Environmental Engineering Reference
In-Depth Information
Fig. 7.14
Research and
development of EMS control
hot spring thermal energy
system. (NET
2013
)
transport modes will provide recovering localities with next-generation mobility
management. Finally, in emergency conditions, evacuation coordination showing
open routes, emergency transportation management, and energy transfer manage-
ment utilizing EVs will be possible, to improve mobility during disasters and to
save lives in localities stricken by future earthquakes.
A trial of an EMS-controlled geothermal system will be conducted at Naruko
Town (Osaki City) experimental installation. This is one of Japan's many hot springs
where there is an abundance of low temperature heat, as well as residues from local
rice production which provide a source of biomass. Research is underway (Fig.
7.14
)
in cooperation with local governments to develop a binary geothermal power gen-
eration system that operates efficiently at low temperatures, combined with energy
recovery by methane fermentation of biomass residues. Currently energy conver-
sion efficiency is as low as 7 % or less, but this is promising as a means of natural
energy utilization equipment in local communities. The current method is to use hot
spring water to heat the heat transfer medium (ammonia and water mixture) on the
primary side of the evaporator. The inlet temperature of about 100 ºC is reduced to
about 70 ºC which is still sufficient residual heat for greenhouse cultivation.
An additional potential use for residual heat is to support a hybrid methane fer-
mentation system using cow rumen fluid and rumen microorganisms to digest her-
baceous woody biomass which is unused by general biomass processes (Fig.
7.15
).
Combining electricity generation from low grade geothermal heat and methane from
fermentation of food and other organic waste provides a valuable energy source for
a hot spring inn and spa. This is also of interest to tourists who are able to participate
in a community-based bio-energy utilization system.
