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Full-Text Articles in Entire DC Network
Modeling Of The Nist Intelligent Building Agents Labratory, Adam Jacob Kopach
Modeling Of The Nist Intelligent Building Agents Labratory, Adam Jacob Kopach
International High Performance Buildings Conference
The Intelligent Building Agents Laboratory (IBAL) at the National Institute of Standards and Technology (NIST) will be used to experimentally study control strategies within the realm of commercial building air-conditioning systems. A simulation software (Klein, 2020) model of the IBAL has been created to help guide the experiments in the IBAL and to provide a software-based method of evaluating control strategies implemented in this facility. This simulation model is composed of the various components comprising the IBAL HVAC system such as heating coils, cooling coils, fans and dampers that can accurately simulate the actual component behavior under transient and off-design …
Numerical Analysis On A Perforated Muffler Applied In The Discharge Chamber Of A Twin Screw Refrigeration Compressor Based On Fluid-Acoustic Coupling Method, Shizhong Sun, Ziwen Xing, Wenqing Chen, Minglong Zhou, Yu Hua Huang, Po Chia Su
Numerical Analysis On A Perforated Muffler Applied In The Discharge Chamber Of A Twin Screw Refrigeration Compressor Based On Fluid-Acoustic Coupling Method, Shizhong Sun, Ziwen Xing, Wenqing Chen, Minglong Zhou, Yu Hua Huang, Po Chia Su
International Compressor Engineering Conference
The twin screw compressor has been widely used in the refrigeration systems due to advantages such as compact structure, stable operation, high efficiency and good adaptability. Intermittent gas flow generates gas pulsation that cause serious problems such as structural vibration and noise in the twin screw refrigeration compressor. Because the mechanical noise can be controlled well with the improvement of machining and assembly accuracy, the aerodynamic noise induced by gas pulsation even has become the main noise source of the twin screw refrigeration compressor. In order to reduce the pressure pulsation, a broadband perforated panel muffler applied in the discharge …
Exergetic Optimisation Of Vortex Tubes Using A Thermodynamic Model, Junior Lagrandeur, Sergio Croquer, Sébastien Poncet, Mikhail Sorin
Exergetic Optimisation Of Vortex Tubes Using A Thermodynamic Model, Junior Lagrandeur, Sergio Croquer, Sébastien Poncet, Mikhail Sorin
International Refrigeration and Air Conditioning Conference
This article identifies sources of exergy losses in a vortex tube working with air by using a recently developed thermodynamic model and a reference experiment from the literature. Exergetic efficiency considering transiting exergy is used as the efficiency metrics in this work. When both the cold and hot outlets are useful, the exergetic efficiency reaches its maximum value for a cold mass fraction equal to 0.7. Interestingly, up to 45% of the inlet exergy is lost downstream of the vortex tube under this condition because of pressure losses in the cold tube and through measuring instruments. These losses do not …
A Nonlinear Model Order Reduction Framework For Dynamic Vapor Compression Cycles Via Proper Orthogonal Decomposition, Jiacheng Ma, Donghun Kim, James E. Braun
A Nonlinear Model Order Reduction Framework For Dynamic Vapor Compression Cycles Via Proper Orthogonal Decomposition, Jiacheng Ma, Donghun Kim, James E. Braun
International Refrigeration and Air Conditioning Conference
A computationally efficient and accurate modeling approach is critically important for designing and evaluating controls and fault detection and diagnosis (FDD) algorithms. This paper proposes a reduced order modeling approach for vapor compression cycles (VCC) that involves application of nonlinear model order reduction (MOR) methods to dynamic heat exchanger (HX) models to generate reduced order HX models. A reformulated finite volume HX model was first developed that matches the baseline MOR model structure. Then, a nonlinear MOR framework based on Proper Orthogonal Decomposition (POD) and a Discrete Empirical Interpolation Method (DEIM) was developed for generating nonlinear reduced order HX models. …
Test Of Condensing Units’ Performance And Operating Limits Using Different Low Gwp Refrigerants, Etienne Haddad, Assaad Zoughaib, Samer Saab
Test Of Condensing Units’ Performance And Operating Limits Using Different Low Gwp Refrigerants, Etienne Haddad, Assaad Zoughaib, Samer Saab
International Refrigeration and Air Conditioning Conference
The European regulation has set a series of limitation to reach the objective of reducing the Global Warming Potential (GWP) emissions. Among these limits, the ban of Hydrofluorocarbons (HFC) refrigerants having a GWP higher than 2500 starting 2020. To replace these refrigerants, a new family of refrigerants was invented: hydro-fluoro-olefins (HFOs), also new systems were developed using CO2. In this paper, we present the outcome of a testing campaign aiming to compare the performance, operating range and cost of two condensing units of a rated capacity of 8kW cooling a secondary glycol loop. One of these machines, initially operated with …
Two-Phase Refrigerant Flow In The Inlet Header Of Brazed Plate Heat Exchangers: Visualization And Its Effect On Distribution, Wenzhe Li, Pega Hrnjak
Two-Phase Refrigerant Flow In The Inlet Header Of Brazed Plate Heat Exchangers: Visualization And Its Effect On Distribution, Wenzhe Li, Pega Hrnjak
International Refrigeration and Air Conditioning Conference
When used as direct expansion (DX) evaporators, brazed plate heat exchangers (BPHEs) suffer from the maldistribution of the two-phase refrigerant flow among parallel plate channels. One of the critical mechanisms of two-phase maldistribution is the phase separation in the inlet header. This paper presents an experimental investigation of the two-phase refrigerant (R134a) flow in the inlet header of a brazed plate evaporator and its effects on the distribution. Visualization of two-phase flow is accomplished through a 3D-printed transparent window at the inlet header of the heat exchanger. The observed flow regime is periodic and three stages are identified in a …
Experimental Study On Boiling And Condensation Heat Transfer Of R1234yf Inside A Plate Heat Exchanger, Saide Diaw, Thiha Tun, Kunpei Yoshida, Keishi Kariya, Akio Miyara
Experimental Study On Boiling And Condensation Heat Transfer Of R1234yf Inside A Plate Heat Exchanger, Saide Diaw, Thiha Tun, Kunpei Yoshida, Keishi Kariya, Akio Miyara
International Refrigeration and Air Conditioning Conference
In this study, boiling and condensation heat transfer characteristics of refrigerant R1234yf flowing inside a channel of plate heat exchanger were experimentally investigated. The test section consists of 8 plates where the refrigerant flow channel is formed by two plates grooved chevron pattern. Other plates are used to measure local temperature distribution and to form cooling /heating water channel. In this experiment three vertical flow channel exist in the test section and where the refrigerant flows in the middle channel (upward or downward directions) depending on evaporation or condensation process. In case of evaporation process the refrigerant flows upward in …
Development Of Dynamic Modeling Framework Using Convolution Neuron Network For Variable Refrigerant Flow Systems, Hanlong Wan, Tao Cao, Yunho Hwang, Saikee Oh
Development Of Dynamic Modeling Framework Using Convolution Neuron Network For Variable Refrigerant Flow Systems, Hanlong Wan, Tao Cao, Yunho Hwang, Saikee Oh
International Refrigeration and Air Conditioning Conference
Modeling the air conditioning system provides an excellent tool for system design, control, operation, and fault diagnosis. Such models were developed as either steady-state and transient models or knowledge-based and physics-based models. Most of the current studies mainly concentrated on physics-based models or steady-state models. Knowledge-based dynamic models were rarely discussed. In this paper, a knowledge-based dynamic model using a Convolutional Neural Network was developed for the air conditioning system. Instead of using operating parameters at a time point, we used the numbers in a time window as input data. We conducted a case study of the variable refrigerant flow …
Experimental Test Rig For The Visualisation Study Of The Transcritical Flow In The Two-Phase R744 Ejectors, Jakub Bodys, Michał Palacz, Michał Haida, Jacek Smolka, Andrzej J. Nowak
Experimental Test Rig For The Visualisation Study Of The Transcritical Flow In The Two-Phase R744 Ejectors, Jakub Bodys, Michał Palacz, Michał Haida, Jacek Smolka, Andrzej J. Nowak
International Refrigeration and Air Conditioning Conference
Recent studies have provided the significant number of approaches to enhance the performance of a twophase ejector, especially for transcritical CO2 cycles. However, the investigation of the mixing process is still challenging matter due to the highspeed fluid flow coupled with mixing of vapour and partially evaporated liquid stream. On the other hand, these phenomena directly influence the ejector efficiency. The behaviour of the aforementioned processes would be valuable for validation the numerical models as well as a required control of the system operation. Hence, in this work, the laboratory test rig for visualisation of the CO2 ejector mixing processes …
Design Of Net Zero Energy Environmental Engineering Building In Peru, William Hutzel, Pedro Flores-Larico, Travis Horton, Mark Zimpfer
Design Of Net Zero Energy Environmental Engineering Building In Peru, William Hutzel, Pedro Flores-Larico, Travis Horton, Mark Zimpfer
International High Performance Buildings Conference
This paper describes a Net Zero Energy Building (NZEB) being constructed on the engineering campus of the Universidad Nacional de San Augustín (UNSA) in Arequipa, Peru. The project is one part of a larger collaboration between UNSA and Purdue University called the Arequipa Nexus Institute for Sustainable Food, Energy, Water and the Environment (The Nexus Institute) that started in March of 2018. As UNSA seeks to become a leader in environmental engineering, there is an increasing need for a new building that has dedicated resources for teaching and research on sustainable design. Solar panels to achieve net zero energy were …
A Data-Driven Model Development For Generalized Building Energy Predictions, Tao Cao, Lei Gao, Vikrant C. Aute, Yunho Hwang
A Data-Driven Model Development For Generalized Building Energy Predictions, Tao Cao, Lei Gao, Vikrant C. Aute, Yunho Hwang
International High Performance Buildings Conference
Building energy predictions are in critical need in many fields. The conventional physic model-based approach (via EnergyPlus or similar tools) does decent work to predict energy consumptions. However, it is limited to single predefined building analysis and requires an extensive amount of time and labor to build models. Nevertheless, decision-makers usually need to quantify the energy savings of large building clusters within a short time. The thriving of big data and machine learning techniques enables predicting energy consumptions accurately for different applications within reasonable time frames. This study aims at developing data-driven models for generalized building energy predictions. The models …
Development Of Climate Classification Through Hierarchical Clustering For Building Energy Simulation, Giovanni Pernigotto, Andrea Gasparella, Jan Hensen
Development Of Climate Classification Through Hierarchical Clustering For Building Energy Simulation, Giovanni Pernigotto, Andrea Gasparella, Jan Hensen
International High Performance Buildings Conference
Climate classification plays an important role for the identification of homogeneous groups of climates, from which representative locations can be extracted and used for building energy simulation analyses. Nevertheless, according to the current state-of-the-art, the main reference systems consider just a fraction of those weather quantities which are relevant in the building energy balance, i.e., ambient temperature and humidity and solar radiation. To overcome this issue, in previous researches a new methodology was defined, based on monthly series of weather quantities, statistical analyses and data-mining techniques for climate clustering. In this work, with the aim of further developing such approach, …
Superheat Prediction & Fault Diagnostics Of Hvac From Simple Temperature Measurements Using Big Data Approach, Mehari Tesfay, Fadi Alsaleem, Kevin Sinkar, Parthiban Arunasalam
Superheat Prediction & Fault Diagnostics Of Hvac From Simple Temperature Measurements Using Big Data Approach, Mehari Tesfay, Fadi Alsaleem, Kevin Sinkar, Parthiban Arunasalam
International High Performance Buildings Conference
No abstract provided.
A Modeling Approach To Characterize The Demand Flexibility Of The Air Distribution System In Commercial Buildings, Elvin Vindel, Mario Berges, Burcu Akinci
A Modeling Approach To Characterize The Demand Flexibility Of The Air Distribution System In Commercial Buildings, Elvin Vindel, Mario Berges, Burcu Akinci
International High Performance Buildings Conference
Commercial VAV systems have been a studied as potential flexible power consumption resources to provide these services. A significant limitation is the development of control oriented models for these systems that accurately control power consumption across timescales. To this end, we develop a modeling approach that characterizes the demand flexibility of the air distribution system in commercial buildings. The model maps all feasible terminal zone damper configurations to power consumption by identifying a system resistance model connected to a pressure-flow model of the supply fan. Under this model structure, the operational range of an installed system can be quantitatively bounded …
Assessing The Value Of Uncertainty-Aware Transactive Control Framework For Commercial And Residential Buildings, Min Gyung Yu, Gregory Pavlak
Assessing The Value Of Uncertainty-Aware Transactive Control Framework For Commercial And Residential Buildings, Min Gyung Yu, Gregory Pavlak
International High Performance Buildings Conference
With the increasing adoption of renewable energy and electric vehicles in the power grid, dealing with uncertainty in both supply and demand is critical to ensuring reliable and efficient operations. In this study, we discuss the value of a twostage stochastic control framework for an aggregator to address such problems by promoting improved decisionmaking and performance despite inherent uncertainty. An uncertaintyaware transactive control framework was developed to account for uncertainties in future conditions due to occupancy patterns, weather conditions, onsite power generation, and realtime pricing schemes. In the dayahead period, the aggregator decides the electricity procurement plan considering the possible …
Analysis Of Automated Fault Detection And Diagnostics Records As An Indicator Of Hvac Fault Prevalence: Methodology And Preliminary Results, Amir Ebrahimifakhar, David Yuill, Amanda Smith, Jessica Granderson, Eliot Crowe, Yimin Chen, Hayden Reeve
Analysis Of Automated Fault Detection And Diagnostics Records As An Indicator Of Hvac Fault Prevalence: Methodology And Preliminary Results, Amir Ebrahimifakhar, David Yuill, Amanda Smith, Jessica Granderson, Eliot Crowe, Yimin Chen, Hayden Reeve
International High Performance Buildings Conference
Faults in commercial buildings can cause energy waste and other performance problems such as reduced occupant comfort, reduced equipment longevity, and increased noise. However, it is currently unknown how commonly faults occur in different equipment types. This paper describes a method to estimate the prevalence of faults in air handling units, air terminal units, and rooftop units and the use of three metrics for summarizing results. This method was developed by the authors as part of a study which includes data from several automated fault detection and diagnostics (AFDD) data providers, providing a large sample with a wide range of …
Fault “Auto-Correction” For Hvac Systems: A Preliminary Study, Guanjing Lin, Marco Pritoni, Yimin Chen, Christopher Weyandt, Raphael Vitti, Jessica Granderson
Fault “Auto-Correction” For Hvac Systems: A Preliminary Study, Guanjing Lin, Marco Pritoni, Yimin Chen, Christopher Weyandt, Raphael Vitti, Jessica Granderson
International High Performance Buildings Conference
A Fault Detection and Diagnostics (FDD) tool is a type of energy management and information system that is designed to continuously identify the presence of faults and efficiency improvement opportunities through a 1-way interface to the building automation system and application of automated analytics. It is estimated that 5-30% energy saving can be achieved by employing FDD tools and implementing efficiency measures based on FDD findings. Although the potential of this technology is high, actual savings are only realized when an operator takes an action to fix the problem. There is a subset of faults that can be potentially addressed …
Fault Detection And Diagnosis For Residential Hvac Systems Using Transient Cloud-Based Thermostat Data, Fangzhou Guo, Bryan P. Rasmussen
Fault Detection And Diagnosis For Residential Hvac Systems Using Transient Cloud-Based Thermostat Data, Fangzhou Guo, Bryan P. Rasmussen
International High Performance Buildings Conference
Fault detection and diagnosis (FDD) using aggregated smart thermostat data is a relatively new research field, but one with immediate practical application to residential indoor climate control. This paper analyzes a cloud-based dataset which contains thermostat history records of nearly 370,000 distinct residential HVAC systems in the U.S. The large, diverse, and growing dataset enables novel methods for detecting and diagnosing faults on systems with limited sensor data. This paper proposes a statistics-based FDD method for non-variable speed heat pump and air conditioning units, and demonstrates the effectiveness with several case studies. The proposed method identifies systems within a similar …
Elementary School Renovation To Achieve Net Zero Energy, Songhao Wu, Brian Tedeschi, Zach Schreiber, William J. Hutzel, Luciana Debs
Elementary School Renovation To Achieve Net Zero Energy, Songhao Wu, Brian Tedeschi, Zach Schreiber, William J. Hutzel, Luciana Debs
International High Performance Buildings Conference
No abstract provided.
Cfd Analysis Of A Twin Screw Compressor With Oil Injection, Junfeng Wang, Hui Ding, Sham Rane, Ahmed Kovacevic
Cfd Analysis Of A Twin Screw Compressor With Oil Injection, Junfeng Wang, Hui Ding, Sham Rane, Ahmed Kovacevic
International Compressor Engineering Conference
In this paper, a full 3D transient Computational Fluid Dynamics (CFD) model of a twin screw compressor with oil injection is described in detail. Volume of Fluid (VOF) two phase flow model is used for gas and liquid phases. The rotor meshes are generated by SCORGTM grid generator and read into the CFD solver at each time step. The simulation runs efficiently and results are obtained in about 12 hours on 24 CPU cores. The CFD prediction of air mass flow rate and indicated power has a good agreement with the experimental data measured at City University of London. The …
Mechanistic Force Analysis Of Single-Screw Compressor With 6-11 Geometry Configuration, Haotian Liu, Ashvin Dhunput, Harry Miyamura, Terry Young, Dominic Lafford, Eckhard Groll, Davide Ziviani
Mechanistic Force Analysis Of Single-Screw Compressor With 6-11 Geometry Configuration, Haotian Liu, Ashvin Dhunput, Harry Miyamura, Terry Young, Dominic Lafford, Eckhard Groll, Davide Ziviani
International Compressor Engineering Conference
In commercial andindustrial Heating, Ventilating, Air Conditioning & Refrigeration(HVAC&R) applications, single-screw compressors have been widely used and proven to be efficient, reliable and economical in various operating conditionsand capacity ranges. The efficiency of single-screw compressor depends on several factors, includingthe pressure ratio, volume ratio, and leakage flows as well as frictional, heat and mechanical losses. Thus, estimating forcesand momentsplay animportant role with respect to reducingmechanical losses. Itis alsocritical to the reliability and safe operation of the machine. In this paper,a detailed mechanistic model of a 6-11 configuration single-screw compressor is described. The model is used to investigate the impact of …
The Thermodynamic Behavior Of Low-Gwp Zeotropic Mixtures On Water-Source Heat Pump Equipment, Saad Saleem, Craig R. Bradshaw
The Thermodynamic Behavior Of Low-Gwp Zeotropic Mixtures On Water-Source Heat Pump Equipment, Saad Saleem, Craig R. Bradshaw
International Refrigeration and Air Conditioning Conference
Regulatory changes, aimed at mitigating climate change, are forcing air-conditioning and heat pump manufacturers to change refrigerants in their products, including all Water-Source Heat Pumps (WSHPs). These changes require substantive changes to WSHP equipment design in order to continue to deliver heat pumps that meet product specifications and energy efficiency regulations. Some of the proposed low-GWP refrigerants to replace R410A, such as R452B and R454A, are zeotropic mixtures of refrigerants. Zeotropes with a significant glide may be taken advantage of in the refrigerant-to-water heat exchanger in a WSHP to improve overall system efficiency. However, there is a potential to also …
Demonstration Of A Load-Based Testing Methodology For Rooftop Units With Integrated Economizers, Parveen Dhillon, W. Travis Horton, James E. Braun
Demonstration Of A Load-Based Testing Methodology For Rooftop Units With Integrated Economizers, Parveen Dhillon, W. Travis Horton, James E. Braun
International Refrigeration and Air Conditioning Conference
Current performance evaluation approaches for commercial packaged air conditioning and heat pump equipment (e.g. AHRI 340/360) utilize full-load steady-state performance tests to estimate system EER (energy efficiency ratio) at different ambient conditions and part-load steady-state tests to estimate an IEER (integrated energy efficiency ratio), a figure of merit for system part-load performance. There are some limitations of the current testing approaches and performance metric estimations, including that they do not consider the effects of: 1) test unit embedded controls and their realistic interactions with the building load; 2) different climate zones and building types; and 3) economizer operation. As a …
A Trajectory Piecewise-Linear Approach To Model Order Reduction Of Vapor Compression Cycles, Jiacheng Ma, Donghun Kim, James E. Braun
A Trajectory Piecewise-Linear Approach To Model Order Reduction Of Vapor Compression Cycles, Jiacheng Ma, Donghun Kim, James E. Braun
International Refrigeration and Air Conditioning Conference
This paper presents a reduced order modeling approach for dynamic vapor compression cycles (VCC) based on a trajectory piecewiselinear (TPWL) approximation and Proper Orthogonal Decomposition (POD). Unlike other model order reduction techniques that apply to nonlinear dynamic heat exchanger (HX) models, the TPWL approach first represents a finite volume HX model with a weighted combination of linearized models along some state trajectories. Linearization points are selected by the kmeans clustering algorithm, which enables control of the number of linearized pieces. Then, each of the full order linear pieces is reduced by projection onto a POD basis to form a reduced …
Modelling And Simulation Of A Flash Tank Vapour Injection Heat Pump In Several Platforms, Viren Bhanot, Paolo Petagna, Andrea Cioncolini, Jiazhen Ling, Vikrant Aute
Modelling And Simulation Of A Flash Tank Vapour Injection Heat Pump In Several Platforms, Viren Bhanot, Paolo Petagna, Andrea Cioncolini, Jiazhen Ling, Vikrant Aute
International Refrigeration and Air Conditioning Conference
In this paper, we model a relatively complex flash tank vapour injection heat pump using the physical modelling software EcosimPro. The heat pump was extensively tested in a previous study and a variety of system parameters were made available for validation. Simulation results are compared against measured data as well as against two other platforms: Dymola and Simulink. Startup and step-change transients have been simulated. The discrepancies between the different models are used to highlight some important aspects in conducting dynamic thermo-fluid simulations. In particular, although qualitatively representative trends may be reproduced, there is an unavoidable need to first obtain …
Numerical Investigation Of Two-Stage Vapor Compression System With Simultaneous Vapor And Liquid Injection, Ransisi Huang, Jiazhen Ling, Vikrant Aute, Leping Zhang
Numerical Investigation Of Two-Stage Vapor Compression System With Simultaneous Vapor And Liquid Injection, Ransisi Huang, Jiazhen Ling, Vikrant Aute, Leping Zhang
International Refrigeration and Air Conditioning Conference
Two-stage vapor compression systems can be advantageous over single-stage systems by providing improved system performance, lower discharge temperature and reduced throttling losses. These systems employ various intermediate configurations, such as liquid injection and vapor injection. This paper presents a configuration for a R1234ze(E) two-stage air-conditioning system using a turbo compressor with two injection ports, one for vapor injection and the second for liquid injection. The liquid injection is used to cool the motor and electronics. A component-based representation and solution approach was used to simulate the two-stage compression system with simultaneous vapor and liquid injection at steady state. The turbo …
A Gray-Box Dynamic Modeling Method For Variable Speed Direct Expansion Systems, Haopeng Liu, Jie Cai
A Gray-Box Dynamic Modeling Method For Variable Speed Direct Expansion Systems, Haopeng Liu, Jie Cai
International Refrigeration and Air Conditioning Conference
In this paper, a gray-box dynamic modeling approach for variable-speed direct-expansion systems is presented. The overall approach incorporates a multi-stage training procedure that consists of 1) identification of component sub-models from quasi-steady-state performance data, 2) system model integration with estimation of refrigerant charge and 3) fine tuning of thermal capacitances of the evaporator and condenser to capture the system dynamic responses. Compared to traditional physics-based models, the proposed modeling approach has advantages including reduced engineering efforts in the model development phase, improved computational efficiency and reduced uncertainties. The modeling method was applied to a 3-ton variable-speed heat pump and proved …
Two-Phase Heat Transfer Of Low Gwp Ternary Mixtures, Marco Azzolin, Arianna Berto, Stefano Bortolin, Davide Del Col
Two-Phase Heat Transfer Of Low Gwp Ternary Mixtures, Marco Azzolin, Arianna Berto, Stefano Bortolin, Davide Del Col
International Refrigeration and Air Conditioning Conference
Refrigerant blends obtained mixing hydrofluorocarbons (HFC) and hydrofluoroolefins (HFO) have recently been proposed as substitutes for high GWP (Global Warming Potential) fluids employed in refrigeration and air-conditioning systems. As a general trend, the dimension of pipes used in heat exchangers is decreasing: diameters around 5 mm are often employed in finned-tube coil heat exchangers and minichannels heat exchangers (with internal diameter around 1-2 mm) are also a common solution for the automotive sector and for air-cooled chillers. Condensation and flow boiling heat transfer coefficients of zeotropic ternary mixtures R455A (R32, R1234yf and R744 at 21.5/75.5/3.0% by mass composition) and R452B …
Development Of Novel Experimental Infrastructure For Collecting High-Fidelity Experimental Data For Refrigerant To Air Heat Exchangers, Saad Saleem, Omer Sarfraz, Craig R. Bradshaw, Christian K. Bach
Development Of Novel Experimental Infrastructure For Collecting High-Fidelity Experimental Data For Refrigerant To Air Heat Exchangers, Saad Saleem, Omer Sarfraz, Craig R. Bradshaw, Christian K. Bach
International Refrigeration and Air Conditioning Conference
Manufactures of fin-and-tube heat exchangers often employ predictive modelling tools in order to reduce development cost and time. These tools require high-fidelity experimental data to validate the accuracy of their predictions. To that end, this paper presents the design and development of a custom-designed pumped refrigerant loop to collect high-fidelity experimental data for fin-and-tube heat exchangers in three operating modes: (1) single-phase refrigerant, (2) evaporator, and (3) condenser mode. It is combined with a small-scale wind tunnel installed in a psychrometric chamber facility for the purpose of validating the recently developed discretized fin-and-tube heat exchanger models (Sarfraz et al., 2019a …
Effect Of Flow Regime Before Distributor On Two-Phase Flow Distribution, Yufang Yao, Pega Hrnjak
Effect Of Flow Regime Before Distributor On Two-Phase Flow Distribution, Yufang Yao, Pega Hrnjak
International Refrigeration and Air Conditioning Conference
Conical refrigerant distributors are usually used to improve the distribution of two-phase flow to each circuit of the DX evaporators. A nozzle is commonly added before a cone to homogenize two-phase flow and that way unify distribution among channels. However, when the nozzle is not properly sized or, in some cases, there is no nozzle, the distributor performance is much affected by the flow regimes at the distributor inlet. This paper presents the effect of the flow regime at the distributor inlet on the uniformity of two-phase flow distribution. In this case, the flow regime is determined by mass flux, …