PERFORMANCE ANALYSIS OF AN ABSORPTION & EJECTOR REFRIGERATION SYSTEM FOR COOLING APPLICATIONS

Abhishek Verma

S.C. Kaushik

S.K. Tyagi

Department of Energy Science and Engineering, Indian Institute of Technology Delhi, New Delhi, India


In this article, a theoretical evaluation of a combined absorption and ejector refrigeration cycle (ERC) is presented that produces additional cooling at a moderate temperature of 7°C while producing low-temperature refrigeration at –25°C. For this system, solar-derived electricity can be used as the energy input (for the compressor) and the dual cooling outputs can be utilized for underground vegetable applications and other cooling applications. The proposed system couples a CO2-based ERC and a single-effect LiBr-H2O absorption chiller. The two systems are linked by the waste heat ejected from the gas cooler of the ejector cycle, which powers the absorption chiller. For a particular set of operating conditions, energy and exergy evaluations have been performed for the complete system to estimate the optimum performance of the combined system. Additionally, the combined system's performance metrics were compared to those of a stand-alone, conventional CO2 ejector refrigeration system (ERS). It was found that the coefficient of performance (COP) and exergy efficiency (across the basic ejector cycle) were improved by 16.4 and 4.1%, respectively, indicating a substantial boost in the performance of the combined cycle.

KEY WORDS: absorption refrigeration, CO2-based ejector refrigeration, waste heat recovery, exergy analysis

1. INTRODUCTION

An ejector cooling cycle is a type of refrigeration cycle that uses a high-pressure fluid to entrain and compress a low-pressure fluid. The cycle begins with a high-pressure fluid (usually steam) entering the ejector at high velocity through a converging nozzle. This creates a low-pressure region at the throat of the nozzle, which draws in a low-pressure fluid (usually refrigerant) from the evaporator. The high-velocity steam and low-pressure refrigerant mix and flow through a diffuser, which slows down the mixture and increases its pressure. The mixture then enters a condenser, where it gives up heat to the surroundings and condenses into a high-pressure liquid. The high-pressure liquid then flows through an expansion valve, which reduces its pressure and temperature, causing it to evaporate. The low-pressure refrigerant then flows back to the ejector, where the cycle repeats. Overall, the ejector cooling cycle is a simple and efficient way to create a cooling effect without the need for moving mechanical parts, such as compressors. However, it requires a high-pressure fluid (usually steam), which can limit its practical applications.

The CO2-based ejector refrigeration cycle (ERC) is an economically viable and environmentally benign option to achieve low-temperature refrigeration, but it has a low coefficient of performance (COP) because the pressure ratio is higher for lower evaporator temperatures (Yari and Mahmoudi, 2011). Due to the higher pressure ratio, the pressure and temperature at the exit of the compressor are quite high and a lot of low-grade energy at higher temperatures is wasted in the atmosphere. Many researchers have introduced ejector expansion to lower the throttling losses and to enhance the COP of the refrigeration system (Expósito Carrillo et al., 2017; Ghaebi et al., 2017; Ünal et al., 2017).

A trans-critical CO2 ejector refrigeration system (ERS) was theoretically analyzed by Deng et al. (2007). They examined the relationship between the entrainment ratio of the ejector and the vapr quality at the exit of the ejector. It was reported that a large percentage of waste heat at high temperatures is being discharged into the atmosphere by industries. However, this heat can potentially be beneficially utilized to produce refrigeration and space conditioning at different temperatures through the integration of different cooling technologies (Khaliq, 2015; Kumar et al., 2020). An absorption cooling cycle is another type of refrigeration cycle, but it uses a chemical process to absorb and release the refrigerant. The cycle begins with a mixture of refrigerant and absorbent (e.g., H2O-lithium bromide) in the absorber. The mixture is heated by a heat source (such as waste heat or solar energy) to boil off the refrigerant, leaving behind a concentrated absorbent. The refrigerant vapor then flows to the condenser, where it gives up heat to the surroundings and condenses into a high-pressure liquid. The high-pressure liquid refrigerant then flows through an expansion valve, which reduces its pressure and temperature, causing it to evaporate. The low-pressure refrigerant vapor then flows to the evaporator, where it absorbs heat from the surroundings and vaporizes again. The low-pressure refrigerant vapor then flows back to the absorber, where it is absorbed by the concentrated absorbent, starting the cycle over again. Thus, the absorption cooling cycle provides a thermal pathway to cooling by avoiding the need for mechanical compression. It is well known that the absorption refrigeration technique can easily be operated by low-grade thermal energy, and the required generator temperature to produce cooling varies from 60 to 200°C, depending on the single/double effect configuration of the absorption refrigeration system (Verma et al., 2016, 2021b; Bhatti et al., 2021; Chauhan et al., 2019).

There is a lack of comprehensive studies on the performance of the combined absorption and trans-critical CO2 based ERS. Although previous studies may have focused on the individual type of refrigeration cycles, without a detailed analysis of the combined system. The performance analysis of this specific combined refrigeration system provides valuable insights into the potential benefits, limitations, and optimum parameters to enhance energy efficiency. Also, its findings could help to inform future researchers and guide engineers in the development of more efficient and sustainable refrigeration systems.

The present work deals with the integration of the CO2-based ERC and absorption chiller (single effect) with H2O-LiBr as the working pair—where the absorption chiller is operated on the waste heat rejected in the gas cooler of the ejector cycle. The combined system produces low-temperature refrigeration for freezing applications (at –25°C) and an additional cooling effect for cold storage (at 7°C), which can be utilized for underground vegetable storage applications and other cooling applications. The complete system has been analyzed on the basis of its overall energy and exergy performance. The analysis includes a parametric study to find the optimum conditions to achieve maximum exergetic efficiency. Furthermore, the performance parameters for the integrated cycle have been compared to those of the basic ERS utilizing CO2 as a refrigerant for a typical set of operating conditions.

2. COMBINED CYCLE DESCRIPTION

A novel configuration of the refrigeration system is studied that aims to produce both low-temperature refrigeration and moderate space cooling while utilizing the waste heat of the system as shown in Fig. 1. The proposed system includes a CO2-based ERS and a single effect absorption chiller (SEACH), where LiBr-H2O was employed as the working fluid pair. The compressor, gas coolers, ejector, separator, and evaporator are the essential components of an ERS, as shown in Fig. 1.

Combined absorption and CO2-based ejector refrigeration system (Reprinted from Verma et al. with permission from Interscience Publishers, Copyright 2022)

Figure 1. Combined absorption and CO2-based ejector refrigeration system (Reprinted from Verma et al. with permission from Interscience Publishers, Copyright 2022)

In the combined system, the ejector cycle produces low-temperature refrigeration of –25°C, while the absorption chiller produces cooling at a moderate temperature of 7°C. In the present work, the waste heat energy was delivered to the generator of the SEACH from the gas cooler of the ERS via a water-steam loop (Verma et al., 2022). The cycle starts with steam at 100°C entering the generator of the SEACH via a water–steam loop, which maintains the generator at a constant temperature of 90°C (Verma et al., 2021a). The heat energy delivered to the generator is utilized to generate the refrigerant (water) vapor, which gets condensed into the condenser while rejecting heat into the sink. Next, the refrigerant water was expanded via an expansion valve to produce additional cooling at 7°C.

3. THERMODYNAMIC MODELING

The analysis includes the fundamental mass balance, material (species) balance, energy conservation, and exergy balance for each section as a separate control volume with no accumulation of mass and energy:

\(\sum\dot{m}_i-\sum\dot{m}_e=0\) (1)

\(\sum\dot{m}_i\dot{x}_i-\sum\dot{m}_e\dot{x}_e=0\) (2)

\(\sum\dot{Q}-\sum\dot{W}=\sum\dot{m}_e\dot{h}_e-\sum\dot{m}_i\dot{h}_i\) (3)

The cooling performance indicator based on energy analysis is defined by the COP for each cycle. The COP for the ejector cycle is given as follows:

\(\text{COP}_{\text{TCEJRS}}=\dfrac{\dot{Q}_{\text{Etc.}}}{\dot{W}_{\text{Comp}}}\) (4)

The COP for the SEACH is given as follows:

\(\text{COP}_{\text{SEACH}}=\dfrac{\dot{Q}_{\text{Eva.}}}{\dot{Q}_G+{\dot{W}}_p}\) (5)

The COP of the combined system is given as follows:

\(\text{COP}_{\text{NET}}=\dfrac{\dot{Q}_{\text{Etc.}}+\dot{Q}_{\text{Eva.}}}{\dot{W}_{\text{Comp}}+\dot{W}_p}\) (6)

Exergy is stated as the highest amount of reversible work that may be obtained while bringing the system's state to equilibrium with ambient conditions. The physical exergy component for a stream for each state point is defined by the rate of exergy flow (Dincer and Rosen, 2013), as follows:

\(\dot{E}=\dot{m}\left[(h-h_0)-T_0(s-s_0)\right]\) (7)

The exergy destruction rate (ED) for each component in a steady-state process can be determined as follows:

\(\dot{\text{ED}}=\sum\dot{E}_i-\sum\dot{E}_e+\sum\dot{Q}\left(1-\dfrac{T_0}{T}\right)-\sum\dot{W}\) (8)

The cooling performance indicator based on exergy analysis is defined by the exergy efficiency for individual cycles can be found from the following:

\(\eta_{ex_{\text{EJT}}}=\dfrac{\dot{Q}_{\text{ECT}}\left|1-\frac{T_0}{T_R}\right|}{\dot{W}_{\text{Comp}}}\) (9)

\(\eta_{ex_{\text{SEACH}}}=\dfrac{\dot{Q}_E\left|1-\frac{T_0}{T_r}\right|}{(\dot{E}_{30}-\dot{E}_{31})+\dot{W}_p}\) (10)

\(\eta_{ex_{\text{Net}}}=\dfrac{\dot{Q}_{\text{ETC}}\left|1-\frac{T_0}{T_R}\right|+\dot{Q}_E\left|1-\frac{T_0}{T_r}\right|}{\dot{W}_{\text{Comp}}+\dot{W}_p}\) (11)

3.1 Component-Level Analysis

The thermodynamic equations including energy balance and exergy destruction rate applied to each system component are shown in Table 1. Based on the schematic representation of Fig. 1, the state point numbers of the system are used in the combined configuration, which led to the expressions that follow.

TABLE 1: Thermodynamic relations utilized in the study for analysis, based on Verma et al. (2022)

Elements Energy Balances Exergy Balances
Compressor \(\eta_{\text{Comp}}=\dfrac{h_{2s}-h_1}{h_2-h_1}\), \(\dot{W}_{\text{Comp}}=\dfrac{h_2-h_1}{1+\mu}\)
\(\eta_{\text{Comp}}=1.003-0.121\left(\dfrac{P_{\text{dis}}}{P_{\text{suc}}}\right)\)
\(\dot{\text{ED}}_{\text{Comp}}=\dot{E}_1+\dot{W}_{\text{Comp}}-\dot{E}_2\)
Gas cooler 1 (GC1) \(\varepsilon_{{\text{GC}}_{1}}=\dfrac{T_2-T_3}{T_2-T_{31}}\), \({\dot{Q}}_{{\text{GC}}_1}=\dfrac{h_2-h_3}{1+\mu}\) \(\dot{\text{ED}}_{{\text{EG}}_1}=\dot{E}_2+\dot{E}_{30}-\dot{E}_3-\dot{E}_{31}\)
Gas cooler 2 (GC2) \({\varepsilon }_{{\text{GC}}_2}=\dfrac{T_{27}-T_{26}}{T_3-T_{26}}\), \(\dot{Q}_{{\text{GC}}_2}=\dfrac{h_3-h_4}{1+\mu}\) \(\dot{\text{ED}}_{{\text{GC}}_2}=\dot{E}_3+\dot{E}_{26}-\dot{E}_4-\dot{E}_{27}\)
Ejector \(\eta_N=\dfrac{h_4-h_5}{h_4-h_{5s}}\), \(h_4=h_5+\dfrac{u_5^2}{2}\), \(x_7=\dfrac{1}{1+\mu}\)
\(u_6=\left(\dfrac{1}{1+\mu}\right)u_5\), \(h_7=\left(\dfrac{1}{1+\mu}\right)h_4+\left(\dfrac{\mu}{1+\mu}\right)h_{10}\)
\(\eta_D=\dfrac{h_{7s}-h_6}{h_7-h_6}\), \(h_7=h_6+\dfrac{u_6^2}{2}\)
\({\dot{\text{ED}}}_{\text{EJT}}={\dot{E}}_4+{\dot{E}}_{10}-{\dot{E}}_7\)
Separator \(\dot{m}_7h_7=\dot{m}_1h_1+\dot{m}_8h_8\) \(\dot{\text{ED}}_{\text{sep}}=\dot{E}_7-\dot{E}_1-\dot{E}_8\)
Expansion valve 1 \(h_9=h_8\) \(\dot{\text{ED}}_{\text{exp}1}=\dot{E}_8-\dot{E}_9\)
Evaporator (ERS) \(\dot{Q}_{\text{ETC}}=\left(\dfrac{\mu}{1+\mu}\right)(h_{10}-h_9)\) \(\dot{\text{ED}}_{\text{ETC}}=\dot{E}_9+\dot{Q}_{\text{ETC}}\left(1-\dfrac{T_0}{T_R}\right)-\dot{E}_{10}\)
Generator \(\dot{Q}_G+\dot{m}_{14}h_{14}=\dot{m}_{15}h_{15}+\dot{m}_{18}\), \(h_{18}\dot{Q}_G=\dot{Q}_{{\text{GC}}_1}\) \(\dot{\text{ED}}_G=\dot{E}_{14}+\dot{E}_{31}-\dot{E}_{30}-\dot{E}_{15}-\dot{E}_{18}\)
Solution HX \(\varepsilon_{\text{SHX}}=\dfrac{h_{15}-h_{16}}{h_{15}-h_{13}}\), \(\dot{Q}_{\text{SHX}}+\dot{m}_{13}h_{13}=\dot{m}_{14}h_{14}\) \(\dot{\text{ED}}_{\text{SHX}}=\dot{E}_{13}+\dot{E}_{15}-\dot{E}_{16}-\dot{E}_{14}\)
Absorber \(\dot{Q}_A+\dot{m}_{12}h_{12}=\dot{m}_{21}h_{21}+\dot{m}_{17}h_{17}\) \(\dot{\text{ED}}_A=\dot{E}_{21}+\dot{E}_{19}+\dot{E}_{24}-\dot{E}_{12}-\dot{E}_{25}\)
Pump \(\dot{W}_p=\dot{m}_{12}v_{12}(P_{13}-P_{12})\) \(\dot{\text{ED}}_P=\dot{E}_{12}+\dot{E}_{13}-\dot{W}_p\)
Solution throttle valve \(h_{16}=h_{17}\) \(\dot{\text{ED}}_{\text{STV}}=\dot{E}_{16}-\dot{E}_{17}\)
Expansion valve 2 \(h_{19}=h_{20}\) \(\dot{\text{ED}}_{\text{exp}2}=\dot{E}_{19}-\dot{E}_{20}\)
Evaporator (SEACH) \(\dot{Q}_E+\dot{m}_{20}h_{20}=\dot{m}_{21}h_{21}\) \(\dot{\text{ED}}_E=\dot{E}_{20}+\dot{Q}_E\left(1-\dfrac{T_0}{T_r}\right)-\dot{E}_{21}\)
Condenser \(\dot{Q}_C+\dot{m}_{19}h_{19}=\dot{m}_{18}h_{18}\) \(\dot{\text{ED}}_{C}=\dot{E}_{18}+\dot{E}_{22}-\dot{E}_{19}-\dot{E}_{23}\)

3.1.1 Input Parameters

The constant input parameters assumed for the parametric analysis of the combined system are as follows:

Evaporator temperature (\(T_{\text{ETC}}\)) is –25°C.

Gas cooler exit temperature (\(T_{\text{GC}}\)) is 36°C.

Generator temperature (\(T_{G}\)) = 90°C.

Evaporator temperature (\(T_{E}\)) is 7°C.

Condenser/absorber temperature (\(T_{C}/T_{A}\)) is 35°C.

Mass flow rate of CO2 (\(m_{r\text{EJT}}\)) is 1 kg/s.

Nozzle efficiency (\(\eta_{N}\)) is 0.7.

Diffuser efficiency (\(\eta_{D}\)) is 0.8.

Gas coolers effectiveness (\(\varepsilon_{\text{GC}1,2}\)) is 0.8.

Solution heat exchanger effectiveness (\(\varepsilon_{\text{SHX}}\)) is 0.7.

4. RESULTS AND DISCUSSION

The energy and exergy analysis of the CO2-based ERS integrated with a SEACH was carried out using a computer model in Engineering Equation Solver, following the basic mathematical formulations listed in Table 1. The properties of the working fluid pairing of LiBr-H2O were taken from Pátek and Klomfar (2006). For the evaluation of performance parameters, the evaporation temperature of –25°C in the ERS and evaporation temperature of 7°C in the SEACH and the gas cooler exit temperature of 36°C, with the optimal pressure of the gas cooler as 8,610 kPa are the independent parameters. The implications of combined absorption and CO2-based ERSs would be of interest to engineers and designers of cooling systems, as well as to policymakers concerned with energy efficiency and sustainability. The findings of the research could be used to inform the development of more efficient and environmentally friendly cooling systems, which could have a significant impact on reducing energy consumption and greenhouse gas emissions.

4.1 Exergy Destruction in Various Components of the Combined Cycle

The exergy destruction in various components of the ERS and SEACH are shown in Figs. 2 and 3, respectively. In the ERS, the total exergy destruction was found to be 53.27 kW, while in the SEACH it is found to be 2.73 kW, which is just 5.12% of the former. Alternatively, maximum exergy destruction of 28.24 kW was found to be in the compressor of the former cycle, which is ∼53% of the total destruction in ERS. Thus, the compressor typically represents the highest portion of exergy destruction for the combined cycle, while the absorber represents the highest exergy destruction for the absorption cycle as it accounts for ∼37% of the total destruction in the SEACH.

Exergy destruction in different components of the ERS

Figure 2. Exergy destruction in different components of the ERS

Exergy destruction in different components of the SEACH

Figure 3. Exergy destruction in different components of the SEACH

In the ERS, the next highest energy destruction components are the gas cooler (GC2) and evaporator. The exergy destruction in the gas cooler (GC1) is less as the heat is rejected, but in the combined cycle this is utilized to operate the SEACH. The exergy destruction in these components is due to the higher pressure ratio and the high heat rejection pressure and temperature of CO2. In the SEACH, the highest exergy destruction was found in the absorber, followed by the generator, condenser, and evaporator. In the absorber, the formation of heat due to the mixing of refrigerant vapor with the H2O-LiBr solution leads to higher entropy generation, resulting in more exergy destruction in the component.

4.2 COP and Exergetic Efficiency versus Entrainment Ratio

The ejector cycle COP and exergetic efficiency varied with the entrainment ratio at a few evaporating temperatures, as seen in Figs. 4(a) and 4(b), respectively. As the entrainment ratio increases, the amount of refrigerant vapor in the compressor and the amount of refrigerant liquid in the evaporator increases; hence, the COP of the ejector cycle first increases with the rise in entrainment ratio, reaches a peak corresponding to the optimum entrainment ratio, and then declines with a further rise of the entrainment ratio. A similar trend is seen for exergetic efficiency as a function of the entrainment ratio.

  
(a) (b)

Figure 4. COP and exergy efficiency with entrainment ratio for different evaporator temperatures of the ejector refrigeration cycle. (a) COP vs. entrainment ratio, (b) exergy efficiency vs. entrainment ratio.

The maximum cooling COP is obtained by varying the entrainment ratio from 0.4 to 0.5 for the given set of operating conditions. With the rise in entrainment ratio, the refrigerant quality at the ejector outlet diminishes and the compressor work increases, resulting in a reduction in COP values. A similar phenomenon has been observed by Deng et al. (2007) and Disawas and Wongwises (2004), wherein the entrainment ratio is dependent on the \(P_{\text{GC}}\), which is indirectly responsible for producing refrigerant vapor and refrigerant liquid in the compressor and evaporator, respectively. Thus, there is an optimal value of \(P_{\text{GC}}\) that maximizes the COP and exergetic efficiency for a given set of operational conditions. For example, in an ERS with an evaporation temperature of –25°C and a heat rejection temperature in the gas cooler of 36°C, the optimum \(P_{\text{GC}}\) (8,610 kPa) yields the maximum COP (of ∼1.09), while the corresponding exergetic efficiency was found to be 19.47%.

Furthermore, the performance of the combined refrigeration cycle was compared to the conventional ERC with similar input parameters. It is found that at an optimum (i.e., for a gas cooler pressure of 8,610 kPa and an entrainment ratio of 0.444), the overall COP of the combined cycle is increased by 16.36% and the corresponding exergy efficiency has improved by 4.1%, compared to the base TCEJRC as depicted in Table 2. The improvement in COP and exergy efficiency is due to the utilization of waste heat of the tc-CO2 ERC to run the absorption chiller to get an additional cooling capacity at a temperature of 7°C in the evaporator of the absorption chiller without the use of any external source of heat.

TABLE 2: Comparison of performance (COP and \(\eta_{ex}\)) to the base ERS cycle

Parameter ERS SEACH Combined System Increase (%)
COP 1.09 0.77 1.3 16.4
\(\boldsymbol{\eta_{ex}}\) (%) 19.5 17.6 20.3 4.1

5. CONCLUSIONS

A parametric energetic and exergetic analysis of a combined ERS and SEACH system has been carried out to determine its potential to enhance performance over a stand-alone cycle. On the basis of the investigation of the integrated cycle, the following conclusions were drawn:

  • For a specific set of operating constraints, there exists an optimum value of the entrainment ratio of the ejector for steady-state operation. The COP and exergetic efficiency of the cycle increases with the entrainment ratio (μ), achieves a peak value, and then declines gradually. As a result, there is an optimum value of the entrainment ratio (μ) for which the cycle performs at its best. In the current study, the optimal value of μ is 0.444, which corresponds to an optimal gas cooler pressure of 8,610 kPa.

  • There is an enhancement in both COP and exergy efficiency over the basic ERS. The combined cycle COP was enhanced by 16.4%, while its exergetic efficiency was improved by 4.1%.

  • The combined cycle COP and energy efficiency rise with evaporator temperature, but the tendency reverses when there is a rise in gas cooler exit temperature.

  • The compressor shows the highest exergy destruction in the combined system (∼53% of the total exergy destruction in the ERS), followed by the ejector and the gas cooler. In the SEACH part of the cycle, the highest exergy destruction was found in the absorber, which represents ∼37% of the total exergy destruction.

REFERENCES

Bhatti, S.S., Tyagi, S.K., and Verma, A. (2021) Energy and Exergy Analysis of Vapour Absorption Cooling System Driven by Exhaust Heat of IC Engine, Advances in Air Conditioning and Refrigeration: Select Proceedings of RAAR 2019, Singapore: Springer, 269–276.

Chauhan, P., Verma, A., Bhatti, S., and Tyagi, S. (2019) An Overview on Mathematical Models of Adsorption Refrigeration System, J. Mater. Sci. Mech. Eng., 6: 275–278.

Deng, J.Q., Jiang, P., Lu, T., and Lu, W. (2007) Particular Characteristics of Transcritical CO2 Refrigeration Cycle with an Ejector, Appl. Therm. Eng., 27: 381–388.

Dincer, I. and Rosen, M.A. (2013) Exergy, Exergy, Amsterdam: Elsevier.

Disawas, S. and Wongwises, S. (2004) Experimental Investigation on the Performance of the Refrigeration Cycle Using a Two-Phase Ejector as an Expansion Device, Int. J. Refrig., 27: 587–594.

Expósito Carrillo, J.A., Sánchez de La Flor, F.J., and Salmerón Lissén, J.M. (2017) Thermodynamic Comparison of Ejector Cooling Cycles. Ejector Characterisation by Means of Entrainment Ratio and Compression Efficiency, Int. J. Refrig., 74: 371–384.

Ghaebi, H., Parikhani, T., Rostamzadeh, H., and Farhang, B. (2017) Thermodynamic and Thermoeconomic Analysis and Optimization of a Novel Combined Cooling and Power (CCP) Cycle by Integrating of Ejector Refrigeration and Kalina Cycles, Energy, 139: 262–276.

Khaliq, A. (2015) Performance Analysis of a Waste-Heat-Powered Thermodynamic Cycle for Multieffect Refrigeration, Int. J. Energy Res., 39: 529–542.

Kumar, K., Gupta, H.K., and Kumar, P. (2020) Analysis of a Hybrid Transcritical CO2 Vapor Compression and Vapor Ejector Refrigeration System, Appl. Therm. Eng., 181: 115945.

Pátek, J. and Klomfar, J. (2006) A Computationally Effective Formulation of the Thermodynamic Properties of LiBr–H2O Solutions from 273 to 500 K over Full Composition Range, Int. J. Refrig., 29: 566–578.

Ünal, Ş., Erdinç, M.T., and Kutlu, Ç. (2017) Optimal Thermodynamic Parameters of Two-Phase Ejector Refrigeration System for Buses, Appl. Therm. Eng., 124: 1354–1367.

Verma, A., Arora, A., and Mishra, R.S. (2016). Energy Analysis and Optimization of Flat Pate Collector Area of a Solar Driven Water-Lithium Bromide Half Effect Vapour Absorption Refrigeration System for a Given Cooling Load, Proc. of Int. Conf. on Recent Advances in Mechanical Engineering, Dwarka, New Delhi: Enriched Publications Pvt. Ltd, 521–528.

Verma, A., Kaushik, S.C., and Tyagi, S.K. (2022) Energy and Exergy Analysis of a Novel Ejector-Absorption Combined Refrigeration Cycle Using Natural Refrigerants, Int. J. Exergy, 39: 142.

Verma, A., Kaushik, S.C., and Tyagi, S.K. (2021a) Thermodynamic Analysis of a Combined Single Effect Vapour Absorption System and tc-CO2 Compression Refrigeration System, HighTech Innov. J., 2(2): 87–98.

Verma, A., Tyagi, S.K., and Kaushik, S.C. (2021b) Exergy Analysis and Cost Optimization of Solar Flat Pate Collector for a Two-Stage Absorption Refrigeration System with Water-Lithium Bromide as a Working Pair, Proc. of 7th Int. Conf. on Advances in Energy Research, Singapore: Springer, 599–610.

Yari, M. and Mahmoudi, S.M.S. (2011) Thermodynamic Analysis and Optimization of Novel Ejector-Expansion TRCC (Transcritical CO2) Cascade Refrigeration Cycles (Novel Transcritical CO2 Cycle), Energy, 36: 6839–6850.

References

  1. Bhatti, S.S., Tyagi, S.K., and Verma, A. (2021) Energy and Exergy Analysis of Vapour Absorption Cooling System Driven by Exhaust Heat of IC Engine, Advances in Air Conditioning and Refrigeration: Select Proceedings of RAAR 2019, Singapore: Springer, 269–276.
  2. Chauhan, P., Verma, A., Bhatti, S., and Tyagi, S. (2019) An Overview on Mathematical Models of Adsorption Refrigeration System, J. Mater. Sci. Mech. Eng., 6: 275–278.
  3. Deng, J.Q., Jiang, P., Lu, T., and Lu, W. (2007) Particular Characteristics of Transcritical CO2 Refrigeration Cycle with an Ejector, Appl. Therm. Eng., 27: 381–388.
  4. Dincer, I. and Rosen, M.A. (2013) Exergy, Exergy, Amsterdam: Elsevier.
  5. Disawas, S. and Wongwises, S. (2004) Experimental Investigation on the Performance of the Refrigeration Cycle Using a Two-Phase Ejector as an Expansion Device, Int. J. Refrig., 27: 587–594.
  6. Expósito Carrillo, J.A., Sánchez de La Flor, F.J., and Salmerón Lissén, J.M. (2017) Thermodynamic Comparison of Ejector Cooling Cycles. Ejector Characterisation by Means of Entrainment Ratio and Compression Efficiency, Int. J. Refrig., 74: 371–384.
  7. Ghaebi, H., Parikhani, T., Rostamzadeh, H., and Farhang, B. (2017) Thermodynamic and Thermoeconomic Analysis and Optimization of a Novel Combined Cooling and Power (CCP) Cycle by Integrating of Ejector Refrigeration and Kalina Cycles, Energy, 139: 262–276.
  8. Khaliq, A. (2015) Performance Analysis of a Waste-Heat-Powered Thermodynamic Cycle for Multieffect Refrigeration, Int. J. Energy Res., 39: 529–542.
  9. Kumar, K., Gupta, H.K., and Kumar, P. (2020) Analysis of a Hybrid Transcritical CO2 Vapor Compression and Vapor Ejector Refrigeration System, Appl. Therm. Eng., 181: 115945.
  10. Pátek, J. and Klomfar, J. (2006) A Computationally Effective Formulation of the Thermodynamic Properties of LiBr–H2O Solutions from 273 to 500 K over Full Composition Range, Int. J. Refrig., 29: 566–578.
  11. Ünal, Ş., Erdinç, M.T., and Kutlu, Ç. (2017) Optimal Thermodynamic Parameters of Two-Phase Ejector Refrigeration System for Buses, Appl. Therm. Eng., 124: 1354–1367.
  12. Verma, A., Arora, A., and Mishra, R.S. (2016). Energy Analysis and Optimization of Flat Pate Collector Area of a Solar Driven Water-Lithium Bromide Half Effect Vapour Absorption Refrigeration System for a Given Cooling Load, Proc. of Int. Conf. on Recent Advances in Mechanical Engineering, Dwarka, New Delhi: Enriched Publications Pvt. Ltd, 521–528.
  13. Verma, A., Kaushik, S.C., and Tyagi, S.K. (2022) Energy and Exergy Analysis of a Novel Ejector-Absorption Combined Refrigeration Cycle Using Natural Refrigerants, Int. J. Exergy, 39: 142.
  14. Verma, A., Kaushik, S.C., and Tyagi, S.K. (2021a) Thermodynamic Analysis of a Combined Single Effect Vapour Absorption System and tc-CO2 Compression Refrigeration System, HighTech Innov. J., 2(2): 87–98.
  15. Verma, A., Tyagi, S.K., and Kaushik, S.C. (2021b) Exergy Analysis and Cost Optimization of Solar Flat Pate Collector for a Two-Stage Absorption Refrigeration System with Water-Lithium Bromide as a Working Pair, Proc. of 7th Int. Conf. on Advances in Energy Research, Singapore: Springer, 599–610.
  16. Yari, M. and Mahmoudi, S.M.S. (2011) Thermodynamic Analysis and Optimization of Novel Ejector-Expansion TRCC (Transcritical CO2) Cascade Refrigeration Cycles (Novel Transcritical CO2 Cycle), Energy, 36: 6839–6850.
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