Coefficient Of Performance Research Articles

Modelling and Simulation of Chemical Adsorption Heat Pump for Drying and Heating Applications

The performance of a chemical adsorption heat pump drying system is largely influenced by the selection of working fluid, operating conditions, and system configuration and design. In this study, tomato slices were dried at five different air temperatures (35 °C, 40 °C, 45 °C, 50 °C, and 55 °C) with a tomato slice flow rate of 400 kg/hr and an air flow rate of 200 kg/hr using a modelled and simulated chemical adsorption heat pump drying system. Four adsorbent-adsorbate pairs were used: magnesium chloride-methanol, calcium chloride-ethanol, calcium chloride-water, and aluminium trifluoride-dimethyl ether, at evaporating and condensing temperatures of 10 °C and 15 °C, respectively. The specific moisture extraction rate ranged from 0.116 kg/kWh to 0.149 kg/kWh. The coefficient of performance (COP) of the heat pump drying (HPD) system ranged from 0.960 to 0.987, and the overall exergy efficiency at the highest ambient air temperature (30 °C) ranged from 3.84% to 20.29%. Exergy analysis of the system's components revealed that the condenser and evaporator contributed significantly to exergy destruction, exhibiting low exergy efficiency.

COMPARATIVE THERMODYNAMIC AND ENVIRONMENTAL ANALYSIS OF VAPOR COMPRESSION REFRIGERATION SYSTEM USING C-PENTANE AS REFRIGERANT

The selection of refrigerant is one of the most important parameters when designing a cooling system. Hydrocarbon refrigerants have low primary energy requirements for effective cooling capacity and favourable thermodynamic properties that reduce both direct and indirect greenhouse gas emissions. In this study, a comparative performance and environmental analysis of the vapor compression refrigeration cycle using C-Pentane as the refrigerant was performed. The cooling performance and environmental effect of C-Pentane has been compared with the cooling performance and environmental effect of R134A, R407C and R404A refrigerants in the cooling system. During the analysis, the cooling system was examined under different operating conditions. The highest coefficient of performance (COP) value in the analysis was 6.485 for the refrigeration cycle using C-Pentane, and this value was obtained at 0 oC evaporator temperature and 25 oC condenser temperature operating condition. According to the Life Cycle Climate Performance (LCCP) analysis for refrigerants, the lowest total emission value belongs to C-Pentane. Direct Emission (DE) value and indirect emission (IE) value of C-Pentane are 57.5 kgCO2 and 24928.04 kgCO2, respectively.

IoT-driven monitoring and controlling to improve performance of thermoelectric air conditioning system

Thermoelectric module-based air conditioners (TEM-AC) are scalable, reliable, and have the potential to replace conventional air conditioners. However, the coefficient of performance (COP) of TEM-AC is still relatively low. Improving the COP requires a combination of temperature control, voltage control, heat recovery, airflow control, and material selection. The present study focuses on enhancing COP of the TEM-AC for building space cooling. To control and monitor the parameters of the TEM-AC, a low-cost, IoT-enabled monitoring and controlling system (MCS) is developed. The MCS helps in TEM-AC system designing as it can apply different current pulses to improve cooling capacity and control the temperature difference between both surfaces. MCS also measure all the required parameters of the TEM-AC to calculate the COP of the system and helps in reducing the calculation time for each experiment. Using a developed technique and TEM-AC design, a performance comparison of eight experimental cases has been done. Experiments have been performed in normal and control modes with different heat sinks and airflow of TEM-AC. The TEM-AC system is installed over a 16-inch × 12-inch enclosed space with a TEC-12706 module. The study indicates the COP of the system is enhanced by controlling the cold side temperature and air flow rate. For this study, maximum COP is achieved around 0.44 with control operation. The developed IoT-based monitoring and controlling system offers a promising solution for improving the performance of thermoelectric modules in building space conditioning applications.

Effect of salt on the performance of ammonia absorption refrigeration cycle: A simulation study

To overcome the drawbacks associated with conventional binary mixtures (NH3-H2O and H2O-LiBr) in the vapor absorption refrigeration system (VARS), salt is added to the NH3-H2O mixture. The present simulation study analyzes the influence of adding LiBr and LiNO3 salts within a salt mass fraction range of 0 to 35% on the coefficient of performance (COP) of the NH3-H2O cycle. The simulations are conducted using Aspen Plus software. Furthermore, the influence of generator temperature on the COP and evaporator capacity of the ternary NH3-H2O-LiBr and NH3-H2O-LiNO3 cycles are also studied. The simulation results demonstrate that adding LiBr and LiNO3 salts improves the COP and reduces the initial temperature requirement in the generator of the VARS. Specifically, the NH3-H2O-LiBr cycle achieves the highest COP of 0.645 at an NH3 mass fraction of 55% and a LiBr mass fraction of 25%. This represents an 8.81% improvement compared to the COP of the NH3-H2O cycle. Similarly, the NH3-H2O-LiNO3 cycle exhibits the peak COP of 0.603 with the same NH3 mass fraction and LiNO3 mass fraction of 20%, which is 2.2% greater than the COP of the NH3-H2O cycle. Under similar operating conditions, the COP of the NH3-H2O-LiBr cycle is greater than that of the NH3-H2O-LiNO3 cycle.

Energy characteristics of multi-chiller load distribution algorithms in a large office building

This study evaluates the energy efficiency of multi-chiller systems in large office buildings, focusing on their optimization across various climate zones as defined by ASHRAE. Using EnergyPlus for simulations, the research examines five different load distribution algorithms in multi-chiller systems that range from one to ten chillers, aiming to understand their effectiveness in 15 distinct climate zones. The primary objectives of the study include identifying the energy efficiency of multi-chiller systems in each climate zone, determining the appropriate number of chillers for each zone, and evaluating the performance of the load distribution algorithms. Based on the U.S. Department of Energy’s commercial building model, the results suggest that multi-chiller systems can significantly reduce cooling energy consumption in various climates. Among the algorithms evaluated, the Sequential Uniform Part Load Ratio (SUPLR) algorithm demonstrates notable efficiency, especially in the 4A climate zone (Baltimore), where it achieves substantial energy savings. Applying the SUPLR algorithm in a multi-chiller setup with four chillers in this zone leads to an estimated 24.5 % reduction in energy usage, equivalent to 183 MW annually. The research indicates that a range of 3 to 5 chillers is typically optimal for most climate zones. In-depth analysis in the 4A climate zone highlights the importance of minimizing operation hours at low Part Load Ratios (PLR) to ensure that chillers operate at a high Coefficient of Performance (COP). This strategy underscores the potential of well-designed multi-chiller systems to reduce cooling energy demand, particularly in climates with transitional seasons. This study provides an overview of the energy-saving potential of multi-chiller systems, applicable across a variety of climatic scenarios.

Design of New Heat Pump Dryer System: A Case Study in Drying Characteristics of Kitchen Waste

Existing kitchen waste treatment equipment primarily employs biological cultures for high-temperature fermentation of kitchen waste during the secondary decomposition stage. The temperature inside the fermentation chamber is mainly achieved by heating the air through electric heating tubes. However, this method of electric heating still possesses numerous shortcomings, such as high power consumption and significant energy loss. Given the aforementioned reasons, this article proposes a heat pump drying device specifically designed for the moisture removal process during the fermentation treatment of kitchen waste. This device effectively removes the moisture generated during the fermentation of kitchen waste and assists the electric heating unit in the biomass waste treatment equipment in heating the fermentation chamber, thereby reducing electricity consumption.The closed-loop heat pump drying system can continuously introduce hot, low-humidity air into the fermentation chamber through a circulating fan to remove moisture from kitchen waste.To investigate the dehumidification performance of this device, this article varies the airflow rate of the circulating fan in the heat pump drying system and the inlet water temperature of the plate heat exchanger, achieving changes in the airflow through the dehumidification evaporator and the condensation temperature of the system. Under experimental conditions, the range of the coefficient of performance (COP) achieved by the device is between 3.07 and 5.39; the specific moisture extraction rate (SMER) ranges from 0.62 to 1.81 Kg/(Kw·h), and the moisture removal rate (Mr) ranges from 1.9 Kg/h to 8.2 Kg/h.

Thermal performance of two-independent-circuit borehole heat exchanger in solar-assisted ground source heat pump system

The Two-Independent-Circuit Borehole Heat Exchanger (TICBHE) has become the focus of attention, partly due to the potential to reduce system complexity of circulating fluid loops and increase the system performance of the traditional Solar-assisted Ground Source Heat Pump (SGSHP) system. However, the ground was usually regarded as homogeneous media, limited research has been conducted on the effect of the geological stratification on the SGSHP system with TICBHE. Therefore, a numerical model of TICBHE is firstly established and validated by relevant experiments, and its thermal performance is analyzed and investigated. Additionally, the thermal performance of the TICBHE is compared and analyzed with different independent systems including the Photovoltaic-Thermal (PVT) Coupled with Single U-pipe Borehole (SUBPVT) system and Heat Pump Coupled with Single U-pipe Borehole (SUBHP) system. The results show that the difference between the inlet and outlet water temperatures of the Heat Source (HS) and the Heat Pump (HP) circuit in the SGSHP system is respectively increased by 0.6 °C and 0.1 °C. The total heat injection of the SGSHP system is 417.2 kWh, 19.7% higher than that of the SUBPVT system. The total heat extraction of the SGSHP system is 457.8 kWh, a 2% increase compared with the SUBHP system in the 12-day operation. Moreover, the whole power generation of the SGSHP system is 4.4% higher than that of the uncooled PVT collectors. The average Coefficient of Performance (COP) of the heat pump in the SGSHP system is 7.7% higher than that of the SUBHP system in the 12-day operation.

Thermal performance of three-wheel and split-wheel air cycle systems for a civil aircraft environmental control system (ECS)

The conventional approach of regulating cabin temperature and pressure on aircraft is to utilize engine-bleed air through an environmental control system (ECS). The extraction of bleed air from the engine leads to a decrease in thrust and an increase in drag on the ECS ram air duct, resulting in higher fuel consumption. Consequently, the ECS transitioned from being engine-powered to being electrically powered. In this study, the thermodynamic characteristics of three-wheel and split-wheel air cycle systems (ACSs) with a high-pressure water separation system (HPWS) were investigated by developing a parameter decomposition model and an iterative algorithm using MATLAB for a state-of-the-art electrically driven ECS (EECS) on the Boeing 787 Dreamliner. The efficiency of the ACS was assessed by establishing analytical correlations for the coefficient of performance (COP) using relevant literature on endo-reversible thermodynamic model (ETM). By employing these analytical correlations, the thermal performance of both ACSs can be accurately predicted without the need for system modeling and simulation, considering variations in the input variables and operating conditions, such as the temperatures of fresh air and ram air, the ratio of the mass flow rates of ram air and fresh air, and component parameters, including the efficiencies of the primary and secondary heat exchangers and the pressure ratios of the fan and compressor. The implementation of a split-wheel ACS instead of three-wheel ACS in the Boeing 787 EECS led to an improvement in the COP from 0.31 to 0.43, and also resulted in a reduction of 14.35 % in the input power.

Thermodynamic analysis and optimization of hydrogen liquefaction system with binary refrigerant precooling cycle

A hydrogen liquefaction process is proposed with the liquid natural gas utilization, binary refrigerant precooling and helium cryogenic cycles combined, and a general model is built for analyzing the variation of hot and cold composite curves and heat transfer temperature difference (HTTD) along with refrigerant parameters. The relationship between temperature and enthalpy of the precooling cycle and the variation of HTTD are deduced. Based on this, the composite curves and HTTD curves are constructed, and the influence of refrigerant on the HTTD and the refrigerant outlet temperature is analyzed. The optimization procedure of refrigerant is proposed based on the temperature-enthalpy relationship and HTTD considering the temperature glide. For the proposed hydrogen liquefaction system, the optimal binary refrigerant includes 60.21 % nitrogen and 39.79 % propane (mass fraction), and its mass flow rate and inlet temperature are 23,821.96 kg/h and −199.72 °C, respectively. The corresponding specific energy consumption (SEC) of the hydrogen liquefaction system is 4.44 kWh/kgLH2, reduced by 10.30 %, and the coefficient of performance (COP) and exergy efficiency are 27.10 % and 28.26 %, increased by 11.34 % and 17.80 %, respectively.

Performance analysis of double-stage heat pump and refrigeration cycles

Multistage refrigeration systems are investigated to/enhance the performance of vapor compression refrigeration cycles based on our previous work on multistage low-grade thermal energy conversion. A double-stage heat pump and refrigeration cycles (D-S) is expected to reduce the irreversible loss in the heat exchange process. However, certain characteristics of independently configured systems, namely, compressor power and coefficients of performance (COPs), have not been sufficiently clarified. This study aims to elucidate highly advanced heat pump and refrigeration systems by comparing D-S, a basic single-stage heat pump and refrigeration cycles, and a two-stage compression cycle. D-S shows higher COPs for both the refrigeration and heat pump cycles compared with the other cycles, especially at high thermal conductances. The reduction of the irreversible loss in the heat exchange process is confirmed via the entropy generation rate; in particular, the COP increases with a decrease in the entropy generation rate. The evaporation and condensation temperatures of the refrigerant approach the temperature of the heat source when the thermal conductance exceeds 150 kW/K for the refrigeration cycle. The heat exchangers exergy destruction of D-S is 169 kW, S-S is 189 kW, the two-stage cycle is 184 kW/K when the thermal conductance is 100 kW/K.

Thermal Performance Design and Analysis of Reversed Brayton Cycle Heat Pumps for High-Temperature Heat Supply

This study examined the performance of reversed Brayton cycle heat pumps to supply heat above 300 °C. The aim was to overcome the current temperature limitations faced by heat pump technology in industrial heat supply sectors by examining the viability of the reversed Brayton cycle. In particular, the effects of the operating conditions on the cycle performance, such as the waste and return heat temperatures, were analyzed through thermal performance analysis. The reversed Brayton cycle heat pumps showed improved performance over conventional vapor compression cycle heat pumps when a heat supply above 215 °C was required. Furthermore, integrating additional heat exchangers into the cycle configuration was proposed in this study as a method to enhance waste heat utilization and recover unused heat from industrial processes. By incorporating preheating and recuperated cycles, these modifications broaden the operational range under the same operating conditions. They also improve the coefficient of performance (COP) of the reference cycle by up to 23% and 27.4%, respectively. This study explored the potential of reversed Brayton cycle heat pumps to supply heat above 300 °C and provided fundamental guidelines for the efficient design and operation of reversed Brayton cycle heat pumps. The results are expected to enhance our understanding of the performance characteristics of reversed Brayton cycle heat pump technology and expand its use as an alternative to fossil-fuel-based heat supply systems.

Application of artificial neural networks in predicting the performance of ice thermal energy storage systems

Efficient prediction of thermal system performance is crucial for optimizing building energy systems. This paper introduces a predictive model to forecast Heating, Ventilation, and Air Conditioning (HVAC) systems' performance with Ice Thermal Energy Storage (ITES). The indicators encompass storage temperature, Coefficient of Performance (COP), cooling thermal load, and chiller power consumption. These forecasts play a pivotal role in cost-effective experimentation, energy optimization, reduced consumption, and minimized operational costs. The study focuses on developing an Artificial Neural Network (ANN) model using a shallow Neural Net Fitting application (nftool). This ANN model predicts necessary ITES system configurations based on nonlinear input variables. Utilizing a comprehensive dataset, incorporating dry bulb temperature, component inlet and outlet temperatures, flow rates, and control valve states, the ANN model is built and validated. Performance metrics, including Mean Squared Errors (MSE) and Regression (R), are employed for training, validation, and testing to predict individual configurations. The results reveal R values ranging from 0.94 to 0.99, with MSE mostly below 20 %. This study exemplifies machine learning's application to ITES cooling systems, serving as a benchmark for evaluating ANN methodologies' effectiveness in prediction. It sheds light on parameter variation's impact on ITES cooling systems and underscores ANN's accuracy in predicting HVAC system parameters with ITES.

Investigation on a heat-driven thermoacoustic refrigerator with minimal complexity

Heat-driven thermoacoustic refrigerator (HDTR) emerges as a pivotal solution to global energy challenges and carbon emissions. This study introduces a simplified single-unit HDTR as a new supplement to the heat-driven thermoacoustic refrigeration process. Featuring only one simple, direct-coupled thermoacoustic energy conversion core unit, it is designed to reduce overall system complexity. Initially, the simulation model of the single-unit system is established in Sage and compared with a two-unit HDTR, indicating that reducing the number of thermoacoustic core units decreases system complexity without compromising system performance. The onset characteristics and steady-state operational characteristics of the proposed single-unit HDTR are then experimentally tested, revealing a cooling power of 895 W with a coefficient of performance (COP) of 0.43 when the ambient and cooling temperature is 25 °C and 0 °C, respectively. Notably, a minimal onset temperature difference of 61.6 °C is obtained for the single-unit HDTR. These results showcase the possible application potential for low-grade heat recovery. A comparative analysis against existing loop HDTR systems establishes its superior performance, offering a valuable reference for contemporary HDTR assessments. This study significantly advances HDTR development, emphasizing efficiency and sustainable cooling applications.

Research on the matching relationship of multi-energy collaborative temperature control in factory farming system based on TRNSYS

In light of the escalating energy crisis and the imperative to address climate change, there exists a pervasive global consensus advocating the reduction of carbon emissions and the exploration of novel energy sources. Despite this consensus, the realm of factory farming continues to rely upon conventional energy sources for heating purposes. This study focuses on the investigation into the multi-energy heating system employed by an aquaculture company in Dalian City. We undertook the optimization of critical parameters within this system and formulate a comprehensive model for the multi-energy system using the TRNSYS transient simulation platform. The optimization process employs the Hooke-Jeeves algorithm, implemented through GenOpt software, with the system annual value cost serving as the objective function. Optimization variables include solar collector area, solar collector slope, thermal storage tank volume, seawater source heat pump power, and wastewater plate heat exchanger area. The findings of this investigation reveal a marked enhancement in the Coefficient of Performance (COP) and overall system performance after optimization. The resultant annual operating cost was $3133.61, indicating a substantial reduction of $1151.86 compared to the pre-optimization period’s cost. The static payback period is determined to be 9.43 years. During the heating period, in contrast to traditional boiler heating, the optimized system manifests a reduction in coal consumption of 4485.03 kg, accompanied by a cumulative decrease in pollutant emissions totaling 11544.46 kg. This substantiates the system’s cumulative economic and environmental viability.

LOW-COST OPERATING LPG REFRIGERATOR SYSTEM

The study explores the use of liquefied petroleum gas (LPG) as a refrigerant in domestic refrigerators to provide continuous refrigeration in areas without steady electricity supply. LPG, consisting of propane, butane, and isobutene, is cost-effective and environmentally friendly with no Ozone Depletion Potential or Global Warming Potential. The experiment compared the performance of an LPG-based refrigerator to one using R134a, finding LPG to be more efficient. By analyzing the refrigeration effect over time, the study determined the optimum cooling effect based on valve and capillary tube settings. LPG undergoes a phase change in the capillary tube, resulting in a drop in pressure and temperature, allowing it to produce a refrigerating effect. The Coefficient of Performance (COP) of an LPG refrigerator was found to be higher than a traditional refrigerator. Overall, using LPG as a refrigerant in refrigerators can be a sustainable and environmentally friendly solution for regions with unreliable electricity access. Key Words: LPG, REFRIGERATOR, REFRIGERANT, OZONE DEPLETION POTENTIAL.

4E analysis of a solar, wind and waste heat-driven CCHP system: A case study for a cruise ship

One of the most advanced technologies for meeting all cooling, heating, and electrical demands is Combined Cooling Heating and Power (CCHP) systems. This paper proposes using PV panels, wind turbines, and CCHP system based on an Organic Rankine Cycle integrated absorption chiller, for a cruise ship MS Birka Stockholm. A part of the electricity demand is provided by three wind turbines and PV panels, and another part is generated by the CCHP system. The proposed CCHP system works by recovering heat by three main engines in summer and mid-season and four main engines in winter. It’s important to mention that in actual condition the ship is working with eight engines. Decreasing the number of engines and using renewable energies could be a very alluring issue in the transportation systems. Energy, Exergy, Exergoeconomic, and exergoenvironmental (4E) analysis is done for the system and also components with the highest exergy destruction and cost rate and environmental effects are recognized. 4E analysis could give the researchers opportunity to compare their proposed systems results, that is never done in this field. Mentioned analysis are divided into three parts, including winter, mid-season and summer. For the summer, energy and exergy efficiencies are 65% and 40.13%, respectively. The coefficient of performance (COP) is also calculated 0.706. For mid-season, thermal efficiency is calculated 97.4% and exergy efficiency is calculated 24.31%. Therefore, for winter thermal efficiency is calculated 98% and exergy efficiency is calculated 9.3%. The cost associated with total exergy destruction is 1,193,099 €/year, and the total investment cost of the system is 179,592 €/year. The total environmental impacts associated with the exergy destruction and the total value of the component-related environmental impact of the system (Ẏ) were calculated as 2,479,713 mpts/year and 864,627mpts/year, respectively.

Selection of pure and binary working fluids for high-temperature heat pumps: A financial approach

High-temperature heat pumps are increasingly being recognized for decarbonizing industrial heat supply up to 200 °C. In the open literature, the operating conditions, working fluids and configurations of high-temperature heat pumps are typically optimized for achieving a maximum Coefficient of Performance (COP). This work however presents a method that optimizes the operating conditions, working fluid and configuration of the heat pump, based on a combined financial and technical appraisal. In this regard a financial model to calculate the levelized cost of heat (LCOH) of a heat pump unit is developed. The model screens a large set of working fluids and therefore allows for subcritical, transcritical and supercritical operation and includes (zeotropic) binary mixtures. The methodology is applied to a large set of generic temperature profiles, with process temperatures between 160 °C and 200 °C and heat source temperatures between 80 °C and 120 °C. The results indicate that designing a heat pump solely based on maximum COP may lead to a sub-optimal financial solution. Overall, binary mixtures, either zeotropic or azeotropic, of natural working fluids often performed best. The benefits of zeotropic mixtures are twofold: improved temperature matching and flexibility in their thermophysical properties. However, for industrial processes with high temperature glides, pure fluids operating in the transcritical regime proved to be the most promising. The study also highlights the sensitivity of the financial performance to the electricity price, annual operating hours and heating capacity.

Thermodynamic optimization of heat exchanger circuitry via genetic programming

In this study, an evolutionary thermodynamic technique was developed for the optimization of heat exchanger circuitry. The proposed technique is capable of handling the unrestrained implementation of genetic operators while ensuring circuitry feasibility and basic manufacturability. The optimization tool was used to clarify the optimal heat transfer features in relation to the characteristics of the refrigerant and to provide a thermodynamic interpretation of the optimization results to extract general design guidelines. Evaporator circuitry optimization was conducted under given cooling capacity, superheating degree, and boundary conditions representative of air-conditioning applications. The consistency between the minimum entropy generation and the maximum coefficient of performance (COP) was demonstrated under these settings. Accordingly, heat exchanger configurations that take maximum advantage of the thermodynamic benefits of each refrigerant are proposed by optimizing the distribution of friction and heat transfer irreversibility. Consequently, the evaporator outlet pressure increases, thus lowering the compression ratio and maximizing the COP. The developed optimization method maximizes the benefits of low-GWP alternative refrigerants and shows that zeotropic mixtures may exhibit performance analogous to that of R32 and higher than that of R410A by approaching a Lorenz cycle operation.

Efficient portable thermoelectric refrigerator developed with a temperature control system mode at best COP for different seasons and conditions of the year

ABSTRACT Global energy scarcity and pollution resulting from excessive energy consumption are among the most important causes of global warming, in addition to using Freon, which poses a danger to the environment. This led to searching for sustainable alternatives that use less energy to alleviate environmental difficulties and are eco-friendly. The portable thermoelectric refrigerator was developed to control the temperature required in different seasons of the year, for those who live in rural areas in Egypt (such as deserts). The main control unit has five modes (Economic, Minimum, Medium, Fast and Fast not Economic) based on the best coefficient of performance (COP) and minimum energy. The results showed the highest COP, for the economic mode with an 8°C difference in temperature, and the lowest COP with a 26.4°C difference in temperature for the fast not economic mode. On the other hand, the difference temperatures of 12.5°C,18.2°C and 23°C of the mode minimum, medium and, fast, respectively.

Optimization of Triple Effect Vapour Absorption Refrigeration System: A Statistical Approach

Abstract The present manuscript optimized the First and Second Law performance of the triple effect vapour absorption refrigeration systems (TE-VARS) using statistical techniques like Taguchi, Taguchi-based GRA, and RSM-based GRA methods, which provide the most accurate and optimized results. Liquified pertrolium gas (LPG) and Compressed natural gas (CNG) are considered as the source of energy to operate TE-VARS, as the system requires significantly higher generator temperature. Also, volume flow rate of these gases along with the annual operating cost to drive the system have been presented. A thermodynamic model was first formulated using EES software for the computation of the coefficient of performance (COP) and exergetic efficiency (ECOP). The most influential parameters like temperature in the main generator, concentration and pressure at different components are studied and determined using ANOVA and Taguchi methods. The optimum parameters were determined based on the mean effect plot of S/N ratios for COP and ECOP. It has been found that the maximum COP and ECOP were calculated to be 1.915 and 0.15, respectively under the Taguchi method. Furthermore, Taguchi-GRA was used for the simultaneous optimization of the operating parameters and performance of the system. It is observed that the absorber temperature is the most influential parameter for affecting COP and ECOP. Moreover, a RSM-based GRA method was also applied and developed regression models that yield most optimum COP and ECOP as 1.963 and 0.1606, respectively. Comparison shows that the RSM-based GRA method provide the most optimum conditions, which is one of the key finding of the present study. Also, rate of exergy destruction at each component of TE-VARS has been plotted under optimized operating conditions. The optimum volume flow rate for LPG and CNG comes out to be 0.057 and 0.177 m3/s, while the minimum operating cost (yearly) are 299.827$ and 183.293$, respectively.