This bulb normally blocks the flow of water. In a fire, the liquid in the bulb will become hot. It will then expand, and shatter the glass bulb, removing the obstacle and causing water to spray from the sprinkler. The main difference between a hydrant and a sprinkler is that a sprinkler will come on automatically in a fire. A fire hydrant has to be operated manually by trained firefighters - it cannot be operated by laymen. A sprinkler will usually be activated very quickly in a fire - possibly before the fire station has been informed of the fire - and therefore is very effective at putting out a fire in the early stages, before it grows into a large fire.  For this reason, a sprinkler system is considered very good at putting out fires before they spread and become unmanageable.  According to the NFPA of America, hotels with sprinklers suffered 78% less property damage from fire than hotels without in a study in the mid-1980s.

FIRE STORAGE TANKS:

The amount of water in the fire storage tanks is determined by the hazard level of the project under consideration.  Most building codes have at least three levels, namely, Light Hazard (such as schools, residential buildings and offices), Ordinary Hazard (such as most factories and warehouses), and High Hazard (places which store or use flammable materials like foam factories, aircraft hangars, paint factories, fireworks factories).   The relevant building code lists which type of structure falls in each category.  The quantity of water to be stored is usually given in hours of pumping capacity. In system with a capacity of one hour, the tanks are made large enough to supply the fire with water for a period of one hour when the fire pumps are switched on.  For example, building codes may require light hazard systems to have one hour’s capacity and high hazard 3 or 4 hours capacity. 

The water is usually stored in concrete underground tanks. It is essential to ensure that this store of water always remains full, so it must have no outlets apart from the ones that lead to the fire pumps. These tanks are separate from the tanks used to supply water to occupants, which are usually called domestic water tanks. Designers will also try and ensure that the water in the fire tanks does not get stagnant and develop algae, which could clog the pipes and pumps, rendering the system useless in a fire.

FIRE PUMPING SYSTEM:

                                                 Fire pumps are usually housed in a pump room very close to the fire tanks. The key thing is that the pumps should be located at a level just below the bottom of the fire tank, so that all the water in the tanks can flow into the pumps by gravity.

Like all important systems, there must be backup pumps in case the main pump fails. There is a main pump that is electric, a backup pump that is electric, and a second backup pump that is diesel-powered, in case the electricity fails, which is common. Each of these pumps is capable of pumping the required amount of water individually - they are identical in capacity.

There is also a fourth type of pump called a jockey pump. This is a small pump attached to the system that continually switches on to maintain the correct pressure in the distribution systems, which is normally 7 Kg/cm2 or 100 psi. If there is a small leakage somewhere in the system, the jockey pump will switch on

to compensate for it. Each jockey pump will also have a backup.

The pumps are controlled by pressure sensors. When a fire fighter opens a hydrant, or when a sprinkler comes on, water gushes out of the system and the pressure drops. The pressure sensors will detect this drop and switch the fire pumps on. But the only way to switch off a fire pump is for a fire fighter to do this manually in the pump room. This is an international code of practice that is designed to avoid the pumps switching off due to any malfunction in the control system.

The capacity of the pumps is decided by considering a number of factors, some of which are:

the area covered by hydrants / standpipes and sprinklers

the number of hydrants and sprinklers

the assumed area of operation of the sprinklers

the type and layout of the building.

THE DISTRIBUTION SYSTEM:

The distribution system consists of steel or galvanized steel pipes that are painted red.  These can be welded together to make secure joints, or attached with special clamps.  When running underground, they are wrapped with a special coating that prevents corrosion and protects the pipe.

There are basically two types of distribution systems

Automatic Wet systems are networks of pipes filled with water connected to the pumps and storage tanks, as described so far.

Automatic Dry systems are networks of pipes filled with pressurized air instead of water. When a fire fighter opens a hydrant, the pressurized air will first rush out. The pressure sensors in the pump room will detect a drop in pressure, and start the water pumps, which will pump water to the system, reaching the hydrant that the fire fighter is holding after a gap of some seconds. This is done wherever there is a risk of the fire pipes freezing if filled with water, which would make them useless in a fire.

Some building codes also allow manual distribution systems that are not connected to fire pumps and fire tanks. These systems have an inlet for fire engines to pump water into the system. Once the fire engines are pumping water into the distribution system, fire fighters can then open hydrants at the right locations and start to direct water to the fire. The inlet that allows water from the fire engine into the distribution system is called a slimes connection.

In high-rise buildings it is mandatory that each staircase have a wet riser, a vertical fire fighting pipe with a hydrant at every floor.  It is important that the distribution system be designed with a ring main, a primary loop that is connected to the pumps so that there are two routes for water to flow in case one side gets blocked.

In more complex and dangerous installations, high and medium velocity water-spray systems and foam systems (for hazardous chemicals) are used.  The foam acts like an insulating blanket over the top of a burning liquid, cutting off its oxygen.  Special areas such as server rooms, the contents of which would be damaged by water, use gas suppression systems.  In these an inert gas is pumped into the room to cut off the oxygen supply of the fire.

When you design a fire fighting system, remember the following:

Underground tanks: water must flow from the municipal supply first to the firefighting tanks and then to the domestic water tanks.  This is to prevent stagnation in the water.  The overflow from the firefighting to the domestic tanks must be at the top, so that the firefighting tanks remain full at all times.  Normally, the firefighting water should be segregated into two tanks, so that if one is cleaned there is some water in the other tank should a fire occur.

It is also possible to have a system in which the firefighting and the domestic water are in a common tank.  In this case, the outlets to the fire pumps are located at the bottom of the tank and the outlets to the domestic pumps must be located at a sufficient height from the tank floor to ensure that the full quantity of water required for freighting purposes is never drained away by the domestic pumps.  The connection between the two tanks is through the suction header, a large diameter pipe that connects the all the fire pumps in the pump room.  Therefore there is no need to provide any sleeve in the common wall between the two firefighting tanks.

The connection from each tank to the suction header should be placed in a sump; if the connection is placed say 300mm above the tank bottom without a sump, then a 300mm high pool of water will remain in the tank, meaning that the entire volume of the tank water will not be useable, to which the Fire Officer will object.

Ideally the bottom of the firefighting pump room should be about 1m below the bottom of the tank.  This arrangement ensures positive suction for the pumps, meaning that they will always have some water in them.

All pump rooms should without fail have an arrangement for floor drainage; pumps always leak.  The best way to do this is to slope the floor towards a sump, and install a de-watering pump if the water cannot flow out by gravity.

In cases where there is an extreme shortage of space, one may use submersible pumps for firefighting.  This will eliminate the need for a firefighting pump room.

Create a special shaft for wet risers next to each staircase.  About 800 x 1500 mm should suffice.  It is better to provide this on the main landing rather than the mid landing, as the hoses will reach further onto the floor.