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Comparison Of Two Object-Oriented Modeling Environments For The Dynamic Simulations Of A Residential Heat Pump, Viren Bhanot, Rohit Dhumane, Andrea Cioncolini, Paolo Petagna, Jiazhen Ling, Vikrant Chandramohan Aute, Reinhard Radermacher Jan 2018

Comparison Of Two Object-Oriented Modeling Environments For The Dynamic Simulations Of A Residential Heat Pump, Viren Bhanot, Rohit Dhumane, Andrea Cioncolini, Paolo Petagna, Jiazhen Ling, Vikrant Chandramohan Aute, Reinhard Radermacher

International Refrigeration and Air Conditioning Conference

Object-oriented physical-modelling platforms greatly facilitate the task of the modelling engineer by abstracting away a lot of the complexity associated with sorting the governing equations and also the nuances of the numerical methods used for solving the differential-algebraic equations (DAEs). For this reason, they have been steadily gaining in popularity in the field of thermofluid simulations. In this study, we compare two platforms of this type: Dymola and EcosimPro. Dymola is a physical modelling environment originally developed at Lund University and now being developed by Dassault Systèmes, and is a commercially available implementation of the open-source physical modelling language Modelica. …

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A Visualization Investigation On The Influence Of The Operating Conditions On The Phase Change In The Primary Convergent-Divergent Nozzle Of A Transcritical Co2 Ejector, Yafei Li, Jianqiang Deng, Li Ma, Yang He Jan 2018

A Visualization Investigation On The Influence Of The Operating Conditions On The Phase Change In The Primary Convergent-Divergent Nozzle Of A Transcritical Co2 Ejector, Yafei Li, Jianqiang Deng, Li Ma, Yang He

International Refrigeration and Air Conditioning Conference

Complex flow processes exist in the primary convergent-divergent nozzle of a transcritical CO2 ejector because of the rapid expansion of the supercritical CO2 flow, which have a significant influence on the performance of a transcritical CO2 ejector expansion refrigeration system. A visualization experiment with the direct photography method was carried out to investigate the phase change phenomena in the primary convergent-divergent nozzle of a transcritical CO2 ejector. The visualization transcritical CO2 ejector was designed as a rectangular cross section to minimize the optical distortion. In order to better interpret the phase change phenomena of CO2 flow, four pressure measurement points …

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Condensation And Evaporation Local Heat Transfer Characteristics Of The Refrigerant Mixture Of R1123 And R32 Inside A Plate Heat Exchanger, Keishi Kariya, Koki Sonoda, Syota Wakasugi, Yamato Eshima Jan 2018

Condensation And Evaporation Local Heat Transfer Characteristics Of The Refrigerant Mixture Of R1123 And R32 Inside A Plate Heat Exchanger, Keishi Kariya, Koki Sonoda, Syota Wakasugi, Yamato Eshima

International Refrigeration and Air Conditioning Conference

In the present study, condensation and evaporation local heat transfer coefficients of the refrigerant mixture of R1123 and R32 inside a brazed plate heat exchanger were investigated by using a test section which is combined with two grooved stainless steel plates. In the test section, wall temperature distribution was measured. The test section consists of eight plates; two of them were processed herringbone for refrigerant flow channel other two flat plates are set for cooling plate for refrigerant, and another consist on cooling water flow channel. In order to measure local heat transfer and temperature distribution, five thermocouples were set …

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A New Constant Air Volume Flow Regulation Method For Blowers Used In Hvac&R Systems, Bin Yang, Brian Beifus, Roger Becerra Jan 2018

A New Constant Air Volume Flow Regulation Method For Blowers Used In Hvac&R Systems, Bin Yang, Brian Beifus, Roger Becerra

International Refrigeration and Air Conditioning Conference

Accurate constant air volume flow rate regulation is essential in HVAC&R systems to provide comfort and required system performance. In the motor, the torque is regulated to provide the required air volume flow rate by monitoring the motor rotational speed. Various correlations including exponential functions and high order of polynomials used to regulate the torque in terms of motor speed and air volume flow rate are presented in the literature. However, all these formulas have not addressed the issue of inaccuracy of the air volume flow control in high altitudes regions. Therefore, a new 5-coefficient formula is proposed in this …

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Enhancement Of Ejection Systems Efficiency By Means Of Regenerative Heat Exchager, Kamil Smierciew, Jerzy Gagan, Dariusz Butrymowicz, Michal ?Ukaszuk Jan 2018

Enhancement Of Ejection Systems Efficiency By Means Of Regenerative Heat Exchager, Kamil Smierciew, Jerzy Gagan, Dariusz Butrymowicz, Michal ?Ukaszuk

International Refrigeration and Air Conditioning Conference

Recently the ejection system became more nad more interesting for investigators. The reason for this is, on the one hand, the necessity to apply new low-GWP working fluids, and on the other hand, the necessity to save electric energy required by classic compression refrigeration systems. Ejection system can utilize free renewable or low-grade waste heast as a motive source. Despite all advantages of the ejection systems, such as simple construction, no moving parts, no maintenance operation one of the main disadvantage of these systems is their low efficiency described by coefficient of performance (COP). Improvement of the COP of the …

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Model-Free Control And Automatic Staging Of Variable Refrigerant Flow System With Multiple Outdoor Units, Liujia Dong, Yaoyu Li, Tim Salsbury, John M. House Jan 2018

Model-Free Control And Automatic Staging Of Variable Refrigerant Flow System With Multiple Outdoor Units, Liujia Dong, Yaoyu Li, Tim Salsbury, John M. House

International Refrigeration and Air Conditioning Conference

For efficient operation of a variable refrigerant flow (VRF) air conditioning system with multiple outdoor units (ODUs), we propose a model-free control strategy based on extremum seeking control along with automatic staging control logic. The proposed strategy is evaluated with a representative VRF system consisting of 12 indoor units (IDUs) and three ODUs. The IDU zone temperature is regulated by EEV opening, and the compressor pressure is regulated by compressor speed. To optimize load sharing among multiple ODUs in operation, a set of bypass valves (BPVs) are added to the suction side of the compressors to manipulate refrigerant flow distribution …

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Charge Equation For Small Charge Hydrocarbon Based Commercial Refrigeration Appliances, Marcel Van Beek, Thijs Van Gorp Jan 2018

Charge Equation For Small Charge Hydrocarbon Based Commercial Refrigeration Appliances, Marcel Van Beek, Thijs Van Gorp

International Refrigeration and Air Conditioning Conference

The use of hydrocarbon refrigerants has become common practice for small commercial appliances. The charge of hydrocarbon is limited by safety regulations. Therefore, refrigerant charge has become a critical design parameter for these appliances. To assist manufacturers in their early stage of appliance design (i.e. component selection) an easy to implement charge equation has been developed. The equation estimates the total appliance refrigerant charge based on the refrigerant, the operating conditions and the internal volume of the components of the cooling system. This paper presents the charge equation developed and discusses the derivation, assumptions and underlying calculations in detail. It …

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Heat Transfer Process Within The R744 Two-Phase Ejector: Numerical And Experimental Study, Michal Haida, Jacek Smolka, Armin Hafner, Mikolaj Mastrowski, Michal Palacz, Kenneth B. Madsen, Andrzej J. Nowak, Krzysztof Banasiak Jan 2018

Heat Transfer Process Within The R744 Two-Phase Ejector: Numerical And Experimental Study, Michal Haida, Jacek Smolka, Armin Hafner, Mikolaj Mastrowski, Michal Palacz, Kenneth B. Madsen, Andrzej J. Nowak, Krzysztof Banasiak

International Refrigeration and Air Conditioning Conference

The proposed three dimensional CFD model to simulate the influence of the heat transfer on the R744 two-phase ejector performance is presented. The numerical model was developed based on the homogeneous real fluid flow assumption with the enthalpy-based formulation of the energy equation. The R744 two-phase ejector was designed to evaluate the temperature profile within the ejector walls. The prototype R744 ejector for experimental investigation was manufactured by Institute of Thermal Technology and ATM in Poland. The performance measurements were carried out at a R744 test facility at SINTEF/NTNU in Norway. The foregoing ejector was equipped with the thirteen thermocouples …

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Weld Shape Optimization For Pillow Plate Heat Exchangers, Radia Eldeeb, Jiazhen Ling, Vikrant Chandramohan Aute, Reinhard Radermacher Jan 2018

Weld Shape Optimization For Pillow Plate Heat Exchangers, Radia Eldeeb, Jiazhen Ling, Vikrant Chandramohan Aute, Reinhard Radermacher

International Refrigeration and Air Conditioning Conference

Miniaturization of Plate Heat Exchangers (PHXs) is becoming a central research topic in order to utilize less material and less refrigerant charge to attain similar heat transfer performance, and hence contribute significantly into energy conservation and lower environmental impact. Thus, it is greatly desirable to obtain new designs to achieve this goal. Pillow Plate Heat Exchanger (PPHX) is a type of PHXs with a 3D complex wavy structure, but yet an economical manufacturing process positioning itself as a potential strong competitor among other types of PHXs. PPHXs have the advantage of simple manufacturing process which gives it great design flexibility, …

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Comparison And Optimization Of Three Types Of Refrigeration System Under Different Operating Conditions, Shumin Lin, Xingbiao Zhou Jan 2018

Comparison And Optimization Of Three Types Of Refrigeration System Under Different Operating Conditions, Shumin Lin, Xingbiao Zhou

International Refrigeration and Air Conditioning Conference

As well known, the performance of the compressor is concerned with the corresponding refrigeration system. In this paper, by comparing three types of refrigeration cycle, an optimized range of the intermediate pressure for gaining better coefficient of performance (COP) is proposed. Additionally, the effect of the cycle on the construction of the compressor and performances under different refrigerants are discussed. The simulation result indicates that the coefficient of intermediate pressure under freezing condition and refrigeration condition ranges from 0.81 to 0.91 and 0.93 to 0.97, respectively. The results obtained here may provide some guides for the optimal design and operation …

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Numerical Analysis Of Fluid Flow And Heat Transfer In Wavy And Hybrid-Slit-Wavy (Hsw) Fin-And-Tube Heat Exchangers, Lokanath Mohanta, Arindom Joardar, Jack Esformes, Brian Videto, Tobias Sienel Jan 2018

Numerical Analysis Of Fluid Flow And Heat Transfer In Wavy And Hybrid-Slit-Wavy (Hsw) Fin-And-Tube Heat Exchangers, Lokanath Mohanta, Arindom Joardar, Jack Esformes, Brian Videto, Tobias Sienel

International Refrigeration and Air Conditioning Conference

This numerical study pertains to characterizing flow and heat transfer interactions for an interrupted fin design with wavy profile in compact tube-and-fin heat exchanger. Although designs with similar concept is prevalent in the HVAC&R industry not much literature exists on the subject combining wavy fins with periodic interruptions. Presently sinusoidal wavy fin is combined with slit fins to investigate thermal-hydraulic performance relative to an un-interrupted fin design. This fin is referred to as Hybrid Slit Wavy (HSW) fin in this work. Commercial Computational Fluid Dynamics (CFD) software is used for 3D numerical solution of the complete Navier–Stokes and energy equations …

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Simulation And Performance Correlation For Transcritical Co2 Heat Pump Cycle, Ahmed Okasha, Norbert Müller Jan 2018

Simulation And Performance Correlation For Transcritical Co2 Heat Pump Cycle, Ahmed Okasha, Norbert Müller

International Refrigeration and Air Conditioning Conference

For more than a decade, carbon dioxide (R744) has been revived as a natural environmentally friendly refrigerant. Compared to HFC refrigerants with a global warming potential (GWP) in the order of 1300-1900, R744 has a GWP of 1. As it is relevant for R744 heat pumps, a transcritical cycle has an extra degree of freedom with the gas cooler pressure and outlet temperature being thermodynamically independent of each other. Utilizing MATLAB integrated with the NIST REFPROP thermodynamic database, a single stage transcritical R744 heat pump cycle is modeled and simulated. The isentropic and volumetric efficiency correlations of a commercial semi-hermetic …

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Artificial Neural Networks For Fast Rooftop Unit Fault Impact Modeling And Simulation, Andrew L. Hjortland, James E. Braun Jan 2018

Artificial Neural Networks For Fast Rooftop Unit Fault Impact Modeling And Simulation, Andrew L. Hjortland, James E. Braun

International Refrigeration and Air Conditioning Conference

Like any electromechanical system, direct-expansion (DX) air conditioners and heat pumps often develop faults over time that contribute to reduced operating efficiency, more frequent comfort violations, or even premature failure. Automated fault detection and diagnosis (AFDD) methods have been developed for these systems and much experimental effort has been undertaken for their evaluation. In order to reduce development costs required for AFDD technologies, additional research related to modeling DX equipment subject to faults has been undertaken. Investigation of AFDD methods in a virtual environment typically requires relatively detailed equipment models based in some part on thermodynamic principles. Because of these …

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An Empirical Model For Refrigerant Flammability Based On Molecular Structure And Thermodynamics, Greg Linteris, Ian Bell, M. O. Mclinden Jan 2018

An Empirical Model For Refrigerant Flammability Based On Molecular Structure And Thermodynamics, Greg Linteris, Ian Bell, M. O. Mclinden

International Refrigeration and Air Conditioning Conference

Screening methods for refrigerant blend flammability using metrics that can be easily calculated are of great interest to the refrigerant industry. Existing flammability metrics such as heat of combustion are not adequate for hydrofluorocarbon blends. Alternative metrics are needed that can be used to assess the flammability of refrigerant blends without requiring time-consuming experimental measurements. In this work we study the combination of the maximum adiabatic flame temperature and the fluorine-substitution ratio as metrics for characterizing the flammability of refrigerant blends. The combination of these metrics yields an estimate of the flammability class of refrigerants (both blends and pure fluids) …

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A Simulation Study On Two-Phase Microchannel Evaporator Header Distribution Using Computational Fluid Dynamics Header Model And Segmented Heat Transfer Tube Model, Long Huang, Motohiko Fukuoka, Toshimitsu Kamada, Noriyuki Okuda Jan 2018

A Simulation Study On Two-Phase Microchannel Evaporator Header Distribution Using Computational Fluid Dynamics Header Model And Segmented Heat Transfer Tube Model, Long Huang, Motohiko Fukuoka, Toshimitsu Kamada, Noriyuki Okuda

International Refrigeration and Air Conditioning Conference

One of the major challenges in Microchannel Heat Exchanger (MCHX) design is the flow mal-distribution from the header into different flow passes, especially for evaporator applications with two-phase refrigerant. Computational Fluid Dynamics (CFD) simulation is extensively used in the heat exchanger design processes and performance evaluations. The Eulerian Multiple Flow Regimes model in STAR-CCM+® modeling environment combines the benefits of the commonly used Volume of Fluid model and Eulerian Multiphase model. This newly available model allows simulation to capture free surfaces, dispersed sprays and dispersed bubbles. R-32 is selected in this study as it is widely used in split type …

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Wom: Whole Orc Model, Saverio Randi, Nicola Casari, Michele Pinelli, Alessio Suman, Davide Ziviani Jan 2018

Wom: Whole Orc Model, Saverio Randi, Nicola Casari, Michele Pinelli, Alessio Suman, Davide Ziviani

International Refrigeration and Air Conditioning Conference

Over the last decade, environmental and economic concerns have pushed the researchers to find new solutions in the track of a more responsible use of energy. Particularly, small scale organic Rankine cycles (ORCs) have been regarded as candidate for a better employment of waste energy. In order to increase the performance of these cycles and to extend their operating range, attention has been drawn on the behavior of the different components both experimentally as well as by means of computational fluid dynamics (CFD) simulations. The numerical approach has been increasingly used in the study of the machines that compose the …

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Three-Fluid Heat Exchanger As Evaporator In Multi-Source Heat Pumps With Viable Options For Alternative Defrosting Methods, Thore Oltersdorf, Gerhard Schmitz, Hans-Martin Henning Jan 2018

Three-Fluid Heat Exchanger As Evaporator In Multi-Source Heat Pumps With Viable Options For Alternative Defrosting Methods, Thore Oltersdorf, Gerhard Schmitz, Hans-Martin Henning

International Refrigeration and Air Conditioning Conference

Three-fluid evaporators can be used for multi-source heat pumps to keep refrigeration circuits simple in design since it avoids the usage of a second or more evaporators. In this work a defrosting control design is presented with a lowered electrical energy demand compared to the standard procedure of reverse flow defrosting with 4-way-valves. Objective of this new defrosting concept is to develop a fully autonomous defrosting strategy. The two heat sources allow direct thermal communication of an air source and a second heat source based on a hydronic circuit with the evaporating refrigerant. The proposed defrosting strategy is based on …

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Disproportionation Reaction Of Hfo-1123 Refrigerant, Makoto Ito, Naoya Kurokawa, Chaobin Dang, Eiji Hihara Jan 2018

Disproportionation Reaction Of Hfo-1123 Refrigerant, Makoto Ito, Naoya Kurokawa, Chaobin Dang, Eiji Hihara

International Refrigeration and Air Conditioning Conference

In the field of refrigeration and air conditioning, the transition from using chlorofluorocarbon (CFC) and hydrochlorofluorocarbon (HCFC) refrigerants to using hydrofluorocarbon (HFC) refrigerants is in progress, driven by the need to prevent the depletion of the stratospheric ozone layer. Although HFC refrigerants are useful from the viewpoint of ozone layer protection, their high global warming potential (GWP) is a serious concern. Following the passing of the Kigali Amendment to the Montreal Protocol, UN member nations are now required to switch to low-GWP refrigerants, such as hydrofluoro-olefins (HFO), and natural refrigerants. HFO-1123 is a substance with a very low GWP and …

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Performance Evaluation Of Heat Pump Systems Based On A Load-Based Testing Methodology, Parveen Dhillon, Akash Patil, Li Cheng, James E. Braun, W. Travis Horton Jan 2018

Performance Evaluation Of Heat Pump Systems Based On A Load-Based Testing Methodology, Parveen Dhillon, Akash Patil, Li Cheng, James E. Braun, W. Travis Horton

International Refrigeration and Air Conditioning Conference

This paper presents results of testing variable-speed heat pumps using a new load-based testing methodology that is described in a companion paper. The testing methodology involves emulating the response of a building’s sensible and latent loads to equipment controls by dynamically adjusting the temperature and humidity setpoints of the psychrometric chamber reconditioning system using a simple building model. The advantage of this approach over existing testing approaches specified in ratings standards is that it considers the interaction of the integrated controls with the equipment. As a result, it better captures the full range of part-load operation and the benefits of …

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A Preliminary Experimental Study On The Performance Of A Membrane-Based Air Dehumidifier Using Ionic Liquid, Xiaobing Liu, Joseph Warner, Ming Qu, Xiaoli Liu, Harish Opadrishta, Parmalee William Jan 2018

A Preliminary Experimental Study On The Performance Of A Membrane-Based Air Dehumidifier Using Ionic Liquid, Xiaobing Liu, Joseph Warner, Ming Qu, Xiaoli Liu, Harish Opadrishta, Parmalee William

International Refrigeration and Air Conditioning Conference

Liquid desiccant air dehumidification (LDAD) is a promising alternative to the dehumidification systems that use mechanical cooling. However, its use in the market is still very limited due to its high installation cost, intensive carryover, and maintenance issues associated with the corrosion resulting from conventional liquid desiccants. The research reported in this paper aimed at addressing these challenges by applying membrane technology and ionic liquids in LDAD. This paper introduces a design of a membrane-based ionic liquid desiccant air dehumidification (MILDAD). A small-scale prototype of the MILDAD was built and tested in controlled conditions to characterize its performance. The preliminary …

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Compatibility Of Filler And Base Metals In Heat Exchanger Manufacturing Process, Hui Zhao, Stefan Elbel, Predrag S. Hrnjak Jan 2018

Compatibility Of Filler And Base Metals In Heat Exchanger Manufacturing Process, Hui Zhao, Stefan Elbel, Predrag S. Hrnjak

International Refrigeration and Air Conditioning Conference

Aluminum is one of the most commonly used metals for manufacturing heat exchanger. Mass production of compact aluminum heat exchangers can be achieved by furnace or flame brazing with the assistance of fluxes. It is well known that a brazing process relies on the capillary flow of liquid filler metal on the base surfaces of various heat exchanger components. Proper selection of heater exchanger materials is essential for the success of a brazing process. For example, the 6xxx series aluminum alloys are a popular selection in production processes due to their excellent mechanical strength and good machinability. However, the high …

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Uncertainty Analysis Of The Experimental Results Of Air Conditioner Performance Due To The Uncertainty Of The Equation Of State, Howard Cheung, Jérôme Frutiger, Ian Bell, Jens Abildskov, Gürkan Sin, Shengwei Wang Jan 2018

Uncertainty Analysis Of The Experimental Results Of Air Conditioner Performance Due To The Uncertainty Of The Equation Of State, Howard Cheung, Jérôme Frutiger, Ian Bell, Jens Abildskov, Gürkan Sin, Shengwei Wang

International Refrigeration and Air Conditioning Conference

In previous literature, the uncertainty analyses of experimental results of air conditioners usually ignored the uncertainty due to the equation of state (EoS) of the refrigerants. One possible reason was that the uncertainty reported in the EoS literature was much smaller than the one of the measurement. However, with the advancement of measurement technologies, the impact of measurement uncertainty on the air conditioner performance calculation is lowered and becomes on par with that of the EoS. Simultaneously, new research findings give more comprehensive understanding of the EoS uncertainties, such as that the uncertainty of EoS reported in previous studies was …

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Comparing Realtime Energy-Optimizing Controllers For Heat Pumps, Daniel Burns, Scott A. Bortoff, Martin Guay, Christopher Laughman Jan 2018

Comparing Realtime Energy-Optimizing Controllers For Heat Pumps, Daniel Burns, Scott A. Bortoff, Martin Guay, Christopher Laughman

International Refrigeration and Air Conditioning Conference

As the vapor compression machine has become more sophisticated (for example, through the adoption of variable speed compressor technology, electronic expansion valves and variable speed fans), the opportunities to improve efficiency are increasingly realized through the control algorithms that operate machine actuators. However, designing control algorithms that minimize energy consumption is not straightforward: the heat load disturbances to be rejected are not measured, the governing dynamics are nonlinear and interactive, and the machine exhibits strong coupling between the multivariate inputs and outputs. Further, many heat pumps must also operate in cooling mode, forcing compromises in sensor locations and actuator selection. …

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Numerical Investigation Of A Forced-Air Cooled Condenser Using 1d-3d-Coupling, Bernhard Zuber, Johann Hopfgartner, Andreas Egger, Raimund Almbauer Jan 2018

Numerical Investigation Of A Forced-Air Cooled Condenser Using 1d-3d-Coupling, Bernhard Zuber, Johann Hopfgartner, Andreas Egger, Raimund Almbauer

International Refrigeration and Air Conditioning Conference

To further improve the efficiency of refrigerators and freezers, it is necessary to optimize the whole cooling cycle. With one-dimensional numerical simulation programs, the transient behavior of the refrigeration cycle over more than 24 hours can be calculated. A major challenge here is to find appropriate heat transfer coefficients especially when the heat transfer is mainly influenced by forced-ventilation. In the present paper a refrigerator with a forced-air cooled condenser is investigated. To take the influences of the air flow and the condenser geometry on the simulated heat transfer into consideration, three-dimensional flow simulations are used. Due to superheating, subcooling …

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Monitoring Of A Commercial Refrigeration Co2 System And Comparison With Simulations, Marco Azzolin, Livio Calabrese, Simone Dugaria, Silvia Minetto, Davide Del Col Jan 2018

Monitoring Of A Commercial Refrigeration Co2 System And Comparison With Simulations, Marco Azzolin, Livio Calabrese, Simone Dugaria, Silvia Minetto, Davide Del Col

International Refrigeration and Air Conditioning Conference

The demand for natural refrigerants is growing in commercial refrigeration systems. In the recent years, carbon dioxide has increased its market share in the field of commercial refrigeration and has proven to be a viable solution for the replacement of hydrofluorocarbon (HFC) systems. This success is mainly due to the ongoing technological evolution of carbon dioxide refrigeration systems. In the present paper, a CO2 commercial refrigeration unit serving a supermarket located in Northern Italy is presented. The unit consists of a booster compressor rack with parallel compression, with ten compressors arranged to provide around 20 kW cooling capacity at low …

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Performance And Stability Of E-1233zd In Energy Recovery Applications, Sarah Kim, Wissam Rached, Laurent Abbas Jan 2018

Performance And Stability Of E-1233zd In Energy Recovery Applications, Sarah Kim, Wissam Rached, Laurent Abbas

International Refrigeration and Air Conditioning Conference

Developed and identified as a refrigerant for low pressure chillers, Trans-1-chloro-3,3,3-trifluoropropene (E-1233zd) an unsaturated molecule, with a GWP of 1, has also shown a high potential as a working fluid for energy recovery applications, such as organic Rankine cycle or high temperature heat pumps. As a refrigerant for low pressure chillers, E-1233zd has shown positive attributes of high performance and low environmental impact, while maintaining the safety benefits of refrigerants commonly used today, by being non-flammable and having a low toxicity. However, when significant heat is applied, the E-1233zd was found to undergo geometric isomerization, which could limit its performance …

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Conceptual Design Of A Manufacturing Process For An Automotive Microchannel Heat Exchanger, Brian Paul, Chuankai Song, Kijoon Lee, Brian M. Fronk, Dipankar Sahoo, Michael Shipley Jan 2018

Conceptual Design Of A Manufacturing Process For An Automotive Microchannel Heat Exchanger, Brian Paul, Chuankai Song, Kijoon Lee, Brian M. Fronk, Dipankar Sahoo, Michael Shipley

International Refrigeration and Air Conditioning Conference

Calls for higher fuel efficiency in the United States and Europe are driving the need for waste heat recovery in automotive markets. While conventional heat exchangers can be designed to meet the heat duty requirement, the resulting volume, weight, and thermal mass are too large for rapid transient response and packaging of the device. The lightweight, compact form factor of microchannel heat exchangers with submillimeter flow passages is attractive for automotive applications. However, the industrial use of microchannel heat exchangers continues to be inhibited by high manufacturing costs. The objective of this paper is to develop a microchannel heat exchanger …

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Analysis Of Tes With Pcm (Solid/Liquid) Integrated In A Residential System, Zidu Ma Jan 2018

Analysis Of Tes With Pcm (Solid/Liquid) Integrated In A Residential System, Zidu Ma

International Refrigeration and Air Conditioning Conference

Thermal Energy Storage (TES) with Phase Change Materials (PCM) media (solid/liquid) has been investigated as an add on component to small residential systems. Simple conceptual design on the integration of TES as add-on component to typical systems has been investigated. A basic analyis with simple cycles is to be presented to answer the question whether TES integrated with existing VCC cycles could offer energy savings. In addition, the analysis is used to study the effect of subcool and/or temperature hyserisis by using the ideal Carnot Cycle. Organic PCM materials have low thermal conducitivity (0.15w/m-C to 0.20w/m-C) compared with inorganic PCMs …

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Theoretical Model For Buoyancy-Induced Heat Transfer Deterioration Under Supercritical Pressure, Jiacheng He, Chaobin Dang, Eiji Hihara Jan 2018

Theoretical Model For Buoyancy-Induced Heat Transfer Deterioration Under Supercritical Pressure, Jiacheng He, Chaobin Dang, Eiji Hihara

International Refrigeration and Air Conditioning Conference

In an organic Rankine cycle system which utilizes the low-grade heat sources in various industrial processes, operating the heating process at supercritical pressure provides a possibility to increase the system efficiency because more work can be recovered. Under this background, it is necessary to investigate the supercritical heat transfer characteristics of the organic working fluids. In this study, the characteristics of supercritical heat transfer of fluid R245fa, which is commonly applied in the commercial ORC power plant, and R1233zd(E), which is recognized as an alternative working fluid owing to its low-global-warming-potential value, were investigated experimentally under the heating condition in …

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Theoretical Study On A Modified Subcooling Vapor-Compression Refrigeration Cycle Using Hydrocarbon Mixture R290/R600a, Qi Chen, Jianlin Yu, Gang Yan, Yunho Hwang Jan 2018

Theoretical Study On A Modified Subcooling Vapor-Compression Refrigeration Cycle Using Hydrocarbon Mixture R290/R600a, Qi Chen, Jianlin Yu, Gang Yan, Yunho Hwang

International Refrigeration and Air Conditioning Conference

In this study, a modified subcooling vapor-compression refrigeration cycle (MSVRC) using refrigerant mixture R290/R600a was proposed for applications in refrigerator-freezers. In the MSVRC, A phase separator is utilized to split the refrigerant mixture and obtain two different components after partial condensation in the condenser. Moreover, an internal evaporating subcooler is introduced to enhance the overall system performance. Energetic and exergetic analysis methods are used to theoretically evaluate the system operating performance of MSVRC and compared with the traditional vapor-compression refrigeration cycle (TVRC). The simulation results show that the MSVRC outperforms TVRC in the aspect of coefficient of performance (COP), volumetric …

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