Green building concepts: Business Segment Green Building, an energy efficient sustainable building is designed in an ecological and resource efficient manner with an objective of healthy environment, improves productivity and using energy and other resources efficiently. It mainly focussed on Integration of Renewable Energy Technologies in particular Solar Energy, Building material & Energy Conservation. It emphasis an effective utilisation of Energy and analysis of option of alternate energy with an overall reduction of energy consumption.

1. Intergen Energy Ltd.
Business Segment
Reverse Osmosis
Reverse osmosis (RO) is a membrane technical filtration method that removes many types of large
molecules and ions from solutions by applying pressure to the solution when it is on one side of a
selective membrane. The result is that the solute is retained on the pressurized side of the membrane
and the pure solvent is allowed to pass to the other side. To be "selective," this membrane should not
allow large molecules or ions through the pores (holes), but should allow smaller components of the
solution (such as the solvent) to pass freely.
RO process for water purification does not require thermal energy. Flow through RO system can be
regulated by high pressure pump. The recovery of purified water depends upon various factors including
membrane sizes, membrane pore size, and temperature, operating pressure and membrane surface
area.
Waste Water and Sewage Treatment
Most wastewater is treated in industrial-scale wastewater treatment plants (WWTPs) which may include
physical, chemical and biological treatment processes. The most important aerobic treatment system is
the activated sludge process, based on the maintenance and recirculation of a complex biomass
composed by micro-organisms able to absorb and adsorb the organic matter carried in the wastewater.

2. Anaerobic processes are widely applied in the treatment of industrial wastewaters and biological sludge.
Some wastewater may be highly treated and reused as reclaimed water. For some waste waters
ecological approaches using reed bed systems such as constructed wetlands may be appropriate.
Modern systems include tertiary treatment by micro filtration or synthetic membranes. After membrane
filtration, the treated wastewater is indistinguishable from waters of natural origin of drinking quality.
Nitrates can be removed from wastewater by microbial de-nitrification, for which a small amount of
catalyst is typically added to provide the bacteria with a source of carbon. Ozone Waste Water
Treatment is also growing in popularity, and requires the use of an ozone generator, which
decontaminates the water as Ozone bubbles percolate through the tank.
Bio-Mass
Biomass can be routed through following different processes for energy conversion:
Direct Combustion
Thermal decomposition of organic matter is carried out in the presence of excess air, liberating heat and
leaving behind incombustible ash.
Fuel + Air ? Heat + Ash + Inert Gases
In the combustion mode, the Biomass and air are combined under efficient and controllable conditions
to provide energy for utilization. The direct combustion of Biomass can be done in two ways:
• Fixed Bed Combustion
The combustion of Biomass is usually carried out in fixed bed combustors. The main drawback of fixed
bed combustion is a low combustion efficiency of 70%. It is associated with problems of ash removal and
inability to use effectively high moisture content Biomass. Further, fixed combustion involves high
inventory of fuel over the grate resulting in time consuming start-up and shut down procedures.
• Fluidised bed combustion

3. In a fluidized bed system, a bed of fine particles is fluidized by a gas stream passing upwards through it
at a controlled velocity. The bed is continuously subjected to high rate of mixing and agitation resulting
in high heat and mass transfer rates. Fluidised bed combustion is best suited for burning fuels like rice
husk etc.
The advantages of fluid bed combustion over fixed bed combustion are high combustion efficiency
(95%), multi-fuel combustion facility, and consistent rate of combustion and ability to burn low grade
and high moisture content fuels.
Gasification
Gasification is the thermo-chemical process of obtaining energy from solid matter in a gaseous form. In
principle, the process is a thermal decomposition of organic matter in the presence of limited supply of
air or oxygen to produce combustible gases thus converting calorific value of organic material into a
gaseous energy carrier. The amount of electricity that can be produced from Biomass power systems
can be increased by 50% by replacing steam based generation units with Biomass gasifiers close-coupled
to gas turbines.
Pyrolysis
In contrast to complete combustion of solid carbonaceous material, the process of pyrolysis refers to
combustion in a deficient supply of air / oxygen. The process gives out carbon-mono-oxide and
methane, which are condensed to form tar and aqueous liquor. The latter is then distilled to give
methanol and other organic substances. This process produces three useful fuels - charcoal, oil and gas.
About 70% of the energy in Biomass can be converted to higher forms of energy - charcoal or oil, which
are storable and transportable.
Small Hydro Power
Small Hydropower is a renewable, non-polluting and environmental friendly source of energy. It is
perhaps the oldest renewable energy technique known to the mankind for mechanical energy
conversion as well as electricity generation.

4. Hydropower represents use of water resources towards low cost energy generation with mature
technology characterized by high efficiency and operational flexibility.
Hydroelectric power is the generation of electric power from the movement of water. A hydroelectric
facility requires a dependable flow of water and a reasonable height of fall of water, called the head. In a
typical installation, water is fed from a reservoir through a channel or pipe into a turbine. The pressure
of the flowing water on the turbine blades causes the shaft to rotate. The rotating shaft is connected to
an electrical generator which converts the motion of the shaft into electrical energy.
Solar Energy
Energy from the sun not only sustains life an earth but is also the source of almost all forms of energy
used by man. Solar energy, experienced by us as heat and light, can be used in a number of ways and for
many applications such as:
Thermal route - using the heat for heating, cooling, drying, water purification and power generation.
Photovoltaic route - converting the light energy into electric energy which can then be used for a variety
of purposes such as lighting, pumping, communications and refrigeration etc.
Producing electricity from solar resource through:
- Concentrating solar thermal
- Solar photovoltaic
Concentrating solar thermal route uses the heat component of solar energy. Heat is used directly or
through an intermediate fluid to generate steam which is expands in steam turbine to produce
electricity.
Solar cells convert solar radiation (sunlight) directly into electricity by photoelectric/photovoltaic effect.
Incident photons (light ray) strike on the photovoltaic cell, and knock off electrons. These free electrons
start flowing through a circuit forming an electrical current.
Photovoltaic module contains a group of photovoltaic cells, connected mostly in series and encapsulated
between a layer of front glass, EVA and back cover. The high transmissivity, toughened glass cover is

5. used to ensure high light absorption and therefore enhance the performance of the cells. Solar radiation
falls directly upon the photovoltaic cell and produce DC electricity.
Photovoltaic cells absorb both direct and diffuse solar radiation. Generally, flat plate photovoltaic
modules/panels are mounted in a fixed position and tilted towards south (locations in northern
hemisphere) to optimize energy production. However, flat plate PV panels with tracking mechanism
(one/two axis) increase output of solar panels, particularly for high DNI.
The amount of power that a PV panel delivers is proportional to the amount of radiation that falls upon
it. The advantages of PV system as compared to solar thermal are as follows:
- It is modular in nature so that any size of system could be installed.
- It is suitable for relatively colder climates
- It is nearly maintenance free
- Less water requirement
- It does not make any noise
The various types of solar cells used for electricity generation are as follows:
Crystalline
The most common commercial crystalline solar cells are made up from silicon wafers. These account for
about 85%[ ] of the world’s solar PV industry. Silicon wafers either consists of one large singe crystal,
called single crystalline wafers, or consist of crystallites in a single wafer, are known as polycrystalline
(multi-crystalline) silicon wafers. The main advantages of cells produced from mono-crystalline (mono-
Si) and polycrystalline (poly-Si) silicon wafers are: suit relatively small areas and have higher efficiency.
The efficiency achieved by a crystalline solar cell depends on the processing technology used to make
the solar cell. The most commonly used technology to make wafer-based silicon solar cells is screen-
printed technology.
Thin Film
Thin film solar cells are made up from a variety of materials, with the key features being that the
thickness of the cells is a few microns. Thin film solar cells are made from amorphous silicon (a-Si),
cadmium telluride (CdTe) and copper indium di-selenide (CIS). Thin film technology is comparatively
cheaper, but produces less output per unit area due to its lower efficiency, so it requires large area per
unit output.
The main advantages of cells produced from thin films are low cost of production and they can be made
with requisite shape as per the requirement. But, unfortunately there are limitations of utility
properties. However, it is possible to improve the utility properties of amorphous cells by means of
changing the cross section of the window layer to improve sun light collection efficiency.
Other

6. There are some other PV materials for solar cells like string ribbon silicon wafers (ribbon-hetero-junction
with intrinsic thin layer hybrid silicon solar cell (HIT) and concentrator photovoltaic solar cell etc.
Waste to Energy
Wastes generated from various sources can be converted to energy through different technologies such
as Anaerobic digestion / Biomethanation, Combustion / Incineration, Pyrolysis / Gasification, Landfill Gas
recovery, Plasma arc. The organic fraction of the waste need to be segregated and fed into required
process. The option of technologies is detailed in Biomass segment.
Wind Energy
Wind Energy is the kinetic energy associated with the movement of atmospheric air. Wind Energy
Systems convert this kinetic energy to more useful forms of power. Wind turbine transforms the energy
in the wind into mechanical power, further converting to electric power to generate electricity. Wind
turbine can be used singly or in clusters called 'Wind Farms'. Small wind turbines called aero-generators
can be used for water pumping, battery charging etc.
Green building concepts:

7. Green Building, an energy efficient sustainable building is designed in an ecological and resource
efficient manner with an objective of healthy environment, improves productivity and using energy and
other resources efficiently. It mainly focussed on Integration of Renewable Energy Technologies in
particular Solar Energy, Building material & Energy Conservation. It emphasis an effective utilisation of
Energy and analysis of option of alternate energy with an overall reduction of energy consumption.