Economic Design of OTEC Power Plant with Concurrent Production of Desalinated Water – A Case Study | Chapter 3 | Theory and Applications of Chemistry Vol. 2
Ocean
Thermal Energy Conversion (OTEC) power plants offer a green source of renewable
energy. Since India is
a tropical country
and a peninsula, the prospects
of OTEC power generation
are extremely bright in India. Among the three modes of operation (open
cycle, closed cycle and hybrid cycle) of OTEC system, the hybrid mode is most
promising. However, one of the
chief technical obstacles in OTEC
power plant design is that since the temperature difference driving force
available is of the order
of 10-15ºC only, the size
of the heat exchanger (evaporator / condenser) required becomes
exorbitantly large. The use of variable area design, developed by the author
and his co-workers, has been recommended in this connection. Such a design
provides substantial increase in heat transfer coefficient (350 to 450%
increase) with insignificant increase in the associated pressure drop penalty
(118 to 120% increase). The required size of
the heat exchangers thus gets
reduced tremendously, while the
operating cost does
not increase materially,
thereby making design
and operation of OTEC power plants economical and cost-effective. The
performance characteristics of such heat exchangers (Variable Area Heat
Exchangers or VAEs) are discussed in detail in this paper. Further, in the
hybrid mode of operation of OTEC system,
low pressure steam is produced by the
flash evaporation of sea water and this steam is used as heating fluid in the
evaporator (of variable area design) to evaporate the working fluid (ammonia,
freon). The condensate from this exchanger thus
forms desalinated water,
which constitutes a
valuable by-product of
the process. Apart from
generating clean electric power around the clock (without consuming any
valuable raw material), this power plant thus produces several gallons of
desalinated water also per day.
Author(s) Details
Prof. (Dr.) C. M.
Narayanan
Department of Chemical Engineering, National Institute of Technology, Durgapur 713209, India.
View Volume: https://doi.org/10.9734/bpi/tac/v2Department of Chemical Engineering, National Institute of Technology, Durgapur 713209, India.
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