JFK - Compressed Air Energy Storage (CAES)x - me258

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29 Νοε 2013 (πριν από 3 χρόνια και 6 μήνες)

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ME 258

Johann Karkheck


The ability to store energy has become a necessity due to the
intermittency of renewable energy sources that are gaining
presence on the grid.


Various technologies exist to accommodate a wide variety of
storage needs.



CAES is capable of high power output with long discharge
times.


Issues with CAES


Existing configurations are not very efficient


321 MW
Huntorf
, Germany ~ 42%


110 MW McIntosh, Alabama ~ 50%


Storage Vessel


Energy Losses



Modeled each system
component separately to
achieve a modular
layout








Analyze
different CAES configurations to achieve maximum
efficiency


Configuration 1


Single
-
stage
turbo machinery components with
polytropic

processes


Configuration 2


Double
-
stage compression and heat exchangers


Configuration 3


Triple
-
stage compression and heat exchangers


Configuration 4


Single
-
stage turbo machinery w/isentropic
compression/expansion and ideal motor and generator













Inter and after
-
cooling have the most detrimental effect on
system efficiency


The highest efficiency, 52
-
62% depending on heating and
cooling load, is achieved in a two
-
stage adiabatic CAES
configuration


If cooling is done via a natural source (i.e. river) an efficiency of
60% is realistic and would not require supplemental fuel


The key element to improve efficiency is development of a high
temperature thermal storage (>600
°
C) and temperature
resistant compressor materials








CAES can be implemented to
mitigate the intermittency of
renewable energy sources


Thermal energy storage
coupled with CAES eliminates
the need for fossil fuel in
reheating


Evaluate the effect of thermal
storage on the efficiency of
CAES using thermodynamic
modeling



Initial parameters were used
to study the effect of thermal
storage on CAES


Inlet temperature of
compressor and expander has
greatest effect on thermal and
power efficiency



The ratio of high storage
pressure to the ambient
pressure effects all work and
heat transfer parameters


Number of charge/discharge
cycles does not effect these
parameters


Selection of appropriate
pressure limits can raise power
and thermal efficiency




Charge and discharge processes induce
fluctuations in the pressure and
temperature within the storage cavern



Predictions of these fluctuations are
required for proper cavern design and
selection of turbo
-
machinery



Numerical and approximate analytical
solutions were used to model the T&P of
the air cavern



Sensitivity analysis was conducted to
determine the dominant parameters that
affect the T&P fluctuations and the
required storage volume.



Heat transfer through cavern walls
greatly effects T&P variations



Preference should be given to
caverns with high rock
effusivity





Losses can be reduced through
reducing the injected air
temperature



Longer durations of charge and
discharge can also aid in reducing
losses



Numerical modeling was performed on coupled thermodynamic,
multiphase fluid flow and heat transfer associated with CAES in
lined rock caverns



Using concrete lined caverns at a relatively shallow depth can
reduce construction and operational costs if air tightness and
stability can be assured




Numerical modeling was
performed on coupled
thermodynamic,
multiphase fluid flow and
heat transfer associated
with CAES in lined rock
caverns



Using concrete lined
caverns at a relatively
shallow depth can reduce
construction and
operational costs if air
tightness and stability can
be assured




Models of both tight and
leaky caverns show that the
leakage rate increases over
time resulting in increasing gas
saturation of the lining and
cavern wall




Leaky storage

caverns
continue to diminish the
achievable storage pressure
over time




Use of lined rock caverns at a shallow depth is only feasible if air
tightness and stability can be assured



The key parameter to assure long term air tightness is the
permeability of the concrete and surrounding rock



Increasing the moisture content of the lining can also decrease air
leakage



Keeping the injection temperature close to the ambient cavern
temperature can nearly eliminate thermal losses through the cavern
walls






To avoid the deterioration of the
cavern over time, configurations of a
constant pressure water
-
compensated
CAES system was studied



The constant pressure system with a
compensating water column requires a
very deep air storage cavern to
produce the required pressure,
resulting in high construction costs



Using a hydraulic pump rather than
elevation difference reduces
necessary storage depth, but the
pump consumes approximately 15%
of the generated power



Coupled compressed air and
hydraulic storage tanks allow the
compressed air to remain at constant
pressure and energy to be produced
by both CAES and hydraulic storage



System is independent of storage
depth



Exergy

loss of the air in
hydraulic storage during discharge
can be reduced by spraying water
into the air to achieve a quasi
-
isothermal process



Thermal storage improves CAES system efficiency and can
negate the need for supplemental fuel during expansion


Research is needed to find high temperature (>600
°
C) thermal
storage and compressor materials


Keeping the cavern inlet temperature near the storage
temperature reduces losses due to heat transfer


Air tightness of storage cavern is essential to retain long term
system efficiency



CAES coupled with hydraulic storage can make the depth of
the storage cavern irrelevant and improve start up time of
discharge cycle


1. The
thermodynamic effect of thermal energy storage on compressed air energy storage system

Zhang, Yuan (Institute of Engineering
Thermophysics
, Chinese Academy of Sciences, Beijing 100190, China); Yang,
Ke
; Li,
Xuemei
;
Xu
,
Jianzhong

Source:

Renewable Energy
, v 50, p 227
-
235, February 2013

Database:

Compendex


2. Operating
characteristics of constant
-
pressure compressed air energy storage (CAES) system combined with
pumped hydro storage based on energy and
exergy

analysis

Kim, Y.M. (ECO Machinery Division, Korea Institute of Machinery and Materials, 171 Jang
-
dong,
Yuseong
-
gu
,
Daejeon

305
-
343, Korea, Republic of); Shin, D.G.;
Favrat
, D.
Source:

Energy
, v 36, n 10, p 6220
-
6233, October 2011

Database:

Compendex


3. Exploring
the concept of compressed air energy storage (CAES) in lined rock caverns at shallow depth: A
modeling study of air tightness and energy balance

Kim,
Hyung
-
Mok

(Korea Institute of Geoscience and Mineral Resources (KIGAM),
Daejeon

305
-
350, Korea, Republic of);
Rutqvist
, Jonny;
Ryu
, Dong
-
Woo; Choi,
Byung
-
Hee
;
Sunwoo
,
Choon
; Song, Won
-
Kyong

Source:

Applied Energy
, v 92, p
653
-
667, April 2012

Database:

Compendex

4. Temperature
and pressure variations within compressed air energy storage caverns

Kushnir
, R. (School of Mechanical Engineering, Tel Aviv University, Tel Aviv 69978, Israel); Dayan, A.;
Ullmann
, A.
Source:

International Journal of Heat and Mass Transfer
, v 55, n 21
-
22, p 5616
-
5630, October 2012

Database:

Compendex



5. Simulation
and analysis of different adiabatic Compressed Air Energy Storage plant configurations

Hartmann,
Niklas

(University of Stuttgart, Institute of Energy Economics and the Rational Use of Energy (IER),
Hebrühlstr
.
49a, 70565 Stuttgart, Germany);
Vöhringer
, O.;
Kruck
, C.;
Eltrop
, L.
Source:

Applied Energy
, v 93, p 541
-
548, May 2012

Database:

Compendex