Open Access. Powered by Scholars. Published by Universities.®
- Discipline
-
- Social and Behavioral Sciences (11626)
- Library and Information Science (8974)
- Engineering (6329)
- Physical Sciences and Mathematics (2868)
- Arts and Humanities (2752)
-
- Civil and Environmental Engineering (2550)
- Computer Sciences (2077)
- Education (1983)
- Civil Engineering (1879)
- Life Sciences (1669)
- Comparative Literature (1407)
- Communication (854)
- Medicine and Health Sciences (725)
- Rhetoric and Composition (694)
- Feminist, Gender, and Sexuality Studies (680)
- American Studies (667)
- Film and Media Studies (638)
- Mechanical Engineering (619)
- European Languages and Societies (607)
- Reading and Language (606)
- Critical and Cultural Studies (594)
- Agriculture (585)
- Other Arts and Humanities (585)
- Psychology (552)
- Plant Sciences (546)
- Nanoscience and Nanotechnology (541)
- Theatre and Performance Studies (539)
- Other Film and Media Studies (522)
- Television (509)
- Business (488)
- Keyword
-
- Applied sciences (587)
- Comparative literature (498)
- comparative literature (488)
- Comparative cultural studies (303)
- comparative cultural studies (297)
-
- Education (220)
- Social sciences (205)
- Biological sciences (195)
- Information literacy (170)
- Pure sciences (160)
- Cultural studies (155)
- Simulation (154)
- Vegetables (153)
- cultural studies (152)
- Variety trials (147)
- Literary theory (136)
- literary theory (135)
- Construction (120)
- Optimization (118)
- Health and environmental sciences (117)
- Sustainability (106)
- CFD (95)
- Safety (94)
- Economics (92)
- Problem-based learning (92)
- Zea mays (92)
- Modeling (90)
- Mechanics (87)
- Concrete (86)
- Heat transfer (85)
- Publication Year
- Publication
-
- Against the Grain (7173)
- Purdue Road School (3846)
- International Compressor Engineering Conference (2764)
- International Refrigeration and Air Conditioning Conference (2681)
- Open Access Dissertations (2120)
-
- JTRP Technical Reports (1905)
- Department of Computer Science Technical Reports (1777)
- Open Access Theses (1616)
- CLCWeb: Comparative Literature and Culture (1418)
- Proceedings of the IATUL Conferences (1358)
- Historical Documents of the Purdue Cooperative Extension Service Archive (1121)
- Department of Physics and Astronomy Faculty Publications (1038)
- The Writing Center Journal (1028)
- Charleston Library Conference (939)
- The Summer Undergraduate Research Fellowship (SURF) Symposium (884)
- Department of Electrical and Computer Engineering Technical Reports (747)
- The Journal of Purdue Undergraduate Research (683)
- Society of Engineering Science 51st Annual Technical Meeting Archive (652)
- First Opinions, Second Reactions (609)
- CIB Conferences (503)
- International High Performance Buildings Conference (495)
- LARS Symposia (491)
- Birck and NCN Publications (488)
- Education and Culture (431)
- International Conference on Durability of Concrete Structures (359)
- CTRC Research Publications (353)
- Libraries Faculty and Staff Scholarship and Research (294)
- Midwest Vegetable Trial Reports (288)
- Publications of the Ray W. Herrick Laboratories (286)
- Journal of Southeast Asian American Education and Advancement (274)
- Publication Type
Articles 6451 - 6480 of 50088
Full-Text Articles in Entire DC Network
Developing A Framework For Determining Optimum Dispatch Of Energy To A Building From Conventional And Renewable Sources, Sultan Ahmad, William Travis Horton
Developing A Framework For Determining Optimum Dispatch Of Energy To A Building From Conventional And Renewable Sources, Sultan Ahmad, William Travis Horton
International High Performance Buildings Conference
In an optimally designed grid-connected system with distributed energy resources where the grid plays the role of an energy buffer, it is interesting to analyze the economic feasibility to employ energy storage systems. A grid-connected system synchronizes with the power fluctuations, lowering the costs of energy compared to the cost of using conventional energy storage systems. An adaptive code is developed using computer programming that is used for lifetime simulation of the energy dispatch system with a specified time step and for optimization algorithm with comprehensive reliability/cost assessment. The results can be extended to a long period considering various economic …
The Role Of Occupant Behavior Models In Multi-Objective Optimization Analysis, Julian Donges, Alessandro Prada, Francesca Cappelletti, Andrea Gasparella
The Role Of Occupant Behavior Models In Multi-Objective Optimization Analysis, Julian Donges, Alessandro Prada, Francesca Cappelletti, Andrea Gasparella
International High Performance Buildings Conference
Building retrofit design aims at achieving a certain low energy target at a minimum cost. However, these buildings tend to be less comfortable than expected, prone to overheating, poor air quality, and less resilient towards different user profiles. Even when more accurate simulation models are used to calculate the energy demand, occupant behavior is usually oversimplified as a static schedule or rule-based model which often does not depend on comfort conditions and does not represent the actual occupants’ reactions to manage indoor comfort. This can cause a significant gap between the simulated and the measured building performance. To address this …
Refrigerant- Lubricant Mixture Properties Influencing Bubble Dynamic Parameters And Heat Transfer Coefficient In Nucleate Pool Boiling, Jung-Tsung Hung, Yu-Kai Chen, Hou-Kuang Shih, Chi-Chuan Wang
Refrigerant- Lubricant Mixture Properties Influencing Bubble Dynamic Parameters And Heat Transfer Coefficient In Nucleate Pool Boiling, Jung-Tsung Hung, Yu-Kai Chen, Hou-Kuang Shih, Chi-Chuan Wang
International Refrigeration and Air Conditioning Conference
We have been successfully developed a model regarding lubricant effect on individual processes of bubble nucleation, growth and departure period for nucleate pool boiling heat transfer. In this study, three type POE refrigeration lubricants with different refrigerant miscibility (POEA/POEB/POEC), two viscosity grades (ISO68 & 170), three kind of refrigerants (R-134a/R-1234ze/R-134yf), and three different saturated temperatures (10℃/0℃/10℃) are taken into calculation under different heat flux ranging from 10 KW/m2 to 80 KW/m2. Based on this model, a knowledge of chemical structures and physical properties of lubricant and refrigerant is sufficient to get bubble dynamic parameters and predict the boiling performance near …
Reduced Gwp Refrigerant For Residential And Commercial Air Conditioning Systems, Kaimi Gao, Henna Tangri, Greg Smith, Ankit Sethi, Samuel Yana Motta, Ryan Hulse
Reduced Gwp Refrigerant For Residential And Commercial Air Conditioning Systems, Kaimi Gao, Henna Tangri, Greg Smith, Ankit Sethi, Samuel Yana Motta, Ryan Hulse
International Refrigeration and Air Conditioning Conference
R-410A is widely used in residential and light commercial air-conditioning, heat pump and chiller systems. Due to increasing concerns about climate change, various environmental regulations have been proposed to phase out this refrigerant. A new refrigerant, R-466A, has been developed, which offers high energy efficiency and low global warming potential (GWP), resulting in low overall environmental impact. This paper discusses the thermal properties as well as the performance of this new refrigerant in a representative air conditioning system showing the benefits of using this new refrigerant. The thermal stability, material compatibility and refrigerant/lubricant interactions of R-466A are also discussed. Finally, …
Hvac Systems With Low Global Warming Potential Refrigerants: A Case Study, Vijay Bahel, Rajan Rajendran, Brian Butler, Drew Welch
Hvac Systems With Low Global Warming Potential Refrigerants: A Case Study, Vijay Bahel, Rajan Rajendran, Brian Butler, Drew Welch
International Refrigeration and Air Conditioning Conference
The objective of this case study is three-fold: (1) identify promising alternative refrigerants with lower global warming potential (GWP); (2) among those, select refrigerant(s) that could be “drop-in” replacements for R-410A and would not require significant system redesign or compressor changes — with the exception of minimal changes such as lubricating fluid and expansion valves; (3) evaluate the impact of another easy-to-implement option: replacing lower-efficiency, permanently split capacitor (PSC) condenser fans and evaporator blower motors with electronically commutated motors (ECM) for additional system efficiency improvements. This study leverages the steady-state heat pump design model (HPDM) developed by the Department of …
Differential Mass Measurement Scale For Measuring Refrigerant Charge And Oil Retention Of Round Tube Plate Fin Heat Exchangers (Ashrae Rp-1785), Abraham J. Lee, Christian K. Bach, Craig R. Bradshaw
Differential Mass Measurement Scale For Measuring Refrigerant Charge And Oil Retention Of Round Tube Plate Fin Heat Exchangers (Ashrae Rp-1785), Abraham J. Lee, Christian K. Bach, Craig R. Bradshaw
International Refrigeration and Air Conditioning Conference
During the product development process of split-system air-conditioning units, simulation models are widely used by manufacturers to predict equipment performance. Model-based development allows manufacturers to reduce the number of experiments prior to product launch, reducing product development cycle time and cost. However, the current models struggle to predict performance for reversible heat pump systems because of inaccurate predictions of refrigerant charge and oil retention. This is due to a lack of validation data for R410A charge models. This study provides high-quality reference data for refrigerant and oil charge measurements in residential fin-tube heat exchangers operating with R410A. This high-quality reference …
Correlation For Flow Boiling Heat Transfer Of Low-Pressure Refrigerants Inside A Horizontal Smooth Tube, Yufei Liu, Daisuke Jige, Norihiro Inoue
Correlation For Flow Boiling Heat Transfer Of Low-Pressure Refrigerants Inside A Horizontal Smooth Tube, Yufei Liu, Daisuke Jige, Norihiro Inoue
International Refrigeration and Air Conditioning Conference
The flow boiling heat transfer of low-pressure refrigerants including R1224yd(Z), R1233zd(E), R1336mzz(Z), and R1336mzz(E) was experimentally investigated inside a horizontal smooth tube with outer and inner diameters of 9.52 and 8.40 mm, respectively. The experiments were conducted at a mass velocity range of 50–300 kgm−2s−1 and a saturation temperature of 40 °C. In the forced convection region, where the vapor shear force was dominant, the measured heat transfer coefficients were slightly larger than those of the conventional refrigerants were. A modified heat transfer correlation was developed based on a wettability separation angle to differentiate the stratified and annular flows. In …
Characterization Of Mos Sensors For R-32 And R-454b Leaks, James R. Leahy, Garrett J. Wack, Marcin Piech, Michael J. Birnkrant, Peter B. Sunderland
Characterization Of Mos Sensors For R-32 And R-454b Leaks, James R. Leahy, Garrett J. Wack, Marcin Piech, Michael J. Birnkrant, Peter B. Sunderland
International Refrigeration and Air Conditioning Conference
Owing to concerns about climate change, many jurisdictions are phasing out high global warming potential refrigerants in HVAC&R systems. Their near-term replacements are class A2L (mildly-flammable) refrigerants. Area monitoring detectors will be required for most future residential, commercial, and industrial HVAC systems that use these refrigerants. UL Standard 60335-2-40 requires these detectors to have a set-point of 25% of the lower flammability limit (LFL) and to detect the set-point within 10 s when exposed to a gas mixture at the LFL. Inexpensive detectors that meet these requirements do not exist, which has delayed the adoption of A2L refrigerants. A technology …
Design Of Capacitive Sensors For Measuring Void Fraction In Headers Of Microchannel Heat Exchangers, Hongliang Qian, Pega Hrnjak
Design Of Capacitive Sensors For Measuring Void Fraction In Headers Of Microchannel Heat Exchangers, Hongliang Qian, Pega Hrnjak
International Refrigeration and Air Conditioning Conference
This paper presents the design and building of capacitive sensors for measuring void fraction in headers of microchannel heat exchangers with R134a. The capacitive sensors utilize different electrical properties (dielectric constant) between the liquid and vapor phases to measure the void fraction of two-phase flow. The test section (a header) is made of 3D printed partitions with a total length of 185.8 mm and an inner diameter of 15.8 mm (D). It has eleven microchannel-tube protrusions with a depth of half inner diameter. All microchannel tubes are capable of being connected to real aluminum tube-like real heat exchangers in the …
Effect Of Orientation On Performance Of The Refrigerant Distributor, Yufang Yao, Pega Hrnjak
Effect Of Orientation On Performance Of The Refrigerant Distributor, Yufang Yao, Pega Hrnjak
International Refrigeration and Air Conditioning Conference
Maldistribution of refrigerant two-phase flow in a DX evaporator is almost inevitable in real application because of the different properties of liquid and vapor. One of the main reasons for this is phase separation due to the effect of gravity. For vertical orientation, the influence of gravity on the operation of distributors is small. However, horizontal installation is more likely to be affected by gravity when the flow is not homogeneous. This paper presents an evaluation of the performance of a refrigerant distributor at three different orientations: horizontal, vertical upwards, and downwards. For each direction, the expansion device, distributor, and …
Chemical Stability And Equipment Reliability Impacts Of R-13i1 (Cf3i) In R-466a, Stephen Anthony Kujak, Elyse Sorenson
Chemical Stability And Equipment Reliability Impacts Of R-13i1 (Cf3i) In R-466a, Stephen Anthony Kujak, Elyse Sorenson
International Refrigeration and Air Conditioning Conference
Recently a new blend, R-466A, utilizes R-13I1 (trifluoroiodomethane, CF3I) in a blend with R-32 and R-125 that ASHRAE Standard 34 classified as A1 (lower toxicity and nonflammable) which is the same safety classification as R-410A. R-466A has been shown to have similar performance and capacity to R-410A, but with only 1/3 of the GWP as compared to R-410A. R-13I1 is not a new molecule. It was considered in the CFC (chlorofluorocarbon)/HCFC (hydrochlorofluorocarbon) to HFC (hydrofluorocarbon) transition period, but was abandoned because of chemical stability concerns. The iodine atom in the molecule drives the instability concerns. Halogenated refrigerant chemical stability generally …
Comparison Of Steady-State And Dynamic Load-Based Performance Evaluation Methodologies For A Residential Air Conditioner, Parveen Dhillon, W. Travis Horton, James E. Braun
Comparison Of Steady-State And Dynamic Load-Based Performance Evaluation Methodologies For A Residential Air Conditioner, Parveen Dhillon, W. Travis Horton, James E. Braun
International Refrigeration and Air Conditioning Conference
Space cooling and heating equipment account for nearly 32% of the total residential electricity consumption in the U.S. In the residential space conditioning equipment market, air-conditioning and heat-pumping systems are prevalent, so even a slight improvement in these system efficiencies can have a significant impact on reducing the overall energy consumption. Over the years, the energy efficiency benchmarks established by the U.S. Department of Energy have been successful in encouraging manufacturers to develop higher efficiency equipment. These benchmarks are based on an energy efficiency standard, and these standards are based on a rating test procedure that forms the technical basis. …
Heat-Pump Control Design Performance Evaluation Using Load-Based Testing, Jie Ma, Parveen Dhillon, W. Travis Horton, James E. Braun
Heat-Pump Control Design Performance Evaluation Using Load-Based Testing, Jie Ma, Parveen Dhillon, W. Travis Horton, James E. Braun
International Refrigeration and Air Conditioning Conference
Space heating is one of the primary components of residential energy usage in the U.S., accounting for nearly 43% (EIA, 2015) of the total residential energy consumption. To reduce this energy usage, heat-pumps provide an energy-efficient alternative to currently prevalent systems such as electric heaters and gas furnaces. Advanced control strategies have the potential to further improve heat-pump system energy efficiency and comfort delivery. In recent years, advancements in the microprocessor field have made it possible to widely implement advanced energy-efficient controls within heat-pump systems. However, still only a very small fraction of residential air-conditioners and heat-pumps currently sold in …
Very Low Gwp Refrigerant R-516a For R-134a Replacement In Commercial Refrigeration, Sarah Kim, Kris Crosby, Damien Rodowski
Very Low Gwp Refrigerant R-516a For R-134a Replacement In Commercial Refrigeration, Sarah Kim, Kris Crosby, Damien Rodowski
International Refrigeration and Air Conditioning Conference
Efforts continue to find alternative next generation refrigerants with low environmental impact. While Global Warming Potential (GWP) is an easy indicator to screen for refrigerants with low direct CO2 emissions, there are other important aspects to consider such as safety, performance, compatibility, stability, etc. Among the different sectors within the HVAC&R industry, the refrigeration sector is experiencing earlier transition compared to some of the other applications due to relatively high GWP of the incumbent refrigerants such as R-404A and R-134a. R-516A, which is a mildly flammable (A2L) azeotropic refrigerant with GWP of 131 (AR5) and is a near drop-in of …
Mass Measurement, Visualization And Signal Pattern Based Calibration Of Capacitive Sensors For Measuring Void Fraction In Headers, Hongliang Qian, Pega Hrnjak
Mass Measurement, Visualization And Signal Pattern Based Calibration Of Capacitive Sensors For Measuring Void Fraction In Headers, Hongliang Qian, Pega Hrnjak
International Refrigeration and Air Conditioning Conference
This paper presents the calibration procedures of the capacitive sensors for measuring void fraction in headers with R134a. The sensors utilize the difference of dielectric constants between the liquid and vapor phases of the two-phase mixture. The 3D printed header has eleven microchannel-tube protrusions. Eleven capacitive sensors are located between protrusions. All sensors are made to be identical as much as possible in the manual fabrication procedures. Because the electric field within each sensor is not perfectly uniform, sensors need to be calibrated before measuring void fraction. Another transparent 3D printed header with the same inner geometry is installed at …
Optimization Of Refrigerant Compositions For Low-Gwp Refrigerant Mixtures Using Segment-By-Segment Heat Exchanger And Detailed System Models, Zhenning Li, Bo Shen, Kyle Gluesenkamp
Optimization Of Refrigerant Compositions For Low-Gwp Refrigerant Mixtures Using Segment-By-Segment Heat Exchanger And Detailed System Models, Zhenning Li, Bo Shen, Kyle Gluesenkamp
International Refrigeration and Air Conditioning Conference
The recently introduced hydrofluoroolefin (HFO) refrigerants, including R1234yf and R1234ze(E), have significantly lower global warming potentials (GWPs) than traditional hydrofluorocarbon (HFC) refrigerants like R410A. However, prior tests show that direct drop-in of pure R1234yf or R1234ze(E) into equipment designed for R410A results in a decrease in heat exchanger capacity and the system coefficient of performance. The primary reason is the lower in-tube heat transfer performance of R1234yf and R1234ze(E) compared with that of R410A. To address this issue, previous studies have mixed the mildly flammable HFC R32 with HFOs to improve system performance, with HFC R125 also added to suppress …
Alternate Refrigerants For Heat Pump Water Heater Applications- Opportunities And Challenges, Kashif Nawaz, Bo Shen, Ahmed Elatar, Van Baxter, Omar Abdelaziz
Alternate Refrigerants For Heat Pump Water Heater Applications- Opportunities And Challenges, Kashif Nawaz, Bo Shen, Ahmed Elatar, Van Baxter, Omar Abdelaziz
International Refrigeration and Air Conditioning Conference
Growing awareness of the potential environmental impacts of conventional refrigerants (CFCs and HFCs) has led to efforts to identify suitable alternative refrigerants for various heat pump applications with minimum environmental impact. This study is focused on the performance evaluation of various alternatives including hydrocarbon (HC), hydroflouroolefins (HFO), and CO2 as drop-in-replacement for R134a for heat pump water heating (HPWH). Fundamental thermophysical properties have been used to highlight the important performance characteristics of the systems when such fluids are deployed working medium. Key performance parameters such as unified energy factor, first hour rating and thermal stratification in the water tank are …
Experimental Investigation Of A Heat Pump Tumble Dryer With A Zeotropic Refrigerant Blend, Melanie Cop, Christiane Thomas, Ullrich Hesse
Experimental Investigation Of A Heat Pump Tumble Dryer With A Zeotropic Refrigerant Blend, Melanie Cop, Christiane Thomas, Ullrich Hesse
International Refrigeration and Air Conditioning Conference
The restrictions on the use of hydrofluorocarbons with a high global warming potential (GWP) are increasing on a global scale. They can be cost-driven or politically enforced. In Europe, the EU regulation 517/2014 restricts the refrigerants currently used in household appliances, such as R-134a, so new systems and working fluids must be investigated as replacements. The trend in domestic appliances with heat pumps, such as tumble dryers, is towards using propane as a refrigerant. This paper presents an experimental comparison of different refrigerants in a heat pump tumble dryer test rig. The original working fluid is R-134a, and the tests …
Experimental Observation Of Flow Regimes And Flow-Induced Noise Near The Expansion Device With Different Installation Orientations, Yingyue Zhang, Stefan Elbel
Experimental Observation Of Flow Regimes And Flow-Induced Noise Near The Expansion Device With Different Installation Orientations, Yingyue Zhang, Stefan Elbel
International Refrigeration and Air Conditioning Conference
The flow-induced noise can be very disturbing to the users in the HVAC&R system. The flow-induced noise varies with the flow regimes near the expansion device, especially related to the flow regimes before entering the expansion device. The flow regimes are not only related to the mass flow rate of the flow and the quality of the flow but also related to the gravity orientation of the flow. Therefore, the flow regimes in the tube with different orientations can be different. In this paper, the comparison of the psychoacoustic annoyance of flow-induced noise with different needle valve installations is studied. …
Effect Of The Refrigerant Charge On The System Performance And Mass Distribution In Air-To-Water Heat Pumps, Costantino Guzzardi, Marco Azzolin, Sandro Lazzarato, Davide Del Col
Effect Of The Refrigerant Charge On The System Performance And Mass Distribution In Air-To-Water Heat Pumps, Costantino Guzzardi, Marco Azzolin, Sandro Lazzarato, Davide Del Col
International Refrigeration and Air Conditioning Conference
Recent regulations in the matter of climate change and environmental protection are pushing to reduce the release of greenhouse gases into the atmosphere. The overall environmental impact of a refrigeration system can be reduced by optimizing and possibly minimizing the amount of refrigerant charge in the system. Even in the case of natural and low-GWP synthetic refrigerants, due to the well-known problems with toxicity and flammability, it is required to minimize the amount of refrigerant charged into the system to reduce the associated risks. The charge minimization process requires to know the refrigerant distribution to identify and redesign the critical …
Selection Of Twin Screw Compressor Economizer Port Location To Optimize Unit Efficiency, Tasha Williams, Matthew Cambio
Selection Of Twin Screw Compressor Economizer Port Location To Optimize Unit Efficiency, Tasha Williams, Matthew Cambio
International Compressor Engineering Conference
Twin screw compressors are widely used in many applications. The performance limits of screw compressors are continuously being pushed to meet increased demand for energy efficiency. Several design adjustments can be made to the compressor to create a more efficient unit, such as the proper design of an economizer. The economizer is a port where refrigerant vapor is (re-)injected. General compressor effects of using an economizer are increase in compressor power, increase in discharge mass flow, and reduction of isentropic efficiency. However, the unit experiences an increase in refrigeration capacity and efficiency. The use of economizers for screw compressors is …
A Whole Building Life-Cycle Assessment Approach To Support Decision-Making For Sustainable Buildings, Hao Zhang, Jie Cai, James E. Braun
A Whole Building Life-Cycle Assessment Approach To Support Decision-Making For Sustainable Buildings, Hao Zhang, Jie Cai, James E. Braun
International High Performance Buildings Conference
Buildings account for 39% of the CO2 emissions in the U.S. Although emerging building energy-efficient technologies lead to improved energy efficiency and lower environmental impact in the operational phase, not much attention has been paid to the environmental impact associated with the materials and manufacturing of the building mechanical systems. This paper presents an integrated life-cycle assessment method for buildings that accounts for the embodied and use phase carbon impacts of the building and its mechanical systems. The proposed methodology relies on EnergyPlus to generate the use-phase energy consumption for any given building. A material 'grabber' routine was developed to …
Development Of A Shoeboxing Approach For Urban Building Energy Modeling, Federico Battini, Giovanni Pernigotto, Andrea Gasparella
Development Of A Shoeboxing Approach For Urban Building Energy Modeling, Federico Battini, Giovanni Pernigotto, Andrea Gasparella
International High Performance Buildings Conference
Urban Building Energy Modeling aims at assessing the building energy performance at city scale with as little computational effort as possible. Thus, different methods have been developed in the last years to reduce the required calculation time by simplifying the modeling approach, selecting only representative buildings, or minimizing the building description. Starting from the latter ones, this work proposes a novel algorithm capable of abstracting a randomly shaped building into a representative shoebox. The presented shoebox generation algorithm is based on a preliminary sensitivity screening analysis on a set of reference parallelepiped-shaped thermal zones. This allowed the identification of the …
Measurement Of Film Thickness And Temperature On Horizontal Metal Spray Coated Tube Falling Film Evaporator Using Interferometric Techique, Akhil Krishnan Maliackal, Ganesan A R, Mani Annamalai
Measurement Of Film Thickness And Temperature On Horizontal Metal Spray Coated Tube Falling Film Evaporator Using Interferometric Techique, Akhil Krishnan Maliackal, Ganesan A R, Mani Annamalai
International Refrigeration and Air Conditioning Conference
’Water’ is the ’Essence of Life’. It is an irreplaceable precious resource that is core of life on earth, a vital commodity that is critical for human survival, socio-economic developments and for the preservation of a healthy ecosystem. Current trends indicate that two-thirds of the world’s population will be living in water-stressed countries by 2025(wat (2006)). In order to eradicate or to provide sufficient water requirement for mankind desalination plays a pivotal role. This paper presents studies on horizontal tube falling film evaporator for Multi effect desalination (MED) system with spray coated tubes. The most important component in any MED …
Evaluation Of Leak Detectors For Flammable Refrigerants (Ahrti #9014), Jiao Zheng, Stefan Elbel
Evaluation Of Leak Detectors For Flammable Refrigerants (Ahrti #9014), Jiao Zheng, Stefan Elbel
International Refrigeration and Air Conditioning Conference
As the HVAC&R industry is moving towards low-GWP refrigerants, many flammable working fluids are being considered. While these refrigerants perform quite well in terms of capacity and efficiency, the widespread use of flammable fluids will require changes to the way systems are designed and manufactured to address new safety codes and guidelines related to building design, HVAC&R installation and service requirements. This paper presents the results of a recently completed AHRTI study aimed at exploring the suitability of different leak detectors when exposed to A2L refrigerants. The sensing principles investigated include NDIR, micromachined membranes, MOS, and thermal conductivity-based sensors. R32 …
Measurement Of Condensation Heat Transfer And Pressure Drop For Zeotropic Mixture R-454c And Its Components R-32 And R-1234yf In A Horizontal Microfin Tubes, Ethan P. Matty, Brian M. Fronk
Measurement Of Condensation Heat Transfer And Pressure Drop For Zeotropic Mixture R-454c And Its Components R-32 And R-1234yf In A Horizontal Microfin Tubes, Ethan P. Matty, Brian M. Fronk
International Refrigeration and Air Conditioning Conference
This paper compares the condensation heat transfer and pressure drop for zeotropic refrigerant R454C and its individual components, R32 and R1234yf, in a horizontal microfin tube. The microfin tube has a 4 mm outer diameter, 0.18 mm wall thickness, and a surface area ratio of 1.56. HFOs and HFC/HFO blends like R454C have low global warming potential and can be alternatives to HFC refrigerants when retrofitting a system or producing new equipment. However, there is an additional mass transfer resistance present during phase change for a zeotropic mixture, which results in reduced heat transfer performance. Microfin tubes enhance heat transfer …
Application Of Computational Fluid Dynamics To The Lubrication Study Of An Oil-Injected Screw Compressor, Sheng-Hung Hsieh, Jin-Wei Zhang, Chi-Shun Huang
Application Of Computational Fluid Dynamics To The Lubrication Study Of An Oil-Injected Screw Compressor, Sheng-Hung Hsieh, Jin-Wei Zhang, Chi-Shun Huang
International Compressor Engineering Conference
Computational fluid dynamics and mesh generation tools have been well developed, and could be used to calculate the performance of an oil-injected screw compressor. Designers could now effectively obtain reliable results of efficiency, temperature, force and torque. Some physical phenomena inside a screw compressor are not easy to be observed through experiments, such as the oil distribution and the oil film thickness on the rotor surface. Under the ideal lubrication condition, the oil film of proper thickness should be maintained on the local surfaces which are going to contact with each other. This could be numerically explored by computational fluid …
A Cfd Investigation Of The Suction Process In A Screw Compressor, Matt Cambio, Scott Branch, Alberto Scala, Jonathan Harrison
A Cfd Investigation Of The Suction Process In A Screw Compressor, Matt Cambio, Scott Branch, Alberto Scala, Jonathan Harrison
International Compressor Engineering Conference
Computational fluid dynamics (CFD) has been widely applied to screw compressors. CFD has allowed engineers to gain a better understanding of the complex flows that occur inside the screw compressor. In many cases, the details revealed are only possible with CFD compared to 1-D simulations. Both CFD and 1D can reduce development costs and as in this case, guide decisions on the choice of hardware to be tested. This paper presents the flow details of the suction process in a screw compressor and the effects on performance. The cases presented are a twin screw rotor set applied to two different …
The Study On Dynamic Characteristics Of Twin-Screw Compressor Rotor, Baoshun Xiong, Huagen Wu, Kanlong Lin, Beiyu Zhang
The Study On Dynamic Characteristics Of Twin-Screw Compressor Rotor, Baoshun Xiong, Huagen Wu, Kanlong Lin, Beiyu Zhang
International Compressor Engineering Conference
In the working process of twin-screw compressor, the rotors are subjected to multiple physical effects of the gas temperature, pressure and force, and presents a periodic change. In this paper, three-dimensional Computational Fluid Dynamics (CFD) simulation of screw compressor is carried out, and the characteristics of temperature distribution, pressure distribution and gas force distribution on the rotors’ surface are studied. Firstly, the rotor domain, suction and exhaust face grids are generated by TwinMesh, and then they are imported into the CFX calculation model. Through the fluid-structure interaction analysis and calculation, the strain shape of the screw rotor under the multiple …
Energy Modeling And Energy Efficiency Opportunities For A Public Library Building In The Upper Peninsula Of Michigan, Amarnath Warty, Sunil Mehendale
Energy Modeling And Energy Efficiency Opportunities For A Public Library Building In The Upper Peninsula Of Michigan, Amarnath Warty, Sunil Mehendale
International High Performance Buildings Conference
Energy modeling tools have been extensively used for analyzing building performance as well as for assessing energy efficiency opportunities. The present research has a twofold aim: (1) to model the natural gas consumption and the total electricity consumption of a 12600 sq. ft. public library building in Houghton, MI, and (2) to identify any opportunities to improve energy efficiency. This was accomplished by first developing and validating an eQUEST model for the library building in conjunction with a linear regression model correlating the natural gas consumption (during winter) with heating degree days and the electricity consumption (during summer) as a …