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Sunday, May 27, 2018

SOLAR ENERGY SYSTEM



SOLAR ENERGY SYSTEM

Solar energy as renewable energy (RE)

Solar energy is renewable energy in which energy are generated from natural resources that can continually be replenished. It is clean, and it doesn’t contribute to global warming either through pollution or green gas omissions. Thus, it is environmental-safe. Not only that, RE gets significantly cheaper as time and technologies progress too.
Literally, solar energy is the radiation energy being produced by the sun.

Figure 1: Solar energy is the radiation energy from sun (Source: ZME Science)


Usage projection & current solar energy consumption

The International Energy Agency projected in 2014 that under its ‘high renewables’ scenario, by 2050, solar photovoltaic (PV) and concentrated solar power (CSP) would contribute to about 16% to 11% respectively of the worldwide electricity consumption. The following is the ranking of countries with their current solar energy consumption.
Ranking
Country
Installed PV [MW]
1
Germany
32,411
2
Italy
16,361
3
China
8,300
4
USA
7,777
5
Japan
6,914
6
Spain
5166
7
France
4,003
8
Belgium
2,650
9
Australia
2,650


Figure 2: Statistics shown by Renewable Energy Policy Network for 21st century (REN21) (Source: Renewables 2014 Global Status Report)

Advantages of solar energy

  • Renewable energy source: Among all the benefits of solar panels, the most important thing is that solar energy is a truly renewable energy source.
  • Reduce electricity bills: Since you will be meeting some of your energy needs with the electricity your solar system has generated, your energy bills will drop
  • Low maintenance cost: Solar energy systems generally don’t require a lot of maintenance. You only need to keep them relatively clean, so cleaning them a couple of times per year will do the job
  • Environment safety
  •  No noise and no moving part



Figure 3: Green solar energy save electricity (Source: Pixabay)

Disadvantages of solar energy

  •  Cost: The initial cost of purchasing a solar system is fairly high:
  • Large area needed to gain more energy: The more electricity you want to produce, the more solar panels you will need because you want to collect as much sunlight as possible
  • Solar energy storage is expensive: Solar energy has to be used right away, or it can be stored in large batteries. These batteries, used in off-the-grid solar systems, can be charged during the day so that the energy is used at night.
  • Weather dependent: Although solar energy can still be collected during cloudy and rainy days, the efficiency of the solar system drops. Solar panels are dependent on sunlight to effectively gather solar energy


Figure 4: Initial cost of installation is rather high (Source: Vector Stock)
Solar energy can be used in two ways: -
A. Passive solar:
Passive solar energy is the direct use of the heat and light energy absorbed for heating, lighting, drying, ventilation purposes etc. It is used in both architectural and urban planning by applying the green house concept, but also used in agriculture and horticulture, where techniques such as timed planting cycles, tailored row orientation, staggered row heights, mixing of plant vegetation, fruit walls, ad drying chicken manure are used.
      1. Direct gain:


Figure 5: Indirect gain passive solar system (Source: Tech-addict)
The presence of large and south facing exterior windows allows the sunlight to enter the building. In order to absorb radiation, thermal mass is used. The overhang also perfectly protects the large panel of window from higher angle summer sun but give access to lower angle winter sun, allowing it to absorb more heat during winter season. The sunlight is absorbed by the concrete flooring in the morning and the heat is reradiated back to the living space at night, providing warmth and next cutting down expenses required for HVAC system.
2. Indirect gain:


Figure 6: Passive indirect solar system (Source: Reseach Gate)
Collect and stories the solar energy in one part of the house (thermal mass) and use natural heat transfer to distribute heat to the rest of the house. The thermal mass most commonly used is the Trombe Wall which is a massive masonry that acts as the solar collector.
3. Attached Sunspaces:


Figure 7: Attached sunspaces passive solar system (Source: premies.com)
Uses a combination of direct and indirect-Gain systems that use water arums and a masonry floor as heat storage in the attached greenhouse. This conservatory can’t be overpopulated with vegetation as the foliage might cover and shade the floor or wall as heat absorber and collector.
B. Active solar:
Active solar convert the power from the sun and amplifies it using some special equipment. The solar panel is basically made up of the low iron tempered glass covers with a dark metal plates to absorb heat at the bottom of it, and also an insulated aluminium large flat box. It can provide 50 – 80% of household hot water required on a daily basis. The technologies used in generating electricity from active solar system include photovoltaic method (PV) and concentrated solar power (CSP).


Figure 8: Active solar using solar panel (Source: MIT Intiative)

1. Photovoltaic Cell (PV)
When sunlight strikes the surface of solar panel, the photons from the light hits the electrons in the negative plate (N- type semiconductor), where the energy is transferred from photons from the electrons. The electrons then flow to the equipment, and the flow of these electrons create current. The semiconductors that are commonly used are phosphorus, boron and silicon.


Figure 9: Photovoltaic cell (Source: Alternative Energy Tutorials)

2. Concentrated Solar Power (CSP)
Lenses or mirrors plus tracking system is used to focus a large area of sunlight into a small beam of transmitting the energy to the applications. It is contrary to PV in which PV converts light directly into electricity, but CSP makes use of the radiation energy from sun to generate electricity from the conventional steam driven turbine system. Technologies in tracking and focus sunlight include parabolic trough, compact linear Fresnel reflectors, parabolic dish and solar power tower.

Parabolic Trough
It consists of aa linear parabolic trough that concentrates the sunlight into a receiver filled with working fluid which is located on the reflector’s focal line. The working fluid then will pass to various heat exchanger and enter condenser to be discharged to turn the turbines, generating electricity. This system provides the best land-use factor of any of the solar technology.  


Figure 10: Parabolic Troughs (Source: Cleanleap)
Compact Linear Fresnel Reflectors
It uses many linear thin mirror strips to concentrate the sunlight into two tubes (linear absorber) with working fluid. The working fluid then undergoes the same process as the one in parabolic trough. This system is relatively cheaper, and a larger amount of reflectors can be placed in the same area of space, indirectly minimising the space consumed.


Figure 11: Compact linear Fresnel reflectors (Source: Shaikh Mohasin)
Parabolic Dish
It combines a parabolic concentrating dish with a Stirling engine which normally drives an electric generator. Stirling solar is of higher efficiency in converting sunlight into electricity. And also, it has a longer lifetime.


Figure 12: Parabolic sterling dish (Source: Department of Energy)
Solar Power Tower
It comprises a central receiver and a field of heliostats where the array of tracking reflectors (heliostats) will focusing the light onto the central receiver with air. The air then enter an air circuit and electricity generating system consisting of several steam generators and thermal storage and turbines. This is the most cost- effective technology among all, yet it offers higher efficiency. Better energy storage capability is achieved by this solar power tower too.

Figure 13: Heliostats type (Source: Alibaba)
NOT ALL ENERGY IS CONVERTED
However, not all energy strike on the surface is converted. Only when the photons hit the electrons, and the energy of the photons equals to that of the electron, absorption occurs.

THAT'S ALL FROM US ON SOLAR ENERGY SYSTEM! THIS WILL BE THE LAST TOPICS WE SHARED HERE! HOWEVER, HOPEFULLY THAT YOU'VE GAINED SOMETHING FROM US IN THESE 4 MONTHS!


Tuesday, May 22, 2018

LIGHTNING PROTECTION SYSTEM

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Lightning Protection System


A lightning protection system typically includes a rooftop network of electrical conductors, multiple conductive paths from the roof to the ground earthing, bonding connections to metallic objects within the structure and a grounding network.

        Lightning protection systems are installed on structures, trees, monuments, bridges or water vessels to protect from lightning damage. Individual lightning rods are sometimes called finials, air terminals or strike termination devices.

(Sources: Pinterest)

Conventional Lightning Protection System Installation

External & Internal Lightning Protection System (LPS)

Function of an external lightning protection system
· Interception of direct lightning strikes via air-termination system
· Safe discharge of lightning current to earth via down-conductor system
· Distribution of the lightning current in the ground via an earth-termination system

Function of an internal lightning protection system
· Prevention of dangerous sparkling in the structure by establishing equipotential bonding or keeping a separation distance between the LPS components and other electrically conducting elements

Component of lightning protection system 

Air Termination System

Lightning rod is a metal rod mounted on a structure and intended to protect the structure from a lightning strike.In lightning protection system, lightning protection rods are placed at regular intervals on the highest portions of a structure.

If lightning hits the structure, it will preferentially strike the rod and be conducted to ground through a wire instead of passing through the structure, where it could start a fire or cause electrocution.

(Sources: Chairish)

Made up of vertical air terminals and / or a lattice of copper conductors on the roof and edges of the structure. Since no part of the roof should be more than 5m from the nearest horizontal earthing conductor.
Traditional taper-pointed air terminals are not as frequently used today but when they are they should be positioned near those points where a strike is most likely to hit the building.

 (Source:google.com)


(Source:google.com)

The system is acceptable, provided an imaginary sphere never intersects the surface of the structure to be protected without settling on the components of the air termination. In principle, the mesh size determines that any point on the roof is nearer to the air termination network than half the side of a mesh.
The Hungarian Standard for Lightning Protection of Structures specifies the degree of the air termination systems according to combinations of several classifications, namely, the class according to function of structure, the class according to height and surroundings, and the class according to materials of the roof.

Down-conductor Termination System 

Down conductor is a material which contains movable electric charges. In a lightning protection system, the conductor connecting the air terminal or overhead ground wire to the earth electrode subsystem for making a discharge path.
(Sources: DIGTY CREW)



(Sources:google.com)

The purpose of the down conductor is to provide the low impedance path from the air termination system to the earth system. There is typically one down conductor for every 20m or part thereof the building perimeter at roof or ground level. If the building is above 20m in height or of an abnormal risk this distance should be reduced to 10m. Any good conductor which forms part of the building structure can be employed as a down conductor with appropriate connection to the air termination and earthing systems. For down leads not part of the structure, copper earth tapes and aluminium earth tapes are the most widely used materials.


Earthing system defines the electrical potential of the conductors relative to that of the Earth's conductive surface. Lightning protection systems are special grounding systems designed to safely conduct the extremely high voltage currents associated with lightning strikes. In an electrical installation an earthing system or grounding system connects specific parts of that installation with the Earth's conductive surface for safety and functional purposes. The point of reference is the Earth's conductive surface.


Earth-conductor Termination System

  (Source:google.com)

Each down conductor, or copper earth tape,  must have its own earth electrode termination and the resistance to earth of the whole system must not be greater than 10 Ohms without taking into account bonding to other services. The most common terminations are copper earth rods driven into the ground. These should be a minimum of 9 metre for the whole system.The individual earth electrodes are sometimes interconnected by a ‘ring conductor’ to help reduce the overall resistance. This should be at least 0.6m below ground level and preferably pass below incoming services. The ring conductor is made from copper tape or cable (aluminium is not permitted for use below ground) and also helps to provide potential equalisation at ground level, in addition to potential grading.The earth system should be designed as a whole since the complete installation should rise in potential together, to avoid excessive voltage differences. For this reason, the earth termination should be bonded to the rest of the earth electrodes.                                                                                                                 





(Sources:google.com) 




(Sources: Electrical technology)
        Earthing system


(Sources: IndiaMART)
Earthing rod


   Example on failure of ESE air terminals in Malaysia


(Sources: www.ground.co.kr)

(Sources: www.ground.co.kr)


(Sources: www.ground.co.kr)


(Sources: www.ground.co.kr)


(Sources: www.ground.co.kr)



    Damages by lightning (Lightning injuries)

 Fire Damage

The biggest threat lightning poses to a structure is fire. Wood and other flammable construction materials can easily explode when exposed to the high temperature of a lightning strike. Lightning current travelling through wires and pipelines instantly burns them up causing complete damage to property.

Health Effects

Lightning current which flowing through the victim's body resistance may develop a high voltage sufficient to flash around the skin or clothing to the ground in a direct strike, resulting in a surprisingly benign outcome. Besides, lightning may also effects on skin burns while the intense electric current can cause a loss of consciousness; it is also speculated that the EMP created by a nearby lightning strike can cause cardiac arrest.

Destruction of Electrical Equipment

Lightning is the biggest cause of damage of electrical equipment in industrial facilities, commercial buildings and homes. The bolt of lightning found its way down the mains cable and destroyed / burnt out what were a distribution boards within a school where we carry out regular work.

While the exact cause of lightning is still uncertain, scientists know it happens when clouds filled with water and ice rise rapidly. It is thought the heat causes the clouds to soar creating a lightning strike.

Source: Google image

Surges – underestimated risk.

The function of a lightning protection system is to protect structures from fire or mechanical destruction and to prevent that persons in buildings are injured or even killed. An overall lightning protection system consists of external lightning (lightning protection/earthing) and internal lightning protection (surge protection).                                   

NEXT WEEK WILL BE OUR LAST SHARING ON SOLAR ENERGY SYSTEM! STAY TUNED AND SEE YOU! THANK YOU :)


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Friday, May 18, 2018

GAS SUPPLY SYSTEM

 GAS SUPPLY SYSTEM

The Gas Supply Act 1993 (Act 501) and Gas Supply Regulations have been enforced since 17 July 1997. With these legislations in force, all activities pertaining to the supply of hydrocarbon gas through pipelines, its supply to consumers and use will be regulated by the Regulatory Agency. The purpose of such legislations is to ensure that the interests of all stakeholders, i.e. the gas supply industry, consumers and public on safety, economy, reliability, quality and efficiency aspects are taken care of. In principle, the Gas Supply Act applies to gas supply activities to consumers through pipelines as follows:
- Downstream of the last flange of the city gate station.
- From the storage tank or cylinder specifically used for reticulation of gas any apparatus in any premises.
Figure: Typical gas supply system in Malaysia (Source: Castleteamservices)

Types of gas supplied to consumers


It is a fossil fuel that contains primarily methane, along with small amounts of ethane, butane, pentane, and propane. Like other fossil fuel such as coal and oil, natural gas from the plants, animals and microorganisms that lived millions of years ago.

  • Natural gas (NG)
  • Natural Gas Liquid (NGL)
  • Liquid Petroleum Gas (LPG)
  • Liquid Natural Gas (LNG)


Figure: Formation of petroleum and natural gas (Source: Google Image)

1. NATURAL GAS (NG)

Characteristics.

Natural gas does not contain carbon monoxide. The by-products of burning natural gas are primarily carbon dioxide and water vapor. Natural gas is a colorless, tasteless, odorless and non-toxic gas.
  • Can solve hard problems reliably
  • Easy to interface with existing models
  • Easy to hybridize with other methods
  • Extendible
  • Need very little domain knowledge

Figure: Physical properties of natural gas (Source: Google image)

Uses.
Natural gas is a fossil fuel used as a source of energy for heating, cooking and electricity generation. Its is also used as a fuel for vehicles and as a chemical feedstock in the manufacture of plastics and other commercially important organic chemicals. Water heating accounts for the second larges use of energy. A natural gas water heater is one of the most economical fuel systems available. Once your home is connected to natural gas, it is easy to add appliances such as ranges, cook tops, dryers, fireplaces or outdoor grills. 



Figure: Uses of natural gas on a regular basis (Source: Google Image)


Figure: Percentage of natural gas used in daily life (Source: Google Image)


Types of natural gas components.
Natural gas is primarily composed of methane, but also contains ethane, propane and heavier hydrocarbons. It is also contains small amounts of nitrogen, carbon dioxide, hydrogen sulphide and trace amounts of water.

Figure: Typical Composition of Natural Gas (Source: Google Image)

Figure: Natural gas industry (Source: Google Image)

The main content of natural gas is methane with small percentages of ethane. LPG comprises propane and butane. Natural gas will go trogh the various stages of processing to produce liquefied natural gas. Gas from offshore will transfers through subsea pipelines to the gas station will be measured. Next, the gas is channel to the drying unit in which bubbles of steam will be removed. The remaining gas will be delivered to cooling it to a temperature of -161 celcius by using coolant. 


Equipment of gas.
Natural gas brings comfort and convenience to your home, while reducing your environmental footprint.

Gas supply system is equipped with :
  1. Gas pressure meter
  2. Communication system
  3. Warning system
  4. Automatic Control System
  5. Stop valve equipment to disconnect a pipe or even a separate section of the building during emergency and repair work.
  6. Gas distribution and gas service line.
  7. Its role is to deliver gas from the distribution point of the municipality and stations and from the gas storage facilities to user.

  • Furnaces and heating - The great quality air of your home's heating system can directly impact how comfortable you and your family in your home.
  • Water heaters - Have peace mind. Enjoy plenty of hot water. Lower your energy bills. You get all that with a high-efficiency natural gas water heater.
  • Fireplaces - Flip a switch and set the mood with a relaxing fire. 
   Figure: Water heater typically used at home (Source: Google Image)


Figure: Furnace at home (Source: Google Image)

Figure: Connection of a home heating system (Source: Google Image)

Method of installation gas systems.

Make connection to steel gas pipe.
Remember, you can't connect the flare fitting on the flexible gas line directly to a steel pipe thread. You have to install the flare fitting that's included with the kit.


Connection to soft copper.
Common sizes of flare fittings are 3/8 inch, 1/2 inch and 5/8 inch. Match the flare fittings to the outside diameter of the soft cooper you're connecting to. 


Figure : Connection to soft copper (Source: Google Image)

OUTSIDE INSTALLATION
Whenever the pipe is installed outside where it can be exposed to direct sunlight, it shall be covered to prevent continuous exposure.

INSIDE INSTALLATION 
Whenever the pipe is installed inside the building, it can be installed exposured to indoor light or it can also be embedded in concrete, or behind the wall in dry wall systems as needed.

UNDERGROUND INSTALLATION
Make sure the types of pipe or the materials of pipe is resistant against acid, alkaline or salty soil and allows the system to be buried underground.

GENERAL
It can be installed behind drywall and above false ceiling or surface mounted, as long as it encased with some protection likes concrete, steel or resistance chemicals and corrosive activity.

2. LIQUEFIED PETROLEUM GAS (LPG)

LPG is a mixture of propane (30%-40%) and butane (60%-70%). LPG is stored as liquid under pressure is colourless and odourless in its natural state. LPG vapour is heavier than air. Therefore, the vapour may flow along the ground and into the drains and ignited at a considerable distance from the source of leakage. LPG forms a flammable mixture when mixed with air within the flammability limit to large volumes of vapour/ air mixture and thus cause considerable hazard. LPG is odouless before distribution, such tat any escape of has may be noticable by its smell.

SO TODAY'S SHARING IS A BRIEF INTRODUCTION ON GAS SUPPLY SYSTEM IN BUILDINGS! LOOK FORWARD TO NEXT WEEK SHARING TOPICS ON THE LIGHTNING PROTECTION SYSTEM!

Source: Live Science