1. KRISHNA BEACHRESORT, PALLIYAMMOOLA.
A Technical Report on
DaikinVRV- IV A/c system & Renewable Energy System
November 2015 – October 2016
Divya.K.V
B.Tech EEE
Electrical Engineering Trainee
Krishna Beach Resort,
Palliyammoola,
P.O. Alavil,
Kannur- 670 008

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Contents
1. Krishna Beach Resort : 03
2. Air conditioning system : 04
3. Sewage Treatment Plant : 10
4. Water TreatmentPlant : 13
5. Waste Management : 15
Bio gas plant : 15
Incinerator : 17
6. Fire fighting measures : 21
7. Security : 26

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Krishna Beach Resort
Krishna beach resort, a holistic resort for body, mind and soul is one of the
prestigious project of Krishna Jewels, Kannur is situated in Palliyamoola, near
Payyambalam. Which is hardly 5Km from Kannur Town. Main attraction of the resort is its
architectural beauty with laterite stones. Our lobby is designed with a unique architecture
symbolizing different chakras in a human body. It consists of a dome that provides natural
daylight.
There is a separate waiting lounge for the guests with sculptures of prophets and
philosophers. There are 3 restaurants located on different floors. The coffee shop is located
at the ground floor level. It provides buffet choice with a total number of 50 covers. It
provides a variety of dining options from sandwiches to Kerala Delicacies. The fine dining
Specialty restaurant is located at first floor with a total of 50 covers and serves delectable
continental cuisine. To promote our Local cuisines, we have Kerala buffets located in the 3rd
floor with a total 50 cover. There is an exclusive art gallery showroom that showcase local
arts, handicrafts, antique items etc.
The resort is equipped with a banquet hall located at first floor that can host a
reception up to 600 guests. There are 2 family get together rooms that cater to the needs of
an informal gathering up to 50 guests. The premise also includes an open air roof top
banquet, which has a room for 500 guests. The open air space gives a breathtaking
backdrop of the Krishna Beach horizon.
A business center is located behind the reception where the guest can avail the
facilities like printing, faxing, internet, Xerox, etc. The space for Health club, spa and fitness
center has been allotted in a separate building outside the main block. There is a separate
space allotted to the parking area for the guest with a specific driveway of 4m wide where a
total number of 100 cars can be parked. One of the remarkable feature of the hotel is the
Open theatre with the splendid view of Shiva’s statue which has a seating capacity of 1000 .

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A separate room has been designated only for the differently abled guest located at
ground floor and situated just aside reception and is designed with features for easy
accessibility of a differently abled guest The facilities include a door that allow wheelchair
access, low height furnitures, low peep hole, cupboard having sliding doors with low clothe
hangers, audible and visible alarm system. A separate parking space is allotted for the
differently abled guest that is nearest to the main building of the hotel block.Ramps are
built at the entrance to the lobby and to the room. The lift is situated just right across the
corridor where he can gain access to the Continental restaurant on the first floor. A unisex
Toilet for physically handicapped is being provided at the ground floor lobby level. The size
of the toilet is 52 sqft and consists of hand rail (@1mtr height) and other special features
and amenities that would cater to the needs of a differently abled guest.
1. AIR CONDITIONINGSYSTEM – DAIKIN VRV IV
Daikin’s VRV IV systems integrate advanced technology to
provide comfort control with maximum energy efficiency and
reliabilty. Currently available in heat pump and heat recovery
configurations,VRV IV provides a solution for multi-family
residential to large commercial applications desiring heating or
cooling. The VRV IV is the first variable refrigerant flow (VRF)
system to be assembled in North America.
1.1. What’s new about VRV IV?
1. Optimized Installation with New Unit Ranges for low
total Life Cycle Cost (LCC)
Larger capacity single modules now range up to 14 tons.
Modules can be combined to provide up to 34 tons from
three modules on a single piping network, saving
installation cost by reducing piping and electrical
VRV OUTDOOR UNIT

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connections. Plus, system components allow flexibility to
handle future building changes while minimizing retrofit
requirements.
2. Energy Efficiency with Variable Refrigerant
Temperature (VRT)
VRV IV’s revolutionary Variable Refrigerant Temperature
control automatically adapts to the unique requirements
of your building and climate, significantly reducing
seasonal operational cost compared to VRV III. Customize
your operation between Automatic Mode, High Sensible
Mode or Basic Mode to suit the application’s needs. >See
more about VRT
3. Fast Installs mean Fast Commissions
VRV IV’s new commissioning tool enables designers to optimize system configurations
to take advantage of new system capabilities, as well as new products from Daikin. This
allows actual system settings to be optimized for comfort and energy savings from
installation, reducing commissioning time.
4. Ensure Peace of Mind with a Limited 10-Year Warranty*
VRV IV is the first Daikin VRV to be assembled in North America. A best-in-class
warranty* with 10-year compressor and parts limited warranty as standard ensures
our confidence in our new VRV IV.
1.2. Overviewof VRV IV Features.
 Total comfort solution for heating, cooling, ventilation and controls
 Redesigned and optimized for total Life Cycle Cost (LCC)
 Reduced install cost and increased flexibility as compared to VRV III with larger
capacity single modules up to 14 tons and system capacity up to 34 tons

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 Efficiency improved over VRV III by an average of 11% with IEER Values now up to
28
 Improved seasonal efficiency as compared to VRV III with automatic and
customizable Variable Refrigerant Temperature (VRT) climate tuning
 Best-In-class warranty* with 10-year compressor and parts limited warranty as
standard
 Reduced commissioning time vs. VRV III with VRV configurator software and
Graphical User Interface (GUI)
 Design flexibility with long piping lengths up to 3,280 ft. total and 100 ft. vertical
separation between indoor units
 Take advantage of Daikin’s unique zone and centralized controls
1.3. TECHNOLOGY
Daikin’s VRV IV systems integrate advanced technology to provide comfort control with
maximum energy efficiency and reliability. Currently available in heat pump and heat
recovery configurations, VRV IV provides a solution for multi-family residential to large
commercial applications desiring heating or cooling. The VRV IV is the first variable
refrigerant flow (VRF) system to be be assembled in North America.

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Variable Refrigerant Temperature
VRV – Constantly Evolving, Setting the Standard.
VRV IV combines a number of substantial improvements in system capability and function
compared to VRV III.
Larger capacity units now utilize new inverter compressors for all configurations. This
improves overall efficiency and allows the VRV IV to start with essentially no inrush power.
This is ideal for limiting demand expense and for solar installations or facilities that may
occasionally run on generator power, where a high amperage starting requirement is
difficult to meet.

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VRV IV now uses a four-sided coil that presents a greater heat exchange surface. While
allowing the same footprint for all unit sizes for ease of design, we have increased
efficiency through improved heat transfer on all sizes. This change has also enabled
increasing capacity in our standard modules, extending the range up to 34 tons on a single
network. Many applications have been simplified, as fewer units can be used to achieve
desired performance. Another added benefit to this is a reduction in system refrigerant
volume.

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1.4. FEATURES
Flexibility is everything
 Large capacity range (6 – 34 ton), up to 64 indoor fan coil units on one system and
up to 200% connection ratio
 Long piping length, up to 3,280’ total, with up to 100’ vertical separation
 Wide range of indoor units, including additional “mini-split” units
 Redesigned and optimized for low total Life Cycle Cost (LCC)
 All inverter compressors in all model sizes
 New configuration software allows full setup offsite with PC upload
 10-year limited warranty* on compressor and parts is standard
* Complete warranty details available from your local dealer or at www.daikincomfort.com.
To receive the 10-year compressor and parts limited warranty, online registration must be
completed within 60 days of installation. Online registration is not required in California or
Quebec.
Environment
 Efficient overall system performance, up to 28 IEER
 Excellent heating performance, up to 4.20 COP
 Variable Refrigerant Temperature control cycle provides improved seasonal
efficiency
 Quieter than VRV III
 Improved refrigerant leakage control
 Reduced factory charge (refrigerant)

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Comfort
 All-inverter technology
 Continuous heating during oil return
 Night time quiet mode
 Backup function
Installation Advantages
 Light modular design
 Common footprint
 Automatic charge function
 Automatic test and self-diagnosis functions
 Improved electrical and refrigerant piping connections
 Automatic information storage
2. Sewage Treatment Plant
The quotation of STP has been confirmed with Diotech Systems and Projects,
Cochin which is one of the leading turnkey solutions providers of water and wastewater
treatment. The work is being executed according to the norms stated by the Pollution
Control Board. The waste water generated is being treated by SAFF METHOD The process
consists of Bar screen which removes all harmful materials like plastic cups, napkins
covers etc and various chemical treatments for safe land disposal. The sludge which is
resulting from the treatment is being pumped to the biogas plant which is again a
renewable source of energy. The treated water that is generated from the system can be
utilized for flushing, gardening etc.
2.1. Process Description
The treatment system consists of
• Primary Treatment System
• Biological Treatment System
• Tertiary Treatment System

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2.1.1. Primary Treatment System
1. Sewage Collection
A Septic Tank is provided for receiving the sewage from the building. The overflow
from the septic tank is directed to the collection cum equalization tank.
2.1.2. Biological Treatment System
1. Aerobic Treatment System

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The sewage from equalization tank is pumped to the aeration tank at a uniform
rate. The proposed Aerobic Treatment System shall have the following major components
a. Biological reactor (SAFF)
b. Aeration System
1. Biological reactor (SAFF)
The process employed in the biological reactor (SAFF) is extended aeration activated
sludge process. The waste water and active biomass is completely maintained in a
suspension and the MLSS is maintained at 3000-4000mg/L. The inlet of the aeration tank
is on the top with the waste water falling freely into the aeration tank. The outlet of the
aeration tank is connected to secondary settling tank. A recirculation of activated sludge is
maintained from bottom of the secondary settling tank to the aeration tank to maintain the
active biomass. The excess biomass will be directed to the Biogas Plant.
2. Aeration System
The air will be supplied by providing Air Blower (Twin Lobe) in the aeration tank for
degradation of organics by micro-organisms. The Aeration System consists of 2 Nos. Air
Blowers. One Blower shall be on duty while the other shall be on stand by. The Blowers
shall be used for aeration inside aeration tank.
2.1.3. Tertiary Treatment System
The supernatant from the clarifier tank will be collected in the clarified water sump.
The treated water is pumped through the Pressure Sand Filter for removal of the remaining
suspended particles followed by Activated Carbon Filter for removal of remaining organic
and colors. Chlorination is provided in the clarified water tank for disinfection purposes
with the help of a variable discharge metering pump of capacity along with a dosing tank.
The treated water can be utilized for the non-contact applications like gardening, floor
wash, and flushing purpose.

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3. Water Treatment Plant
The treatment system consists of:
 Collection and Aeration .
 Chemical Treatment
 Filtration System

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3.1. COLLECTION AND AERATION
The raw water is collected in the collection tank where a provision for Natural
Aeration is provided. Aeration will help to remove the organic wastes present in the water
if any and to precipitate and settle the iron content.
3.2. CHEMICAL TREATMENT SYSTEM
A mild dosage of Alum and Lime is done in to the collection tank. Lime is added for pH
neutralization purpose and Alum is added for coagulating the dissolved particles present in
the water and settling the same.
3.3. FILTRATION SYSTEM
There are four filtration units for the treatment. The water from the collection tank is
pumped through a Pressure Sand Filter for removing the remaining suspended particles, an
Activated Carbon Filter for removal of remaining organic and colors, a softener filter for
removing the hardness and finally through the RO membranes for removing the dissolved
solids and all other impurities. Backwash facility is provided for cleaning and maintenance
of the filters which is connected to the drain. The treated water is being stored in a treated
water tank, which can be further utilized for drinking, bathing and washing purpose.
3.4. Rain water harvesting
Kerala is a land of monsoons which give ample opportunity to harvest and reuse.
The rain water from the building is collected in a pit and reused in an herbal garden. There
are 2 pits at the amphitheatre where the rain water is collected and submerged in the
ground level area. Rain water harvesting system not only collects water within the
compound but also from the road and neighboring compounds. Instead of water flowing to
the sea, it is collected to corresponding pits within the compound to increase the ground
water level.

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4. Waste management
The proposal for waste management system has been sanctioned with No Waste. The
no fuel solid waste dispenser. No waste is an ecofriendly and economic solution for solid
waste disposal which runs on the principal of inceneration while addressing and solving
the major drawbacks of conventional incinerators like
a) Use of fuel and resultant environmental impacts
b) High initial investment
c) Recurring costs
d) Extensive space
‘NOWASTE’ works on Controlled Oxygen Rotating Technology incinerates solid waste by
combustion using atmospheric Oxygen, convert it into ash, heat, steam, and gas causing
minimal environmental impact. The manufacturing cost is comparatively very low, the fuel
free operation avoids recurring costs, and the compactness ensures minimum space for
installation.
Introduction of non CFC equipment for refrigeration and air conditioning
We are using air conditioners using VRF technology, which supports variable motor speed
and variable refrigerant flow rather than on/off operation. These features enable
substantial energy saving, allows individual units to heat or cool as required. Energy saving
upto 55% are predicted with this technology.
4.1 Bio Gas plant
Waste management involves a complex and wide range of occupational health and
safety relations. Waste management represents a reverse production process; the product
is removal of surplus materials. The original aim was simply to collect the materials, reuse
the valuable part of the materials and dispose of what remained at the nearest sites by eco
friendly and economically viable method.
Anaerobic digestion is a collection of processes by which microorganisms break down
biodegradable material in the absence of oxygen. The process is used for industrial or

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domestic purposes to manage waste and to produce fuels. The digestion process begins
with bacterial hydrolysis of the input materials. It is used as part of the process to treat
biodegradable waste and sewage sludge. As part of an integrated waste management
system, anaerobic digestion reduces the emission of landfill gas into the atmosphere.
Anaerobic digestion is widely used as a source of renewable energy. The process
produces a biogas, consisting of methane, carbon dioxide and traces of other contaminant
gases. This biogas can be used directly as fuel, in combined heat and power gas engines or
upgraded to natural gas quality bio methane. The nutrient rich digestate also produce can
be used as fertilizer.
4.1.1. Benefits and Advantages
In addition, biogas could potentially help to reduce global climate change. High levels
of methane are produce when manure is stored under anaerobic conditions. During storage
and when manure has been applied to the land, nitrous oxide is also produced as a
byproduct of the de nitrification process. Nitrous oxide (N2O) is 320 times more aggressive
than carbon dioxide and methane. i.e. the main advantages are it is a renewable source of
energy non polluting reduces landfills, cheaper technology, little capital investment,
reduces Green house effect.

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4.2. Incinerator
Global Incinerator- Role in Waste
management : Waste management is not that very
easy to maintain. In the modern world, the most
popular cities are being affected by constant threat
by pollution and waste gatherings. Though there
are recyclable materials piled up in the streets,
useful efforts have not been initiated by
municipality or corporation authorities. As a result,
various infections are spread over the country. All
types of inorganic waste has major role in this
process.
Prevention is better than cure. Prevention in the early stage is less expensive. We have
developed a new concept to prevent air pollution by waste management, to safeguard our
ever green culture. It will be a global message in future. It is Global incinerator- that never
disturbs nature.
Global Incinerators are manufactured under strict supervision by professional
experts to ensure long term service. We have made maximum efforts to reduce the cost of
the equipment, though we have adopted the most advanced technology with international
standard.
Global Incinerators are easy to operate always on safe mode, as long as the instructions are
strictly followed as per the training by our technical experts.
4.2.1. Operational Instructions:
1. Always separate the waste materials from restricted materials like, plastic, glass
bottles, empty tin cans, spray bottles, fuel based items, thermocol etc. before each
operation.

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2. Deposit wet and dry waste separately and burn the dry waste.
3. Use, fuel jet before burning.
4. Light up the waste and switch on the primary air blower till the flame rises up.
5. Close the chamber door firmly once the flames are steady and switch on the
secondary air blower to transfer the fumes to scrubber and sludge tank.
6. Switch off the blowers when beep signal comes from panel board.
7. Do not collect ash while the burning in progress.
4.2.2. Salient Features of Global Incinerators
1. Triple Chamber Equipment with Wet & Dry burning facilities.
2. Wet Scrubber, Three Stage Filtration, Fuel dropper jet, Water level indication
device, Panel Board with beep signals.
3. Burns 90% of the waste into ash as a result less smoke emission.
4. Used 'A' grade refractory fire bricks to withstand temperature up to 1200*C.
5. Flame guard maintains combustion efficiency and prevents flame spreading into
emission pipe.
7. Rock wool prevents heat transmission over the body.
8. Drain pipes to transfer sediments frequently.
9. G-3 epoxy coated outer body, protects from influence of Weather damages
4.2.3. Parts of equipment:
1. Combustion Chamber: Refractory Fire Bricks, Cast Iron Hearth, Air Blower, Flame
Guard ( Cast Iron- 12 mm thickness)
2. Master Emission Pipe: Double layered Cast Iron.

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3. Wet waste chamber: Cast Iron grills with refractory fire bricks, drain pipes, diesel
sprinkler jet
4. Scrubber: Wet scrubber technology
5. Sludge Tank: Stacks up sediments.
6. Pipe connections to fill the tank as well as drain outlet
7. Panel Board facility for timely operations and clear signals
8. Three Stage Filters : Fabric Filter (FF), Bristle Filter (BF), Wire Filter(WF)
9. Ash Deposit tray : Poly Coated Tray
10. Foundation: Reinforced concrete foundation
11. Flame Guard : Anti Corrosive Layer coated G.I. Sheet

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4.2.4. Precautions:
1. Do not peep inside the chamber while the burning in progress.
2. Always use safety equipment like gloves, masks, glass and stirring rod.
3. Wear apron made of cotton materials.
4. Remove unburned materials from hearth before the second burning, to help
sufficient air circulation
5. Drain the sludge tank and check water limit.
6. Beep signals indicate to switch off the air blowers.
7. Always keep the equipment surroundings clean. Do not stack up the waste nearby
the equipment.
8. Clear the ash frequently, do not wait till it over flows.
9. Do not pour water inside the equipment, this will cause damage to the hearth.
10. Always entrust trained persons to operate the equipment.
4.2.5. Advantages:
1. Simple and safe operation
2. Burns 90 % of the waste, as a result, less smoke emission.
3. Useful for domestic, medical & industrial waste managements
4. Triple chamber helps to burn both wet and dry waste.
5. Required limited space for installation.
6. Only equipment available with 3 years warrantee and half yearly cleaning of
accessories.
7. Low cost compared to others.

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5. Details of fire fighting measures/ Hydrants :
A fire fighting system is probably the most important of the building services, as
its aim is to protect human life and property, strictly in that order.
It 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.
5.1. Fire Hydrant
A fire hydrant is a vertical steel pipe with an outlet, close to which two fire hoses
are stored. 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 flow rate.
5.2. Sprinkler
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

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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 well at putting out fires before they spread and become unmanageable.
5.3. 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),
 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.

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5.4. 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:
 Area covered by hydrants / standpipes and sprinklers
 Number of hydrants and sprinklers
 Assumed area of operation of the sprinklers
 Type and layout of the building

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5.5. 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
Siamese 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.

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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 fireghting 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.

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 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.
6. Security related features
The safety of the guest is of paramount importance. The security measures start as
soon as the guest checks inside the hotel where the guest is made to walk through the
metal detector and his baggage is run through the luggage scanner. The guest rooms are
secured with the lock and key card system from Godrej India. Each bedroom door is fitted
with peep hole and internal securing device. There is a provision of Safe in the wardrobe of
guest rooms to keep expensive items like jewelry, cash etc and is password protected and
accessible by the guest only. The security related features are also used for the internal
stakeholders where the punching machine is used at the security Time Office for employees
during Time In and Time out. There are CCTV cameras located in every nook and corner of
the hotels.
6.1. CC TV
Closed-circuit television, commonly known as CCTV, is a video monitoring system in
which all of the circuits are closed and all of the elements are directly connected. This is
unlike broadcast television where any receiver that is correctly tuned can pick up the
signal. CCTV may employ point to point (P2P), point to multipoint, or wireless links.

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CCTV was first used in the 1940s by the company Siemens in Germany to observe
rockets launching. It went on to be installed in high-security locations such as banks, but
over the years CCTV has been used much more widely, most commonly associated with
security and surveillance, and its prevalence has fuelled privacy concerns in many parts of
the world.
CCTV systems use strategically placed video cameras, to capture footage and feed it to
either a private network of monitors for real-time viewing, or to a digital video recorder
(DVR) for future reference.
Older CCTV systems used small, low-resolution black and white
cameras and monitors with no interactive capabilities.
Modern CCTV systems display in full-colour and at high-definition.
This can be particularly helpful for facial recognition which can be
vital if analysis, investigation or legal proceedings are a possibility.
CCTV cameras have the ability to zoom in and pan to track action.
Motion sensors can be used to automatically record when there are
signs of movement. This can be particularly useful for home security.
Disc indexing and time-stamping make locating and accessing recoded
footage easier.
Night vision or Infra-red cameras can be used for applications
ranging from monitoring a sleeping baby, to carrying out surveillance in the heart of
combat zones.
A particular difficulty for large businesses is how to monitor multiple camera feeds in
a cost effective manner. Video analytics (or video content analysis VCA) can help
automate CCTV analysis recognising important features such as license plates, or patterns
of movement and allowing surveillance to focus on potentially important events.
CCTV may be operated as part of a wider building management system, allowing
related systems such as access controls, alarms, sensors and lighting to be integrated. This
can permit greater control, achieve better responses and give improved flexibility.

28. 28
CCTV images can be transmitted to a monitoring facility or can be accessed on
devices such as mobile phones, allowing responses to be directed remotely, such as police
or fire service action, or in some cases to permit access and de-activate alarms.
7. Elevator
An elevator or lift is a type of vertical transportation that moves people or goods
between floors (levels, decks) of a building or other structure. Elevators are generally
powered by electric motors that either drive traction cables or counterweight systems like
a hoist, or pump hydraulic fluid to raise a cylindrical piston like a jack.
The key parts of an elevator are:
 One or more cars (metal boxes) that rise up and down.
 Counterweights that balance the cars.
 An electric motor that hoists the cars up and down, including a braking system.
 A system of strong metal cables and pulleys running between the cars and the
motors.

29. 29
 Various safety systems to protect the passengers if a cable breaks.
 In large buildings, an electronic control system that directs the cars to the correct
floors using a so-called "elevator algorithm to ensure large numbers of people are
moved up and down in the quickest, most efficient way (particularly important in
huge, busy skyscrapers at rush hour). Intelligent systems are programmed to carry
many more people upward than downward at the beginning of the day and the
reverse at the end of the day.
The Gen2T.Nova system is the smart choice for 'green' buildings.
ReGen drive
A typical elevator includes three major components:
 Machine
 elevator car
 counterweight
The counterweight is designed to
balance a half-loaded car. Electrical power
is generated when a heavily-loaded car
travels in a 'down' direction or a lightly-
loaded car travels in an 'up' direction (green
area of graph). With a non-regenerative
drive the energy generated is dissipated in a
set of resistors creating a waste heat load in
the building.
With a regenerative drive, the energy
generated is fed back into the building's
grid where it can be used by other loads
connected to the same network. The energy
consumed with a non-regenerative drive is

30. 30
represented by the yellow area while with a regenerative drive the energy consumed is just
the difference between the yellow and green areas.
The amount of energy savings due to regeneration depends on various system
parameters and configurations such as
 Car load
 Speed
 Length of run
 Traffic pattern and
 System efficiency.
As the preferred choice for 'green' building initiatives, ReGen drives deliver substantial
energy savings while helping to meet or exceed established worldwide standards.
• Energy savings (up to 75%)
• Low harmonic distortion (typically below 5%) and reduced Radio Frequency
Interference.
• Operational cost savings through reduced peak power demand and decreased
energy consumption.
7.2. Environmental responsible
1. A 'green' machine
Neither the belts nor the gearless machine with sealed-for-life bearings require any
form of polluting lubricants. The low inertia gearless machine is equipped with a highly
efficient PM synchronous motor of radial construction.
The result is a machine which is up to:
 50% more efficient than conventional geared machines.
 10% more efficient than conventional gearless machines with induction
asynchronous motors.
 15% more efficient than other machines with PM motors of axial construction
design.

31. 31
2. A gearless machine with a closed-loop VF drive increases passenger
comfort.
The gearless machine combined with a sophisticated load weighing device and a
closed loop variable frequency drive with vector control contribute to a smooth and quiet
ride. Furthermore, they result in outstanding stopping accuracy of within +1- 3mm at every
landing.
7.3. The Gen2TM Nova elevator offers exceptional levels of performance.
 Faster operation
With adjustable acceleration
and deceleration rates, up to
0.6 m/s`. the Gen2T. Nova
elevator rapidly reaches its
nominal speed and
furthermore decelerates and
stops both smoothly and quickly.
7.4. While advanced security features demonstrate an absolute commitment to
both safety and reliability.
1. Safety features
For elevator users and service technicians.
• Door deterrent device
If the car is stopped between floors, a deterrent device prevents the car door from
opening. Hence a person cannot take the risk of exiting.
• Hoistway access detection
To protect a person entering the hoistway, a special safety feature prevents the elevator
from operating after a landing door has been opened.
• Rescue system

32. 32
Battery-operated rescue system with electronic speed monitoring enables the safe
and fast rescue of trapped passengers in the event of a power failure.
 Infra-red entrance protection
A screen of infrared beams acts as an invisible safety curtain. When an obstacle
breaks this screen, the sensitive 2D system detects it and immediately reopens the
doors.
 Stopping accuracy
The belt's reduced stretch compared to conventional steel ropes together with a
closed loop VF control results in outstanding stopping accuracy (within +/-3 mm at
every landing).
 Increased reliability
The PULSE' electronic system monitors the
status and integrity of the belt's steel cords
24/7d providing advance notice of the need for
replacement. Not only does this improve their reliability
and extend then life but it also reduces the downtime required for inspection.
7.5. Standard features
1. Anti- nuisance car call protection
The elevator identifies that there is only a single passenger load in the car but more
than three or four calls have been registered, it would then cancel the calls. This feature
is to prevent unnecessary movement due to playful children.
2. Independent service (for duplex only)
When the independent key switch is turned on, all registered hall calls are
cancelled and the elevator responds only to car calls. No hall calls can be registered
during this service.

33. 33
3. Overload device
When an overload is detected the car does not start and the doors remain open. The
elevator operation resumes only upon removal of the overload.
4. Nudging
If the doors are prevented from closing for a fixed period of time, a buzzer is activated
and the doors begin to close at a reduced speed.
5. Emergency firemen's service
This feature automatically places the car at the designated return landing with the
doors fully open. The fireman can then enter and take control of the elevator.
6. Emergency car light unit
An automatically rechargeable emergency power supply will switch on i ipon failure
of the normal lighting supply.
7. Infrared curtain door protection
Entrance protection system forms a safety net across the effective entrance area with
invisible Infrared beams that are able to detect passengers and objects in the path of
closing doors, within a fraction of second. Therefore, should a passenger enter or exit the
elevator just when the doors close, the system instantaneously reopens the elevator doors
allowing, the passengers to enter or exit freely.
Due to its design superiority even if a single beam is interrupted, the elevator door
opens automatically and remains open until the passenger clears the door way.
8. Door time protection
If the car door does not close completely within an adjustable time after the door
close command, the elevator will enter the DTC mode. remove itself from group operation.
Halt calls will be assigned to other elevators in the group. Open its doors and sound the

34. 34
buzzer in the car operating pane. Attempt closing the doors again. After three unsuccessful
retries, the car will shut down with its doors open, Pending car calls will be cleared_
9. Emergency alarm button
The emergency alarm hell located at the ground floor / lobby will be activated by
pressing the alarm button in the car operating panel, the device is powered by battery.
10.Extra door time of lobby & parking
The lobby door time is normally longer than the time at other landings to allow extra
passenger traffic at the lobby. Door timing is adjustable to suit the needs of the building:
11.Door open / close button
Door open / close button in the car operating panel permits independent. opening I
closing of automatic door, and to keep it open / dosed by constant pressure.
12.Manual rescue operation
The rescue of c.;eople trapped within the car is carried out by the manual inspection
rescue device. It allows the movement of the car to the closest floor.
13.Belt inspection device
Reliability and safety are further enhanced with Otis' PULSE Electronic system
which continually monitors the status of the belt's steel cords 24h/7d. Contrary to current
visual inspections of conventional steel ropes, the Otis PULSE" system automatically
detects and indicates through LED. This feature helps Otis technicians to monitor the
quality of the belt cord and greatly enhances the reliability of the inspection.

35. 35
8. SOLAR THERMALPOWER PLANT
Solar thermal energy (STE) is a form of energy and a technology for harnessing solar
energy to generate thermal energy or electrical energy for use in industry, and in the
residential and commercial sectors.
Solar thermal power plants use the sun's rays to heat a fluid to high temperatures. The
fluid is then circulated through pipes so that it can transfer its heat to water and produce
steam. The steam is converted into mechanical energy in a turbine, which powers a
generator to produce electricity.
Solar thermal power generation works essentially the same as power generation using
fossil fuels, but instead of using steam produced from the combustion of fossil fuels, the
steam is produced by heat collected from sunlight. Solar thermal technologies use
concentrator systems to achieve the high temperatures needed to produce steam.
8.1. Types of solar thermal power plants
There are three main types of solar thermal power systems:
 Parabolic trough
 Solar dish
 Solar power tower
8.1.1. Parabolic troughs
Parabolic troughs are used in the longest operating solar thermal power facility in the
world, which is located in the Mojave Desert in California.
The Solar Energy Generating System (SEGS) has nine
separate plants. The first plant, SEGS 1, has operated since
1984, and the last SEGS plant that was built, SEGS IX,
began operation in 1990. The SEGS facility is one of the
largest solar thermal electric power plants in the world.

36. 36
A parabolic trough collectorhas a long parabolic-shaped reflectorthat focusesthe sun's rays
on a receiverpipe located at the focusof the parabola. The collectortilts withthe sun as the sun
moves from east to west during the day to ensure that the sun is continuously focused on the
receiver.
Because of its parabolic shape, a trough can focus the sun from 30 times to 100 times
its normal intensity (concentration ratio) on the receiver pipe located along the focal line of
the trough, achieving operating temperatures higher than 750°F.
The solar field has many parallel rows of solar parabolic trough collectors aligned on a
north-south horizontal axis. A working (heat transfer) fluid is heated as it circulates
through the receiver pipes and returns to a series of heat exchangers at a central location.
Here, the fluid circulates through pipes so it can transfer its heat to water to generate high-
pressure, superheated steam. The steam is then fed to a conventional steam turbine and
generator to produce electricity. When the hot fluid passes through the heat exchangers, it
cools down, and is then recirculated through the solar field to heat up again.
The power plant is usually designed to operate at full power using solar energy alone,
given sufficient solar energy. However, all parabolic trough power plants can use fossil fuel
combustion to supplement the solar output during periods of low solar energy.
8.1.2. Solar dishes
Solar dish/engine systems use concentrating solar collectors that track the sun, so they
always point straight at the sun and concentrate the solar energy at the focal point of the
dish. A solar dish's concentration ratio is much higher than a solar trough's concentration
ratio, and it has a working fluid temperature higher than 1,380°F. The power-generating
equipment used with a solar dish can be mounted at the focal point of
the dish, making it well suited for remote operations or, as with the
solar trough, the energy may be collected from a number of
installations and converted into electricity at a central point. The
engine in a solar dish/engine system converts heat to mechanical
power by compressing the working fluid when it is cold, heating the compressed working

37. 37
fluid, and then expanding the fluid through a turbine or with a piston to produce work. The
engine is coupled to an electric generator to convert the mechanical power to electric
power.
8.1.3. Solar power tower
A solar power tower, or central receiver, generates electricity from sunlight by
focusing concentrated solar energy on a tower-mounted heat exchanger (receiver). This
system uses hundreds to thousands of flat, sun-tracking mirrors called heliostats to reflect
and concentrate the sun's energy onto a central receiver tower. The energy can be
concentrated as much as 1,500 times that of the energy coming in from the sun.
Energy losses from thermal-energy transport are minimized because solar energy is
being directly transferred by reflection from the
heliostats to a single receiver, rather than being
moved through a transfer medium to one central
location, as with parabolic troughs.
Power towers must be large to be economical.
This is promising technology for large-scale grid-
connected power plants. The U.S. Department of
Energy, along with a number of electric utilities, built and operated a demonstration solar
power tower near Barstow, California, during the 1980s and 1990s.
8.2. Technology
Most techniques for generating electricity from heat need high temperatures to achieve
reasonable efficiencies. The output temperatures of non-concentrating solar collectors are
limited to temperatures below 200°C. Therefore, concentrating systems must be used to
produce higher temperatures. Due to their high costs, lenses and burning glasses are not
usually used for large-scale power plants, and more cost-effective alternatives are used,
including reflecting concentrators.
The reflector, which concentrates the sunlight to a focal line or focal point, has a

38. 38
parabolic shape; such a reflector must always be tracked. In general terms, a distinction can
be made between one-axis and two-axis tracking: one-axis tracking systems concentrate
the sunlight onto an absorber tube in the focal line, while two-axis tracking systems do so
onto a relatively small absorber surface near the focal point (see Figure 1).
FIGURE 1. Concentration of sunlightusing (a) parabolic trough collector (b) linear Fresnel collector (c) central
receiver system with dish collector and (d) central receiver system with distributed reflectors
The theoretical maximum concentration factor is 46,211. It is finite because the sun
is not really a point radiation source. The maximum theoretical concentration temperature
that can be achieved is the sun’s surface temperature of 5500°C; if the concentration ratio
is lower, the maximum achievable temperature decreases. However, real systems do not

39. 39
reach these theoretical maxima. This is because, on the one hand, it is not possible to build
an absolutely exact system, and on the other, the technical systems which transport heat to
the user also reduce the receiver temperatures. If the heat transfer process stops, though,
the receiver can reach critically high temperatures.
8.2.1. Parabolic Trough Power Plants
Parabolic trough power plants are the only type of solar thermal power plant
technology with existing commercial operating systems until 2008. In capacity terms, 354
MWe of electrical power are installed in California, and a plenty of new plants are currently
in the planning process in other locations.
FIGURE . Schematic of a concentrated solar thermal trough power plant with thermal
storage
The parabolic trough collector consists of large curved mirrors, which concentrate the
sunlight by a factor of 80 or more to a focal line. Parallel collectors build up a 300–600
metre long collector row, and a multitude of parallel rows form the solar collector field. The
one-axis tracked collectors follow the sun.

40. 40
The collector field can also be formed from very long rows of parallel Fresnel collectors. In
the focal line of these is a metal absorber tube, which is usually embedded in an evacuated
glass tube that reduces heat losses. A special high-temperature, resistive selective coating
additionally reduces radiation heat losses.
In the Californian systems, thermo oil flows through the absorber tube. This tube heats up
the oil to nearly 400°C, and a heat exchanger transfers the heat of the thermal oil to a water
steam cycle (also called Rankine cycle). A feedwater pump then puts the water under
pressure. Finally, an economizer, vaporizer and superheater together produce superheated
steam. This steam expands in a two-stage turbine; between the high-pressure and low-
pressure parts of this turbine is a reheater, which heats the steam again. The turbine itself
drives an electrical generator that converts the mechanical energy into electrical energy;
the condenser behind the turbine condenses the steam back to water, which closes the
cycle at the feedwater pump.
It is also possible to produce superheated steam directly using solar collectors. This makes
the thermo oil unnecessary, and also reduces costs because the relatively expensive thermo
oil and the heat exchangers are no longer needed. However, direct solar steam generation
is still in the prototype stage.
8.2.2. Guaranteed Capacity
In contrast to photovoltaic systems, solar thermal power plants can guarantee
capacity (see Figure 2). During periods of bad weather or during the night, a parallel, fossil
fuel burner can produce steam; this parallel burner can also be fired by climate-compatible
fuels such as biomass, or hydrogen produced by renewables. With thermal storage, the
solar thermal power plant can also generate electricity even if there is no solar energy
available.
A proven form of storage system operates with two tanks. The storage medium for
high-temperature heat storage is molten salt. The excess heat of the solar collector field
heats up the molten salt, which is pumped from the cold to the hot tank. If the solar
collector field cannot produce enough heat to drive the turbine, the molten salt is pumped

41. 41
back from the hot to the cold tank, and heats up the heat transfer fluid. Figure 3 shows the
principle of the parabolic trough power plant with thermal storage.
8.2.3. Solar Thermal Tower Power Plants
In solar thermal tower power plants, hundreds or even thousands of large two-axis
tracked mirrors are installed around a tower. These slightly curved mirrors are also called
heliostats; a computer calculates the ideal position for each of these, and a motor drive
moves them into the sun. The system must be very precise in order to ensure that sunlight
is really focused on the top of the tower. It is here that the absorber is located, and this is
heated up to temperatures of 1000°C or more. Hot air or molten salt then transports the
heat from the absorber to a steam generator; superheated water steam is produced there,
which drives a turbine and electrical generator, as described above for the parabolic trough
power plants. Only two types of solar tower concepts will be described here in greater
detail.
8.2.4. Open Volumetric Air Receiver Concept
The first type of solar tower is the open volumetric receiver concept (see Figure 4a).
A blower transports ambient air through the receiver, which is heated up by the reflected
sunlight. The receiver consists of wire mesh or ceramic or metallic materials in a
honeycomb structure, and air is drawn through this and heated up to temperatures
between 650°C and 850°C. On the front side, cold, incoming air cools down the receiver
surface. Therefore, the volumetric structure produces the highest temperatures inside the
receiver material, reducing the heat radiation losses on the receiver surface. Next, the air
reaches the heat boiler, where steam is produced. A duct burner and thermal storage can
also guarantee capacity with this type of solar thermal power plant.
8.2.5. Pressurized Air Receiver Concept
The volumetric pressurized receiver concept (see Figure 4b) offers totally new
opportunities for solar thermal tower plants. A compressor pressurizes air to about 15 bar;
a transparent glass dome covers the receiver and separates the absorber from the

42. 42
environment. Inside the pressurized receiver, the air is heated to temperatures of up to
1100°C, and the hot air drives a gas turbine. This turbine is connected to the compressor
and a generator that produces electricity. The waste heat of the gas turbine goes to a heat
boiler and in addition to this drives a steam-cycle process. The combined gas and steam
turbine process can reach efficiencies of over 50%, whereas the efficiency of a simple
steam turbine cycle is only 35%. Therefore, solar system efficiencies of over 20% are
possible.
FIGURE 4. Schematic of two types of solar thermal tower power plant, showing (a) an
open volumetric receiver with steam turbine cycle and (b) a pressurized receiver
with combined gas and steam turbine cycle

43. 43
8.2.6. Comparing Trough and Tower
In contrast to the parabolic trough power plants, no commercial tower power plant
exists at present. However, prototype systems – in Almería, Spain, in Barstow, California,
US, and in Rehovot, Israel – have proven the functionality of various tower power plant
concepts.
The minimum size of parabolic trough and solar tower power plants is in the range of
10 MWe. Below this capacity, installation and O&M costs increase and the system efficiency
decreases so much that smaller systems cannot usually operate economically. In terms of
costs, the optimal system size is in the range of 50–200 MWe.
8.2.7. Dish-Stirling Systems
So-called Dish–Stirling systems can be used to generate electricity in the kilowatts
range. A parabolic concave mirror (the dish) concentrates sunlight; the two-axis tracked
mirror must follow the sun with a high degree of accuracy in order to achieve high
efficiencies. In the focus is a receiver which is heated up to 650°C. The absorbed heat drives
a Stirling motor, which converts the heat into motive energy and drives a generator to
produce electricity. If sufficient
sunlight is not available,
combustion heat from either
fossil fuels or biofuels can also
drive the Stirling engine and
generate electricity. The
system efficiency of Dish–
Stirling systems can reach 20%
or more. Some Dish–Stirling system prototypes have been successfully tested in a number
of countries. However, the electricity generation costs of these systems are much higher
than those for trough or tower power plants, and only series production can achieve
further significant cost reductions for Dish–Stirling systems.

44. 44
8.2.8. Solar Chimney Power Plants
All three technologies described above can only use direct normal irradiance.
However, another solar thermal power plant concept – the solar chimney power plant –
converts global irradiance into electricity. Since chimneys are often associated negatively
with exhaust gases, this concept is also known as the solar power tower plant, although it is
totally different from the tower concepts described above. A solar chimney power plant has
a high chimney (tower), with a height of up to 1000 metres, and this is surrounded by a
large collector roof, up to 130 metres in diameter, that consists of glass or resistive plastic
supported on a framework (see artist’s impression). Towards its centre, the roof curves
upwards to join the chimney, creating a funnel.
The sun heats up the ground and
the air underneath the collector roof,
and the heated air follows the upward
incline of the roof until it reaches the
chimney. There, it flows at high speed
through the chimney and drives wind
generators at its bottom. The ground
under the collector roof behaves as a
storage medium, and can even heat up
the air for a significant time after sunset. The efficiency of the solar chimney power plant is
below 2%, and depends mainly on the height of the tower, and so these power plants can
only be constructed on land which is very cheap or free. Such areas are usually situated in
desert regions.
However, the whole power plant is not without other uses, as the outer area under
the collector roof can also be utilized as a greenhouse for agricultural purposes. As with
trough and tower plants, the minimum economical size of solar chimney power plants is
also in the multi-megawatt range.

45. 45
9. WINDPOWER GENERATION
The wind is a source of free energy which has been used since ancient times in
windmills for pumping water or grinding flour. The technology of high power, geared
transmissions was developed centuries ago by windmill designers and the fantail wheel for
keeping the main sales pointing into the wind was one of the world's first examples of
an automatic control system.
9.1. Fixed Speed Wind Turbine Generators
A typical fixed speed system employs a rotor with three variable pitch blades which
are controlled automatically to maintain a fixed rotation speed for any wind speed. The
rotor drives a synchronous generator through a gear box and the whole assembly is housed
in a nacelle on top of a substantial tower with massive foundations requiring hundreds of
cubic metres of reinforced concrete.
Fixed speed systems may however suffer
excessive mechanical stresses. Because they
are required to maintain a fixed speed
regardless of the wind speed, there is no "give"
in the mechanism to absorb gusty wind forces
and this results in high torque, high stresses
and excessive wear and tear on the gear box increasing maintenance costs and reducing
service life. At the same time, the reaction time of these mechanical systems can be in the
range of tens of milliseconds so that each time a burst of wind hits the turbine, a rapid
fluctuation of electrical output power can be observed. Furthermore, variable speed wind
turbines can capture 8-15% more of the wind's energy than constant speed machines. For
these reasons, variable speed systems are preferred over fixed speed systems. See more
about the properties of synchronous generators.

46. 46
9.2. Variable Speed Wind Turbine Generators
A variable speed generator is better able to cope with stormy wind conditions because
its rotor can speed up or slow down to absorb the forces when bursts of wind suddenly
increase the torque on the system. The electronic control systems will keep the generator's
output frequency constant during these fluctuating wind conditions.
 Synchronous Generator with In-Line Frequency Control
Rather than controlling the turbine rotation speed to obtain a fixed frequency
synchronised with the grid from a synchronous generator, the rotor and turbine can be
run at a variable speed corresponding to the prevailing wind conditions. This will
produce a varying frequency output from the generator synchronised with the drive
shaft rotation speed. This output can then be rectified in the generator side of an AC-
DC-AC converter and the converted back to AC in an inverter in grid side of the
converter which is synchronised with the grid frequency. See following diagram. The
grid side converter can also be used to provide reactive power (VArs) to the grid for
power factor control and voltage regulation by varying the firing angle of the thyristor
switching in the inverter and thus the phase of the output current with respect to the
voltage. See an explanation and more details of why reactive power is needed in the
section about Power Quality and Voltage Support as used in the utility grid.

47. 47
The range of wind speeds over which the system can be operated can be extended and
mechanical safety controls can be incorporated by means of an optional speed control
system based on pitch control of the rotor vanes as used in the fixed speed system
described above.
One major drawback of this system is that the components and the electronic control
circuits in the frequency converter must be dimensioned to carry the full generator
power. The doubly fed induction generator DFIG overcomes this difficulty.
9.3. Doubly Fed Induction Generator - DFIG
DFIG technology is currently the preferred wind power generating technology. The
basic grid connected asynchronous induction generator gets its excitation current from
the grid through the stator windings and has limited control over its output voltage and
frequency. The doubly fed induction generator permits a second excitation current
input, through slip rings to a wound rotor permitting greater control over the generator
output.
The DFIG system consists of a 3 phase wound rotor generator with its stator windings
fed from the grid and its rotor windings fed via a back to back converter system in a
bidirectional feedback loop taking power either from the grid to the generator or from
the generator to the grid. See the following diagram.

48. 48
 Generator Operating Principle
The feedback control system monitors the stator output voltage and frequency and
provides error signals if these are different from the grid standards. The frequency
error is equal to the generator slip frequency and is equivalent to the difference
between the synchronous speed and the actual shaft speed of the machine.
The excitation from the stator windings causes the generator to act in much the
same way as a basic squirrel cage or wound rotor generator, (See more about the
properties of induction generators and how they work.). Without the additional
rotor excitation, the frequency of a slow running generator will be less than the grid
frequency which provides its excitation and its slip would be positive. Conversely if
it was running too fast the frequency would be too high and its slip would be
negative.
The rotor absorbs power from the grid to speed up and delivers power to the grid in
order to slow down. When the machine is running synchronously the frequency of
the combined stator and rotor excitation matches the grid frequency, there is no slip
and the machine will be synchronised with the grid.
 Grid Side Converter - GSC : Carries current at the grid frequency. It is an AC to
DC converter circuit used to provide a regulated DC voltage to the inverter in the
machine side converter (MSC). It is used maintain a constant DC link voltage. A
capacitor is connected across the DC link between the two converters and acts
as an energy storage unit. The grid side converter is used to maintain a constant
DC link voltage. In the opposite direction the GSC invereter delivers power to
the grid with the grid regulated frequency and voltage.
As with the in-line converter described above, by adjusting the timing of the GSC
inverter switching, the GSC converter also provides variable reactive power
output to counterbalance the reactive power drawn from the grid enabling
power factor correction as in the in-line frequency control system described
above.

49. 49
 Machine Side Converter - MSC: Carries current at slip frequency. It is an DC to
AC inverter which is used to provide variable AC voltage and frequency to the
rotor to control the torque and speed of the machine.
When the generator is running too slowly, its frequency will be too low so that it
is essentially motoring. The machine side converter takes DC power from the DC
link and provides AC output power at the slip frequency to the rotor to eliminate
its motoring slip and thus increase its speed. If the rotor is running too fast
causing the generator frequency to be too high, the MSC extracts AC power from
the rotor at the slip frequency causing it to slow down, reducing the generator
slip, and converts the rotor output to DC passing it through the DC link to the
GSC where it is converted to the fixed grid voltage and frequency and is inserted
into the grid.
9.4. Domestic Wind Turbine Installations
In a typical domestic system the wind turbine is coupled directly to a three phase
asynchronous permanent magnet AC generator mounted on the same shaft. To save on
capital costs, domestic installations do not have variable pitch rotor blades so the rotor
speed varies with the wind speed. The generator output voltage and frequency are
proportional to the rotor speed and the current is proportional to the torque on the shaft.
The output is rectified and fed through a buck-boost regulator to an inverter which
generates the required fixed amplitude and frequency AC voltage.

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10. GREEN CERTIFICATE
A Green Certificate - terminology predominantly used in Europe but now
becoming more widespread globally - are a tradable commodity proving that certain
electricity is generated using renewable energy sources. Typically one certificate
represents generation of 1 Megawatt hour of electricity. What is defined as "renewable"
varies from certificate trading scheme to trading scheme. Usually, at least the following
sources are considered as renewable:
 Wind (often further divided into onshore and offshore)
 Solar (often further divided into photovoltaic and thermal)
 Wave (often further divided into onshore and offshore) and tidal (often further divided
into onshore and offshore)
 Geothermal
 Hydro (often further divided into small - microhydro - and large)
 Biomass (mainly biofuels, often further divided by actual fuel used).
Green certificates represent the environmental value of renewable energy
generated. The certificates can be traded separately from the energy produced. Several
countries use green certificates as a mean to make the support of green electricity
generation closer to a market economy instead of more bureaucratic investment support
and feed-in tariffs. Such national trading schemes are in use in e.g. Poland, Sweden, the UK,
Italy, Belgium (Wallonia and Flanders), and some US states.
Once in the grid, renewable energy is impossible to separate from the
conventionally generated energy. This makes purchasing of a green certificate equal to
purchasing a claim, that the certificate owner consumed energy from the renewable
portion of the whole energy in the grid. Therefore certificate purchase does not affect how
much renewable energy was actually generated - only how it was distributed.
In contrast to CO2e-Reduction certificates, e.g. AAU's or CER's under the UNFCC, which can
be exchanged worldwide, Green Certificates cannot be exchanged/traded between e.g.
Belgium and Italy, let alone the USA and the EU member States.

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