NON
CONVENTIONAL
POWERPLANT
BY: ENGR EJAY P. MARASIGAN
Non-conventional Energy
Sources
• Non-conventional
Energy Sources – also referred to as
renewable energy sources, these are actually energy
flows which are replenished as they are used, hence,
the use of the term renewable. These are
characterized by a maximum theoretical rate at which
energy may be extracted in a renewable mode, that is,
the rate at which new energy is arriving or flowing into
the reservoirs associated with many of the renewable
energy flows. All forms of energy sources with the
exception of geothermal energy, salinity gradient and
tidal energy are indirect manifestations of SOLAR
ENERGY.
Solar Power
There are many applications for the direct use of solar
thermal energy, space heating and cooling, water heating,
crop drying and solar cooking.
Qs = Qw + PE +Qloss
Qs = Solar energy w/o interference
Es = Qs (1-i ) (Ac) = E (Ac)(α)(τ)
Es = Energy received at Earth’s Surface
Ac = Collector’s Area i = Atmospheric interference
α = Absorptivity
τ = Transmissivity
1=
Solar Constant = E =1353 W/m2
Useful energy from the sun is between 10 AM – 2 PM =
1000 W/m2
Photovoltaic cell – is a device which converts solar
energy to electrical energy.
A solar collecting panel 20m2 in area receives solar
energy at the rate of 750 W/m2. It is estimated that
35% of the incident energy is lost to surroundings.
Waters enters the panel at steady flow rate of 0.05kg/s
at 15 degC. Calculate the temperature of water leaving
the collecting panel. Change in elevation of water is 2
meters.
61.56 degC
The sun generates an average of 2kW/m2 when tapped
as source of energy where in a flat plate collector with
an area of 1.5m2 is used. Flow rate of water inside the
collector is 40L/hr. Calculate for the temperature rise of
the working fluid in dec C.
65.14 degC
A plate – type solar energy collector with an absorbing
surface covered by a glass plate is to receive an
incident radiation of 800 W/m2. The glass plate has a
reflective of 0.12 and a transmissivity of 0.85. The
absorbing surface has an absorptivity of 0.90. The area
of the collector is 5m2. How much solar energy in watts
is absorbing by the collector?
3060 watts
Wind Power
Betz’s law – is a theory about the maximum possible
energy to be derived from a wind turbine. The ideal or
maximum theoretical efficiency, also called power
coefficient, of a wind turbine is the ratio of maximum
power from the wind to the total power available in the
wind. The factor 0.593 is known as Betz’s coefficient. It
is the maximum fraction of the power in a wind stream
that can be extracted.
An American type wind will with an aerodynamic
efficiency of 10% is wanted to pump 38 L/min from well
to a tank located at 18.3 m above the water surface of
the well when the wind has a velocity of 30 kph.
Consider that the frictional losses of the system divert
30% of the energy received by the wheel. What wheel
diameter is needed?
2.5
Our country is embarking into the use of renewable
energy resources like wind power to save on its energy
needs. Determine the maximum power in kW that may
be derived from a 55 kph wind if the wind rotor to be
used has blade diameter of 32 m and the over-all
conversion efficiency maybe taken as 35%. Average air
pressure is 100 kPa and ambient temperature of 32 deg
C must be assumed.
573.4 kW
A windmill with a 6m radius rotor is to be installed
where atmospheric pressure conditions prevail at
101.325 kPa and 21degC. It was observed that wind is
blowing steadily at an average velocity of 20m/s.
Assuming that the conversion efficiency is somewhere
in between 20-25%, determine the maximum available
power from the windmill.
34 kW
TIDAL POWER
Tidal power – is basically hydro-electric power utilizing the
difference in elevation between high and low tide to produce
energy. A basin is required to catch the sea water during high
tide while the water drives the turbine.
In the Philippines, commercialization is not full-scale since it is
found that the average difference is only about 6
meters.
OCEAN THERMAL ENERGY CONVERSION (OTEC)
This is otherwise known as low thermal head plant, it utilizes
the temperature difference between the ocean surface water
and the water at the sea bottom. Surface water which is at
relatively high temperature is pumped to an evaporator where
the water evaporates into saturated steam. This steam drives a
single stage turbine thereby producing electricity, and exhaust
to a jet condenser maintained at the saturation pressure of the
subsurface water temperature pumped from the sea bottom.
An Ocean Thermal Energy Conversion power plant
generates 10,000 kW using a warm surface water inlet
temperature of 26 deg C and cold deep-water
temperature of 15 deg C. On the basis of 3 def C drop
in the temperature of the warm water and 3 deg C rise
in the temperature of the cold water due to removal
and addition of heat, calculate the power required in
kW to pump the cold deep-water to the surface and
through the system heat exchanger if the required
pumping pressure increase is 12 kPa. Assume a Carnot
cycle efficiency and density of cold water to be 1000
kg/m3.
250.12 kW
Nuclear Power Plant
NUCLEAR FUSION
NUCLEAR FISSION (Pierre Curie, Marie Curie)
Nuclear
•
= enriched Uranium
= Fissionable portion of the fuel
A 600 MWe PWR nuclear plant uses 4% enriched
Uranium fuel has a thermal efficiency of 36%. The burn
up allowed of the fissionable portion of the fuel is 20%.
Calculate how many metric tons of natural Uranium is
placed in the reactor vessel for one year continuous
operation. Note: Heating Equivalent is 23,000 kW-hr/g
U235
79.35