Thermal Analysis and Optimization of a regenerator in a Solar Stirling engine

Thermal Analysis and Optimization of a Regenerator
in a Solar Stirling Engine
Rohith Jayaram, D Senthil Kumar
Department of Mechanical Engineering
Amrita Vishwa Vidyapeetham
Coimbatore, India
rohith.jayaraman@gmail.com,d_senthilkumar@cb.amrita.e
du
Divin P Xavier, Manikantan Ramaswamy
Department of Mechanical Engineering
Amrita Vishwa Vidyapeetham
Coimbatore, India
divin4303@gmail.com, manikantan93@gmail.com
Abstract— Stirling engine gains ground in the present
environment where there is a need for efficient, cheap and clean
energy. The Stirling engine forms a part of the power conversion
unit in the solar dish system, and it is critical to the electrical
output. The Stirling engine under consideration is a hermetically
sealed free piston engine, working on Stirling cycle with heat
source from solar thermal energy. The theoretical efficiency of a
Stirling engine is in agreement with the Carnot cycle efficiency;
however the performance in practice is less, caused by the
various irreversibilities affecting the engine. The various
irreversibilities occurring in the Stirling engine are attributed to:
conduction losses between the flowing fluid and heater and
cooler, flow frictional losses, and ineffectiveness of the
regenerator. Irreversibilities are mainly accounted by the
regenerative losses when compared with other contributing losses
which are negligible. This provides scope foroptimizing the
geometrical parameters of the regenerator so as to minimize
pressure losses in the regenerator, and to maximize regenerator
effectiveness. The most suitable material of the mesh matrix is
determined and analyzed on the basis thermal inertia effects.
The theoretical analysis is performed using second order
dynamic analysis, considering the effect of temperature
oscillations in the regenerator system.
Keywords— Stirling engine, Regenerator, Irreversibilities
I. INTRODUCTION
The Stirling engine is a closed cycle, regenerative, external
combustion engine which was invented in 1816 by Robert Stirling. It
has wide variety of applications such as in heating and cooling,
combined heat and power, solar power generation, Stirling
cryocoolers, heat pump, marine engines, nuclear power generation,
automotive engines, electric vehicles, aircraft engines and low
temperature difference engines. Its application has several
advantages like multi-fuel capability, low fuel consumption and low
noise. The variety of fuel sources (gases and liquids) and abundant
heat sources (solar, geothermal etc…) that can be used, make it
unique.
The Stirling engine’s working principle is based on Stirling cycle
which consists of 4 processes: Isothermal expansion, Isochoric heat
removal, Isothermal compression, Isochoric heat addition. [6]
Initially the hot, high pressure gas is expanded isothermally,
absorbing heat from the expansion space, thus doing work on the
power piston.The cold displacer piston then transfers the working gas
isochorically to the compression space through the regenerator,
where the heat is absorbed by the cold heat exchanger and stored by
the regenerator, thus lowering the temperature of the gas to Ta.
Fig. 1Simulation diagram of regenerator in a Stirling engine [15]
The power piston does work on the gas, compressing it isothermally
and rejecting heat to the compression space. In this process less work
is required for compressing the gas, as the gas is at a lower
temperature and pressure. Finally the warm displacer piston transfers
all the working gas isochorically to the expansion space through the
warm heat exchanger, where heat stored in the regenerator is
delivered to the gas, raising the temperature to TL and pressure of the
gas, before the next cycle begins with a new expansion. The heating
and cooling of the working gas is achieved by sending the working
gas back and forth through a serial connection of heat exchangers, i.e.
a cooler, regenerator and heater.
Stirling engines may be classified based on the heat exchanger
involved: Recuperative or Regenerative.[6]
Recuperative heat exchangers have separate flow passages for hot
and cold fluids. The heat is transferred by conduction across the
solidwall between the two streams which may flow continuously or
periodically. Regenerative heat exchangers contain void filled
porous matrix with a large heat transfer area and high heat capacity.
It acts as a thermal heat storage that minimizes the amount of energy
that must be added in the heater, thereby increasing the thermal
efficiency. Because the matrix alternately absorbs and releases
energy, the temperature profile of the matrix oscillates in time.
Regenerators have a large heat transfer area and are used in a cycle so
as to effectively increase heat transfer in the engine hence increasing
the power output and efficiency. Regenerator and its design is, thus,
central to the performance of Stirling engine. The performance of the
engine is affected by various losses in the regenerator.
International Journal of Applied Engineering Research, ISSN 0973-4562 Vol. 10 No.85 (2015)
© Research India Publications; http/www.ripublication.com/ijaer.htm
589

The various losses occurring in the regenerator include [10]:
 Regenerator Ineffectiveness Loss: Regenerator
ineffectiveness leads to higher temperatures within the
expansion space.
 Temperature Swing Loss: The shuttling of the working
fluid back and forth between the expansion and
compression space results in temperature loss within the
matrix medium.
 Pumping Loss/Fluid frictional loss: With greater
constrictions in the mesh matrix by virtue of parameters
like screen wire diameter, porosity results in reduction of
engine power output.
The regenerator loss can be minimized by reducing the temperature
difference between the gas and the matrix and also by increasing
theheat transfer area per unit volume. The heat transfer area can be
increased by reducing the wire diameter and/or by increasing the fill
factor but doing so will increase the flow resistance. Hence there is a
Pressure loss caused by flow resistance in the regenerator which in
turn causes a loss of power output from the engine.
A. Review of Engine Design Methods [11]
First orderdesign method is a simple method that relates the power
output and efficiency of the machine to the heater and cooler
temperature, the engine displacement and the speed. This method is
mainly for primary analysis and this analysis is also known as the
Schmidt analysis.
Second order engine design starts with the Schmidt analysis.
Various power losses are calculated and deducted from the Schmidt
power. Similarly various heat losses are calculated and added to the
Schmidt heat. All the engine processes are assumed to run parallel
and independent to each other.
Third order engine design deals with solving of the various
governing equations using differential equations by discretizing the
system into a number of nodes. The results are expected to be more
accurate while the process involved in solving is laborious at the
same time.
II. OBJECTIVE
An ideal Regenerator matrix geometry, as demonstrated by
Ackerman, possesses characteristics such as maximum heat transfer
area, minimum axial conduction, minimum pressure drop, minimum
dead volume. [11]. Thus this paper aims to perform a thermal
analysis and optimize the geometrical parameters of the regenerator
Nomenclatures
Ta Cold end Temperature (K)
TL Hot end temperature (K)
Kd Thermal conductivity of displacer wall (W/cmK)
Kmx Metal thermal conductivity of regenerator matrix (W/cmK)
Kg Thermal conductivity of fluid (W/cmK)
Kc Thermal conductivity of cylinder wall (W/cmK)
QL Heat absorbed (W)
Qa Heat released (W)
PL Low Pressure (MPa)
PH High Pressure (MPa)
Aht
ΔTmx
ΔTd
mf
BP
ρm
ΔP
λTc
λTd
h
Sd
Dcy
Cp
Cv
Agas
NTUv
Nr
Lr
Nz
R1R2,R3
L1,L2,L3
Area of heat transfer of regenerator matrix (cm2
)
Temperature swing of the regenerator matrix material (K)
Temperature gradient of displacer (K/cm)
Mass flow rate of fluid (g/s)
Brake power (W)
Mean density of fluid (g/cm3
)
Pressure drop (MPa)
Temperature wavelength for cylinder wall (cm-1
)
Temperature wavelength for displacer wall (cm-1
)
Heat transfer coefficient (W/cm2
K)
Stroke of displacer (cm)
Diameter of cylinder wall (cm)
Heat capacity of fluid at constant pressure (J/gK)
Heat capacity of fluid at constant volume (J/gK)
Displacer gap thickness (cm2
)
Number of heat transfer units assuming constant volume
Number of regenerators per power unit
Length of regenerator (cm)
Number of special nodes
Thermal resistance of section HB, BA, AC (K/W)
Length of section HB, BA, AC (cm)
Greek Symbols
 Porosity
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such as Wire diameter of the mesh screen, Porosity of mesh matrix,
Screen diameter, Material of the regenerator mesh matrix so as to
minimize the various losses affecting the efficiency of the Stirling
engine such as the fluid frictional losses, reheat loss, temperature
swing loss, shuttle conduction loss, conduction loss through
regenerator matrix and mechanical friction loss.
III. ENGINE SPECIFICATIONS
The Stirling engine considered for validation is GPU-3 model
developed by General Motors and its dimensions are shown below in
Table 1. The working fluid under consideration is Helium, operating
at a temperature range of 288K-977K.Even though, hydrogen has
better transport properties ( viscosity, density and thermal
conductivity) helium was preferred for the reason that usage of
hydrogen results in hydrogen embrittlement over the course of
operation The matrix materials are carefully chosen so that there is
maximum heat transfer between the regenerator material and working
fluid i.e. matrix materials with high specific heat capacity and low
thermal conductivity. Commonly used matrix materials are Iron and
stainless steel. The geometry of the regenerator mesh matrix
consideration is wire mesh as they were found to be produce less
entropy generation when compared to spherical balls and annular
type regenerator.
Table. 1Dimensions of GPU-3 Regenerator under consideration [11]
Parameters Dimensions
Housing length 22.6 mm
Housing internal diameter 22.6 mm
No. of regenerators per cylinder 8
Mesh Material Stainless Steel
Mesh Number 7.9 wires/mm
Wire diameter 0.04 mm
Number of layers 308
Porosity 70%
Screen to screen rotation 5˚
Break Power 4736W
IV. CALCULATION OF LOSSES
A. Flow friction loss
The energy loss happens in this case due to fluid friction, i.e. due to
friction, pressure losses occurring when the fluid passes through the
regenerator matrix. The flow friction inside a regenerator can be
computed by published correlations for fluid flow through porous
media and in tubes. These correlations are however applicable only
for steady, fully developed flow. The frictional loss (W) due to
pressure drop is given by [11]
.32f
friction
m
P m
Q

  

(1.1)
B. Reheat loss
The regenerator usually reheats the gas as it returns to the hot space.
But due to the inefficiency of the regenerator, extra heat is required at
the heat source. The reheat not supplied by the regenerator must be
supplied by the heater as extra heat input and thus leading to the
reheat loss. The Reheat loss (W) equation is given by [10],
2
.32 ( ) ( )
2
rh f v h c
v
Q m C T T
NTU
    
 (!.2)
Where,
ht
v
f v
h A
NTU
m C



The factor 0.32 multiplied, implies the fraction of the total cycle time
the gas is flowing into the hot space in the regenerator. This factor is
estimated by extrapolating the maximum flow to the hot space to the
total flow.
C. Conduction through Regenerator matrix
The regenerator usually consists of many layers of fine screens that
are lightly sintered. The degree of sintering has a considerable effect
on the thermal conductivity of the screens since the controlling
resistance is the contact between the adjacent screens. The heat loss
through an array of uniformly stacked cylinders (W) is given by [10],
( )
r mx ht
cond h c
r
N K A
Q T T
l
 
  (1.3)
D. Temperature swing loss
In some cases unlike reheat loss, temperature oscillations are not
negligible. These temperature oscillations occurring all along the
regenerator matrix, account for the temperature swing loss since a
temperature drop is observed along the temperature gradient line of
the matrix as the fluid flows through it. Hence the Heat loss due to
the temperature oscillations (W) is given by [10],
0.32
2
f v mx
ts
m C T
Q
  

(1.4)
E. Mechanical friction loss
Mechanical friction loss occurs due to the presence of seals and
bearings in the engine. The friction loss is measured directly by
having the engine operated at the design average pressure with a
large dead volume, so that very less engine action is possible. The
heat loss due to mechanical friction (W) is related to the Brake power
(W) and is given by the relation [11],
0.2mfQ BP  (1.5)
F. Shuttle Conduction loss
Shuttle conduction loss happens every time the displacer piston
oscillates across a temperature gradient. The displacer absorbs heat
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during hot end of its stroke and releases heat during cold end of its
stroke and this shuttling between the hot and cold end temperatures
along its gradient, result in heat loss. It is dependent on the wave
form of the motion and the Shuttle heat conduction loss (W) is given
by [10],
2
1
{ }
1 8
d g cy d
sh
gas
S K D TLB
Q
LB A
   
  

(1.6)
Where,
1
2
d cT Tg
gas d c
K
LB
A K K
 

 
   
  
G. Variable Thermal Conductivity losses
For 1-d heat conduction, where the heat transfer area as well as the
thermal conductivity varies continually, the heat conduction path is
divided into zones. The average heat conduction area for each zone
is calculated based on engine dimensions, temperature for each zone
is estimated and from this estimate a thermal conductivity is assigned
for each zone. The heat through each segment is considered same.
Fig. 2 Electrical equivalent model of thermal resistance network
Initially Ta and Tb are guessed to be at temperatures between Th and
TC and the conduction loss across the wall is given by,
1 2 3C
h cT T
Q
R R R


 
(1.7)
Using the conduction loss calculated, the temperatures Ta and Tb are
calculated as,
( 1 )
( 3 )
b h c
a c c
T T R Q
T T R Q
  
  
(1.8)
If the conductivity values at Ta and Tb are nearly same as the earlier
estimated conductivity then stop, if not repeat the process again.
H. Temperature Distribution Equations
Fig.3. Temperature distribution across an element of the matrix [11]
Based on the assumption mentioned above for the ideal regenerator,
matrix thermal equation turns out to be [11],
( ) ( )ps f m m
T
h A T T MC
t

    

(1.9)
Fluid thermal equation turns out to be
( ) ( ) 0i oQ W m e m e      (1.10)
The above is the conservation of energy equation for fluid. Based on
the assumption the conservation equation reduces to [11],
( ) ( )s f m f p
T
h A T T dx m C
x

      

(1.11)
Boundary conditions:
hT T Warm fluid entering the matrix
cT T cold fluid entering the matrix
Initial condition: Linear temperature distribution for the matrix
material
1
( )m w h
z
i
T T T Tc
N

   (1.12)
Where,
(1,2,3......,11)i 
V. RESULTS AND VALIDATION
A. Part A
The first part of the analysis includes plotting and studying the trend
of porosity against various losses and temperature distribution for the
material under consideration, Stainless Steel.
1) Trend of major losses against porosity
The trend in Figure 4 is obtained for the matrix material Stainless
Steel against porosity ranging from 0.60 to 0.85, considering the
following losses:
a) Flow frictional losses
Flow Frictional loss is inversely proportional to porosity and related
as follows [11],
3
frictionQ 

Hence the curve is a non-linearly decreasing one and accounts for the
maximum loss among all the losses, till a porosity value of 0.77 is
reached. A stable value of the loss is observed only after the porosity
reaches a value of 0.80.
b) Static conduction
Static conduction has a negligible effect on porosity and it almost
remains constant.
c) Reheat loss and the temperature swing loss
Both the losses increase with porosity, since the higher the porosity
is, more will be the temperature swing of the regenerator matrix.
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Fig. 4 Trend of major losses against porosity
2) Effect of porosity on temperature distribution inside
regenerator matrix
The porosity values are ranged from 0.60 to 0.85 and the
corresponding trend in Figure 5of temperature distribution along the
matrix, for the mesh material Stainless Steel is found out. The trend
shows that higher the porosity, the instantaneous slope of the curve
keeps increasing, thus implying the increase of temperature swing
loss.
As porosity increases the fill factor decreases[10].
(1 )fF  
This implies that the number of void spaces is increased and thus
resulting in reduction of regenerator mass. The regenerator mass
affects the total heat capacity of the mesh material and is directly
proportional [11].
0.32 ( )f v h c
mx
mx pm
m c T T
T
f M C
   
 
 
Hence the heat capacity is also reduced. This reduction in the heat
capacity of the mesh material adds to the inefficiency of the
regenerator as the heat is not entirely retained by the mesh in order to
be added to the fluid passing throughit. The reduced heat capacity of
the mesh material increases the temperature swing, thus resulting in
an increase in the temperature swing loss across the regenerator [eq.
1.4].
Fig. 5 Effect of porosity on temperature distribution
B. Part B
The second part of the analysis includes plotting and studying the
trends of porosity against various losses and temperature distribution
curves for various regenerator materials. A comparitative study was
carried out in order to obtain an optimum regenerator matrix material
for various losses considered.
The materials under consideration are:
 Stainless Steel
 Cr – Ni steel
 Inconel X-750
 Monel 400
 Fe
1) Effect of porosity on regenerator conduction losses for
various regenerator matrix materials
Regenerator matrix conduction loss (W) Vs Porosity
Porosity
0.55 0.60 0.65 0.70 0.75 0.80 0.85 0.90
Regeneratormatrixconductionloss(W)
25
30
35
40
45
50
55
60
SS
Cr-Ni Steel
Inconel X-750
Fe
Monel 400
Fig. 6 Effect of porosity on regenerator conduction loss
All the 5 materials display a downward trend in losses with increase
in porosity of the matrix as seen in Figure 6. This is because increase
in porosity results in increase in number of void spaces i.e. decrease
in fill factor, thus resulting in lower heat loss during conduction. In
addition to this, the similar trend followed by all the material is due to
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the dependence of heat conduction on a factor, thus contributing
nearly the same amount of conduction loss.
2) Effect of porosity on temperature swing loss for various
regenerator matrix materials
Temperature swing loss (W) Vs Porosity
Porosity
0.55 0.60 0.65 0.70 0.75 0.80 0.85 0.90
Temperatureswingloss(W)
20
40
60
80
100
120
140
160
SS
Cr-Ni Steel
Inconel X-750
Fe
Monel 400
Fig. 7 Effect of porosity on temperature swing loss
It is observed from Figure 7 that, as the porosity increases, the
temperature swing loss increases. This trend is observed since the
temperature swing is dependent on the thermal gradient established in
the regenerator matrix and is inversely proportional to the regenerator
mass. The regenerator mass is in turn is inversely proportional to
porosity. All materials considered show a similar gradually
increasing trend of losses as the porosity is varied from 0.60 to 0.85.
However the materials with higher density experience lesser
temperature swing loss. This is a result of density influencing the
regenerator mass which is inversely proportional to porosity.
Hence the preference order for selecting the optimum regenerator
material starting from lesser temperature swing loss based on the
trend observed, will be: Monel, Inconel X-750 > Fe, Cr – Ni steel >
Stainless Steel.
3) Effect of porosity on Brake thermal efficiency for
various regenerator matrix materials
From Figure 8 it can be inferred that for all the materials the brake
power efficiency increases and reaches a constant value as the
porosity increases. Inconel is found to have the maximum efficiency
with increasing porosity compared to other materials under
consideration. The reason for this is that materials with lower
thermal conductivities proved to exhibit lesser conduction losses
while performing the second order analysis of the Stirling engine.
Hence the preference order for selecting optimum material for the
regenerator matrix based on higher efficiency will be: Inconel > Cr-
Ni Steel > Monel 400> Stainless Steel> Fe.
Brake thermal efficiency Vs Porosity
Porosity
0.55 0.60 0.65 0.70 0.75 0.80 0.85 0.90
Efficiency
0.30
0.32
0.34
0.36
0.38
0.40
0.42
0.44
0.46
0.48
SS
Cr-Ni Steel
Inconel
Fe
Monel 400
Fig. 8 Effect of porosity on Brake power efficiency
4) Temperature distribution for various regenerator
matrix material
From Figure 9 it can be inferred that the alloy Inconel X-750 looses
heat faster due its poor thermal heat capacity as compared to
Stainless Steel. This instantaneous slope for Inconel X-750 implies
lower temperature gradient and consequently lower will be the
temperature swing. On the other hand, Stainless Steel with thermal
heat capacity of 1050 J/kgKlooses less heat and thus has a higher
temperature swing loss. Cr-Ni steel, Monel and Fe almost have the
same trend for the temperature distribution.
Grades of Stainless Steel are widely used as regenerator matrix
material in practical industrial applications, but Inconel X-750 will
give a better result with lesser temperature swing loss.
C. Part C
The third part of analysis includes results from trends of other
parameters under consideration such as wire diameter, screen
diameter and mesh density.
Fig. 9 Temperature distribution of various regenerator mesh materials
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1) Dependence of Porosity on Mesh density and Wire
diameter
Fig. 10 Dependence of porosity on mesh density and wire diameter
Figure 10shows the dependence of porosity on wire diameter and
mesh density. It is observed that Porosity is linearly proportional to
the mesh density and inversely proportional to wire diameter. The
interdependence of these parameters is evident from the relation
between Mesh density and wire diameter [11].
1
4
dw n

 
 
2) Effect of Screen diameter on Regenerator losses
Figure 11 shows the influence of screen diameter on matrix
conduction loss, frictional loss, temperature swing loss and reheats
loss. The graph depicts an upward trend where matrix conduction
loss is seen to linearly increase with the increase in matrix screen
diameter.This graph shows the influence of screen diameter on fluid
frictional loss. The graph depicts a downward trend where as
frictional loss is seen to linearly decrease with the increase in matrix
screen diameter. As per the above graph, temperature swing loss
varies inversely influence with the screen diameter. Temperature
swing loss reduces almost linearly with increase in screen diameter
and tends to a steady value after 30mm. This trend is observed
because of the direct influence of heat transfer area on screen
diameter [11],
2
ht rA D
Reheat loss has two different slopes; the one which has almost a
slope value of 90, and the slope from 22.2mm screen diameter which
has a linear trend. The proportionality is the same reason why the
trend influences the reheat loss.
Fig. 11 Effect of screen diameter on regenerator losses
VI. OPTIMIZATION
A. Porosity optimization
Fig. 12 Trend of efficiency against porosity
From Figure 12, the optimum value for the porosity is observed at
0.739, at which the efficiency is found to be 41.59%. Even though
the efficiency was found to increase with increase in porosity, the
porosity at 0.739 was considered best for the reason that losses were
determined to be minimum at that point where the input and output
characteristic losses intersect. This is evident from the trend
observed from Figure 14.
Losses Vs Screen diameter
Screen diameter(cm)
1.8 2.0 2.2 2.4 2.6 2.8
Losses(W)
0
50
100
150
200
250
300
Fluid frictional loss
Reheat loss
Temperature Swing loss
Regenerator matrix conduction
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Fig. 13 Trend of friction and other losses against porosity
B. Screen diameter optimization
Fig. 14 Trend of various Losses against Screen diameter
The Figure 14shows the variation of losses with mesh screen
diameter. The two trends show the variation of input and output
losses against the variation of screen diameter. It is found that
minimum losses were obtained at the point where input losses
(Reheat losses, Temperature swing loss and regenerator matrix
conduction loss) and output losses (Fluid friction losses) meet.This
point is found to be 24mm.
Table.2 Optimized results of the geometrical parameters
EFFICIENCYOPTIMIZED
VALUE
PARAMETERS
41.59%
0.043 mmWire diameter
73.9%Porosity
7.72(cm-1
)Mesh density
VII. VALIDATION
The validated comparison done in Table 3, considering all losses
brings an improvement in efficiency by 4.46% from the earlier
considered model [15], which had Stainless Steel as its regenerator
mesh matrix material and porosity and screen diameter values to be
70 and 22.4mm respectively. To obtain this efficiency, through
optimization process, the geometrical parameters were optimized to
have values: wire diameter 0.043mm, porosity 73.9%, mesh density
7.72cm-1
and screen diameter 24mm. In addition to these geometrical
parameters, through thermal analysis process, the optimum material
for regenerator matrix, in order to obtain the same efficiency was
found to be Inconel.
Table.3 Validation of results obtained
Thermal
efficiency(%
)
MATRIX
POROSITY(%)
/
Screen
diameter(mm)
REGENERATO
R MATERIAL
NUMERICA
L MODEL
52.570/ 22.4SSUrielli and
Berchowitz
model with
pressure drop
40.670/ 22.4SSDynamic
model
considering
conduction
losses
41.5973.9
(optimized) /
22.4
SS
44.72373.9 /22.4Inconel
45.0673.9 /24Inconel
VIII.CONCLUSION
The above validated comparison, considering all losses brings an
improvement in efficiency by 4.46% from the earlier considered
model which had Stainless Steel as its regenerator mesh matrix
material and porosity and screen diameter values to be 70 and 22.4cm
respectively. To obtain this efficiency, through optimization process,
the geometrical parameters were optimized to have values: wire
diameter 0.043mm, porosity 73.9%, mesh density 7.72cm-1
and
screen diameter 24mm. In addition to these geometrical parameters,
through thermal analysis process the optimum material for
regenerator matrix, in order to obtain the same efficiency was found
to be Inconel
IX. FUTURE WORK
The theoretical analysis done in this paper, in order to obtain
temperature distribution for various materials of the regenerator
matrix, was based on second order dynamic analysis. Through this
we were able to arrive at the optimum material for the mesh matrix.
However, this work can be carried out based on third order dynamic
analysis, which may be laborious as it involves solving the governing
equations, but one may be able to arrive at a higher accurate solution.
X. REFERENCES
1. Siegel, A. (2000, February). Experimental investigations on the
heat transfer behaviour of wire mesh regenerators in an
oscillating flow. In Proceedings of the European Stirling forum,
Osnabrück (pp. 139-47).
2. Costea, M., Petrescu, S., & Harman, C. (1999). The effect of
irreversibilities on solar Stirling engine cycle
performance. Energy conversion and management,40(15), 1723-
1731.
Losses(W) Vs Screen diameter
Screen diameter(cm)
1.8 2.0 2.2 2.4 2.6 2.8
Losses(W)
120
140
160
180
200
220
240
260
280
300
Fluid Frictional loss
Reheat loss+ Temp. Swing loss+Reg matrix conduction
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3. Fraser, P. R. (2008). Stirling Dish System Performance
Prediction model. University of Wisconsin – Madinson,
MASTER OF SCIENCE.
4. Gedeon D, W. J. (1996, February). Oscillating flow regenerator
test rig: hardware and theory with derived correlations for
screens and felts. NASA Contractor Report.
5. Gonzalez Bayon, J. (2009). Effect of dead space and
irreversibilities on the performance of the regenerator of a
Striling cycle engine. CIER.
6. Haywood, D. (n.d.). An Introduction to Stirling - Cycle
Machines. Stirling - Cycle Research group.
7. Isshiki S, T. Y. (1997, August). An experimental study on flow
resistance of regenerator wire meshesin oscillating flow. 32nd
Intersociety energy conversion engineering conference.
Honolulu.
8. Jones, J. D. (1986). Performance of a Stirling engine regenerator
having finite mass. Journal of engineering for gas turbines and
power, 108(4), 669-673.
9. L.S.Martins, J. J. (2012). Thermodynamic optimization of a
regenerator heat exchanger. El Savier.
10. Martini, W. R. (1978). Stirling Engine design manual. USA: US
Department of Energy.
11. Ozbay, S. (2011, August). Thermal Analysis of Stirling cycle
regenerators. The middle east technical university.
12. Andersen, S. K., Carlsen, H., & Thomsen, P. G. (2006).
Numerical study on optimal Stirling engine regenerator matrix
designs taking into account the effects of matrix temperature
oscillations. Energy Conversion and Management, 47(7), 894-
908.
13. Timoumi, Y., Tlili, I., & Nasrallah, S. B. (2008). Design and
performance optimization of GPU-3 Stirling
engines. Energy, 33(7), 1100-1114.
14. Tlili, I. (2012). Thermodynamic Study on Optimal solar Stirling
engine cycletaking into account the irreversibilities. Conference
on Advances in Energy Engineering.
15. Urieli, I., & Berchowitz, D. M. (1984). Stirling cycle engine
analysis. Taylor & Francis.
16. Zarinchang, J. (2009). Optimization of Thermal Components in
a a Stirling. Iran: Shiraz University.
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