Low- and medium-temperature deep geothermal
energy is utilized in various countries for combined
heat and power generation (CHP). In addition, due to
the heat island effect and the higher requirements about
thermal wellbeing, the cooling demand is expected to
significantly increase within the future. In contrast to
electricity-intensive vapour compression cycles,
absorption chillers driven by geothermal energy are a
promising environmentally friendly alternative for
cooling purposes. Therefore, geothermal trigeneration
systems that can provide cooling, heating and power
generation by an Organic Rankine Cycle (ORC) will be
of high interest in the future.
While there is a strong research focus on advanced
ORC CHP concepts for geothermal applications, the
investigation of efficient and flexible geothermal
trigeneration systems is still at an early stage and so far
only a few potential concepts were evaluated. In
addition, most of the existing studies consider only
rather simple ORC models and neglect the part-load
behaviour due to changing cooling and heating
demands. This paper evaluates the performance of
several trigeneration arrangements. A special focus is
laid on different plant architectures and their part-load
behaviour as well as the optimal integration of different
absorption chiller types. The results provide valuable
insights on the most promising trigeneration system
concepts for different geothermal heat source
temperatures and demand profiles.
For assumed heat source conditions of 130 kg/s and
130 °C, the results reveal that an advanced serialparallel
configuration provides the highest net power
output over the year, followed by a serial configuration
with the absorption chiller on the third position and a
standard serial-parallel configuration. Considering the
part-load behaviour and the optimal absorption chiller
integration can have a significant impact on the
achievable plant power output. Thus, a meaningful
comparison of different systems with varying heating
and cooling demands requires the consideration of both
the absorption chiller integration and the part-load
behavior.
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Low- and medium-temperature deep geothermal
energy is utilized in various countries for combined
heat and power generation (CHP). In addition, due to
the heat island effect and the higher requirements about
thermal wellbeing, the cooling demand is expected to
significantly increase within the future. In contrast to
electricity-intensive vapour compression cycles,
absorption chillers driven by geothermal energy are a
promising environmentally friendly alternative for
cooling purposes. Th...
»