Fire Tube Boilers Water Tube Boilers

Published Date: 02 Nov 2017

Fire tube boilers have a series of straight tubes which are situated inside an outer shell filled with water.

Water tube boilers have diversely bent and complex tubes which are extended between an upper head namely streams drum and lower heads.

The hot combustion gases flow via the tubes heating the water around the tube.

Hot combustion gases are circulated around and outside of the tubes filled with water.

Suitable for low pressure steam because at high pressure the thickness of the tube increases if an external pressure is applied. With the same tube thickness, the pressure in a water tube boiler can be twice that of a fire tube boiler.

Ideal for high ( above 500 psig) steam pressure and high temperature upto 1000 F and has large capacity exceeding millions of lb/h of steam.

Suitable for high pressures as gas is contained inside tubes.Hence you see more of them in hydrogen,ammonia plants,where the gas pressures can be in the range of 500 to 3000 psig.

Extended surfaces can be used in waste heat applications to make the boilers compact if the gas stream is clean

2

Electricity

Solar

Fossil fuels (petroleum, LP gas, Diesel, Kerosene and Coal)

Wind

Agricultural biomass

Chemical Batteries

Bio gas

Combustibles, fire wood

The transferring to electrical energy is a convenient process.

Also the distribution and production process are convenient when compared with other energy sources.

It is versatile and controllable.

Electricity is clean energy source as it does not give any residue after usage.

Electricity is convenient to use

It is a cheaper source of energy

It is a safer source of energy

And it is a reliable source of energy.

The non renewable energy sources produce a large amount of carbon dioxide and other pollutants to the environment. These increased impurities have lead to the global warming.

This problem can be overcome by replacing these energy sources with alternative energy sources. The alternative energy are considered as free sources and are renewable, and emit less carbon dioxide comparatively. These include,

Biomass

Wind energy

Solar energy

Geothermal energy

Hydro electric energy

Solar Energy

The sun emits light and heat energy of 174,423,000,000,000 kilowatt hours to the earth per hour. This large amount of energy is sufficient to fulfill the needs of the entire global population, and also to supply light and heat energy for the growth and living of fauna and flora too.

Solar energy can be used for space and water heating in buildings.

Electricity can be generated from solar energy through solar electric cells namely photo voltaic cells. These cells can convert light energy into electrical energy which could be used for lighting, powering equipments or to charge storage batteries etc. the maintenance is easier and the running cost is quite low.

Solar panels or solar connectors can be used to obtain solar thermal to heat water using direct sunlight. The water circulating through the solar panels or collectors get heated and can be stored in tanks. There are various types of solar thermal systems which could provide hot water for domestic, commercial or industrial use. And the temperature of the water depends on the amount of sunlight and water could be warmed even in cloudy conditions.

We can also use parabolic mirrors where the sun rays hit to heat water.

And the windows or window blinds could be simply opened in order to allow natural sunlight to enter and heat a room.

Solar power can also be used to desalinization of water.

Some of the advantages of using solar energy are,

It’s a renewable resource and will newer diminish.

Since there are no chemical reactions taking place, it causes no pollution to water or air.

Can be used very efficiently for purposes like heating and lighting.

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Wind Power

Wind power can be used to operate machineries like flour mills, and wind turbine systems on small buildings can be used to collect large turbines in wind farms on sea and land. The wind farms can generate electricity.

Wind power can be used to pump water and grind grain as used by ancient Persians.

Wind energy is available and Pollution free.

But the installation cost is high, and the turbines cannot be installed easily. And even the maintaining cost could be quite high.

A Large number of wind generators are required to produce wind energy; therefore a big amount of space is required to produce heat or electricity.

And wind turbines cannot be put up at any place but only in a suitable windy place and there should be adequate land space for installation.

Geo thermal Energy

Geo thermal energy is obtained from the heat of the earth by radioactive decay. It is found to be a clean and sustainable source of energy. The resources are obtained from the low ground to hot water and hot rock available a few miles below the earth surface and also deep down a molten rock namely magma with extremely high temperature. Nearly everywhere the low ground or upper ten feet of the surface of the earth an almost constant temperature between 50° and 60°F (10° and 16°C) is maintained.

Geo thermal energy can be used for bathing in hot water, space heating, electricity generation, desalination, agricultural activities and industrial applications.

This is reliable, sustainable and economical and environmental friendly. But geo thermal wells do give out green house gases, not as much as fossil fuels though. It gives out a low amount.

The digging and exploration processes are very costly.

For heating and cooling of buildings a geo thermal heat pump can tap the resource. The heat pump contains a heat pump, duct work, and a heat exchanger. The heat pump can remove heat from the heat exchanger in winter and pump it into an indoor air delivery system. And during summer it could do the vice versa, the heat is moved from the indoor air to the heat exchanger. The removed heat from the indoor air can also be used to heat the water for a hot water supply.

For generating electricity, wells can be dug into underground reservoirs. The steam from a reservoir can be used to power a turbine or a generator in a geothermal power plant. Directly, for heating purposes, the hot water near the surface of the earth can be used. The heating applications can be heating of buildings, drying of crops, in green houses, at fish farms to heat water, and any other industrial applications like pasteurizing milk etc.

Biomass

Biomass is organic matter produced due to the photosynthesis of light. Organic matter can be plants, biological materials form living things or plant derived materials. Th eorganic matters are stored and then made to produce energy. The energy conversion in biomass can be done by thermal conversion, biochemical conversion or chemical conversion. Human have used biomass even in history to derive energy when they used wood to produce fire.

Nowadays, biomass can be used to generate electricity through steam turbines or gasifiers. And also can be used to produce heat by direct combustion. The energy derived from biomass gives out less carbon dioxide, but it does not release new carbon to the environment which makes it safer than burning fossil fuels.

Wood is one of the biggest biomass energy ources nowadays. For example the residues from forest, dead trees, stumps, and also solid waste can be used to produce biomass energy.

Biomass can convert organic matters into fibres or some other industrial chemicals such as bio fuel. Plant Energy can be produced by specific crops which are grown with the sole purpose to give high output of energy. For example, wheat, where the straw can be burned in order to produce heat or energy and the grain can be used as a liquid fuel for transportation. Plant biomass can undergo degradation through a series of chemical treatments from cellulose to glucose, and the final glucose can be used as a first generation bio fuel. By rottening of agricultural waste, human waste and garbage, methane can be obtained. Fermentation of crops like corn and sugar cane can produce ethanol which is a transportation fuel. From left over food items such as vegetable oils and animal fats, another transportation fuel bio diesel can be produced.

Hydro Electric energy

Hydro electricity is the electricity generated by hydro (water) power by letting the water flow or fall with effect of gravitational force. The cost of production is comparatively quite low, and has a lesser output of greenhouse gases and produces no direct waste.

d)

03)

a)

CENTRAL AIR CONDITIONING

SYSTEMS

UNITARY AIR CONDITIONING SYSTEMS

Operating and maintenance work could be done without hindrances to the occupants or work as it’s normally located in unoccupied separate space.

Operating and maintenance could be hindrances as it’s located within the working or occupied premises.

Needs a huge space

Does not need a huge space

No noise because it is placed away from the occupied space

Gives out noise as its located within the occupied premises

A lot of pre planning is required before installation as the process is quite complicated. Have to get the concern of architects, mechanical and structural engineers

No need of pre planning as the installation process is quite easy. Not necessary to get the concern of engineers.

Air balancing is difficult.

No difficulty in air balancing

b)

i)

Window air Conditioner

Split air conditioner

Central air conditioner

ii)

04)

THREE PHASE INSTALLATION

Three phase power can be used when we need more power like in industrial and commercial application as some electrical equipments ( like air conditioners, motors and pumps, UPS systems, Bulky machineries etc ) consume a large current. Normally a three phase power is not transmitted to domestic houses. But if it is, it’s split at the main distribution board.

This is an electrical supply for huge electrical installation and transmitted by the national grid system. This system uses a less conducting material in order to transfer electricity than single, double phase or direct current systems at the equal voltage.

Three alternative currents having the same frequency and which reach their instantaneous peak values at varying times are carried by three circuit conductors. The three phase system can sometimes have a neutral wire and sometimes not. If there’s a neutral wire, the system can use high voltage at the same time can support low voltage single phase appliances as well.

3-phase.jpg

Mechanical energy is converted into a group of alternating electrical current by electromagnetic coil or by winding a generator at the power station. All the currents are of the same frequency but the time is differed to give varying phases and the currents have sinusoidal functions of time. The phases are equally spaced and give one third of a cycle separation.

Transformers change the output voltage of generators at the power station to a suitable level to transmit in order to reduce losses. After converting voltage several times in the transmission network the voltage eventually transformed for standard use before supplying to customers.

Transformer

Between the phases of a three phase supply, a delta connected transformer is connected.

COLD WATER SUPPLY

Cold water supply system is the general water supply used in building for washing, cleaning, cooking and any other functions in industrial and commercial buildings. Cold water supply can be fulfilled by,

Municipal or water board

Delivery trucks

Private sources such as rivers, wells, streams etc

Desalinated water

Processed water from rivers, streams etc

Recycled water

Most commonly the water is directly supplied from a municipal water system using a high pressure pipe which is normally situated below the road or streets. Most of the dwellings fulfill their requirements by wells, in which a pump or a pressure tanks are used to produce and maintain system pressure necessary to supply water.

The water suppplied should be clean, colourless, without any harmful bacterias or suspended matter, taste good, and moderately hard.

The main distribution, water board fully treats the water before supplying to domestic homes and partially treats and usually chlorinates the water before supplying to industries. And very large industrial buildings fulfill their water requirements by their own supply by treating them for their requirements.

Mains water to building can be divided in to the following catergories,

Trunk mains

These transmit water from a water resource like reservoir, pumping stations etc, to a place without delivering to consumers on the way.

Secondary mains

The distribution mains, which are fed by the trunk mains supplies consumers in the place.

Service Pipes

These are branched and supplies to induvidual premises from the secondary mains.

Prominenece should be given to avoid any inter connection or cross connection of the supply lines with other waste water supply lines to prevent from contamination. The water service should designed to avoid bachflow or back siphonage into the supply system via any openings.

Main Connections

The trunks or secondary mains are usually connected to pipes by the water board. Its not appropriate to connect a service pipe directly to a trunk main. Connections of pipes with diameter 50 mm and less to the secondary mains can be made under pressure , but a shutdown of the mains is needed for bigger pipes. Supply pipes will be fixed by the main water board from the main until the border of the area to be supplied. At this point to isolate the areas water system with the main a stop valve is connected. For the purpose of charging from the consumers a water meter is fixed.

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In order to prevent from damages to the service pipes due to heavy vehicles, the pipes must be kept a minimum depth of around 760 mm.A valve pit with key operate lid can be installed in a situation of emergency isolation to access easily and usually situated in footpaths .

The following diagram shows the entering of mains water supply into a building. For the movement of the pipe and settlement of the building , the pipe is sleeved.401.gif

In order to have a water supply through out 24 hours, even when the water service has been cut, installation of a storage tank is necessary. The cold water consumption depends on,

The purpose of use

The number of consumers

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In houses, fro small scale installation plastic or Glass reinforced plastic tanks can be used. These reduce the leakage as they are manufactured as one piece item. For big scale installation, glass reinforces plastics or galvanized steel panel tanks are used.

There shouldn’t be any stagnant regions, also inlets and outlets should be placed at opposite ends to make sure a through water flow.

Inlets and outlets should be at the same level and pipe lengths to maintain a balanced flow of water. Every tank should have its own ball valve, overflow discharge pipes and float arrangement for ball valves. The valve drain is used fro the purposed of cleaning the tanks often to avoid grime building up and remove dust. A delayed action float valve is used to make sure a higher turn over of water.

The cold water temperature could be up to 25 C, but its better to maintain the temperature less than 20°C to avoid the growth of micro organisms. This can be done by insulating the tanks, fittings, pipe works and also the valves. This will also reduce condensation. The water lines should not pass close to hot water lines or other heat sources such as radiators or boilers.

If the height of water in the main is not enough to provide water to the upper floors in a high rise construction, the water needed should be pumped up the building. For this purpose a pressure boosting equipment should be installed. There are three types as follows

Pneumatic system – basically pressure is controlled here

Intermittent pump – basically controlled by float switch

Continuously running pump – quite useful for small systems and runs on pump characteristics and a tiny pressure bleed from delivery to suction.

Fixtures and appliances in a cold water system

Hose bibs or taps

Storage tanks

Valves

Water closets

Urinals and bidets

Sinks, basins

Bath tubs and showers

Drinking fountains

 

 

 

06)

a)

Advantages

The transferring to electrical energy is a convenient process.

The distribution and production process are convenient when compared with other energy sources.

It is versatile and controllable.

Electricity is clean energy source as it does not give any residue after usage.

Electricity is convenient to use

It is a cheaper source of energy

It is a safer source of energy

And it is a reliable source of energy.

Disadvantages

Electricity could be harmful if not carefully used or if there is any leakage. Can even cause death due to high electric shock.

Currently in Sri Lanka and also the world, the demand for electricity has increased and has to be quite careful while using without any wastage to conserve energy.

To make a resistance free path in power lines a large amount of energy even more than the amount used to produce it is needed.

There is no way of storing the extra electricity that is not used.

Electricity is useful but at the same time can be harmful. Therefore certain safety ddevices are installed in order to provide protection against electric shock, over current, and isolation and switching. The devices are as follows,

Switch gear

Factors to be considered when choosing and installing a Standby Generator

Availability of space to store the generator

Power requirement in the place where the generator is going to be installed

Dimension of the generator

Choose whether you want a air cooled or liquid cooled standby generator depending on the power requirement. Liquid cool systems give more power.

Type of fuel used in the generator (natural gas or propane)

Installation and purchasing cost

Amount of noise given out

Obtain permit from relevant authorities before installation

Needs professional help for installation

Install a transfer switch, which will close all the utility power lines in the electrical system off safely and opens a direct line to the generator and does the reverse when the house power supply is restored.

Whether the transfer switch is automatic or manual

Go through local building codes before installation

The generator should be placed on top of a concrete slab or plastic mounting pads.

Seek the help of a contractor to mount the generator

Contact the gas or propane company to properly fix the generator to the energy source.

Get the help of an electrician to fix the unit to the electrical supply

Electrical intallation includes the blend of electrical equipments in order to accomplish a specfic purpose and pocess coordinated characteristics. While installation and usage, one should be very careful to avoid any harms that could be caused to human as well as the equipments.

In the building under study, there are around ……. Students visiting the place, and around …….. staff working including the lecturers, office staff and the maintenance staff.

The basement of the building contains the car park and a canteen. In the ground floor the administrative offices are located. And then onward there are three more floors where the lecture halls are located.

As this is an institute with gathering of whole lot of students, it is very important to manage the transportation of goods and people within the building. There could be a large number of students moving around the building or up and down the building at the same time. Normally during the morning hours and the afternoon hours that is before the lectures start you can see a high congestion in the building due to the accumulation of students all over the building. In this case care should be taken to move the people without bumping into each other, or causing delays to attend lecture due to congestion, or any other uncomfortable things that could occur due to overcrowding. And special preference should be given to vertical transportation as more risks of injuries are associated with this if a proper vertical transportation provisions are not available not available.

And when it comes to good, there is no much instances of transporting goods round the building especially up and down the building. But in the basement, where the canteen is located, there’s a need to transport goods, that is provisions.

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