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This paper presents the thermodynamic analysis, performance assessment and working fluid selection for a novel integrated vapor compression cycle and the organic Rankine cycle system, which recovers ultra-low-temperature waste heat (50 °C) rejected by the condenser of a vapor compression cycle (VCC). The study is conducted on a vapor compression system of a 35 kW cooling capacity, followed by the component sizing of the organic Rankine cycle (ORC) based on the available waste heat in the condenser of the refrigeration system. The effect of the operational parameters of the vapor compression cycle on the overall system performance are investigated. The system performance of the integrated system is estimated in terms of coefficient of performance, cycle thermal efficiency and exergy efficiency. The novel integrated systems has been analyzed thermodynamically for 36 pairs of pure refrigerants. Results show that the working fluid pair R600a/R141b with combined coefficient of performance (3.54), ORC thermal efficiency (3.05 %), electricity saving ratio (13.34 %) and total exergy destruction (6.94 kW) is the most suitable VCC/ORC working fluid pair in full condensing method. R407c-R141b is found to be the best working fluid pair in desuperheating method for the same integrated system. The performance analysis for full condensation and desuperheating methods are also investigated. The results indicate a 12.5 % improvement in the coefficient of performance of the integrated system using the full condensation method and a 2.5 % improvement using the desuperheating method compared to the standalone air conditioning system. Additionally, the sensitivity analysis results show that there exists optimum operating condition that maximize the system performance of the integrated system. © 2024 The Author(s)

This experimental investigation related with the performance evaluation of a refrigeration system by using variouseco friendly refrigerant mixtures. The refrigeratingsystem used for the evaluation works on(VCC) vapor compression cycleon the principle of heat is absorbed in anevaporator by evaporation process. Now days it is very important to increase the coefficient of performance (COP)of the refrigeration system and to increase the COP lot of researches are done.The eco friendly refrigerants used in the system to enhance the performance are R134a (Tetrafluoroethane), R290 (Isobutane).This experimental study contracts with a comparative analysis of the performance of variousmixtures of refrigerantsas described below with R134a kept as a comparative parameter. The above refrigerants are mixed on the basis on weight proportions in diverseratios, and below mentionedmixtures used are:Test-1: R134aTest-2: R134a -80% and R290 -20%

This experimental investigation related with the performance evaluation of a refrigeration system by using variouseco friendly refrigerant mixtures. The refrigeratingsystem used for the evaluation works on(VCC) vapor compression cycleon the principle of heat is absorbed in anevaporator by evaporation process. Now days it is very important to increase the coefficient of performance (COP)of the refrigeration system and to increase the COP lot of researches are done.The eco friendly refrigerants used in the system to enhance the performance are R134a (Tetrafluoroethane), R290 (Isobutane).This experimental study contracts with a comparative analysis of the performance of variousmixtures of refrigerantsas described below with R134a kept as a comparative parameter. The above refrigerants are mixed on the basis on weight proportions in diverseratios, and below mentionedmixtures used are:Test-1: R134aTest-2: R134a -80% and R290 -20%

This experimental investigation related with the performance evaluation of a refrigeration system by using variouseco friendly refrigerant mixtures. The refrigeratingsystem used for the evaluation works on(VCC) vapor compression cycleon the principle of heat is absorbed in anevaporator by evaporation process. Now days it is very important to increase the coefficient of performance (COP)of the refrigeration system and to increase the COP lot of researches are done.The eco friendly refrigerants used in the system to enhance the performance are R134a (Tetrafluoroethane), R290 (Isobutane).This experimental study contracts with a comparative analysis of the performance of variousmixtures of refrigerantsas described below with R134a kept as a comparative parameter. The above refrigerants are mixed on the basis on weight proportions in diverseratios, and below mentionedmixtures used are:Test-1: R134aTest-2: R134a -80% and R290 -20%

This experimental investigation related with the performance evaluation of a refrigeration system by using variouseco friendly refrigerant mixtures. The refrigeratingsystem used for the evaluation works on(VCC) vapor compression cycleon the principle of heat is absorbed in anevaporator by evaporation process. Now days it is very important to increase the coefficient of performance (COP)of the refrigeration system and to increase the COP lot of researches are done.The eco friendly refrigerants used in the system to enhance the performance are R134a (Tetrafluoroethane), R290 (Isobutane).This experimental study contracts with a comparative analysis of the performance of variousmixtures of refrigerantsas described below with R134a kept as a comparative parameter. The above refrigerants are mixed on the basis on weight proportions in diverseratios, and below mentionedmixtures used are:Test-1: R134aTest-2: R134a -80% and R290 -20%

This experimental investigation related with the performance evaluation of a refrigeration system by using variouseco friendly refrigerant mixtures. The refrigeratingsystem used for the evaluation works on(VCC) vapor compression cycleon the principle of heat is absorbed in anevaporator by evaporation process. Now days it is very important to increase the coefficient of performance (COP)of the refrigeration system and to increase the COP lot of researches are done.The eco friendly refrigerants used in the system to enhance the performance are R134a (Tetrafluoroethane), R290 (Isobutane).This experimental study contracts with a comparative analysis of the performance of variousmixtures of refrigerantsas described below with R134a kept as a comparative parameter. The above refrigerants are mixed on the basis on weight proportions in diverseratios, and below mentionedmixtures used are:Test-1: R134aTest-2: R134a -80% and R290 -20%

This experimental investigation related with the performance evaluation of a refrigeration system by using variouseco friendly refrigerant mixtures. The refrigeratingsystem used for the evaluation works on(VCC) vapor compression cycleon the principle of heat is absorbed in anevaporator by evaporation process. Now days it is very important to increase the coefficient of performance (COP)of the refrigeration system and to increase the COP lot of researches are done.The eco friendly refrigerants used in the system to enhance the performance are R134a (Tetrafluoroethane), R290 (Isobutane).This experimental study contracts with a comparative analysis of the performance of variousmixtures of refrigerantsas described below with R134a kept as a comparative parameter. The above refrigerants are mixed on the basis on weight proportions in diverseratios, and below mentionedmixtures used are:Test-1: R134aTest-2: R134a -80% and R290 -20%

This experimental investigation related with the performance evaluation of a refrigeration system by using variouseco friendly refrigerant mixtures. The refrigeratingsystem used for the evaluation works on(VCC) vapor compression cycleon the principle of heat is absorbed in anevaporator by evaporation process. Now days it is very important to increase the coefficient of performance (COP)of the refrigeration system and to increase the COP lot of researches are done.The eco friendly refrigerants used in the system to enhance the performance are R134a (Tetrafluoroethane), R290 (Isobutane).This experimental study contracts with a comparative analysis of the performance of variousmixtures of refrigerantsas described below with R134a kept as a comparative parameter. The above refrigerants are mixed on the basis on weight proportions in diverseratios, and below mentionedmixtures used are:Test-1: R134aTest-2: R134a -80% and R290 -20%

This experimental investigation related with the performance evaluation of a refrigeration system by using variouseco friendly refrigerant mixtures. The refrigeratingsystem used for the evaluation works on(VCC) vapor compression cycleon the principle of heat is absorbed in anevaporator by evaporation process. Now days it is very important to increase the coefficient of performance (COP)of the refrigeration system and to increase the COP lot of researches are done.The eco friendly refrigerants used in the system to enhance the performance are R134a (Tetrafluoroethane), R290 (Isobutane).This experimental study contracts with a comparative analysis of the performance of variousmixtures of refrigerantsas described below with R134a kept as a comparative parameter. The above refrigerants are mixed on the basis on weight proportions in diverseratios, and below mentionedmixtures used are:Test-1: R134aTest-2: R134a -80% and R290 -20%

This experimental investigation related with the performance evaluation of a refrigeration system by using variouseco friendly refrigerant mixtures. The refrigeratingsystem used for the evaluation works on(VCC) vapor compression cycleon the principle of heat is absorbed in anevaporator by evaporation process. Now days it is very important to increase the coefficient of performance (COP)of the refrigeration system and to increase the COP lot of researches are done.The eco friendly refrigerants used in the system to enhance the performance are R134a (Tetrafluoroethane), R290 (Isobutane).This experimental study contracts with a comparative analysis of the performance of variousmixtures of refrigerantsas described below with R134a kept as a comparative parameter. The above refrigerants are mixed on the basis on weight proportions in diverseratios, and below mentionedmixtures used are:Test-1: R134aTest-2: R134a -80% and R290 -20%

This experimental investigation related with the performance evaluation of a refrigeration system by using variouseco friendly refrigerant mixtures. The refrigeratingsystem used for the evaluation works on(VCC) vapor compression cycleon the principle of heat is absorbed in anevaporator by evaporation process. Now days it is very important to increase the coefficient of performance (COP)of the refrigeration system and to increase the COP lot of researches are done.The eco friendly refrigerants used in the system to enhance the performance are R134a (Tetrafluoroethane), R290 (Isobutane).This experimental study contracts with a comparative analysis of the performance of variousmixtures of refrigerantsas described below with R134a kept as a comparative parameter. The above refrigerants are mixed on the basis on weight proportions in diverseratios, and below mentionedmixtures used are:Test-1: R134aTest-2: R134a -80% and R290 -20%

This experimental investigation related with the performance evaluation of a refrigeration system by using variouseco friendly refrigerant mixtures. The refrigeratingsystem used for the evaluation works on(VCC) vapor compression cycleon the principle of heat is absorbed in anevaporator by evaporation process. Now days it is very important to increase the coefficient of performance (COP)of the refrigeration system and to increase the COP lot of researches are done.The eco friendly refrigerants used in the system to enhance the performance are R134a (Tetrafluoroethane), R290 (Isobutane).This experimental study contracts with a comparative analysis of the performance of variousmixtures of refrigerantsas described below with R134a kept as a comparative parameter. The above refrigerants are mixed on the basis on weight proportions in diverseratios, and below mentionedmixtures used are:Test-1: R134aTest-2: R134a -80% and R290 -20%

This experimental investigation related with the performance evaluation of a refrigeration system by using variouseco friendly refrigerant mixtures. The refrigeratingsystem used for the evaluation works on(VCC) vapor compression cycleon the principle of heat is absorbed in anevaporator by evaporation process. Now days it is very important to increase the coefficient of performance (COP)of the refrigeration system and to increase the COP lot of researches are done.The eco friendly refrigerants used in the system to enhance the performance are R134a (Tetrafluoroethane), R290 (Isobutane).This experimental study contracts with a comparative analysis of the performance of variousmixtures of refrigerantsas described below with R134a kept as a comparative parameter. The above refrigerants are mixed on the basis on weight proportions in diverseratios, and below mentionedmixtures used are:Test-1: R134aTest-2: R134a -80% and R290 -20%

A computationally efficient but accurate dynamic modeling approach for vapor compression systems is important for many applications. Nonlinear model order reduction techniques which generate reduced order models based on high fidelity vapor compression cycle (VCC) models are attractive for the purposes. In this paper, a number of technical challenges of applying model order reduction methods to VCCs are described and corresponding solution approaches are presented. It starts with a reformulation of a standard finite volume heat exchanger model for matching the baseline model reduction structure. Reduced order models for evaporator and condenser are constructed from numerical snapshots of the high fidelity models using Proper Orthogonal Decomposition (POD). Methodologies for system stability and numerical efficiency of POD reduced order models are described. The reduced order heat exchanger models are then coupled with quasi-static models of other components to form a reduced order cycle model. Transient simulations were conducted over a wide range of operating conditions and results were compared with the full order model as well as measurements. The validation results indicate that the reduced order model can execute much faster than a high-fidelity finite volume model with negligible prediction errors.

A computationally efficient but accurate dynamic modeling approach for vapor compression systems is important for many applications. Nonlinear model order reduction techniques which generate reduced order models based on high fidelity vapor compression cycle (VCC) models are attractive for the purposes. In this paper, a number of technical challenges of applying model order reduction methods to VCCs are described and corresponding solution approaches are presented. It starts with a reformulation of a standard finite volume heat exchanger model for matching the baseline model reduction structure. Reduced order models for evaporator and condenser are constructed from numerical snapshots of the high fidelity models using Proper Orthogonal Decomposition (POD). Methodologies for system stability and numerical efficiency of POD reduced order models are described. The reduced order heat exchanger models are then coupled with quasi-static models of other components to form a reduced order cycle model. Transient simulations were conducted over a wide range of operating conditions and results were compared with the full order model as well as measurements. The validation results indicate that the reduced order model can execute much faster than a high-fidelity finite volume model with negligible prediction errors.

This experimental investigation related with the performance evaluation of a refrigeration system by using variouseco friendly refrigerant mixtures. The refrigeratingsystem used for the evaluation works on(VCC) vapor compression cycleon the principle of heat is absorbed in anevaporator by evaporation process. Now days it is very important to increase the coefficient of performance (COP)of the refrigeration system and to increase the COP lot of researches are done.The eco friendly refrigerants used in the system to enhance the performance are R134a (Tetrafluoroethane), R290 (Isobutane).This experimental study contracts with a comparative analysis of the performance of variousmixtures of refrigerantsas described below with R134a kept as a comparative parameter. The above refrigerants are mixed on the basis on weight proportions in diverseratios, and below mentionedmixtures used are:Test-1: R134aTest-2: R134a -80% and R290 -20%

This experimental investigation related with the performance evaluation of a refrigeration system by using variouseco friendly refrigerant mixtures. The refrigeratingsystem used for the evaluation works on(VCC) vapor compression cycleon the principle of heat is absorbed in anevaporator by evaporation process. Now days it is very important to increase the coefficient of performance (COP)of the refrigeration system and to increase the COP lot of researches are done.The eco friendly refrigerants used in the system to enhance the performance are R134a (Tetrafluoroethane), R290 (Isobutane).This experimental study contracts with a comparative analysis of the performance of variousmixtures of refrigerantsas described below with R134a kept as a comparative parameter. The above refrigerants are mixed on the basis on weight proportions in diverseratios, and below mentionedmixtures used are:Test-1: R134aTest-2: R134a -80% and R290 -20%

Heat pumps are increasingly being installed in domestic buildings, which is an opportunity to reduce the energy needed to heat and cool buildings. However, this reduction will only be possible if the equipment is maintained correctly. Fault detection and diagnosis (FDD) systems can improve the cost of operating and maintaining heating and air conditioning systems, specifically heat pump, while keeping their performance. This article first briefly introduces the methodologies used in FDD systems for heat pumps and compare their performance. Then, an accurate description of the common faults and their effects on field vapor compression systems is made. After that, a compilation of which faults and how are emulated in both laboratory conditions and virtual environments are extensively described. The measurements needed to perform the diagnosis are analyzed along with instrumentation needed for FDD systems. Finally, the virtual sensors applied to heat pumps to reduce the cost associated with FDD implementation are described. This article aims to establish a criterion for selecting which faults can be tested under laboratory conditions or by simulation with a virtual model and to determine the features that identify those faults. Finally, several areas of improvement for the aspects reviewed have been identified: increase the use of performance indicators for FDD, new and updated studies about the health status of field heat pumps, testing methods that take into account the gradual and probabilistic nature of heat pump faults and further research in the use of virtual sensors in FDD systems.

Process system tools, such as simulation and optimization of dynamic systems, are widely used in the process industries for development of operational strategies and control for process systems. These tools rely on thermodynamic models and many thermodynamic models have been developed for different compounds and mixtures. However, rigorous thermodynamic models are generally computationally intensive and not available as open-source libraries for process simulation and optimization. In this paper, we describe the application of a novel open-source rigorous thermodynamic library, ThermoLib, which is designed for dynamic simulation and optimization of vapor-liquid processes. ThermoLib is implemented in Matlab and C and uses cubic equations of state to compute vapor and liquid phase thermodynamic properties. The novelty of ThermoLib is that it provides analytical first and second order derivatives. These derivatives are needed for efficient dynamic simulation and optimization. The analytical derivatives improve the computational performance by a factor between 12 and 35 as compared to finite difference approximations. We present two examples that use ThermoLib routines in their implementations: (1) simulation of a vapor-compression cycle, and (2) optimal control of an isoenergetic-isochoric flash separation process. The ThermoLib software used in this paper is distributed as open-source software at www.psetools.org.

A battery powered air-conditioning device was developed to provide an improved thermal comfort level for individuals in inadequately cooled environments. This device is a battery powered air-conditioning system with the phase change material (PCM) for heat storage. The condenser heat is stored in the PCM during the cooling operation and is discharged while the battery is charged by using the vapor compression cycle as a thermosiphon loop. The main focus of the current research was on the development of the cooling system. The cooling capacity of the vapor compression cycle measured was 165.6 W with system COP at 2.85. It was able to provide 2 hours cooling without discharging heat to the ambient. The PCM was recharged in nearly 8 hours under thermosiphon mode.

A combined organic Rankine cycle and vapor compression cycle (ORC-VCC) system activated by low temperature heat sources was studied. Two low GWP fluids were considered as working fluids for the VCC and two different low GWP fluids for the ORC. System performance was evaluated through computational modeling over different operating conditions. The computed thermal COP of the ORC-VCC system varied between 0.30 and 1.10 over the range of operating conditions studied. The computed electrical COP of the ORC-VCC system, defined as the ratio of the rate of cooling and the ORC pump power consumption, varied between 15 and 110. The choice of VCC working fluid had only a limited influence on system thermal or electrical efficiency, with HFO-1234ze(E) presenting slightly better results. Use of HFO-1336mzz(Z) as the ORC working fluid resulted in slightly higher system thermal efficiencies and significantly higher system electrical efficiencies throughout the range of operating conditions studied. Furthermore, the system is evaluated for a typical application and the feasibility study shows good economical results.

A combined organic Rankine cycle and vapor compression cycle (ORC-VCC) system activated by low temperature heat sources was studied. Two low GWP fluids were considered as working fluids for the VCC and two different low GWP fluids for the ORC. System performance was evaluated through computational modeling over different operating conditions. The computed thermal COP of the ORC-VCC system varied between 0.30 and 1.10 over the range of operating conditions studied. The computed electrical COP of the ORC-VCC system, defined as the ratio of the rate of cooling and the ORC pump power consumption, varied between 15 and 110. The choice of VCC working fluid had only a limited influence on system thermal or electrical efficiency, with HFO-1234ze(E) presenting slightly better results. Use of HFO-1336mzz(Z) as the ORC working fluid resulted in slightly higher system thermal efficiencies and significantly higher system electrical efficiencies throughout the range of operating conditions studied. Furthermore, the system is evaluated for a typical application and the feasibility study shows good economical results.

An overview of the hybrid vapor compression ejector heat pump cycle developed under an American Recovery and Reinvestment Act funded contract is provided.

Within this project the possibility to build a very light and yet effective cooling machine has been investigated. The purpose is primarily to cool electronics in an Unmanned Aerial Vehicle (UAV). Electrically driven cooling machines have been in focus of the project to suit the More Electric Aircraft (MEA) concept. The normal method of cooling aircrafts today is by using a reversed Joule process, also called a reversed gas turbine process. The generally most used cooling machines, both ground-bound and mobile applications, are however all based on the vapor compression cycle, the typical electrical chiller cycle. The latter is more efficient, and thus when including the weight of the fuel needed to power the cooling cycle, it is very likely that the total weight of fuel and the cooling machine itself can be made lighter. Components that could lower the weight of vapor compression machines have been studied, such as new lightweight heat exchangers, motors and compressors. Especially small lightweight compressors would be a key component to further enhance the competitiveness of the Rankine chiller cycles., QC 20141104

Military mission performance in a chemically contaminated environment necessitates the wearing of chemically impermeable protective garments. Soldiers encapsulated in these protective garments in a hot environment will succumb to heat stress. Consequently a microclimate cooling system is being developed. In the present design, a vapor compression cycle chills water which is then circulated over the body to absorb heat via a cooling garment. One of the major components of the vapor compression cycle system is the prime mover, i.e. the engine. For battlefield use, the engine shall utilize battlefield fuel, JP-8. Commercially available engines of the required size, approximately 0.5 hp at 4000 rpm, such as model aircraft engines and small outdoor power equipment (string trimers) engines do not start and run on JP-8. This effort established the technical feasibility of starting and operating a small, lightweight engine on diesel fuel and JP-8. A commercially available 1.09 cubic inch displacement was used; however, the stock head was replaced with a custom designed head employing a fuel injector and pre-chamber. The engine started by hand cranking from ambient temperature (70 deg F) and ran without aids. 0.42 brake hp was developed at 3700 rpm. Brake specific fuel consumption was 0.76 lb/bbp-hr. microclimate cooling, diesel engines, individual soldier, protective clothing, diesel fuels , chemical contamination, heat stress(physiology), hot environment, chemical protection.

This study reviewed various combat vehicle crew compartment thermal conditioning concepts. A preliminary selection of candidate systems, based on performance, power, size, weight, logistics, cost, and development status elimated all concepts from further consideration except for air cycle and vapor cycle. Both the air and vapor cycle systems underwent a preliminary design evaluation and a detailed trade-off. Conclusions drawn from the preliminary design and trade-off of these two concepts are: (1) On a comparative point basis, the air and vapor cycles are equivalent; (2) The vapor cycle has distinct advantages in power and cost; (3) The air cycle has distinct advantages in performance and weight for outdoor conditions other than the main design condition of 120 F dry bulb temperature and 3% relative humidity; (4) The air cycle has a slight advantage in size and logistics; and (5) The trade-off categories of reliability and noise, safety, simplicity, maintainability and other are comparable for the two concepts.