entropy
Article
Exergy and Exergoeconomic Analysis of a
Cogeneration Hybrid Solar Organic Rankine Cycle
with Ejector
Bourhan Tashtoush 1, Tatiana Morosuk 2,* and Jigar Chudasama 2
1Mechanical Engineering Department, Jordan University of Science and Technology, Irbid 22110, Jordan;
2Institute for Energy Engineering, Technische Universität Berlin, Marchstr. 18, 10587 Berlin, Germany;
*Correspondence: tetyana.mor[email protected]
Received: 28 May 2020; Accepted: 17 June 2020; Published: 24 June 2020
Abstract:
Solar energy is utilized in a combined ejector refrigeration system with an organic Rankine
cycle (ORC) to produce a cooling effect and generate electrical power. This study aims at increasing
the utilized share of the collected solar thermal energy by inserting an ORC into the system. As the
ejector refrigeration cycle reaches its maximum coefficient of performance (COP), the ORC starts
working and generating electrical power. This electricity is used to run the circulating pumps and the
control system, which makes the system autonomous. For the ejector refrigeration system, R134a
refrigerant is selected as the working fluid for its performance characteristics and environmentally
friendly nature. The COP of 0.53 was obtained for the ejector refrigeration cycle. The combined cycle
of the solar ejector refrigeration and ORC is modeled in EBSILON Professional. Different parameters
like generator temperature and pressure, condenser temperature and pressure, and entrainment ratio
are studied, and the effect of these parameters on the cycle COP is investigated. Exergy, economic,
and exergoeconomic analyses of the hybrid system are carried out to identify the thermodynamic
and cost inefficiencies present in various components of the system.
Keywords:
exergy analysis; economic analysis; exergoeconomic analysis; ejector refrigeration cycle;
organic Rankine cycle
1. Introduction
The conventional vapor-compression refrigeration system (VCRS), which uses working fluids that
are harmful to the environment, is dominating in the refrigeration sector all over the world. The solar
ejector refrigeration system (SERS), which uses solar energy as the driving energy, is the alternative for
VCRS. Thus, it helps to decrease the indirect environmental impact though reducing the CO
2
emissions
coming from electricity generation. The maintenance cost required of the ejector refrigeration system
(ERS) is meager [
1
]. Solar energy is the most abundant, vast, and inexhaustible source of energy for
a clean environment. Researchers have started investigating the replacement of high-priced fossil
fuels with alternative renewable energy sources such as wind, solar, and geothermal. As the supply of
solar energy is highly compatible with the demand, the use and implementation of solar energy in air
conditioning and refrigeration applications have gained more attention over the last decades.
The conventional solar cooling and refrigeration cycles include sorption machines such as
adsorption and absorption machines, or desiccant wheels. Furthermore, SERS is competitive with the
mentioned technologies as they have lower cost, no moving parts, simple system design, and can be
driven by low-grade thermal sources [1,2]. The solar energy can be used to drive an organic Rankine
Entropy 2020,22, 702; doi:10.3390/e22060702 www.mdpi.com/journal/entropy
Entropy 2020,22, 702 2 of 19
cycle (ORC) to generate electrical power [
3
–
5
]. Combined cycles and systems were proposed by several
researchers to maximize the utilization of wasted heat and renewable energy and reduce fossil fuel
consumption to alleviate environmental problems [6].
Many researchers have investigated the combined ERS with ORC for the production of cold and
power [
7
–
9
]. Li et al. [
10
] proposed an ORC with an ejector (EORC) to increase the power output
capacity and cycle efficiency. Exergy and energy analyses of the combined cycles were carried out,
and it was found that the heat addition process had the maximum irreversibility, followed by the
ejector and turbine [
11
,
12
]. The ejector performance under the critical mode of operation and an hourly
dynamic simulation of the SERS of 7 kW refrigeration capacity was developed using TRNSYS Software
coupled with EES (Engineering Equation Solver) [13,14].
An ejector is a device used to suck the vapor from the vessel or framework. The real distinction
between the ejector and the vacuum pump or compressor is that it had no moving parts. Hence, it
is relatively cheap and easy to operate and almost free to maintain equipment. The primary nozzle
location (PNL) determines the type of ejector in terms of constant pressure mixing (CPM) or constant
area mixing (CAM). If the PNL is in the downstream location of the suction chamber, then it is a CPM,
while if the PNL is in the constant area section, the ejector is CAM. The performance of the CPM ejectors
is better than that of the CAM ejector [
15
]. The main advantages of using ejectors in the systems are no
moving parts; minimal to zero maintenance; robust construction; safe to install and upgrade; operates
on gas, liquid, and multi-phase; low cost; minimal control and instrumentation; and lower weight.
The ejector was introduced into the VCRS to enhance the system performance and increase its
coefficient of performance (COP) [
16
]. In another work, researchers presented a thermodynamic
analysis of an ejector cascade cooling cycle for low and medium temperatures [
17
,
18
]. In addition, the
implementation of new technologies and cycle modifications was introduced to improve the cycle
performance. Mathematical and thermodynamic models of the integrated Rankine power cycle into
the ERS were performed to estimate the effect of key parameters on the system performance [19–21].
ORC is implemented to produce power from low and medium grade heat sources when the
temperature is in the range of 80 to 350
◦
C. The low-grade heat that could be wasted can be utilized
and recovered in these technologies [
22
]. The circulated organic fluid in the ORC is selected for the best
accommodation of the heat source based on their thermodynamic properties to achieve the highest
cycle efficiency.
ORC systems are used to harvest low-grade waste heat and, therefore, increase the overall thermal
efficiency of the system. The low-grade heat is transformed into useful work in the form of electricity.
Simulation of organic Rankine cycle is carried out in EBSILON Professional Software [23].
One of the factors affecting the cycle performance is the working fluid and its thermal and physical
properties. The selection processes of the best environmentally friendly working fluid for ORC and
ERC cycles were studied by several authors [
24
,
25
]. The environment friendly refrigerants that have
the best performance characteristics with lower global warming and ozone depletion impacts on the
environment were found to be R600, R134a, and R1234yf.
Exergy is the theoretical maximum work that could be obtained in terms of either the shaft or
electrical work from an energy system when it is brought into thermodynamic equilibrium with the
environment [
26
]. It measures how different is the actual state of a system in comparison with the
environment, which is in thermodynamic equilibrium with total exergy equal to zero, and with no
irreversibility. The exergetic performance of the ORC combined with an ERC was thermodynamically
studied for the use of a low-grade heat source [
27
,
28
]. The results indicated that the losses and
destruction in exergy were the highest in the boiler and the lowest in the expansion valve, and the
efficiency was better in the case of a low critical temperature working fluid. Other works studied in
detail the combined ERS and ORC, which could recycle the waste heat for power and refrigeration,
and compared it with the conventional cycle [
29
,
30
]. The costs that the owners and/or investors must
recover include, but are not limited to preliminary feasibility and engineering studies, development
costs, environmental studies, legal fees, taxes, and electrical interconnection costs [
31
,
32
]. The efficiency
Entropy 2020,22, 702 3 of 19
of the ejector components significantly affects the exergy destruction within the components as well as
in other components [33,34].
Extensive research works were conducted on the combined cycles’ configuration and economic
optimization. The research work concluded that combined cycles for trigeneration of cold, heat, and
power with wasted or low-grade heat were efficient [
35
–
37
]. New combined ERS with ORC were
studied, and it was found that the power needed to drive the compressor could be decreased, and the
system COP increased [38].
Different types and configurations of air conditioning and refrigeration systems are used in
industrial, residential, and commercial applications to maintain comfort conditions. In the case of the
application of these systems in places and areas without reliable power supply, the low-grade heat
source can be utilized in refrigerating machines, which makes them promising technologies. It has
been found in the literature that the ERC has a maximum COP at an optimum generator temperature.
In addition, owing to the dynamic behavior of the solar radiation and its variation during the day,
the amount of energy utilized by ERC is much less than the total energy harvested. Therefore, in this
study, a new configuration ERC configuration combined with an ORC is presented to maximize the
use of the collected solar energy and increase the total thermal efficiency of the system. A hybrid
autonomous SERS combined with an ORC to produce a refrigeration effect and power is investigated.
The ERC is modeled in Engineering Equation Solver Software (EES), and the results were used to model
the entire cycle in EBSILON Professional. The ERC refrigeration capacity is 10.75 kW, and the rated
power output of the ORC is 0.76 kW. It is intended to maximize the harvesting of the collected solar
energy by introducing the ORC into the system so that the ERS utilizes its need from the solar energy
collected, and the excess energy will be used in the ORC to produce electrical power. This electricity
could be used to power the pumps and the system’s control unit and, therefore, make the system
autonomous. A parametric study of the operating conditions’ effect on the cycle performance an exergy
study is carried out to evaluate the real thermodynamics inefficiencies within the system. The exergy
efficiency and exergy destruction values of the system components are evaluated. The approach of
exergoeconomic analysis is used to find the comparative cost importance for each component in the
system. It takes into consideration not only the bare module cost, fuel, and operation and maintenance
cost (OMC), but also the cost of the exergy destruction within the component. The total revenue
requirement (TRR) method is used as a basis for an economic analysis of the system.
2. System Overview and Description
The ERS mainly consists of five components: generator, condenser, evaporator, ejector, and the
expansion valve. Here, the roles of the turbine and compressor are replaced by the ejector that has no
moving parts. The entire system can produce a refrigeration effect using waste heat or solar energy.
As shown in Figure 1a, the solar energy is used in the generator to heat the primary flow (Process 3–4).
This primary flow continues to flow through the converging-diverging nozzle in the ejector, where it
gains speed. The high-speed flow creates a reduction in the pressure and induces a secondary flow to
the ejector from the evaporator. The primary and secondary streams combine in the mixing chamber
and enter the diffuser. The pressure increases to the condenser pressure and enters the condenser,
where the vapor condenses into a liquid. The refrigerant liquid is divided into two streams; one is
pumped to the generator, and the other portion is directed to the expansion valve. The refrigerant
expands to the evaporator pressure and evaporates, producing the refrigeration effect, and the vapor
from the evaporator is sent to the ejector to complete the cycle.
Entropy 2020,22, 702 4 of 19
Entropy2020,21,x4of20
(a)
(b)
(c)
Figure1.(a)Thehybridsolarejectorrefrigerationcycle(SERC)withorganicRankinecycle
(ORC),(b)thelgp‐hdiagramoftheERC,and(c)thelgp‐hdiagramoftheORC.
Fromthesolarcollector,theaccumulatedenergyinthestoragetankisfurthertransferredtothe
generator.Theworkingfluidinthegeneratorgetsheatedupandvaporized,andthesameprocess
continuesintheERS.
3.Methods
3.1.EnergyAnalysis
TheERSismodeledinEES,andacomputerprogramisdevelopedbasedonthemass,
momentum,andenergyconservationprinciples.Theenergybalancesareasfollows:
Fortheevaporator:
Forthegenerator:
Forthecondenser:
𝑄𝑚ℎℎ(1)
𝑄𝑚ℎℎ(2)
Figure 1.
(
a
) The hybrid solar ejector refrigeration cycle (SERC) with organic Rankine cycle (ORC),
(b) the lg p-h diagram of the ERC, and (c) the lg p-h diagram of the ORC.
From the solar collector, the accumulated energy in the storage tank is further transferred to the
generator. The working fluid in the generator gets heated up and vaporized, and the same process
continues in the ERS.
3. Methods
3.1. Energy Analysis
The ERS is modeled in EES, and a computer program is developed based on the mass, momentum,
and energy conservation principles. The energy balances are as follows:
For the evaporator: .
Qe=.
me(h7−h6)(1)
For the generator: .
Qg=.
mg(h4−h3)(2)
For the condenser: .
Qc=.
mp+.
ms(h8−h1)(3)
For the ejector
(.
mp+.
ms)h8=h4
.
mp+h7
.
ms(4)
Entropy 2020,22, 702 5 of 19
The throttling process is as follows:
h5=h6(5)
The pump power is as follows: .
Wp=.
mp(h3−h2)(6)
The performance of the ERS is given by COP as follows:
COP =.
Qe/.
Qg+.
Wpump(7)
The following assumptions were considered in the modeling process of the cycle:
•Flow-through, the ejector, is 1-D, adiabatic, and steady;
•Isentropic flow through diffuser and nozzle;
•
CPM ejectors are used because they generate higher condenser pressures than ejectors of CAM
with similar COP and entrainment ratios;
•Generator pressure and temperature are 33 bar and 90 ◦C, respectively;
•Evaporator pressure and temperature are 4.5 bar and 12.45 ◦C, respectively;
•The throat diameter of the ejector is 0.000605 m.
The thermodynamic model of the ejector is presented in the flow chart given in Figure 2.
Several values of pressure and temperature of the generator and evaporator were used in the simulation
program. The effect of variation of these parameters on the ERC performance was studied.
3.2. Exergy Analysis
The energy balance is mainly concerned with the energy quantity, and it does not account for the
quality of energy. In thermodynamics, the quality of a given quantity of energy is characterized by its
exergy [24].
Exergy analysis is performed as an extension of energy analysis. It is useful because it provides a
more accurate and more robust analysis of thermodynamic systems than an energy analysis. Besides,
it accounts for the useful energy of an energy stream or the part of energy in an energy stream capable
of performing work. Energy analysis merely gives a gross sum of energy regardless of its usefulness.
Exergy analysis can be performed on a system level, subsystem level, or component level. Each case
provides different information that is useful for system optimization.
In a thermodynamic system, the real inefficiencies are the exergy destruction occurring within
the system boundaries and the exergy transferred to the surrounding system (exergy losses). Some of
the causes of exergy destruction are a chemical reaction, fluid friction, throttling of flow, mixing of
dissimilar flow, and heat transfer through finite temperature difference. The total exergy of the system
consists mainly of four components: chemical, physical, potential, and kinetic exergy. The physical
exergy is further considered, and all other forms are neglected. The temperature T
0
is 298.15 K and
pressure p0is 1.013 bar for the reference environment in this analysis.
Entropy 2020,22, 702 6 of 19
Entropy2020,21,x6of20
Figure2.Theejectormathematicalmodelflowchart.
1/ 1
2
1
p
primary generator t
generator
mPA
TR
2
2
2
1/ 1
2
1
1
1
/1
1
1
12 1
1
12
1
12
p
p
tp
generator
p
p
AM
AM
PM
P
2
/1
1
12
evaporator
sy
sy
PM
P
2
2
2
2
/1
1
/1
1
1/ 1
1/ 1
111
11/2
11/2
/2/111/2
1/ 2/ 1 1 1 /2
p
py
ppy
ppy py
py
ppp
M
P
PM
MM
A
AMM
3
p
ysyAA A
2
2
1
12
1
12
evaporator
s
y
sy
generator
p
y
py
T
M
T
TM
T
1/ 1
2
1
evaporator sy
s
s
evaporator
PA
mR
T
,
,
p
ypypypy py
s
ysysysy py
VMaa RT
VMaa RT
Fpy sy
primary secondary primary secondary FmmVmVmV
22 2
22 2
,
primary secondar
py sy
y primary secon
F
ppy psy pF
F
FF sy
y
F
dar
VV V
CT CT CT
V
MaRT
mm m
a
m
32
2
32
2
11
1
2
11/2
1/2
F
F
F
F
PM
P
M
MM
/1
42
3
3
1
12
PM
P
P
4
≤ P
critical
P
critical
Yes
No
26
15
condenser
r
evaporator
evaporator
gene
se
r
condary
prim
t
a
ao
r
r
y
P
CP
hh
COP
m
hh
m
1
g
enerator generator generatorPP P
p
rimarym
,,1t generator generatorAT P
1
p
A
1, 1
p
p
P
M
,evaporator evaporatorPT
s
y
P
,
p
ypy
M
P
s
yA
s
econdary
m
,
s
ypyTT
,
s
ypyVV
F
V
*
F
py sy syPPPP
,
F
F
M
T
3, 3
P
M
4
P
Figure 2. The ejector mathematical model flow chart.
The exergy calculations were performed on a streaming basis and then on a component basis
using the data from EBSILON Professional. The stream basis gives an overview of the exergy carried
by each stream. The fuel and product methods are used for the components’ exergy balance and
estimation of exergy destruction.
.
EF,tot =.
EP,tot +.
ED,tot +.
EL,tot (8)
Entropy 2020,22, 702 7 of 19
The rate of exergy loss is not considered for individual components, therefore,
.
EF,k=.
EP,k+.
ED,k(9)
Exergetic efficiency εkis calculated by the rate of exergy of product and exergy of fuel
εk=
.
EP,k
.
EF,k
(10)
Overall system exergy efficiency εtot
εtot =
.
EP,tot
.
EF,tot
(11)
The exergy destruction ratio y∗
D,k
y∗
D,k=
.
ED,k
.
ED,tot
(12)
There are some components in the system known as dissipative components, such as the throttling
valve and condenser. In these components, exergy is destroyed or transferred into the environment
without obtaining the positive exergetic effect. No exergetic efficiency can be defined for these
components. Only the thermodynamic inefficiency should be calculated for each dissipative component
.
Ek,dissipative =.
Ein,k+.
Eout,k(13)
3.3. Economic Analysis
The performance characteristics and operating costs are essential for the competitiveness and
economic feasibility of a project. The increasing awareness among consumers, regarding health and
climate change, leads to social acceptance becoming increasingly crucial for the smooth commissioning
of a new system. This acceptance requires the projects to be as efficient and environmentally friendly
as possible without becoming exceedingly expensive. Investors have to plan, design meticulously,
and analyze the system they want to build and ensure a sound technical efficiency as well as a profitable
return on the investment.
For economic analysis, the TRR method for a system is used. The annual system TRR is the
annual collected revenue that ensures the compensation of the system operating costs and ascertains
the economical operation of the plant. The levelized TRR is the addition of carrying charges (CC
L
) and
the expenses of fuel and operation and maintenance costs (FCL) and (OMCL), respectively.
TRRL=CCL+FCL+OMCL(14)
The CC
L
is the capital investment cost, which includes total capital recovery, preferred stock, return
on investment for debt, income taxes, and other taxes and insurances. Expenses are mainly FC
L
and
OMC
L
. The CC
L
is the levelized value of the total capital investment cost (TCI), which is composed of
the fixed capital investment (FCI) plus the interest to be paid for the investment.
TCI =FCI +interest (15)
The FCI is calculated by adding the cost of the bare module cost (BMC) to the service facilities,
architectural work, and contingencies. The FCI would represent the total system cost if it had a zero-time
design and construction period. The indirect system costs are construction costs, contingencies,
administrative fees, and engineering.
FCI =BMCtot +service facilities +architechtural work +comntigencies (16)
Entropy 2020,22, 702 8 of 19
The first step in the estimation of TCI was to estimate the purchase equipment cost (PEC) using
graphs, cost functions, or market research. The second step in the estimation was to adjust the purchase
equipment cost for the required size using the power law as follows:
CPE,new =CPE,known Xnew
Xknown !α
(17)
where
CPE,new
is the approximate equipment costs having the size
Xnew
,
CPE,known
is the known
equipment costs having the corresponding size
Xknown
, and
α
is the size exponent. The dimensionless
size exponent αcan be found, for example, in [24].
Different methods of cost estimation are based on empirical data. Usually, the values are calculated
for a specific year of reference and adapted to the year of analysis using the chemical engineering plant
cost index (CEPCI) factors [
33
]. The third step is to update the estimated equipment cost
CPE,new
to the
reference year. The reference year is chosen as 2018, with CEPCI equal to 603.1.
CPE,ref =CPE,old CEPCIre f
CEPCIold !(18)
where subscript ref refers to the year the equipment is supposed to be purchased and subscript old
refers to the year the cost of equipment was valid.
After calculating the current proportionated equipment purchase cost, the particular nature and
characteristics of the equipment have to be considered in the form of factors. For unique materials,
high pressures, and distinctive designs, the materials and pressure correction factors (MPF) were defined.
It can be a function of design variation (subscript d), pressure variation (subscript p), construction
material variation (subscript m), and operational limits (subscript o). The way of calculating the MPF
and variations that are considered depend on the equipment. The final step in the cost estimation
method was to account for the installation costs using the module factor (MF). The MF takes into
account labor, piping instruments, accessories, and everything necessary for installing the equipment.
A typical value for the MF is 2.95. The final BMC can be calculated with the following equation:
BMC =CPE,ref,new(MPF +MF −1)(19)
The total direct costs were calculated as the sum of BMC, whereas the indirect costs were calculated
as a percentage of the total direct costs. In order to get the TCI, the other outlays had to be considered
together with the FCI. The other outlays consisted of the allowance for funds used during construction,
which considered the time value of money and the interest that occurred during the construction
period and had to be repaid.
Having calculated the total amount of money that would be invested, the system’s economic life,
the interest rate, the average inflation, and the average nominal escalation rate of the fuel had to be
considered. These inputs were used to calculate the constant escalation levelization factors (CELF) and
the capital recovery factor (CRF) to perform a detailed cost calculation.
CRF =ief f 1+ie f f n
1+ief f n−1
(20)
ief f is the effective interest rate, and nis the economic lifetime.
FCLis determined as follows:
FCL=FC0∗CELF =FC0∗
kFC1−kn
FC
1−kFC
∗CRF (21)
Entropy 2020,22, 702 9 of 19
and
OMCL=OMC0∗CELF =OMC0∗
kOMC1−kn
OMC
1−kOMC
∗CRF (22)
with
kFC =1+rFC
1+ief f
and
kOMC =1+rOMC
1+ief f
, where
rFC
is the average inflation rate of the fuel cost and
rOMC
is the operating and maintenance cost.
FC0
is the first-year fuel cost, and CELF is the constant
escalation levelization factor.
3.4. Exergoeconomic Analysis
Exergoeconomic analysis is a combination of exergy and costs analyses to present to the designer
or the operator of an energy conversion system with the information not available through conventional
energy, exergy, or cost analysis. This approach of exergoeconomic is used to find the comparative
cost importance for each component in the system. The information obtained through exergy and
economic analyses are combined to determine the cost of each stream in the system. The main aim is
to create a cost balance of each component in the system.
For each component of the system,
.
CP,k=.
CF,k+.
Zk(23a)
cP
.
EP,k=cF
.
EF,k+.
Zk(23b)
where the average component cost of fuel
cF=
.
CF,k
.
EF,k
and product
cP=
.
CP,k
.
EP,k
, and the exergy destruction
cost rates within the component, .
CD,k=cF
.
ED,k(24)
For the overall system, .
CP,tot =.
CF,tot +.
Ztot −
.
CL,tot (25a)
cP,tot
.
EP,tot =cF,tot
.
EF,tot +.
Ztot −
.
CL,tot (25b)
where the average total cost of fuel
cF,tot =
.
CF,tot
.
EF,tot
and product
cP,tot =
.
CP,tot
.
EP,tot
, and the exergy destruction
cost rates within the component, .
CD,tot =cF,tot X.
ED,k(26)
Exergoeconomic factor f
k
indicates the relative contribution of the exergy destruction cost rate and
those associated with the CC
L
and OMC. This factor is used during the optimization to make decisions
of whether to invest in a more efficient component to reduce the exergy destruction or to sacrifice
efficiency to decrease the cost rate associated with the carrying charges.
fk=
.
Zk
.
Zk+.
CD,k
(27)
4. Results and Discussion
The entire system cycle represents the combination of the SERC with the ORC, where solar energy
is used to drive both cycles for cogeneration of cooling capacity and electrical power. The simulation
of the ERC and ORC was carried out individually, and later, the solar subsystem, which includes solar
collectors and hot storage tank, was added to the primary cycle, and the whole cycle was designed in
EBSILON Professional.
The assumptions used for the solar subsystem are that the solar collector is an evacuated tube
collector (50 m
2
), outlet temperature of collector =111.1
◦
C, maximum storage capacity =2000 kg,
Entropy 2020,22, 702 10 of 19
storage volume =2 m
3
, storage pressure =10 bar, average storage temperature =110
◦
C, and direct
normal irradiation (DNI) =1100 W/m2.
The obtained values of the thermodynamic parameters for the SERC and organic Rankine cycle
are shown in Figure 3. After having the results of all the parameters of the ejector refrigeration cycle
in the EES, it is further modeled in EBSILON Professional Software. The results show an excellent
agreement with those data obtained from the EES. The refrigeration capacity of the ejector refrigeration
cycle is 10.75 kW.
Entropy2020,21,x10of20
TheentiresystemcyclerepresentsthecombinationoftheSERCwiththeORC,wheresolar
energyisusedtodrivebothcyclesforcogenerationofcoolingcapacityandelectricalpower.The
simulationoftheERCandORCwascarriedoutindividually,andlater,thesolarsubsystem,which
includessolarcollectorsandhotstoragetank,wasaddedtotheprimarycycle,andthewholecycle
wasdesignedinEBSILONProfessional.
Theassumptionsusedforthesolarsubsystemarethatthesolarcollectorisanevacuatedtube
collector(50m2),outlettemperatureofcollector=111.1C,maximumstoragecapacity=2000kg,
storagevolume=2m3,storagepressure=10bar,averagestoragetemperature=110C,anddirect
normalirradiation(DNI)=1100W/m2.
TheobtainedvaluesofthethermodynamicparametersfortheSERCandorganicRankinecycle
areshowninFigure3.Afterhavingtheresultsofalltheparametersoftheejectorrefrigerationcycle
intheEES,itisfurthermodeledinEBSILONProfessionalSoftware.Theresultsshowanexcellent
agreementwiththosedataobtainedfromtheEES.
Therefrigerationc
apacityoftheejector
refrigerationcycleis10.75kW.
(a)
(b)
Figure3.Schematicandthethermodynamicparametersfortheejectorrefrigerationcycle
(a)and
organicRankinecycle(
b
).
ForthesimulationoftheORCin EBSILONProfessional,thespecificationoftheparameterswas
takenfromthemodelreportedin[10].Thesimulationresultsofthestudiedmodelarecompared
withthoseofpublisheddata[10]giveninTable1.
Table1.Comparisonof
organicRankinecycle(
ORC)models.
Figure 3.
Schematic and the thermodynamic parameters for the ejector refrigeration cycle (
a
) and
organic Rankine cycle (b).
For the simulation of the ORC in EBSILON Professional, the specification of the parameters was
taken from the model reported in [
10
]. The simulation results of the studied model are compared with
those of published data [10] given in Table 1.
Entropy 2020,22, 702 11 of 19
Table 1. Comparison of organic Rankine cycle (ORC) models.
Variable Nomenclature Unit Model in [10] Study Model
Working fluid n-Butane n-Butane
Heat in .
Qin kW 138.17 138.13
Expander inlet .
mkg (s)−10.353 0.353
pbar 5.99 5.99
T◦C 62.0 62.0
Expander outlet .
mkg (s)−10.353 0.353
pbar 3.28 3.28
T◦C 44.19 45.00
Condenser inlet .
mkg (s)−10.353 0.353
pbar 3.28 3.28
T◦C 44.1 44.0
Condenser outlet .
mkg (s)−10.353 0.353
pbar 3.28 3.28
T◦C 35.0 35.0
Expander power .
Wex kW 8.37 8.49
Pump power .
WpkW 0.17 0.17
Net power .
Wnet kW 8.20 8.31
Energetic efficiency η% 5.93 6.14
Figure 4shows the results obtained for the SERC to evaluate the system performance.
The simulations for different generator pressures (Figure 4a,b) show the following. As the generator
pressures decrease, with the evaporator temperature and pressure, and are constant at 285.6 K and
4.5 bar, respectively, the condenser pressure decreases, and the COP increases. It was found that a
decrease of 28% in the generator pressures results in a 48% increase in the cycle COP and a decrease of
18% in the condenser pressure. Figure 4b shows the change in the COP and the entrainment ratio as
the generator temperature varies, while keeping the evaporator temperature and pressure constant at
285.6 K and 4.5 bar, respectively. As the generator temperature is decreased from 366.8 K to 350.7 K,
the COP of the cycle is increased from 0.5 to 0.75, and the entrainment ratio also increases from 0.55
to 0.85. Thus, by decreasing the generator tepmerature, the COP of the system is increased, and the
entrainment ratio is also increased.
As shown in Figure 4c, the effect of evaporator pressure on the COP and entrainment ratio is
given at a constant pressure and temperature within the generator, 33 bar and 363.9 K, respectively.
These figures depict the effect on the COP and entrainment ratio by changing evaporation pressure
from 3 bar to 4.5 bar. The values of COP and the entrainment ratio are both increased by increasing the
evaporator pressure.
Figure 4d shows the effect of evaporator pressure on the COP and the condenser pressure at
constant generator pressure and temperature. The COP of the system is increased from 0.28 to 0.53 for
the evaporator pressure change, and the condenser pressure increases as well.
Entropy 2020,22, 702 12 of 19
Entropy2020,21,x12of20
(a)
(b)
(c)
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.0
1.0
2.0
3.0
4.0
5.0
6.0
7.0
8.0
9.0
35 34 34 33 33 32 32 31 31 30 30 29 29 28 28 27 27 26 26 25
COP
CondenserPressure
GeneratorPressure,bar
COP_cooling[‐] CondenserPressure[bar]
0
0.2
0.4
0.6
0.8
1
1.2
3.0 3.1 3.2 3.2 3.3 3.4 3.5 3.6 3.6 3.7 3.8 3.9 3.9 4.0 4.1 4.2 4.3 4.3 4.4 4.5
COP_cooling\ Entrainmentratio
EvaporatorPressure[bar]
COP_cooling[‐] EntrainmentRatio
0
0.1
0.2
0.3
0.4
0.5
0.6
3.0 3.1 3.2 3.2 3.3 3.4 3.5 3.6 3.6 3.7 3.8 3.9 3.9 4.0 4.1 4.2 4.3 4.3 4.4 4.5
6
6.5
7
7.5
8
COP
Evaporatorpressure[bar]
CondenserPressure[bar]
COP_cooling[‐] CondenserPressure[Bar]
（d）
Figure 4.
Effect of generator pressure on (
a
) the coefficient of performance (COP) and condenser
pressure; (
b
) the COP and entrainment ratio; the effect of evaporator pressure on (
c
) the COP and
entrainment ratio; and (d) the COP and condenser pressure, Pg =33 bar, Tg =363.9 K, respectively.
Entropy 2020,22, 702 13 of 19
The exergy analysis was conducted in the EBSILON Professional Software, while the only
physical exergy of material streams should be considered (Figure 3a, Table 2). The values of the
exergy destruction and exergy destruction ratios are shown in Figure 5, and the exergy efficiency for
productive components is shown in Figure 6.
Table 2. Exergy rate for material streams.
State Exergy Rate [kW] State Exergy Rate [kW] State Exergy Rate [kW]
14.36 10 4.35 19 7.46
22.74 11 2.15 20 7.42
32.97 12 2.33 21 9.64
47.25 13 2.65 22 9.56
51.62 14 12.04 23 3.41
61.56 15 18.07 24 5.79
72.03 16 75.94 25 1.78
87.39 17 22.37 26 3.66
95.20 18 14.91
Entropy2020,21,x13of20
(d)
Figure4.
Effectofgeneratorpressureon(a)thecoefficientofperformance(COP)andcondenserpressure;
(b)theCOPandentrainmentratio;theeffectofevaporatorpressureon(c)theCOPandentrainmentratio;
and(d)theCOPandcondenserpressure,Pg=33bar,Tg=363.9K,respectively.
TheexergyanalysiswasconductedintheEBSILONProfessionalSoftware,whiletheonly
physicalexergyofmaterialstreamsshouldbeconsidered(Figure3a,Table2).Thevaluesofthe
exergydestructionandexergydestructionratiosareshowninFigure5,andtheexergyefficiencyfor
productivecomponentsisshowninFigure6.
Table2.Exergyrateformaterialstreams.
StateExergyRate[kW]StateExergyRate
[kW]StateExergyRate[kW]
14.36104.35197.46
22.74112.15207.42
32.97122.33219.64
47.25132.65229.56
51.621412.04233.41
61.561518.07245.79
72.031675.94251.78
87.391722.37263.66
95.201814.91
Figure5.
Exergydestruction[kW]and
exergydestructionratios[%]withinthe
groupofproductiveanddissipativecomponents.ORC,
organicRankinecycle,Ejector
CoolingCycleECC
Figure 5.
Exergy destruction [kW] and exergy destruction ratios [%] within the group of productive
and dissipative components. ORC, organic Rankine cycle, Ejector Cooling Cycle ECC.
Entropy2020,21,x14of20
Figure6.
Exergeticefficiency[%]fortheproductcomponents.
Theresultsobtainedfromtheexergeticanalysisindicatethatthecondensers(oftheERCandthe
ORC,botharedissipativecomponents)havehigherexergydestructionvalues,followedbythe
ejectorintheERC,theORCevaporator,andthesteamgenerator,asshowninFigure5.Thesolarfield
has,byfar,thehighestexergydestruction(notshowninFigure5).Theoperationconditionsofthe
condenserhavethemostsubstantialinfluenceonthedestructionofexergyandtheoverallsystem.
Thehighestexergeticefficiencyisinthecaseofgenerator,pumps,andmotors,whilethelowest
exergeticefficiencyisinthecaseoftheejectorandthesolarfield.Theexergeticefficiencyof
productivecomponents,excepttheejector,isquitehigh.Thetotalexergeticefficiencyoftheoverall
systemisaround20%.
Table3showstheassumptionsusedtoconducttheeconomicanalysis.AdetailedBMCofeach
systemcomponentiscalculatedandisshowninFigures7aand7bfortheERCandORC,respectively,
wherematerialsandpressurefactorswereconsidered.Themajorityofthecomponentswerechosen
tobemadeofcarbonsteelorstainlesssteel.ThetotalBMCofthesystemisfoundtobearound150.1
×103USD. Thelevelizedcarryingcharges(CCL)are31.7×103USD/year,andthelevelizedoperation
andmaintenancecosts(OMCL)are9.9×103USD/year.Asexpected,thehighestBMCisofthesolar
fieldorcollectorandthestoragetanks.Theresultinglevelizedcostofelectricity(LCOE)forthe
systembeingevaluatedis1.8USD/kWh.
Table3.Parametersandassumptionsforeconomicanalysis.CRF,capitalrecoveryfactor;
CELF,constantescalationlevelizationfactor.
Parameters/AssumptionsValue
Plant economic life20 years
Effective interest rate10%
CRF0.117
Average general inflation rate4.5%
Average nominal escalation rate of fuel
costs
1.7%
CELF general1.2143
CELF fuel1.3171
Annual full load operational time2000 h
Figure 6. Exergetic efficiency [%] for the product components.
The results obtained from the exergetic analysis indicate that the condensers (of the ERC and the
ORC, both are dissipative components) have higher exergy destruction values, followed by the ejector
Entropy 2020,22, 702 14 of 19
in the ERC, the ORC evaporator, and the steam generator, as shown in Figure 5. The solar field has, by
far, the highest exergy destruction (not shown in Figure 5). The operation conditions of the condenser
have the most substantial influence on the destruction of exergy and the overall system. The highest
exergetic efficiency is in the case of generator, pumps, and motors, while the lowest exergetic efficiency
is in the case of the ejector and the solar field. The exergetic efficiency of productive components,
except the ejector, is quite high. The total exergetic efficiency of the overall system is around 20%.
Table 3shows the assumptions used to conduct the economic analysis. A detailed BMC of each
system component is calculated and is shown in Figure 7a,b for the ERC and ORC, respectively,
where materials and pressure factors were considered. The majority of the components were chosen
to be made of carbon steel or stainless steel. The total BMC of the system is found to be around
150.1
×
10
3
USD. The levelized carrying charges (CCL) are 31.7
×
10
3
USD/year, and the levelized
operation and maintenance costs (OMCL) are 9.9
×
10
3
USD/year. As expected, the highest BMC is of
the solar field or collector and the storage tanks. The resulting levelized cost of electricity (LCOE) for
the system being evaluated is 1.8 USD/kWh.
Table 3.
Parameters and assumptions for economic analysis. CRF, capital recovery factor; CELF,
constant escalation levelization factor.
Parameters/Assumptions Value
Plant economic life 20 years
Effective interest rate 10%
CRF 0.117
Average general inflation rate 4.5%
Average nominal escalation rate of fuel costs 1.7%
CELF general 1.2143
CELF fuel 1.3171
Annual full load operational time 2000 h
Entropy2020,21,x15of20
(a)
(b)
(c)
Figure7.Baremodulecost(BMC)(×103USD)shareofthesystem(a)andindividualcomponents
ofERC(b)andORC(c).
Inordertoproceedwiththeexergoeconomicanalysis,thevaluesofcostrateassociatedwiththe
capitalinvestmentwithinthecomponent(𝑍) shouldbecalculatedas
Costbalances(and,ifrequired,theauxiliaryequations)wereformulatedforeachsystem
component.Costratesassociatedwithexergydestruction(ĊD,k)andexergoeconomicfactors(fk)were
calculated.
Figure8showsthesumof(Żk+ĊD,k)forthecomponentsoftheoverallsystem,andFigure9
showstheexergoeconomicfactorofthesecomponents.Highexergoeconomicfactorvaluesofa
componentsuggestadecreaseintheinvestmentcostsofthatcomponentregardlessofitsexergetic
efficiency.
𝑍𝐶𝐶𝑂𝑀𝐶∗𝐵𝑀𝐶
𝐴
𝑛𝑛𝑢𝑎𝑙 𝑡𝑖𝑚𝑒 𝑜𝑓 𝑜𝑝𝑒𝑟𝑎𝑡𝑖𝑜𝑛 ∗ 𝐶 (28)
Figure 7.
Bare module cost (BMC) (
×
10
3
USD) share of the system (
a
) and individual components of
ERC (b) and ORC (c).
Entropy 2020,22, 702 15 of 19
In order to proceed with the exergoeconomic analysis, the values of cost rate associated with the
capital investment within the component ( .
Zk) should be calculated as
.
Zk=((CCL+OMCL)∗BMCk)
Annual time of operation ∗CBMCTOT (28)
Cost balances (and, if required, the auxiliary equations) were formulated for each system
component. Cost rates associated with exergy destruction (
˙
C
D,k
) and exergoeconomic factors (f
k
)
were calculated.
Figure 8shows the sum of ( ˙
Z
k
+
˙
C
D,k
) for the components of the overall system, and Figure 9shows
the exergoeconomic factor of these components. High exergoeconomic factor values of a component
suggest a decrease in the investment costs of that component regardless of its exergetic efficiency.
Entropy2020,21,x16of20
ŻkĊD,k
Figure8.Thesumof(Żk+ĊD,k)forthecomponentsoftheoverallsystem(USD/h).
Figure9.Exergoeconomicfactor(fk)ofsystemcomponents.
Thehighestsum(Żk+ĊD,k) isforthesolarfield,followedbythecondenseroftheERCandthe
condenseroftheORC.Theexergoeconomicfactorofthesolarfieldis21%,suggestingthatthecapital
costisarelativelymuchlowerratethanthecostofexergydestruction.So,79%ofthetotalcost
associatedwiththesolarfieldisowingtoitshighthermodynamicinefficiency(highexergy
destruction).Thesecondcost‐ineffectivecomponentinthesystemisfoundtobethecondenser,and
itsexergoeconomicfactorisobservedtobe34%,whichmeansthatonly34%ofthecostisowingto
componentcapitalcostand66%ofthecostisbecauseofhighexergydestruction.Thethirdcost‐
ineffectivecomponentinthesystemisfoundtobethecondenseroftheORC,anditsexergoeconomic
factorisobtainedtobeapproximately58%,whichmeansthatonly58%ofthecostisowingto
componentcapitalcostand42%ofthecostisowingtohighexergydestruction.
5.Conclusions
Inthiswork,theERSiscombinedwiththeORC,andthemainsupplyofheatforbothcyclesis
solarenergy.ThesimulationofthecyclewascarriedoutinEBSILONProfessionalSoftware.TheERS
ismodeledinEES,andtheresultsaretakentomodeltheERSinEBSILONProfessional.
Exergyanalysisiscarriedouttofindoutthethermodynamicsinefficienciesinthesystem.The
solarfieldhasthehighestexergydestruction,whichisattributedtoheattransferacrossafinite
Figure 8. The sum of ( ˙
Zk+˙
CD,k) for the components of the overall system (USD/h).
Entropy2020,21,x16of20
ŻkĊD,k
Figure8.Thesumof(Żk+ĊD,k)forthecomponentsoftheoverallsystem(USD/h).
Figure9.Exergoeconomicfactor(fk)ofsystemcomponents.
Thehighestsum(Żk+ĊD,k) isforthesolarfield,followedbythecondenseroftheERCandthe
condenseroftheORC.Theexergoeconomicfactorofthesolarfieldis21%,suggestingthatthecapital
costisarelativelymuchlowerratethanthecostofexergydestruction.So,79%ofthetotalcost
associatedwiththesolarfieldisowingtoitshighthermodynamicinefficiency(highexergy
destruction).Thesecondcost‐ineffectivecomponentinthesystemisfoundtobethecondenser,and
itsexergoeconomicfactorisobservedtobe34%,whichmeansthatonly34%ofthecostisowingto
componentcapitalcostand66%ofthecostisbecauseofhighexergydestruction.Thethirdcost‐
ineffectivecomponentinthesystemisfoundtobethecondenseroftheORC,anditsexergoeconomic
factorisobtainedtobeapproximately58%,whichmeansthatonly58%ofthecostisowingto
componentcapitalcostand42%ofthecostisowingtohighexergydestruction.
5.Conclusions
Inthiswork,theERSiscombinedwiththeORC,andthemainsupplyofheatforbothcyclesis
solarenergy.ThesimulationofthecyclewascarriedoutinEBSILONProfessionalSoftware.TheERS
ismodeledinEES,andtheresultsaretakentomodeltheERSinEBSILONProfessional.
Exergyanalysisiscarriedouttofindoutthethermodynamicsinefficienciesinthesystem.The
solarfieldhasthehighestexergydestruction,whichisattributedtoheattransferacrossafinite
Figure 9. Exergoeconomic factor (fk) of system components.
The highest sum ( ˙
Z
k
+
˙
C
D,k
) is for the solar field, followed by the condenser of the ERC and the
condenser of the ORC. The exergoeconomic factor of the solar field is 21%, suggesting that the capital
Entropy 2020,22, 702 16 of 19
cost is a relatively much lower rate than the cost of exergy destruction. So, 79% of the total cost associated
with the solar field is owing to its high thermodynamic inefficiency (high exergy destruction). The second
cost-ineffective component in the system is found to be the condenser, and its exergoeconomic factor is
observed to be 34%, which means that only 34% of the cost is owing to component capital cost and 66%
of the cost is because of high exergy destruction. The third cost-ineffective component in the system is
found to be the condenser of the ORC, and its exergoeconomic factor is obtained to be approximately
58%, which means that only 58% of the cost is owing to component capital cost and 42% of the cost is
owing to high exergy destruction.
5. Conclusions
In this work, the ERS is combined with the ORC, and the main supply of heat for both cycles is
solar energy. The simulation of the cycle was carried out in EBSILON Professional Software. The ERS
is modeled in EES, and the results are taken to model the ERS in EBSILON Professional.
Exergy analysis is carried out to find out the thermodynamics inefficiencies in the system. The solar
field has the highest exergy destruction, which is attributed to heat transfer across a finite temperature
difference, mixing, and fluid friction. It was found that the condenser of the ERS had the highest
exergy destruction, followed by condenser of the organic Rankine cycle, ejector in the ejector ERC,
ORS evaporator, and steam generator. The total exergetic efficiency of the system obtained is 20%.
For economic analysis, the TRR method for a system was applied. The total BMC of all system
components amounted to 150.1 ×103 USD.
The exergoeconomic analysis was used to find the comparative cost importance for each component
in the system. The solar field has the highest cost associated with the component (capital cost and
the cost of exergy destruction) and the lowest exergoeconomic factor, suggesting that modern high
efficient solar technology should be used for such combined ERS/ORC systems.
Author Contributions:
Formal analysis, B.T. and T.M.; Investigation, B.T. and J.C.; Methodology, B.T. and J.C.;
Project administration, B.T. and T.M.; Software, J.C.; Supervision, B.T. and T.M. All authors have read and agreed
to the published version of the manuscript.
Funding: This research received no external funding.
Conflicts of Interest: The authors declare no conflict of interest.
Nomenclature
.
Ccost rate [USD (h)−1]
COP coefficient of performance [-]
.
Eexergy rate [W]
fexergoeconomic factor [-]
hspecific enthalpy [kJ (kg)−1]
dthroat diameter [-]
iinterest rate [%]
.
mmass flow rate [kg (s) −1]
neconomic life [year]
ppressure [bar]
.
Qheat rate [W]
rinflation rate [%]
Ttemperature [K, oC]
.
Wpower [W]
y*Dexergy destruction ratio [%]
.
Zcost rate [USD (h)−1]
Entropy 2020,22, 702 17 of 19
Greek symbols
αexponent for size component
εexergy efficiency [%]
τannual operating hours [h (year)−1]
ωentrainment ratio [-]
ηefficiency [%]
Abbreviations
AC air conditioning
BMC bare module cost
CAM constant area mixing
CC carrying charges
CELF constant escalation levelization factor
CPM constant pressure mixing
CRF capital recovery factor
DNI direct normal irradiation
ERC ejector refrigeration cycle
ERS ejector refrigeration system
FC fuel cost
FCI fixed capital investment
LCOE levelized cost of electricity
MF module factor
MPF material and pressure correction factor
OMCL levelized operation and maintenance cost
ORC organic Rankine cycle
PEC purchased equipment cost
PNL primary nozzle location
SERC solar ejector refrigeration cycle
TCI total capital investment
TRR total revenue requirement
VCRS vapor compression refrigeration system
Subs- and superscripts
0reference state (for exergy analysis)
Dexergy destruction
Fexergy of fuel
k kth component
Lexergy losses, levelized
Pproduct
tot overall system
References
1.
Bellos, E.; Tzivanidis, C. Optimum design of a solar ejector refrigeration system for various operating
scenarios. Energy Convers. Manag. 2017,154, 11–24. [CrossRef]
2.
Tashtoush, B.M.; Al-Nimr, M.A.; Khasawneh, M.A. Investigation of the use of nano-refrigerants to enhance
the performance of an ejector refrigeration system. Appl. Therm. Energy 2017,206, 1446–1463. [CrossRef]
3.
Song, J.; Zhang, X. Analysis of a Power Cycle Utilizing Low-Grade Solar Energy. In Proceedings of the
Asia-Pacific Power and Energy Engineering Conference, Chengdu, China, 28–31 March 2010. [CrossRef]
4.
Elakhdar, M.; Landoulsi, H.; Tashtoush, B.; Nehdi, E.; Kairouani, L. A combined thermal system of an
ejector refrigeration and organic rankine cycles for power generation using a solar parabolic trough.
Energy Convers. Manag. 2019,199, 111947. [CrossRef]
5.
Wang, N.; Chen, J. Theoretical analysis of organic rankine cycle combine power and ejector refrigeration
driven by solar energy. Energy Procedia 2018,152, 109–114. [CrossRef]
6.
Tashtoush, B.; Algharbawi, A. Parametric study of a novel hybrid solar variable geometry ejector cooling
with organic rankine cycles. Energy Convers. Manag. 2019,198, 111910. [CrossRef]
Entropy 2020,22, 702 18 of 19
7.
Megdouli, K.; Tashtoush, B.M.; Ejemni, N.; Nahdi, E.; Mhimid, A.; Kairouani, L. Performance analysis of a
new ejector expansion refrigeration cycle (NEERC) for power and cold: Exergy and energy points of view.
Appl. Therm. Eng. 2017,122, 39–48. [CrossRef]
8.
Megdouli, K.; Sahli, H.; Tashtoush, B.; Nahdi, E.; Kairouani, L. Theoretical research of the performance of a
novel enhanced transcritical CO
2
refrigeration cycle for power and cold generation. Energy Convers. Manag.
2019,201, 112139. [CrossRef]
9.
Dai, Y.; Wang, J.; Gao, L. Exergy analysis, parametric analysis and optimization for a novel combined power
and ejector refrigeration cycle. Appl. Therm. Eng. 2009,29, 19831–19990. [CrossRef]
10.
Li, X.; Zhao, C.; Hu, X. thermodynamic analysis of organic rankine cycle with ejector. Energy
2012
,
42, 3423–3449. [CrossRef]
11.
Gupta, D.; Kumar, R.; Kumar, N. First and second law analysis of solar operated combined Rankine and
ejector refrigeration cycle. Appl. Sol. Energy 2014,50, 113–121. [CrossRef]
12.
Habibzadeh, A.; Rashidi, M.; Galanis, N. Analysis of a combined power and ejector-refrigeration cycle using
low temperature heat. Energy Convers. Manag. 2013,65, 381–391. [CrossRef]
13.
Tashtoush, B.; Alshare, A.; Alrifai, S. Performance study of ejector cooling cycle at critical mode under
superheated primary flow. Energy Convers. Manag. 2015,94, 300–310. [CrossRef]
14.
F-Chart Software: Engineering Software. EES: Engineering Equation Solver. Available online: http:
//fchartsoftware.com/ees/(accessed on 25 September 2019).
15.
Tashtoush, B.; Nayfeh, Y. Energy and economic Analysis of a variable-geometry ejector in solar cooling
systems for residential buildings. J. Energy Storage 2020,8. [CrossRef]
16.
Elakhdar, M.; Tashtoush, B.; Nehdi, E.; Kairouani, L. Thermodynamic analysis of a novel ejector enhanced
vapor compression refrigeration (EEVCR) cycle. Energy 2018,163, 12171–12230. [CrossRef]
17.
Megdouli, K.; Tashtoush, B.; Nahdi, E.; Mhimid, A.; Kairouani, L. Thermodynamic analysis of a novel
ejector-cascade refrigeration cycles for freezing process applications and air-conditioning. Int. J. Refrig.
2016
,
70, 108–118. [CrossRef]
18.
Cihan, E.; Kavasogullari, B. Energy and exergy analysis of a combined refrigeration and waste heat driven
organic rankine cycle system. Therm. Sci. 2017,21, 2621–2631. [CrossRef]
19.
Yu, B.; Yang, J.; Wang, D.; Shi, J.; Chen, J. An updated review of recent advances on modified technologies in
transcritical CO2refrigeration cycle. Energy 2019,189, 116147. [CrossRef]
20.
Zhang, Q.; Luo, Z.; Zhao, Y.; Cao, R. Performance assessment and multi-objective optimization of a novel
transcritical CO
2
trigeneration system for a low-grade heat resource. Energy Convers. Manag.
2020
,204, 112281.
[CrossRef]
21.
Xia, W.K.; Huo, Y.W.; Song, Y.F.; Han, J.M.; Dai, Y.P. Off-design Analysis of a CO
2
Rankine cycle for the
recovery of LNG cold energy with ambient air as heat source. Energy Convers. Manag.
2019
,165, 116–125.
[CrossRef]
22.
Darvish, K.; Ehyaei, M.; Atabi, F.; Rosen, M. Selection of optimum working fluid for organic rankine.
Sustainability 2015,7, 15362–15383. [CrossRef]
23.
STEAG Energy Services GmbH, “Products: EBSILON
®
Professional,” STEAG Energy Services–System
Technologies, [Online]. Available online: https://www.steagsystemtechnologies.com/en/products/ebsilon-
professional/(accessed on 18 April 2018).
24.
Tashtoush, B.; Bani Younes, M. Comparative thermodynamic study of refrigerants to select the best
environment-friendly refrigerant for use in a solar ejector cooling system. Arab. J. Sci. Eng.
2019
,
44, 1165–1184. [CrossRef]
25. Bejan, A.; Tsatsaronis, G.; Moran, M. Thermal Design and Optimization; Wiley: Hoboken, NJ, USA, 1995.
26.
Ko, H.; Kim, K. Exergy Analysis of organic rankine cycle with ejector using dry fluids. Int. J. Min. Met.
Mech. Eng. 2015,3, 213–218.
27.
Megdouli, K.; Tashtoush, B.; Nahdi, E.; Kairouani, L.; Mhimid, A. Performance analysis of a combined vapor
compression cycle and ejector cycle for refrigeration cogeneration. Int. J. Refrig.
2017
,74, 515–525. [CrossRef]
28.
Sun, W.; Yue, X.; Wang, Y. Exergy efficiency analysis of ORC (Organic Rankine Cycle) and ORC-based
combined cycles driven by low-temperature waste heat. Energy Convers. Manag.
2017
,135, 63–73. [CrossRef]
29.
Rostamzadeh, H.; Ebadollahi, M.; Ghaebi, H.; Amidpour, M.; Kheiri, R. Energy and exergy analysis of novel
combined cooling and power (CCP) cycles. Appl. Thermal Eng. 2017,124, 152–169. [CrossRef]
Entropy 2020,22, 702 19 of 19
30.
Javanshir, N.; Mahmoudi, S.; Rosen, M. Thermodynamic and exergoeconomic analyses of a novel combined
cycle comprised of vapor-compression refrigeration and organic rankine cycles. Sustainability
2019
,11, 3374.
[CrossRef]
31.
Zhang, K.; Chen, X.; Markides, C.; Yang, Y.; Shen, S. Evaluation of ejector performance for an organic Rankine
cycle combined power and cooling system. Appl. Energy 2016,184, 404–412. [CrossRef]
32.
Chen, J.; Havtun, H.; Palm, B. Conventional and advanced exergy analysis of an ejector refrigeration.
Appl. Energy 2015,144, 139–151. [CrossRef]
33.
Saleh, B. Performance analysis and working fluid selection for ejector refrigeration cycle. Appl. Therm. Eng.
2016,107, 114–124. [CrossRef]
34.
Jenkins, S. CEPCI Updates: January 2018 (prelim.) and December 2017 (final) - Chemical Engineering
Essentials for Professionals. Available online: https://www.chemengonline.com/2017-cepci-updates-dec-
prelim-and-nov-final/(accessed on 25 August 2019).
35.
Wu, D.; Han, Z.H.; Liu, Z.J.; Zhan, H. Study on configuration optimization and economic feasibility analysis
for combined cooling, heating and power system. Energy Convers Manag. 2019,190, 91–104. [CrossRef]
36.
Meng, F.X.; Wang, E.H.; Zhang, F.; Zhao, C. Thermo-economic Analysis of transcritical CO
2
power cycle and
comparison with Kalina cycle and ORC for a low temperature heat source. Energy Convers Manag.
2019
,
195, 1295–1308. [CrossRef]
37.
Liu, Z.; Cao, F.; Guo, J.Z.; Liu, J.; Zhai, H.; Duan, Z. Performance analysis of a novel combined cooling, heating
and power system based on carbon dioxide energy storage. Energy Convers. Manag.
2019
,188, 151–161.
[CrossRef]
38.
Takleh, H.; Zare, V. Performance improvement of ejector expansion refrigeration cycles employing a booster
compressor using different refrigerants: Thermodynamic Analysis and optimization. Int. J. Refrig.
2019
,
101, 56–70.
©
2020 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access
article distributed under the terms and conditions of the Creative Commons Attribution
(CC BY) license (http://creativecommons.org/licenses/by/4.0/).
