Periodate and hypobromite modification of Southern pine wood to improve sorption of copper ion

Science.gov (United States)

James D. McSweeny; Roger M. Rowell; George C. Chen; Thomas L. Eberhardt; Min Soo-Hong

2008-01-01

Milled southern pine wood was modified with sequential treatments of sodium periodate and sodium hypobromite for the purpose of improving copper ion (Cu2+) sorption capacity of the wood when tested in 24-h equilibrium batch tests. The modified wood provided additional carboxyl groups to those in the native wood and substantially increased Cu2+ uptake over that of...

2016 German refrigeration and air conditioning meeting. Proceedings; Deutsche Kaelte- und Klimatagung 2016. Tagungsbericht

Energy Technology Data Exchange (ETDEWEB)

NONE

2016-07-01

The following topics were dealt with: Large cryogenic facilities, relief valves, liquid helium, liquid-nitrogen and liquid hydrogen cooling, new concepts, foundations and materials of the heat-pump techniques, evaporation, phase-change materials, absorption, afterheat usage, ionic liquids, sorption, condensers, heat exchangers, back-cooling systems, refrigerants, caron dioxide, mobile applications, efficiency and optimization, air conditioning.

Recent investigations on refrigerants for magnetic refrigerators

International Nuclear Information System (INIS)

Hashimoto, T.

1986-01-01

In development of the magnetic refrigerator, an important problem is selection of magnetic materials as refrigerants. The main purpose of the present paper is to discuss the magnetic and thermal properties necessary for these refrigerants and to report recent investigations. Magnetic refrigerants can be expediently divided into two groups, one for the Carnottype magnetic refrigerator below 20 K and the other for the Ericsson-type refrigerator. The required physical properties of refrigerants in each type of the magnetic refrigerator are first discussed. And then, the results of recent investigations on the magnetic, thermal and magnetocaloric characters of several promising magnetic refrigerants are shown. Finally, a brief prospect of the magnetic refrigerants and refrigerators is given

Design of refrigeration system using refrigerant R134a for macro compartment

Science.gov (United States)

Rani, M. F. H.; Razlan, Z. M.; Shahriman, A. B.; Yong, C. K.; Harun, A.; Hashim, M. S. M.; Faizi, M. K.; Ibrahim, I.; Kamarrudin, N. S.; Saad, M. A. M.; Zunaidi, I.; Wan, W. K.; Desa, H.

2017-10-01

The main objective of this study is to analyse and design an optimum cooling system for macro compartment. Current product of the refrigerator is not specified for single function and not compact in size. Hence, a refrigeration system using refrigerant R134a is aimed to provide instant cooling in a macro compartment with sizing about 150 × 150 × 250 mm. The macro compartment is purposely designed to fit a bottle or drink can, which is then cooled to a desired drinking temperature of about 8°C within a period of 1 minute. The study is not only concerned with analysing of heat load of the macro compartment containing drink can, but also focused on determining suitable heat exchanger volume for both evaporator and condenser, calculating compressor displacement value and computing suitable resistance value of the expansion valve. Method of optimization is used to obtain the best solution of the problem. Mollier diagram is necessary in the process of developing the refrigeration system. Selection of blower is made properly to allow air circulation and to increase the flow rate for higher heat transfer rate. Property data are taken precisely from thermodynamic property tables. As the main four components, namely condenser, compressor, evaporator and expansion valve are fully developed, the refrigeration system is complete.

Refrigerated Warehouse Demand Response Strategy Guide

Energy Technology Data Exchange (ETDEWEB)

Scott, Doug [VaCom Technologies, San Luis Obispo, CA (United States); Castillo, Rafael [VaCom Technologies, San Luis Obispo, CA (United States); Larson, Kyle [VaCom Technologies, San Luis Obispo, CA (United States); Dobbs, Brian [VaCom Technologies, San Luis Obispo, CA (United States); Olsen, Daniel [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

2015-11-01

This guide summarizes demand response measures that can be implemented in refrigerated warehouses. In an appendix, it also addresses related energy efficiency opportunities. Reducing overall grid demand during peak periods and energy consumption has benefits for facility operators, grid operators, utility companies, and society. State wide demand response potential for the refrigerated warehouse sector in California is estimated to be over 22.1 Megawatts. Two categories of demand response strategies are described in this guide: load shifting and load shedding. Load shifting can be accomplished via pre-cooling, capacity limiting, and battery charger load management. Load shedding can be achieved by lighting reduction, demand defrost and defrost termination, infiltration reduction, and shutting down miscellaneous equipment. Estimation of the costs and benefits of demand response participation yields simple payback periods of 2-4 years. To improve demand response performance, it’s suggested to install air curtains and another form of infiltration barrier, such as a rollup door, for the passageways. Further modifications to increase efficiency of the refrigeration unit are also analyzed. A larger condenser can maintain the minimum saturated condensing temperature (SCT) for more hours of the day. Lowering the SCT reduces the compressor lift, which results in an overall increase in refrigeration system capacity and energy efficiency. Another way of saving energy in refrigerated warehouses is eliminating the use of under-floor resistance heaters. A more energy efficient alternative to resistance heaters is to utilize the heat that is being rejected from the condenser through a heat exchanger. These energy efficiency measures improve efficiency either by reducing the required electric energy input for the refrigeration system, by helping to curtail the refrigeration load on the system, or by reducing both the load and required energy input.

Low Global Warming Potential Refrigerants for Commercial Refrigeration Systems

Energy Technology Data Exchange (ETDEWEB)

Fricke, Brian A. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Sharma, Vishaldeep [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Abdelaziz, Omar [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

2017-06-01

Supermarket refrigeration systems account for approximately 50% of supermarket energy use, placing this class of equipment among the highest energy consumers in the commercial building domain. In addition, the commonly used refrigeration system in supermarket applications is the multiplex direct expansion (DX) system, which is prone to refrigerant leaks due to its long lengths of refrigerant piping. This leakage reduces the efficiency of the system and increases the impact of the system on the environment. The high Global Warming Potential (GWP) of the hydrofluorocarbon (HFC) refrigerants commonly used in these systems, coupled with the large refrigerant charge and the high refrigerant leakage rates leads to significant direct emissions of greenhouse gases into the atmosphere. Environmental concerns are driving regulations for the heating, ventilating, air-conditioning and refrigeration (HVAC&R) industry towards lower GWP alternatives to HFC refrigerants. Existing lower GWP refrigerant alternatives include hydrocarbons, such as propane (R-290) and isobutane (R-600a), as well as carbon dioxide (R-744), ammonia (R-717), and R-32. In addition, new lower GWP refrigerant alternatives are currently being developed by refrigerant manufacturers, including hydrofluoro-olefin (HFO) and unsaturated hydrochlorofluorocarbon (HCFO) refrigerants. The selection of an appropriate refrigerant for a given refrigeration application should be based on several factors, including the GWP of the refrigerant, the energy consumption of the refrigeration system over its operating lifetime, and leakage of refrigerant over the system lifetime. For example, focusing on energy efficiency alone may overlook the significant environmental impact of refrigerant leakage; while focusing on GWP alone might result in lower efficiency systems that result in higher indirect impact over the equipment lifetime. Thus, the objective of this Collaborative Research and Development Agreement (CRADA) between

Method and refrigerants for replacing existing refrigerants in centrifugal compressors

International Nuclear Information System (INIS)

Kopko, W.L.

1991-01-01

This patent describes a method for replacing an existing refrigerant in a centrifugal compressor. It comprises selecting a desired impeller Mach number for the centrifugal compressor; selecting a base refrigerant constituent; combining at least one additive refrigerant constituent with the base refrigerant constituent to form a replacement refrigerant having at least one physical or chemical property different from the existing refrigerant and substantially providing the desired impeller Mach number in the centrifugal compressor; and replacing the existing refrigerant with the replacement refrigerant

Sorption mechanisms and sorption models

International Nuclear Information System (INIS)

Fedoroff, M.; Lefevre, G.; Duc, M.; Neskovic, C.; Milonjic, S.

2004-01-01

Sorption at the solid-liquid interfaces play a major role in many phenomena and technologies: chemical separations, catalysis, biological processes, transport of toxic and radioactive species in surface and underground waters. The long term safety of radioactive waste repositories is based on artificial and natural barriers, intended to sorb radionuclides after the moment when the storage matrixes and containers will be corroded. Predictions on the efficiency of sorption for more than 10 6 years have to be done in order to demonstrate the safety of such depositories, what is a goal never encountered in the history of sciences and technology. For all these purposes, and, especially for the long term prediction, acquiring of sorption data constitutes only a first step of studies. Modeling based on a very good knowledge of sorption mechanisms is needed. In this review, we shall examine the main approaches and models used to quantify sorption processes, including results taken from the literature and from our own studies. We shall compare sorption models and examine their adequacy with sorption mechanisms. The cited references are only a few examples of the numerous articles published in that field. (orig.)

Stability of sodium bicarbonate injection 8.4% in syringes over a six-week period in refrigerated temperature.

Science.gov (United States)

Seki, Jack T; Wang, Tian Q; Yip, Paul M; Mazzulli, Tony; Minden, Mark D

2018-04-01

Background Dysfunctional central venous catheter prohibits the administration of potential life-saving chemotherapy and the delivery of essential supportive care needs to patients. Sodium bicarbonate injection has been shown to impede against fibrin clot formation and prolong prothrombin time and thrombin clotting time. Sodium bicarbonate injection has been tried as a second-line agent with good results in a small number of patients (internal data not published) when alteplase failed. We assessed whether the pre-filled sodium bicarbonate injection in 5 mL syringes would not only preserve sterility and retain its pH and concentration but also amount to the potential cost savings for future use when stored in a refrigerated environment. Methodology Twelve pre-filled 5 mL syringes were prepared aseptically, of which four each were tested for pH, sodium bicarbonate injection concentration and sterility when stored in refrigerated temperature over a six-week period. A standard pH meter, enzymatic carbon dioxide analyzer, and a 14-day incubation for microbial detection were employed for this study. Results Sodium bicarbonate concentration measured in the form of carbon dioxide ranged from 923 mmol/L or (1846 mosol/L) to 1006 mmol/L or (2012 mosmol/L), and pH ranged from (7.88 to 8.05) were reported over the duration of the study period. The 14-day incubation period resulted in no microbial growth. Conclusion Our study results have indicated that the pH and sodium bicarbonate injection concentration values were stable and within range, comparable to those reported by the manufacturer within the study period. The contents of the subdivided sodium bicarbonate injection 5 mL syringes retained sterility over a 14-day incubation period.

Performance of an auto refrigerant cascade refrigerator operating in gas refrigerant supply (GRS) mode with nitrogen-hydrocarbon and argon-hydrocarbon refrigerants

Science.gov (United States)

Gurudath Nayak, H.; Venkatarathnam, G.

2009-07-01

There is a worldwide interest in the development of auto refrigerant cascade (ARC) refrigerators operating with refrigerant mixtures. Both flammable and non-flammable refrigerant mixtures can be used in these systems. The performance of an ARC system with optimum nitrogen-hydrocarbon and argon-hydrocarbon mixtures between 90 and 160 K is presented in this paper.

Refrigeration Playbook: Natural Refrigerants; Selecting and Designing Energy-Efficient Commercial Refrigeration Systems That Use Low Global Warming Potential Refrigerants

Energy Technology Data Exchange (ETDEWEB)

Nelson, Caleb [CTA Architects Engineers, Boise, ID (United States); Reis, Chuck [CTA Architects Engineers, Boise, ID (United States); Nelson, Eric [CTA Architects Engineers, Boise, ID (United States); Armer, James [CTA Architects Engineers, Boise, ID (United States); Arthur, Rob [CTA Architects Engineers, Boise, ID (United States); Heath, Richard [CTA Architects Engineers, Boise, ID (United States); Rono, James [CTA Architects Engineers, Boise, ID (United States); Hirsch, Adam [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Doebber, Ian [National Renewable Energy Laboratory (NREL), Golden, CO (United States)

2015-03-01

This report provides guidance for selecting and designing energy efficient commercial refrigeration systems using low global warming potential refrigerants. Refrigeration systems are generally the largest energy end use in a supermarket type building, often accounting for more than half of a building's energy consumption.

Shuttle Kit Freezer Refrigeration Unit Conceptual Design

Science.gov (United States)

Copeland, R. J.

1975-01-01

The refrigerated food/medical sample storage compartment as a kit to the space shuttle orbiter is examined. To maintain the -10 F in the freezer kit, an active refrigeration unit is required, and an air cooled Stirling Cycle refrigerator was selected. The freezer kit contains two subsystems, the refrigeration unit, and the storage volume. The freezer must provide two basic capabilities in one unit. One requirement is to store 215 lbs of food which is consumed in a 30-day period by 7 people. The other requirement is to store 128.3 lbs of medical samples consisting of both urine and feces. The unit can be mounted on the lower deck of the shuttle cabin, and will occupy four standard payload module compartments on the forward bulkhead. The freezer contains four storage compartments.

Load forecasting for supermarket refrigeration

DEFF Research Database (Denmark)

Bacher, Peder; Madsen, Henrik; Aalborg Nielsen, Henrik

This report presents a study of models for forecasting the load for supermarket refrigeration. The data used for building the forecasting models consists of load measurements, local climate measurements and weather forecasts. The load measurements are from a supermarket located in a village...... in Denmark. The load for refrigeration is the sum of all cabinets in the supermarket, both low and medium temperature cabinets, and spans a period of one year. As input to the forecasting models the ambient temperature observed near the supermarket together with weather forecasts are used. Every hour...

The disappearance of HCFC 22 and the search for the ideal refrigerant; La disparition du HCFC-22 et le recherche du refrigerant ideal

Energy Technology Data Exchange (ETDEWEB)

Dumas, C. [Ville de Montreal, PQ (Canada). Direction des Immeubles Gestion de l' Energie et du Genie Climatique

2003-03-01

The City of Montreal, Quebec is searching for the optimum refrigerant, and has determined that ammonia, carbon dioxide, hydrocarbons and refrigerant-mixes in the 400 series are to be considered for general refrigeration and in skating rinks in the next years. The refrigerants of the 400 series contribute to the greenhouse effect and it is not possible to utilize them in sunk type systems. The City of Montreal has 12 per cent of ice surfaces in Quebec. The Montreal Protocol, a United Nations document calls for the gradual elimination of the refrigerant monochlorodifluoromethane (HCFC 22) starting in 2004 and that none will be made after 2020 in order to protect the ozone layer. In this document, the author discussed the following topics: (1) supply problems, regulations, international index used to compare refrigeration systems, (2) the origin of refrigerants available on the market and why the chemical industry is incapable of producing the miracle refrigerant, and (3) a proposal for an action plan for the control and the reduction of HCFC 22 leaks, the replacement of entire refrigeration systems and the preparation for the period following the availability of HCFC 22. The author offered twelve conclusions. 10 refs., 9 figs.

Sorption of organic gases in a furnished room

Energy Technology Data Exchange (ETDEWEB)

Singer, Brett C.; Revzan, Kenneth L.; Hotchi, Toshifumi; Hodgson, Alfred T.; Brown, Nancy J.

2003-11-30

We present experimental data and semi-empirical models describing the sorption of organic gases in a simulated indoor residential environment. Two replicate experiments were conducted with 20 volatile organic compounds (VOCs) in a 50-m{sup 3} room finished with painted wallboard, carpet and cushion, draperies and furnishings. The VOCs span a wide volatility range and include ten Hazardous Air Pollutants. VOCs were introduced to the static chamber as a pulse and their gas-phase concentrations were measured during a net adsorption period and a subsequent net desorption period. Three sorption models were fit to the measured concentrations for each compound to determine the simplest formulation needed to adequately describe the observed behavior. Sorption parameter values were determined by fitting the models to adsorption period data then checked by comparing measured and predicted behavior during desorption. The adequacy of each model was evaluated using a goodness of fit parameter calculated for each period. Results indicate that sorption usually does not greatly affect indoor concentrations of methyl-tert-butyl ether, 2-butanone, isoprene and benzene. In contrast, sorption appears to be a relevant indoor process for many of the VOCs studied, including C{sub 8}-C{sub 10} aromatic hydrocarbons (HC), terpenes, and pyridine. These compounds sorbed at rates close to typical residential air change rates and exhibited substantial sorptive partitioning at equilibrium. Polycyclic aromatic HCs, aromatic alcohols, ethenylpyridine and nicotine initially adsorbed to surfaces at rates of 1.5 to >6 h{sup -1} and partitioned 95 to >99% in the sorbed phase at equilibrium.

ARTI refrigerant database

Energy Technology Data Exchange (ETDEWEB)

Calm, J.M.

1998-03-15

The Refrigerant Database is an information system on alternative refrigerants, associated lubricants, and their use in air conditioning and refrigeration. It consolidates and facilitates access to thermophysical properties, compatibility, environmental, safety, application and other information. It provides corresponding information on older refrigerants, to assist manufacturers and those using alternative refrigerants, to make comparisons and determine differences. The underlying purpose is to accelerate phase out of chemical compounds of environmental concern. The database provides bibliographic citations and abstracts for publications that may be useful in research and design of air conditioning and refrigeration equipment. It also references documents addressing compatibility of refrigerants and lubricants with other materials.

Thermoacoustic refrigeration

Science.gov (United States)

Garrett, Steven L.; Hofler, Thomas J.

1991-12-01

A new refrigerator which uses resonant high amplitude sound in inert gases to pump heat is described and demonstrated. The phasing of the thermoacoustic cycle is provided by thermal conduction. This 'natural' phasing allows the entire refrigerator to operate with only one moving part (the loudspeaker diaphragm). The thermoacoustic refrigerator has no sliding seals, requires no lubrication, uses only low-tolerance machine parts, and contains no expensive components. Because the compressor moving mass is typically small and the oscillation frequency is high, the small amount of vibration is very easily isolated. This low vibration and lack of sliding seals makes thermoacoustic refrigeration an excellent candidate for food refrigeration and commercial/residential air conditioning applications. The design, fabrication, and performance of the first practical, autonomous thermoacoustic refrigerator, which will be flown on the Space Shuttle (STS-42), are described, and designs for terrestrial applications are presented.

ARTI refrigerant database

Energy Technology Data Exchange (ETDEWEB)

Calm, J.M.

1997-02-01

The Refrigerant Database is an information system on alternative refrigerants, associated lubricants, and their use in air conditioning and refrigeration. It consolidates and facilitates access to property, compatibility, environmental, safety, application and other information. It provides corresponding information on older refrigerants, to assist manufacturers and those using alterative refrigerants, to make comparisons and determine differences. The underlying purpose is to accelerate phase out of chemical compounds of environmental concern. The database provides bibliographic citations and abstracts for publications that may be useful in research and design of air-conditioning and refrigeration equipment. The complete documents are not included, though some may be added at a later date. The database identifies sources of specific information on various refrigerants. It addresses lubricants including alkylbenzene, polyalkylene glycol, polyolester, and other synthetics as well as mineral oils. It also references documents addressing compatibility of refrigerants and lubricants with metals, plastics, elastomers, motor insulation, and other materials used in refrigerant circuits. Incomplete citations or abstracts are provided for some documents. They are included to accelerate availability of the information and will be completed or replaced in future updates.

ARTI refrigerant database

Energy Technology Data Exchange (ETDEWEB)

Calm, J.M. [Calm (James M.), Great Falls, VA (United States)

1999-01-01

The Refrigerant Database is an information system on alternative refrigerants, associated lubricants, and their use in air conditioning and refrigeration. It consolidates and facilities access to property, compatibility, environmental, safety, application and other information. It provides corresponding information on older refrigerants, to assist manufacturers and those using alternative refrigerants, to make comparisons and determine differences. The underlying purpose is to accelerate phase out of chemical compounds of environmental concern.

ARTI refrigerant database

Energy Technology Data Exchange (ETDEWEB)

Calm, J.M.

1996-07-01

The Refrigerant Database is an information system on alternative refrigerants, associated lubricants, and their use in air conditioning and refrigeration. It consolidates and facilitates access to property, compatibility, environmental, safety, application and other information. It provides corresponding information on older refrigerants, to assist manufacturers and those using alternative refrigerants, to make comparisons and determine differences. The underlying purpose is to accelerate phase out of chemical compounds of environmental concern.

ARTI refrigerant database

Energy Technology Data Exchange (ETDEWEB)

Calm, J.M.

1996-11-15

The Refrigerant Database is an information system on alternative refrigerants, associated lubricants, and their use in air conditioning and refrigeration. It consolidates and facilitates access to property, compatibility, environmental, safety, application and other information. It provides corresponding information on older refrigerants, to assist manufacturers and those using alternative refrigerants, to make comparisons and determine differences. The underlying purpose is to accelerate phase out of chemical compounds of environmental concern.

Thermodynamic analysis of a thermally operated cascade sorption heat pump for continuous cold generation

Energy Technology Data Exchange (ETDEWEB)

Muthukumar, P.; Lakshmi, D.V.N. [Department of Mechanical Engineering, Indian Institute of Technology, Guwahati – 781039 (India)

2013-07-01

In this paper, the thermodynamic analysis of a cascade sorption system consists of a two-stage metal hydride heat pump as topping cycle and a single-stage lithium bromide water system as bottom cycle is presented. The effects of various operating temperatures such as driving heat, heat release and refrigeration temperatures, and design parameters such as ratio of metal hydride mass to reactor mass and sensible heat exchange factor on the combined coefficient of performance (COP) of the cascade cycle, and specific cooling power (SCP) and total cold output of the metal hydride heat pump cycle are presented. It is observed that the combined COP is found to increase with heat release and refrigeration temperatures and however, decreases with driving heat temperature. Increase of sensible heat exchange factor improves the system performances significantly. Reduction in mass ratio from 0.5 to 0.1 improves the combined COP of the cascade system by about 10 %. The maximum predicted combined COP of the system is about 1.66 at the driving heat, heat release and refrigeration temperatures of 270 deg C, 125 deg C and 12deg C, respectively.

POWER EFFICIENCY OPPORTUNITIES FOR INDUSTRIAL REFRIGERATION SYSTEM OF FOOD PROCESSING ENTERPRISE

Directory of Open Access Journals (Sweden)

O. Ostapenko

2016-12-01

Full Text Available Rising prices on power supply are forcing business owners to search the ways of operating costs reducing. Refrigeration system in the food industry is a major source of power consumption. The utilization of cold accumulation systems allows reducing of refrigeration unit power consumption. In this paper the refrigeration system with a system of cold accumulation and dry cooling tower is considered. The possibility of power consumption reducing due to the organization of the enterprise refrigeration system operation process in the night period according to electricity multiple tariffs has been analyzed.

ARTI refrigerant database

Energy Technology Data Exchange (ETDEWEB)

Calm, J.M. [Calm (James M.), Great Falls, VA (United States)

1996-04-15

The Refrigerant Database is an information system on alternative refrigerants, associated lubricants, and their use in air conditioning and refrigeration. It consolidates and facilitates access to property, compatibility, environmental, safety, application and other information. It provides corresponding information on older refrigerants, to assist manufacturers and those using alternative refrigerants, to make comparisons and determine differences. The underlying purpose is to accelerate phase out of chemical compounds of environmental concern. The database provides bibliographic citations and abstracts for publications that may be useful in research and design of air-conditioning and refrigeration equipment. The complete documents are not included, though some may be added at a later date. The database identifies sources of specific information on refrigerants. It addresses lubricants including alkylbenzene, polyalkylene glycol, polyolester, and other synthetics as well as mineral oils. It also references documents addressing compatibility of refrigerants and lubricants with metals, plastics, elastomers, motor insulation, and other materials used in refrigerant circuits. Incomplete citations or abstracts are provided for some documents. They are included to accelerate availability of the information and will be completed or replaced in future updates. Citations in this report are divided into the following topics: thermophysical properties; materials compatibility; lubricants and tribology; application data; safety; test and analysis methods; impacts; regulatory actions; substitute refrigerants; identification; absorption and adsorption; research programs; and miscellaneous documents. Information is also presented on ordering instructions for the computerized version.

Hybrid control of the distributed refrigeration system

DEFF Research Database (Denmark)

Chen, L.; Wisniewski, R.

2010-01-01

consumption. The paper focuses on synchronization dynamics of the refrigeration system modeled as a piecewise-affine switched system. System behaviors are analyzed using chaos theory. The synchronization phenomenon is interpreted as a stable low-period orbit; if the system has a high-order periodic orbit...

ARTI refrigerant database

Energy Technology Data Exchange (ETDEWEB)

Calm, J.M. [Calm (James M.), Great Falls, VA (United States)

1998-08-01

The Refrigerant Database is an information system on alternative refrigerants, associated lubricants, and their use in air conditioning and refrigeration. It consolidates and facilitates access to property, compatibility, environmental, safety, application and other information. It provides corresponding information on older refrigerants, to assist manufactures and those using alternative refrigerants, to make comparisons and determine differences. The underlying purpose is to accelerate phase out of chemical compounds of environmental concern. The database provides bibliographic citations and abstracts for publications that may be useful in research and design of air-conditioning and refrigeration equipment. The complete documents are not included, though some may be added at a later date. The database identifies sources of specific information on many refrigerants including propane, ammonia, water, carbon dioxide, propylene, ethers, and others as well as azeotropic and zeotropic blends of these fluids. It addresses lubricants including alkylbenzene, polyalkylene glycol, polyolester, and other synthetics as well as mineral oils. It also references documents addressing compatibility of refrigerants and lubricants with metals, plastics, elastomers, motor insulation, and other materials used in refrigerant circuits. Incomplete citations or abstracts are provided for some documents. They are included to accelerate availability of the information and will be completed or replaced in future updates.

Effect of periodic wetting and drying on selective sorption of 137Cs by mixtures of soil and organomineral sorbent

Science.gov (United States)

Popov, V. E.; Maslova, K. M.; Stepina, I. A.

2014-05-01

The incubation of sandy soddy-podzolic soil with a three-component organomineral sorbent (OMS) on the basis of sapropel, neutralized hydrolysis lignin, and clay-salt slime under alternating wetting-drying (W-D) conditions for two years has increased the selective sorption of 137Cs by 2.5-5 times. The addition of 5% OMS increases the effect of periodic W-D cycles on the selective sorption of 137Cs compared to the addition of 10% OMS. The relationship between the 137Cs interception potential and the number of W-D cycles has been predicted on the basis of the additivity rule and under the assumption that this potential linearly depends on the number of W-D cycles. The predicted values of the 137Cs interception potential almost coincide with the experimental data for the mixtures of sandy soddy-podzolic soil with 10% OMS and are lower than the experimental values by 60% for the mixtures of soil with 10% OMS.

SBIR Grant:No-Vibration Agile Cryogenic Optical Refrigerator

Energy Technology Data Exchange (ETDEWEB)

Epstein, Richard

2013-04-09

Optical refrigeration is currently the only all-solid-state cryocooling technology that has been demonstrated. Optical cryocoolers are devices that use laser light to cool small crystal or glass cooling elements. The cooling element absorbs the laser light and reradiates it at higher energy, an example of anti-Stokes fluorescence. The dif-ference between the energy of the outgoing and incoming light comes from the thermal energy of the cooling element, which in turn becomes colder. Entitled No-Vibration Agile Cryocoolers using Optical Refrigeration, this Phase I proposal directly addressed the continued development of the optical refrigerator components necessary to transition this scientific breakthrough into National Nu-clear Security Administration (NNSA) sensor applications in line with the objectives of topic 50b. ThermoDynamic Films LLC (TDF), in collaboration with the University of New Mexico (UNM), cooled an optical-refrigerator cooling element comprised of an ytterbium-doped yttrium lithium fluoride (Yb:YLF) crystal from room tempera-ture to 123 K with about 2% efficiency. This is the world record in optical refrigera-tion and an important step toward revolutionizing cryogenic systems for sensor ap-plications. During this period, they also designed and analyzed the crucial elements of a prototype optical refrigerator including the thermal link that connects the cool-ing element with the load.

When are solar refrigerators less costly than on-grid refrigerators: A simulation modeling study.

Science.gov (United States)

Haidari, Leila A; Brown, Shawn T; Wedlock, Patrick; Connor, Diana L; Spiker, Marie; Lee, Bruce Y

2017-04-19

Gavi recommends solar refrigerators for vaccine storage in areas with less than eight hours of electricity per day, and WHO guidelines are more conservative. The question remains: Can solar refrigerators provide value where electrical outages are less frequent? Using a HERMES-generated computational model of the Mozambique routine immunization supply chain, we simulated the use of solar versus electric mains-powered refrigerators (hereafter referred to as "electric refrigerators") at different locations in the supply chain under various circumstances. At their current price premium, the annual cost of each solar refrigerator is 132% more than each electric refrigerator at the district level and 241% more at health facilities. Solar refrigerators provided savings over electric refrigerators when one-day electrical outages occurred more than five times per year at either the district level or the health facilities, even when the electric refrigerator holdover time exceeded the duration of the outage. Two-day outages occurring more than three times per year at the district level or more than twice per year at the health facilities also caused solar refrigerators to be cost saving. Lowering the annual cost of a solar refrigerator to 75% more than an electric refrigerator allowed solar refrigerators to be cost saving at either level when one-day outages occurred more than once per year, or when two-day outages occurred more than once per year at the district level or even once per year at the health facilities. Our study supports WHO and Gavi guidelines. In fact, solar refrigerators may provide savings in total cost per dose administered over electrical refrigerators when electrical outages are less frequent. Our study identified the frequency and duration at which electrical outages need to occur for solar refrigerators to provide savings in total cost per dose administered over electric refrigerators at different solar refrigerator prices. Copyright © 2017. Published

Portable refrigerant charge meter and method for determining the actual refrigerant charge in HVAC systems

Science.gov (United States)

Gao, Zhiming; Abdelaziz, Omar; LaClair, Tim L.

2017-08-08

A refrigerant charge meter and a method for determining the actual refrigerant charge in HVAC systems are described. The meter includes means for determining an optimum refrigerant charge from system subcooling and system component parameters. The meter also includes means for determining the ratio of the actual refrigerant charge to the optimum refrigerant charge. Finally, the meter includes means for determining the actual refrigerant charge from the optimum refrigerant charge and the ratio of the actual refrigerant charge to the optimum refrigerant charge.

Investigations on materials for small Stirling refrigerators in long-term operation

International Nuclear Information System (INIS)

Engelland, W.; Kose, V.

1990-04-01

Work is being carried out world-wide on the development of refrigerators with low power requirements for the cooling of high-temperature superconductors and other cryoelectronic components. Due to its good efficiency factor, the well-known Stirling principle is particularly suitable for this purpose, but the increasing contamination of the working gases needed for the process which is caused by outgassing and the permeability to gas of the epoxide resins and other materials generally used makes it prone to interference over long periods of operation. For the first time, DURAN glass has been taken as a regenerator material and tested with successful results over a long period of operation in a small Stirling refrigerator designed and constructed for this purpose. A commercial double-membrane compressor which was also to be tested in long-term operation was converted into a dynamic pressure source and used as a refrigerator component. With this refrigerator, it was possible to maintain a temperature of 34 K over a continous period of operation of 77 days. Parallel to this, mass spectrometric permeation measurements were carried out on a compressor membrane made of VITON in which the water vapour of the atmosphere dominated. (orig.) [de

Application of Cascade Refrigeration System with Mixing Refrigerant in Cold Air Cutting

Science.gov (United States)

Yang, Y.; Tong, M. W.; Yang, G.; Wang, X. P.

In the mechanical cutting process, the replacement of traditional cutting solution with cold air can avoid the pollution of environment. In order to high efficient the refrigerating device and flexible adjust the temperature of cold air, it is necessary to use cascade refrigeration system to supply cool quantity for the compressed air. The introduction of a two-component non-azeotropic mixing refrigerant into the cryogenic part of the cascade system, can effectively solve the problems of the system working at too high pressure and the volume expanding of refrigerant in case of the cascade refrigeration sets closed down. However, the filling ratio of mixing refrigerants impact on the relationships among the closing down pressure, refrigerating output and refrigerating efficiency. On the basis of computing and experiment, the optimal mixing ratio of refrigerant R22/R13 and a low temperature of -60° were obtained in this study. A cold air injecting device possessing high efficiency in energy saving has also been designed and manufactured. The cold air, generated from this cascade system and employed in a cutting process, takes good comprehensive effects on machining and cutting.

When are solar refrigerators less costly than on-grid refrigerators: A simulation modeling study☆

Science.gov (United States)

Haidari, Leila A.; Brown, Shawn T.; Wedlock, Patrick; Connor, Diana L.; Spiker, Marie; Lee, Bruce Y.

2017-01-01

Background Gavi recommends solar refrigerators for vaccine storage in areas with less than eight hours of electricity per day, and WHO guidelines are more conservative. The question remains: Can solar refrigerators provide value where electrical outages are less frequent? Methods Using a HERMES-generated computational model of the Mozambique routine immunization supply chain, we simulated the use of solar versus electric mains-powered refrigerators (hereafter referred to as “electric refrigerators”) at different locations in the supply chain under various circumstances. Results At their current price premium, the annual cost of each solar refrigerator is 132% more than each electric refrigerator at the district level and 241% more at health facilities. Solar refrigerators provided savings over electric refrigerators when one-day electrical outages occurred more than five times per year at either the district level or the health facilities, even when the electric refrigerator holdover time exceeded the duration of the outage. Two-day outages occurring more than three times per year at the district level or more than twice per year at the health facilities also caused solar refrigerators to be cost saving. Lowering the annual cost of a solar refrigerator to 75% more than an electric refrigerator allowed solar refrigerators to be cost saving at either level when one-day outages occurred more than once per year, or when two-day outages occurred more than once per year at the district level or even once per year at the health facilities. Conclusion Our study supports WHO and Gavi guidelines. In fact, solar refrigerators may provide savings in total cost per dose administered over electrical refrigerators when electrical outages are less frequent. Our study identified the frequency and duration at which electrical outages need to occur for solar refrigerators to provide savings in total cost per dose administered over electric refrigerators at different solar

Functional Dependence of Thermodynamic and Thermokinetic Parameters of Refrigerants Used in Mine Air Refrigerators. Part 1 - Refrigerant R407C

Science.gov (United States)

Nowak, Bernard; Życzkowski, Piotr; Łuczak, Rafał

2017-03-01

The authors of this article dealt with the issue of modeling the thermodynamic and thermokinetic properties (parameters) of refrigerants. The knowledge of these parameters is essential to design refrigeration equipment, to perform their energy efficiency analysis, or to compare the efficiency of air refrigerators using different refrigerants. One of the refrigerants used in mine air compression refrigerators is R407C. For this refrigerant, 23 dependencies were developed, determining its thermodynamic and thermokinetic parameters in the states of saturated liquid, dry saturated vapour, superheated vapor, subcooled liquid, and in the two-phase region. The created formulas have been presented in Tables 2, 5, 8, 10 and 12, respectively. It should be noted that the scope of application of these formulas is wider than the range of changes of that refrigerant during the normal operation of mine refrigeration equipment. The article ends with the statistical verification of the developed dependencies. For this purpose, for each model correlation coefficients and coefficients of determination were calculated, as well as absolute and relative deviations between the given values from the program REFPROP 7 (Lemmon et al., 2002) and the calculated ones. The results of these calculations have been contained in Tables 14 and 15.

Review of magnetic refrigeration system as alternative to conventional refrigeration system

Science.gov (United States)

Mezaal, N. A.; Osintsev, K. V.; Zhirgalova, T. B.

2017-10-01

The refrigeration system is one of the most important systems in industry. Developers are constantly seeking for how to avoid the damage to the environment. Magnetic refrigeration is an emerging, environment-friendly technology based on a magnetic solid that acts as a refrigerant by magneto-caloric effect (MCE). In the case of ferromagnetic materials, MCE warms as the magnetic moments of the atom are aligned by the application of a magnetic field. There are two types of magnetic phase changes that may occur at the Curie point: first order magnetic transition (FOMT) and second order magnetic transition (SOMT). The reference cycle for magnetic refrigeration is AMR (Active Magnetic Regenerative cycle), where the magnetic material matrix works both as a refrigerating medium and as a heat regenerating medium, while the fluid flowing in the porous matrix works as a heat transfer medium. Regeneration can be accomplished by blowing a heat transfer fluid in a reciprocating fashion through the regenerator made of magnetocaloric material that is alternately magnetized and demagnetized. Many magnetic refrigeration prototypes with different designs and software models have been built in different parts of the world. In this paper, the authors try to shed light on the magnetic refrigeration and show its effectiveness compared with conventional refrigeration methods.

Brownian micro-engines and refrigerators in a spatially periodic temperature field: Heat flow and performances

International Nuclear Information System (INIS)

Ai Baoquan; Wang Liqiu; Liu Lianggang

2006-01-01

We study the thermodynamic features of a thermal motor driven by temperature differences, which consists of a Brownian particle moving in a sawtooth potential with an external load. The motor can work as a heat engine or a refrigerator under different conditions. The heat flow driven by both potential and kinetic energy is considered. The former is reversible when the engine works quasistatically and the latter is always irreversible. The efficiency of the heat engine (Coefficient Of Performance (COP) of a refrigerator) can never approach Carnot efficiency (COP)

Prediction of metal sorption in soils

International Nuclear Information System (INIS)

Westrich, Henry R.; Anderson, Harold L. Jr.; Arthur, Sara E.; Brady, Patrick V.; Cygan, Randall T.; Liang, Jianjie; Zhang, Pengchu; Yee, N.

2000-01-01

complexes will be affected by substrate composition. Molecular modeling of Ba 2+ sorption on goethite and Cs + sorption on kaolinite surfaces were performed using molecular dynamics techniques with improved Lennard-Jones interatomic potentials under periodic boundary conditions. Ba 2+ was observed to have a preference for inner sphere sorption onto goethite, with the (101) and (110) surfaces representing the controlling sorption surfaces for bulk K D measurements. Large-scale simulations of Cs + sorption on kaolinite (1000's of atoms) provide a statistical basis for the theoretical evaluation and prediction of Cs + K D values. Results suggest the formation of a strong inner sphere complex for Cs + on the kaolinite edge surfaces and a weakly bound outer sphere complex on the hydroxyl basal surface

Mathematical model of the sorption phenomenon of methanol in activated coal

Energy Technology Data Exchange (ETDEWEB)

Cortes, Farid B.; Chejne, Farid; Mejia, Juan M.; Londono, Carlos A. [Grupo de Termodinamica Aplicada y Energias Alternativas - Instituto de Energia, Facultad de Minas, Universidad Nacional de Colombia, sede Medellin (Colombia)

2009-05-15

A transient model of a sorption refrigerator using activated carbon/methanol pair is presented. It is a non-uniform pressure model conformed by the mass, energy and momentum balance equations in cylindrical coordinates, for the activated coal bed contained in the adsorber. The results obtained from the simulation were suitably validated by the experimental information obtained from field test data and from data reported in the literature, presenting errors below 1.6% for each cycle step. The model allows to get data of temperature, pressure, density and gas velocity profiles in radial direction, as well as the solid temperature and the quantity of adsorbed methanol in the activated carbon bed in adsorption/evaporation and desorption/condensation steps. (author)

Mathematical model of the sorption phenomenon of methanol in activated coal

International Nuclear Information System (INIS)

Cortes, Farid B.; Chejne, Farid; Mejia, Juan M.; Londono, Carlos A.

2009-01-01

A transient model of a sorption refrigerator using activated carbon/methanol pair is presented. It is a non-uniform pressure model conformed by the mass, energy and momentum balance equations in cylindrical coordinates, for the activated coal bed contained in the adsorber. The results obtained from the simulation were suitably validated by the experimental information obtained from field test data and from data reported in the literature, presenting errors below 1.6% for each cycle step. The model allows to get data of temperature, pressure, density and gas velocity profiles in radial direction, as well as the solid temperature and the quantity of adsorbed methanol in the activated carbon bed in adsorption/evaporation and desorption/condensation steps.

Refrigeration and global warming

International Nuclear Information System (INIS)

Anon.

1997-01-01

Some aspects of global warming in general, and the implications for refrigerants and refrigerator efficiency in particular, are briefly considered in a question and answer format. The concepts of Global Warming Potential (GWP) and Total Equivalent Warming Impact (TEWI) are explained. GWP is an index which allows a simple comparison to be make between the warming effects of different gases on a kg to kg basis relative to carbon. The GWP depends both on the lifetime of a substance in the atmosphere and its infra-red absorption capacity. The overall warming effect of operating a refrigeration system for its entire life is measured by its TEWI. Chloroflourocarbons (CFCs) which have been widely used as refrigerants are powerful greenhouse gases with high GWPs. Because of the bank of CFCs in refrigerating systems, their levels in the atmosphere are still increasing and it will be some time before refrigerant changes will be effective in reducing the warming effects of refrigerant releases. Hydrocarbons, hydroflourocarbons and ammonia all have a part to play as substitute refrigerants. Refrigerator efficiency is very important in terms of reducing CO 2 emissions. (UK)

Research on sprout inhibition effect of refrigerated garlic by irradiation

International Nuclear Information System (INIS)

Zhang Xuan; He Jianzhong; Li Ruijun

2005-01-01

This paper researches the sprout inhibition effect by irradiation on refrigerated garlic. The results shows that, the garlic is still in the period of dormancy within 7 days after taken out from the refrigerated warehouse, and irradiation have a good sprout inhibition effect on it. The irradiation dose is 40-90 Gy, the same as that of the post harvest irradiation treatment on garlic. Refrigerate the Zhongmu Garlic (at -2 degree C-0 degree C) until the middle ten days of February the next year, place it at the room temperature (10 degree C-15 degree C) for 1-7 days after taking it out of the warehouse, then use 60 Co γ-ray to irradiate it until the absorbed dose reaches 40-90 Gy, the sprout inhibition effect can be realized. The test also indicates that the deposited time after taking out of the refrigerated warehouse is crucial to the sprout inhibition effect of refrigerated garlic by irradiation. (authors)

Influence of Oil on Refrigerant Evaporator Performance

Science.gov (United States)

Kim, Jong-Soo; Nagata, Karsuya; Katsuta, Masafumi; Tomosugi, Hiroyuki; Kikuchi, Kouichiro; Horichi, Toshiaki

In vapor compression refrigeration system using oil-lubricated compressors, some amount of oil is always circulated through the system. Oil circulation can have a significant influence on the evaporator performance of automotive air conditioner which is especially required to cool quickly the car interior after a period standing in the sun. An experimental investigation was carried out an electrically heated horizontal tube to measure local heat transfer coefficients for various flow rates and heat fluxes during forced convection boiling of pure refrigerant R12 and refrigerant-oil mixtures (0-11% oil concentration by weight) and the results were compared with oil free performance. Local heat transfer coefficients increased at the region of low vapor quality by the addition of oil. On the other hand, because the oil-rich liquid film was formed on the heat transfer surface, heat transfer coefficients gradually decreased as the vapor quality became higher. Average heat transfer coefficient reached a maximum at about 4% oil concentration and this trend agreed well with the results of Green and Furse. Previous correlations, using the properties of the refrigerant-oil mixture, could not predict satisfactorily the local heat transfer coefficients data. New correlation modified by oil concentration factor was developed for predicting the corresponding heat transfer coefficient for refrigerant-oil mixture convection boiling. The maximum percent deviation between predicted and measured heat transfer coefficient was within ±30%.

Cryogenic forced convection refrigerating system

International Nuclear Information System (INIS)

Klee, D.J.

1988-01-01

This patent describes the method of refrigerating products by contact with a refrigerating gas which comprises introducing product into a refrigeration zone, contacting the product with the refrigerating gas for a sufficient time to refrigerate it to the appropriate extent and removing the refrigerated product. The improvement for producing the refrigeration gas from a liquid cryogen such that essentially all of the liquid cryogen is fully vaporized before contacting the product comprises: (a) introducing the liquid cryogen, selected from the group consisting of liquid air and liquid nitrogen, at elevated pressure into an ejector as the motive fluid to accelerate a portion of a warm refrigerating gas through the ejector while mixing the cryogen and gas to effect complete vaporization of the liquid cryogen and substantial cooling of the portion of the refrigerating gas resulting in a cold discharge gas which is above the liquefaction temperature of the cryogen; (b) introducing the cold discharge gas into a forced circulation pathway of refrigerating gas and producing a cold refrigerating gas which contacts and refrigerates product and is then at least partially recirculated; (c) sensing the temperature of the refrigerating gas in the forced circulation pathway and controlling the introduction of liquid cryogen with regard to the sensed temperature to maintain the temperature of the discharge gas above the liquefacton temperature of the cryogen utilized

Relationship between composition of mixture charged and that in circulation in an auto refrigerant cascade and a J-T refrigerator operating in liquid refrigerant supply mode

Science.gov (United States)

Sreenivas, Bura; Nayak, H. Gurudath; Venkatarathnam, G.

2017-01-01

The composition of the refrigerant mixture in circulation during steady state operation of J-T and allied refrigerators is not the same as that charged due to liquid hold up in the heat exchangers and phase separators, as well as the differential solubility of different refrigerant components in the compressor lubricating oil. The performance of refrigerators/liquefiers operating on mixed refrigerant cycles is dependent on the mixture composition. It is therefore important to charge the right mixture that results in an optimum composition in circulation during steady state operation. The relationship between the charged and circulating composition has been experimentally studied in a J-T refrigerator operating in the liquid refrigerant supply (LRS) mode and an auto refrigerant cascade refrigerator (with a phase separator) operating in the gas refrigerant supply (GRS) mode. The results of the study are presented in this work. The results show that the method presented earlier for J-T refrigerators operating in GRS mode is also applicable in the case of refrigerators studied in this work.

Flammable refrigerants

NARCIS (Netherlands)

Gerwen, R.J.M. van; Verwoerd, M.; Oostendorp, P.A.

1999-01-01

Hydrocarbons are promising alternatives for CFC, HCFC and HFC refrigerants. Due to their flammable nature, safety aspects have to be considered carefully. The world-wide situation concerning acceptability and practical application of flammable refrigerants is becoming more and more complex and

Performance of refrigerating machineries with new refrigerants; Performance des machines frigorifiques avec les nouveaux refrigerants

Energy Technology Data Exchange (ETDEWEB)

Bailly, A; Jurkowski, R [CIAT, 01 - Culoz (France)

1998-12-31

This paper reports on a comparative study of the thermal performances of different refrigerants like R-22, R-134a, R-404A and R-407C when used as possible substitutes for the HCFC22 refrigerant in a given refrigerating machinery equipped with compact high performance plate exchangers. Thermal performances are compared in identical operating conditions. The behaviour of the two-phase exchange coefficient is analyzed with respect to the different parameters. The composition of the mixture after one year of operation has been analyzed too and the influence of oil on the performances is studied. (J.S.)

Performance of refrigerating machineries with new refrigerants; Performance des machines frigorifiques avec les nouveaux refrigerants

Energy Technology Data Exchange (ETDEWEB)

Bailly, A.; Jurkowski, R. [CIAT, 01 - Culoz (France)

1997-12-31

This paper reports on a comparative study of the thermal performances of different refrigerants like R-22, R-134a, R-404A and R-407C when used as possible substitutes for the HCFC22 refrigerant in a given refrigerating machinery equipped with compact high performance plate exchangers. Thermal performances are compared in identical operating conditions. The behaviour of the two-phase exchange coefficient is analyzed with respect to the different parameters. The composition of the mixture after one year of operation has been analyzed too and the influence of oil on the performances is studied. (J.S.)

Behavior of FFC refrigerants in the presence of refrigerant oils. Oelverhalten chlorfreier Kaeltemittel

Energy Technology Data Exchange (ETDEWEB)

Burke, M.; Kruse, H. (Hannover Univ. (Germany, F.R.). Inst. fuer Kaeltetechnik und Angewandte Waermetechnik)

1990-01-01

Looking for substitutes for the ozone-depleting refrigerants R12 and R22, investigations were made of the miscibility of FFC refrigerants (R23 - trifluoromethane CHF{sub 3}, R134a - tetrafluoroethane CH{sub 3}-CHF{sub 2}, and R152a - difluoroethane CH{sub 3}-CHF{sub 2}) with refrigerator oils. First experimental results reveal the refrigerants' behavior when mixed with mineral oils, alkylbenzene, PAG and ester-based oils. Mixtures of above refrigerants, especially R134a/R152a and R23/R152a as binary nonazeotropic mixtures, are considered conceivable substitutes. While addition of R23 reduces the mixture's flammability, addition of R152a improves the solubility of R134a in refrigerant oils. (orig./HW).

Hysteresis and Temperature Dependency of Moisture Sorption – New Measurements

DEFF Research Database (Denmark)

Rode, Carsten; Hansen, Kurt Kielsgaard

2011-01-01

measurements of hysteresis and temperature dependency of the moisture sorption characteristics of three different porous building materials: aerated concrete, cement paste and spruce. Scanning curves are measured for all three materials where periods with adsorption and desorption interrupt each other...... intermittently. For one of the materials, aerated concrete, the sorption curves are determined at three different temperatures....

Refrigerants and environment

Science.gov (United States)

Tsvetkov, O. B.; Laptev, Yu A.

2017-11-01

The refrigeration and air-conditioning industries are important sectors of the economy and represents about 15 % of global electricity consumptions. The chlorofluorocarbons also called CFCs are a class of refrigerants containing the halogens chlorine and/or fluorine on a carbon skeleton. Because of their environmental impact the Montreal Protocol was negotiated in 1987 to limit the production of certain CFCs and hydrochlirofluorocarbons (HCFCs) in developed and developing countries. The halogenated refrigerants are depleting the ozone layer also major contribution to the greenhouse effect. To be acceptable as a refrigerant a fluid must satisfy a variety of thermodynamic criteria and should be environment friendly with zero Ozone Depletion Potential and low Global Warming Potential. The perspective of a future phase down of HFCs is considered in this report taking into account a strategy for the phase out of HCFCs and perspective of choosing of various refrigerant followed by safety issues.

Prediction and analysis of the seasonal performance of tri-generation and CO2 refrigeration systems in supermarkets

International Nuclear Information System (INIS)

Ge, Y.T.; Tassou, S.A.; Suamir, I.N.

2013-01-01

Highlights: ► Integration model of a trigeneration with CO 2 refrigeration systems in supermarket. ► Validation of the developed integration model with site and laboratory measurement. ► Application of the trigeneration system in power generation and space conditioning. ► Performance analysis and comparison of the integrated system in supermarket. - Abstract: A modern supermarket energy control system has a concurrent need for electricity, space heating or cooling, and food refrigeration. The power supply to the supermarket is primarily from the national grid, where losses in efficiency are due to the processes of energy conversion and transmission. Combined heat and power (CHP) offers the potential to locally produce electrical power and heating which could save energy and reduce CO 2 emissions in the long run. During the summer months, as the space heating requirement in a supermarket is relatively small, the energy efficiency of a CHP installation can be improved by using excess thermal energy to drive a sorption refrigeration system to provide space cooling or refrigeration. This process is also known as tri-generation. In recent years, the use of CO 2 as a refrigerant in supermarkets has received considerable attention due to its negligible contribution to direct greenhouse gas emissions and excellent thermophysical and heat transfer properties. Consequently, the application of a tri-generation system in a supermarket with CO 2 refrigeration merits further investigation. In this paper, to evaluate the performance of a tri-generation system in the supermarket, a previously tested 80 kWe microturbine device was applied into an operational supermarket to generate power and provide space heating and cooling through exhaust heat. The performance evaluation and comparison for this tri-generation application is based on the prediction from an integrated model of supermarket energy control, cascade CO 2 refrigeration and tri-generation systems. The results

Prediction of Dangerous Time in Case Hydrocarbon Refrigerant Leaks into Household Refrigerator Cabinet

Science.gov (United States)

Meguro, Takatoshi; Kaji, Nobufuji; Miyake, Kunihiro

Hydrocarbon refrigerators are now on sale in European countries. However, hydrocarbons are flammable. A common claim is that concentration of hydrocarbon in the refrigerator could exceed the lower explosive limit by a sudden leak and then a spark ignites a flame causing overpressure. There is the need of the studies on potential risks originated from the use of flammable refrigerants. Thus, the flow rate of the fresh air into the refrigerator cabinet has been defined experimentally, and the spatial average concentration in the refrigerator cabinet has been analyzed theoretically to predict the dangerous time in excess of the lower explosive limit.

Theoretical study on a novel dual-nozzle ejector enhanced refrigeration cycle for household refrigerator-freezers

International Nuclear Information System (INIS)

Zhou, Mengliu; Wang, Xiao; Yu, Jianlin

2013-01-01

Highlights: • A novel dual-nozzle ejector enhanced refrigeration cycle is proposed. • The novel cycle is evaluated by using the developed mathematical model. • The results show the performances of the novel cycle could be significantly improved. • The novel cycle shows its promise in household refrigerator-freezers applications. - Abstract: In this study, a novel dual-nozzle ejector enhanced refrigeration cycle is presented for dual evaporator household refrigerator-freezers. The proposed ejector equipped with two nozzles can efficiently recover the expansion work from cycle throttling processes and enhance cycle performances. The performances of the novel cycle are evaluated by using the developed mathematical model, and then compared with that of the conventional ejector enhanced refrigeration cycle and basic vapor-compression refrigeration cycle. The simulation results show that for the given operating conditions, the coefficient of performance (COP) of the novel cycle using refrigerant R134a is improved by 22.9–50.8% compared with that of the basic vapor-compression refrigeration cycle, and the COP improvement is 10.5–30.8% larger than that of the conventional ejector enhanced refrigeration cycle. The further simulation results of the novel cycle using refrigerant R600a indicate that the cycle COP and volumetric refrigeration capacity could be significantly improved

Gamma irradiation in the control of pathogenic bacteria in refrigerated ground chicken meat

Directory of Open Access Journals (Sweden)

Spoto Marta Helena Filet

2000-01-01

Full Text Available This work evaluated the effect of gamma radiation on reducting the population of Staphylococcus aureus, Escherichia coli and Salmonella typhimurium in ground chicken breast stored under refrigeration. The experiment included a control and 4 doses of gamma radiation (2.0, 4.0, 6.0 and 8.0 kGy along with 5 periods of storage under refrigeration (1, 7, 14, 21 and 28 days. Samples of ground chicken breast were inoculated with Staphylococcus aureus (ATCC 14458, Escherichia coli (ATCC 11105 and Salmonella typhimurium (ATCC 0626, irradiated at temperatures between 4 and 8°C and stored under refrigeration (5°C for 28 days. The increased radiation dose and period of storage under refrigeration caused a reduction of Staphylococcus aureus, Escherichia coli and Salmonella typhimurium populations in the ground chicken breast. Mean radiation D values determined for Staphylococcus aureus and Escherichia coli were 0.41 and 0.72 kGy, respectively. Gamma irradiation was an effective treatment for chicken meat conservation because the radiation dose of 6.0 kGy kept the ground chicken breast within the microbiological limits established by the Brazilian legislation, for up to 28 days under refrigeration.

Gamma irradiation in the control of pathogenic bacteria in refrigerated ground chicken meat

International Nuclear Information System (INIS)

Spoto, Marta Helena Fillet; Alcarde, Andre Ricardo; Gurgel, Maria Silvia do Amaral; Blumer, Lucimara; Walder, Julio Marcos Melges; Domarco, Rachel Elisabeth; Gallo, Claudio Rosa

2000-01-01

This work evaluated the effect of gamma radiation on reducing the population of Staphylococcus aureus, Escherichia coli nd Salmonella typhimurium in ground chicken breast stored under refrigeration. The experiment included a control and 4 doses of gamma radiation ( 2.0, 4.0, 6.0 and 8.0 kGy) along with 5 periods of storage under refrigeration ( 1, 7 14, 21 and 28 days). Samples of ground chicken breast were inoculated with Staphylococcus aureus (ATCC 14458), Escherichia coli (ATCC 11105) and Salmonella typhimurium (ATCC 0626), irradiated at temperatures between 4 and 8 deg C and stored under refrigeration (5 deg C) for 28 days. The increased radiation dose and period of storage under refrigeration caused a reduction of Staphylococcus aureus, Escherichia coli and Salmonella typhimurium populations in the ground chicken breast. Mean radiation D values determined for Staphylococcus aureus and Escherichia coli were 0.41 and 0.72 kGy, respectively. Gamma irradiation was an effective treatment for chicken meat conservation because the radiation dose of 6.0 kGy kept the ground chicken breast within the microbiological limits established by the Brazilian legislation for up to 28 days under refrigeration. (author)

Developments in magnetocaloric refrigeration

International Nuclear Information System (INIS)

Brueck, Ekkes

2005-01-01

Modern society relies on readily available refrigeration. Magnetic refrigeration has three prominent advantages compared with compressor-based refrigeration. First, there are no harmful gases involved; second, it may be built more compactly as the working material is a solid; and third, magnetic refrigerators generate much less noise. Recently a new class of magnetic refrigerant-materials for room-temperature applications was discovered. These new materials have important advantages over existing magnetic coolants: they exhibit a large magnetocaloric effect (MCE) in conjunction with a magnetic phase-transition of first order. This MCE is larger than that of Gd metal, which is used in the demonstration refrigerators built to explore the potential of this evolving technology. In the present review we compare the different materials considering both scientific aspects and industrial applicability. Because fundamental aspects of MCE are not so widely discussed, we also give some theoretical considerations. (topical review)

Energy performance of supermarket refrigeration and air conditioning integrated systems working with natural refrigerants

International Nuclear Information System (INIS)

Cecchinato, Luca; Corradi, Marco; Minetto, Silvia

2012-01-01

The current trends in commercial refrigeration aim at reducing the synthetic refrigerant charge, either by minimising the internal volume of the circuit or by utilising natural refrigerants, and at energy saving. The energy efficiency of supermarkets can be improved by optimising components design, recovering thermal and refrigerating energy, adopting innovative technology solutions, integrating the HVAC system with medium temperature and low temperature refrigeration plants and, finally, reducing thermal loads on refrigerated cases. This study aims at investigating the performance of different lay-out and technological solutions where only natural refrigerants are used and at finding the potential for improving energy efficiency over the traditional systems in different climates. In the analysis, chillers and heat pumps working with ammonia or propane, medium temperature systems working with ammonia or propane and carbon dioxide as heat transfer fluid or with carbon dioxide as the refrigerant and low temperature systems working with carbon dioxide are considered and benchmarked with a state-of-the-art HFCs based plant. The most efficient investigated solution enables an annual energy saving higher than 15% with respect to the baseline solution for all the considered climates. - Highlights: ► Different natural refrigerants supermarket HVAC and R integrated systems are analysed. ► Some of the proposed solutions offer a significant benefit over the baseline one. ► Up to 18.7% energy saving is achieved in the considered climates. ► The refrigeration unit condensation by the AC chiller offers the poorest results.

Quantum refrigerators and the third law of thermodynamics.

Science.gov (United States)

Levy, Amikam; Alicki, Robert; Kosloff, Ronnie

2012-06-01

The rate of temperature decrease of a cooled quantum bath is studied as its temperature is reduced to absolute zero. The third law of thermodynamics is then quantified dynamically by evaluating the characteristic exponent ζ of the cooling process dT(t)/dt∼-T^{ζ} when approaching absolute zero, T→0. A continuous model of a quantum refrigerator is employed consisting of a working medium composed either by two coupled harmonic oscillators or two coupled two-level systems. The refrigerator is a nonlinear device merging three currents from three heat baths: a cold bath to be cooled, a hot bath as an entropy sink, and a driving bath which is the source of cooling power. A heat-driven refrigerator (absorption refrigerator) is compared to a power-driven refrigerator. When optimized, both cases lead to the same exponent ζ, showing a lack of dependence on the form of the working medium and the characteristics of the drivers. The characteristic exponent is therefore determined by the properties of the cold reservoir and its interaction with the system. Two generic heat bath models are considered: a bath composed of harmonic oscillators and a bath composed of ideal Bose/Fermi gas. The restrictions on the interaction Hamiltonian imposed by the third law are discussed. In the Appendices, the theory of periodically driven open systems and its implication for thermodynamics are outlined.

Sorption of sodium hydroxide by type I collagen and bovine corneas.

Science.gov (United States)

Whikehart, D R; Edwards, W C; Pfister, R R

1991-01-01

There are no quantitative studies on the uptake of alkali into corneal tissues. To study this phenomenon, both type I collagen and bovine corneas were incubated in sodium hydroxide (NaOH) under varying conditions for periods up to 27.5 h. The sorption (absorption or adsorption) of the alkali to protein and tissue was measured as the quantity of NaOH no longer available for titration to neutrality with hydrochloric acid. Sorption was found to be dependent on the concentration of NaOH (0.01-1 N) but independent of the incubation temperature (4-35 degrees C). In whole cornea, sorption of 1 N NaOH began immediately and increased with time up to 6 h. After 6 h, sorption decreased, together with the observed degradation and solubilization of the tissue. Stripping of the corneal endothelium alone or of the endothelium and epithelium increased sorption in a similar manner when compared to whole corneas for periods up to 4 h. These observations are compatible with ionic and nonionic bonding of hydroxide ions to collagen (including that of the cornea) and the subsequent release of hydroxide ions during hydrolysis of the protein itself. Indirect evidence also suggests the inclusion of quantities of unbound hydroxide ions in hydrated gels of glycosaminoglycans. It is proposed that in a chemical burn of the cornea, alkali is both stored in the tissue (by sorption) and reacted with it (by hydrolysis), without any net consumption of alkali taking place.

COP improvement of refrigerator/freezers, air-conditioners, and heat pumps using nonazeotropic refrigerant mixtures

Science.gov (United States)

Westra, Douglas G.

1993-01-01

With the February, 1992 announcement by President Bush to move the deadline for outlawing CFC (chloro-fluoro-carbon) refrigerants from the year 2000 to the year 1996, the refrigeration and air-conditioning industries have been accelerating their efforts to find alternative refrigerants. Many of the alternative refrigerants being evaluated require synthetic lubricants, are less efficient, and have toxicity problems. One option to developing new, alternative refrigerants is to combine existing non-CFC refrigerants to form a nonazeotropic mixture, with the concentration optimized for the given application so that system COP (Coefficient Of Performance) may be maintained or even improved. This paper will discuss the dilemma that industry is facing regarding CFC phase-out and the problems associated with CFC alternatives presently under development. A definition of nonazeotropic mixtures will be provided, and the characteristics and COP benefits of nonazeotropic refrigerant mixtures will be explained using thermodynamic principles. Limitations and disadvantages of nonazeotropic mixtures will be discussed, and example systems using such mixtures will be reviewed.

Fermilab tevatron five refrigerator system tests

International Nuclear Information System (INIS)

Rode, C.; Ferry, R.; Leiniger, M.; Makara, J.; Misek, J.; Mizicko, D.; Richied, D.; Theilacker, J.

1982-01-01

The Fermilab Tevatron refrigeration system is described with the layout illustrated. The compressor control loops, the refrigerator control loops, and magnet control loops (two per refrigerator) are described and each illustrated. The mobile purifier is described. A five refrigerator test is presented, using two compressor buildings, satellite refrigerator concept test and the test current to the writing. The configuration of the five refrigerator test is diagramed

ARTI Refrigerant Database

Energy Technology Data Exchange (ETDEWEB)

Cain, J.M. (Calm (James M.), Great Falls, VA (United States))

1993-04-30

The Refrigerant Database consolidates and facilitates access to information to assist industry in developing equipment using alternative refrigerants. The underlying purpose is to accelerate phase out of chemical compounds of environmental concern. The database provides bibliographic citations and abstracts for publications that may be useful in research and design of air-conditioning and refrigeration equipment. The complete documents are not included. The database identifies sources of specific information on R-32, R-123, R-124, R-125, R-134, R-134a, R-141b, R-142b, R-143a, R-152a, R-245ca, R-290 (propane), R-717 (ammonia), ethers, and others as well as azeotropic and zeotropic blends of these fluids. It addresses lubricants including alkylbenzene, polyalkylene glycol, ester, and other synthetics as well as mineral oils. It also references documents addressing compatibility of refrigerants and lubricants with metals, plastics, elastomers, motor insulation, and other materials used in refrigerant circuits. Incomplete citations or abstracts are provided for some documents to accelerate availability of the information and will be completed or replaced in future updates.

ARTI Refrigerant Database

Energy Technology Data Exchange (ETDEWEB)

Calm, J.M. [Calm (James M.), Great Falls, VA (United States)

1994-05-27

The Refrigerant Database consolidates and facilitates access to information to assist industry in developing equipment using alternative refrigerants. The underlying purpose is to accelerate phase out of chemical compounds of environmental concern.

Magnon-driven quantum dot refrigerators

Energy Technology Data Exchange (ETDEWEB)

Wang, Yuan; Huang, Chuankun; Liao, Tianjun; Chen, Jincan, E-mail: jcchen@xmu.edu.cn

2015-12-18

Highlights: • A three-terminal quantum dot refrigerator is proposed. • The effects of magnetic field, applied voltage, and polarization are considered. • The region that the system can work as a refrigerator is determined. • Two different magnon-driven quantum dot refrigerators are compared. - Abstract: A new model of refrigerator consisting of a spin-splitting quantum dot coupled with two ferromagnetic reservoirs and a ferromagnetic insulator is proposed. The rate equation is used to calculate the occupation probabilities of the quantum dot. The expressions of the electron and magnon currents are obtained. The region that the system can work in as a refrigerator is determined. The cooling power and coefficient of performance (COP) of the refrigerator are derived. The influences of the magnetic field, applied voltage, and polarization of two leads on the performance are discussed. The performances of two different magnon-driven quantum dot refrigerators are compared.

Applicability of ASST-A helium refrigeration system for JLab End Station Refrigerator

Science.gov (United States)

Hasan, N.; Knudsen, P.; Ganni, V.

2017-12-01

The MØLLER experiment at Jefferson Lab (JLab) is a high power (5 kW) liquid hydrogen target scheduled to be operational in the 12 GeV-era. At present, cryogenic loads and targets at three of JLab’s four experimental halls are supported by the End Station Refrigerator (ESR) - a CTI/Helix 1.5 kW 4.5 K refrigerator. It is not capable of supporting the high power target load and a capacity upgrade of the ESR cryogenic system is essential. The ASST-A helium refrigeration system is a 4 kW 4.5 K refrigerator. It was designed and used for the Superconducting Super Collider Lab (SSCL) magnet string test and later obtained by JLab after the cancellation of that project. The modified ASST-A refrigeration system, which will be called ESR-II along with a support flow from JLab’s Central Helium Liquefier (CHL) is considered as an option for the End Station Refrigerator capacity upgrade. The applicability of this system for ESR-II under varying load conditions is investigated. The present paper outlines the findings of this process study.

Dynamics of gas bubble growth in oil-refrigerant mixtures under isothermal decompression

Energy Technology Data Exchange (ETDEWEB)

Dias, Joao Paulo; Barbosa Junior, Jader R.; Prata, Alvaro T. [Federal University of Santa Catarina (UFSC), Florianopolis, SC (Brazil). Dept. of Mechanical Engineering], Emails: jpdias@polo.ufsc.br, jrb@polo.ufsc.br, prata@polo.ufsc.br

2010-07-01

This paper proposes a numerical model to predict the growth of gaseous refrigerant bubbles in oil-refrigerant mixtures with high contents of oil subjected to isothermal decompression. The model considers an Elementary Cell (EC) in which a spherical bubble is surrounded by a concentric and spherical liquid layer containing a limited amount of dissolved liquid refrigerant. The pressure reduction in the EC generates a concentration gradient at the bubble interface and the refrigerant is transported to the bubble by molecular diffusion. After a sufficiently long period of time, the concentration gradient in the liquid layer and the bubble internal pressure reach equilibrium and the bubble stops growing, having attained its stable radius. The equations of momentum and chemical species conservation for the liquid layer, and the mass balance at the bubble interface are solved via a coupled finite difference procedure to determine the bubble internal pressure, the refrigerant radial concentration distribution and the bubble growth rate. Numerical results obtained for a mixture of ISO VG10 ester oil and refrigerant HFC-134a showed that bubble growth dynamics depends on model parameters like the initial bubble radius, initial refrigerant concentration in the liquid layer, decompression rate and EC temperature. Despite its simplicity, the model showed to be a potential tool to predict bubble growth and foaming which may result from important phenomena occurring inside refrigeration compressors such as lubrication of sliding parts and refrigerant degassing from the oil stored in oil sump during compressor start-up. (author)

A study of alternative refrigerants for the refrigeration and air conditioning sector in Mauritius

Science.gov (United States)

Dreepaul, R. K.

2017-11-01

The most frequently used refrigerants in the refrigeration and air conditioning (RAC) sector in Mauritius are currently hydrochlorofluorocarbons (HCFC) and hydrofluorocarbons (HFC). However, because of their strong influence on global warming and the impact of HCFCs on the ozone layer, refrigerants such as ammonia (NH3), carbon dioxide (CO2) and Hydrocarbons (HC), having minimal impact on the environment, are being considered. So far, HCs have only been safely used in domestic refrigeration. Ammonia has been used mainly for industrial refrigeration whereas CO2 is still under study. In this paper, a comparative study of the various feasible alternatives is presented in a survey that was undertaken with major stake holders in the field. The retrofitting possibility of existing equipment was assessed and safety issues associated with each refrigerant were analysed. The major setback of hydrocarbons as a widely accepted refrigerant is its flammability which was considered as a major safety hazard by the majority of respondents in the survey and the main advantages are the improved equipment coefficient of performance (COP) and better TEWI factor. This resulted in a 12 % drop in energy consumption. Despite the excellent thermodynamic properties of ammonia, its use has mainly been confined to industrial refrigeration due to its toxicity. In Mauritius, the performance of ammonia in air conditioning is being evaluated on a pilot basis. The major setback of carbon dioxide as a refrigerant is the high operating pressure which is considered a safety hazard. The high initial investment cost and the lack of qualified maintenance technician is also an issue. The use of CO2 is mainly being considered in the commercial refrigeration sector.

Sorption data bases and mechanistic sorption studies

International Nuclear Information System (INIS)

Bradbury, M.H.

2000-01-01

In common with many other countries with a nuclear programme, the Swiss concept for the disposal of radioactive waste is focused on deep burial in specially constructed repositories in geologically stable host rocks. Under such conditions, the most likely means whereby radionuclides might return to the biosphere involves their transport in slowly moving groundwater. The sorption of radionuclides by solid phases in the engineered barriers within the repository, and in the surrounding geological media, limits their release and retards their movement. Performance assessment studies for disposal concepts are carried out by Nagra, the National Cooperative for the Disposal of Radioactive Waste, in which various release scenarios are examined, and 'doses to man' calculated. The uptake of radionuclides by immobile phases is one of the pillars upon which the safety case rests. Hence, sorption databases are very important data sets for performance assessments. The methodology lying behind the construction of sorption databases, and some aspects of the supporting experimental work, are briefly described in this report. Flexible, long-term, focused research programmes are required to properly understand the radionuclide/rock/groundwater system, and this is an essential pre-requisite for producing robust state-of-the-art sorption databases. (author)

Thermodynamic performance of an auto-cascade ejector refrigeration cycle with mixed refrigerant R32 + R236fa

International Nuclear Information System (INIS)

Tan, Yingying; Wang, Lin; Liang, Kunfeng

2015-01-01

In this paper, an auto-cascade ejector refrigeration cycle (ACERC) is proposed to obtain lower refrigeration temperature based on conventional ejector refrigeration and auto-cascade refrigeration principle. The thermodynamic performance of ACERC is investigated theoretically. The zeotropic refrigerant mixture R32 + R236fa is used as its working fluid. A parametric analysis is conducted to evaluate the effects of some thermodynamic parameters on the cycle performance. The study shows that refrigerant mixture composition, condenser outlet temperature and evaporation pressure have effects on performance of ACERC. The theoretical results also indicate that the ACERC can achieve the lowest refrigeration temperature at the temperature level of −30 °C. The application of zeotropic refrigerant mixture auto-cascade refrigeration in the ejector refrigeration cycle can provide a new way to obtain lower refrigeration temperature utilizing low-grade thermal energy. - Highlights: • An auto-cascade ejector refrigerator with R32 + R236fa mixed refrigerant is proposed. • The cycle can obtain a refrigeration temperature at −30 °C temperature range. • The effects of some thermodynamic parameters on the cycle performance are evaluated

High Efficiency, Low Emission Refrigeration System

Energy Technology Data Exchange (ETDEWEB)

Fricke, Brian A [ORNL; Sharma, Vishaldeep [ORNL

2016-08-01

Supermarket refrigeration systems account for approximately 50% of supermarket energy use, placing this class of equipment among the highest energy consumers in the commercial building domain. In addition, the commonly used refrigeration system in supermarket applications is the multiplex direct expansion (DX) system, which is prone to refrigerant leaks due to its long lengths of refrigerant piping. This leakage reduces the efficiency of the system and increases the impact of the system on the environment. The high Global Warming Potential (GWP) of the hydrofluorocarbon (HFC) refrigerants commonly used in these systems, coupled with the large refrigerant charge and the high refrigerant leakage rates leads to significant direct emissions of greenhouse gases into the atmosphere. Methods for reducing refrigerant leakage and energy consumption are available, but underutilized. Further work needs to be done to reduce costs of advanced system designs to improve market utilization. In addition, refrigeration system retrofits that result in reduced energy consumption are needed since the majority of applications address retrofits rather than new stores. The retrofit market is also of most concern since it involves large-volume refrigerant systems with high leak rates. Finally, alternative refrigerants for new and retrofit applications are needed to reduce emissions and reduce the impact on the environment. The objective of this Collaborative Research and Development Agreement (CRADA) between the Oak Ridge National Laboratory and Hill Phoenix is to develop a supermarket refrigeration system that reduces greenhouse gas emissions and has 25 to 30 percent lower energy consumption than existing systems. The outcomes of this project will include the design of a low emission, high efficiency commercial refrigeration system suitable for use in current U.S. supermarkets. In addition, a prototype low emission, high efficiency supermarket refrigeration system will be produced for

Demand Response Opportunities in Industrial Refrigerated Warehouses in California

Energy Technology Data Exchange (ETDEWEB)

Goli, Sasank; McKane, Aimee; Olsen, Daniel

2011-06-14

Industrial refrigerated warehouses that implemented energy efficiency measures and have centralized control systems can be excellent candidates for Automated Demand Response (Auto-DR) due to equipment synergies, and receptivity of facility managers to strategies that control energy costs without disrupting facility operations. Auto-DR utilizes OpenADR protocol for continuous and open communication signals over internet, allowing facilities to automate their Demand Response (DR). Refrigerated warehouses were selected for research because: They have significant power demand especially during utility peak periods; most processes are not sensitive to short-term (2-4 hours) lower power and DR activities are often not disruptive to facility operations; the number of processes is limited and well understood; and past experience with some DR strategies successful in commercial buildings may apply to refrigerated warehouses. This paper presents an overview of the potential for load sheds and shifts from baseline electricity use in response to DR events, along with physical configurations and operating characteristics of refrigerated warehouses. Analysis of data from two case studies and nine facilities in Pacific Gas and Electric territory, confirmed the DR abilities inherent to refrigerated warehouses but showed significant variation across facilities. Further, while load from California's refrigerated warehouses in 2008 was 360 MW with estimated DR potential of 45-90 MW, actual achieved was much less due to low participation. Efforts to overcome barriers to increased participation may include, improved marketing and recruitment of potential DR sites, better alignment and emphasis on financial benefits of participation, and use of Auto-DR to increase consistency of participation.

10 CFR 431.62 - Definitions concerning commercial refrigerators, freezers and refrigerator-freezers.

Science.gov (United States)

2010-01-01

... functional characteristics that affect energy consumption. Commercial refrigerator, freezer, and refrigerator... formed by the plane of the door, when the equipment is viewed in cross-section; and (2) For equipment...

Sorption data bases and mechanistic sorption studies

Energy Technology Data Exchange (ETDEWEB)

Bradbury, M.H

2000-07-01

In common with many other countries with a nuclear programme, the Swiss concept for the disposal of radioactive waste is focused on deep burial in specially constructed repositories in geologically stable host rocks. Under such conditions, the most likely means whereby radionuclides might return to the biosphere involves their transport in slowly moving groundwater. The sorption of radionuclides by solid phases in the engineered barriers within the repository, and in the surrounding geological media, limits their release and retards their movement. Performance assessment studies for disposal concepts are carried out by Nagra, the National Cooperative for the Disposal of Radioactive Waste, in which various release scenarios are examined, and 'doses to man' calculated. The uptake of radionuclides by immobile phases is one of the pillars upon which the safety case rests. Hence, sorption databases are very important data sets for performance assessments. The methodology lying behind the construction of sorption databases, and some aspects of the supporting experimental work, are briefly described in this report. Flexible, long-term, focused research programmes are required to properly understand the radionuclide/rock/groundwater system, and this is an essential pre-requisite for producing robust state-of-the-art sorption databases. (author)

Evaluation of sorption distribution coefficient of Cs onto granite using sorption data collected in sorption database and sorption model

International Nuclear Information System (INIS)

Nagasaki, S.

2013-01-01

Based on the sorption distribution coefficients (K d ) of Cs onto granite collected from the JAERI Sorption Database (SDB), the parameters for a two-site model without the triple-layer structure were optimized. Comparing the experimentally measured K d values of Cs onto Mizunami granite carried out by JAEA with the K d values predicted by the model, the effect of the ionic strength on the K d values of Cs onto granite was evaluated. It was found that K d values could be determined using the content of biotite in granite at a sodium concentration ([Na]) of 1 x 10 -2 to 5 x 10 -1 mol/dm 3 . It was suggested that in high ionic strength solutions, the sorption of Cs onto other minerals such as microcline should also be taken into account. (author)

Quality Model of Foodstuff in a Refrigerated Display Cabinet

DEFF Research Database (Denmark)

Cai, Junping; Risum, Jørgen; Thybo, Claus

2006-01-01

Commercial refrigerating systems need to be defrosted regularly to maintain a satisfactory performance. When defrosting the evaporator coil, the air temperature inside the display cabinet will increase, and float outside the normal temperature range for a period of time, the question is what...... happens to the food inside during this period, when we look at the quality factor? This paper discusses quality model of foodstuff, different scenarios of defrost scheme are simulated, questions such as how the defrost temperature and duration influence the food temperature, thus the food quality, as well...... as what is the optimal defrost scheme from food quality point of view are answered. This will serve as a prerequisite of designing of optimal control scheme for the commercial refrigeration system, aiming at optimizing a weighed cost function of both food quality and overall energy consumption of system....

Ultimate refrigerating conditions, behavior turning and a thermodynamic analysis for absorption–compression hybrid refrigeration cycle

International Nuclear Information System (INIS)

Zheng Danxing; Meng Xuelin

2012-01-01

Highlights: ► Two novel fundamental concepts of the absorption refrigeration cycle were proposed. ► The interaction mechanism of compressor pressure increasing with other key-parameters was investigated. ► A set of optimal operating condition of hybrid refrigeration cycle was found. ► A simulation and investigation for R134a-DMF hybrid refrigeration cycle was performed. - Abstract: The absorption–compression hybrid refrigeration cycle has been considered as an effective approach to reduce the mechanical work consumption by using low-grade heat, such as solar energy. This work aims at studying the thermodynamic mechanism of the hybrid refrigeration cycle. Two fundamental concepts have been proposed, which are the ultimate refrigerating temperature (or the ultimate temperature lift) and the behavior turning. On the basis of that, the interaction mechanism of compressor pressure increasing with other key-parameters and the impact of compressor pressure increasing on the cycle performance have been investigated. The key-parameters include the concentration difference, the circulation ratio of working fluid, etc. The work points out that the hybrid refrigeration cycle performance varies with the change of compressor outlet pressure and depends on which one achieves dominance in the hybrid refrigeration cycle, the absorption sub-system or the compression sub-system. The behavior turning point during parameters changing corresponds to a maximum value of the heat powered coefficient of performance. In this case, the hybrid refrigeration cycle performance is optimal because the low-grade heat utilization is the most effective. In addition, to validate the theoretical analysis, a solar hybrid refrigeration cycle with R134a–DMF as working pair was simulated. The Peng–Robinson equation of state was adopted to calculate thermophysical properties when the reliability assessment of the prediction models on the available literature data of R134a–DMF system had been

Sorption behavior of neptunium on bentonite -- Effect of calcium ion on the sorption

International Nuclear Information System (INIS)

Kozai, Naofumi; Ohnuki, Toshihiko; Muraoka, Susumu

1995-01-01

The sorption behavior of neptunium on bentonite was studied with batch type sorption and desorption experiments over a pH range of 2 to 8. A series of parallel studies using Na-smectite, Ca-smectite and admixtures of Na-smectite and calcite quantified the capacity of Ca 2+ (which occurs in bentonite as an exchangeable cation of smectite and as a component of calcite) to inhibit the sorption of neptunium. The distribution coefficient (K d ) of neptunium for bentonite was constant from pH 2 to 7, while for pure Na-smectite K d increased below pH 5 due to specific sorption of neptunium on Na-smectite. Specific sorption was defined as occurring when neptunium could be desorbed by a strong acid (1 M HCl) but was stable in the presence of 1 M KCl. It was found that the quantity of neptunium sorbed on Na-smectite was inversely proportional to the concentration of Ca 2+ in solution, an effect most pronounced at pH 2+ limits the specific sorption capacity of Na-smectite for neptunium. Similarly, in the mixture of Na-smectite and calcite, sufficient Ca 2+ was solubilized to depress neptunium sorption. This investigation demonstrates that Ca 2+ contained in bentonite as exchangeable cation and released from calcite reduces the specific sorption of neptunium

Thermoelectric refrigerator having improved temperature stabilization means

International Nuclear Information System (INIS)

Falco, C.M.

1982-01-01

A control system for thermoelectric refrigerators is disclosed. The thermoelectric refrigerator includes at least one thermoelectric element that undergoes a first order change at a predetermined critical temperature. The element functions as a thermoelectric refrigerator element above the critical temperature, but discontinuously ceases to function as a thermoelectric refrigerator element below the critical temperature. One example of such an arrangement includes thermoelectric refrigerator elements which are superconductors. The transition temperature of one of the superconductor elements is selected as the temperature control point of the refrigerator. When the refrigerator attempts to cool below the point, the metals become superconductors losing their ability to perform as a thermoelectric refrigerator. An extremely accurate, first-order control is realized

Environment-friendly refrigeration - Switzerland moves forward

International Nuclear Information System (INIS)

Stohler, F.

2003-01-01

This article presents an interview with Silvan Schaller, president of the Swiss Refrigeration Society SVK and head of a leading Swiss industrial refrigeration company, on the subject of the implementation of new Swiss materials legislation that regulates the use of various refrigerants. In particular, the co-operation between the Society and the regulatory authorities is stressed. The reasons behind the regulations - the protection of the environment and, in particular, the ozone layer - are discussed as are the efforts required by industry to meet them. Future refrigeration technologies and the choice of refrigerants are examined. Measures that will have to be taken by the companies in the refrigeration sector, such as the additional training of personnel and the monitoring of the disposal of wastes, are examined. For the future, the goal of reducing the energy consumption of refrigeration installations is noted

Fault diagnosis and refrigerant leak detection in vapour compression refrigeration systems

Energy Technology Data Exchange (ETDEWEB)

Tassou, S.A.; Grace, I.N. [Brunel University, Uxbridge (United Kingdom). Department of Mechanical Engineering

2005-08-01

The environmental impact of refrigeration systems can be reduced by operation at higher efficiency and reduction of refrigerant leakage. Refrigerant loss contributes both directly and indirectly to global warming through inefficient system operation, increased power consumption and greenhouse gas emissions and higher maintenance costs. Existing sensor-based leak detection methods are limited by the inability to detect gradual leakage and the need for careful sensor location. There is a requirement for a real-time performance monitoring approach to leak detection and fault diagnosis which overcomes these disadvantages. This paper reports on the development of a fault diagnosis and refrigerant leak detection system based on artificial intelligence and real-time performance monitoring. The system has been used successfully to distinguish between faulty and fault free operation, steady-state and transient operation, leakage and over charge conditions. Work currently underway is aimed at testing additional fault conditions and establishing further rules to distinguish between these patterns. (author)

Regulating Power from Supermarket Refrigeration

DEFF Research Database (Denmark)

O'Connell, Niamh; Madsen, Henrik; Pinson, Pierre

2014-01-01

the Danfoss refrigeration test centre. The complexities of modelling demand response are demonstrated through simulation. Simulations are conducted by placing the identified model in a direct-control demand response architecture, with power reference tracking using model predictive control. The energylimited......This paper presents an analysis of the demand response capabilities of a supermarket refrigeration system, with a particular focus on the suitability for participation in the regulating power market. An ARMAX model of a supermarket refrigeration system is identified using experimental data from...... nature of demand response from refrigeration is identified as the key consideration when considering participation in the regulating power market. It is demonstrated that by restricting the operating regions of the supermarket refrigeration system, a simple relationship can be found between the available...

Evaluation of sorption distribution coefficient of Cs onto granite using sorption data collected in sorption database and sorption model

Energy Technology Data Exchange (ETDEWEB)

Nagasaki, S., E-mail: nagasas@mcmaster.ca [McMaster Univ., Hamilton, Ontario (Canada)

2013-07-01

Based on the sorption distribution coefficients (K{sub d}) of Cs onto granite collected from the JAERI Sorption Database (SDB), the parameters for a two-site model without the triple-layer structure were optimized. Comparing the experimentally measured K{sub d} values of Cs onto Mizunami granite carried out by JAEA with the K{sub d} values predicted by the model, the effect of the ionic strength on the K{sub d} values of Cs onto granite was evaluated. It was found that K{sub d} values could be determined using the content of biotite in granite at a sodium concentration ([Na]) of 1 x 10{sup -2} to 5 x 10{sup -1} mol/dm{sup 3} . It was suggested that in high ionic strength solutions, the sorption of Cs onto other minerals such as microcline should also be taken into account. (author)

Transition to New Refrigerants

Science.gov (United States)

Overview page provides information on the refrigerants that motor vehicle air conditioners have used over time, with information on environmental impacts, refrigerant fitting sizes, label colors, and alternatives to ozone-depleting substances.

Radionuclide sorption kinetics and column sorption studies with Columbia River basalts

International Nuclear Information System (INIS)

Barney, G.S.

1983-09-01

The kinetics of radionuclide sorption and desorption reactions in basalt-groundwater systems were evaluated at 60 degrees C using a batch equilibration method. It was found that many sorption reactions on surfaces of fresh (unaltered) basalt from the Umtanum and Cohassett flows are slow. Some reactions require more than 50 days to reach a steady state. Sorption of neptunium and uranium in oxidizing (air saturated) groundwater appears to be controlled by slow reduction of these elements by the basalt surfaces. The resulting lower oxidation states are more strongly sorbed. Technetium and selenium, which are anionic under oxidizing conditions, are not measurably sorbed on fresh basalt surfaces, but are slightly sorbed on the altered surfaces of flow top basalt. Under reducing conditions, where the groundwater contains dilute hydrazine, sorption is faster for neptunium, uranium, technetium, selenium, and lead. Plutonium sorption rates were not affected by the groundwater Eh. It was shown that radium was precipitated rather than sorbed under the conditions of these experiments. Umtanum flow top material sorbed radionuclides much faster than fresh basalt surfaces due to its greater surface area and cation exchange capacity. Desorption rates for plutonium, uranium, neptunium, technetium, and selenium were generally much less than sorption rates (especially for reducing conditions). These radionuclides are irreversibly sorbed on the basalts. 25 refs., 20 figs., 19 tabs

Influence of the nozzle angle on refrigeration performance of a gas wave refrigerator

Science.gov (United States)

Liu, P.; Zhu, Y.; Wang, H.; Zhu, C.; Zou, J.; Wu, J.; Hu, D.

2017-05-01

A gas wave refrigerator (GWR) is a novel refrigerating device that refrigerates a medium by shock waves and expansion waves generated by gas pressure energy. In a typical GWR, the injection energy losses between the nozzle and the expansion tube are essential factors which influence the refrigeration efficiency. In this study, numerical simulations are used to analyze the underlying mechanism of the injection energy losses. The results of simulations show that the vortex loss, mixing energy loss, and oblique shock wave reflection loss are the main factors contributing to the injection energy losses in the expansion tube. Furthermore, the jet angle of the gas is found to dominate the injection energy losses. Therefore, the optimum jet angle is theoretically calculated based on the velocity triangle method. The value of the optimum jet angle is found to be 4^{circ }, 8^{circ }, and 12^{circ } when the refrigeration efficiency is the first-order, second-order, and third-order maximum value over all working ranges of jet frequency, respectively. Finally, a series of experiments are conducted with the jet angle ranging from -4^{circ } to 12^{circ } at a constant expansion ratio. The results indicate the optimal jet angle obtained by the experiments is in good agreement with the calculated value. The isentropic refrigeration efficiency increased by about 4 % after the jet angle was optimized.

Refrigeration generation using expander-generator units

Science.gov (United States)

Klimenko, A. V.; Agababov, V. S.; Koryagin, A. V.; Baidakova, Yu. O.

2016-05-01

The problems of using the expander-generator unit (EGU) to generate refrigeration, along with electricity were considered. It is shown that, on the level of the temperatures of refrigeration flows using the EGU, one can provide the refrigeration supply of the different consumers: ventilation and air conditioning plants and industrial refrigerators and freezers. The analysis of influence of process parameters on the cooling power of the EGU, which depends on the parameters of the gas expansion process in the expander and temperatures of cooled environment, was carried out. The schematic diagram of refrigeration generation plant based on EGU is presented. The features and advantages of EGU to generate refrigeration compared with thermotransformer of steam compressive and absorption types were shown, namely: there is no need to use the energy generated by burning fuel to operate the EGU; beneficial use of the heat delivered to gas from the flow being cooled in equipment operating on gas; energy production along with refrigeration generation, which makes it possible to create, using EGU, the trigeneration plants without using the energy power equipment. It is shown that the level of the temperatures of refrigeration flows, which can be obtained by using the EGU on existing technological decompression stations of the transported gas, allows providing the refrigeration supply of various consumers. The information that the refrigeration capacity of an expander-generator unit not only depends on the parameters of the process of expansion of gas flowing in the expander (flow rate, temperatures and pressures at the inlet and outlet) but it is also determined by the temperature needed for a consumer and the initial temperature of the flow of the refrigeration-carrier being cooled. The conclusion was made that the expander-generator units can be used to create trigeneration plants both at major power plants and at small energy.

Efficiency improvement of commercial refrigeration systems

Energy Technology Data Exchange (ETDEWEB)

Denecke, Julius [NTNU, Trondheim (Norway); Hafner, Armin [SINTEF Energy Research, Trondheim (Norway)

2011-07-01

This work presents a historical review of carbon dioxide refrigeration systems. Further a literature survey is carried out to get a status of existing refrigeration technology related to supermarkets. In the next step various energy saving options are stated. A heat recovery model, basing on a R744 booster refrigeration system is established and described. Simplified demand curves for refrigeration, air conditioning and heating will base this model to calculate different heat recovery layouts. Supermarket future trends will be considered and integrated in the calculation. Finally the calculated energy consumptions will be compared with real energy consumptions of selected supermarket refrigeration systems.

THERMODYNAMIC PROPERTIES OF SELECTED HFC REFRIGERANTS

Science.gov (United States)

Hydrofluorocarbon (HFC) refrigerants are possible alternatives to replace ozone-depleting chlorofluorocarbon and hydrochlorofluorocarbon (HCFC) refrigerants. The flammability of a proposed new refrigerant is a major consideration in assessing its utility for a particular applicat...

Overall performance of the duplex Stirling refrigerator

International Nuclear Information System (INIS)

Erbay, L. Berrin; Ozturk, M. Mete; Doğan, Bahadır

2017-01-01

Highlights: • Overall performance coefficient of duplex Stirling refrigerator was investigated. • A definite region for the coefficient of performance of the refrigerator in duplex Stirling is identified. • A definite region for the thermal efficiency of the heat engine in duplex Stirling is identified. • Benchmark values and design bounds of the duplex Stirling refrigerator were obtained. - Abstract: The duplex Stirling refrigerator is an integrated refrigerator consists of Stirling cycle engine and Stirling cycle refrigerator used for cooling. The equality of the work generation of the heat engine to the work consumption of the refrigerator is the primary constraint of the duplex Stirling. The duplex Stirling refrigerator is investigated thermodynamically by considering the effects of constructional and operational parameters which are namely the temperature ratios for heat engine and refrigerator, and the compression ratios for both sides. The primary concern is given to the parametric effects on the overall coefficient of performance of the duplex Stirling refrigerator. The given diagrams provide a design bounds and benchmark results that allows seeing the big picture about the cooling load and heat input relation. Moreover they ease to determine the corresponding work rate to the target cooling load. As regard to the obtained results, a definite region for coefficient of performance of the refrigerator and a definite region for the thermal efficiency of the heat engine of the duplex Stirling are identified.

An experimental investigation on a novel ejector enhanced refrigeration cycle applied in the domestic refrigerator-freezer

International Nuclear Information System (INIS)

Wang, Xiao; Yu, Jianlin

2015-01-01

This paper presents an experimental investigation on a NERC (novel ejector enhanced refrigeration cycle) applied in the domestic refrigerator-freezer (BCD-249). Experimental studies were conducted to validate the NERC system feasibility in a practical NERC based refrigerator-freezer prototype. The system performances of energy consumption, ejector pressure lift ratio and compressor power were compared under different combinations of system configuration parameters. The results showed that the NERC system could effectively reduce the thermodynamic losses in the throttle processing. The minimum energy consumption of 0.520 kWh 24 h"−"1 was obtained for the NERC prototype, indicating 5.45% energy consumption reduction compared with the conventional domestic refrigerator-freezer. Furthermore, the effects of system configuration parameters including the refrigerant charge amount, the compressor displacement and the length of capillary tube were investigated. This study aims at providing deep insight into ejector-expansion technology applied in domestic refrigerator-freezers. - Highlights: • A NERC (novel ejector enhanced refrigeration cycle) was experimentally studied. • 73 experimental data points with different system configuration were acquired. • Energy consumption could be reduced with optimum system configuration. • 5.45% energy consumption reduction is obtained compared with the conventional system.

Improving the energy efficiency of industrial refrigeration systems

International Nuclear Information System (INIS)

Oh, Jin-Sik; Binns, Michael; Park, Sangmin; Kim, Jin-Kuk

2016-01-01

Various retrofit design options are available for improving the energy efficiency and economics of industrial refrigeration systems. This study considers a novel retrofit option using a mixed refrigerant (MR) in refrigeration cycles designed for use with a pure refrigerant (PR). In this way energy savings can be realized by switching refrigerants without requiring extensive and expensive reconfiguration of equipment. Hence, the aim here is to test the common thinking that equipment should always be extensively reconfigured when switching from pure to mixed refrigerants. To determine the most energy-efficient operating conditions for each refrigeration design an optimization framework is utilized linking a process simulator with an external optimization method. A case study is presented to demonstrate how the proposed process modeling and optimization framework can be applied and to illustrate the economic benefits of using the retrofit design options considered here. For the case considered in this paper, savings of shaft power required for the refrigeration cycle can be achieved from 16.3% to 27.2% when the pure refrigerant is replaced with mixed refrigerants and operating conditions are re-optimized. - Highlights: • Design methods for the design of refrigeration cycles in retrofit cases. • Consideration of mixed refrigerants to the existing multi-level pure-refrigerant cycles. • Optimization of refrigeration cycles with integrated use of a process simulator with an optimizer.

Sorption by cation exchange

International Nuclear Information System (INIS)

Bradbury, M.H.; Baeyens, B.

1994-04-01

A procedure for introducing exchange into geochemical/surface complexation codes is described. Beginning with selectivity coefficients, K c , defined in terms of equivalent fractional ion occupancies, a general expression for the molar based exchange code input parameters, K ex , is derived. In natural systems the uptake of nuclides onto complex sorbents often occurs by more than one mechanism. The incorporation of cation exchange and surface complexation into a geochemical code therefore enables sorption by both mechanisms to be calculated simultaneously. The code and model concepts are tested against sets of experimental data from widely different sorption studies. A proposal is made to set up a data base of selectivity coefficients. Such a data base would form part of a more general one consisting of sorption mechanism specific parameters to be used in conjunction with geochemical/sorption codes to model and predict sorption. (author) 6 figs., 6 tabs., 26 refs

Influence of sorption competition on sorption data for MX-80 bentonite used in performance assessment

International Nuclear Information System (INIS)

Bradbury, M.H.; Baeyens, B.; Marques Fernandes, M.

2012-01-01

Document available in extended abstract form only. In order to obtain a (quasi) mechanistic understanding of radionuclide uptake on clay minerals and argillaceous rocks, the majority of sorption experiments have been carried out on purified clay minerals such as montmorillonite and illite at trace concentrations (sorption edges), or as a function of concentration (sorption isotherms), with a single radionuclide under well-defined conditions in simple background electrolytes. As a result of such studies the 2 site proto-lysis non electrostatic surface complexation cation exchange (2SPNE SC/CE) sorption model, was developed and has been successfully applied to quantitatively describe the uptake of numerous radionuclides of differing valences as a function of pH and concentration on montmorillonite. In a deep geological repository for high level waste, stable impurities arise from many sources: they are present in the pore waters, in the tunnel back fill materials and host rock formations, they arise from the corrosion of the carbon steel canister and finally they are dissolved from the spent fuel and vitrified high level waste simultaneously with the radionuclides. These impurities, which are an integral part of a realistic repository system, can potentially compete with radionuclides for the sorption sites on the backfill materials and host rock and thus reduce their uptake on them. The influence of competitive sorption is not intrinsically included (or only partly so) in the sorption model. It is clearly an inherently important issue to quantify the influence of sorption competition on the transport of released radionuclides through the multi-barrier system in a deep repository. In this study an extreme case of a competitive sorption scenario in the near field of a HLW repository is presented. Two factors are considered: one associated with the high concentrations and the other with competitive sorption effects. The tendency in both cases is to cause a reduction in

HeREF-2003: Helium Refrigeration Techniques

CERN Multimedia

2003-01-01

CERN Technical Training 2003: Learning for the LHC ! Theory, Technology, Maintenance and Control of Helium Refrigerators HeREF-2003 is a course in the framework of the 2002 Technical Training Programme, that will provide a complete introduction to Helium refrigeration, with a practical approach to theory, technology, maintenance and control of Helium refrigeration installations. Theoretical aspects and equations will be limited to a minimum. HeREF-2003 targets an audience of technicians and operators of Helium refrigeration plants at CERN, as well as physicists and engineers needing an overview of current Helium refrigeration techniques. HeREF-2003 will address, among other, issues related to component technology, installation maintenance, process control and Helium purity. A commented visit to a couple of CERN Helium refrigeration or liquefaction plants will also take place. Duration: 7 half days (4 mornings and 3 afternoons), 6-10 October, 2003 Cost per participant: 500.- CHF Language: Bilingual English...

HeREF-2003 : Helium Refrigeration Techniques

CERN Multimedia

2003-01-01

CERN Technical Training 2003: Learning for the LHC ! Theory, Technology, Maintenance and Control of Helium Refrigerators HeREF-2003 is a course in the framework of the 2002 Technical Training Programme, that will provide a complete introduction to Helium refrigeration, with a practical approach to theory, technology, maintenance and control of Helium refrigeration installations. Theoretical aspects and equations will be limited to a minimum. HeREF-2003 targets an audience of technicians and operators of Helium refrigeration plants at CERN, as well as physicists and engineers needing an overview of current Helium refrigeration techniques. HeREF-2003 will address, among other, issues related to component technology, installation maintenance, process control and Helium purity. A commented visit to a couple of CERN Helium refrigeration or liquefaction plants will also take place. • Duration: 7 half days (4 mornings and 3 afternoons), 6-10 October, 2003 • Cost per participant: 500.- CHF
...

Magnetocaloric refrigeration near room temperature (invited)

International Nuclear Information System (INIS)

Brueck, E.; Tegus, O.; Thanh, D.T.C.; Buschow, K.H.J.

2007-01-01

Modern society relies on readily available refrigeration. The ideal cooling machine would be a compact, solid state, silent and energy-efficient heat pump that does not require maintenance. Magnetic refrigeration has three prominent advantages compared to compressor-based refrigeration. First, there are no harmful gases involved, second it may be built more compact as the working material is a solid and third magnetic refrigerators generate much less noise. Recently, a new class of magnetic refrigerant materials for room-temperature applications was discovered. These new materials have important advantages over existing magnetic coolants: They exhibit a large magnetocaloric effect (MCE) in conjunction with a magnetic phase transition of first order. This MCE is, larger than that of Gd metal, which is used in the demonstration refrigerators built to explore the potential of this evolving technology. In the present review, we compare the different materials considering both scientific aspects and industrial applicability

Analysis of Refrigeration Cycle Performance with an Ejector

Directory of Open Access Journals (Sweden)

Wani J. R.

2016-01-01

Full Text Available A conventional refrigeration cycle uses expansion device between the condenser and the evaporator which has losses during the expansion process. A refrigeration cycle with ejector is a promising modification to improve the performance of conventional refrigeration cycle. The ejector is used to recover some of the available work so that the compressor suction pressure increases. To investigate the enhancement a model with R134a refrigerant was developed. To solve the set of equations and simulate the cycle performance a subroutine was written on engineering equation solver (EES environment. At specific conditions, the refrigerant properties are obtained from EES. At the design conditions the ejector refrigeration cycle achieved 5.141 COP compared to 4.609 COP of the conventional refrigeration cycle. This means that ejector refrigeration cycle offers better COP with 10.35% improvement compared to conventional refrigeration cycle. Parametric analysis of ejector refrigeration cycle indicated that COP was influenced significantly by evaporator and condenser temperatures, entrainment ratio and diffuser efficiency.

Development of Low Global Warming Potential Refrigerant Solutions for Commercial Refrigeration Systems using a Life Cycle Climate Performance Design Tool

Energy Technology Data Exchange (ETDEWEB)

Abdelaziz, Omar [ORNL; Fricke, Brian A [ORNL; Vineyard, Edward Allan [ORNL

2012-01-01

Commercial refrigeration systems are known to be prone to high leak rates and to consume large amounts of electricity. As such, direct emissions related to refrigerant leakage and indirect emissions resulting from primary energy consumption contribute greatly to their Life Cycle Climate Performance (LCCP). In this paper, an LCCP design tool is used to evaluate the performance of a typical commercial refrigeration system with alternative refrigerants and minor system modifications to provide lower Global Warming Potential (GWP) refrigerant solutions with improved LCCP compared to baseline systems. The LCCP design tool accounts for system performance, ambient temperature, and system load; system performance is evaluated using a validated vapor compression system simulation tool while ambient temperature and system load are devised from a widely used building energy modeling tool (EnergyPlus). The LCCP design tool also accounts for the change in hourly electricity emission rate to yield an accurate prediction of indirect emissions. The analysis shows that conventional commercial refrigeration system life cycle emissions are largely due to direct emissions associated with refrigerant leaks and that system efficiency plays a smaller role in the LCCP. However, as a transition occurs to low GWP refrigerants, the indirect emissions become more relevant. Low GWP refrigerants may not be suitable for drop-in replacements in conventional commercial refrigeration systems; however some mixtures may be introduced as transitional drop-in replacements. These transitional refrigerants have a significantly lower GWP than baseline refrigerants and as such, improved LCCP. The paper concludes with a brief discussion on the tradeoffs between refrigerant GWP, efficiency and capacity.

49 CFR 173.174 - Refrigerating machines.

Science.gov (United States)

2010-10-01

... 49 Transportation 2 2010-10-01 2010-10-01 false Refrigerating machines. 173.174 Section 173.174 Transportation Other Regulations Relating to Transportation PIPELINE AND HAZARDOUS MATERIALS SAFETY... Refrigerating machines. A refrigerating machine assembled for shipment and containing 7 kg (15 pounds) or less...

Modeling the adsorption of mixed gases based on pure gas adsorption properties

NARCIS (Netherlands)

Tzabar, N.; Holland, H. J.; Vermeer, C. H.; Ter Brake, H. J.M.

2015-01-01

Sorption-based Joule-Thomson (JT) cryocoolers usually operate with pure gases. A sorption-based compressor has many benefits; however, it is limited by the pressure ratios it can provide. Using a mixed-refrigerant (MR) instead of a pure refrigerant in JT cryocoolers allows working at much lower

Thermodynamic analysis of hydrocarbon refrigerants in a sub-cooling refrigeration system

Directory of Open Access Journals (Sweden)

BUKOLA O. BOLAJI

2013-06-01

Full Text Available In this study, the performance simulation of some hydrocarbon refrigerants (R290, R600 and R600a as alternatives to R134a in refrigeration system with sub-cooling is conducted by thermodynamic calculation of performance parameters using the REFPROP software. The results obtained showed that the saturated vapour pressure and temperature characteristic profiles for R600 and R600a are very close to that of R134a. The three hydrocarbon refrigerants exhibited very high refrigerating effect and condenser duty than R134a. The best of these parameters was obtained using R600. The discharge temperatures obtained using R600 and R600a were low, while that of R290 was very much higher. The highest coefficient of performance (COP and relative capacity index were obtained using R600. Average COPs of R600 and R600a are 4.6 and 2.2% higher than that of R134a, respectively. The performances of R600 and R600a in system were better than those of R134a and R290. The best performance was obtained using R600 in the system.

ARTI Refrigerant Database

Energy Technology Data Exchange (ETDEWEB)

Calm, J.M.

1992-11-09

The database provides bibliographic citations and abstracts for publications that may be useful in research and design of air- conditioning and refrigeration equipment. The database identifies sources of specific information on R-32, R-123, R-124, R-125, R-134, R-134a, R-141b, R-142b, R-143a, R-152a, R-245ca, R-290 (propane), R- 717 (ammonia), ethers, and others as well as azeotropic and zeotropic and zeotropic blends of these fluids. It addresses lubricants including alkylbenzene, polyalkylene glycol, ester, and other synthetics as well as mineral oils. It also references documents on compatibility of refrigerants and lubricants with metals, plastics, elastomers, motor insulation, and other materials used in refrigerant circuits. A computerized version is available that includes retrieval software.

Data-Driven Control of Refrigeration System

DEFF Research Database (Denmark)

Vinther, Kasper

Refrigeration is used in a wide range of applications, e.g., for storage of food at low temperatures to prolong shelf life and in air conditioning for occupancy comfort. The main focus of this thesis is control of supermarket refrigeration systems. This market is very competitive and it is import......Refrigeration is used in a wide range of applications, e.g., for storage of food at low temperatures to prolong shelf life and in air conditioning for occupancy comfort. The main focus of this thesis is control of supermarket refrigeration systems. This market is very competitive...... traditionally are a pressure and a temperature sensor. In this thesis, a novel maximum slope-seeking (MSS) control method is developed. This has resulted in a control implementation, which successfully has been able to control the evaporator superheat in four widely different refrigeration system test...... problems. The method utilizes the qualitative nonlinearity in the system and harmonic analysis of a perturbation signal to reach an unknown, but suitable, operating point. Another important control task in refrigeration systems is to maintain the temperature of the refrigerated space or foodstuff within...

Thermodynamic analysis of an absorption refrigeration system with ionic-liquid/refrigerant mixture as a working fluid

International Nuclear Information System (INIS)

Kim, Yoon Jo; Kim, Sarah; Joshi, Yogendra K.; Fedorov, Andrei G.; Kohl, Paul A.

2012-01-01

Thermodynamics of an ionic-liquid (IL) based absorption refrigeration system has been numerically analyzed. It provides an alternative to the normally toxic working fluids, such as the ammonia in conventional absorption systems. The use of ILs also eliminates crystallization and metal-compatibility problems of the water/LiBr system. Mixtures of refrigerants and imidazolium-based ILs are theoretically explored as the working fluid pairs in a miniature absorption refrigeration system, so as to utilize waste-heat to power a refrigeration/heat pump system for electronics cooling. A non-random two-liquid (NRTL) model was built and used to predict the solubility of the mixtures. Saturation temperatures at the evaporator and condenser were set at 25 °C and 50 °C, respectively, with the power dissipation of 100 W. Water in combination with [emim][BF 4 ] (1-ethyl-3-methylimidazolium tetrafluoroborate) gave the highest coefficient of performance (COP) around 0.9. The refrigerant/IL compatibility indicated by the circulation ratio, alkyl chain length of the IL, and thermodynamic properties of the refrigerants, such as latent heat of evaporation were proven to be important factors in determining the performance of the absorption system. The negative effect of high viscosity was mitigated by dilution of the IL with the refrigerant and the use of slightly larger microfluidic channel heat exchangers. -- Highlights: ► Mixtures of refrigerant/ionic-liquid are studied for absorption system. ► We carry out comprehensive theoretical thermodynamic analysis. ► The essential factors of refrigerant/IL affecting the performance are identified. ► Water/[emim][BF 4 ] showed the best performance of COP. ► The effects of high viscosity ILs on the system performance are not significant.

Thermoacoustic refrigerator for space applications

Science.gov (United States)

Garrett, Steven L.; Adeff, Jay A.; Hofler, Thomas J.

1993-10-01

A new spacecraft cryocooler which uses resonant high-amplitude sound waves in inert gases to pump heat is described. The phasing of the thermoacoustic cycle is provided by thermal conduction. This 'natural' phasing allows the entire refrigerator to operate with only one moving part (the loudspeaker diaphragm). A space-qualified thermoacoustic refrigerator was flown on the Space Shuttle Discovery (STS-42) in January, 1992. It was entirely autonomous, had no sliding seals, required no lubrication, used mostly low-tolerance machined parts, and contained no expensive components. Thermoacoustics is shown to be a competitive candidate for food refrigerator/freezers and commercial/residential air conditioners. The design and performance of the Space Thermo/Acoustic Refrigerator (STAR) is described.

A miniature adsorption3HE refrigerator

International Nuclear Information System (INIS)

Duband, L.; Ravex, A.; Lange, A.

1991-01-01

A self-contained, recyclable laboratory 3 He refrigerator has been developed. The refrigerator is very compact, portable and is designed to be safe and reliable. The unit can easily be installed on the cold plate of a superfluid 4 He cryostat. Once bolted on the cold plate, operation of the refrigerator is controlled by a single heater. In this new design the refrigerator has a cylindrical geometry. The adsorption pump is placed above the condensation point to prevent convection during the condensation phase and to improve the pumping speed. The inhibition of convection reduces the load on the 4 He bath and increases the condensation efficiency. This refrigeration technique has great potential for space applications. The absence of moving parts makes the system reliable and vibration free. Its simplicity and the absence of external components facilitate its integration on a cryostat. In fact, a rocket-borne 3 He refrigerator has already been successfully flown and has demonstrated the feasibility of this method

Sorption of actinides onto nanodiamonds

Energy Technology Data Exchange (ETDEWEB)

Buchatskaya, Yulia; Romanchuk, Anna; Yakovlev, Ruslan; Kulakova, Inna [Lomonosov Moscow State Univ., Moscow (Russian Federation). Dept. of Chemistry; Shiryaev, Andrei [Russian Academy of Sciences, Moscow (Russian Federation). Frumkin Institute of Physical Chemistry and Electrochemistry; Russian Academy of Sciences, Moscow (Russian Federation). Inst. of Geology of Ore Deposits, Petrography, Mineralogy and Geochemistry; Kalmykov, Stepan [Lomonosov Moscow State Univ., Moscow (Russian Federation). Dept. of Chemistry; Russian Academy of Sciences, Moscow (Russian Federation). Frumkin Institute of Physical Chemistry and Electrochemistry; Russian Academy of Sciences, Moscow (Russian Federation). Vernadsky Institute of Geochemistry and Analytical Chemistry

2015-06-01

Detonation nanodiamonds (ND) present a significant part of nanocarbons group, which could be produced on commercial scale by detonation of explosives in a closed chamber. Their unique properties of high surface area, low weight and radiation resistance make ND a prospective candidate for applications in sorption processes in radiochemistry. To study the influence of surface chemistry on sorption properties, apristine sample of ND was treated with acids and hydrogen. The surface chemistry of the samples was characterised by infrared spectroscopy, X-ray photoelectron spectroscopy and Boehm titration. The sorption properties of ND were tested fordifferent radionuclides. The sorption capacity of ND was shown to be higher than those of commonly used radionuclide sorbents like activated carbon and compariable to other members of nanocarbon group like graphene oxide and carbon nanotubes. The sorption properties were shown to be influenced by the presence of oxygen-containing groups on the surface of ND. This represents an opportunity to increase the sorption capacity of ND.

Sorption of actinides onto nanodiamonds

International Nuclear Information System (INIS)

Buchatskaya, Yulia; Romanchuk, Anna; Yakovlev, Ruslan; Kulakova, Inna; Shiryaev, Andrei; Russian Academy of Sciences, Moscow; Kalmykov, Stepan; Russian Academy of Sciences, Moscow; Russian Academy of Sciences, Moscow

2015-01-01

Detonation nanodiamonds (ND) present a significant part of nanocarbons group, which could be produced on commercial scale by detonation of explosives in a closed chamber. Their unique properties of high surface area, low weight and radiation resistance make ND a prospective candidate for applications in sorption processes in radiochemistry. To study the influence of surface chemistry on sorption properties, apristine sample of ND was treated with acids and hydrogen. The surface chemistry of the samples was characterised by infrared spectroscopy, X-ray photoelectron spectroscopy and Boehm titration. The sorption properties of ND were tested fordifferent radionuclides. The sorption capacity of ND was shown to be higher than those of commonly used radionuclide sorbents like activated carbon and compariable to other members of nanocarbon group like graphene oxide and carbon nanotubes. The sorption properties were shown to be influenced by the presence of oxygen-containing groups on the surface of ND. This represents an opportunity to increase the sorption capacity of ND.

Not all counterclockwise thermodynamic cycles are refrigerators

Science.gov (United States)

Dickerson, R. H.; Mottmann, J.

2016-06-01

Clockwise cycles on PV diagrams always represent heat engines. It is therefore tempting to assume that counterclockwise cycles always represent refrigerators. This common assumption is incorrect: most counterclockwise cycles cannot be refrigerators. This surprising result is explored here for quasi-static ideal gas cycles, and the necessary conditions for refrigeration cycles are clarified. Three logically self-consistent criteria can be used to determine if a counterclockwise cycle is a refrigerator. The most fundamental test compares the counterclockwise cycle with a correctly determined corresponding Carnot cycle. Other criteria we employ include a widely accepted description of the functional behavior of refrigerators, and a corollary to the second law that limits a refrigerator's coefficient of performance.

Cryogenic mixed refrigerant processes

CERN Document Server

Venkatarathnam, Gadhiraju

2010-01-01

Teaches the need for refrigerant mixtures, the type of mixtures that can be used for different refrigeration and liquefaction applications, the different processes that can be used and the methods to be adopted for choosing the components of a mixture and their concentration for different applications.

PCB congener sorption to carbonaceous sediment components: Macroscopic comparison and characterization of sorption kinetics and mechanism

International Nuclear Information System (INIS)

Choi, Hyeok; Al-Abed, Souhail R.

2009-01-01

Sorption of polychlorinated biphenyls (PCBs) to sediment is a key process in determining their mobility, bioavailability, and chemical decomposition in aquatic environments. In order to examine the validity of currently used interpretation approaches for PCBs sorption, comparative results on 2-chlorobiphenyl sorption to carbonaceous components in sediments (activated carbon, carbon black, coal, soot, graphite, flyash, wood) were macroscopically correlated with the structural, morphological, crystallographic, and compositional properties of the carbonaceous components. Since the Freundlich sorption constant, K F (L kg -1 ) spanned several orders of magnitude, ranging from log K F of 6.13-5.27 for activated carbon, 5.04 for carbon black, 3.83 for coal to 3.08 for wood, organic carbon partitioning approach should be more specifically categorized, considering the various forms, nature and origins of organic carbon in sediment. Sorption rate constants and fraction parameters, which were numerically defined from empirical kinetic model with fast and slow sorption fractions, were closely related to the physicochemical properties of the carbonaceous components. Sorption interpretation approaches with a specific property and viewpoint, such as organic carbon partitioning, soot carbon distribution, or surface area correlation, did not properly explain the overall results on sorption capacity, fast and slow sorption kinetics, and partitioning coefficient. It is also important to emphasize the heterogeneous nature of sediment and the difficulties of encompassing the partitioning among its carbonaceous components.

PCB congener sorption to carbonaceous sediment components: Macroscopic comparison and characterization of sorption kinetics and mechanism

Energy Technology Data Exchange (ETDEWEB)

Choi, Hyeok [National Risk Management Research Laboratory, U.S. Environmental Protection Agency, 26 West Martin Luther King Drive, Cincinnati, OH 45268 (United States); Al-Abed, Souhail R., E-mail: al-abed.souhail@epa.gov [National Risk Management Research Laboratory, U.S. Environmental Protection Agency, 26 West Martin Luther King Drive, Cincinnati, OH 45268 (United States)

2009-06-15

Sorption of polychlorinated biphenyls (PCBs) to sediment is a key process in determining their mobility, bioavailability, and chemical decomposition in aquatic environments. In order to examine the validity of currently used interpretation approaches for PCBs sorption, comparative results on 2-chlorobiphenyl sorption to carbonaceous components in sediments (activated carbon, carbon black, coal, soot, graphite, flyash, wood) were macroscopically correlated with the structural, morphological, crystallographic, and compositional properties of the carbonaceous components. Since the Freundlich sorption constant, K{sub F} (L kg{sup -1}) spanned several orders of magnitude, ranging from log K{sub F} of 6.13-5.27 for activated carbon, 5.04 for carbon black, 3.83 for coal to 3.08 for wood, organic carbon partitioning approach should be more specifically categorized, considering the various forms, nature and origins of organic carbon in sediment. Sorption rate constants and fraction parameters, which were numerically defined from empirical kinetic model with fast and slow sorption fractions, were closely related to the physicochemical properties of the carbonaceous components. Sorption interpretation approaches with a specific property and viewpoint, such as organic carbon partitioning, soot carbon distribution, or surface area correlation, did not properly explain the overall results on sorption capacity, fast and slow sorption kinetics, and partitioning coefficient. It is also important to emphasize the heterogeneous nature of sediment and the difficulties of encompassing the partitioning among its carbonaceous components.

Thermoacoustic engines and refrigerators

Energy Technology Data Exchange (ETDEWEB)

Swift, G.

1996-12-31

This report is a transcript of a practice lecture given in preparation for a review lecture on the operation of thermoacoustic engines and refrigerators. The author begins by a brief review of the thermodynamic principles underlying the operation of thermoacoustic engines and refrigerators. Remember from thermodynamics class that there are two kinds of heat engines, the heat engine or the prime mover which produces work from heat, and the refrigerator or heat pump that uses work to pump heat. The device operates between two thermal reservoirs at temperatures T{sub hot} and T{sub cold}. In the heat engine, heat flows into the device from the reservoir at T{sub hot}, produces work, and delivers waste heat into the reservoir at T{sub cold}. In the refrigerator, work flows into the device, lifting heat Q{sub cold} from reservoir at T{sub cold} and rejecting waste heat into the reservoir at T{sub hot}.

United States: refrigeration industry blows hot

International Nuclear Information System (INIS)

Crawford, J.

1997-01-01

In the framework of the Kyoto convention on global warming, the american refrigeration industries have undertaken several organizations and contacts with governments and agencies in order to explain the real issues concerning the effects of refrigerant utilization in refrigerating machines on the greenhouse effect, taking into consideration the commercial impact that a ban on certain refrigerants could have on the industry's business. They argue that HFC utilization in this industry is fundamentally non-emissive and that important improvements have been realized concerning tightness and energy consumption

Sorption of short-lived radionuclides in a layer of sorbent with spherical granules

International Nuclear Information System (INIS)

Karlin, Yu.V.

1993-01-01

Sorption methods have found wide application in the purification of liquid radioactive wastes. The working element in sorption methods for this purpose is usually a sorption column with a fixed layer of sorbent. Continuous-action equipment with a moving layer of sorbent is very seldom used. When a fixed layer of sorbent is used its wear and prolonged mixing in the sorption column are reduced to a minimum, and maximum purification is achieved due to the advantages of the dynamic method of sorption over the static method. The time of protective action of the sorbent layer is determined by the time taken for the radionuclide to pass through the sorption column, and for the majority of radionuclides is determined by numerous parameters, including the type of sorbent and radionuclide, the rate of flow through the sorbent, the size of the sorbent granules, etc. The physical and chemical aspects of this process have been investigated in detail, and numerous methods for modeling it mathematically have been developed and have been used to develop methods of designing sorption column apparatus. The specific nature of the radionuclides as unstable materials enables the hypothetical case of a open-quotes perpetualclose quotes sorption filter to be represented. In fact, to achieve this it is only necessary to assume that the half-life of the radionuclide is so small that the rate of decay of the radionuclide in the sorption column (both in the sorbed state and in the aqueous phase of the sorption layer) is equal to the rate that it is fed into the column in the flow of liquid radioactive waste. In this case the sorption front of the radionuclide in the column wall remains fixed after a certain initial period. In this paper, a mathematical model of such a hypothetical filter for the case of spherical sorbent granules is considered

46 CFR 154.702 - Refrigerated carriage.

Science.gov (United States)

2010-10-01

... Pressure and Temperature Control § 154.702 Refrigerated carriage. (a) Each refrigeration system must: (1) Have enough capacity to maintain the cargo vapor pressure in each cargo tank served by the system below... the purpose of this section, a “refrigeration unit” includes a compressor and its motors and controls...

Solar Refrigerators Store Life-Saving Vaccines

Science.gov (United States)

2014-01-01

Former Johnson Space Center engineer David Bergeron used his experience on the Advanced Refrigeration Technology Team to found SunDanzer Refrigeration Inc., a company specializing in solar-powered refrigerators. The company has created a battery-free unit that provides safe storage for vaccines in rural and remote areas around the world.

Simulation of absorption refrigeration system for automobile application

Directory of Open Access Journals (Sweden)

Ramanathan Anand

2008-01-01

Full Text Available An automotive air-conditioning system based on absorption refrigeration cycle has been simulated. This waste heat driven vapor absorption refrigeration system is one alternate to the currently used vapour compression refrigeration system for automotive air-conditioning. Performance analysis of vapor absorption refrigeration system has been done by developing a steady-state simulation model to find the limitation of the proposed system. The water-lithium bromide pair is used as a working mixture for its favorable thermodynamic and transport properties compared to the conventional refrigerants utilized in vapor compression refrigeration applications. The pump power required for the proposed vapor absorption refrigeration system was found lesser than the power required to operate the compressor used in the conventional vapor compression refrigeration system. A possible arrangement of the absorption system for automobile application is proposed.

Next Generation Refrigeration Lubricants for Low Global Warming Potential/Low Ozone Depleting Refrigeration and Air Conditioning Systems

Energy Technology Data Exchange (ETDEWEB)

Hessell, Edward

2013-12-31

The goal of this project is to develop and test new synthetic lubricants that possess high compatibility with new low ozone depleting (LOD) and low global warming potential (LGWP) refrigerants and offer improved lubricity and wear protection over current lubricant technologies. The improved compatibility of the lubricants with the refrigerants, along with improved lubricating properties, will resulted in lower energy consumption and longer service life of the refrigeration systems used in residential, commercial and industrial heating, ventilating and air-conditioning (HVAC) and refrigeration equipment.

An Evaluation of the Environmental Impact of Different Commercial Supermarket Refrigeration Systems Using Low Global Warming Potential Refrigerants

Energy Technology Data Exchange (ETDEWEB)

Beshr, Mohamed [University of Maryland, College Park; Aute, Vikrant [University of Maryland, College Park; Abdelaziz, Omar [ORNL; Fricke, Brian A [ORNL; Radermacher, Reinhard [University of Maryland, College Park

2014-01-01

Commercial refrigeration systems consumed 1.21 Quads of primary energy in 2010 and are known to be a major source for refrigerant charge leakage into the environment. Thus, it is important to study the environmental impact of commercial supermarket refrigeration systems and improve their design to minimize any adverse impacts. The system s Life Cycle Climate Performance (LCCP) was presented as a comprehensive metric with the aim of calculating the equivalent mass of carbon dioxide released into the atmosphere throughout its lifetime, from construction to operation and destruction. In this paper, an open source tool for the evaluation of the LCCP of different air-conditioning and refrigeration systems is presented and used to compare the environmental impact of a typical multiplex direct expansion (DX) supermarket refrigeration systems based on three different refrigerants as follows: two hydrofluorocarbon (HFC) refrigerants (R-404A, and R-407F), and a low global warming potential (GWP) refrigerant (N-40). The comparison is performed in 8 US cities representing different climates. The hourly energy consumption of the refrigeration system, required for the calculation of the indirect emissions, is calculated using a widely used building energy modeling tool (EnergyPlus). A sensitivity analysis is performed to determine the impact of system charge and power plant emission factor on the LCCP results. Finally, we performed an uncertainty analysis to determine the uncertainty in total emissions for both R-404A and N-40 operated systems. We found that using low GWP refrigerants causes a considerable drop in the impact of uncertainty in the inputs related to direct emissions on the uncertainty of the total emissions of the system.

Review of investigations in eco-friendly thermoacoustic refrigeration system

Directory of Open Access Journals (Sweden)

Raut Ashish S.

2017-01-01

Full Text Available To reduce greenhouse gas emissions, internationally research and development is intended to improve the performance of conventional refrigeration system also growth of new-fangled refrigeration technology of potentially much lesser ecological impact. This paper gives brief review of research and development in thermoacoustic refrigeration also the existing situation of thermoacoustic refrigeration system. Thermoacoustic refrigerator is a novel sort of energy conversion equipment which converts acoustic power into heat energy by thermoacoustic effect. Thermoacoustic refrigeration is an emergent refrigeration technology in which there are no moving elements or any environmentally injurious refrigerants during its working. The concept of thermoacoustic refrigeration system is explained, the growth of thermoacoustic refrigeration, various investigations into thermoacoustic refrigeration system, various optimization techniques to improve coefficient of performance, different stacks and resonator tube designs to improve heat transfer rate, various gases, and other parameters like sound generation have been reviewed.

A new compressed air energy storage refrigeration system

International Nuclear Information System (INIS)

Wang Shenglong; Chen Guangming; Fang Ming; Wang Qin

2006-01-01

In this study, a new compressed air energy storage (CAES) refrigeration system is proposed for electrical power load shifting application. It is a combination of a gas refrigeration cycle and a vapor compression refrigeration cycle. Thermodynamic calculations are conducted to investigate the performance of this system. Economic analysis is performed to study the operating cost of the system, and comparison is made with a vapor compression refrigeration system and an ice storage refrigeration system. The results indicate that the CAES refrigeration system has the advantages of simple structure, high efficiency and low operating cost

Web-based sorption database (KAERI-SDB)

International Nuclear Information System (INIS)

Lee, Jae Kwang; Baik, Min Hoon

2010-10-01

Radionuclide sorption data is necessary for the safety assessment of radioactive waste disposal. However the accessibility to the nuclide sorption database is limited. The web-based sorption database (KAERI-SDB) was developed to provide sorption data in a convenient way. The development of the KAERI-SDB was achieved by improving the performance of pre-existing sorption DB programme (SDB-21C) and incorporating the user requirement. The KAERI-SDB was designed that users can access it by using a web browser. Main functions of the KAERI-SDB include (1) log-in/join, (2) search and store of sorption data and (3) scatter plot chart and index chart. It is expected that the KAERI-SDB is widely applied to the safety assessment of radioactive waste disposal by enhancing the accessibility to experts and practitioner related the nuclear industry and governmental administration. It is also expected that reliabilities for the radioactive waste disposal increased by opening the web-based sorption DB to public

Quality Model of Foodstuff in the Control of Refrigerated Display Cabinet

DEFF Research Database (Denmark)

Cai, Junping; Risum, Jørgen; Thybo, Claus

2006-01-01

Commercial refrigerating systems need to be defrosted regularly to maintain a satisfactory performance. When defrosting the evaporator coil, the air temperature inside the display cabinet will increase, and float outside the normal temperature range for a period of time, the question is what...... happens to the food inside during this period, when we look at the quality factor? This paper discusses quality model of foodstuff, different scenarios of defrost scheme are simulated, questions such as how the defrost temperature and duration influence the food temperature, thus the food quality, as well...... as what is the optimal defrost scheme from food quality point of view are answered. This will serve as a prerequisite of designing of optimal control scheme for the commercial refrigeration system, aiming at optimizing a weighed cost function of both food quality and overall energy consumption of system....

Zero boil-off methods for large-scale liquid hydrogen tanks using integrated refrigeration and storage

Science.gov (United States)

Notardonato, W. U.; Swanger, A. M.; E Fesmire, J.; Jumper, K. M.; Johnson, W. L.; Tomsik, T. M.

2017-12-01

NASA has completed a series of tests at the Kennedy Space Center to demonstrate the capability of using integrated refrigeration and storage (IRAS) to remove energy from a liquid hydrogen (LH2) tank and control the state of the propellant. A primary test objective was the keeping and storing of the liquid in a zero boil-off state, so that the total heat leak entering the tank is removed by a cryogenic refrigerator with an internal heat exchanger. The LH2 is therefore stored and kept with zero losses for an indefinite period of time. The LH2 tank is a horizontal cylindrical geometry with a vacuum-jacketed, multilayer insulation system and a capacity of 125,000 liters. The closed-loop helium refrigeration system was a Linde LR1620 capable of 390W cooling at 20K (without any liquid nitrogen pre-cooling). Three different control methods were used to obtain zero boil-off: temperature control of the helium refrigerant, refrigerator control using the tank pressure sensor, and duty cycling (on/off) of the refrigerator as needed. Summarized are the IRAS design approach, zero boil-off control methods, and results of the series of zero boil-off tests.

SIMULATION OF NON-AZEOTROPIC REFRIGERANT MIXTURES FOR USE IN A DUAL-CIRCUIT REFRIGERATOR/FREEZER WITH COUNTERCURRENT HEAT EXCHANGES

Science.gov (United States)

The paper discusses a refrigerator/freezer (RF) system that has two complete and independent refrigeration cycles for the two compartments. It uses a non-azeotropic refrigerant mixture (NARM) in each cycle and countercurrent heat exchangers throughout. This RF is housed in a stan...

Polyhalogenated hydrocarbon refrigerants and refrigerant oils colored with fluorescent dyes and method for their use as leak detectors

Energy Technology Data Exchange (ETDEWEB)

Parekh, M.

1988-07-19

A leak detectable refrigeration composition is described comprising: (A) a refrigeration liquid selection from the group consisting of: (1) a polyhalogenated hydrocarbon refrigerant; (2) a refrigeration oil selected from the group consisting of naphthenic oils, paraffinic oils, alkylated benzenes, silicones, polyglycols, diesters or triesters of dicarboxylic or tricarboxylic acids, and polyalkyl silicate oils, and (3) a mixture of A(1) and A(2), and (B) a fluorescent dye compound or composition comprising the dye selected from the group consisting of: (1) a fluorescent dye selected from the group consisting of perylene, naphthoxanthene, monocyclic aromatic compounds having an organometallic compound, (2) a solution of fluorescent dye in a solvent, and (3) a mixture of B(1) and B(2). The fluorescent dye compound or composition is soluble in the refrigeration liquid. The concentration of the dye being at least 0.001 grams per 100 grams of the refrigeration liquid.

Automated energy conserving cover for refrigerated cabinet access openings

International Nuclear Information System (INIS)

Ibrahim, F.F.

1984-01-01

An automatically operated flexible barrier cover for the access openings of refrigerated display cabinets. The barrier cover limits the contact between the refrigerated air within the cabinet and the ambient air. The barrier cover can be moved over the access opening during non-customer use time periods when the retail food outlet is closed. The barrier cover can be arranged as a unitary assembly which can be manufactured and sold separately from the display cabinet as a retrofit device to effect energy savings. The flexible barrier cover can be stored in a reeled-up position or can be arranged as a folded flexible barrier which can be fanned out across the access opening. Various traction means are provided for moving the flexible barrier across the access opening

Experimental Study On Thermal Wave Type Adsorption Refrigeration System Working On A Pair Of Activated Carbon And Methanol

Directory of Open Access Journals (Sweden)

Grzebielec Andrzej

2015-12-01

Full Text Available The aim of the study was to examine the efficiency of the thermal wave type adsorption refrigerating equipment working on a pair of activated carbon and methanol. Adsorption units can work in trigeneration systems and in applications driven by waste heat. They can be built also as a part of hybrid sorption-compressor systems, and they are very popular in solar refrigeration systems and energy storage units. The device examined in this study operates in a special mode called thermal wave. This mode allows to achieve higher efficiency rates than the normal mode of operation, as a significant contributor to transport heat from one to the other adsorber. To carry out the experiment a test bench was built, consisting of two cylindrical adsorbers filled with activated carbon, condenser, evaporator, oil heater and two oil coolers. Thermal oil circulation was responsible for providing and receiving heat from adsorbers. In order to perform the correct action a special control algorithm device was developed and implemented to keep the temperature in the evaporator at a preset level. The experimental results show the operating parameters changes in both adsorbers. Obtained COP (coefficient of performance for the cycle was 0.13.

High temperature refrigerator

International Nuclear Information System (INIS)

Steyert, W.A. Jr.

1978-01-01

A high temperature magnetic refrigerator is described which uses a Stirling-like cycle in which rotating magnetic working material is heated in zero field and adiabatically magnetized, cooled in high field, then adiabatically demagnetized. During this cycle the working material is in heat exchange with a pumped fluid which absorbs heat from a low temperature heat source and deposits heat in a high temperature reservoir. The magnetic refrigeration cycle operates at an efficiency 70% of Carnot

Refrigerant charge management in a heat pump water heater

Science.gov (United States)

Chen, Jie; Hampton, Justin W.

2014-06-24

Heat pumps that heat or cool a space and that also heat water, refrigerant management systems for such heat pumps, methods of managing refrigerant charge, and methods for heating and cooling a space and heating water. Various embodiments deliver refrigerant gas to a heat exchanger that is not needed for transferring heat, drive liquid refrigerant out of that heat exchanger, isolate that heat exchanger against additional refrigerant flowing into it, and operate the heat pump while the heat exchanger is isolated. The heat exchanger can be isolated by closing an electronic expansion valve, actuating a refrigerant management valve, or both. Refrigerant charge can be controlled or adjusted by controlling how much liquid refrigerant is driven from the heat exchanger, by letting refrigerant back into the heat exchanger, or both. Heat pumps can be operated in different modes of operation, and segments of refrigerant conduit can be interconnected with various components.

Refrigeration: Introducing energy saving opportunities for business

Energy Technology Data Exchange (ETDEWEB)

NONE

2006-04-15

In some industries, most notably food and drink and chemicals, refrigeration accounts for a significant proportion of overall site energy costs. For instance, in the industrial handling of meat, poultry and fish, it often accounts for 50% of total energy costs. In ice-cream production the proportion is 70%. In a number of commercial sectors, refrigeration also represents a significant proportion of overall energy costs. For example: Cold storage 90%; Food supermarkets 50%; Small shops with refrigerated cabinets 70% or over; Pubs and clubs 30%. Against these high costs, even a small reduction in refrigeration energy use can offer significant cost savings, resulting in increased profits. Energy saving need not be expensive. Energy savings of up to 20% can be realised in many refrigeration plant through actions that require little or no investment. In addition, improving the efficiency and reducing the load on a refrigeration plant can improve reliability and reduce the likelihood of a breakdown. Most organisations can save energy and money on refrigeration by: More efficient equipment; Good maintenance; Housekeeping and control. This publication provides an understanding of the operation of refrigeration systems, identifies where savings can be realised and will enable readers to present an informed case on energy savings to key decision makers within their organisation. (GB)

Environmentally benign working pairs for adsorption refrigeration

International Nuclear Information System (INIS)

Cui Qun; Tao Gang; Chen Haijun; Guo Xinyue; Yao Huqing

2005-01-01

This paper begins from adsorption working pairs: water and ethanol were selected as refrigerants; 13x molecular sieve, silica gel, activated carbon, adsorbent NA and NB, proposed by authors, were selected as adsorbents, and the performance of adsorption working pairs in adsorption refrigeration cycle was studied. The adsorption isotherms of adsorbents (NA and NB) were obtained by high-vacuum gravimetric method. Desorption properties of adsorbents were analyzed and compared by thermal analysis method. The performance of adsorption refrigeration was studied on simulation device of adsorption refrigeration cycle. After presentation of adsorption isotherms, the thermodynamic performance for their use in adsorption refrigeration system was calculated. The results show: (1) the maximum adsorption capacity of water on adsorbent NA reaches 0.7 kg/kg, and the maximum adsorption capacity of ethanol on adsorbent NB is 0.68 kg/kg, which is three times that of ethanol on activated carbon, (2) the refrigeration capacity of NA-water working pair is 922 kJ/kg, the refrigeration capacity of NB-ethanol is 2.4 times that of activated carbon-methanol, (3) as environmental friendly and no public hazard adsorption working pair, NA-H 2 O and NB-ethanol can substitute activated carbon-methanol in adsorption refrigeration system using low-grade heat source

Mountain Plains Learning Experience Guide: Heating, Refrigeration, & Air Conditioning.

Science.gov (United States)

Carey, John

This Heating, Refrigeration, and Air Conditioning course is comprised of eleven individualized units: (1) Refrigeration Tools, Materials, and Refrigerant; (2) Basic Heating and Air Conditioning; (3) Sealed System Repairs; (4) Basic Refrigeration Systems; (5) Compression Systems and Compressors; (6) Refrigeration Controls; (7) Electric Circuit…

2014 German refrigeration and air conditioning meeting. Proceedings

International Nuclear Information System (INIS)

2014-01-01

The proceedings of the 2014 German refrigeration and air conditioning meeting contain contributions on the following topics: cryotechnology, fundamentals and materials for the refrigeration and heat pump technology, devices and components for the refrigeration and heat pump technology, applications of refrigeration technologies, air conditioning technology and heat pump applications, cryotechnology in biology and medicine, heat transfer and ventilation, guidelines and legal topics, refrigerant fluid - oil mixtures, control and surveillance, simulation and control, ambient air.

Control of the Tevatron Satellite Refrigeration system

International Nuclear Information System (INIS)

Theilacker, J.; Chapman, L.; Gannon, J.; Hentges, M.; Martin, M.; Rode, C.H.; Zagel, J.

1984-01-01

This chapter describes a computerized control system for 24 satellite refrigerators which cool a six kilometer ring of superconducting magnets. The control system consists of 31 independent microprocessors operating over 400 servo loops, and a central computer system which provides monitoring, alarms, logging and changing of parameters. Topics considered include pressure measurement, flow measurement, temperature measurement, gas analysis, control valves, expansion engine controllers, and control loops. Each refrigerator has 12 active microprocessor based control loops which tune the refrigerator to one of its four operating modes: satellite, liquefier, refrigerator, and stand-by. It is suggested that optimizing the refrigerator control loops and quench recovery scheme will minimize the accelerator down time

Performance characteristics of a quantum Diesel refrigeration cycle

International Nuclear Information System (INIS)

He Jizhou; Wang Hao; Liu Sanqiu

2009-01-01

The Diesel refrigeration cycle using an ideal quantum gas as the working substance is called quantum Diesel refrigeration cycle, which is different from Carnot, Ericsson, Brayton, Otto and Stirling refrigeration cycles. For ideal quantum gases, a corrected equation of state, which considers the quantum behavior of gas particles, is used instead of the classical one. The purpose of this paper is to investigate the effect of quantum gas as the working substance on the performance of a quantum Diesel refrigeration cycle. It is found that coefficients of performance of the cycle are not affected by the quantum degeneracy of the working substance, which is the same as that of the classical Diesel refrigeration cycle. However, the refrigeration load is different from those of the classical Diesel refrigeration cycle. Lastly, the influence of the quantum degeneracy on the performance characteristics of the quantum Diesel refrigeration cycle operated in different temperature regions is discussed

ARTI refrigerant database. Quarterly report, March--May 1997

Energy Technology Data Exchange (ETDEWEB)

Calm, J.M.

1997-05-01

The Refrigerant Database is an information system on alternative refrigerants, associated lubricants, and their use in air conditioning and refrigeration. It consolidates and facilitates access to property, compatibility, environmental, safety, application and other information. It provides corresponding information an older refrigerants, to assist manufacturers and those using alternative refrigerants, to make comparisons and determine differences. The underlying purpose is to accelerate phase out of chemical compounds of environmental concern. The database provides bibliographic citations and abstracts for publications that may be useful in research and design of air-conditioning and refrigeration equipment. The complete documents are not included, though some may be added at a later date.

Optimum operating regimes of common paramagnetic refrigerants

CERN Document Server

Wikus, P; Figueroa-Feliciano, E

2011-01-01

Adiabatic Demagnetization Refrigerators (ADRs) are commonly used in cryogenic laboratories to achieve subkelvin temperatures. ADRs are also the technology of choice for several space borne instruments which make use of cryogenic microcalorimeters or bolometers {[}1-4]. For these applications, refrigerants with high ratios of cooling capacity to volume, or cooling capacity to mass are usually required. In this manuscript, two charts for the simple selection of the most suitable of several common refrigerants (CAA, CMN, CPA, DGG, FAA, GGG, GLF and MAS) are presented. These graphs are valid for single stage cycles. The selection of the refrigerants is uniquely dependent on the starting conditions of the refrigeration cycle (temperature and magnetic field density) and the desired final temperature. Only thermodynamic properties of the refrigerants have been taken into account, and other important factors such as availability and manufacturability have not been considered. (C) 2011 Elsevier Ltd. All rights reserve...

A study of sorption of cadmium by goethite in aqueous solution

Directory of Open Access Journals (Sweden)

N. Salami

2002-06-01

Full Text Available Investigation has been carried out on the potential of a locally sourced goethite for the removal of cadmium ion from aqueous solutions using batch equilibration technique. The maximum uptake of cadmium is 6.4  10-2 mg/g-goethite. The sorption kinetics appears to be rapid as equilibrium was attained within a period of 1 hour. The highest sorption capacity was obtained for particle size with diameter (Φ 0.09 mm. Both infrared spectrophotometric and X-ray diffraction (XRD techniques have also provided evidence for cadmium fixation on to the surface of the goethite. The sorption mechanism appears to follow Langmuir adsorption isotherm model. The Langmuir constants K and Xm (mass of Cd2+ required to form monolayer on the entire surface of the goethite were 0.096 mg/g-goethite and 0.075 mg/g-goethite, respectively.

Compatibility of refrigerants and lubricants with elastomers

Energy Technology Data Exchange (ETDEWEB)

Hamed, G.R.; Seiple, R.H.

1993-01-01

The information contained in this report is designed to assist the air-conditioning and refrigeration industry in the selection of suitable elastomeric gasket and seal materials that will prove useful in various refrigerant and refrigeration lubricant environments. 97% of the swell measurements have been made to date. The other 3% of the measurements are contingent on availability of additional R-32. Swell behavior in the fluids have been determined using weight and in situ diameter measurements for the refrigerants and weight, diameter and thickness measurements for the lubricants. Weight and diameter measurements are repeated after 2 and 24 hours for samples removed from the refrigerant test fluids and 24 hours after removal from the lubricants.

Storing meat products without refrigeration for several years

International Nuclear Information System (INIS)

1973-01-01

Irradiation sterilization (radappertization) can be used successfully to store ham, bacon, pork, pork sausage, beef, corned beef, chicken, codfish cakes, and shrimp for long periods under non-refrigerated conditions. he technical feasibility of using ionizing radiations to preserve such highly perishable protein foods has been proven under the U.S. Army Radiation Preservation of Foods Programme, and technology is far enough advanced to carry this out. (author)

Experiments with a pressure-driven Stirling refrigerator with flexible chambers

Science.gov (United States)

McFarlane, Patrick; Suire, Jonathan; Sen, Mihir; Semperlotti, Fabio

2014-06-01

We report on the design and experimental testing of a Stirling refrigerator that uses air as the working fluid, and where the conventional piston-cylinder assemblies are replaced by pressure-driven flexible chambers. The two chambers are periodically compressed by pneumatic actuators resulting in airflow through the regenerator and in a net temperature difference between the chambers. An experimental setup is used to investigate the performance of the refrigerator under different operating conditions with particular attention to actuation frequencies, driving pressure differences, and phase angles between the two inputs. The time constant of the temperature difference between the two chambers is determined, and the temperature difference is measured as a function of the system parameters. The results of several tests conducted under different operating conditions show that the refrigerating effect is very robust and allows good performance even for modulated inputs. The frequency response is radically different from that of a traditional motion-driven device. This work suggests that mechanical to thermal energy conversion devices based on this principle can be successfully powered by human motion.

Refrigeration a history

CERN Document Server

Gantz, Carroll

2015-01-01

For thousands of years, humans coped with heat by harvesting and storing natural ice and devising natural cooling systems that utilized ventilation and evaporation. By the mid 1800s, people began developing huge refrigeration machines to manufacture ice. By the early 1900s, engineers developed electric domestic refrigerators, which by 1927 were affordable convenient household appliances. By then, an increasingly sophisticated public demanded more modern-looking appliances than engineers could produce, and a new breed of designers entered the manufacturing world to provide them. During the Depr

Refrigerating liquid prototype for LED's thermal management

International Nuclear Information System (INIS)

Faranda, Roberto; Guzzetti, Stefania; Lazaroiu, George Cristian; Leva, Sonia

2012-01-01

The heat management is the critical factor for high performance operation of LED. A new heat management application of refrigerating liquid integrated within a fabricated prototype is proposed and investigated. A series of experiments considering different heights of liquid level were performed to evaluate the heat dissipation performance and optical characteristics of the refrigerating liquid based prototype. The results reveal that the junction temperature decreases as the level of refrigerating liquid increases. The experimental results report that the refrigerating liquid reduces the junction temperature, and can positively influence the luminous radiation performances. An optimization investigation of the proposed solution was carried out to find an optimum thermal performance. The experiments indicated that refrigerating liquid cooling is a powerful way for heat dissipation of high power LEDs, and the fabrication of prototype was feasible and useful. - Highlights: ► New heat management application of refrigerating liquid on a fabricated LED prototype. ► Thermal models setup and comparison between the classical and the new solutions. ► The impact of refrigerating liquid level on LED thermal and luminous performances. ► The relationship between different levels of liquid with LED prototype performances.

IEA Annex 26: Advanced Supermarket Refrigeration/Heat Recovery Systems

Energy Technology Data Exchange (ETDEWEB)

Baxter, VAN

2003-05-19

With increased concern about the impact of refrigerant leakage on global warming, a number of new supermarket refrigeration system configurations requiring significantly less refrigerant charge are being considered. In order to help promote the development of advanced systems and expand the knowledge base for energy-efficient supermarket technology, the International Energy Agency (IEA) established IEA Annex 26 (Advanced Supermarket Refrigeration/Heat Recovery Systems) under the ''IEA Implementing Agreement on Heat Pumping Technologies''. Annex 26 focuses on demonstrating and documenting the energy saving and environmental benefits of advanced systems design for food refrigeration and space heating and cooling for supermarkets. Advanced in this context means systems that use less energy, require less refrigerant and produce lower refrigerant emissions. Stated another way, the goal is to identify supermarket refrigeration and HVAC technology options that reduce the total equivalent warming impact (TEWI) of supermarkets by reducing both system energy use (increasing efficiency) and reducing total refrigerant charge. The Annex has five participating countries: Canada, Denmark, Sweden, the United Kingdom, and the United States. The working program of the Annex has involved analytical and experimental investigation of several candidate system design approaches to determine their potential to reduce refrigerant usage and energy consumption. Advanced refrigeration system types investigated include the following: distributed compressor systems--small parallel compressor racks are located in close proximity to the food display cases they serve thus significantly shortening the connecting refrigerant line lengths; secondary loop systems--one or more central chillers are used to refrigerate a secondary coolant (e.g. brine, ice slurry, or CO2) that is pumped to the food display cases on the sales floor; self-contained display cases--each food display case

Sorption mechanisms of perfluorinated compounds on carbon nanotubes

International Nuclear Information System (INIS)

Deng Shubo; Zhang Qiaoying; Nie Yao; Wei Haoran; Wang Bin; Huang Jun; Yu Gang; Xing Baoshan

2012-01-01

Sorption of perfluorinated compounds (PFCs) on carbon nanotubes (CNTs) is critical for understanding their subsequent transport and fate in aqueous environments, but the sorption mechanisms remain largely unknown. In this study, the sorption of six PFCs on CNTs increased with increasing C-F chain length when they had a same functional group, and the CNTs with hydroxyl and carboxyl groups had much lower adsorbed amount than the pristine CNTs, indicating that hydrophobic interaction dominated the sorption of PFCs on the CNTs. Electrostatic repulsion suppressed the sorption of PFCs on the CNTs, resulting in the lower sorption with increasing pH. Hydrogen bonding interaction was negligible. The hydrophobic C-F chains can be closely adsorbed on the CNTs surface in parallel to the axis or along the curvature, making it impossible to form micelles on the CNT surface, leading to the lower sorption than other adsorbents. Highlights: ► Sorption capacities of PFOA on different CNTs are less than that on activated carbon and resins. ► Hydrophobic interaction is principally involved in the sorption of PFCs on CNTs. ► Electrostatic repulsion suppresses the sorption of PFCs on CNTs. - Hydrophobic interaction dominated the sorption of perfluorinated compounds on carbon nanotubes, while electrostatic repulsion suppressed their sorption.

Sorption equilibria of ethanol on cork.

Science.gov (United States)

Lequin, Sonia; Chassagne, David; Karbowiak, Thomas; Bellat, Jean-Pierre

2013-06-05

We report here for the first time a thermodynamic study of gaseous ethanol sorption on raw cork powder and plate. Our study aims at a better understanding of the reactivity of this material when used as a stopper under enological conditions, thus in close contact with a hydroethanolic solution, wine. Sorption−desorption isotherms were accurately measured by thermogravimetry at 298 K in a large range of relative pressures. Sorption enthalpies were determined by calorimetry as a function of loading. Sorption−desorption isotherms exhibit a hysteresis loop probably due to the swelling of the material and the absorption of ethanol. Surprisingly, the sorption enthalpy of ethanol becomes lower than the liquefaction enthalpy as the filling increases. This result could be attributed to the swelling of the material, which would generate endothermic effects. Sorption of SO₂ on cork containing ethanol was also studied. When the ethanol content in cork is 2 wt %, the amount of SO₂ sorbed is divided by 2. Thus, ethanol does not enhance the sorption rate for SO₂ but, on the contrary, decreases the SO₂ sorption activity onto cork, probably because of competitive sorption mechanisms.

Metal sorption on kaolinite

International Nuclear Information System (INIS)

Westrich, H.R.; Brady, P.V.; Cygan, R.T.; Nagy, K.L.; Anderson, H.L.

1997-01-01

A key issue in performance assessment of low-level radioactive waste sites is predicting the transport and retardation of radionuclides through local soils under a variety of hydrologic and geochemical conditions. Improved transport codes should include a mechanistic model of radionuclide retardation. The authors have been investigating metal sorption (Cs + , Sr 2+ , and Ba 2+ ) on a simple clay mineral (kaolinite) to better understand the geochemical interactions of common soil minerals with contaminated groundwaters. These studies include detailed characterizations of kaolinite surfaces, experimental adsorption measurements, surface complexation modeling, and theoretical simulations of cation sorption. The aluminol edge (010) site has been identified as the most likely site for metal sorption on kaolinite in natural solutions. Relative metal binding strengths decrease from Ba 2+ to Sr 2+ to Cs + , with some portion sorbed on both kaolinite edges and basal surfaces. Some Cs + also appears to be irreversibly sorbed on both sites. Molecular dynamics simulations suggest that Cs + is sorbed at aluminol (010) edge sites as an inner-sphere complex and weakly sorbed as an outer-sphere complex on (001) basal surfaces. These results provide the basis to understand and predict metal sorption onto kaolinite, and a framework to characterize sorption processes on more complex clay minerals

Design and Simulation of a Vapour Compression Refrigeration System Using Phase Change Material

Directory of Open Access Journals (Sweden)

Siddharth Raju

2018-01-01

Full Text Available The paper details the design and simulation of a solar powered vapour compression refrigeration system. The effect of a phase change material, in this case ice, on a vapour compression refrigeration system powered by solar panels is discussed. The battery and solar panels were sized to allow the system to function as an autonomous unit for a minimum of 12 hours. It was concluded that the presence of a phase change material in the refrigeration system caused a considerable increase in both the on and off time of the compressor. The ratio by which the on time increased was greater than the ratio by which the off time was increased. There was a 219% increase in the on time, a 139% increase in the compressor off time and a 3.5% increase in compressor work accompanied by a 5.5% reduction in COP. Thus, under conditions where there is enough load in the system to cause the initial on and off times of the compressor to be comparable, the presence of a phase change material may result in a greater on period than an off period for the compressor.

Energy optimisation of domestic refrigerators

DEFF Research Database (Denmark)

Jakobsen, Arne; Rasmussen, Bjarne D.

1998-01-01

This paper describes the main results of a research project with the objective of reducing the energy consumption of domestic refrigerators by increasing the efficiency of the refrigeration system. The improvement of the system efficiency was to be obtained by:1) Introducing continuous operation ...

Operating Manual of Helium Refrigerator (Rev. 2)

Energy Technology Data Exchange (ETDEWEB)

Song, K.M.; Son, S.H.; Kim, K.S.; Lee, S.K.; Kim, M.S. [Korea Electric Power Research Institute, Taejon (Korea)

2002-07-01

A helium refrigerator was installed as a supplier of 20K cold helium to the cryogenic distillation system of WTRF pilot plant. The operating procedures of the helium refrigerator, helium compressor and auxiliary apparatus are described for the safety and efficient operation in this manual. The function of the helium refrigerator is to remove the impurities from the compressed helium of about 250psig, to cool down the helium from ambient temperature to 20K through the heat exchanger and expansion engine and to transfer the cold helium to the cryogenic distillation system. For the smoothly operation of helium refrigerator, the preparation, the start-up, the cool-down and the shut-down of the helium refrigerator are described in this operating manual. (author). 3 refs., 14 tabs.

Manufacturing A Refrigerator with Heat Recovery Unit

Directory of Open Access Journals (Sweden)

Mustafa Mohammed Kadhim

2018-02-01

Full Text Available This study aims to exploite the rejected heating energy from condenser and benefit from it to reheat the foods and other materials. It can also be employed to improve the coefficient of performance of a refrigerator at the same time by using approximately the same consumption electrical energy used to operate the compressor and refrigerator in general. This idea has been implemented by manufacturing of a refrigerator with using additional part has the same metal and condenser pipe diameters but its surface area does not exceed 40% from total surface area of the condenser and its design as an insulated cabinet from all sides to prevent heat leakage through it and located between the compressor and the condenser. Small electrical fan has been added inside this cabinet to provide a suitable air circulation and a homogenous temperature distribution inside the cabinet space. It is expected that the super heating energy of refrigerant (R134a which comes out of the compressor would be removed  inside this cabinet and this insist to condensate the refrigerant (cooling fluid with a rate higher than that used in the normal refrigerator only. Three magnetic valves have been used in order to control the refrigerant flow in state of operation the refrigerator only or to gather with heating cabinet. To measure the temperatures at each process of the simple vapor compression refrigeration cycle, nine temperature sensors at input and output of each compressor, condenser and an evaporator in additional to input of cabinet and inside it and on evaporator surface have been provided. Five pressure gages have been used to measure the value of pressure and compare it for the two states of operation. The consumption of electrical energy  can be calculated by adding an ammeter and a voltmeter and compare between the consumption energy of both states. The obtained results show that there is an improvement in the coeffecient of performance in state of operation the

Development of mechanistic sorption model and treatment of uncertainties for Ni sorption on montmorillonite/bentonite

International Nuclear Information System (INIS)

Ochs, Michael; Ganter, Charlotte; Tachi, Yukio; Suyama, Tadahiro; Yui, Mikazu

2011-02-01

Sorption and diffusion of radionuclides in buffer materials (bentonite) are the key processes in the safe geological disposal of radioactive waste, because migration of radionuclides in this barrier is expected to be diffusion-controlled and retarded by sorption processes. It is therefore necessary to understand the detailed/coupled processes of sorption and diffusion in compacted bentonite and develop mechanistic /predictive models, so that reliable parameters can be set under a variety of geochemical conditions relevant to performance assessment (PA). For this purpose, JAEA has developed the integrated sorption and diffusion (ISD) model/database in montmorillonite/bentonite systems. The main goal of the mechanistic model/database development is to provide a tool for a consistent explanation, prediction, and uncertainty assessment of K d as well as diffusion parameters needed for the quantification of radionuclide transport. The present report focuses on developing the thermodynamic sorption model (TSM) and on the quantification and handling of model uncertainties in applications, based on illustrating by example of Ni sorption on montmorillonite/bentonite. This includes 1) a summary of the present state of the art of thermodynamic sorption modeling, 2) a discussion of the selection of surface species and model design appropriate for the present purpose, 3) possible sources and representations of TSM uncertainties, and 4) details of modeling, testing and uncertainty evaluation for Ni sorption. Two fundamentally different approaches are presented and compared for representing TSM uncertainties: 1) TSM parameter uncertainties calculated by FITEQL optimization routines and some statistical procedure, 2) overall error estimated by direct comparison of modeled and experimental K d values. The overall error in K d is viewed as the best representation of model uncertainty in ISD model/database development. (author)

Neptunium(V) sorption on kaolinite

Energy Technology Data Exchange (ETDEWEB)

Amayri, S.; Jermolajev, A.; Reich, T. [Mainz Univ. (Germany). Inst. of Nuclear Chemistry

2011-07-01

The sorption behavior of neptunium(V) onto the clay mineral kaolinite was studied in batch experiments under different experimental conditions: [Np(V)] = 7 x 10{sup -12}-8 x 10{sup -6} M, solid-to-liquid ratio 2-20 g L{sup -1}, I = 0.1 and 0.01 M NaClO{sub 4}, pH = 6-10, ambient air and Ar atmosphere. The short-lived isotope {sup 239}Np (T{sub 1/2} = 2.36 d) was used instead of {sup 237}Np (T{sub 1/2} = 2.14 x 10{sup 6} a) to study the sorption behavior of Np(V) at environmentally-relevant concentrations, i.e., 7 x 10{sup -12} M Np. In addition, {sup 239}Np(V) served as tracer to measure sorption isotherms over six orders of magnitude in Np concentration (4.8 x 10{sup -12}-1.0 x 10{sup -4} M). The results show that Np(V) sorption on kaolinite is strongly influenced by pH, CO{sub 2}, and ionic strength. The sorption of 8 x 10{sup -6} M Np(V) at pH 9.0, and ionic strength of 0.1 M NaClO{sub 4} was proportional to the solid-to-liquid ratio of kaolinite in the range of 2-10 g L{sup -1}. In the absence of CO{sub 2}, the Np(V) uptake increased continuously with increasing pH value up to 97% at pH 10. Under ambient CO{sub 2}, the sorption of Np decreased above pH 8 up to zero at pH 10. An increase of Np(V) concentration from 7 x 10{sup -12} to 8 x 10{sup -6} M resulted in a shift of the sorption pH edge by up to one pH unit to higher pH values. The ionic strength influenced the Np(V) sorption onto kaolinite only in the presence of ambient CO{sub 2}. Under Ar atmosphere the sorption of Np(V) was independent from ionic strength, indicating the formation of inner-sphere complexes of Np(V) with kaolinite. Time-dependent batch experiments at pH 9.0 under ambient CO{sub 2} showed that the sorption of Np(V) on kaolinite is fast and fully reversible over six orders in Np(V) concentration. (orig.)

Sorption properties of wool

Directory of Open Access Journals (Sweden)

Radetić Maja M.

2004-01-01

Full Text Available Strict ecological legislation, especially in highly developed countries, imposed requirements for the purification of industrial effluents and the need for efficient oil clean up after sea and inland water spills. Although numerous processes have been developed, the application of sorbents is still one of the most efficient methods to remove heavy metal ions, dyes and crude oil from water. Recently, special attention was paid to sorbents based on natural fibres. A review of studies concerning the sorption properties of wool is presented in this paper. The presence of various functional groups on the wool fibre surface contributes to the efficient sorption of heavy metal ions and dyes. A hydrophobic, scaly surface and fibre crimp strongly influence the high sorption capacity of wool for oil. Wool has great sorption potential even as a recycled material. Accordingly, it can be used as a viable substitute to commercially available synthetic sorbents that show poor biodegradab ility.

HFC perspectives in air-conditioning and refrigeration; Perspectives HFC en A/C et refrigeration

Energy Technology Data Exchange (ETDEWEB)

Fauvarque, P [ELF Atochem, Centre d` Application de Lavallois, 92 (France)

1998-12-31

This paper is a series of transparencies dealing with the development of substitutes for the replacement of the R-22 refrigerant in air-conditioning systems (R-134a, R-407C, R-410A), and in industrial refrigeration systems of agriculture and food industry (R-134a and R-404A). (J.S.)

HFC perspectives in air-conditioning and refrigeration; Perspectives HFC en A/C et refrigeration

Energy Technology Data Exchange (ETDEWEB)

Fauvarque, P. [ELF Atochem, Centre d`Application de Lavallois, 92 (France)

1997-12-31

This paper is a series of transparencies dealing with the development of substitutes for the replacement of the R-22 refrigerant in air-conditioning systems (R-134a, R-407C, R-410A), and in industrial refrigeration systems of agriculture and food industry (R-134a and R-404A). (J.S.)

Acquisition of sorption isotherms for modified woods by the use of dynamic vapour sorption instrumentation. Principles and Practice

DEFF Research Database (Denmark)

Engelund, Emil Tang; Klamer, Morten; Venås, Thomas Mark

2010-01-01

The complex wood-water relationship has been the topic of numerous studies. Sorption isotherms – in particular – have been derived for hundreds of wood species, their sap- and heartwood sections as well as for decayed, engineered and modified wood materials. However, the traditional methods...... for obtaining sorption isotherms are very time consuming. With new dynamic vapour sorption (DVS) instrumentation, the acquisition of data for constructing sorption isotherms is suddenly dramatically lowered. Where the traditional methods often required months, data can now be obtained in a matter of days...... depending on the number of data points required. The fast data acquisition makes DVS a useful tool in studying the sorption properties of wood, and especially in studying the effect of different modification treatments on these properties. This study includes an investigation of the sorption properties...

Modeling and calculation of open carbon dioxide refrigeration system

International Nuclear Information System (INIS)

Cai, Yufei; Zhu, Chunling; Jiang, Yanlong; Shi, Hong

2015-01-01

Highlights: • A model of open refrigeration system is developed. • The state of CO 2 has great effect on Refrigeration capacity loss by heat transfer. • Refrigeration capacity loss by remaining CO 2 has little relation to the state of CO 2 . • Calculation results are in agreement with the test results. - Abstract: Based on the analysis of the properties of carbon dioxide, an open carbon dioxide refrigeration system is proposed, which is responsible for the situation without external electricity unit. A model of open refrigeration system is developed, and the relationship between the storage environment of carbon dioxide and refrigeration capacity is conducted. Meanwhile, a test platform is developed to simulation the performance of the open carbon dioxide refrigeration system. By comparing the theoretical calculations and the experimental results, several conclusions are obtained as follows: refrigeration capacity loss by heat transfer in supercritical state is much more than that in two-phase region and the refrigeration capacity loss by remaining carbon dioxide has little relation to the state of carbon dioxide. The results will be helpful to the use of open carbon dioxide refrigeration

Rotary magnetic refrigerator for superfluid helium production

International Nuclear Information System (INIS)

Hakuraku, Y.; Ogata, H.

1986-01-01

A new rotary-magnetic refrigerator designed to obtain superfluid helium temperatures by executing a magnetic Carnot cycle is developed. A rotor containing 12 magnetic refrigerants (gadolinium-gallium-garnet) is immersed in liquid helium at 4.2 K and rotated at constant speed in a steady magnetic field distribution. Performance tests demonstrate that the new rotary refrigerator is capable of obtaining a temperature of 1.48 K. The maximum useful cooling power obtained at 1.8 K is 1.81 W which corresponds to a refrigeration efficiency of 34%

New magnetic refrigeration materials for the liquefaction of hydrogen

International Nuclear Information System (INIS)

Gschneidner, K.A.; Takeya, H.; Moorman, J.O.; Pecharsky, V.K.; Malik, S.K.; Zimm, C.B.

1994-01-01

Five heavy lanthanide ferromagnetic intermetallic compounds were studied as potential magnetic refrigerants for the liquefaction of hydrogen gas. (Dy 0.5 Er 0.5 )Al 2 and TbNi 2 appear to be better refrigerants than GdPd for a Joule-Brayton cycle refrigerator, while (Gd 0.54 Er 0.46 )AlNi seems to be a suitable refrigerant for an Ericsson cycle refrigerator

Sorption and desorption kinetics of diuron, fluometuron, prometryn and pyrithiobac sodium in soils.

Science.gov (United States)

Baskaran, S; Kennedy, I R

1999-11-01

The sorption and desorption characteristics of four herbicides (diuron, fluometuron, prometryn and pyrithiobac-sodium) in three different cotton growing soils of Australia was investigated. Kinetics and equilibrium sorption and desorption isotherms were determined using the batch equilibrium technique. Sorption was rapid (> 80% in 2 h) and sorption equilibrium was achieved within a short period of time (ca 4 h) for all herbicides. Sorption isotherms of the four herbicides were described by Freundlich equation with an r2 value > 0.98. The herbicide sorption as measured by the distribution coefficient (Kd) values ranged from 3.24 to 5.71 L/kg for diuron, 0.44 to 1.13 L/kg for fluometuron, 1.78 to 6.04 L/kg for prometryn and 0.22 to 0.59 L/kg for pyrithiobac-sodium. Sorption of herbicides was higher in the Moree soil than in Narrabri and Wee Waa soils. When the Kd values were normalised to organic carbon content of the soils (Koc), it suggested that the affinity of the herbicides to the organic carbon increased in the order: pyrithiobac-sodium diuron. The desorption isotherms were also adequately described by the Freundlich equation. For desorption, all herbicides exhibited hysteresis and the hysteresis was stronger for highly sorbed herbicides (diuron and prometryn) than the weakly sorbed herbicides (fluometuron and pyrithiobac-sodium). Hysteresis was also quantified as the percentage of sorbed herbicides which is not released during the desorption step (omega = [nad/nde - 1] x 100). Soil type and initial concentration had significant effect on omega. The effect of sorption and desorption properties of these four herbicides on the off-site transport to contaminate surface and groundwater are also discussed in this paper.

Reasearch and Evaluation of Electromagnetic Fields of Refrigerators

Directory of Open Access Journals (Sweden)

Pranas Baltrėnas

2013-12-01

Full Text Available The use of refrigerators causes the occurence of electromagnetic fields that are invisible and intangible, which therefore makes difficulties in protecting ourselves from them. A refrigerator is an irreplaceable item in domestic household and thus can be hardly ignored by a modern way of human life. In order to preserve the characteristics of products, the refrigerator must operate continuously (24 hrs a day, regardless of the time of the year. This results in a huge increase in electricity consumption, which leads to energy consumption related pollution of the environment emitting CO2 gas. On these grounds, it is necessary to assess electromagnetic fields created by the refrigerator. Studies on electromagnetic fields produced by refrigerators were conducted in domestic premises where people spent a significant part of the day. For comparison purposes, five different power refrigerators were chosen (1 – 0.20 kW; 2 – 0.25 kW; 3 – 0.30 kW; 4 – 0.35 kW; 5 – 0.40 kW. The obtained results, according to the parameters of their electromagnetic fields, were presented in graphs and charts and showed that the values of electric and magnetic intensity of refrigerators depended on the distance and the power of the refrigerator. The conducted research also disclosed that none of tested refrigerators exceeded the permissible limits of electromagnetic fields.Article in Lithuanian

Krypton based adsorption type cryogenic refrigerator

Science.gov (United States)

Jones, Jack A. (Inventor); Schember, Helene R. (Inventor)

1989-01-01

Krypton and a monolithic porous carbon such as Saran carbon are used respectively as the sorbate and sorbent of an adsorption type refrigerator to improve refrigeration efficiency and operational longevity.

Performance Evaluation of a Solar Adsorption Refrigeration System with a Wing Type Compound Parabolic Concentrator

OpenAIRE

Umair, Muhammad; Akisawa, Atsushi; Ueda, Yuki

2014-01-01

Simulation study of a solar adsorption refrigeration system using a wing type compound parabolic concentrator (CPC) is presented. The system consists of the wing type collector set at optimum angles, adsorption bed, a condenser and a refrigerator. The wing type collector captures the solar energy efficiently in the morning and afternoon and provides the effective temperature for a longer period of time compared to that achieved by a linear collector. The objectives of the study were to evalua...

Auto-refrigerating cascade for superconducting applications

International Nuclear Information System (INIS)

Forrest, S.M.; Hall, P.H.; Missimer, D.J.

1987-01-01

Extremely low temperatures, in the range of 230 to 90 K, are achieved in a single circuit compression refrigeration system operated by a conventional compressor. The system relies upon a series of intermediate cooling stages. The refrigerant is a mixture and the system employs fractional condensation, distillation, phase separation and intermediate heat transfer. Each stage includes the steps of withdrawing a portion of the liquid condensate from the compressed vapor-liquid refrigerant mixture which enters the stage. The withdrawn condensate is then throttled to a lower pressure and is mixed with the refrigerant being recycled to the compressor from the final evaporator. Evaporating the throttled condensate absorbs heat from and at least partially condenses the compressed uncondensed vapor in the compressed mixture

Effects of experimental parameters on the sorption of cesium, strontium, and uranium from saline groundwaters onto shales: Progress report

International Nuclear Information System (INIS)

Meyer, R.E.; Arnold, W.D.; Case, F.I.; O'Kelley, G.D.

1988-11-01

This report concerns an extension of the first series of experiments on the sorption properties of shales and their clay mineral components reported earlier. Studies on the sorption of cesium and strontium were carried out on samples of Chattanooga (Upper Dowelltown), Pierre, Green River Formation, Nolichucky, and Pumpkin Valley Shales that had been heated to 120/degree/C in a 0.1-mol/L NaCl solution for periods up to several months and on samples of the same shales which had been heated to 250/degree/C in air for six months, to simulate limiting scenarios in a HLW repository. To investigate the kinetics of the sorption process in shale/groundwater systems, strontium sorption experiments were done on unheated Pierre, Green River Formation, Nolichucky, and Pumpkin Valley Shales in a diluted, saline groundwater and in 0.03-mol/L NaHCO 3 , for periods of 0.25 to 28 days. Cesium sorption kinetics tests were performed on the same shales in a concentrated brine for the same time periods. The effect of the water/rock (W/R) ratio on sorption for the same combinations of unheated shales, nuclides, and groundwaters used in the kinetics experiments was investigated for a range of W/R ratios of 3 to 20 mL/g. Because of the complexity of the shale/groundwater interaction, a series of tests was conducted on the effects of contact time and W/R ratio on the pH of a 0.03-mol/L NaHCO 3 simulated groundwater in contact with shales. 8 refs., 12 figs., 15 tabs

46 CFR 147.90 - Refrigerants.

Science.gov (United States)

2010-10-01

.../ASHRAE 34-78 may be carried as ships' stores. (b) Refrigerants contained in a vessel's operating system... 46 Shipping 5 2010-10-01 2010-10-01 false Refrigerants. 147.90 Section 147.90 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) DANGEROUS CARGOES HAZARDOUS SHIPS' STORES Stowage and Other...

Phenanthrene sorption on biochar-amended soils

DEFF Research Database (Denmark)

Kahawaththa Gamage, Inoka Damayanthi Kumari; Moldrup, Per; Paradelo Pérez, Marcos

2014-01-01

on their influences on the sorption of environmental contaminants. In a field-based study at two experimental sites in Denmark, we investigated the effect of birch wood-derived biochar (Skogans kol) on the sorption of phenanthrene in soils with different properties. The soil sorption coefficient, Kd (L kg-1......), of phenanthrene was measured on sandy loam and loamy sand soils which have received from zero up to 100 t ha-1 of biochar. Results show that birch wood biochar had a higher Kd compared to soils. Furthermore, the application of birch wood biochar enhanced the sorption of phenanthrene in agricultural soils...... carbon, while it negatively correlated with clay content. The results also revealed that biochar-mineral interactions play an important role in the sorption of phenanthrene in biochar-amended soil....

46 CFR 111.79-15 - Receptacles for refrigerated containers.

Science.gov (United States)

2010-10-01

... 46 Shipping 4 2010-10-01 2010-10-01 false Receptacles for refrigerated containers. 111.79-15... ELECTRIC SYSTEMS-GENERAL REQUIREMENTS Receptacles § 111.79-15 Receptacles for refrigerated containers. Receptacles for refrigerated containers must meet one of the following: (a) Each receptacle for refrigerated...

THE STIRLING GAS REFRIGERATING MACHINE MECHANICAL DESIGN IMPROVING

Directory of Open Access Journals (Sweden)

V. V. Trandafilov

2016-06-01

Full Text Available To improve the mechanical design of the piston Stirling gas refrigeration machine the structural optimization of rotary vane Stirling gas refrigeration machine is carried out. This paper presents the results of theoretical research. Analysis and prospects of rotary vane Stirling gas refrigeration machine for domestic and industrial refrigeration purpose are represented. The results of a patent search by mechanisms of transformation of rotary vane machines are discussed.

THE STIRLING GAS REFRIGERATING MACHINE MECHANICAL DESIGN IMPROVING

Directory of Open Access Journals (Sweden)

V. V. Trandafilov

2016-02-01

Full Text Available To improve the mechanical design of the piston Stirling gas refrigeration machine the structural optimization of rotary vane Stirling gas refrigeration machine is carried out. This paper presents the results of theoretical research. Analysis and prospects of rotary vane Stirling gas refrigeration machine for domestic and industrial refrigeration purpose are represented. The results of a patent search by mechanisms of transformation of rotary vane machines are discussed

Contribution to the study of a magnetic refrigeration between 4.2 and 1.8 kelvin

International Nuclear Information System (INIS)

Delpuech, Claude.

1980-11-01

This thesis includes three parts. (1) Construction of a study alternating refrigerator. This is essentially a double acting machine, with ancillary refrigeration by helium expansion. This refrigerator operates in a liquid helium bath at 4.2 K and the cold source is a superfluid bath whose temperature can be brought down to 1.6 K. The magnetic components, actuated by a periodic translation movement, are magnetized cyclically in the 4.2 K bath, then demagnetized in the central bath forming the cold source. The bar slides in guide bearings, isolating the central chamber of the 4.2 K bath. This can be cooled through the copper wall by the refrigeration bath. A relief valve and a level gauge enable the operation of the ancillary refrigerator to be adjusted. A temperature of under 1.8 K was obtained in a superfluid bath at atmospheric pressure. (2) Study of possible thermal exchange improvements in supercritical helium by artificially creating turbulency between two walls. This study could concern rotary machines described in an addendum. (3) Some physical properties of paramagnetic rare earth salts are also studied [fr

Adsorption refrigeration technology theory and application

CERN Document Server

Wang, Ruzhu; Wu, Jingyi

2014-01-01

Gives readers a detailed understanding of adsorption refrigeration technology, with a focus on practical applications and environmental concerns Systematically covering the technology of adsorption refrigeration, this book provides readers with a technical understanding of the topic as well as detailed information on the state-of-the-art from leading researchers in the field. Introducing readers to background on the development of adsorption refrigeration, the authors also cover the development of adsorbents, various thermodynamic theories, the design of adsorption systems and adsorption refri

Hydration and sorption characteristics of a polyfunctional weak-base anion exchanger after the sorption of vanillin and ethylvanillin

Science.gov (United States)

Rodionova, D. O.; Voronyuk, I. V.; Eliseeva, T. V.

2016-07-01

Features of the sorption of substituted aromatic aldehydes by a weak-base anion exchanger under equilibrium conditions are investigated using vanillin and ethylvanillin as examples. Analysis of the sorption isotherms of carbonyl compounds at different temperatures allows us to calculate the equilibrium characteristics of their sorption and assess the entropy and enthalpy contributions to the energy of the process. Hydration characteristics of the macroporous weak-base anion exchanger before and after the sorption of aromatic aldehydes are compared.

Refrigeration plants using carbon dioxide as refrigerant: measuring and modelling the solubility and diffusion of carbon dioxide in polymers used as sealing materials

DEFF Research Database (Denmark)

von Solms, Nicolas; Kristensen, Jakob

2010-01-01

Because of increased environmental pressure, there is currently a movement away from more traditional refrigerants such as HCFC's toward refrigerants with lower global warming potential such as carbon dioxide (CO2). However, the use of CO2 as a refrigerant requires a refrigeration cycle...

Evaluation of synergistic effect in vacuum pack, refrigeration and irradiated treatments of minimally processed cassava

International Nuclear Information System (INIS)

Pedroso, Bianca Maria

2005-01-01

Cassava is cultivated almost all over the world and it is considered one of the most important nutritious sources of calories in the human diet. Cassava is a viable food against starvation in several poor areas of the world because it is an extremely resistant culture and may reach satisfactory economical yield. We utilized vacuum packed industrialized cassava irradiated with 0,1 kGy, 3kGy and 5kGy and stored under refrigeration for 1, 21, 30 and 50 days. Our objective was to analyse the synergistic effect of vacuum packing, irradiation and refrigeration on the preservation of minimally processed cassava. The samples were analyzed for pH, acidity, weight, humidity, texture and color. The irradiation did not affect the chemical characteristics of the cassava. Neither the pH nor the acidity, the most relevant variables to verify deterioration in cassava, presented significant alterations during the period of storage. Comparing the irradiated treatments, the dose of 1kGy and 3kGy affected the physic-chemical characteristics of the cassava the least during the period of storage and refrigeration for 50 days; the doses of 1kGy,3kGy and 5kGy scored the highest rates the sensorial analysis during the period of storage for 21 days. (author)

Refrigerated display cabinets; Butikskyla

Energy Technology Data Exchange (ETDEWEB)

Fahlen, Per

2000-07-01

This report summarizes experience from SP research and assignments regarding refrigerated transport and storage of food, mainly in the retail sector. It presents the fundamentals of heat and mass transfer in display cabinets with special focus on indirect systems and secondary refrigerants. Moreover, the report includes a brief account of basic food hygiene and the related regulations. The material has been compiled for educational purposes in the Masters program at Chalmers Technical University.

Analysis of cooldown performance for Isabelle helium refrigerator

International Nuclear Information System (INIS)

Wu, K.C.; Brown, D.P.; Moore, R.W.

1982-01-01

The cooldown performance for the ISABELLE Helium refrigerator is analyzed in terms of the relationship between refrigerator and its load. The flow diagram for ISABELLE with its redundant turbines and heat exchangers is given. Cycle description and procedure for cooldown is described with the relationship between a refrigerator and its load illustrated. Pressure vs. temperature for ISABELLE load and the efficiency for a turbine are illustrated. The procedure for modeling the refrigerator and the concepts of maximizing the cooldown capacity are described. The results and discussion are accompanied with T-S diagrams for initial stage of cooldown and refrigerator characteristic at various return temperatures. The ISABELLE refrigerator with its reduncant expanders properly used achieves cooldown capacity well beyond its steady-state capacity. The cooldown rate at this stage relies on the design safety margin, which for the ISABELLE is 50%

Sorption properties of carbon nanostructures

International Nuclear Information System (INIS)

Eletskii, Aleksandr V

2004-01-01

The current status of research in sorption properties of carbon nanotubes (CNTs) is reviewed. The structural peculiarities of CNTs, determining their sorption characteristics, are considered. The mechanisms of sorption of gaseous and condensed substances by such structures are analyzed. Special attention is paid to the problem of using CNTs for storing hydrogen and other gaseous substances. Methods for filling CNTs with liquid materials, based on capillary phenomena and wetting the graphite surface of the CNT with liquids of various nature, are considered. Properties of 'peapods' formed as a result of filling single-walled CNTs with fullerene molecules are reviewed. Also considered are perspectives on the applied usage of the sorption properties of CNTs in electrochemical and fuel cells, and material storage devices, as well as for producing superminiature metallic conductors. (reviews of topical problems)

Refrigeration system having standing wave compressor

Science.gov (United States)

Lucas, Timothy S.

1992-01-01

A compression-evaporation refrigeration system, wherein gaseous compression of the refrigerant is provided by a standing wave compressor. The standing wave compressor is modified so as to provide a separate subcooling system for the refrigerant, so that efficiency losses due to flashing are reduced. Subcooling occurs when heat exchange is provided between the refrigerant and a heat pumping surface, which is exposed to the standing acoustic wave within the standing wave compressor. A variable capacity and variable discharge pressure for the standing wave compressor is provided. A control circuit simultaneously varies the capacity and discharge pressure in response to changing operating conditions, thereby maintaining the minimum discharge pressure needed for condensation to occur at any time. Thus, the power consumption of the standing wave compressor is reduced and system efficiency is improved.

Application of simplified desorption method to sorption study. (2) Sorption of neptunium (V) on montmorillonite-based mixtures

International Nuclear Information System (INIS)

Kozai, Naofumi; Ohnuki, Toshihiko

2013-01-01

To elucidate the sorption behaviors of radionuclides in multi-mineral systems and the mutual effects of minerals on the sorption, this paper carried out the sorption and desorption experiments of neptunium(V) on montmorillonite-based two-mineral mixtures. The Np sorbed on montmorillonite at pH from 4 to 8 was desorbed with 1M KCl solutions, indicating that the sorption was cation exchange. The Np sorbed on apatite and calcite was nondesorbable with 1M KCl solutions, which is in harmony with the knowledge that Np forms strong complexes with the phosphate groups of apatite and the carbonate groups of calcite. This study utilized these clear distinguishes of the desorption behaviors for examining the two-mineral systems. In montmorillonite-apatite mixtures, the sorption on the montmorillonite was decreased and Np was accumulated on the apatite. In montmorillonite-calcite mixtures, the sorption on the montmorillonite was decreased due to the interference by the calcium and carbonate ions dissolved from calcite while no accumulation of Np to calcite was observed. (author)

Exergetic analysis of refrigeration system of the Pelletron-Linac particle accelerator of the University of Sao Paulo

International Nuclear Information System (INIS)

Oliveira Filho, O.B. de

1993-01-01

The Pelletron-Linac accelerator of the University of Sao Paulo will use the existing electrostatic Pelletron accelerator as an injector for the linear superconducting accelerator (Linac), to increase the acceleration of the particles. The Linac uses a forced flow circulation helium system to promote continuous refrigeration for long periods of time, at temperatures below or equal to 4,9 K. This paper shows the exergetic analysis of the Pelletron-linac refrigerator, identifying the main sources of irreversibilities and evaluating energetic consumption of the system. An exergy-enthalpy diagram for the helium shows the thermodynamic processes that take place in the refrigeration plant and the exergy losses. (author)

Sorption of streptococcus faecium to glass

International Nuclear Information System (INIS)

Oerstavik, D.

1977-01-01

A method has been developed by which to study the sorption of Streptococcus faecium to soda-lime cover glasses. Conditions were chosen to minimize the influence on sorption of bacterial polymer production, passive sorption being studied rather than attachment mediated by metabolic activities. Sorption of S. faecium increased with increasing temperature (to 50degC), time, and cell concentration, but equilibrium apparently was not reached even after incubation for 8 hours or at a cell concentration of 3 x 10 10 per ml. Sorption increased with solute molarity up to 0.1 M concentration of NaCl and KCl, indicating an effect of the electrical double layers on the apposition of cells to the glass surface. Desorption of bacteria could be obtained after multiple washings of the glasses in buffer or by the action of Tween 80, but not if sorbed bacteria were left in distilled water, various salt solutions, urea, or in suspensions of unlabelled bacteria. It was concluded that sorption occurred as a result of chemical interactions between the glass and the cell surface. Tween 80 at a concentration of 1 per cent inhibited sorption to 26 per cent of buffer controls, 2 M urea was less effective, and 1 M NaCl was without effect. It is suggested that hydrophobic interactions may be of importance in the binding of S. faecium to glass. (author)

Nitrate Sorption in an Agricultural Soil Profile

Directory of Open Access Journals (Sweden)

Wissem Hamdi

2013-01-01

Full Text Available Increasing concentrations of in surface water and groundwater can cause ecological and public health effects and has come under increased scrutiny by both environmental scientists and regulatory agencies. For many regions though, including the Sahel of Tunisia, little is known about the sorption capacity of soils. In this project we measured sorption by a profile of an iso-humic soil from Chott Meriem, Tunisia. Soil samples were collected from four soil depths (0–25, 25–60, 60–90, and 90–120 cm on 1 June 2011, and their sorption capacity was determined using batch experiments under laboratory conditions. The effects of contact time, the initial concentration, and the soil-solution ratio on sorption were investigated. In general, the results suggested that was weakly retained by the Chott Meriem soil profile. The quantity of sorption increased with depth, contact time, initial concentration, and soil-solution ratios. To evaluate the sorption capacities of the soil samples at concentrations ranging between 25 and 150 mg L−1 experimental data were fitted to both Freundlich and Langmuir isotherm sorption models. The results indicated that Freundlich model was better for describing sorption in this soil profile.

Two-phase flow in refrigeration systems

CERN Document Server

Gu, Junjie; Gan, Zhongxue

2013-01-01

Two-Phase Flow in Refrigeration Systems presents recent developments from the authors' extensive research programs on two-phase flow in refrigeration systems. This book covers advanced mass and heat transfer and vapor compression refrigeration systems and shows how the performance of an automotive air-conditioning system is affected through results obtained experimentally and theoretically, specifically with consideration of two-phase flow and oil concentration. The book is ideal for university postgraduate students as a textbook, researchers and professors as an academic reference book, and b

Sorption of U(VI) species on hydroxyapatite

International Nuclear Information System (INIS)

Thakur, P.; Moore, R.C.; Choppin, G.R.

2005-01-01

The sorption of uranyl (UO 2 2+ ) cations to hydroxyapatite was studied as a function of the amount of sorbent, ionic strength, U(VI) concentration, pH and temperature. The rate of uranyl sorption on hydroxyapatite decreased with increased uranyl concentrations. The amount sorbed decreased with increased ionic strength and increased with pH to a maximum at 7-8. The sorption data for UO 2 2+ were fitted well by the Freundlich and Dubinin-Radushkevich (D-R) isotherms. The anions Cl - , NO 3 - , SO 4 2- and CH 3 COO - decreased the sorption of uranium on hydroxyapatite while S 2 O 3 2- slightly increased it. The sorbed uranium was desorbed by 0.10 M and 1.00 M solutions of HCl and HNO 3 . The thermodynamic parameters for the sorption of UO 2 2+ were measured at temperatures of 298, 313, 323 and 333 K. The temperature dependence confirmed an endothermic heat of sorption. The activation energy for the sorption process was calculated to be +2.75±0.02 kJ/mol. (orig.)

Model based control of refrigeration systems

Energy Technology Data Exchange (ETDEWEB)

Sloth Larsen, L.F.

2005-11-15

with a distributed control structure, the cross-couplings are not naturally incorporated in the design of the controllers. The disturbances caused by the individual subsystems might be insignificant, however if the effect from all of the subsystems is synchronized it might cause a sever deterioration in the system performance. In the part of the thesis covering dynamical optimization, the main emphasis is laid on analyzing the phenomena of synchronization of hysteresis controlled subsystems. The propose method for desynchronization is based on a model predictive control setup. By formulating a cost function that penalizes the effects of synchronization hard, an optimal control sequence for the subsystems can be computed that desynchronizes the operation. A supermarket's refrigeration system consists of a number of refrigerated display cases located in the supermarkets sales area. The display cases are connected to a central refrigeration system, moreover the temperature control in the display cases is carried out by hysteresis controller. Practice however shows that the display cases have a tendency to synchronize the temperature control. This cause periodically high loads on the central refrigeration system and thereby an increased energy consumption and wear. By studying a nonlinear system model it has been analyzed, which parameter that are important for the synchronization. Applying the proposed method on the nonlinear system model has proved that it is capable of desynchronizing the operation of the display cases. (au)

SORPTION OF Au(III BY Saccharomyces cerevisiae BIOMASS

Directory of Open Access Journals (Sweden)

Amaria Amaria

2010-07-01

Full Text Available Au(III sorption by S. cerevisiae biomass extracted from beer waste industry was investigated. Experimentally, the sorption was conducted in batch method. This research involved five steps: 1 identification the functional groups present in the S. cerevisiae biomass by infrared spectroscopic technique, 2 determination of optimum pH, 3 determination of the sorption capacity and energy, 4 determination of the sorption type by conducting desorption of sorbed Au(III using specific eluents having different desorption capacity such as H2O (van der Waals, KNO3 (ion exchange, HNO3 (hydrogen bond, and tiourea (coordination bond, 5 determination of effective eluents in Au(III desorption by partial desorption of sorbed Au(III using thiourea, NaCN and KI. The remaining Au(III concentrations in filtrate were analyzed using Atomic Absorption Spectrophotometer. The results showed that: 1 Functional groups of S. cerevisiae biomass that involved in the sorption processes were hydroxyl (-OH, carboxylate (-COO- and amine (-NH2, 2 maximum sorption was occurred at pH 4, equal to 98.19% of total sorption, 3 The sorption capacity of biomass was 133.33 mg/g (6.7682E-04 mol/g and was involved sorption energy 23.03 kJ mol-1, 4 Sorption type was dominated by coordination bond, 5 NaCN was effective eluent to strip Au(III close to 100%.   Keywords: sorption, desorption, S. cerevisiae biomass, Au(III

Thermodynamic sorption modelling in support of radioactive waste disposal safety cases - NEA sorption project phase III

International Nuclear Information System (INIS)

2012-01-01

A central safety function of radioactive waste disposal repositories is the prevention or sufficient retardation of radionuclide migration to the biosphere. Performance assessment exercises in various countries, and for a range of disposal scenarios, have demonstrated that one of the most important processes providing this safety function is the sorption of radionuclides along potential migration paths beyond the engineered barriers. Thermodynamic sorption models (TSMs) are key for improving confidence in assumptions made about such radionuclide sorption when preparing a repository's safety case. This report presents guidelines for TSM development as well as their application in repository performance assessments. They will be of particular interest to the sorption modelling community and radionuclide migration modellers in developing safety cases for radioactive waste disposal Contents: 1 - Thermodynamic sorption models and radionuclide migration: Sorption and radionuclide migration; Applications of TSMs in radioactive waste disposal studies; Requirements for a scientifically defensible, calibrated TSM applicable to radioactive waste disposal; Current status of TSMs in radioactive waste management; 2 - Theoretical basis of TSMs and options in model development: Conceptual building blocks of TSMs and integration with aqueous chemistry; The TSM representation of sorption and relationship with Kd values; Theoretical basis of TSMs; Example of TSM for uranyl sorption; Options in TSM development; Illustration of TSM development and effects of modelling choices; Summary: TSMs for constraining Kd values - impact of modelling choices; 3 - Determination of parameters for TSMs: Overview of experimental determination of TSM parameters; Theoretical estimation methods of selected model parameters; Case study: sorption modelling of trivalent lanthanides/actinides on illite; Indicative values for certain TSM parameters; Parameter uncertainty; Illustration of parameter sensitivity

Sorption and mobility of 14C-fenamiphos in Brazilian soils.

Science.gov (United States)

Cáceres, Tanya; Venkateswarlu, Kadiyala

2018-02-02

Although fenamiphos is widely used as an insecticide and nematicide in bowling greens and agriculture, information on its sorption in tropical soils is limited. In this study, mobility, sorption, and desorption dynamics of 14 C-fenamiphos in three contrasting Brazilian soils were examined both in batch and column experiments. Fenamiphos sorption coefficients (K d ) were 2.33, 3.86, and 3.9 L kg -1 for the three soils tested. The insecticide exhibited linear adsorption isotherms in all the three soils, and desorption was in a range of 30-40% during a 72-h period. With its low mobility, fenamiphos did not percolate through the soil profile even after 48 h. However, there is a risk of leaching to water bodies due to runoff because of its high solubility in water. In view of the fact that fenamiphos and its oxidation products are highly toxic to aquatic invertebrates and could affect the soil microbial activities even at low concentrations, the present information is of great importance in risk assessment of fenamiphos in the environment.

Sorption of Heterocyclic Organic Compounds to Multiwalled Carbon Nanotubes.

Science.gov (United States)

Metzelder, Florian; Funck, Matin; Schmidt, Torsten C

2018-01-16

Sorption is an important natural and technical process. Sorption coefficients are typically determined in batch experiments, but this may be challenging for weakly sorbing compounds. An alternative method enabling analysis of those compounds is column chromatography. A column packed with the sorbent is used and sorption data are determined by relating sorbate retention to that of a nonretarded tracer. In this study, column chromatography was applied for the first time to study sorption of previously hardly investigated heterocyclic organic compounds to multiwalled carbon nanotubes (MWCNTs). Sorption data for these compounds are very limited in literature, and weak sorption is expected from predictions. Deuterium oxide was used as nonretarded tracer. Sorption isotherms were well described by the Freundlich model and data showed reasonable agreement with predicted values. Sorption was exothermic and physisorption was observed. H-bonding may contribute to overall sorption, which is supported by reduced sorption with increasing ionic strength due to blocking of functional groups. Lowering pH reduced sorption of ionizable compounds, due to electrostatic repulsion at pH 3 where sorbent as well as sorbates were positively charged. Overall, column chromatography was successfully used to study sorption of heterocyclic compounds to MWCNTs and could be applied for other carbon-based sorbents.

Performance comparison of a refrigerator system using R134a and hydrocarbon refrigerant (HCR134a) with different expansion devices

Science.gov (United States)

Aziz, A.; Izzudin; Mainil, A. K.

2017-09-01

The objective of this study is to compare the performance of refrigerator system using working fluid between R134a refrigerant and HCR134a as hydrocarbon refrigerant for substitution of R134a. The use of capillary tube (CT) 1.5 m with HCR134a showed that slightly better COP than among the others, due to the lower pressure of condenser, conversely thermostatic expansion valve (TEV) showed that better COP than among the others with R134a. COP of CT 1.25 m and CT 1.5 m using HCR134a increase about 42.89% and 18.09% compared to R134a, where the electric current of refrigerator system decrease about 11.63% and 10.98%. However, the COP of HCR134a with CT 2.7 m and TEV were obtained lower than R134a about 16.2% and 17.06% and the use of electric current is higher than R134a about 12.98% and 16.5%. The use of HCR134a provides a higher refrigeration effect than R134a about 66.71%-88.27% for various types of expansion devices. The results confirmed that HCR134a could be an alternative refrigerant for replacement of R134a refrigerant.

REDUCING REFRIGERANT EMISSIONS FROM SUPERMARKET SYSTEMS

Science.gov (United States)

Large refrigeration systems are found in several applications including supermarkets, cold storage warehouses, and industrial processes. The sizes of these systems are a contributing factor to their problems of high refrigerant leak rates because of the thousands of connections, ...

Sorption of nitrate onto amine-crosslinked wheat straw: characteristics, column sorption and desorption properties.

Science.gov (United States)

Xing, Xu; Gao, Bao-Yu; Zhong, Qian-Qian; Yue, Qin-Yan; Li, Qian

2011-02-15

The nitrate removal process was evaluated using a fixed-bed column packed with amine-crosslinked wheat straw (AC-WS). Column sorption and desorption characteristics of nitrate were studied extensively. Solid-state (13)C NMR and zeta potential analysis validated the existence of crosslinked amine groups in AC-WS. Raman shift of the nitrate peaks suggested the electrostatic attraction between the adsorbed ions and positively charged amine sites. The column sorption capacity (q(ed)) of the AC-WS for nitrate was 87.27 mg g(-1) in comparison with the raw WS of 0.57 mg g(-1). Nitrate sorption in column was affected by bed height, influent nitrate concentration, flow rate and pH, and of all these, influent pH demonstrated an essential effect on the performance of the column. In addition, desorption and dynamic elution tests were repeated for several cycles, with high desorption rate and slight losses in its initial column sorption capacity. Copyright © 2010 Elsevier B.V. All rights reserved.

Quantum-Circuit Refrigerator

Science.gov (United States)

MöTtöNen, Mikko; Tan, Kuan Y.; Masuda, Shumpei; Partanen, Matti; Lake, Russell E.; Govenius, Joonas; Silveri, Matti; Grabert, Hermann

Quantum technology holds great potential in providing revolutionizing practical applications. However, fast and precise cooling of the functional quantum degrees of freedom on demand remains a major challenge in many solid-state implementations, such as superconducting circuits. We demonstrate direct cooling of a superconducting resonator mode using voltage-controllable quantum tunneling of electrons in a nanoscale refrigerator. In our first experiments on this type of a quantum-circuit refrigerator, we measure the drop in the mode temperature by electron thermometry at a resistor which is coupled to the resonator mode through ohmic losses. To eliminate unwanted dissipation, we remove the probe resistor and directly observe the power spectrum of the resonator output in agreement with the so-called P(E) theory. We also demonstrate in microwave reflection experiments that the internal quality factor of the resonator can be tuned by orders of magnitude. In the future, our refrigerator can be integrated with different quantum electric devices, potentially enhancing their performance. For example, it may prove useful in the initialization of superconducting quantum bits and in dissipation-assisted quantum annealing. We acknowledge European Research Council Grant SINGLEOUT (278117) and QUESS (681311) for funding.

Solar-Powered Refrigeration System

Science.gov (United States)

Ewert, Michael K. (Inventor); Bergeron, David J., III (Inventor)

2002-01-01

A solar powered vapor compression refrigeration system is made practicable with thermal storage and novel control techniques. In one embodiment, the refrigeration system includes a photovoltaic panel, a variable speed compressor, an insulated enclosure, and a thermal reservoir. The photovoltaic (PV) panel converts sunlight into DC (direct current) electrical power. The DC electrical power drives a compressor that circulates refrigerant through a vapor compression refrigeration loop to extract heat from the insulated enclosure. The thermal reservoir is situated inside the insulated enclosure and includes a phase change material. As heat is extracted from the insulated enclosure, the phase change material is frozen, and thereafter is able to act as a heat sink to maintain the temperature of the insulated enclosure in the absence of sunlight. The conversion of solar power into stored thermal energy is optimized by a compressor control method that effectively maximizes the compressor's usage of available energy. A capacitor is provided to smooth the power voltage and to provide additional current during compressor start-up. A controller monitors the rate of change of the smoothed power voltage to determine if the compressor is operating below or above the available power maximum, and adjusts the compressor speed accordingly. In this manner, the compressor operation is adjusted to convert substantially all available solar power into stored thermal energy.

Solar Powered Refrigeration System

Science.gov (United States)

Ewert, Michael K. (Inventor); Bergeron, David J., III (Inventor)

2002-01-01

A solar powered vapor compression refrigeration system is made practicable with thermal storage and novel control techniques. In one embodiment, the refrigeration system includes a photovoltaic panel, a variable speed compressor, an insulated enclosure, and a thermal reservoir. The photovoltaic (PV) panel converts sunlight into DC (direct current) electrical power. The DC electrical power drives a compressor that circulates refrigerant through a vapor compression refrigeration loop to extract heat from the insulated enclosure. The thermal reservoir is situated inside the insulated enclosure and includes a phase change material. As heat is extracted from the insulated enclosure, the phase change material is frozen, and thereafter is able to act as a heat sink to maintain the temperature of the insulated enclosure in the absence of sunlight. The conversion of solar power into stored thermal energy is optimized by a compressor control method that effectively maximizes the compressor's usage of available energy. A capacitor is provided to smooth the power voltage and to provide additional current during compressor start-up. A controller monitors the rate of change of the smoothed power voltage to determine if the compressor is operating below or above the available power maximum, and adjusts the compressor speed accordingly. In this manner, the compressor operation is adjusted to convert substantially all available solar power into stored thermal energy.

Improvement of a thermoelectric and vapour compression hybrid refrigerator

International Nuclear Information System (INIS)

Astrain, D.; Martínez, A.; Rodríguez, A.

2012-01-01

This paper presents the improvement in the performance of a domestic hybrid refrigerator that combines vapour compression technology for the cooler and freezer compartments, and thermoelectric technology for a new compartment. The heat emitted by the Peltier modules is discharged into the freezer compartment, forming a cascade refrigeration system. This configuration leads to a significant improvement in the coefficient of operation. Thus, the electric power consumption of the modules and the refrigerator decreases by 95% and 20% respectively, with respect to those attained with a cascade refrigeration system connected with the cooler compartment. The optimization process is based on a computational model that simulates the behaviour of the whole refrigerator. Two prototypes have been built and tested. Experimental results indicate that the temperature of the new compartment is easily set up at any value between 0 and −4 °C, the oscillation of this temperature is always lower than 0.4 °C, and the electric power consumption is low enough to include this hybrid refrigerator into energy efficiency class A, according European rules and regulations. - Highlights: ► Optimization of a vapour compression and thermoelectric hybrid refrigerator. ► Two prototypes built and tested. Computational model for the whole refrigerator. ► Electric power consumption of the modules and the refrigerator 95% and 20% lower. ► New compartment refrigerated with thermoelectric technology. ► Inner temperature adjustable from 0 to −4 °C. Oscillations lower than ±0.2 °C.

The climate change implications of manufacturing refrigerants. A calculation of 'production' energy contents of some common refrigerants

International Nuclear Information System (INIS)

Campbell, N.J.; McCulloch, A.

1998-01-01

Total Equivalent Warming Impact (TEWI) analysis has been shown to be a useful aid to quantifying the climate change effect of potential emissions from the operation of systems that involve the use of greenhouse gases and consume energy, so generating CO 2 emissions. It enables these systems to be optimized for minimum global warming impact. In previous studies, the energies required to manufacture the greenhouse gases themselves were not included; by analogy with other chemical manufacturing processes they were assumed to be small in the context of climate change. In the work described here, climate change impacts from the energy used to produce a number of common refrigerant fluids are evaluated. These impacts are compared with the potential impact on global warming from the other components of TEWI: use and disposal of the refrigerants, including direct release into the environment. It is shown that the implications for climate change of the production of traditional refrigerants like ammonia, hydrocarbons or CFC-12 and new refrigerating fluids, such as HFC-134a, are truly insignificant in comparison with other stages of the life cycle of a refrigerator and have no role in TEWI. (author)

Component-wise exergy and energy analysis of vapor compression refrigeration system using mixture of R134a and LPG as refrigerant

Science.gov (United States)

Gill, Jatinder; Singh, Jagdev

2017-11-01

In this work, the experimental examination was carried out using a mixture of R134a and LPG refrigerant (consisting of R134a and LPG in a proportion of 28:72 by weight) as a replacement for R134a in a vapor compression refrigeration system. Exergy and energy tests were carried out at different evaporator and condenser temperatures with controlled environmental conditions. The results showed that the exergy destruction in the compressor, condenser, evaporator, and a capillary tube of the R134a / LPG refrigeration system was found lower by approximately 11.13-3.41%, 2.24-3.43%, 12.02-13.47% and 1.54-5.61% respectively. The compressor exhibits the highest level of destruction, accompanied by a condenser, an evaporator and a capillary tube in refrigeration systems. The refrigeration capacity, COP and power consumption of the compressor of the R134a /LPG refrigeration system were detected higher and lower compared to the R134a refrigeration system by about 7.04-11.41%, 15.1-17.82%, and 3.83-8.08% respectively. Also, the miscibility of R134a and LPG blend with mineral oil discovered good. The R134a and LPG refrigerant mixture proposed in this study perform superior to R134a from component-wise exergy and energy analyses under similar experimental conditions.

Component-wise exergy and energy analysis of vapor compression refrigeration system using mixture of R134a and LPG as refrigerant

Science.gov (United States)

Gill, Jatinder; Singh, Jagdev

2018-05-01

In this work, the experimental examination was carried out using a mixture of R134a and LPG refrigerant (consisting of R134a and LPG in a proportion of 28:72 by weight) as a replacement for R134a in a vapor compression refrigeration system. Exergy and energy tests were carried out at different evaporator and condenser temperatures with controlled environmental conditions. The results showed that the exergy destruction in the compressor, condenser, evaporator, and a capillary tube of the R134a / LPG refrigeration system was found lower by approximately 11.13-3.41%, 2.24-3.43%, 12.02-13.47% and 1.54-5.61% respectively. The compressor exhibits the highest level of destruction, accompanied by a condenser, an evaporator and a capillary tube in refrigeration systems. The refrigeration capacity, COP and power consumption of the compressor of the R134a /LPG refrigeration system were detected higher and lower compared to the R134a refrigeration system by about 7.04-11.41%, 15.1-17.82%, and 3.83-8.08% respectively. Also, the miscibility of R134a and LPG blend with mineral oil discovered good. The R134a and LPG refrigerant mixture proposed in this study perform superior to R134a from component-wise exergy and energy analyses under similar experimental conditions.

Dilution Refrigeration of Multi-Ton Cold Masses

CERN Document Server

Wikus, P; CERN. Geneva

2007-01-01

Dilution refrigeration is the only means to provide continuous cooling at temperatures below 250 mK. Future experiments featuring multi-ton cold masses require a new generation of dilution refrigeration systems, capable of providing a heat sink below 10 mK at cooling powers which exceed the performance of present systems considerably. This thesis presents some advances towards dilution refrigeration of multi-ton masses in this temperature range. A new method using numerical simulation to predict the cooling power of a dilution refrigerator of a given design has been developed in the framework of this thesis project. This method does not only allow to take into account the differences between an actual and an ideal continuous heat exchanger, but also to quantify the impact of an additional heat load on an intermediate section of the dilute stream. In addition, transient behavior can be simulated. The numerical model has been experimentally verified with a dilution refrigeration system which has been designed, ...

Correlation of refrigerant mass flow rate through adiabatic capillary tubes using mixture refrigerant carbondioxide and ethane for low temperature applications

Science.gov (United States)

Nasruddin, Syaka, Darwin R. B.; Alhamid, M. Idrus

2012-06-01

Various binary mixtures of carbon dioxide and hydrocarbons, especially propane or ethane, as alternative natural refrigerants to Chlorofluorocarbons (CFCs) or Hydro fluorocarbons (HFCs) are presented in this paper. Their environmental performance is friendly, with an ozone depletion potential (ODP) of zero and Global-warming potential (GWP) smaller than 20. The capillary tube performance for the alternative refrigerant HFC HCand mixed refrigerants have been widely studied. However, studies that discuss the performance of the capillary tube to a mixture of natural refrigerants, in particular a mixture of azeotrope carbon dioxide and ethane is still undeveloped. A method of empirical correlation to determine the mass flow rate and pipe length has an important role in the design of the capillary tube for industrial refrigeration. Based on the variables that effect the rate of mass flow of refrigerant in the capillary tube, the Buckingham Pi theorem formulated eight non-dimensional parameters to be developed into an empirical equations correlation. Furthermore, non-linear regression analysis used to determine the co-efficiency and exponent of this empirical correlation based on experimental verification of the results database.

Refrigeration systems and applications

CERN Document Server

Dincer, Ibrahim

2010-01-01

Refrigeration Systems and Applications, 2nd edition offers a comprehensive treatise that addresses real-life technical and operational problems, enabling the reader to gain an understanding of the fundamental principles and the practical applications of refrigeration technology. New and unique analysis techniques (including exergy as a potential tool), models, correlations, procedures and applications are covered, and recent developments in the field are included - many of which are taken from the author's own research activities in this area. The book also includes so

Literature survey of heat transfer enhancement techniques in refrigeration applications

Energy Technology Data Exchange (ETDEWEB)

Jensen, M.K.; Shome, B. [Rensselaer Polytechnic Inst., Troy, NY (United States). Dept. of Mechanical Engineering, Aeronautical Engineering and Mechanics

1994-05-01

A survey has been performed of the technical and patent literature on enhanced heat transfer of refrigerants in pool boiling, forced convection evaporation, and condensation. Extensive bibliographies of the technical literature and patents are given. Many passive and active techniques were examined for pure refrigerants, refrigerant-oil mixtures, and refrigerant mixtures. The citations were categorized according to enhancement technique, heat transfer mode, and tube or shell side focus. The effects of the enhancement techniques relative to smooth and/or pure refrigerants were illustrated through the discussion of selected papers. Patented enhancement techniques also are discussed. Enhanced heat transfer has demonstrated significant improvements in performance in many refrigerant applications. However, refrigerant mixtures and refrigerant-oil mixtures have not been studied extensively; no research has been performed with enhanced refrigerant mixtures with oil. Most studies have been of the parametric type; there has been inadequate examination of the fundamental processes governing enhanced refrigerant heat transfer, but some modeling is being done and correlations developed. It is clear that an enhancement technique must be optimized for the refrigerant and operating condition. Fundamental processes governing the heat transfer must be examined if models for enhancement techniques are to be developed; these models could provide the method to optimize a surface. Refrigerant mixtures, with and without oil present, must be studied with enhancement devices; there is too little known to be able to estimate the effects of mixtures (particularly NARMs) with enhanced heat transfer. Other conclusions and recommendations are offered.

Kinetics and reversibility of micropollutant sorption in sludge.

Science.gov (United States)

Barret, Maialen; Carrère, Hélène; Patau, Mathieu; Patureau, Dominique

2011-10-01

The fate of micropollutants throughout wastewater treatment systems is highly dependent on their sorption interactions with sludge matter. In this study, both the sorption and desorption kinetics of polycyclic aromatic hydrocarbons (PAHs) in activated sludge were shown to be very rapid in comparison to biodegradation kinetics. It was concluded that PAH transfer does not limit their biodegradation and that their fate is governed by the sorption/desorption equilibrium state. The effect of contact time between sludge and PAHs was also investigated. It was shown that aging did not influence the sorption/desorption equilibrium although PAH losses during aging suggest that sequestration phenomena had occurred. This implies that for PAH sorption assessment within treatment processes there is no need to include a contact time dimension. As a consequence, thanks to an innovative approach taking into account sorption equilibria and sequestration, this work has demonstrated that studies in the literature which, in main, deal with micropollutant sorption in sewage sludge with only a short contact time can be extrapolated to real systems in which sorption, desorption and aging occur.

Column Chromatography To Obtain Organic Cation Sorption Isotherms.

Science.gov (United States)

Jolin, William C; Sullivan, James; Vasudevan, Dharni; MacKay, Allison A

2016-08-02

Column chromatography was evaluated as a method to obtain organic cation sorption isotherms for environmental solids while using the peak skewness to identify the linear range of the sorption isotherm. Custom packed HPLC columns and standard batch sorption techniques were used to intercompare sorption isotherms and solid-water sorption coefficients (Kd) for four organic cations (benzylamine, 2,4-dichlorobenzylamine, phenyltrimethylammonium, oxytetracycline) with two aluminosilicate clay minerals and one soil. A comparison of Freundlich isotherm parameters revealed isotherm linearity or nonlinearity was not significantly different between column chromatography and traditional batch experiments. Importantly, skewness (a metric of eluting peak symmetry) analysis of eluting peaks can establish isotherm linearity, thereby enabling a less labor intensive means to generate the extensive data sets of linear Kd values required for the development of predictive sorption models. Our findings clearly show that column chromatography can reproduce sorption measures from conventional batch experiments with the benefit of lower labor-intensity, faster analysis times, and allow for consistent sorption measures across laboratories with distinct chromatography instrumentation.

Control Methods for Energy Management of Refrigeration Systems

DEFF Research Database (Denmark)

Shafiei, Seyed Ehsan

is decreased as the method does not need an explicit model of the system and, at the same time, the desired load following performance is attained. Recent research findings indicate that the refrigeration system commonly employed in food transportation can account for 40% of the total greenhouse gas emissions...... from the corresponding vehicle engines. Finally, the problem of optimization of a hybrid transport refrigeration system is addressed here. The hybrid refrigeration system is made by the integration of conventional refrigeration technology with thermal energy storage devices....

Prediction of thermodynamic properties of refrigerants using data mining

International Nuclear Information System (INIS)

Kuecueksille, Ecir Ugur; Selbas, Resat; Sencan, Arzu

2011-01-01

The analysis of vapor compression refrigeration systems requires the availability of simple and efficient mathematical formulations for the determination of thermodynamic properties of refrigerants. The aim of this study is to determine thermodynamic properties as enthalpy, entropy and specific volume of alternative refrigerants using data mining method. Alternative refrigerants used in the study are R134a, R404a, R407c and R410a. The results obtained from data mining have been compared to actual data from the literature. The study shows that the data mining methodology is successfully applicable to determine enthalpy, entropy and specific volume values for any temperature and pressure of refrigerants. Therefore, computation time reduces and simulation of vapor compression refrigeration systems is fairly facilitated.

Exergy analysis of refrigerators for large scale cooling systems

Energy Technology Data Exchange (ETDEWEB)

Loehlein, K [Sulzer Cryogenics, Winterthur (Switzerland); Fukano, T [Nippon Sanso Corp., Kawasaki (Japan)

1993-01-01

Facilities with superconducting magnets require cooling capacity at different temperature levels and of different types (refrigeration or liquefaction). The bigger the demand for refrigeration, the more investment for improved efficiency of the refrigeration plant is justified and desired. Refrigeration cycles are built with discrete components like expansion turbines, cold compressors, etc. Therefore the exergetic efficiency for producing refrigeration on a distinct temperature level is significantly dependent on the 'thermodynamic arrangement' of these components. Among a variety of possibilities, limited by the range of applicability of the components, one has to choose the best design for higher efficiency on every level. Some influences are being quantified and aspects are given for a optimal integration of the refrigerator into the whole cooling system. (orig.).

46 CFR 154.1720 - Indirect refrigeration.

Science.gov (United States)

2010-10-01

... Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) CERTAIN BULK DANGEROUS CARGOES SAFETY STANDARDS FOR SELF-PROPELLED VESSELS CARRYING BULK LIQUEFIED GASES Special Design and Operating Requirements § 154.1720 Indirect refrigeration. A refrigeration system that is used to cool acetaldehyde, ethylene...

Simulation of the Energy Saver refrigeration system

International Nuclear Information System (INIS)

Barton, H.R. Jr.; Nicholls, J.E.; Mulholland, G.T.

1981-10-01

The helium refrigeration for the Energy Saver is supplied by a Central Helium Liquefier and 24 Satellite Refrigerators installed over a 1-1/4 square mile area. An interactive, software simulator has been developed to calculate the refrigeration available from the cryogenic system over a wide range of operating conditions. The refrigeration system simulator incorporates models of the components which have been developed to quantitatively describe changes in system performance. The simulator output is presented in a real-time display which has been used to search for the optimal operating conditions of the Satellite-Central system, to examine the effect of an extended range of operating parameters and to identify equipment modifications which would improve the system performance

Basics of Low-temperature Refrigeration

CERN Document Server

Alekseev, A.

2014-07-17

This chapter gives an overview of the principles of low temperature refrigeration and the thermodynamics behind it. Basic cryogenic processes - Joule-Thomoson process, Brayton process as well as Claude process - are described and compared. A typical helium laboratory refrigerator based on Claude process is used as a typical example of a low-temperature refrigeration system. A description of the hardware components for helium liquefaction is an important part of this paper, because the design of the main hardware components (compressors, turbines, heat exchangers, pumps, adsorbers, etc.) provides the input for cost calculation, as well as enables to estimate the reliability of the plant and the maintenance expenses. All these numbers are necessary to calculate the economics of a low temperature application.

Basics of Low-temperature Refrigeration

Energy Technology Data Exchange (ETDEWEB)

Alekseev, A [Linde AG, Munich (Germany)

2014-07-01

This chapter gives an overview of the principles of low temperature refrigeration and the thermodynamics behind it. Basic cryogenic processes - Joule-Thomoson process, Brayton process as well as Claude process - are described and compared. A typical helium laboratory refrigerator based on Claude process is used as a typical example of a low-temperature refrigeration system. A description of the hardware components for helium liquefaction is an important part of this paper, because the design of the main hardware components (compressors, turbines, heat exchangers, pumps, adsorbers, etc.) provides the input for cost calculation, as well as enables to estimate the reliability of the plant and the maintenance expenses. All these numbers are necessary to calculate the economics of a low temperature application.

Sorption Energy Maps of Clay Mineral Surfaces

International Nuclear Information System (INIS)

Cygan, Randall T.; Kirkpatrick, R. James

1999-01-01

A molecular-level understanding of mineral-water interactions is critical for the evaluation and prediction of the sorption properties of clay minerals that may be used in various chemical and radioactive waste disposal methods. Molecular models of metal sorption incorporate empirical energy force fields, based on molecular orbital calculations and spectroscopic data, that account for Coulombic, van der Waals attractive, and short-range repulsive energies. The summation of the non-bonded energy terms at equally-spaced grid points surrounding a mineral substrate provides a three dimensional potential energy grid. The energy map can be used to determine the optimal sorption sites of metal ions on the exposed surfaces of the mineral. By using this approach, we have evaluated the crystallographic and compositional control of metal sorption on the surfaces of kaolinite and illite. Estimates of the relative sorption energy and most stable sorption sites are derived based on a rigid ion approximation

Development of a Self-Consistent Model of Plutonium Sorption: Quantification of Sorption Enthalpy and Ligand-Promoted Dissolution

Energy Technology Data Exchange (ETDEWEB)

Powell, Brian [Clemson Univ., SC (United States); Kaplan, Daniel I [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Arai, Yuji [Univ. of Illinois, Urbana-Champaign, IL (United States); Becker, Udo [Univ. of Michigan, Ann Arbor, MI (United States); Ewing, Rod [Stanford Univ., CA (United States)

2016-12-29

This university lead SBR project is a collaboration lead by Dr. Brian Powell (Clemson University) with co-principal investigators Dan Kaplan (Savannah River National Laboratory), Yuji Arai (presently at the University of Illinois), Udo Becker (U of Michigan) and Rod Ewing (presently at Stanford University). Hypothesis: The underlying hypothesis of this work is that strong interactions of plutonium with mineral surfaces are due to formation of inner sphere complexes with a limited number of high-energy surface sites, which results in sorption hysteresis where Pu(IV) is the predominant sorbed oxidation state. The energetic favorability of the Pu(IV) surface complex is strongly influenced by positive sorption entropies, which are mechanistically driven by displacement of solvating water molecules from the actinide and mineral surface during sorption. Objectives: The overarching objective of this work is to examine Pu(IV) and Pu(V) sorption to pure metal (oxyhydr)oxide minerals and sediments using variable temperature batch sorption, X-ray absorption spectroscopy, electron microscopy, and quantum-mechanical and empirical-potential calculations. The data will be compiled into a self-consistent surface complexation model. The novelty of this effort lies largely in the manner the information from these measurements and calculations will be combined into a model that will be used to evaluate the thermodynamics of plutonium sorption reactions as well as predict sorption of plutonium to sediments from DOE sites using a component additivity approach.

Distribution and survival of Vibrio vulnificus genotypes in postharvest Gulf Coast (USA) oysters under refrigeration.

Science.gov (United States)

Wood, R R; Arias, C R

2012-07-01

  The effect of refrigeration on the seafood-borne pathogen Vibrio vulnificus was investigated in terms of genotype selection and persistence in refrigerated oysters.   Naturally occurring numbers of V. vulnificus in oysters from two different locations were compared during a 2-week period under refrigeration conditions. At different time points, V. vulnificus isolates were recovered from oysters and ascribed to 16S rRNA gene type A, B or AB using restriction fragment length polymorphism. Initial V. vulnificus numbers were higher than 10(4) most probable number (MPN) g(-1) and remained unchanged throughout the duration of the study. 16S rRNA gene type B isolates accounted for 53% of the isolates recovered. Amplified fragment length polymorphism analysis confirmed the high genetic variability previously observed within this species but revealed the presence of two main genetic groups within the species that matched 16S rRNA gene ascription.   Vibrio vulnificus numbers in oysters did not significantly declined over the shelf life of the product and refrigeration did not select for specific V. vulnificus types.   The prevalence of V. vulnificus 16S rRNA gene type B in oysters was higher than previously reported from the same geographic area and was not significantly reduced during the storage period. Vibrio vulnificus is divided into two clear genotypes, regardless of the genetic marker used. © 2012 The Authors. Journal of Applied Microbiology © 2012 The Society for Applied Microbiology.

Evaluation of Virtual Refrigerant Mass Flow Sensors

OpenAIRE

Kim, Woohyun; Braun, James E.

2012-01-01

Refrigerant mass flow rate is an important measurement for monitoring equipment performance and enabling fault detection and diagnostics. However, a traditional mass flow meter is expensive to purchase and install. A virtual refrigerant mass flow sensor (VRMF) uses a mathematical model to estimate flow rate using low-cost measurements and can potentially be implemented at low cost. This study evaluates three VRMFs for estimating refrigerant mass flow rate. The first model uses a compressor ma...

Energy consumption of small refrigerators - Information leaflet; Merkblatt Kleinkuehlschrank

Energy Technology Data Exchange (ETDEWEB)

NONE

2009-07-01

In this leaflet published by the Swiss Federal Office of Energy (SFOE), the energy consumption of small refrigerators with a capacity of less than 100 litres is reported on. Such small refrigerators are often used in hotel rooms or in campers. It is noted that, in comparison, a typical, 150 litre class A++ domestic refrigerator uses only a fraction of the amount of energy used by such small refrigerators. The results of measurements made according to EN 153 and ISO 15502 norms are discussed. Recommendations are made on the purchase and operation of these small refrigerators.

Compatibility of refrigerants and lubricants with elastomers. Final report

Energy Technology Data Exchange (ETDEWEB)

Hamed, G.R.; Seiple, R.H.; Taikum, Orawan

1994-01-01

The information contained in this report is designed to assist the air-conditioning and refrigeration industry in the selection of suitable elastomeric gasket and seal materials that will prove useful in various refrigerant and refrigeration lubricant environments. In part I of the program the swell behavior in the test fluids has been determined using weight and in situ diameter measurements for the refrigerants and weight, diameter and thickness measurements for the lubricants. Weight and diameter measurements are repeated after 2 and 24 hours for samples removed fro the refrigerant test fluids and 24 hours after removal from the lubricants. Part II of the testing program includes the evaluation of tensile strength, hardness, weight, and dimensional changes after immersion aging in refrigerant/lubricant mixtures of selected elastomer formulations at elevated temperature and pressure.

Sorption of strontium by magnetically modified yeast cells

International Nuclear Information System (INIS)

Hu Yantao; Ji Yanqin; Tian Qing; Shao Xianzhang; Shi Jianhe; Ivo Safarik; Zhang Shengdong; Li Jinying

2008-01-01

Magnetically modified fodder's yeast (Kluyveromyces fragilis) cells using water based magnetic fluid, were characterized by scanning electron microscopy (SEM) and Vibrating Sample Magnetometer (VSM). The sorption-desorption properties of Sr 2+ by these yeast cells from nitrate salt of Sr 2+ were studied. The results demonstrated that the Sr 2+ sorption volume by these cells enhanced with increasing pH and reached a plateau between pH 4.0 and 7.0. A minor effect by temperature was observed. The sorption volumes are 19.5 mg/g and 53.5 mg/g from 10 ppm and 40 ppm Sr 2+ solution respectively within 20 min. The sorption of Sr 2+ in these cells can be desorbed under 0.1 mol/L HNO 3 solution. The maximum Sr 2+ sorption volume is 96.7 mg/g at 20℃. The sorption characteristic fits Langmuir model well with 140.8 mg/g calculated maximum sorption volume by these yeast cells. (authors)

Integrated sorption and diffusion model for bentonite. Part 1. Clay-water interaction and sorption modeling in dispersed systems

International Nuclear Information System (INIS)

Tachi, Yukio; Suyama, Tadahiro; Ochs, Michael

2014-01-01

To predict the long-term migration of radionuclides (RNs) under variable conditions within the framework of safety analyses for geological disposal, thermodynamic sorption models are very powerful tools. The integrated sorption and diffusion (ISD) model for compacted bentonite was developed to achieve a consistent combination of clay–water interaction, sorption, and diffusion models. The basic premise considered in the ISD model was to consistently use the same simple surface model design and parameters for describing RNs sorption/diffusion as well as clay surface and porewater chemistry. A simple 1-site non-electrostatic surface complexation model in combination with a 1-site ion exchange model was selected to keep sorption model characteristics relatively robust for compacted systems. Fundamental parameters for the proposed model were evaluated from surface titration data for purified montmorillonite. The resulting basic model was then parameterized on the basis of selected published sorption data-sets for Np(V), Am(III), and U(VI) in dispersed systems, which cover a range of key geochemical conditions such as pH, ionic strength, and carbonate concentration. The sorption trends for these RNs can be quantitatively described by the model considering a full suite of surface species including hydrolytic and carbonate species. The application of these models to the description of diffusive-sorptive transport in compacted bentonites is presented in Part 2. (author)

A rotary permanent magnet magnetic refrigerator based on AMR cycle

International Nuclear Information System (INIS)

Aprea, C.; Cardillo, G.; Greco, A.; Maiorino, A.; Masselli, C.

2016-01-01

Magnetic refrigeration is an emerging, environment-friendly technology based on a magnetic solid that acts as a refrigerant by magneto-caloric effect (MCE). The reference cycle for magnetic refrigeration is AMR (Active Magnetic Regenerative refrigeration). In order to demonstrate the potential of magnetic refrigeration to provide useful cooling in the near room temperature range, a novel Rotary Permanent Magnet Magnetic Refrigerator (RPMMR) is described in this paper. Gadolinium has been selected as magnetic refrigerant and demineralized water has been employed as regenerating fluid. The total mass of gadolinium (1.20 kg), shaped as packed bed spheres, is housed in 8 regenerators. A magnetic system, based on a double U configuration of permanent magnets, provides a magnetic flux density of 1.25 T with an air gap of 43 mm. A rotary vane pump forces the regenerating fluid through the regenerators. The operational principle of the magnetic refrigerator and initial experimental results are reported and analyzed.

Sorption behavior of cesium onto bentonite colloid

International Nuclear Information System (INIS)

Iijima, Kazuki; Masuda, Tsuguya; Tomura, Tsutomu

2004-01-01

It is considered that bentonite colloid might be generated from bentonite which will be used as buffer material in geological disposal system, and can facilitate the migration of radionuclides by means of sorption. In order to examine this characteristic, sorption and desorption experiments of Cs onto bentonite colloid were carried out to obtain its distribution coefficient (Kd) and information on the reversibility of its sorption. In addition, particle size distribution and shape of colloid were investigated and their effect on the sorption behavior was discussed. Kds for Cs were around 20 m 3 /kg for sorption and 30 m 3 /kg for desorption, in which sorbed Cs was desorbed by 8.4x10 -4 mol/l of NaCl solution. These values did not show any dependencies on Cs concentration and duration of sorption and desorption. The first 20% of sorbed Cs was desorbed reversibly at least. Most of colloidal particles were larger than 200 nm and TEM micrographs showed they had only several sheets of the clay crystal. Obtained Kds for colloidal bentonite were larger than those for powdered bentonite. This can be caused by difference of competing ions in the solution, characteristics of contained smectite, or sorption site density. (author)

Sorption of fission nuclides on model milk components. II. Sorption of radiostrontium on hydroxyapatite in milk and whey

International Nuclear Information System (INIS)

Rosskopfova, O.; Kopunec, R.; Matel, L.; Macasek, F.

1999-01-01

In this work the whey was chosen as a model solution of liquid phase for sorption study of strontium on hydroxyapatite. The whey was obtained using two methods - ultracentrifugation and precipitation of casein. The sorption was studied at a different pH and at a different concentration of calcium. The sorption of strontium on hydroxyapatite from milk was studied, too. (authors)

Coupling of the electrocaloric and electromechanical effects for solid-state refrigeration

Science.gov (United States)

Bradeško, A.; Juričić, Äń.; Santo Zarnik, M.; Malič, B.; Kutnjak, Z.; Rojac, T.

2016-10-01

Electrocaloric (EC) materials have shown the potential to replace some of the technologies in current commercial refrigeration systems. The key problem when fabricating an efficient EC refrigerator is the small adiabatic temperature change that current bulk materials can achieve. Therefore, such a solid-state EC refrigerator should be engineered to enhance the EC temperature change by rectifying the induced EC heat flow. Here, we present a numerical study of a device that couples the EC and electromechanical (EM) effects in a single active material. The device consists of several elements made from a functional material with coupled EC and EM properties, allowing the elements to bend and change their temperature with the application of an electric field. The periodic excitation of these elements results in a temperature span across the device. By assuming heat exchange with the environment and a low thermal contact resistivity between the elements, we show that a device with 15 elements and an EC effect of 1.2 K achieves a temperature span between the hot and cold sides of the device equal to 12.6 K. Since the temperature span can be controlled by the number of elements in the device, the results suggest that in combination with the so-called "giant" EC effect (ΔTEC ≥ 10 K), a very large temperature span would be possible. The results of this work should motivate the development of efficient EC refrigeration systems based on a coupling of the EC and EM effects.

Oskarshamn site investigation. Batch experiments of I, Cs, Sr, Ni, Eu, U and Np sorption onto soil from the Laxemar area

International Nuclear Information System (INIS)

Holgersson, Stellan

2009-04-01

Soil and groundwater samples from the Laxemar area have been collected and characterised, as have previously been reported. Batch experiments with sorption of radiotracers of I, Cs, Sr, Ni, Eu, U and Np have been made with eight selected soil samples and one natural groundwater. The solid/liquid ratio in the experiments was 1/48 and sampling were made at 3 hours, 1 day, 7 days, 14 days, 40 days and finally 130 days. Phase separation was made by centrifugation field > 20 kG. Experiments were made in an inert-gas glove-box (O 2 a (m) that increase with time, but the trend is a levelling out to limiting values. Iodine sorption is generally below the lower detection limit and very few data could be collected for this tracer. Eu generally shows the strongest sorption and some measurements at the later samplings are above the upper detection limit. Results from the batch experiments with peat and natural groundwater at 130 days give R a values that ranges from 5x10 -5 (Sr) to 3x10 -4 m (Cs). The order of increasing sorption is: Sr, Ni, Np, Eu, U and Cs. For synthetic groundwater Eu and U sorption is stronger, at least initially, compared with the natural groundwater, but for Cs the sorption is weaker over the whole sampling period. Results from the batch experiments with gyttja and natural groundwater at 130 days give R a values that ranges from 3x10 -5 (Sr) to 1x10 -2 m (Eu). The order of increasing sorption is: Sr, Cs, U, Ni, Np and Eu. For synthetic groundwater the sorption of U is stronger and comparable with Eu. Results from the batch experiments with clay gyttja, type I and natural groundwater at 130 days give R a values that ranges from 1x10 -5 (Sr) to > 1x10 -3 m (Eu). The order of increasing sorption is: Sr, Cs, Ni, U, Np and Eu. For synthetic groundwater the sorption of U is stronger, at least initially, comparable with Eu. For Np, on the other hand, the sorption is weaker and comparable with Sr over the whole sampling period. Results from the batch experiments

Sorption of cesium in intact rock

International Nuclear Information System (INIS)

Puukko, E.

2014-04-01

The mass distribution coefficient K d is used in performance assessment (PA) to describe sorption of a radionuclide on rock. The R d is determined using crushed rock which causes uncertainty in converting the R d values to K d values for intact rock. This work describes a method to determine the equilibrium of sorption on intact rock. The rock types of the planned Olkiluoto waste disposal site were T-series mica gneiss (T-MGN), T-series tonalite granodiorite granite gneiss (T-TGG), P-series tonalite granodiorite granite gneiss (P-TGG) and pegmatitic granite (PGR). These rocks contain different amount of biotite which is the main sorbing mineral. The sorption of cesium on intact rock slices was studied by applying an electrical field to speed up migration of cesium into the rock. Cesium is in the solution as a noncomplex cation Cs + and it is sorbed by ion exchange. The tracer used in the experiments was 134 Cs. The experimental sorption on the intact rock is compared with values calculated using the in house cation exchange sorption model (HYRL model) in PHREEQC program. The observed sorption on T-MGN and T-TGG rocks was close to the calculated values. Two PGR samples were from a depth of 70 m and three samples were from a depth of 150 m. Cesium sorbed more than predicted on the two 70 m PGR samples. The sorption of Cs on the three 150 m PGR samples was small which was consistent with the calculations. The pegmatitic granite PGR has the smallest content of biotite of the four rock types. In the case of P-TGG rock the observed values of sorption were only half of the calculated values. Two kind of slices were cut from P-TGG drill core. The slices were against and to the direction of the foliation of the biotite rims. The sorption of cesium on P-TGG rock was same in both cases. The results indicated that there was no effect of the directions of the electric field and the foliation of biotite in the P-TGG rock. (orig.)

The use of instrumental neutron activation analysis method in bio-sorption determination

International Nuclear Information System (INIS)

Khamidova, Kh.M.; Mutavalieva, Z.S.; Muchamedshina, N.M.; Mirzagatova, A.A.

2005-01-01

Full text: Recently, much attention is paid to the research and development of effective metal remediation methods. In industry, for the removal of metals from the industrial solutions and wastes, the expensive ion-exchange resin method of metal sorption is used today. The microbiological methods are much less expensive, are available and provide its application in natural conditions. The search for molybdenum bio sorbent was performed amongst Actinomyces strains. The 18 of Streptomyces strains were used. The data showed that all investigated strains uptake the molybdenum from the solution in various degrees. The molybdenum determination was performed using neutron activation analysis technique. In a nuclear reactor, the samples were treated with a steady flow of neutrons (5.1·10 13 ) n·cm -2 sec -1 in 20 hours. The samples were stored for 6-7 days before analysis. The Actinomyces biomass uptake capacity was up to 94.5 %. The 8 cultures have the most high uptake capacity that varied from 87.4 to 94.5 %. Streptomyces sp. 39 and Streptomyces sp.32 have the lowest bio-sorption capacity amongst studied strains, which was 46.6% and 40 % respectively, whereas the bio sorption capacity of other cultures varied from 55.8 to 64.1%. The influence of some physical and chemical parameters (culture age, pH, temperature) on molybdenum bio-sorption was studied. Data showed that the change in pH, temperature and cultivation period lead to the increase of bio-sorption capacity

Fault detection and diagnosis for refrigerator from compressor sensor

Science.gov (United States)

Keres, Stephen L.; Gomes, Alberto Regio; Litch, Andrew D.

2016-12-06

A refrigerator, a sealed refrigerant system, and method are provided where the refrigerator includes at least a refrigerated compartment and a sealed refrigerant system including an evaporator, a compressor, a condenser, a controller, an evaporator fan, and a condenser fan. The method includes monitoring a frequency of the compressor, and identifying a fault condition in the at least one component of the refrigerant sealed system in response to the compressor frequency. The method may further comprise calculating a compressor frequency rate based upon the rate of change of the compressor frequency, wherein a fault in the condenser fan is identified if the compressor frequency rate is positive and exceeds a condenser fan fault threshold rate, and wherein a fault in the evaporator fan is identified if the compressor frequency rate is negative and exceeds an evaporator fan fault threshold rate.

Kinetic studies on phosphorus sorption by selected soil amendments for septic tank effluent renovation.

Science.gov (United States)

Cheung, K C; Venkitachalam, T H

2006-01-01

A systematic kinetic study of phosphorus (P) sorption by various materials in the soil infiltration system of septic tanks was undertaken by following the time course of P sorption by sorbents in contact with various P solutions over periods up to 360 days. Uptake of P seemed to consist of two distinct stages. Initial uptake was very rapid and this phase was completed in 4 days or less. A slower removal stage followed for some materials over many months. Phosphorus sorption during the fast reaction stage appeared to be associated with the soluble Ca content of the materials. The fast reaction of calcareous materials accounted for the bulk (>70%) of the total P removed. Merribrook loamy sand exhibited the highest proportion of P sorption during the slow phase. It should be noted, however, that for solution P concentrations in the range found in typical effluents (approximately 20 mg L(-1)) the fast reaction phase seemed to be responsible for virtually all P removed. None of the six kinetic formulae examined possessed the sophistication and detail needed to portray accurately the time course of P sorption for all the sorbents investigated. The Elovich equation and the kinetic modification of the Freundlich isotherm expression appeared to provide a reasonable fit of the experimental data.

Development of JAEA sorption database (JAEA-SDB). Update of sorption/QA data in FY2015

International Nuclear Information System (INIS)

Tachi, Yukio; Suyama, Tadahiro

2016-03-01

Sorption and diffusion of radionuclides in buffer materials (bentonite) and rocks are the key processes in the safe geological disposal of radioactive waste, because migration of radionuclides in these barrier materials is expected to be diffusion-controlled and retarded by sorption processes. It is therefore necessary to understand the sorption and diffusion processes and develop databases compiling reliable data and mechanistic/predictive models, so that reliable parameters can be set under a variety of geochemical conditions relevant to performance assessment (PA). For this purpose, Japan Atomic Energy Agency (JAEA) has developed databases of sorption and diffusion parameters in bentonites and rocks. These sorption and diffusion databases (SDB/DDB) were firstly developed as an important basis for the H12 PA of high-level radioactive waste disposal, and have been provided through the Web. JAEA has been continuing to improve and update the SDB/DDB in view of potential future data needs, focusing on assuring the desired quality level and testing the usefulness of the databases for possible applications to PA-related parameter setting. The present report focuses on improving and updating of the sorption database (JAEA-SDB) as basis of integrated approach for PA-related K d setting and mechanistic sorption model development. This includes an overview of database structure, contents and functions including additional data evaluation function focusing on statistical data evaluation and grouping of data related to potential perturbations. K d data and their QA results are updated by focusing our recent activities on the K d setting and mechanistic model development. As a result, 11,206 K d data from 83 references were added, total number of K d values in the JAEA-SDB reached about 58,000. The QA/classified K d data reached about 60% for all K d data in JAEA-SDB. The updated JAEA-SDB is expected to make it possible to obtain quick overview of the available data, and to

Long-term studies on the leachability of cemented and non-cemented iodine-129 loaded sorption material

International Nuclear Information System (INIS)

Kaempffer, R.; Furrer, J.

1989-01-01

Leaching tests on the load AC 6120 iodine sorption material (12 wt.% Ag) in water and salt brines were performed over a rather long period of time to allow better judgement of the behavior of radioactive waste disposed of in a salt dome. The utilization of capacity of the loaded iodine sorption material from the Karlsruhe reprocessing plant (WAK) was 95% related to the amount of silver added. The result of the stationary leaching tests has been a leaching rate of the material not embedded in cement of < 0.1%, whereas the leaching rate of the iodine sorption material embedded in cement has been < 0.01% of the total iodine-129 inventory. After addition of carbon steel to the sorption material embedded in cement the same leaching rates were measured as for material not embedded in cement. The addition of stainless steel exerted but little influence on the leaching rate. (orig.)

Energy density and storage capacity cost comparison of conceptual solid and liquid sorption seasonal heat storage systems for low-temperature space heating

NARCIS (Netherlands)

Scapino, L.; Zondag, H.A.; Van Bael, J.; Diriken, J.; Rindt, C.C.M.

Sorption heat storage can potentially store thermal energy for long time periods with a higher energy density compared to conventional storage technologies. A performance comparison in terms of energy density and storage capacity costs of different sorption system concepts used for seasonal heat

Performance Analysis of Multipurpose Refrigeration System (MRS on Fishing Vessel

Directory of Open Access Journals (Sweden)

Ust Y.

2016-04-01

Full Text Available The use of efficient refrigerator/freezers helps considerably to reduce the amount of the emitted greenhouse gas. A two-circuit refrigerator-freezer cycle (RF reveals a higher energy saving potential than a conventional cycle with a single loop of serial evaporators, owing to pressure drop in each evaporator during refrigeration operation and low compression ratio. Therefore, several industrial applications and fish storage systems have been utilized by using multipurpose refrigeration cycle. That is why a theoretical performance analysis based on the exergetic performance coefficient, coefficient of performance (COP, exergy efficiency and exergy destruction ratio criteria, has been carried out for a multipurpose refrigeration system by using different refrigerants in serial and parallel operation conditions. The exergetic performance coefficient criterion is defined as the ratio of exergy output to the total exergy destruction rate (or loss rate of availability. According to the results of the study, the refrigerant R32 shows the best performance in terms of exergetic performance coefficient, COP, exergy efficiency, and exergy destruction ratio from among the other refrigerants (R1234yf, R1234ze, R404A, R407C, R410A, R143A and R502. The effects of the condenser, freezer-evaporator and refrigerator-evaporator temperatures on the exergetic performance coefficient, COP, exergy efficiency and exergy destruction ratios have been fully analyzed for the refrigerant R32.

Iodine sorption by microwave irradiated hydrotalcites

Energy Technology Data Exchange (ETDEWEB)

Paredes, S.P. [Universidad Autonoma de Puebla, Facultad de Ciencias Quimicas, C.P. 72570, Puebla, Pue (Mexico); Instituto Politecnico Nacional, ESIQIE, C.P. 07738, Mexico, D.F. (Mexico); Fetter, G. [Universidad Autonoma de Puebla, Facultad de Ciencias Quimicas, C.P. 72570, Puebla, Pue (Mexico)]. E-mail: geolarfetter@yahoo.com.mx; Bosch, P. [Universidad Nacional Autonoma de Mexico, Instituto de Investigaciones en Materiales, C.P. 04510, Mexico, D.F. (Mexico); Bulbulian, S. [Instituto Nacional de Investigaciones Nucleares, A.P. 18-1027, C.P. 11801, Mexico, D.F. (Mexico)

2006-12-15

Mg-Al hydrotalcite-like compounds (HT) were prepared by the microwave method on the one hand with ethoxide-acetylacetonate and on the other with acetylacetonate as precursors. They presented a maximum sorption capacity of 2.179 and 1.517 meq of {sup 131}I{sup -}/g of hydrotalcite respectively. When the hydrotalcites were calcined and rehydrated in a {sup 131}I{sup -} solution, iodine sorption decreased in both samples to 1.515 and 1.446, respectively. The corresponding value for nitrated hydrotalcite which was prepared by the conventional method for comparison purposes, was 0.570. The radionuclide content in hydrotalcites was determined by {gamma}-spectrometry. {sup 131}I{sup -} sorption is dependent on two main parameters: one is the type of the interlayer organic material and the second the surface area. It was found that hydrotalcites prepared with ethoxide-acetylacetonate were better sorbents for {sup 131}I{sup -} than those with acetylacetonate. Still, if the specific surface area increased, {sup 131}I{sup -}sorption increased as well; nitrated HT resulted in low specific surface area and a low sorption capacity. It is, therefore, concluded that organic residues present in the samples prepared by the microwave method favor the sorption of radioactive anions, in particular {sup 131}I{sup -} if compared with nitrated and/or carbonate interlayered hydrotalcites.

Effect of gamma irradiation on refrigerator storage of peach fruits

International Nuclear Information System (INIS)

Kalinov, V.

1985-01-01

Peach fruits of cvs. Halle and Elberta were gamma irradiated by 0, 2.0, 2.5 and 3.0 kGy and stored in the usual way (20-25 grad C) or in refrigerator (5 and 0 grad C). The rate of mould decay, reduction in market quality and complex evaluation of the fruits at the time of storage were investigated. Linear regression correlations between the percentage of decay and the time of storage were estimated by probit-logarithmic transformation of the percentage of the decayed fruits. On that basis were assess the probable terms to reach 5% decay (permissible period of storage) and 10% decay. The criteria of quality and taste evaluation of the fruits for these periods were determined. The irradiation of peach fruits with 2.5 and 3.0 kGy prolonged 3 to 5 times the period free of decay (up to 5%) in the case of normal storage conditions as compared to the control (no irradiation). The sharp reduction in quality and the sensorial evaluation for these periods did not justify irradiation in case of usual storage conditions. Irradiation with the same rates in case of refrigeration storage proved a useful supplementary factor prolonging the periods before appearance of decay up to 17 days (i.e. 42% as compared to the control) and the permissible period of storage up to 25 days (25% more than the control). These results were obtained at a dose of 2.5 kGy for cv. Halle fruits, at dose 3.0 kGy for cv. Elberta fruits and at storage temperature of 0 grad C. For the periods up to 5% decay (25 to 26 days) the criteria of quality and the complex evaluation remained above the permissible level. Longer storage was not advisable because physiological damage of the fruit was evident

A feasibility analysis of replacing the standard ammonia refrigeration device with the cascade NH3/CO2 refrigeration device in the food industry

Directory of Open Access Journals (Sweden)

Jankovich Dennis

2015-01-01

Full Text Available The thermodynamic analysis demonstrates the feasibility of replacing the standard ammonia refrigeration device with the cascade NH3/CO2 refrigeration device in the food industry. The main reason for replacement is to reduce the total amount of ammonia in spaces like deep-freezing chambers, daily chambers, working rooms and technical passageways. An ammonia-contaminated area is hazardous to human health and the safety of food products. Therefore the preferred reduced amount of ammonia is accumulated in the Central Refrigeration Engine Room, where the cascade NH3/CO2 device is installed as well. Furthermore, the analysis discusses and compares two left Carnot¢s refrigeration cycles, one for the standard ammonia device and the other for the cascade NH3/CO2 device. Both cycles are processes with two-stage compression and two-stage throttling. The thermodynamic analysis demonstrates that the selected refrigeration cycle is the most cost-effective process because it provides the best numerical values for the total refrigeration factor with respect to the observed refrigeration cycle. The chief analyzed influential parameters of the cascade device are: total refrigeration load, total reactive power, mean temperature of the heat exchanger, evaporating and condensing temperature of the low-temperature part.

Ecological optimization for generalized irreversible Carnot refrigerators

International Nuclear Information System (INIS)

Chen Lingen; Zhu Xiaoqin; Sun Fengrui; Wu Chih

2005-01-01

The optimal ecological performance of a Newton's law generalized irreversible Carnot refrigerator with the losses of heat resistance, heat leakage and internal irreversibility is derived by taking an ecological optimization criterion as the objective, which consists of maximizing a function representing the best compromise between the exergy output rate and exergy loss rate (entropy production rate) of the refrigerator. Numerical examples are given to show the effects of heat leakage and internal irreversibility on the optimal performance of generalized irreversible refrigerators

Defrost Temperature Termination in Supermarket Refrigeration Systems

Energy Technology Data Exchange (ETDEWEB)

Fricke, Brian A [ORNL; Sharma, Vishaldeep [ORNL

2011-11-01

The objective of this project was to determine the potential energy savings associated with implementing demand defrost strategies to defrost supermarket refrigerated display case evaporators, as compared to the widely accepted current practice of controlling display case defrost cycles with a preset timer. The defrost heater energy use of several representative display case types was evaluated. In addition, demand defrost strategies for refrigerated display cases as well as those used in residential refrigerator/freezers were evaluated. Furthermore, it is anticipated that future work will include identifying a preferred defrost strategy, with input from Retail Energy Alliance members. Based on this strategy, a demand defrost system will be designed which is suitable for supermarket refrigerated display cases. Limited field testing of the preferred defrost strategy will be performed in a supermarket environment.

Applicability of microautoradiography to sorption studies

International Nuclear Information System (INIS)

Thompson, J.L.; Wolfsberg, K.

1979-01-01

The technique of microautoradiography was applied to the study of the sorption of uranium and americium on five rock types which exist at the Nevada Test Site. It was found that autoradiograms could be prepared in a few days which would allow the specific minerals responsible for sorption to be identified. Furthermore, the state of aggregation of the sorbed species was clearly indicated. It was concluded that microautoradiography was a useful adjunct to currently used methods for studying sorption of certain radionuclides

The role of refrigerants in climate change

International Nuclear Information System (INIS)

Wuebbles, D.J.

1992-06-01

The primary chemicals used as refrigerants, chlorofluorocarbons (CFCs), and the compounds being considered as their replacements (HCFCs and HFCs) have been intensely studied because of concerns about chlorine chemistry effects on stratospheric ozone. Increasing attention is being given to the potential effects of these compounds in concerns about global warming. CFCs, HCFCs, and HFCs absorb infrared radiation and thus are greenhouse gases that can influence radiative forcing on climate. The purpose of this paper is to describe the current understanding of the role of refrigerants in affecting climate. Increasing atmospheric concentrations of CFCs have accounted for about 24 % of the direct increase in radiative forcing from greenhouse gases over the last decade. However, observed decreases in stratospheric ozone, thought to be connected to increasing stratospheric chlorine from CFCs, suggests a cooling tendency over the last decade. This cooling tendency has strong latitudinal gradients, but is, when globally averaged, about comparable in magnitude and opposite in sign to the radiative forcing from CFCs over this period. Because of their shorter atmospheric lifetimes, the direct radiative influence on climate from the replacement compounds should generally be much smaller than the CFCs

Public Refrigerated Warehouses

Data.gov (United States)

Department of Homeland Security — The International Association of Refrigerated Warehouses (IARW) came into existence in 1891 when a number of conventional warehousemen took on the demands of storing...

Development of Web-based Software for Sorption Database

International Nuclear Information System (INIS)

Han, Byoung Sub; Lee, Jae Min; Seo, Min Seok; Kim, Dong Keon

2009-08-01

Sorption studies of radionuclides are important parts of research on radioactive waste disposal which is commonly faced in most countries where nuclear programs (power production, a variety of peaceful applications, and research) are implemented. The Sorption Database (DB) plays a very important role in the safety assessment of the radioactive waste disposal. The Sorption DB which is opened externally can be used as reference material of establishing a national policy by improving and changing the pre-developed Sorption program to be web-based. From the industrial point of view, if the Sorption DB is opened to the outside, the safety-related confidence can be achieved for nuclear industry. As the information of Sorption DB is opened, not only credibility can be provided to the administration, local governments and nearby residents, but also input of the collected information can be achieved by online. In addition, the reference material and external awareness/reliability about the domestic level of the Sorption DB management system and the current state can be achieved internationally. In order to provide the information of Sorption DB to users in more efficient way, the analysis and complement of management and search capability for the existing Sorption DB program have been performed and web-based management system has been built to provide services to users. In addition, by applying statistical techniques, it has been designed and implemented to display the accuracy and error of the information

Cobalt sorption onto Savannah River Plant soils

International Nuclear Information System (INIS)

Hoeffner, S.L.

1985-06-01

A laboratory study of cobalt-60 sorption was conducted using Savannah River Plant soil and groundwater from the low-level waste burial ground. Systematic variation of soil and water composition indicates that cobalt sorption is most strongly a function of pH. Over a pH range of 2 to 9, the distribution coefficient ranged from 2 to more than 10,000 mL/g. Changes in clay content and in K + , Ca 2+ , or Mg 2+ concentrations influence cobalt sorption indirectly through the slight pH changes which result. The ions Na + , Cl - , and NO 3 - have no effect on cobalt sorption. Ferrous ion, added to groundwater to simulate the condition of water at the bottom of the waste trenches, accounts for part of the decrease in cobalt sorption observed with trench waters. 17 refs., 3 figs., 4 tabs

Artificial Weathering of Biotite and Uranium Sorption Characteristics

International Nuclear Information System (INIS)

Lee, Seung Yeop; Baik, Min Hoon; Lee, Jae Kwang

2009-01-01

An experiment for uranium sorption onto fresh and weathered biotites was performed. After centrifugation, concentrations of uranium in the supernatants were analyzed using ICP-MS, and biotite samples were investigated using XRD and SEM. With powdered biotites (<3 mm in size), we have conducted uranium sorption experiments about fresh and weathered biotites to obtain uranium sorption amounts in various pH conditions. The uranium sorption was not high at a low pH (e.g., pH 3), but increased with increasing pH. There were lower uranium sorption by the weathered biotites than by the fresh ones, and the difference was much larger at higher pH (e.g., pH 11). The lower sorption values of uranium by the weathered biotites may be caused by a change of mineral surfaces and a chemical behavior of surrounding dissolved elements. It seems that the uranium-mineral interaction has been diminished, especially, in the weathered biotite by a destruction and dissolution of preferential sorption sites on the mineral surfaces and by the colloidal formation from dissolved elements.

Evaporation of new refrigerants on tubes with improved surfaces; Evaporation de nouveaux refrigerants sur des tubes a surface amelioree

Energy Technology Data Exchange (ETDEWEB)

Kattan, N.; Favrat, D.; Thome, J. R.; Nidegger, E.; Zuercher, O. [Ecole Polytechnique Federale, Lab. d` Energetique Industrielle (LENI), Lausanne (Switzerland)

1995-07-15

The substitution of old refrigerants in refrigeration systems, heat pumps and organic Rankine cycles for heat recovery, request a good knowledge of heat transfer properties of substitute fluids. The test measurements in LENI test facility (concentric tubes with water flowing in a counter-current flow) with new refrigerants like HFC134a, HCFC123, R-404A, R-402A, have established a new data bank with new refrigerants, a comparison with old refrigerants like CFC11, CFC12 CFC/HCFC502 and with existent correlations. Correlations were programmed to calculate and compare heat transfer coefficient during the tests. To develop a new correlation based on flow regimes, a high speed Sony video tape camera is used to observe and identify flow patterns. Important images are captured, digitalized, stored for later analysis and sent to a color plotter. Several flow pattern maps were programmed and compared to flow regimes observed on the test rig. Local flow boiling heat transfer coefficients were measured for HFC134a and HCFC123 evaporating inside a microfin tube. In addition, microfin heat transfer augmentation relative to plain tube test data was investigated. The presence of oil in the evaporator has an effect on heat transfer coefficient. Local flow boiling heat transfer coefficients were measured for refrigerant HFC134a-oil ester (Mobil EAL Arctic 68). A new thermodynamic approach for modeling mixtures of refrigerants and lubricating oils is developed. A very high accuracy, straight vibrating tube type of density flowmeter is used to measure oil concentrations of flowing HFC134a-oil mixtures. (author) 28 figs., 25 refs.

Geochemical modelling of the sorption of tetravalent radioelements

International Nuclear Information System (INIS)

Bond, K.A.; Tweed, C.J.

1991-05-01

The results of an experimental study of the sorption of a range of tetravalent radioelements, plutonium (IV), tin (IV), thorium(IV) and uranium(IV), onto clay at pH8 and pH11 have been successfully simulated using a triple layer sorption model. The model has been incorporated into HARPHRQ, a geochemical program based on PHREEQE. The model has been parameterised using data for sorption onto ferric oxyhydroxide and goethite. The effects of hydroxycarboxylic acids on the sorption process have also been investigated experimentally. It was generally observed that in the presence of 2x10 -3 M gluconate, sorption was reduced by up two orders of magnitude. The model has satisfactorily simulated these lower sorptivities, through assuming competing sorption and complexation reactions. This work, therefore, further confirms the need to take account of such organic materials in safety assessment modelling. (author)

Time-Temperature Profiling of United Kingdom Consumers' Domestic Refrigerators.

Science.gov (United States)

Evans, Ellen W; Redmond, Elizabeth C

2016-12-01

Increased consumer demand for convenience and ready-to-eat food, along with changes to consumer food purchase and storage practices, have resulted in an increased reliance on refrigeration to maximize food safety. Previous research suggests that many domestic refrigerators operate at temperatures exceeding recommendations; however, the results of several studies were determined by means of one temperature data point, which, given temperature fluctuation, may not be a true indicator of actual continual operating temperatures. Data detailing actual operating temperatures and the effects of consumer practices on temperatures are limited. This study has collated the time-temperature profiles of domestic refrigerators in consumer kitchens (n = 43) over 6.5 days with concurrent self-reported refrigerator usage. Overall, the findings established a significant difference (P < 0.05) between one-off temperature (the recording of one temperature data point) and mean operating temperature. No refrigerator operated at ≤5.0°C for the entire duration of the study. Mean temperatures exceeding 5.0°C were recorded in the majority (91%) of refrigerators. No significant associations or differences were determined for temperature profiles and demographics, including household size, or refrigerator characteristics (age, type, loading, and location). A positive correlation (P < 0.05) between room temperature and refrigerator temperature was determined. Reported door opening frequency correlated with temperature fluctuation (P < 0.05). Thermometer usage was determined to be infrequent. Cumulatively, research findings have established that the majority of domestic refrigerators in consumer homes operate at potentially unsafe temperatures and that this is influenced by consumer usage. The findings from this study may be utilized to inform the development of shelf-life testing based on realistic domestic storage conditions. Furthermore, the data can inform the development of future

Efficiency analysis of alternative refrigerants for ejector cooling cycles

International Nuclear Information System (INIS)

Gil, Bartosz; Kasperski, Jacek

2015-01-01

Highlights: • Advantages of using alternative refrigerants as ejector refrigerants were presumed. • Computer software basing on theoretical model of Huang et al. (1999) was prepared. • Optimal temperature range of primary vapor for each working fluid was calculated. - Abstract: Computer software, basing on the theoretical model of Huang et al. with thermodynamic properties of selected refrigerants, was prepared. Investigation was focused on alternative refrigerants that belong to two groups of substances: common solvents (acetone, benzene, cyclopentane, cyclohexane and toluene) and non-flammable synthetic refrigerants applied in Organic Rankine Cycle (ORC) (R236ea, R236fa, R245ca, R245fa, R365mfc and RC318). Refrigerants were selected to detect a possibility to use them in ejector cooling system powered by a high-temperature heat source. A series of calculations were carried out for the generator temperature between 70 and 200 °C, with assumed temperatures of evaporation 10 °C and condensation 40 °C. Investigation revealed that there is no single refrigerant that ensures efficient operation of the system in the investigated temperature range of primary vapor. Each substance has its own maximum entrainment ratio and COP at its individual temperature of the optimum. The use of non-flammable synthetic refrigerants allows obtaining higher COP in the low primary vapor temperature range. R236fa was the most beneficial among the non-flammable synthetic refrigerants tested. The use of organic solvents can be justified only for high values of motive steam temperature. Among the solvents, the highest values of entrainment ratio and COP throughout the range of motive temperature were noted for cyclopentane. Toluene was found to be an unattractive refrigerant from the ejector cooling point of view

Radionuclide sorption on crushed and intact granitic rock

International Nuclear Information System (INIS)

Eriksen, Tryggve E.; Locklund, Birgitta

1989-05-01

The specific surface areas and distribution ratios for sorption of 85 Sr, 137 Cs and 152 Eu were measured for crushed and intact granite rock. The experimental data can be accommodated by a sorption model encompassing sorption on outer and inner surface. It is clearly demonstrated that the time required to obtain reliable Kd-values for the sorption of strongly sorbing radionuclides like 152 Eu is very long due to solution depletion and slow diffusion into the rock. A combination of surface area measurements and batch sorption with small particles may therefore be preferable when studying strongly sorbing nuclides. (authors) (17 figs., 6 tabs.)

Magnetic refrigerator for hydrogen liquefaction

Energy Technology Data Exchange (ETDEWEB)

Numazawa, T [National Institute for Materials Science, Tsukuba (Japan); Kamlya, K. [Japan Atomic Energy Agency, Naka (Japan); Utaki, T. [Osaka University, Osaka (Japan); Matsumoto, K. [Kanazawa University, Kanazawa (Japan)

2013-06-15

This paper reviews the development status of magnetic refrigeration system for hydrogen liquefaction. There is no doubt that hydrogen is one of most important energy sources in the near future. In particular, liquid hydrogen can be utilized for infrastructure construction consisting of storage and transportation. Liquid hydrogen is in cryogenic temperatures and therefore high efficient liquefaction method must be studied. Magnetic refrigeration which uses the magneto-caloric effect has potential to realize not only the higher liquefaction efficiency > 50 %, but also to be environmentally friendly and cost effective. Our hydrogen magnetic refrigeration system consists of Carnot cycle for liquefaction stage and AMR (active magnetic regenerator) cycle for precooling stages. For the Carnot cycle, we develop the high efficient system > 80 % liquefaction efficiency by using the heat pipe. For the AMR cycle, we studied two kinds of displacer systems, which transferred the working fluid. We confirmed the AMR effect with the cooling temperature span of 12 K for 1.8 T of the magnetic field and 6 second of the cycle. By using the simulation, we estimate the total efficiency of the hydrogen liquefaction plant for 10 kg/day. A FOM of 0.47 is obtained in the magnetic refrigeration system operation temperature between 20 K and 77 K including LN2 work input.

Sorption of uranyl ions on hydrous oxides

International Nuclear Information System (INIS)

Gupta, A.R.; Venkataramani, B.

1988-01-01

Sorption of uranyl ions on hydrous titanium oxide (HTiO), magnetite (MAG), and hydrous thorium oxide (HThO) has been studied as a function of pH. Hydrous oxides have been characterized by their pH-titration curves, intrinsic dissociation constants (pK ai * ) and point of zero charge (pH pzc ). The fraction of protonated surface hydroxyl groups as well as the surface pH (pH surf ) as a function of solution pH have been computed. The distribution of various hydrolyzed species of uranyl ions with solution pH have been compared with uranyl sorption isotherm on these oxides. Sorption edge in all the cases occurs when free hydroxyl groups are available on the surface and pH surf is sufficiently high to favor the formation of dimer-like species on the surface. A new model for the sorption process, called surface hydrolysis model, which explains these and other features of uranyl sorption on hydrous oxides has been proposed. The model visualizes the sorption process as linking of uranyl ions with two adjacent free surface hydroxyl groups without deprotonation (provided the surface pH is high for the hydrolysis of uranyl ions) and formation of dimer-like structures on the surface. The new model has been successfully applied to the present and other available data on uranyl ion sorption on hydrous oxides. (author)

Reducing heat transfer across the insulated walls of refrigerated truck trailers by the application of phase change materials

International Nuclear Information System (INIS)

Ahmed, Mashud; Meade, Oliver; Medina, Mario A.

2010-01-01

A general estimate shows that 80% of communities across the United States receive their goods exclusively by transport trucks, of which a significant number are climate-controlled because they carry perishable goods, pharmaceutical items and many other temperature-sensitive commodities. Keeping the inside of a truck trailer at a constant temperature and relative humidity requires exact amounts of heat and/or moisture management throughout the shipment period, which is regulated via small refrigeration units, placed outside the truck, that operate by burning fuel. These trucks, known as refrigerated truck trailers, are the focus of this paper. In the research presented herein, the conventional method of insulation of the refrigerated truck trailer was modified using phase change materials (PCMs). The limited research carried out in refrigerated transport compared to other refrigeration processes has left spaces for innovative solutions in this area. The research investigated the inclusion of paraffin-based PCMs in the standard trailer walls as a heat transfer reduction technology. An average reduction in peak heat transfer rate of 29.1% was observed when all walls (south, east, north, west, and top) were considered. For individual walls, the peak heat transfer rate was reduced in the range of 11.3-43.8%. Overall average daily heat flow reductions into the refrigerated compartment of 16.3% were observed. These results could potentially translate into energy savings, pollution abatement from diesel-burning refrigeration units, refrigeration equipment size reduction, and extended equipment operational life. The research and its results will help to better understand the scope of this technology.

Effect of the cationic composition of sorption solution on the quantification of sorption-desorption parameters of heavy metals in soils

International Nuclear Information System (INIS)

Sastre, J.; Rauret, G.; Vidal, M.

2006-01-01

We obtained the sorption isotherms of Cd, Cu, Pb and Zn in clay, clay saline and organic soils. The distribution coefficients (K d ) were determined in 0.02 eq l -1 CaCl 2 and in a solution that simulated the soil solution cationic composition. The K d values greatly varied with the composition of the sorption solution and the initial metal concentration. The sorption experiments were complemented with the quantification of the extractable metal, to estimate the reversibility of metal sorption. The extraction yields depended on the metal-soil combination, and the initial metal concentration, showing no correlation with previous K d values. The effect of the solution composition in mobility predictions was estimated through a Retention Factor, defined as the ratio of the K d versus the extraction yield. Results showed that risk was over- or underestimated using the CaCl 2 medium in soils with a markedly different soil solution composition. - Sorption solution composition modifies metal sorption-desorption pattern in soils

Studies on the quality of duck meat sausages during refrigeration.

Science.gov (United States)

Naveen, Z; Naik, B R; Subramanyam, B V; Reddy, P M

2016-01-01

Duck farming is on the raise in the current scenario, but processed products from duck meat are still uncommon to find. Investigating the duck meat qualities during storage will provide information to enhance duck meat utilization. Development of ready-to-eat and ready-to-cook duck meat products is expected to increase and improve non-chicken meat-based protein. The Study was aimed to evaluate the changes in quality characteristics of duck meat sausages preserved by refrigeration (7 ± 1 °C). Duck meat sausages were prepared by utilizing raw and partially cooked duck meat with addition of soy flour at 10% level as a binder. Different quality characteristics like physical and chemical characteristics, proximate composition, and organoleptic characteristics were evaluated. Cooking loss of partially cooked meat sausages was lower than raw duck meat sausages, whereas emulsion stability and 2-thiobarbituric acid (TBA) values of raw duck meat sausages were lesser than partially cooked meat sausages. Cooking loss and emulsion stability decreased in both types of meat sausages, while, 2-TBA values increased as refrigerated storage progressed for 14 days. Percent moisture content of raw duck meat sausages was higher than partially cooked meat sausages, which decreased in both types of meat sausages as refrigerated storage progressed for 14 days. Percent crude protein (CP) and percent ether extract (EE) content of partially cooked duck meat sausages were higher than raw duck meat sausages. Regardless of type of meat used, refrigerated storage of sausages increased CP and EE up to 10th day but decreased upon further storage up to 14th day. Organoleptic scores for raw duck meat sausages were higher than partially cooked duck meat sausages and all the scores decreased with an increase in the storage period. However the scores were within the acceptable limits. The findings prove that, duck meat can be effectively acclaimed as an alternative avenue to meet the escalating

Classification of refrigerants; Classification des fluides frigorigenes

Energy Technology Data Exchange (ETDEWEB)

NONE

2001-07-01

This document was made from the US standard ANSI/ASHRAE 34 published in 2001 and entitled 'designation and safety classification of refrigerants'. This classification allows to clearly organize in an international way the overall refrigerants used in the world thanks to a codification of the refrigerants in correspondence with their chemical composition. This note explains this codification: prefix, suffixes (hydrocarbons and derived fluids, azeotropic and non-azeotropic mixtures, various organic compounds, non-organic compounds), safety classification (toxicity, flammability, case of mixtures). (J.S.)

Ab-sorption machines for heating and cooling in future energy systems - Final report

Energy Technology Data Exchange (ETDEWEB)

Tozer, R.; Gustafsson, M.

2000-12-15

After the Executive Summary and a brief introductory chapter, Chapter 2, Sorption Technologies for Heating and Cooling in Future Energy Systems, reviews the main types of sorption systems. Chapter 3, Market Segmentation, then considers the major segments of the market including residential, commercial/institutional and industrial, and the types of sorption hardware most suitable to each. The highly important residential and commercial/institutional markets are mostly concerned with air-conditioning of buildings. More applications are identified and discussed for the industrial market, including refrigeration, food-storage cooling, process cooling, and process heating at various temperature ranges from hot water for hand-washing to high-temperature (greater than 130C). Other interesting industrial applications are absorption cooling or heating combined with co-generation, desiccant cooling, gas turbine inlet air cooling, combining absorption chillers with district heating systems, direct-fired absorption heat pumps (AHPs), and a closed greenhouse concept being developed for that economically important sector in the Netherlands. Most of the sorption market at this time comprises direct-fired absorption chillers, or hot water or steam absorption chillers indirectly driven by direct-fired boilers. Throughout the report, this category of absorption chillers is referred to generically as 'direct-fired'. In addition, this report covers absorption (reversible) heat pumps, absorption heat transformers, compression-absorption heat pumps, and adsorption chillers and heat pumps. Adsorption systems together with desiccant systems are also addressed. Chapter 4, Factors Affecting the Market, considers economic, environmental and policy issues. The geographical make-up of the world sorption market is then reviewed, followed by a number of practical operating and control considerations. These include vacuum requirements, crystallisation, corrosion, maintenance, health and

Sorption of humic acid to functionalized multi-walled carbon nanotubes

International Nuclear Information System (INIS)

Wang, Fei; Yao, Jun; Chen, Huilun; Yi, Zhengji; Xing, Baoshan

2013-01-01

The environmental behavior of carbon nanotubes (CNTs) and humic acid (HA) is a prominent concern, but effect of functionalities on their sorption is not clear yet. Functionalized multi-walled CNTs (MCNT15) and HA were used to study their sorption behavior. Sorption rate of HA to MCNTs was dominantly controlled by its diffusion from liquid-MCNT boundary to MCNT surfaces. The sorption is in the sequence of MCNT15 > MCNT15-NH 2 > MCNT15-OH > MCNT15-COOH > MCNT15-Ni, which was dependent on their surface area and meso- and macro-pore volume. The functionalities of MCNTs regulated the sorption by affecting their interaction mechanisms (i.e., H-bonding, π–π, and hydrophobic interaction). Additionally, the amount of these functionalities on the MCNT surface reduced indirectly the sorption sites due to the steric hindrance. Electrostatic repulsion deceased the sorption of HA by MCNTs with increasing pH. This study demonstrated the importance of functionalities on the MCNTs for the sorption of HA. -- Highlights: •HA sorption kinetics was well fitted using Lagergren pseudo second-order model. •Sorption rate of HA was controlled by diffusion from liquid-MCNT boundary to MCNT surfaces. •Sorption was dependent on their surface area and meso- and macro-pore volume. •Functionalities of MCNTs regulated the sorption by affecting interaction mechanisms. -- The functionalities of MCNTs regulated the sorption behavior between MCNTs and HA

Sorption on inactive repository components

International Nuclear Information System (INIS)

Gardiner, M.P.; Smith, A.J.; Williams, S.J.

1990-11-01

The near-field of an intermediate level/low level radioactive waste repository will contain significant quantities of iron and steel, Magnox and Zircaloy. Their corrosion products may possess significant sorption capacity for radioelements. The sorption of americium and plutonium onto magnesium hydroxide, zirconium hydroxide, colloidal magnetite and colloidal haematite has been studied under conditions typical of the porewater of a cementitious near-field. R D values ≥ 10 5 m g -1 were measured for both actinides on the oxides and hydroxides. These values are at least as great as those measured on crushed 3:1 Blast Furnace Slag/Ordinary Portland cement. Competitive sorption experiments have shown that sorption onto the corrosion products does not take place in preference to that on the cement or the converse. Magnetite and haematite colloids are positively charged in cement-equilibrated water whilst zirconium hydroxide is negatively charged. Crushed cement was found to be positively charged. Simple experiments show that only a small proportion of haematite colloids is potentially mobile through a column of crushed cement. (author)

Sorption on inactive repository components

International Nuclear Information System (INIS)

Gardiner, M.P.; Smith, A.J.; Williams, S.J.

1990-07-01

The near-field of an intermediate level/low level radioactive waste repository will contain significant quantities of iron and steel, Magnox and Zircaloy. Their corrosion products may possess significant sorption capacity for radioelements. The sorption of americium and plutonium onto magnesium hydroxide, zirconium hydroxide, colloidal magnetite and colloidal haematite has been studied under conditions typical of the porewater of a cementitious near-field. R D values ≥ 10 5 ml g -1 were measured for both actinides on the oxides and hydroxides. These values are at least as great at those measured on crushed 3:1 Blast Furnace Slag/Ordinary Portland Cement. Competitive sorption experiments have shown that sorption onto the corrosion products does not take place in preference to that on the cement or the converse. Magnetite and haematite colloids are positively charged in cement-equilibrated water whilst zirconium hydroxide is negatively charged. Crushed cement was found to be positively charged. Simple experiments show that only a small proportion of haematite colloids is potentially mobile through a column of crushed cement. (author)

Sorption of organophosphate esters by carbon nanotubes

Energy Technology Data Exchange (ETDEWEB)

Yan, Wei; Yan, Li [State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085 (China); Duan, Jinming [School of Environmental and Municipal Engineering, Xi’an University of Architecture and Technology, Xi’an 710055 (China); Jing, Chuanyong, E-mail: cyjing@rcees.ac.cn [State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085 (China)

2014-05-01

Graphical abstract: The interfacial interactions between the OPE molecules and CNTs. - Highlights: • Oxygen-containing groups on CNTs change the sorption property for OPEs. • Molecular configuration of OPEs has insignificant impact on their sorption. • Hydrophobic, π–π EDA and Brønsted acid–base interaction occurred between the CNTs and OPEs. - Abstract: Insights from the molecular-level mechanism of sorption of organophosphate esters (OPEs) on carbon nanotubes (CNTs) can further our understanding of the fate and transport of OPEs in the environment. The motivation for our study was to explore the sorption process of OPEs on multi-walled CNTs (MWCNTs), single-walled CNTs (SWCNTs) and their oxidized counterparts (O-MWCNTs and O-SWCNTs), and its molecular mechanism over a wide concentration range. The sorption isotherm results revealed that the hydrophobicity of OPEs dominated their affinities on a given CNT and the π–π electron donor–acceptor (EDA) interaction also played an important role in the sorption of aromatic OPEs. This π–π EDA interaction, verified with Raman and FT-IR spectroscopy, could restrict the radial vibration of SWCNTs and affect the deformation vibration γ(CH) bands of OPE molecules. The OPE surface coverage on CNTs, estimated using the nonlinear Dubinin–Ashtakhov model, indicated that the oxygen-containing functional groups on CNTs could interact with water molecules by H-bonding, resulting in a decrease in effective sorption sites. In addition, FTIR analysis also confirmed the occurrence of Brønsted acid–base interactions between OPEs and surface OH groups of SWCNTs. Our results should provide mechanistic insights into the sorption mechanism of OPE contaminants on CNTs.

Sorption of cesium and uranium to Feldspar

International Nuclear Information System (INIS)

Wijland, G.C.; Pennders, R.M.J.

1990-07-01

Within safety assessment studies, for nuclear waste disposal in deep geologic formations, calculation for the migration of radionuclides through the geosphere are often carried out with models taking sorption into account. In the past 8 years the insight grew that other physico-chemical processes, besides sorption, could affect migration behaviour. While the currently used transport models were being improved taking either linear or non-linear sorption into account, the coupling of geochemical and transport models came into scope. In spite of these developments models which are still based on the sorption theory are frequently applied in studying migration behaviour of radionuclides. This is caused by the necessity of making preliminary pronouncements, while coupled models are still in stage of development and thermodynamic data are very limited available. Therefore one has to obtain insight in the reliability of the models based on the sorption theory. within the sorption database there is a lack of knowledge about mineralogy, composition of the fluid and the experimental conditions underlying the data. Therefore the Expert Group on geochemical Modelling supported by the Finnish proposal in order to obtain insight in the possible deviation of the sorption coefficients that can be estimated from experiments performed with standard samples, fluid composition and experimental conditions. Nine laboratories from OECD membership countries took part in this intercalibration study. In the framework of the Dutch safety assessment studies the Dutch National Institute of Public health and Environmental protection (RIVM) has decided to participate in this exercise. In this report the results are presented of sorption experiments for cesium and natural Uranium to Feldspar. (H.W.). 4 refs.; 1 fig.; 7 tabs

CFD simulation and experimental validation of a GM type double inlet pulse tube refrigerator

Science.gov (United States)

Banjare, Y. P.; Sahoo, R. K.; Sarangi, S. K.

2010-04-01

Pulse tube refrigerator has the advantages of long life and low vibration over the conventional cryocoolers, such as GM and stirling coolers because of the absence of moving parts in low temperature. This paper performs a three-dimensional computational fluid dynamic (CFD) simulation of a GM type double inlet pulse tube refrigerator (DIPTR) vertically aligned, operating under a variety of thermal boundary conditions. A commercial computational fluid dynamics (CFD) software package, Fluent 6.1 is used to model the oscillating flow inside a pulse tube refrigerator. The simulation represents fully coupled systems operating in steady-periodic mode. The externally imposed boundary conditions are sinusoidal pressure inlet by user defined function at one end of the tube and constant temperature or heat flux boundaries at the external walls of the cold-end heat exchangers. The experimental method to evaluate the optimum parameters of DIPTR is difficult. On the other hand, developing a computer code for CFD analysis is equally complex. The objectives of the present investigations are to ascertain the suitability of CFD based commercial package, Fluent for study of energy and fluid flow in DIPTR and to validate the CFD simulation results with available experimental data. The general results, such as the cool down behaviours of the system, phase relation between mass flow rate and pressure at cold end, the temperature profile along the wall of the cooler and refrigeration load are presented for different boundary conditions of the system. The results confirm that CFD based Fluent simulations are capable of elucidating complex periodic processes in DIPTR. The results also show that there is an excellent agreement between CFD simulation results and experimental results.

Optimizing the Thermoacoustic Pulse Tube Refrigerator Performances

Directory of Open Access Journals (Sweden)

E. V. Blagin

2014-01-01

Full Text Available The article deals with research and optimization of the thermoacoustic pulse tube refrigerator to reach a cryogenic temperature level. The refrigerator is considered as a thermoacoustic converter based on the modified Stirling cycle with helium working fluid. A sound pressure generator runs as a compressor. Plant model comprises an inner heat exchanger, a regenerative heat exchanger, a pulse tube, hot and cold heat exchangers at its ends, an inertial tube with the throttle, and a reservoir. A model to calculate the pulse tube thermoacoustic refrigerator using the DeltaEC software package has been developed to be a basis for calculation techniques of the pulse tube refrigerator. Momentum, continuity, and energy equations for helium refrigerant are solved according to calculation algorithm taking into account the porosity of regenerator and heat exchangers. Optimization of the main geometric parameters resulted in decreasing temperature of cold heat exchanger by 41,7 K. After optimization this value became equal to 115,01 K. The following parameters have been optimized: diameters of the feeding and pulse tube and heat exchangers, regenerator, lengths of the regenerator and pulse and inertial tubes, as well as initial pressure. Besides, global minimum of temperatures has been searched at a point of local minima corresponding to the optimal values of abovementioned parameters. A global-local minima difference is 0,1%. Optimized geometric and working parameters of the thermoacoustic pulse tube refrigerator are presented.

Computer modeling of commercial refrigerated warehouse facilities

International Nuclear Information System (INIS)

Nicoulin, C.V.; Jacobs, P.C.; Tory, S.

1997-01-01

The use of computer models to simulate the energy performance of large commercial refrigeration systems typically found in food processing facilities is an area of engineering practice that has seen little development to date. Current techniques employed in predicting energy consumption by such systems have focused on temperature bin methods of analysis. Existing simulation tools such as DOE2 are designed to model commercial buildings and grocery store refrigeration systems. The HVAC and Refrigeration system performance models in these simulations tools model equipment common to commercial buildings and groceries, and respond to energy-efficiency measures likely to be applied to these building types. The applicability of traditional building energy simulation tools to model refrigerated warehouse performance and analyze energy-saving options is limited. The paper will present the results of modeling work undertaken to evaluate energy savings resulting from incentives offered by a California utility to its Refrigerated Warehouse Program participants. The TRNSYS general-purpose transient simulation model was used to predict facility performance and estimate program savings. Custom TRNSYS components were developed to address modeling issues specific to refrigerated warehouse systems, including warehouse loading door infiltration calculations, an evaporator model, single-state and multi-stage compressor models, evaporative condenser models, and defrost energy requirements. The main focus of the paper will be on the modeling approach. The results from the computer simulations, along with overall program impact evaluation results, will also be presented

New possibilities for non-CFC refrigeration

International Nuclear Information System (INIS)

Lorentzen, G.; Pettersen, J.

1992-01-01

There is a widespread belief that the only viable refrigerants in most applications are new fluorocarbon chemicals. This trend will eventually result in emissions of several hundred thousand tons of new chemicals to the atmosphere each year, involving potential risk of unforeseen environmental effects. A number of other options exist, or may be developed. By using substances which already have a natural role in our ecosystems, some uncertainty related to the critical issue of our future environment can be avoided. By development and practical testing of a laboratory prototype it has been documented that carbon dioxide is a viable refrigerant in automobile air conditioners, completely solving all environmental problems associated with such systems. General use of CO 2 as a refrigerant may provide a number of advantages in the present situation, both from an environmental and practical point of view. It is our considered opinion that the old carbon dioxide offers a key to the complete solution of the environmental problems in many areas of refrigeration usage. 19 refs., 8 figs., 5 tabs

Impact of Refrigerated Storage on Quality of Oil from Freshwater Jarko (Wallago attu Fish.

Directory of Open Access Journals (Sweden)

Nusrat N. Memon

2010-12-01

Full Text Available The effect of refrigerated storage on the quality of freshwater fish oil Jarko (Wallago attu was evaluated by measuring fatty acid profile, free fatty acids (FFA, peroxide value (PV, acid value (AV, sponification value (SV, iodine value (IV and poylene index (PI up to the time period of 120 days. After 120 days storage, mono unsaturated fatty acids (MUFA and polyunsaturated fatty acids (PUFA contents were decreased by 24.89% and 33.70%, respectively. While, saturated fatty acids (SFA content was found to be increased by 26.82%, against the actual value. The change in polyunsaturated fatty acids during refrigerated storage was measured by the PI value. The PI decreased during storage due to lipid oxidation, but remained nearly constant after 90th day of storage. The results of PV, AV and FFA demonstrates that Wallago attu fish oil remained acceptable for consumption for 60 days but eventually exceeded the recommended values after 60 days of refrigerated storage.

Pu sorption to activated conglomerate anaerobic bacteria

International Nuclear Information System (INIS)

Sasaki, Takayuki; Kudo, Akira

2001-01-01

The sorption of Pu to the anaerobic bacteria activated under specific conditions of temperature, pH and depleted nutrients after long dormant period was investigated. After 4 h at neutral pH, the distribution coefficient (K d ) between bacteria and aqueous phase at 308 and 278 K had around 10 3 to 10 4 . After over 5 days, however, the K d at only 308 K had increased to over 10 5 . Sterilized (dead) and dormant anaerobic bacteria adsorbed Pu to the same extent. (author)

Strontium sorption on Savannah River Plant soils

International Nuclear Information System (INIS)

Hoeffner, S.L.

1984-12-01

A laboratory study of strontium-85 sorption was conducted using Savannah River Plant soil and groundwater from the low-level waste burial ground. Systematic variation of soil and water composition indicates that strontium sorption is most strongly a function of pH. Changes in clay content and in K + , Ca 2+ , or Mg 2+ concentrations influence strontium sorption indirectly through the slight pH changes which result. The ions Na + , Cl - , and NO 3 - have no effect. Ferrous ion, added to groundwater to simulate the conditions of water at the bottom of waste trenches, did not account for low strontium sorption observed with some trench waters

Study of the radium sorption/desorption on goethite

International Nuclear Information System (INIS)

Bassot, S.; Stammose, D.; Mallet, C.; Lefebvre, C.; Ferreux, J.-M.

2000-01-01

The oxi-hydroxides, present at trace level in uranium mill tailings, are responsible of about 70% of the 226 radium sorption, half being fixed on crystallized forms. This radionuclide (half time=1622y), present at high level (50 to 100kBq.kg -1 ), can be released in groundwater, involving a possible contamination of the food chain (actual concentration limit=0.37Bq.1 -1 ). So, it is very important to point out the mechanisms of the radium sorption/desorption on crystallized oxi-hydroxides as a function of chemical conditions of the system. The radium sorption on synthetic goethite α-FeOOH has been studied as a function of contact time, initial radium activity, pH, sodium and calcium concentrations. The results show that, after one hour of contact time (necessary to reach equilibrium), the radium sorption increases widely in a pH range 6-7. The increase of Na + concentration is without influence on the radium sorption, indicating the low interactions between sodium and surface sites. At the opposite, the presence of calcium in solution decreases widely the radium sorption, that indicates a competition between calcium and radium for the same kind of sorption sites of the oxi-hydroxide surface. The percentage of radium desorbed increases widely with time, from 1 to 120h and becomes constant at a time higher than 120h. This long equilibrium time for desorption in comparison with sorption one can be explain by a local evolution of the sorption sites of the solid, which become less accessible for the solution in contact. (author)

ESO2 Optimization of Supermarket Refrigeration Systems

DEFF Research Database (Denmark)

Petersen, Lars Norbert; Madsen, Henrik; Heerup, Christian

Supermarket refrigeration systems consists of a number of display cases, cooling cabinets and cold rooms connected to a central compressor pack. This configuration saves energy compared to placing a compressor at each cooling site. The classical control setup of a supermarket refrigeration system...... in the supermarket. The first approach to solve this problem is to design an overall control system which coordinates the compressor capacity and the current refrigeration load. The drawback of this approach is the complexity of the single controller. The solution is investigated in the first part of the report...

Influence of selected factors on strontium sorption on bentonites

International Nuclear Information System (INIS)

Galambos, M.; Kufcakova, J.; Rajec, P.

2007-01-01

Sorption on bentonite will play an important role in retarding the migration of radionuclides from a waste repository. Bentonite is a natural clay and one of the most promising candidates for use as a buffer material in the geological disposal systems for high-level nuclear waste. It is intended to isolate metal canisters with highly radioactive waste products from the surrounding rocks because of its ability to retard the movement of radionuclides by sorption. Bentonite is characterized by low permeability, water swelling capability and excellent sorption potential for cationic radionuclides. To correctly assess the sorption potential of radionuclides on bentonite is essential for the development of predictive migration models. The sorption of strontium on bentonite from different Slovak deposits - Jelsovy potok, Kopernica and Lieskovec has been investigated under various experimental conditions, such as contact time, sorbate concentrations, presence of complementary cation. Sorption was studied using the batch technique. The uptake of Sr was rapid and equilibrium was reached almost instantaneously. The instantaneous uptake may be due to adsorption and/or exchange of the metal with some ions on the surface of the adsorbent. The best sorption characteristics distinguish bentonite Kopernica, sorption capacity for Sr of the fraction under 45 mm is 0,48 mmol·g -1 for Sr. The highest values of distribution coefficient were reached for the bentonite Jelsovy potok. Radiation stability has been investigated, the higher sorption parameters were observed for the irradiated bentonites, which can be explained by the increase of specific surface of the bentonite samples. The presence of complementary cations depresses the sorption of Sr on bentonite. Cations Ca 2+ exhibit higher effect on cesium sorption than the Na 2+ ions. Results indicate that the sorption of Sr 2+ on bentonite will be affected by the presence of high concentrations of various salts in the waste water

Sorption of citalopram, irbesartan and fexofenadine in soils: Estimation of sorption coefficients from soil properties.

Science.gov (United States)

Klement, Aleš; Kodešová, Radka; Bauerová, Martina; Golovko, Oksana; Kočárek, Martin; Fér, Miroslav; Koba, Olga; Nikodem, Antonín; Grabic, Roman

2018-03-01

The sorption of 3 pharmaceuticals, which may exist in 4 different forms depending on the solution pH (irbesartan in cationic, neutral and anionic, fexofenadine in cationic, zwitter-ionic and anionic, and citalopram cationic and neutral), in seven different soils was studied. The measured sorption isotherms were described by Freundlich equations, and the sorption coefficients, K F (for the fixed n exponent for each compound), were related to the soil properties to derive relationships for estimating the sorption coefficients from the soil properties (i.e., pedotransfer rules). The largest sorption was obtained for citalopram (average K F value for n = 1 was 1838 cm 3  g -1 ) followed by fexofenadine (K F  = 35.1 cm 3/n μg 1-1/n g -1 , n = 1.19) and irbesartan (K F  = 3.96 cm 3/n μg 1-1/n g -1 , n = 1.10). The behavior of citalopram (CIT) in soils was different than the behaviors of irbesartan (IRB) and fexofenadine (FEX). Different trends were documented according to the correlation coefficients between the K F values for different compounds (R IRB,FEX  = 0.895, p-valuesoil properties in the pedotransfer functions. While the K F value for citalopram was positively related to base cation saturation (BCS) or sorption complex saturation (SCS) and negatively correlated to the organic carbon content (Cox), the K F values of irbesartan and fexofenadine were negatively related to BCS, SCS or the clay content and positively related to Cox. The best estimates were obtained by combining BCS and Cox for citalopram (R 2  = 93.4), SCS and Cox for irbesartan (R 2  = 96.3), and clay content and Cox for fexofenadine (R 2  = 82.9). Copyright © 2017 Elsevier Ltd. All rights reserved.

RESEARCH OF REFRIGERATION SYSTEMS FAILURES IN POLISH FISHING VESSELS

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Waldemar KOSTRZEWA

2013-07-01

Full Text Available Temperature is a basic climatic parameter deciding about the quality change of fishing products. Time, after which qualitative changes of caught fish don’t exceed established, acceptable range, is above all the temperature function. Temperature reduction by refrigeration system of the cargo hold is a basic technical method, which allows extend transport time. Failures of refrigeration systems in fishing vessels have a negative impact on the environment in relation to harmful refrigerants emission. The paper presents the statistical analysis of failures occurred in the refrigeration systems of Polish fishing vessels in 2007‐2011 years. Analysis results described in the paper can be a base to draw up guidelines, both for designers as well as operators of the marine refrigeration systems.

Sorption of methylxanthines by different sorbents

Science.gov (United States)

Dmitrienko, S. G.; Andreeva, E. Yu.; Tolmacheva, V. V.; Terent'eva, E. A.

2013-05-01

Sorption of caffeine, theophylline, theobromine, diprophylline, and pentoxyphylline on different sorbents (supercross-linked polystyrene, surface-modified copolymer of styrene and divinylbenzene Strata-X, and carbon nanomaterials Taunit and Diasorb-100-C16T) was studied in a static mode in an effort to find new sorbents suitable for sorption isolation and concentration of methylxanthines. The peculiarities of sorption of methylxanthines were explained in relation to the solution acidity, the nature of the sorbates and their concentration, the nature of the solvent, and the structural characteristics of the sorbents.

Sorption isolation of strontium from seawater

International Nuclear Information System (INIS)

Avramenko, V.A.; Zheleznov, V.V.; Kaplun, E.V.; Sokol'nitskaya, T.A.; Yukhkam, A.A.

2001-01-01

Sorption isolation of strontium from seawater is considered and prospects of use of selective adsorbents for purification of seawater or liquid radioactive wastes mixed with seawater from 90 Sr are discussed. Comparative analysis of sorptive properties of adsorbents of different nature is done. It is shown that sorption-reagent materials developed by authors can to afford effective separation of 90 Sr from seawater. Possible mechanism of strontium sorption by these adsorbents is considered. The prospect of their use for purification of liquid radioactive wastes from strontium is shown [ru

PIPER Continuous Adiabatic Demagnetization Refrigerator

Science.gov (United States)

Kimball, Mark O.; Shirron, Peter J.; Canavan, Edgar R.; James, Bryan L.; Sampson, Michael A.; Letmate, Richard V.

2017-01-01

We report upon the development and testing of a 4-stage adiabatic demagnetization refrigerator (ADR) capable of continuous cooling at 0.100 Kelvin. This cooler is being built to cool the detector array aboard NASA's Primordial Inflation Polarization Explorer (PIPER) observatory. The goal of this balloon mission is to measure the primordial gravitational waves that should exist if the theory of cosmological inflation is correct. At altitude, the ADR will hold the array of transition-edge sensors at 100 mK continuously while periodically rejecting heat to a 1.2 K pumped helium bath. During testing on ground, the array is held at the same temperature but heat is rejected to a 4.2 K helium bath indicating the flexibility in this coolers design.

NLP model based thermoeconomic optimization of vapor compression–absorption cascaded refrigeration system

International Nuclear Information System (INIS)

Jain, Vaibhav; Sachdeva, Gulshan; Kachhwaha, S.S.

2015-01-01

Highlights: • It addresses the size and cost estimation of cascaded refrigeration system. • Cascaded system is a promising decarburizing and energy efficient technology. • Second law analysis is carried out with modified Gouy-Stodola equation. • The total annual cost of plant operation is optimized in present work. - Abstract: This paper addresses the size and cost estimation of vapor compression–absorption cascaded refrigeration system (VCACRS) for water chilling application taking R410a and water–LiBr as refrigerants in compression and absorption section respectively which can help the design engineers in manufacturing and experimenting on such kind of systems. The main limitation in the practical implementation of VCACRS is its size and cost which are optimized in the present work by implementing Direct Search Method in non-linear programming (NLP) mathematical model of VCACRS. The main objective of optimization is to minimize the total annual cost of system which comprises of costs of exergy input and capital costs in monetary units. The appropriate set of decision variables (temperature of evaporator, condenser, generator, absorber, cascade condenser, degree of overlap and effectiveness of solution heat exchanger) minimizes the total annual cost of VCACRS by 11.9% with 22.4% reduction in investment cost at the base case whereas the same is reduced by 7.5% with 11.7% reduction in investment cost with reduced rate of interest and increased life span and period of operation. Optimization results show that the more investment cost in later case is well compensated through the performance and operational cost of the system. In the present analysis, optimum cascade condensing temperature is a strong function of period of operation and capital recovery factor. The cascading of compression and absorption systems becomes attractive for lower rate of interest and increase life span and operational period

The effect of organics on the sorption of cobalt by glacial sand in laboratory batch experiments

International Nuclear Information System (INIS)

Haigh, D.G.; Williams, G.M.; Hooker, P.J.; Ross, C.A.M.; Allen, M.R.; Warwick, P.

1989-01-01

Acetate, EDTA and organic compounds naturally present in groundwater at the Drigg in situ radionuclide migration experimental site, have been studied to assess their effect on the sorption of cobalt by glacial sand in a series of batch experiments. Removing 56% of the natural organic material from the grounwater with DEAE cellulose increased the distribution ratio (R d ) of cobalt by a factor of about two. EDTA had a dramatic effect on the sorption of Co even at low concentrations, reducing the R d by up to two orders of magnitude. At EDTA concentrations greater than 5 mg/l, there was no further reduction in sorption. EDTA was not itself sorbed, but formed a mobile complex with Co. Differences in distribution ratios were observed depending on whether the cobalt was added before or after EDTA. Within the same period of equilibrium, the R d values were higher when cobalt was allowed to equilibrate with the sand before adding EDTA. The desorption of cobalt from the mineral surface may be a rate-limiting step such that equilibrium was not achieved within the 14-day period of these experiments. Acetate had no effect on cobalt sorption in any of the experiments undertaken. This work is part of the Commission Mirage project, Phase 2, research area Geochemistry of actinides and fission products in natural aquifer systems

Prediction of thermophysical properties of mixed refrigerants using artificial neural network

International Nuclear Information System (INIS)

Sencan, Arzu; Koese, Ismail Ilke; Selbas, Resat

2011-01-01

The determination of thermophysical properties of the refrigerants is very important for thermodynamic analysis of vapor compression refrigeration systems. In this paper, an artificial neural network (ANN) is proposed to determine properties as heat conduction coefficient, dynamic viscosity, kinematic viscosity, thermal diffusivity, density, specific heat capacity of refrigerants. Five alternative refrigerants are considered: R413A, R417A, R422A, R422D and R423A. The training and validation were performed with good accuracy. The thermophysical properties of the refrigerants are formulated using artificial neural network (ANN) methodology. Liquid and vapor thermophysical properties of refrigerants with new formulation obtained from ANN can be easily estimated. The method proposed offers more flexibility and therefore thermodynamic analysis of vapor compression refrigeration systems is fairly simplified.

Condensation of nano-refrigerant inside a horizontal tube

Science.gov (United States)

Darzi, Milad; Sadoughi, M. K.; Sheikholeslami, M.

2018-05-01

In this paper, condensing pressure drop of refrigerant-based nanofluid inside a tube is studied. Isobutene was selected as the base fluid while CuO nanoparticles were utilized to prepare nano-refrigerant. However, for the feasibility of nanoparticle dispersion into the refrigerant, Polyester oil (POE) was utilized as lubricant oil and added to the pure refrigerant by 1% mass fraction. Various values of mass flux, vapor quality, concentration of nanoparticle are investigated. Results indicate that adding nanoparticles leads to enhance frictional pressure drop. Nanoparticles caused larger pressure drop penalty at relatively lower vapor qualities which may be attributed to the existing condensation flow pattern such that annular flow is less influenced by nanoparticles compared to intermittent flow regime.

Testosterone sorption and desorption: Effects of soil particle size

Energy Technology Data Exchange (ETDEWEB)

Qi, Yong, E-mail: yqi01@unomaha.edu [Civil Engineering Dept., University of Nebraska-Lincoln at Omaha Campus, Omaha, NE 68182 (United States); Zhang, Tian C. [Civil Engineering Dept., University of Nebraska-Lincoln at Omaha Campus, Omaha, NE 68182 (United States); Ren, Yongzheng [School of Environmental Science and Engineering, Huazhong University of Science and Technology, Wuhan 430074 (China)

2014-08-30

Graphical abstract: - Highlights: • Smaller soil particles have higher sorption and lower desorption rates. • The sorption capacity ranks as clay > silt > sand. • Small particles like clays have less potential for desorption. • Colloids (clays) have high potential to facilitate the transport of hormones in soil–water environments. - Abstract: Soils contain a wide range of particles of different diameters with different mobility during rainfall events. Effects of soil particles on sorption and desorption behaviors of steroid hormones have not been investigated. In this study, wet sieve washing and repeated sedimentation methods were used to fractionate the soils into five ranges. The sorption and desorption properties and related mechanisms of testosterone in batch reactors filled with fractionated soil particles were evaluated. Results of sorption and desorption kinetics indicate that small soil particles have higher sorption and lower desorption rates than that of big ones. Thermodynamic results show the sorption processes are spontaneous and exothermal. The sorption capacity ranks as clay > silt > sand, depending mainly on specific surface area and surface functional groups. The urea control test shows that hydrogen bonding contributes to testosterone sorption onto clay and silt but not on sand. Desorption tests indicate sorption is 36–65% irreversible from clay to sand. Clays have highest desorption hysteresis among these five soil fractions, indicating small particles like clays have less potential for desorption. The results provide indirect evidence on the colloid (clay)-facilitated transport of hormones (micro-pollutants) in soil environments.

Sorption of strontium on bentonites from Slovak deposits

International Nuclear Information System (INIS)

Kufcakova, J.; Galambos, M.; Rajc, P.

2005-01-01

Sorption on bentonite from different Slovak deposits / Jelsovy potok, Kopernica and Lieskove has been investigated under various experimental conditions, such as contact time, pH, sorbate concentrations, presence of complementary cation. The sorption of strontium from aqueous solutions was investigated using a radiometric determination of distribution coefficient, Kd. The individual solutions were labelled with radiotracer. Radiation stability has been investigated, the higher sorption parameters were observed for the irradiated bentonites /tab.l/ , which can be explained by the increase of specific surface and change of solubility of the irradiated samples of bentonite. The presence of complementary cations, Na + , K + , NH 4 + , Ca 2+ , Mg 2+ and Ba 2+ depresses the sorption of Sr on bentonite. In the case of bentonite Kopernica the effectiveness in reducing the sorption of strontium by cations followed the order K + 4 + + 2+ 2+ 2+ . Results indicate that the sorption of Sr + on bentonite will be affected by the presence of high concentrations of various salts in the waste water effluents. (author)

Performance of a Throttle Cycle Refrigerator with Nitrogen-Hydrocarbon and Argon-Hydrocarbon Mixtures

Science.gov (United States)

Venkatarathnam, G.; Senthil Kumar, P.; Srinivasa Murthy, S.

2004-06-01

Throttle cycle refrigerators are a class of vapor compression refrigerators that can provide refrigeration at cryogenic temperatures and operate with refrigerant mixtures. The performance of our prototype refrigerators with nitrogen-hydrocarbon, nitrogen-hydrocarbon-helium and argon-hydrocarbon refrigerant mixtures is presented in this paper.

Sorption of mercury on chemically synthesized polyaniline

International Nuclear Information System (INIS)

Remya Devi, P.S.; Verma, R.; Sudersanan, M.

2006-01-01

Sorption of inorganic mercury (Hg 2+ ) and methyl mercury, on chemically synthesized polyaniline, in 0.1-10N HCl solutions has been studied. Hg 2+ is strongly sorbed at low acidities and the extent of sorption decreases with increase in acidity. The sorption of methyl mercury is very low in the HCl concentration range studied. Sorption of Hg 2+ on polyaniline in 0.1-10N LiCl and H 2 SO 4 solutions has also been studied. The analysis of the data indicates that the sorption of Hg 2+ depends on the degree of protonation of polyaniline and the nature of mercury(II) chloride complexes in solution. X-ray photoelectron spectroscopy analysis (XPS) of polyaniline sorbed with mercury show that mercury is bound as Hg 2+ . Sorbed mercury is quantitatively eluted from polyaniline with 0.5N HNO 3 . Polyaniline can be used for separation and pre-concentration of inorganic mercury from aqueous samples. (author)

Moisture sorption of Thai red curry powder

Directory of Open Access Journals (Sweden)

Sudathip Inchuen

2009-12-01

Full Text Available Moisture sorption study was conducted on Thai red curry powder prepared by two different drying methods, viz. microwave and hot-air drying. Moisture sorption isotherms of the red curry powder at 30 C and water activity in the range of 0.113-0.970 were determined by a static gravimetric method. The isotherms exhibited Type III behaviour. The moisture sorption data were fitted to several sorption models and a non-linear regression analysis method was used to evaluate the constants of the sorption equations. The fit was evaluated using the coefficient of determination (R2, the reduced chi-square (2 and the root mean square error (RMSE. The GAB model followed by the Lewiski-3 model gave the best fit to the experimental data. The monolayer moisture content, taken as the safe minimum moisture level in the red curry powder, was determined using the BET equation and was found to range between 0.080 - 0.085 gram water per gram dry matter.

REFRIGERANT/LUBRICANT MIXTURES: PROBLEMS OF APPLICATION AND PROPERTY RESEARCH

Directory of Open Access Journals (Sweden)

Yu. Semenyuk

2013-10-01

Full Text Available The results and generalizations of thermophysical property research for the refrigerant/lubricant mixtures are summarized. The methodological aspects of the experimental studies of the thermal properties of real working media for vapor compression refrigeration machines and the general principles of the thermodynamic properties simulation for such solutions are analyzed. It is shown that the admixtures of compressor oil in the refrigerant make the efficiency parameters of compressor systems much lower. The question of a selective solubility of the multicomponent refrigerants in compressor oils is discussed.

Influence of some factors on kinetics of boron ions sorption by inorganic anion exchanger of MNG type

International Nuclear Information System (INIS)

Leont'eva, G.V.

1991-01-01

Consideration is given to the influence of particle size of anion exchanger and boron ion concentration on boron sorption from the solution of the following composition (kg/m 3 ): Na + -71.3; K + - 1.9; Ca 2+ - 43.8; Mg 2+ - 5.7; B 2 O 3 -0.32-1.50; Cl - - 204.6, SO 4 2- - 0.02, CO 3 2+ - 0.40; HCO 3 - - 1.74; pH=8.1; density - 1225 kg/m 3 . Increase of dispersivity of ion-exchange material promotes the elevation of sorption rate. Increase of boron ion concentration in the solution leads to exchange capacity growth and reduction of latent period of nucleation; this results to increase of sorption rate

Thermodynamic investigation of a booster-assisted ejector refrigeration system

International Nuclear Information System (INIS)

Zhao, Hongxia; Zhang, Ke; Wang, Lei; Han, Jitian

2016-01-01

Highlights: • COP based on thermal input increases with booster outlet pressure. • Both entrainment ratio and area ratio increase with booster outlet pressure. • COP based on work is larger than compressor-based refrigeration system. • An optimum booster outlet pressure obtains maximum COP based on work. • Exergy destruction occurs mainly in ejector, condenser, evaporator and generator. - Abstract: In order to improve performance of ejector refrigeration system, a booster is added before an ejector to enhance secondary flow pressure, which is called a booster assisted refrigeration system. Based on mass, momentum and energy conservation, a 1D model of ejector for optimal performance prediction was presented and validated with experimental data. A detailed study of working characteristics of the booster assisted ejector refrigeration system was carried out and compared against conventional ejector refrigeration system and compressor based refrigeration system, on the basis of first and second laws of thermodynamics. Effects of booster outlet pressure on COP_t_h based on thermal energy and COP_w based on work input, and also on entrainment ratio and area ratio of ejector were studied. The exergy destruction rates were also computed and analyzed for components of the booster-assisted ejector refrigeration system. Ways to reduce exergy destruction were discussed.

Theoretical research on the performance of the transcritical ejector refrigeration cycle with various refrigerants

International Nuclear Information System (INIS)

Wang, F.; Li, D.Y.; Zhou, Y.

2015-01-01

The transcritical ejector refrigeration cycle (TERC), which has shown an attractive alternative to the ejector refrigeration systems, can better match large variable-temperature heat sources and yields higher COP. In this paper, in order to find a proper working fluid for the TERC, the performance of the TERC with CO_2 and various working fluids with low critical temperatures including R1270, R32, R143a, R125 and R115 are studied and compared. A thermodynamic model for ejector is set up to simulate the ejector by introducing the real properties of refrigerants. The results indicate that R1270 has the highest COP at the same heat source condition and medium working pressures, and is one of environment-friendly working fluids, hence R1270 is the most proper one. The COP of the transcritical cycle is higher than that of the subcritical cycle, and The effective performance coefficient COP_m of the transcritical cycle is also better. When the heater outlet temperature is increased, its system COP_m improves, but its system COP almost does not change. - Highlights: • A thermodynamic model is used to simulate the ejector with real properties. • The performance of the TERC with various refrigerants is compared. • The environment-friendly working fluid of R1270 shows the most proper one. • The COP of the transcritical cycle is higher than that of the subcritical cycle.

Sorption of metaldehyde using granular activated carbon

Directory of Open Access Journals (Sweden)

S. Salvestrini

2017-09-01

Full Text Available In this work, the ability of granular activated carbon (GAC to sorb metaldehyde was evaluated. The kinetic data could be described by an intra-particle diffusion model, which indicated that the porosity of the sorbent strongly influenced the rate of sorption. The analysis of the equilibrium sorption data revealed that ionic strength and temperature did not play any significant role in the metaldehyde uptake. The sorption isotherms were successfully predicted by the Freundlich model. The GAC used in this paper exhibited a higher affinity and sorption capacity for metaldehyde with respect to other GACs studied in previous works, probably as a result of its higher specific surface area and high point of zero charge.

Carbon dioxide sorption on EDTA modified halloysite

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Waszczuk Patrycja

2016-01-01

Full Text Available In this paper the sorption study of CO2 on EDTA surface modified halloysite was conducted. In the paper chemical modification of halloysite from the Dunino deposit (Poland and its influence on sorption of CO2 are presented. A halloysite samples were washed with water-EDTA 1% solution, centrifuged to separate liquid and impurities and dried. The samples were tested for the sorption capacity using a manometric method with pressure up to 3 MPa. A Langmuir adsorption model was fitted to the data. The results showed that EDTA had a limited effect on the increase of sorption potential at low pressure and the samples exhibited similar results to that ones treated solely with the water solution.

Effect of natural organic materials on cadmium and neptunium sorption

International Nuclear Information System (INIS)

Kung, K.S.; Triay, I.R.

1994-01-01

In a batch sorption study of the effect of naturally occurring organic materials on the sorption of cadmium and neptunium on oxides and tuff surfaces, the model sorbents were synthetic goethite, boehmite, amorphous silicon oxides, and a crushed tuff material from Yucca Mountain, Nevada. An amino acid, 3-(3,4-dihydroxypheny)-DL-alanine (DOPA), and an aquatic-originated fulvic material, Nordic aquatic fulvic acid (NAFA), were used as model organic chemicals. Sorption isotherm results showed that DOPA sorption followed the order aluminum oxide > iron oxide > silicon oxide and that the amount of DOAP sorption for a given sorbent increased as the solution pH was raised. The sorption of cadmium and neptunium on the iron oxide was about ten times higher than that on the aluminum oxide. The sorption of cadmium and neptunium on natural tuff material was much lower than that on aluminum and iron oxides. The sorption of cadmium on iron and aluminum oxides was found to be influenced by the presence of DOPA, and increasing the amount of DOPA coating resulted in higher cadmium sorption on aluminum oxide. However, for iron oxide, cadmium sorption decreased with increasing DOPA concentration. The presence of the model organic materials DOPA and NAFA did not affect the sorption of neptunium on tuff material or on the iron and aluminum oxides. Spectroscopic results indicate that cadmium complexes strongly with DOPA. Therefore, the effect of the organic material, DOPA, on the cadmium sorption is readily observed. However, neptunium is possibly complexed weakly with organic material. Thus, DOPA and NAFA have little effect on neptunium sorption on all sorbents selected for study

Sorption to soil, biochar and compost: is prediction to multicomponent mixtures possible based on single sorbent measurements?

Directory of Open Access Journals (Sweden)

Melanie Kah

2018-06-01

Full Text Available Amendment with biochar and/or compost has been proposed as a strategy to remediate soil contaminated with low levels of polycyclic aromatic hydrocarbons. The strong sorption potential of biochar can help sequestering contaminants while the compost may promote their degradation. An improved understanding of how sorption evolves upon soil amendment is an essential step towards the implementation of the approach. The present study reports on the sorption of pyrene to two soils, four biochars and one compost. Detailed isotherm analyzes across a wide range of concentration confirmed that soil amendments can significantly increase the sorption of pyrene. Comparisons of data obtained by a classical batch and a passive sampling method suggest that dissolved organic matter did not play a significant role on the sorption of pyrene. The addition of 10% compost to soil led to a moderate increase in sorption (<2-fold, which could be well predicted based on measurements of sorption to the individual components. Hence, our result suggest that the sorption of pyrene to soil and compost can be relatively well approximated by an additive process. The addition of 5% biochar to soil (with or without compost led to a major increase in the sorption of pyrene (2.5–4.7-fold, which was, however, much smaller than that suggested based on the sorption measured on the three individual components. Results suggest that the strong sorption to the biochar was attenuated by up to 80% in the presence of soil and compost, much likely due to surface and pore blockage. Results were very similar in the two soils considered, and collectively suggest that combined amendments with compost and biochar may be a useful approach to remediate soils with low levels of contamination. Further studies carried out in more realistic settings and over longer periods of time are the next step to evaluate the long term viability of remediation approaches based on biochar amendments.

Refrigeration plants for the SSCL

International Nuclear Information System (INIS)

McAshan, M.; Ganni, V.; Than, R.; Niehaus, T.

1991-03-01

The basic requirements and operating features of the collider cryogenic system have already been described in other publications. The general arrangement of the refrigeration plant and its subsystems is presented, and the issue of how to provide redundancy in the cryogenic system is addressed, and some of the basic features of the refrigeration plants are described. The collider cryogenic system design is not final yet, and this report only reflects the direction and current status of the cryogenic system design

Refrigeration processes a practical handbook on the physical properties of refrigerants and their applications

CERN Document Server

Meacock, H M

1979-01-01

A comprehensive applications-oriented treatment of the subject in two parts. The first part forms a useful introduction to basic principles dealing with the definitions of the physical properties and outlines the method of their calculation. The second part is devoted to calculated data on a range of refrigerants by means of extensive tables and diagrams. The treatment takes the form of a data sheet, one for each of about thirty refrigerants; this data sheet gives the essential information from which close approximations of pressure, temperature, volume and enthalpy can be made for any predict

Cryogen-free dilution refrigerators

International Nuclear Information System (INIS)

Uhlig, K

2012-01-01

We review briefly our first cryogen-free dilution refrigerator (CF-DR) which was precooled by a GM cryocooler. We then show how today's dry DRs with pulse tube precooling have developed. A few examples of commercial DRs are explained and noteworthy features pointed out. Thereby we describe the general advantages of cryogen-free DRs, but also show where improvements are still desirable. At present, our dry DR has a base temperature of 10 mK and a cooling capacity of 700 μW at a mixing chamber temperature of 100 mK. In our cryostat, in most recent work, an additional refrigeration loop was added to the dilution circuit. This 4 He circuit has a lowest temperature of about 1 K and a refrigeration capacity of up to 100 mW at temperatures slightly above 1 K; the dilution circuit and the 4 He circuit can be run separately or together. The purpose of this additional loop is to increase the cooling capacity for experiments where the cooling power of the still of the DR is not sufficient to cool cold amplifiers and cables, e.g. in studies on superconducting quantum circuits or astrophysical applications.

Cryogen-free dilution refrigerators

Science.gov (United States)

Uhlig, K.

2012-12-01

We review briefly our first cryogen-free dilution refrigerator (CF-DR) which was precooled by a GM cryocooler. We then show how today's dry DRs with pulse tube precooling have developed. A few examples of commercial DRs are explained and noteworthy features pointed out. Thereby we describe the general advantages of cryogen-free DRs, but also show where improvements are still desirable. At present, our dry DR has a base temperature of 10 mK and a cooling capacity of 700 μW at a mixing chamber temperature of 100 mK. In our cryostat, in most recent work, an additional refrigeration loop was added to the dilution circuit. This 4He circuit has a lowest temperature of about 1 K and a refrigeration capacity of up to 100 mW at temperatures slightly above 1 K; the dilution circuit and the 4He circuit can be run separately or together. The purpose of this additional loop is to increase the cooling capacity for experiments where the cooling power of the still of the DR is not sufficient to cool cold amplifiers and cables, e.g. in studies on superconducting quantum circuits or astrophysical applications.

Gamma irradiation in the control of pathogenic bacteria in refrigerated ground chicken meat; Irradiacao gama no controle de bacterias patogenicas em carne de frango refrigerada

Energy Technology Data Exchange (ETDEWEB)

Spoto, Marta Helena Fillet; Alcarde, Andre Ricardo; Gurgel, Maria Silvia do Amaral; Blumer, Lucimara; Walder, Julio Marcos Melges; Domarco, Rachel Elisabeth [Centro de Energia Nuclear na Agricultura (CENA), Piracicaba, SP (Brazil). Lab. de Irradiacao de Alimentos e Radioentomologia]. E-mail: aalcarde@cena.usp.br; Gallo, Claudio Rosa [Sao Paulo Univ., Piracicaba, SP (Brazil). Escola Superior de Agricultura Luiz de Queiroz

2000-09-01

This work evaluated the effect of gamma radiation on reducing the population of Staphylococcus aureus, Escherichia coli nd Salmonella typhimurium in ground chicken breast stored under refrigeration. The experiment included a control and 4 doses of gamma radiation ( 2.0, 4.0, 6.0 and 8.0 kGy) along with 5 periods of storage under refrigeration ( 1, 7 14, 21 and 28 days). Samples of ground chicken breast were inoculated with Staphylococcus aureus (ATCC 14458), Escherichia coli (ATCC 11105) and Salmonella typhimurium (ATCC 0626), irradiated at temperatures between 4 and 8 deg C and stored under refrigeration (5 deg C) for 28 days. The increased radiation dose and period of storage under refrigeration caused a reduction of Staphylococcus aureus, Escherichia coli and Salmonella typhimurium populations in the ground chicken breast. Mean radiation D values determined for Staphylococcus aureus and Escherichia coli were 0.41 and 0.72 kGy, respectively. Gamma irradiation was an effective treatment for chicken meat conservation because the radiation dose of 6.0 kGy kept the ground chicken breast within the microbiological limits established by the Brazilian legislation for up to 28 days under refrigeration. (author)

THE RESULTS OF THE STUDY BOILING POINT OUT OZONE-SAFE REFRIGERANT R410A IN THE EVAPORATORS OF REFRIGERATING MACHINES

Directory of Open Access Journals (Sweden)

V. G. Bukin

2012-01-01

Full Text Available The results of experimental research boiling heat transfer of ozone-friendly R410A refrigerant in evaporators machines and the possibility of its use in place of the prohibited refrigerant R22.

Computer model of the refrigeration system of an ice rink

Energy Technology Data Exchange (ETDEWEB)

Teyssedou, G.; Zmeureanu, R. [Concordia Univ., Centre for Building Studies, Montreal, PQ (Canada). Dept. of Building, Civil and Environmental Engineering; Giguere, D. [Natural Resources Canada, Varennes, PQ (Canada). CANMET Energy Technology Centre

2008-07-01

This paper presented a refrigeration system model of an existing ice rink using a component approach. The chillers, the ice-concrete slab and the controller were the 3 main components used in the simulations which were performed using both open and closed loop systems. The simulated ice rink refrigeration system was based on measurements taken in an existing indoor ice rink located in Montreal, Quebec. Measurements of the refrigeration system included electricity demand; heat flux on the ice sheet; exterior air temperature; ice temperature; return brine temperature; brine temperature at the pump; brine temperature at both evaporator exits; and refrigerant temperature and pressure at the expansion and condenser valve exits. Simulation results and measurements were found to be in good agreement. A computer model of the refrigeration system was developed using the TRNSYS 16 program. The refrigeration system was composed of 2 chillers using refrigerant R-22. The impact of heat recovery from the condensers on the energy demand for sanitary water heating was also estimated. The potential reduction of equivalent carbon dioxide emissions was calculated using the total equivalent warming impact (TEWI) criterion in an effort to estimate the refrigeration impact on global warming. 12 refs., 4 tabs., 12 figs.

He3 cryostat

International Nuclear Information System (INIS)

Novichkova, L.G.; Kulikov, Yu.V.; Stashkova, N.M.

1992-01-01

An effective cryostat featuring a one-cycle He 3 refrigerator with a cryosorption pump is described. Gaseous He 3 in contained in a low-pressure vessel having a common wall with a liquid N 2 bath. Due to this, the gas is cooled before sorption and the sorption rate increases approximately by a factor of ten. The cryostat is provided with a needle valve which cuts off the ballast volume of the pipelines from the refrigerator. As a result, the pressure of He 3 vapours increases before condensation and with refrigerator dimensions selected properly, the liquefaction coefficient reaches approximately 80%. Test results of the cryostat and its specifications are presented. (Author)

Technetium sorption by stibnite from natural water

International Nuclear Information System (INIS)

Peretroukhine, V.; Sergeant, C.; Deves, G.; Poulain, S.; Vesvres, M.H.; Thomas, B.; Simonoff, M.

2006-01-01

The sorption of technetium by powdered and polished mineral stibnite Sb 2 S 3 has been investigated in simulated and natural underground waters from the Meuse/Haute-Marne region (France). The sorption by powdered stibnite has been found to be complete under both aerobic and anaerobic conditions in batch experiments. The sorption rate is higher in the absence of oxygen than under aerobic condition. Increasing the temperature from 30 C to 60 C results in a rise of the sorption rate by 9.1 and 27 times under anaerobic and aerobic conditions, respectively. The observed differences in sorption kinetics in the presence and in absence of oxygen are explained by the interaction of oxygen with sulfide ion in aerobic conditions and by the reduction of technetium(VII) by iron(II) and by other impurities present in natural water and in the mineral, and by the subsequent sorption of Tc(IV) on stibnite under anaerobic conditions. The sorption on a polished mineral surface resulted in the formation of a technetium film, probably Tc 2 S 7 , with a thickness of 1-3 μg Tc/cm 2 pH 3-6 and 4-12 μg Tc/cm 2 at 9-12. The simultaneous formation of stibnite colloids with adsorbed technetium occurs at pH 9-12. The study of the technetium film on the mineral by proton induced X-ray emission analysis showed it to be at least one order of magnitude thinner on the SiO 2 impurities than on the main Sb 2 S 3 component and the iron impurities. (orig.)

Sorption of radionuclides by tertiary clays

International Nuclear Information System (INIS)

Wagner, J.F.; Czurda, K.A.

1990-01-01

The sorption capacity of different clay types for some metals (Co, Cs, Sr and Zn), occurring as common radionuclides in radioactive waste deposits, had been analysed by a static (batch technique) and a dynamic method (percolation tests, in which the driving force is a hydraulic gradient). Sorption capacity generally increased with an increasing pH of solution. A decrease of sorption capacity had been observed in the order Zn > Cs ≥ Co > Sr for the batch and Cs > Zn > Sr > Co for the percolation tests. Clay marls showed a distinctly higher sorption respectively retention capacity as pure clays. Sorption capacity depends on solution parameters like type and concentration of radionuclide, pH, salt concentration, etc., and on rock parameters like mineral content (e.g. swelling clay minerals and carbonates), organic material, rock pH, micro fabric, etc. A third parameter of great influence is the contact time between clay and solution. The adsorption isotherms reflect two different adsorption mechanisms: a very rapid adsorption (a few minutes) on the external surfaces of clay minerals and a slow adsorption process (weeks and longer), due to the diffusion of metal ions into the interlayer space of clay minerals. 12 refs., 9 figs., 1 tab

Magnetic refrigeration--towards room-temperature applications

International Nuclear Information System (INIS)

Brueck, E.; Tegus, O.; Li, X.W.; Boer, F.R. de; Buschow, K.H.J.

2003-01-01

Modern society relies very much on readily available cooling. Magnetic refrigeration based on the magneto-caloric effect (MCE) has become a promising competitive technology for the conventional gas-compression/expansion technique in use today. Recently, there have been two breakthroughs in magnetic-refrigeration research: one is that American scientists demonstrated the world's first room-temperature, permanent-magnet, magnetic refrigerator; the other one is that we discovered a new class of magnetic refrigerant materials for room-temperature applications. The new materials are manganese-iron-phosphorus-arsenic (MnFe(P,As)) compounds. This new material has important advantages over existing magnetic coolants: it exhibits a huge MCE, which is larger than that of Gd metal; and its operating temperature can be tuned from about 150 to about 335 K by adjusting the P/As ratio. Here we report on further improvement of the materials by increasing the Mn content. The large entropy change is attributed to a field-induced first-order phase transition enhancing the effect of the applied magnetic field. Addition of Mn reduces the thermal hysteresis, which is intrinsic to the first-order transition. This implies that already moderate applied magnetic fields of below 2 T may suffice

Sorption of fission nuclides on model milk components. I. Sorption of radiostrontium on hydroxyapatite in aqueous solutions

International Nuclear Information System (INIS)

Rosskopfova, O.; Kopunec, R.; Matel, L.; Macasek, F.; Kristin, J.

1999-01-01

Hydroxyapatite, Ca 10 (PO 4 ) 6 (OH) 2 is a mineral widely spread in nature as a main constituent of phosphate rocks, and also as the major inorganic component of bones and teeth. It was found that sorption process occurs by an ion exchange reaction mechanism between strontium ions in solution and calcium ions in apatite. Ca 2+ → Sr 2+ substitution in hydroxyapatite is important since it explains the mechanism of incorporation of beta-active Sr-90 of atomic debris into the human skeletal system. The strontium uptake at 100 grad C is done by adsorption and diffusion while at 25 grad C it is done by the process of adsorption only. The hydroxyapatite was prepared from aqueous solutions and characterized by standard analytical methods. Some samples of hydroxyapatite were modified by heating after its precipitation from aqueous solution. The sample obtained had characteristics of well crystallized stoichiometric hydroxyapatite. Also, commercial hydroxy-apatites were used. Sorption of strontium ions on synthetic hydroxyapatite was examined using batch method and sorption depends on the method of preparation of hydroxyapatite. In generally, sorption of strontium decreases with the increase in the particle size of hydroxyapatite and decreases with the increase in the pH ( hydroxyapatite surface is amphoteric and acts as a buffer in a wide pH range). The sorption of strontium increases with the increase in [Sr 2+ ] or [Ca 2+ ] in solution to ∼ 10 -5 mol · dm -3 for the hydroxyapatite prepared by heating. The experimental data for sorption of strontium has been fitted with Langmuir-adsorption isotherm. (authors)

Isotherm, kinetic, and thermodynamic study of ciprofloxacin sorption on sediments.

Science.gov (United States)

Mutavdžić Pavlović, Dragana; Ćurković, Lidija; Grčić, Ivana; Šimić, Iva; Župan, Josip

2017-04-01

In this study, equilibrium isotherms, kinetics and thermodynamics of ciprofloxacin on seven sediments in a batch sorption process were examined. The effects of contact time, initial ciprofloxacin concentration, temperature and ionic strength on the sorption process were studied. The K d parameter from linear sorption model was determined by linear regression analysis, while the Freundlich and Dubinin-Radushkevich (D-R) sorption models were applied to describe the equilibrium isotherms by linear and nonlinear methods. The estimated K d values varied from 171 to 37,347 mL/g. The obtained values of E (free energy estimated from D-R isotherm model) were between 3.51 and 8.64 kJ/mol, which indicated a physical nature of ciprofloxacin sorption on studied sediments. According to obtained n values as measure of intensity of sorption estimate from Freundlich isotherm model (from 0.69 to 1.442), ciprofloxacin sorption on sediments can be categorized from poor to moderately difficult sorption characteristics. Kinetics data were best fitted by the pseudo-second-order model (R 2  > 0.999). Thermodynamic parameters including the Gibbs free energy (ΔG°), enthalpy (ΔH°) and entropy (ΔS°) were calculated to estimate the nature of ciprofloxacin sorption. Results suggested that sorption on sediments was a spontaneous exothermic process.

Contribution to magnetic refrigeration study at liquid helium study

International Nuclear Information System (INIS)

Lacaze, A.

1985-10-01

An experimental prototype of magnetic refrigerator operates, following a Carnot cycle, with gallium gadolinium garnet, from liquid helium at 4.2 0 K. Analysis of the cyle and heat exchanges allowed to improve performance up to get more than 50% of Carnot yield at 1.8 0 K and nearly 80% at 2.1 0 K. Operation conditions of a regenerator refrigerator between 4 and 20 0 K are studied. The association of a magnetic refrigerator and a gas refrigerator is analyzed. Among different ways to realize the magnetic stage, an active regenerator cycle is chosen. An experimental device is described [fr

Analysis of a combined Rankine-vapour-compression refrigeration cycle

International Nuclear Information System (INIS)

Aphornratana, Satha; Sriveerakul, Thanarath

2010-01-01

This paper describes a theoretical analysis of a heat-powered refrigeration cycle, a combined Rankine-vapour-compression refrigeration cycle. This refrigeration cycle combines an Organic Rankine Cycle and a vapour-compression cycle. The cycle can be powered by low grade thermal energy as low as 60 deg. C and can produce cooling temperature as low as -10 deg. C. In the analysis, two combined Rankine-vapour-compression refrigeration cycles were investigated: the system with R22 and the system with R134a. Calculated COP values between 0.1 and 0.6 of both the systems were found.

Oskarshamn site investigation. Batch experiments of I, Cs, Sr, Ni, Eu, U and Np sorption onto soil from the Laxemar area

Energy Technology Data Exchange (ETDEWEB)

Holgersson, Stellan (Dept. of Chemical and Biochemical Engineering, Nuclear Chemistry, Chalmers Univ. of Technology, Goeteborg (Sweden))

2009-04-15

initially, compared with the natural groundwater, but for Cs the sorption is weaker over the whole sampling period. Results from the batch experiments with gyttja and natural groundwater at 130 days give R{sub a} values that ranges from 3x10-5 (Sr) to 1x10-2 m (Eu). The order of increasing sorption is: Sr, Cs, U, Ni, Np and Eu. For synthetic groundwater the sorption of U is stronger and comparable with Eu. Results from the batch experiments with clay gyttja, type I and natural groundwater at 130 days give R{sub a} values that ranges from 1x10-5 (Sr) to > 1x10-3 m (Eu). The order of increasing sorption is: Sr, Cs, Ni, U, Np and Eu. For synthetic groundwater the sorption of U is stronger, at least initially, comparable with Eu. For Np, on the other hand, the sorption is weaker and comparable with Sr over the whole sampling period. Results from the batch experiments with sand and natural groundwater at 130 days give R{sub a} values that ranges from 1x10-4 (Sr) to 2x10-1 m (Eu). The order of increasing sorption is: Sr, U, Cs, Ni, Np and Eu. For synthetic groundwater, U and Ni sorption is stronger. For Np the sorption is weaker. Results from the batch experiments with clay and natural groundwater at 130 days give R{sub a} values that ranges from 4x10-7 (U) to > 1x10-3 m (Eu). The order of increasing sorption is: U, Sr, Np, Ni, Cs and Eu. For synthetic groundwater, U and Ni sorption is stronger. For Cs the sorption is weaker. Results from the batch experiments with till, type I and natural groundwater at 130 days give R{sub a} values that ranges from 2x10-6 (U) to > 1x10-2 m (Eu). The order of increasing sorption is: U, Sr, Np, Ni, Cs and Eu. For synthetic groundwater, Ni sorption is stronger. Results from the batch experiments with till, type II and natural groundwater at 130 days give R{sub a} values that ranges from 4x10-7 (U) to > 1x10-2 m (Eu). The order of increasing sorption is: U, Np, Sr, Ni, Cs and Eu. For synthetic groundwater, Ni sorption is stronger. Results from the

Sorption-desorption dynamics of radiocaesium in organic matter soils

International Nuclear Information System (INIS)

Valcke, E.; Cremers, A.

1994-01-01

A systematic study has been carried out on the radiocaesium sorption properties of 25 soils (forest, peat) covering organic matter (OM) contents in the range of 10-97%. Predictions are made for radiocaesium partitioning between micaceous Frayed Edge Sites (FES) and regular exchange sites (RES) on the basis of specific radiocaesium interception potentials of the soil and overall exchange capacity. It is shown that for soils with a very high OM content (>80%), significant fractions are present in a readily reversible form in the OM phase. In soils of low-medium OM content (<40%), only a very minor fraction is present in the OM exchange complex. Experimental findings, based on a desorption screening with a variety of desorption agents are in agreement with these predictions. On the basis of a study of sorption kinetics, some additional tools are available for identifying problem soils. In cases of very high OM content, radiocaesium adsorption is completed within hours demonstrating the involvement of the OM sites. In soils for which interception occurs in the FES, sorption continues to proceed for periods of 2-3 weeks. In conclusion, some examples are presented on radiocaesium desorption using ion exchangers as radiocaesium sinks in promoting desorption. For a peaty soil, near quantitative desorption is accomplished. For forest soils with OM contents in a range of 10-40%, fixation levels of 30-50% are demonstrated

3.3. Sorption activity of cross-linked polymers of ethynyl-piperidol

International Nuclear Information System (INIS)

Khalikov, D.Kh.

2012-01-01

The sorption activity of cross-linked polymers of ethynyl-piperidol was studied. The bilirubin sorption was studied as well. The kinetic of bilirubin sorption and human serum albumin at their joint presence in hydrogel solutions was defined. Bilirubin sorption and change of albumin composition was considered. The sorption of middle molecular peptides was considered as well. The sorption of endogenous toxin by means of ethynyl-piperidol polymers was done.

An evaluation on the environmental consequences of residual CFCs from obsolete household refrigerators in China

International Nuclear Information System (INIS)

Zhao Xiangyang; Duan Huabo; Li Jinhui

2011-01-01

Chlorofluorocarbons (CFCs) contained in household refrigerators consist mainly of CFC-11 and CFC-12, which will be eventually released into the environment. Consequentially, environmental releases of these refrigerants will lead to ozone depletion and contribute significantly to the greenhouse effect, if waste refrigerators are not disposed of properly. In the present paper, the potential release of residual CFCs and their substitutes from obsolete household refrigerators in China is examined, and their contributions to ozone depletion and greenhouse effect are compared with those of other recognized ozone-depleting substances (ODS) and greenhouse gases (GHGs). The results imply that annual potential amounts of released residual CFC-11 and CFC-12 will reach their maximums at 4600 and 2300 tons, respectively in 2011, and then decrease gradually to zero until 2020. Meanwhile, the amounts of their most widely used substitutes HCFC-141b and HFC-134a will keep increasing. Subsequently, the contribution ratio of these CFCs and their substitutes to ozone depletion will remain at 25% through 2011, and reach its peak value of 34% by 2018. The contribution to greenhouse effect will reach its peak value of 0.57% by 2010. Moreover, the contribution ratio of these CFCs to the total global release of CFCs will steadily increase, reaching its peak of 15% by 2018. Thus, this period from 2010 to 2018 is a crucial time during which residual CFCs and their substitutes from obsolete household refrigerators in China will contribute significantly to ozone depletion.

Urine storage under refrigeration preserves the sample in chemical, cellularity and bacteriuria analysis of ACS

Directory of Open Access Journals (Sweden)

Karen Cristina Barcellos Ribeiro

2013-12-01

Full Text Available INTRODUCTION: The analysis of urine abnormal constituents and sediment (ACS comprises tests of great diagnostic and prognostic value in clinical practice. When the analysis of ACS cannot be performed within two hours after collection, the sample must be preserved in order to avoid pre-analytical interferences. Refrigeration is the most applied technique due to its cost effectiveness. Moreover, it presents fewer inconveniences when compared to chemical preservation. However, changes in ACS may also occur in samples under refrigeration. OBJECTIVE: To analyze the influence of refrigeration at 2 to 8ºC on the storage of urine samples within 24 hours. MATERIAL AND METHOD: A total of 80 urine samples were selected from patients admitted at Universidade Federal de Juiz de Fora (UFJF university hospital, which were tested for ACS at room temperature and stored under refrigeration for 6, 12 and 24 hours. RESULTS: The results showed that refrigeration proved to be effective when compared to samples kept at room temperature, inasmuch as the physical, chemical, microbial and cellularity features were preserved. Nevertheless, crystalluria was present after a 6- hour storage period. CONCLUSION: The tests revealed that cooling preserved cellularity and chemical characteristics of urine samples for up to 12 hours. Nonetheless, the precipitation of crystals was evident in this storage method. Thus, the possible consequences of storing urine samples for ACS test under these conditions should be included in the analysis report.

Radionuclide sorption on granitic drill core material

International Nuclear Information System (INIS)

Eriksen, T.E.; Locklund, B.

1987-11-01

Distribution ratios were determined for Sr-85, Cs-134 and Eu-152 on crushed granite and fissure coating/filling material from Stripa mines. Measurements were also carried out on intact fissure surfaces. The experimental data for Sr-85, Cs-134 on crushed material can be accomodated by a sorption model based on the assumption that the crushed material consists of porous spheres with outer and inner surfaces available for sorption. In the case of Eu-152 only sorption on the outer surfaces of the crushed material was observed. The absence of sorption on inner surfaces is most probably due to high depletion of the more strongly sorbed Eu-152 in the water phase and very low diffusivity of Eu-152 in the sorbed state. (orig./HP)

Study of sorption of technetium on pyrrhotine

International Nuclear Information System (INIS)

Shen Dong; Fan Xianhua; Su Xiguang; Zeng Jishu

2001-01-01

The sorption behaviors of technetium on pyrrhotine are studied with batch experiment and dilute sulfuric acid is used to dissolve the technetium adsorbed on pyrrhotine. Sorption and desorption experiment are performed under aerobic and anaerobic conditions (inert gas box). The results show that a significant sorption of technetium on pyrrhotine is found under aerobic and anaerobic conditions, and the sorption on the mineral is supposed to be due to the reduction of TcO 4 - to insoluble TcO 2 ·nH 2 O. Desorption process of the sorbed technetium into dilute sulfuric acid is found to be different under aerobic and anaerobic conditions. On addition of H 2 O 2 to the leach solution a sudden increase of the technetium concentration is observed

Recent progress in sorption mechanisms and models

International Nuclear Information System (INIS)

Fedoroff, M.; Lefevre, G.

2005-01-01

Full text of publication follows: Sorption-desorption phenomena play an important role in the migration of radioactive species in surface and underground waters. In order to predict the transport of these species, we need a good knowledge of sorption processes and data, together with reliable models able to be included in transport calculation. Traditional approaches based on experimentally determined distribution coefficients (Kd) and sorption isotherms have a limited predictive capability, since they are very sensitive to the numerous parameters characterizing the solution and the solid. Models based on thermodynamic equilibria were developed to account for the influence these parameters: the ion exchange model and the surface complexation models (2-pK mono-site, 1-pK multi-site, with several different electrostatic models: CCM, DLM, BSM, TLM,...). Although these models are very useful, studies performed in recent years showed that they have important theoretical and experimental limitations, which result in the fact that we must be very careful when we use them for extrapolating sorption data to long term and to large natural systems. Among all problems which can be found are: the possibility to fit a set of experimental data with different models, sometimes bad adequacy with the real sorption processes, some theoretical limitations such as a rigorous definition of reference and standard states in surface equilibria, slow kinetics which prevent from equilibrium achievement, irreversibility, solubility and evolution of solid phases... Through the increase of the number of sensitive spectroscopic methods, we are now able to know more about sorption processes at the atomic scale. Models such as the 1-pK CD-MUSIC model can account for the influence of orientation of the faces of the solid. More and more examples of the influence of this orientation on the sorption properties are known. Calculations performed by 'ab initio' modeling is also useful to predict the

Modelling of a diffusion-sorption experiment on sandstone

International Nuclear Information System (INIS)

Smith, P.A.

1989-11-01

The results of a diffusion-sorption experiment on a sample of Darley Dale sandstone, using simulated groundwater spiked with a mixture of 125 I, 85 Sr and 137 Cs, are modelled by a one-dimensional porous medium approach in which sorption is described by Freundlich isotherms. The governing equations are solved analytically for the special case of a linear isotherm, and numerically using the computer code RANCHDIFF for non-linear isotherms. A set of time-dependent, ordinary differential equations is obtained using the Lagrange interpolation technique and integrated by Gear's variable order predictor-corrector method. It is shown that the sorption behaviour of 85 Sr can be modelled successfully by a linear isotherm, using a sorption parameter consistent with batch-sorption tests. The behaviour of 137 Cs may be modelled by a non-linear isotherm, but the amount of 137 Cs sorbed is less than that anticipated from batch-sorption tests. 125 I is assumed to be non-sorbing and is used to determine the porosity of the sandstone. (author) 10 figs., 4 tabs., 6 refs

Food Safety Practices Linked with Proper Refrigerator Temperatures in Retail Delis.

Science.gov (United States)

Brown, Laura G; Hoover, Edward Rickamer; Faw, Brenda V; Hedeen, Nicole K; Nicholas, David; Wong, Melissa R; Shepherd, Craig; Gallagher, Daniel L; Kause, Janell R

2018-05-01

Listeria monocytogenes (L. monocytogenes) causes the third highest number of foodborne illness deaths annually. L. monocytogenes contamination of sliced deli meats at the retail level is a significant contributing factor to L. monocytogenes illness. The Centers for Disease Control and Prevention's Environmental Health Specialists Network (EHS-Net) conducted a study to learn more about retail delis' practices concerning L. monocytogenes growth and cross-contamination prevention. This article presents data from this study on the frequency with which retail deli refrigerator temperatures exceed 41°F, the Food and Drug Administration (FDA)-recommended maximum temperature for ready-to-eat food requiring time and temperature control for safety (TCS) (such as retail deli meat). This provision was designed to control bacterial growth in TCS foods. This article also presents data on deli and staff characteristics related to the frequency with which retail delis refrigerator temperatures exceed 41°F. Data from observations of 445 refrigerators in 245 delis showed that in 17.1% of delis, at least one refrigerator was >41°F. We also found that refrigeration temperatures reported in this study were lower than those reported in a related 2007 study. Delis with more than one refrigerator, that lacked refrigerator temperature recording, and had a manager who had never been food safety certified had greater odds of having a refrigerator temperature >41°F. The data from this study suggest that retail temperature control is improving over time. They also identify a food safety gap: some delis have refrigerator temperatures that exceed 41°F. We also found that two food safety interventions were related to better refrigerated storage practices: kitchen manager certification and recording refrigerated storage temperatures. Regulatory food safety programs and the retail industry may wish to consider encouraging or requiring kitchen manager certification and recording refrigerated

Applications of magnetic refrigeration and its assessment. A feasibility study - Final report

Energy Technology Data Exchange (ETDEWEB)

Kitanovski, A.; Diebold, M.; Vuarnoz, D.; Gonin, C.; Egolf, P. W.

2008-04-15

Magnetic refrigeration has the potential to replace conventional refrigeration systems - with often problematic refrigerants - in several niche markets or even some main markets of the refrigeration domain. Based on this insight the Swiss Federal Office of Energy has asked a division of the University of Applied Sciences of Western Switzerland (HEIG-VD) in Yverdon-les-Bains to list all possible refrigeration technologies and to evaluate the potential of magnetic refrigeration for these specific applications. The HEIG-VD researchers have developed a calculation tool to determine the coefficient of performance (COP) value and the exergy efficiency as a function of the magnetic field strength and the rotation frequency of a rotary type of magnetic refrigerator. The considered machine design is based on a patent, which was deposited by these scientists. Based on this work, it is found that especially two applications are very interesting for a closer investigation: the household refrigerator without a freezing compartment and the central chilling unit, which may be of large size. In the domains of refrigeration, where magnetic refrigeration could be successfully applied, the costs for magnetic refrigeration machines would be a little higher than those of the conventional ones. On the other hand the study shows possibilities how the magnetic refrigeration machines could reach higher COP values than those of the corresponding gas compression/expansion machines. Therefore, for magnetic refrigeration one may assume lower costs of operation. For large systems - as e.g. chiller units - it should be studied, if superconducting magnets could be economically applied. (author)

Radionuclide sorption from the safety evaluation perspective

International Nuclear Information System (INIS)

1992-01-01

Research and development directed towards the assessment of the long-term performance of radioactive waste disposal systems has been recognised as a priority area with a strong need for international co-operation and co-ordination. The ultimate aims is to promote the quality and credibility of safety assessment techniques for radioactive waste disposal. Sorption in the geosphere is one of the key processes for retarding the transport of radionuclide from the underground disposal facility to the biosphere. In many cases, sorption in the near field and in the biosphere is also important. A workshop, organised to favor discussion around a small number of invited papers, was held in October 1991: - to evaluate critically the way sorption processes are incorporated in performance assessment models; - to identify open issues of high priority, and; - to propose future activities to resolve these issues. These proceedings reproduce the invited papers and the conclusions and recommendations adopted by the workshop. Eight papers are in the INIS SCOPE. The main subjects studied are: sorption database comparison, sorption database development and three case studies, experimental techniques, adsorption models

Sorption and diffusion of Cs and I in concrete

International Nuclear Information System (INIS)

Andersson, K.; Torstenfelt, B.; Allard, B.

1983-01-01

Concrete has been suggested as a possible encapsulation material for long-term storage of low and medium level radioactive waste. At an underground storage of concrete encapsulated waste, a slow release of radioactive elements into the groundwater by diffusion through the concrete must be considered in the safety analysis. The diffusion may be delayed by sorption reactions on the solid. A wide range of long-lived radionuclides may be present in the low and medium level radioactive waste. Here, the sorption and diffusion of iodide and cesium on slag cement paste and concrete has been studied. The influence of four different water phases (pore water, groundwater, Baltic Sea water and sea water) as well as the influence of some added species (carbonate, sulphate and magnesium) has been investigated. A significant sorption of iodide on cement paste in contact with pore water was observed, indicating that the diffusion may be expected to be retarded in this medium. For cesium the highest sorption was found for concrete and groundwater. This means that the sorption increases as the concrete is weathered. Low or insignificant sorption was found for the cement paste, indicating that the ballast is responsible for the Cs-sorption. Carbonatization enhances the Cs-sorption by about a factor of 3. The diffusivity of Cs in concrete and cement paste was determined to between 2x10 - 14 and 8x10 - 14 m 2 /s in pore water (where an insignificant sorption was observed). The choice of ballast as well as addition of suitable getters with high sorption of the long-lived radionuclides might decrease the mass transfer rate through the cement. (Authors)

Sorption of a nonionic surfactant Tween 80 by minerals and soils

Energy Technology Data Exchange (ETDEWEB)

Kang, Soyoung, E-mail: soyoung@pusan.ac.kr; Jeong, Hoon Young, E-mail: hjeong@pusan.ac.kr

2015-03-02

Highlights: • Tween 80 sorption varies significantly among soil minerals. • Sorption mechanisms and atomic compositions explain to mineral-specific sorption. • Clay minerals and SOM in soils are the key contributors to Tween 80 sorption. • Hysteresis suggests the potential difficulty in removing residual surfactants. - Abstract: Batch experiments were conducted to evaluate Tween 80 sorption by oxides, aluminosilicates, and soils. For oxides, the sorption by silica and alumina follow linear isotherms, and that by hematite follows a Langmuir isotherm. Considering isotherm type and surface coverage, Tween 80 may partition into the silica/alumina–water interface, whereas it may bind to hematite surface sites. Among aluminosilicates, montmorillonite shows the greatest sorption due to the absorption of Tween 80 into interlayers. For other aluminosilicates, it sorbs to surfaces, with the sorption increasing as plagioclase < vermiculite < kaolinite. This results from the relative reactivity among surface sites: ≡NaOH, ≡CaOH << ≡SiOH < ≡AlOH. Experiments using dry- and wet-sieved soils reveal that fine-grained clay minerals, difficult to separate by dry-sieving, contribute significantly to Tween 80 sorption. The greater sorption by untreated soils than H{sub 2}O{sub 2}-treated soils indicates that soil organic matter is a vital sorbent. The sorption hysteresis, contributed to by clay minerals and soil organic matter, is characterized by the greater sorption during the desorption than the sorption stages. This suggests the potential difficulty in removing surfactants from soils. Also, sorption of surfactants can adversely affect surfactant-enhanced remediation by decreasing the aquifer permeability and the availability of surfactants for micellar solubilization.

Designing a magnet for magnetic refrigeration

Energy Technology Data Exchange (ETDEWEB)

Bjoerk, R

2010-03-15

This thesis investigates the design and optimization of a permanent magnet assembly for use in a magnetic refrigeration device. The heart of magnetic refrigeration is the adiabatic temperature change in the magnetocaloric material which is caused by the magnetic field. In order to design an ideal magnet assembly the magnetocaloric materials and the refrigeration process itself and their properties and performance as a function of magnetic field are investigated. For the magnetocaloric materials it is the magnetization, specific heat capacity and adiabatic temperature that are investigated as functions of the magnetic field. Following this the process utilized by a magnetic refrigerator to provide cooling is investigated using a publicly available one dimensional numerical model. This process is called active magnetic regeneration (AMR). The aim is to determine the performance of the AMR as a function of the magnetic field in order to learn the properties of the optimal magnet assembly. The performance of the AMR as a function of the synchronization and width of the magnetic field with respect to the AMR cycle, the ramp rate and maximum value of the magnetic field are investigated. Other published magnet designs used in magnetic refrigeration devices are also evaluated, using a figure of merit based on the properties of the investigated magnetocaloric materials, to learn the properties of the best magnet designs to date. Following this investigation the Halbach cylinder, which is a hollow permanent magnet cylinder with a rotating remanent flux density, is investigated in detail as it forms the basis of many magnet designs used in magnetic refrigeration. Here the optimal dimensions of a Halbach cylinder, as well as analytical calculations of the magnetic field for a Halbach cylinder of infinite length, are presented. Once it has been determined which properties are desirable for a magnet used in magnetic refrigeration the design of a new magnet is described. This is

Hydrophilic structures for condensation management in refrigerator appliances

Science.gov (United States)

Kuehl, Steven John; Vonderhaar, John J; Wu, Guolian; Wu, Mianxue

2014-10-21

A refrigerator appliance that includes a freezer compartment having a freezer compartment door, and a refrigeration compartment having at least one refrigeration compartment door. The appliance further includes a mullion with an exterior surface. The mullion divides the compartments and the exterior surface directs condensation toward a transfer point. The appliance may also include a cabinet that houses the compartments and has two sides, each with an exterior surface. Further, at least one exterior surface directs condensation toward a transfer point.

Study of sorption processes of copper on synthetic hydroxyapatite

International Nuclear Information System (INIS)

Rosskopfova, O.; Galambos, M.; Ometakova, J.; Rajec, P.; Caplovicova, M.

2012-01-01

The sorption of copper on synthetic hydroxyapatite was investigated using a batch method and radiotracer technique. The hydroxyapatite sample prepared by a wet precipitation process was of high crystallinity with Ca/P ratio of 1.688. The sorption of copper on hydroxyapatite was pH independent ranging from 4 to 6 as a result of buffering properties of hydroxyapatite. The adsorption of copper was rapid and the percentage of Cu sorption was >98% during the first 15-30 min of the contact time. The experimental data for sorption of copper have been interpreted in the term of Langmuir isotherm. The sorption of Cu 2+ ions was performed by ion-exchange with Ca 2+ cations on the crystal surface of hydroxyapatite under experimental conditions. The competition effect of Zn 2+ , Fe 2+ and Pb 2+ towards Cu 2+ sorption was stronger than that of Co 2+ , Ni 2+ and Ca 2+ ions. The ability of the bivalent cations to depress the sorption of copper on hydroxyapatite was in the following order Pb 2+ > Fe 2+ > Zn 2+ > Co 2+ ∼ Ni 2+ . (author)

Water vapor sorption thermodynamics of the Nafion ionomer membrane.

Science.gov (United States)

Wadsö, Lars; Jannasch, Patric

2013-07-18

The water interactions of polymer electrolyte membranes are of significant interest when these materials are used in, for example, fuel cells. We have therefore studied the sorption thermodynamics of Nafion with a sorption calorimeter that simultaneously measures the sorption isotherm and the mixing (sorption) enthalpy. This unique method is suitable for investigating the sorption thermodynamics of ionic polymers. The measurements were made at 25 °C on a series of samples dried at different temperatures from 25 to 120 °C. The sorption isotherms indicate that the samples dried at 120 °C lost about 0.8 more water molecules per sulfonic group during the drying than did the samples dried at 25 °C, and this result was verified gravimetrically. The mixing enthalpies showed several peaks or plateaus for the samples dried at 60-120 °C. This behavior was seen up to about 2 water molecules per sulfonic group. As these peaks were not directly related to any feature in the sorption isotherm, they probably have their origin in a secondary process, such as a reorganization of the polymer.

Sorption and migration of neptunium in porous sedimentary materials

International Nuclear Information System (INIS)

Tanaka, Tadao; Mukai, Masayuki; Nakayama, Shinichi

2005-01-01

Column migration experiments of neptunium were conducted for porous sedimentary materials: coastal sand, tuffaceous sand, ando soil, reddish soil, yellowish soil and loess, and migration behavior, sorption mechanisms and chemical formation of Np were investigated. The migration behavior of Np in each material was much different each other, due to chemical formation in solution and/or sorption mechanism of Np. Mathematical models of different concepts were applied to the experimental results to interpret the sorption mechanism and the migration behavior. It can be concluded that both of instantaneous equilibrium sorption and sorption-desorption kinetics have to be considered to model the Np migration in sedimentary materials. (author)

Data mining techniques for thermophysical properties of refrigerants

International Nuclear Information System (INIS)

Kuecueksille, Ecir Ugur; Selbas, Resat; Sencan, Arzu

2009-01-01

This study presents ten modeling techniques within data mining process for the prediction of thermophysical properties of refrigerants (R134a, R404a, R407c and R410a). These are linear regression (LR), multi layer perception (MLP), pace regression (PR), simple linear regression (SLR), sequential minimal optimization (SMO), KStar, additive regression (AR), M5 model tree, decision table (DT), M5'Rules models. Relations depending on temperature and pressure were carried out for the determination of thermophysical properties as the specific heat capacity, viscosity, heat conduction coefficient, density of the refrigerants. Obtained model results for every refrigerant were compared and the best model was investigated. Results indicate that use of derived formulations from these techniques will facilitate design and optimize of heat exchangers which is component of especially vapor compression refrigeration system

Differences in sorption behavior of the herbicide 4-chloro-2-methylphenoxyacetic acid on artificial soils as a function of soil pre-aging.

Science.gov (United States)

Waldner, Georg; Friesl-Hanl, Wolfgang; Haberhauer, Georg; Gerzabek, Martin H

The sorption behavior of the herbicide 4-chloro-2-methylphenoxyacetic acid (MCPA) to three different artificial soil mixtures was investigated. Artificial soils serve as model systems for improving understanding of sorption phenomena. The soils consisted of quartz, ferrihydrite, illite, montmorillonite, and charcoal. In a previous study, several selected mixtures had been inoculated with organic matter, and microbial aging (incubation) had been performed for different periods of time (3, 12, and 18 months) before conducting the sorption experiments. The effect of this pre-incubation time on the sorption behavior was determined. Interaction of MCPA with soil surfaces was monitored by aqueous phase sorption experiments, using high-performance liquid chromatography/ultraviolet and in selected cases Fourier-transformed infrared spectroscopy. The sorption behavior showed large differences between differently aged soils; Freundlich and linear sorption model fits (with sorption constants K f , 1/ n exponents, and K d values, respectively) were given for pH = 3 and the unbuffered pH of ∼7. The largest extent of sorption from diluted solutions was found on the surfaces with a pre-incubation time of 3 months. Sorption increased at acidic pH values. Regarding the influence of aging of artificial soils, the following conclusions were drawn: young artificial soils exhibit stronger sorption at lower concentrations, with a larger K f value than aged soils. A correlation with organic carbon content was not confirmed. Thus, the sorption characteristics of the soils are more influenced by the aging of the organic carbon than by the organic carbon content itself.

Study on sorption capacity of synthetic zeolite for simulated nuclide Cs+

International Nuclear Information System (INIS)

Wang Jinming; Yi Facheng

2006-01-01

For the sake of understanding the functionary order of simulated nuclide Cs + and Synthetic Zeolite (ZF), the sorption equilibrium time and sorption capacity of simulated nuclide Cs + on ZF are studied with the intermittence method. The difference of temperature, pH value, Cs + concentration and medium on sorption capacity and sorption ratio are investigated. The results show that the sorption complexion of simulated nuclide Cs + on ZF in the same concentration solution are sorption equilibrium quantity in range of 155-190 mg/g in different temperatures and that in range of 165-190 mg/g in different pH values and that in range of 120-210 mg/g in different media; and changing order of equilibrium adsorption ratio is the same to that of sorption equilibrium quantity, but their changing range are wider than that of sorption equilibrium quantity; equilibrium adsorption quantity in range of 180-380 mg/g in different concentration solutions, and changing order of equilibrium adsorption ratio is opposite to that of sorption equilibrium quantity, and more-over, their changing range are wider than that of the sorption equilibrium quantity. Sorption equilibrium time of simulated nuclide Cs + on ZF is about ten to fifteen days. So the changing range of sorption capacity of simulated nuclide Cs + on ZF with conditions effects is smaller and the sorption equilibrium time is also less and ZF preferably absorbs Cs in radiation wastes and thus consumedly reduces the effect of radwaste on the environment. (authors)

Effects of sorption behaviour on contaminant migration

International Nuclear Information System (INIS)

Melnyk, T.W.

1985-11-01

The effects of sorption behaviour on contaminant migration in groundwater systems are varied. Retardation of migration and dispersive effects can vary widely and contaminant concentration profiles can take a number of different shapes. This report examines the nature of some of these effects, especially those due to sorption behaviours that are dependent on the concentration of the contaminant in the groundwater. The effects are calculated using, in most cases, analytical solutions to the chemical equations imbedded in a simple reaction-cell or box-model transport algorithm. The hydrogeological parameters are held constant, and radioactive decay and hydrodynamic dispersion are excluded. A general discussion of the role of sorption equations in transport modelling is followed by presentation of migration results for a number of models of sorption behaviour varying from linear isotherms, Langmuir, Freundlich and ion-exchange isotherms, to precipitation reactions and multiple-site sorption reactions. The results are compared and general conclusions are drawn about the various migration behaviours calculated. The conclusions are that equilibrium sorption of trace contaminants can be modelled with linear isotherms (constant distribution coefficients or constant retardation factors) but the evaluation and extrapolation of the distribution coefficient are not easy. Nonlinear isotherms lead to unsymmetrical migration fronts. A comparison of Freundlich and linear isotherms is made. Sorption/desorption kinetic factors can be significant on the time scale of laboratory experiments and can cause large dispersive effects. Slow but important reactions can be missed altogether. Precipitation or mineralization behaviour cannot be modelled with constant distribution coefficients. Also, mineralization reactions can be kinetically slow even on the geological time scale. 89 refs

OPTIONS FOR REDUCING REFRIGERANT EMISSIONS FROM SUPERMARKET SYSTEMS

Science.gov (United States)

The report was prepared to assist personnel responsible for the design, construction, and maintenance of retail food refrigeration equipment in making knowledgeable decisions regarding the implementation of refrigerant-emissions-reducing practices and technologies. It characteriz...

Effect of evaporator temperature on vapor compression refrigeration system

Directory of Open Access Journals (Sweden)

Abdullah A.A.A. Al-Rashed

2011-12-01

Full Text Available This paper presents a comparable evaluation of R600a (isobutane, R290 (propane, R134a, R22, for R410A, and R32 an optimized finned-tube evaporator, and analyzes the evaporator effect on the system coefficient of performance (COP. Results concerning the response of a refrigeration system simulation software to an increase in the amount of oil flowing with the refrigerant are presented. It is shown that there is optima of the apparent overheat value, for which either the exchanged heat or the refrigeration coefficient of performance (COP is maximized: consequently, it is not possible to optimize both the refrigeration COP and the evaporator effect. The obtained evaporator optimization results were incorporated in a conventional analysis of the vapor compression system. For a theoretical cycle analysis without accounting for evaporator effects, the COP spread for the studied refrigerants was as high as 11.7%. For cycle simulations including evaporator effects, the COP of R290 was better than that of R22 by up to 3.5%, while the remaining refrigerants performed approximately within a 2% COP band of the R22 baseline for the two condensing temperatures considered.

Water, a Refrigerant (L`eau, un Frigorigène)

DEFF Research Database (Denmark)

Paul, Joachim

2003-01-01

In the light of the ongoing discussions about the availability and the future of synthetic or natural refrigerants "water" is the most attractive fluid for chillers and icemakers because of the low energy demand, the intrinsic safety and the low costs both for the fluid itself and for the install......In the light of the ongoing discussions about the availability and the future of synthetic or natural refrigerants "water" is the most attractive fluid for chillers and icemakers because of the low energy demand, the intrinsic safety and the low costs both for the fluid itself...... since many years any refrigerant with OPD and GWP, Denmark has put up a law in 2001 which includes hefty taxes on HFC. This tax is added to the price of refrigerants and lies between 17 and 44 EURO/kg for the common fluids. The goal of taxation is clear: To make GWP refrigerants unattractive because...... of their price. In conjunction with tax comes a phase-out scenario which shall be effective from 2006. The options for "natural" refrigerants without ODP and GWP are limited to five fluids which are ammonia (toxic), carbon dioxide (very high pressures), hydrocarbons (flammable), air (relatively low efficiencies...

Yucca Mountain Project far-field sorption studies and data needs

International Nuclear Information System (INIS)

Meijer, A.

1990-09-01

Batch sorption experiments in which radionuclides dissolved in groundwaters from Yucca Mountain were sorbed onto samples of crushed tuff have resulted in a substantial database of sorption coefficients for radionuclides of interest to the repository program. Although this database has been useful in preliminary evaluations of Yucca Mountain as a potential site for a nuclear waste repository, the database has limitations that must be addressed before it can be used for performance assessment calculations in support of a license application for a waste repository. The purpose of this paper is to: review the applicability of simple (constant) sorption coefficients in transport calculations; review and evaluate alternative methods for the derivation of sorption coefficients; summarize and evaluate the present YMP sorption database to identify areas of data sufficiency and significant data gaps; summarize our current understanding of pertinent sorption mechanisms and associated kinetic parameters; evaluate the significance to the YMP of potential problems in the experimental determination and field application of sorption coefficients as enumerated by the NRC (Nuclear Regulatory Commission, 1987) in its technical position paper on sorption; formulate and evaluate strategies for the resolution of NRC concerns regarding experimental problems; and formulate a position on the sorption coefficient database and the level of understanding of sorption mechanisms likely to be required in the licensing application. 75 refs., 1 fig., 2 tabs

Refrigeration Cycle Design for Refrigerant Mixtures by Molecular Simulation

Czech Academy of Sciences Publication Activity Database

Smith, W.R.; Francová, Magda; Kowalski, M.; Nezbeda, Ivo

2010-01-01

Roč. 75, č. 4 (2010), s. 383-391 ISSN 0010-0765 R&D Projects: GA AV ČR IAA400720710 Grant - others:NSERC(CA) OGP1041 Institutional research plan: CEZ:AV0Z40720504 Keywords : refrigerants * molecular simulation s * vapor–liquid equilibrium Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 0.853, year: 2010

Sorption of radionuclides on inorganic sorbents

International Nuclear Information System (INIS)

Rajec, P.; Matel, L.

1995-01-01

The sorption of cesium, strontium, plutonium and americium from water solution on natural zeolite, clay minerals, synthetic zeolites and ferrocyanides in silica gel matrix was studied. The same experiments but with synthetic zeolites irradiated by the dose 100 kGy proved no change in sorption properties. 1 tab., 4 refs

Sorption and diffusion of FE(II) in bentonite

International Nuclear Information System (INIS)

Muurinen, A.; Tournassat, C.; Hadi, J.; Greneche, J.-M.

2014-02-01

The iron in the engineering barrier system of a nuclear waste repository interacts via the corrosion process with the swelling clay intended as the buffer material. This interaction may affect the sealing properties of the clay. In the case of iron-bentonite interaction, redox reactions, dissolution/precipitation, the diffusion and sorption are coupled together. In a combined study different processes are difficult to distinguish from each other, and more specific studies are needed for the separate processes. In particular, there is a need for well-controlled diffusion and sorption experiments where iron is kept as Fe(II). In this project, sorption and diffusion of Fe(II) in bentonite have been studied. The experiments were carried out under low-oxygen conditions in an anaerobic glove-box. The radioactive isotope ( 55 Fe) was used as a tracer in the experiments. The sorption experiments were carried out with two batches of purified MX-80 bentonite. One was purified at Bureau de Recherches Geologiques et Minieres, French Geological Survey (BRGM) and the other one at VTT Technical Research Centre of Finland (VTT). Experiments were also carried out with synthetic smectite, which did not include iron, which was prepared at LMPC (ENSC, F 68093 Mulhouse, France). The sorption experiments were carried out in 0.3 M and 0.05 M NaCl solutions as a function of pH, and in 0.3 M NaCl solution buffered at pH 5 as a function of added Fe(II) concentration. The separation of bentonite and solution at the end of the sorption experiment was carried out in the early phase by centrifuging only. In the later phase, ultrafiltering was added in order to improve the separation. The diffusion experiments were carried out in compacted samples prepared from MX-80 purified at VTT and saturated with 0.3 M NaCl at pH 8 and 5. A non-steady-state diffusion experiment method, where the tracer was introduced as an impulse source between two bentonite plugs was used in the measurements

Sorption and diffusion of FE(II) in bentonite

Energy Technology Data Exchange (ETDEWEB)

Muurinen, A. [VTT Technical Research Centre of Finland, Espoo (Finland); Tournassat, C.; Hadi, J. [BRGM, Orleans (France); Greneche, J.-M. [LPCE, Le Mans (France)

2014-02-15

The iron in the engineering barrier system of a nuclear waste repository interacts via the corrosion process with the swelling clay intended as the buffer material. This interaction may affect the sealing properties of the clay. In the case of iron-bentonite interaction, redox reactions, dissolution/precipitation, the diffusion and sorption are coupled together. In a combined study different processes are difficult to distinguish from each other, and more specific studies are needed for the separate processes. In particular, there is a need for well-controlled diffusion and sorption experiments where iron is kept as Fe(II). In this project, sorption and diffusion of Fe(II) in bentonite have been studied. The experiments were carried out under low-oxygen conditions in an anaerobic glove-box. The radioactive isotope ({sup 55}Fe) was used as a tracer in the experiments. The sorption experiments were carried out with two batches of purified MX-80 bentonite. One was purified at Bureau de Recherches Geologiques et Minieres, French Geological Survey (BRGM) and the other one at VTT Technical Research Centre of Finland (VTT). Experiments were also carried out with synthetic smectite, which did not include iron, which was prepared at LMPC (ENSC, F 68093 Mulhouse, France). The sorption experiments were carried out in 0.3 M and 0.05 M NaCl solutions as a function of pH, and in 0.3 M NaCl solution buffered at pH 5 as a function of added Fe(II) concentration. The separation of bentonite and solution at the end of the sorption experiment was carried out in the early phase by centrifuging only. In the later phase, ultrafiltering was added in order to improve the separation. The diffusion experiments were carried out in compacted samples prepared from MX-80 purified at VTT and saturated with 0.3 M NaCl at pH 8 and 5. A non-steady-state diffusion experiment method, where the tracer was introduced as an impulse source between two bentonite plugs was used in the measurements

Industrial applications of refrigeration. General considerations; Applications industrielles du froid. Generalites

Energy Technology Data Exchange (ETDEWEB)

Marvillet, Ch. [Ecole Centrale de Lyon, 69 - Ecully (France); Groupement pour la Recherche sur les Echangeurs Thermiques, GRETh (France)

2001-10-01

The refrigeration process consists in the lowering of the temperature of a product or of a process below the ambient temperature. Thus, the refrigeration process implies a heat absorption process for the production of coldness. Two ways of coldness production are considered: the mechanical refrigeration using compression or absorption cycle machineries, and the cryogenic refrigeration which requires the use of industrial fluids like liquid nitrogen, helium or CO{sub 2}. This article presents the different functions of refrigeration in industrial processes and the effects of temperature on inert or living matter (influence of temperature on the physical properties, thermodynamic state, and physico-chemical transformations of solids, bodies and substances, influence of temperature on the transformation processes of food products, mechanical refrigeration and mastery of fermentation). (J.S.)

Improvement of two-stage GM refrigerator performance using a hybrid regenerator

International Nuclear Information System (INIS)

Ke, G.; Makuuchi, H.; Hashimoto, T.; Onishi, A.; Li, R.; Satoh, T.; Kanazawa, Y.

1994-01-01

To improve the performance of two-stage GM refrigerators, a hybrid regenerator with magnetic materials of Er 3 Ni and ErNi 0.9 Co 0.1 was used in the 2nd stage regenerator because of its large heat exchange capacity. The largest refrigeration capacity achieved with the hybrid regenerator was 0.95W at helium liquefied temperature of 4.2K. This capacity is 15.9% greater than the 0.82W refrigerator with only Er 3 Ni as the 2nd regenerator material. Use of the hybrid regenerator not only increases the refrigeration capacity at 4.2K, but also allows the 4K GM refrigerator to be used with large 1st stage refrigeration capacity, thus making it more practical

Performance of V-type Stirling-cycle refrigerator for different working fluids

Energy Technology Data Exchange (ETDEWEB)

Tekin, Yusuf; Ataer, Omer Ercan [Erciyes University, Engineering Faculty, Mechanical Engineering Department, Melikgazi, 38 039 Kayseri (Turkey)

2010-01-15

The thermodynamic analysis of a V-type Stirling-cycle Refrigerator (VSR) is performed for air, hydrogen and helium as the working fluid and the performance of the VSR is investigated. The V-type Stirling-cycle refrigerator consists of expansion and compression spaces, cooler, heater and regenerator, and it is assumed that the control volumes are subjected to a periodic mass flow. The basic equations of the VSR are derived for per unit crank angle, so time does not appear in the equations. A computer program is prepared in FORTRAN, and the basic equations are solved iteratively. The mass, temperature and density of working fluid in each control volume are calculated for different charge pressures, engine speeds, and for fixed heater and cooler surface temperatures. The work, instantaneous pressure and the COP of the VSR are calculated. The results are obtained for different working fluids, and given by diagrams. (author)

Automated modelling of complex refrigeration cycles through topological structure analysis

International Nuclear Information System (INIS)

Belman-Flores, J.M.; Riesco-Avila, J.M.; Gallegos-Munoz, A.; Navarro-Esbri, J.; Aceves, S.M.

2009-01-01

We have developed a computational method for analysis of refrigeration cycles. The method is well suited for automated analysis of complex refrigeration systems. The refrigerator is specified through a description of flows representing thermodynamic sates at system locations; components that modify the thermodynamic state of a flow; and controls that specify flow characteristics at selected points in the diagram. A system of equations is then established for the refrigerator, based on mass, energy and momentum balances for each of the system components. Controls specify the values of certain system variables, thereby reducing the number of unknowns. It is found that the system of equations for the refrigerator may contain a number of redundant or duplicate equations, and therefore further equations are necessary for a full characterization. The number of additional equations is related to the number of loops in the cycle, and this is calculated by a matrix-based topological method. The methodology is demonstrated through an analysis of a two-stage refrigeration cycle.

Carnot type magnetic refrigeration below 4.2 K - computer simulation

International Nuclear Information System (INIS)

Hashimoto, T.; Numazawa, T.; Maro, T.

1984-01-01

Cooling devices based on a utilization of the Carnot type magnetic refrigeration cycle are usually selected for the temperature range from 20 K to 1.8 K. However, the refrigeration power in the case of such devices is frequently limited by the heat transfer coefficient between the heat source and the magnetic working substance. Thus, in a magnetic refrigerator studied by Delpuech et al. (1981), the refrigeration power is mainly restricted by the heat transfer coefficient in the isothermal magnetization process at 4.2 K. The present investigation is concerned with the development of a method for achieving high refrigeration power on the basis of a study utilizing computer simulation. One of two methods considered for enhancing refrigeration power is related to the change in the magnetic field, while the other method involves an enlargement of the effective area of gadolinium-gallium-garnet (GGG) with the aid of deep grooves in the surface. 6 references

The NEA sorption data base (SDB)

International Nuclear Information System (INIS)

Ruegger, B.; Ticknor, K.

1992-01-01

The current NEA Sorption Data Base is developed to replace the former International Sorption Information Retrieval System (ISIRS) initiated at Pacific Northwest Laboratory and contains about 11,000 distribution coefficients with corresponding experimental condition parameters describing sorption of key nuclides for a large variety of solid and liquid phases. The SDB is designed to run on a micro-computer using the commercially available database software dBASE III Plus. For each recorded sorption experiment, the SDB provides a bibliographical reference, the most complete characterization of the solid and liquid phases available, a description of the experimental conditions and the distribution coefficient or retardation factor for each element studied. When available, parameters such as temperature, initial radionuclide concentration, pH, Eh, contact time, solid to solution ratio, sample origin, oxidation state and type of solution are included. The SDB provides information for a wide variety of rocks or geological materials, buffer backfill candidates, concretes/cements, elements (Am, Cs, Co, I, Np, Pu, Ra, Sr, Se, Tc, U and, to a lesser extent, Ag, Ba, C, Ce, Eu, Fe, Mn, Mo, Na, Nb, Ni, Pd, Pm, Ru, Sb, Sn, Y, Zn, and Zr), or radioisotopes. A compilation of sorption data like SDB provide a readily available source of data for radioactive waste repository performance assessments when site specific data are not available or essential, for example, during a site selection phase. 2 appendices

Sorption of uranium and cesium by Hanford basalts and associated secondary smectite

International Nuclear Information System (INIS)

Ames, L.L.; McGarrah, J.E.; Walker, B.A.; Salter, P.F.

1982-01-01

Three characterized basalts and an associated secondary smectite were used in comparative uranium and cesium sorption studies. Experiments utilizing two synthetic characteristic basalt groundwaters at 23 and 60 0 C allowed comparison of increased temperature and carbonate concentration effects on Cs and U sorption. The sorption data were fitted to the Dubinin-Radushkevich (D-R) isotherm, and loading maxima and energetics derived. An increase in temperature caused a decrease in Cs sorption maxima on all solids from all groundwaters studied and an increase in U sorption maxima, especially from the higher-carbonate-content groundwater. Sorption energies were characteristic of ion exchange for both Cs and U sorption processes. Basalt U sorption maxima were relatively insignificant, but smectite U sorption maxima surpassed Cs sorption maxima in both groundwaters at 60 0 C. The uranyl carbonate complexes thus may be relatively temperature-sensitive. Upon removal of excess Fe-oxides from the secondary smectite, U sorption decreased and the D-R isotherm reverted to a normal Freundlich sorption isotherm. Removal of excess Fe-oxides from the basalts and secondary smectite would probably result in Freundlich sorption isotherms for both Cs and U. (Auth.)

The sorption behaviour of 99Tc on activated carbon

International Nuclear Information System (INIS)

Xia Deying; Zeng Jishu

2004-01-01

The sorption behaviour of 99 Tc on apricot-pit activated carbon with batch experiment is studied. The influence of such factors as sorbent particle size, temperature, pH value on sorption ratio, and the Freundlich sorption isotherms are reported in this paper. (author)

Refrigerator retirement and replacement programs : lessons learned and application to an Ontario wide program

Energy Technology Data Exchange (ETDEWEB)

NONE

2006-05-15

The best practices in refrigerator retirement programs in North America were identified in an effort to develop a concept for an Ontario-wide provincial refrigerator retirement program. The report focused on describing refrigerator retirement programs, namely those programs that focused on getting rid of old secondary refrigerators. The report excluded refrigerator replacement programs, which encourage householders to retire their refrigerators early and replace them with an energy star refrigerator. However, it was noted that in several regions, both replacement and retirement programs are offered at the same time. The report provided background information on energy use by refrigerators as well as refrigerator retirement and replacement programs. Types of refrigerator retirement and replacement programs and the environmental benefits of these programs were also described. The report also addressed the potential energy impact of an Ontario-wide refrigerator retirement program as well as consumer incentive and bounties initiatives to encourage households to retire units. Other topics covered in the report included the design of typical refrigerator retirement and replacement programs; collection and recycling of retired refrigerators; reported costs of refrigerator retirement and replacement programs; as well as marketing and advertising. The role of retailers and manufacturers and reported lessons learned from refrigerator retirement and replacement were also presented. 14 refs., 6 tabs., 6 appendices.

Kinetics of phosphorus sorption in soils in the state of Paraíba¹

Directory of Open Access Journals (Sweden)

Hemmannuella Costa Santos

2011-08-01

Full Text Available The soil P sorption capacity has been studied for many years, but little attention has been paid to the rate of this process, which is relevant in the planning of phosphate fertilization. The purpose of this experiment was to assess kinetics of P sorption in 12 representative soil profiles of the State of Paraíba (Brazil, select the best data fitting among four equations and relate these coefficients to the soil properties. Samples of 12 soils with wide diversity of physical, chemical and mineralogical properties were agitated in a horizontal shaker, with 10 mmo L-1 CaCl2 solution containing 6 and 60 mg L-1 P, for periods of 5, 15, 30, 45, 60, 90, 120, 420, 720, 1,020, and 1,440 min. After each shaking period, the P concentration in the equilibrium solution was measured and three equations were fitted based on the Freundlich equation and one based on the Elovich equation, to determine which soil had the highest sorption rate (kinetics and which soil properties correlated to this rate. The kinetics of P sorption in soils with high maximum P adsorption capacity (MPAC was fast for 30 min at the lower initial P concentration (6 mg L-1. No difference was observed between soils at the higher initial P concentration (60 mg L-1. The P adsorption kinetics were positively correlated with clay content, MPAC and the amount of Al extracted with dithionite-citrate-bicarbonate. The data fitted well to Freundlich-based equations equation, whose coefficients can be used to predict P adsorption rates in soils.

β-Zeolite modified by ethylenediamine for sorption of Th(IV)

Energy Technology Data Exchange (ETDEWEB)

Liu, Peng; Wu, Hanyu; Yuan, Ni; Yin, Zhuoxin; Pan, Duoqiang; Wu, Wangsuo [Lanzhou Univ. (China). Radiochemistry Lab.; Ministry of Education, Lanzhou (China). Key Lab. of Special Function Materials and Structure Design

2017-08-01

β-Zeolite-EDA was modified with ethylenediamine (EDA) after synthesized. The synthesized material was characterized and used for removal of Th(IV) from aqueous solutions. The influences of pH, ionic strength, contact time, temperature and humic acid (HA) on Th(IV) sorption onto synthesized β-zeolite-EDA was studied by batch technique. The dynamic process showed that the sorption of Th(IV) onto β-zeolite-EDA matched the pseudo-second-order kinetics model. The sorption of Th(IV) on β-zeolite-EDA was significantly dependent on pH values, the sorption percentage increased markedly at pH 3.5-4.5, and then maintained a steady state as pH values increased. Through simulating the sorption isotherms by Langmuir, Freundlich and Dubini-Radushkevich (D-R) models, it could be seen respectively that the sorption pattern of Th(IV) on β-zeolite-EDA was mainly controlled by surface complexation, and that the sorption processes was endothermic and spontaneous. The presence of HA increased Th(IV) sorption on β-zeolite-EDA.

The estimation of energy efficiency for hybrid refrigeration system

International Nuclear Information System (INIS)

Gazda, Wiesław; Kozioł, Joachim

2013-01-01

Highlights: ► We present the experimental setup and the model of the hybrid cooling system. ► We examine impact of the operating parameters of the hybrid cooling system on the energy efficiency indicators. ► A comparison of the final and the primary energy use for a combination of the cooling systems is carried out. ► We explain the relationship between the COP and PER values for the analysed cooling systems. -- Abstract: The concept of the air blast-cryogenic freezing method (ABCF) is based on an innovative hybrid refrigeration system with one common cooling space. The hybrid cooling system consists of a vapor compression refrigeration system and a cryogenic refrigeration system. The prototype experimental setup for this method on the laboratory scale is discussed. The application of the results of experimental investigations and the theoretical–empirical model makes it possible to calculate the cooling capacity as well as the final and primary energy use in the hybrid system. The energetic analysis has been carried out for the operating modes of the refrigerating systems for the required temperatures inside the cooling chamber of −5 °C, −10 °C and −15 °C. For the estimation of the energy efficiency the coefficient of performance COP and the primary energy ratio PER for the hybrid refrigeration system are proposed. A comparison of these coefficients for the vapor compression refrigeration and the cryogenic refrigeration system has also been presented.

Indirect refrigeration systems with natural refrigerants

DEFF Research Database (Denmark)

Knudsen, Hans Jørgen Høgaard; Christensen, Kim Gardø; Jensen, Per Henrik

1998-01-01

Heat transfer for boiling and condensing carbon dioxide has been investigated.Heat transfer for carbon dioxide evaporating inside pipe has been measured and compared with Shah's correlation. The measured heat transfer coefficient is much higher than the value determined with the correlation.A shell......-and-tube heat exchanger with carbon dioxide on the shell side and flow ice inside the tubes has been used to investigate the heat transfer for condensing carbon dioxide.At leats is mentioned results obtained with a frozen food display case using carbone dioxide as refrigerant....

49 CFR 176.93 - Vehicles having refrigerating or heating equipment.

Science.gov (United States)

2010-10-01

... 49 Transportation 2 2010-10-01 2010-10-01 false Vehicles having refrigerating or heating equipment... Transported on Board Ferry Vessels § 176.93 Vehicles having refrigerating or heating equipment. (a) A transport vehicle fitted with refrigerating or heating equipment using a flammable liquid or Division 2.1...

Experimental studies of Cs, Sr, Ni, and Eu sorption on Na-illite and the modelling of Cs sorption

International Nuclear Information System (INIS)

Poinssot, C.; Baeyens, B.; Bradbury, M.H.

1999-08-01

A natural illite (illite du Puy) was purified and converted to the homo-ionic Na-form. The conditioned Na-illite was characterised in terms of its mineralogy, chemical inventory and physico-chemical properties. The structural formula was determined from energy dispersive spectroscopic analyses (SEM/TEM-EDS) and bulk chemistry measurements. A cation exchange capacity of 127 meq kg -1 was determined by the 22 Na isotope dilution method at neutral pH. The Na-CEC was also measured as a function of pH. The stability of Na-illite as a function of pH in the range between 3 and 6 was investigated. At low pH values partial dissolution of the illite occurs releasing the structural elements Al, Si, Mg, and K into solution. The presence of Ca and Sr in solution was interpreted as being due to desorption from cation exchange sites. All of these elements are also present at neutral pH but at considerably lower levels. Such effects cannot be avoided and must be considered in the interpretation of the sorption measurements. The main focus of the experimental work presented here is on the sorption behaviour of Cs, Sr, Ni and Eu on conditioned Na-illite as a function of NaClO 4 background electrolyte concentration (0.1 and 0.01 M), nuclide concentration and pH in the range between 3 and 11. Sorption edge data (R d versus pH) and sorption isotherms (quantity of nuclide sorbed versus equilibrium nuclide concentration) are presented for these four elements. Prior to beginning these experiments, sorption kinetics were measured. The broad based pool of sorption measurements generated from this work will provide the source data sets for subsequent modelling. So far only the Cs sorption measurements have been modelled. A two site cation exchange model was developed to describe the sorption of Cs over the whole range of experimental conditions. The two site types were termed 'frayed edge sites' (FES, high affinity/low capacity) and 'type II sites' (low affinity/high capacity). Selectivity

Use of thermodynamic sorption models to derive radionuclide Kd values for performance assessment: Selected results and recommendations of the NEA sorption project

Science.gov (United States)

Ochs, M.; Davis, J.A.; Olin, M.; Payne, T.E.; Tweed, C.J.; Askarieh, M.M.; Altmann, S.

2006-01-01

For the safe final disposal and/or long-term storage of radioactive wastes, deep or near-surface underground repositories are being considered world-wide. A central safety feature is the prevention, or sufficient retardation, of radionuclide (RN) migration to the biosphere. To this end, radionuclide sorption is one of the most important processes. Decreasing the uncertainty in radionuclide sorption may contribute significantly to reducing the overall uncertainty of a performance assessment (PA). For PA, sorption is typically characterised by distribution coefficients (Kd values). The conditional nature of Kd requires different estimates of this parameter for each set of geochemical conditions of potential relevance in a RN's migration pathway. As it is not feasible to measure sorption for every set of conditions, the derivation of Kd for PA must rely on data derived from representative model systems. As a result, uncertainty in Kd is largely caused by the need to derive values for conditions not explicitly addressed in experiments. The recently concluded NEA Sorption Project [1] showed that thermodynamic sorption models (TSMs) are uniquely suited to derive K d as a function of conditions, because they allow a direct coupling of sorption with variable solution chemistry and mineralogy in a thermodynamic framework. The results of the project enable assessment of the suitability of various TSM approaches for PA-relevant applications as well as of the potential and limitations of TSMs to model RN sorption in complex systems. ?? by Oldenbourg Wissenschaftsverlag.

Compilation of radionuclide sorption coefficients for performance assessment

International Nuclear Information System (INIS)

Carbol, P.; Engkvist, I.

1997-09-01

The report presents four possible site-specific conditions in Sweden. The different sorption mechanisms applicable to the studied elements together with the K d concept are shortly summarised. The influence of organic substances present in the groundwater on the element's sorption and mobility is also discussed. Criteria for selection of K d values are presented together with sensitivity of the values to pH, E h and salinity. Sorption coefficients are recommended for elements in the repository with half-life above 5.3 years. The elements reviewed are: Cs, Sr, Ra, Ln, Ac, Th, Pa, U, Np, Pu, Am, Cm, Co, Ni, Cd, Zr, Nb, Tc, Pd, Ag, Sn, C, I, Cl, Se and Kr. For every element there is a recommendation of a realistic K d value with an uncertainty limit. The selection is based on experimental investigations or chemical analogues. In some cases few or no K d data were found, and it is recommended that sorption studies be performed on elements such as Cd, Pa, Cm, Zr, Nb, Pd, Ag and Sn. The recommended K d values for the different element's sorption on granitic rock, serve as a guidance of the sorption performance

SolarChill - a solar PV refrigerator without battery

Energy Technology Data Exchange (ETDEWEB)

Pedersen, P.H.; Poulsen, S.; Katic, I. [Danish Technological Inst., Taastrup (Denmark)

2004-07-01

A solar powered refrigerator (SolarChill) has been developed in an international project involving Greenpeace International, GTZ, UNICEF, UNEP, WHO, industrial partners and Danish Technological Institute. The refrigerator is able to operate directly on solar PV panels, without battery or additional electronics, and is therefore suitable for locations where little maintenance and reliable operation is mandatory. The main objective of the SolarChill Project is to help deliver vaccines and refrigeration to the rural poor. To achieve this objective, the SolarChill Project developed - and plans to make freely available a versatile refrigeration technology that is environmentally sound, technologically reliable, and affordable. SolarChill does not use any fluorocarbons in its cooling system or in the insulation. For domestic and small business applications, another type of solar refrigerator is under development. This is an upright type, suitable for cool storage of food and beverages in areas where grid power is non-existent or unstable. The market potential for this type is thus present in industrialised countries as well as in countries under development. The unique feature of SolarChill is that energy is stored in ice instead of in batteries. An ice compartment keeps the cabinet at desired temperatures during the night. The paper describes the product development, possible SolarChill applications and experience with the two types of solar refrigerators, as well as results from the laboratory and field test. (orig.)

Refrigeration Playbook. Heat Reclaim; Optimizing Heat Rejection and Refrigeration Heat Reclaim for Supermarket Energy Conservation

Energy Technology Data Exchange (ETDEWEB)

Reis, Chuck [CTA Architects Engineers, Boise, ID (United States); Nelson, Eric [CTA Architects Engineers, Boise, ID (United States); Armer, James [CTA Architects Engineers, Boise, ID (United States); Johnson, Tim [CTA Architects Engineers, Boise, ID (United States); Hirsch, Adam [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Doebber, Ian [National Renewable Energy Laboratory (NREL), Golden, CO (United States)

2015-03-01

The purpose of this playbook and accompanying spreadsheets is to generalize the detailed CBP analysis and to put tools in the hands of experienced refrigeration designers to evaluate multiple applications of refrigeration waste heat reclaim across the United States. Supermarkets with large portfolios of similar buildings can use these tools to assess the impact of large-scale implementation of heat reclaim systems. In addition, the playbook provides best practices for implementing heat reclaim systems to achieve the best long-term performance possible. It includes guidance on operations and maintenance as well as measurement and verification.

A parasitic magnetic refrigerator for cooling superconducting magnet

International Nuclear Information System (INIS)

Nakagome, H.; Takahashi, M.; Ogiwara, H.

1988-01-01

The application of magnetic refrigeration principle at a liquid helium temperature (4.2K) is very useful for cooling a superconducting magnet for its potential of high efficiency. The magnetic refrigerator equipped with 14 pieces of GGG (gadolinium-gallium-garnet) single crystal unit (30mm in diameter 10mm in length) in the rotating disk operates along the gradient of the magnetic field produced by a racetrack superconducting magnet, whose maximum magnetic field is 4.5 Tesla and the minimum field is 1.1 Tesla. The final goal of their program is to liquefy gaseous helium evaporated from a liquid helium vessel of the racetrack superconducting magnet by the rotating magnetic refrigerator which operates by using the magnetic field of the superconducting magnet. A 0.12W refrigeration power in the 0.72rpm operation has been achieved under condition of 4.2K to 11.5K operation. The helium evaporation rate of this magnet system is estimated as the order of 10mW, and the achieved refrigeration power of 0.12W at 4.2K is sufficient for cooling the superconducting magnet

Competitive sorption of heavy metals by water hyacinth roots.

Science.gov (United States)

Zheng, Jia-Chuan; Liu, Hou-Qi; Feng, Hui-Min; Li, Wen-Wei; Lam, Michael Hon-Wah; Lam, Paul Kwan-Sing; Yu, Han-Qing

2016-12-01

Heavy metal pollution is a global issue severely constraining aquaculture practices, not only deteriorating the aquatic environment but also threatening the aquaculture production. One promising solution is adopting aquaponics systems where a synergy can be established between aquaculture and aquatic plants for metal sorption, but the interactions of multiple metals in such aquatic plants are poorly understood. In this study, we investigated the absorption behaviors of Cu(II) and Cd(II) in water by water hyacinth roots in both single- and binary-metal systems. Cu(II) and Cd(II) were individually removed by water hyacinth roots at high efficiency, accompanied with release of protons and cations such as Ca 2+ and Mg 2+ . However, in a binary-metal arrangement, the Cd(II) sorption was significantly inhibited by Cu(II), and the higher sorption affinity of Cu(II) accounted for its competitive sorption advantage. Ionic exchange was identified as a predominant mechanism of the metal sorption by water hyacinth roots, and the amine and oxygen-containing groups are the main binding sites accounting for metal sorption via chelation or coordination. This study highlights the interactive impacts of different metals during their sorption by water hyacinth roots and elucidates the underlying mechanism of metal competitive sorption, which may provide useful implications for optimization of phytoremediation system and development of more sustainable aquaculture industry. Copyright © 2016 Elsevier Ltd. All rights reserved.

Designing a magnet for magnetic refrigeration

DEFF Research Database (Denmark)

Bjørk, Rasmus

This thesis investigates the design and optimization of a permanent magnet assembly for use in a magnetic refrigeration device. The heart of magnetic refrigeration is the adiabatic temperature change in the magnetocaloric material which is caused by the magnetic field. In order to design an ideal...... magnet assembly the magnetocaloric materials and the refrigeration process itself and their properties and performance as a function of magnetic field are investigated. For the magnetocaloric materials it is the magnetization, specific heat capacity and adiabatic temperature that are investigated...... as a function of the magnetic field in order to learn the properties of the optimal magnet assembly. The performance of the AMR as a function of the synchronization and width of the magnetic field with respect to the AMR cycle, the ramp rate and maximum value of the magnetic field are investigated. Other...

Modelling refrigerant distribution in microchannel evaporators

DEFF Research Database (Denmark)

Brix, Wiebke; Kærn, Martin Ryhl; Elmegaard, Brian

2009-01-01

of the refrigerant distribution is carried out for two channels in parallel and for two different cases. In the first case maldistribution of the inlet quality into the channels is considered, and in the second case a non-uniform airflow on the secondary side is considered. In both cases the total mixed superheat...... out of the evaporator is kept constant. It is shown that the cooling capacity of the evaporator is reduced significantly, both in the case of unevenly distributed inlet quality and for the case of non-uniform airflow on the outside of the channels.......The effects of refrigerant maldistribution in parallel evaporator channels on the heat exchanger performance are investigated numerically. For this purpose a 1D steady state model of refrigerant R134a evaporating in a microchannel tube is built and validated against other evaporator models. A study...

Load leveling on industrial refrigeration systems

Science.gov (United States)

Bierenbaum, H. S.; Kraus, A. D.

1982-01-01

A computer model was constructed of a brewery with a 2000 horsepower compressor/refrigeration system. The various conservation and load management options were simulated using the validated model. The savings available for implementing the most promising options were verified by trials in the brewery. Result show that an optimized methodology for implementing load leveling and energy conservation consisted of: (1) adjusting (or tuning) refrigeration systems controller variables to minimize unnecessary compressor starts, (2) The primary refrigeration system operating parameters, compressor suction pressure, and discharge pressure are carefully controlled (modulated) to satisfy product quality constraints (as well as in-process material cooling rates and temperature levels) and energy evaluating the energy cost savings associated with reject heat recovery, and (4) a decision is made to implement the reject heat recovery system based on a cost/benefits analysis.

Thermal investigations of a room temperature magnetic refrigerator

Energy Technology Data Exchange (ETDEWEB)

Smaili, Arezki; Chiba, Younes [Ecole Nationale Polytechnique d' Alger (Algeria)], email: arezki.smaili@enp.edu.dz

2011-07-01

Magnetic refrigeration is a concept based on the magnetocaloric effect that some materials exhibit when the external magnetic field changes. The aim of this paper is to assess the performance of a numerical model in predicting parameters of an active magnetic regenerator refrigerator. Numerical simulations were conducted to perform a thermal analysis on an active magnetic regenerator refrigerator operating near room temperature with and without applied cooling load. Curves of temperature span, cooling capacity and thermal efficiency as functions of the operating conditions were drawn and are presented in this paper. Results showed that at fixed frequency Ql versus mf has an optimum and COP was increased with cycle frequency values. This study demonstrated that the proposed numerical model could be used to predict parameters of an active magnetic regenerator refrigerator as it provides consistent results.

Power Consumption in Refrigeration Systems - Modeling for Optimization

DEFF Research Database (Denmark)

Hovgaard, Tobias Gybel; Larsen, Lars F. S.; Skovrup, Morten Juel

2011-01-01

Refrigeration systems consume a substantial amount of energy. Taking for instance supermarket refrigeration systems as an example they can account for up to 50−80% of the total energy consumption in the supermarket. Due to the thermal capacity made up by the refrigerated goods in the system...... there is a possibility for optimizing the power consumption by utilizing load shifting strategies. This paper describes the dynamics and the modeling of a vapor compression refrigeration system needed for sufficiently realistic estimation of the power consumption and its minimization. This leads to a non-convex function...... with possibly multiple extrema. Such a function can not directly be optimized by standard methods and a qualitative analysis of the system’s constraints is presented. The description of power consumption contains nonlinear terms which are approximated by linear functions in the control variables and the error...

Helium refrigeration system for BNL colliding beam accelerator

International Nuclear Information System (INIS)

Brown, D.P.; Farah, Y.; Gibbs, R.J.; Schlafke, A.P.; Schneider, W.J.; Sondericker, J.H.; Wu, K.C.

1983-01-01

A Helium Refrigeration System which will supply the cooling required for the Colliding Beam Accelerator at Brookhaven National Laboratory is under construction. Testing of the compressor system is scheduled for late 1983 and will be followed by refrigerator acceptance tests in 1984. The refrigerator has a design capacity of 24.8 kW at a temperature level near 4K while simultaneously producing 55 kW for heat shield loads at 55K. When completed, the helium refrigerator will be the world's largest. Twenty-five oil-injected screw compressors with an installed total of 23,250 horsepower will supply the gas required. One of the unique features of the cycle is the application of three centrifugal compressors used at liquid helium temperature to produce the low temperatures (2.5K) and high flow rates (4154 g/s) required for this service

Toxicity Data to Determine Refrigerant Concentration Limits

Energy Technology Data Exchange (ETDEWEB)

Calm, James M.

2000-09-30

This report reviews toxicity data, identifies sources for them, and presents resulting exposure limits for refrigerants for consideration by qualified parties in developing safety guides, standards, codes, and regulations. It outlines a method to calculate an acute toxicity exposure limit (ATEL) and from it a recommended refrigerant concentration limit (RCL) for emergency exposures. The report focuses on acute toxicity with particular attention to lethality, cardiac sensitization, anesthetic and central nervous system effects, and other escape-impairing effects. It addresses R-11, R-12, R-22, R-23, R-113, R-114, R-116, R-123, R-124, R-125, R-134, R-134a, R-E134, R-141b, R-142b, R-143a, R-152a, R-218, R-227ea, R-236fa, R-245ca, R-245fa, R-290, R-500, R-502, R-600a, R-717, and R-744. It summarizes additional data for R-14, R-115, R-170 (ethane), R-C318, R-600 (n-butane), and R-1270 (propylene) to enable calculation of limits for blends incorporating them. The report summarizes the data a nd related safety information, including classifications and flammability data. It also presents a series of tables with proposed ATEL and RCL concentrations-in dimensionless form and the latter also in both metric (SI) and inch-pound (IP) units of measure-for both the cited refrigerants and 66 zerotropic and azeotropic blends. They include common refrigerants, such as R-404A, R-407C, R-410A, and R-507A, as well as others in commercial or developmental status. Appendices provide profiles for the cited single-compound refrigerants and for R-500 and R-502 as well as narrative toxicity summaries for common refrigerants. The report includes an extensive set of references.

Effect of humic acid on sorption of technetium by alumina

International Nuclear Information System (INIS)

Kumar, S.; Rawat, N.; Kar, A.S.; Tomar, B.S.; Manchanda, V.K.

2011-01-01

Highlights: → Tc sorption on alumina has been studied under aerobic as well anaerobic condition over pH 3-10. → Effect of humic acid on sorption of Tc by alumina has been investigated. → Linear additive modeling and surface complexation modeling were carried out to delineate the role of humic acid in Tc(IV) sorption in ternary system of Tc(IV)-humic acid-alumina. → Sorption of humic acid onto alumina and strong complexation of Tc(IV) with humic acid were found to govern the sorption of Tc(IV) in the ternary system. - Abstract: Sorption of technetium by alumina has been studied in absence as well as in presence of humic acid using 95 Tc m as a tracer. Measurements were carried out at fixed ionic strength (0.1 M NaClO 4 ) under varying pH (3-10) as well as redox (aerobic and reducing anaerobic) conditions. Under aerobic conditions, negligible sorption of technetium was observed onto alumina both in absence and in presence of humic acid. However, under reducing conditions (simulated with [Sn(II)] = 10 -6 M), presence of humic acid enhanced the sorption of technetium in the low pH region significantly and decreased at higher pH with respect to that in absence of humic acid. Linear additive as well as surface complexation modeling of Tc(IV) sorption in presence of humic acid indicated the predominant role of sorbed humic acid in deciding technetium sorption onto alumina.

Displacer Diameter Effect in Displacer Pulse Tube Refrigerator

Science.gov (United States)

Zhu, Shaowei

2017-12-01

Gas driving displacer pulse tube refrigerators are one of the work recovery type of pulse tube refrigerators whose theoretical efficiency is the same as Stirling refrigerators'. Its cooling power is from the displacement of the displacer. Displace diameter, rod diameter and pressure drop of the regenerator influence the displacement, which are investigated by numerical simulation. It is shown that the displacement ratio of the displacer over the piston is almost not affected by the displacer diameter at the same rod diameter ratio, or displacer with different diameters almost has the same performance.

Being everything to anyone: Applicability of thermoacoustic technology in the commercial refrigeration market

Science.gov (United States)

Poese, Matthew E.; Smith, Robert W. M.; Garrett, Steven L.

2005-09-01

This talk will compare electrodynamically driven thermoacoustic refrigeration technology to some common implementations of low-lift vapor-compression technology. A rudimentary explanation of vapor-compression refrigeration will be presented along with some of the implementation problems faced by refrigeration engineers using compressor-based systems. These problems include oil management, compressor slugging, refrigerant leaks and the environmental impact of refrigerants. Recently, the method of evaluating this environmental impact has been codified to include the direct effects of the refrigerants on global warming as well as the so-called ``indirect'' warming impact of the carbon dioxide released during the generation (at the power plant) of the electrical power consumed by the refrigeration equipment. It is issues like these that generate commercial interest in an alternative refrigeration technology. However, the requirements of a candidate technology for adoption in a mature and risk-averse commercial refrigeration industry are as hard to divine as they are to meet. Also mentioned will be the state of other alternative refrigeration technologies like free-piston Stirling, thermoelectric and magnetocaloric as well as progress using vapor compression technology with alternative refrigerants like hydrocarbons and carbon dioxide.

Computer simulation of molecular sorption in zeolites

International Nuclear Information System (INIS)

Calmiano, Mark Daniel

2001-01-01

The work presented in this thesis encompasses the computer simulation of molecular sorption. In Chapter 1 we outline the aims and objectives of this work. Chapter 2 follows in which an introduction to sorption in zeolites is presented, with discussion of structure and properties of the main zeolites studied. Chapter 2 concludes with a description of the principles and theories of adsorption. In Chapter 3 we describe the methodology behind the work carried out in this thesis. In Chapter 4 we present our first computational study, that of the sorption of krypton in silicalite. We describe work carried out to investigate low energy sorption sites of krypton in silicalite where we observe krypton to preferentially sorb into straight and sinusoidal channels over channel intersections. We simulate single step type I adsorption isotherms and use molecular dynamics to study the diffusion of krypton and obtain division coefficients and the activation energy. We compare our results to previous experimental and computational studies where we show our work to be in good agreement. In Chapter 5 we present a systematic study of the sorption of oxygen and nitrogen in five lithium substituted zeolites using a transferable interatomic potential that we have developed from ab initio calculations. We show increased loading of nitrogen compared to oxygen in all five zeolites studied as expected and simulate adsorption isotherms, which we compare to experimental and simulated data in the literature. In Chapter 6 we present work on the sorption of ferrocene in the zeolite NaY. We show that a simulated, low energy sorption site for ferrocene is correctly located by comparing to X-ray powder diffraction results for this same system. The thesis concludes with some overall conclusions and discussion of opportunities for future work. (author)

Migration and sorption phenomena in packaged foods.

Science.gov (United States)

Gnanasekharan, V; Floros, J D

1997-10-01

Rapidly developing analytical capabilities and continuously evolving stringent regulations have made food/package interactions a subject of intense research. This article focuses on: (1) the migration of package components such as oligomers and monomers, processing aids, additives, and residual reactants in to packaged foods, and (2) sorption of food components such as flavors, lipids, and moisture into packages. Principles of diffusion and thermodynamics are utilized to describe the mathematics of migration and sorption. Mathematical models are developed from first principles, and their applicability is illustrated using numerical simulations and published data. Simulations indicate that available models are system (polymer-penetrant) specific. Furthermore, some models best describe the early stages of migration/sorption, whereas others should be used for the late stages of these phenomena. Migration- and/or sorption-related problems with respect to glass, metal, paper-based and polymeric packaging materials are discussed, and their importance is illustrated using published examples. The effects of migrating and absorbed components on food safety, quality, and the environment are presented for various foods and packaging materials. The impact of currently popular packaging techniques such as microwavable, ovenable, and retortable packaging on migration and sorption are discussed with examples. Analytical techniques for investigating migration and sorption phenomena in food packaging are critically reviewed, with special emphasis on the use and characteristics of food-simulating liquids (FSLs). Finally, domestic and international regulations concerning migration in packaged foods, and their impact on food packaging is briefly presented.

Sorption behaviour of well-defined oxidation states

International Nuclear Information System (INIS)

Allard, B.; Olofsson, U.; Torstenfelt, B.; Kipatsi, H.

1983-05-01

The sorption of the actinides Am(III), Th(IV), Np(V), Pa(V), U(VI) and Pu has been studied as a function of pH (2-12) for two nuclide concentrations (10 -7 -10 -9 M) (only one for Pa and U) in the systems Al 2 0 3 - 0.01 M NaCl0 4 and Si0 2 - 0.01 M NaCl0 4 . Distribution coefficients have been determined by a batch technique after various contact times (6h - 6w) at constant temperature (25degreeC) in systems equilibrated with air. The observed sorption behaviour indicates a predominantly physical adsorption mechanism, where pH of the aqueous phase is the principal chemical parameter of influence. The sorption is highly related to the degree of hydrolysis, with a maximum in the pH-region where neutral species dominate and with a reduction of the sorption under conditions when anionic species (hydroxides or carbonates) would exist in solution. This is particularly the case for U(VI) at pH above 7-8 when anionic carbonate complexes would be formed. Plutonium is predominantly tetravalent under the present conditions, as indicated by the sorption behaviour. (authors)

Refrigeration Performance and Entropy Generation Analysis for Reciprocating Magnetic Refrigerator with Gd Plates

Directory of Open Access Journals (Sweden)

Yonghua You

2018-06-01

Full Text Available In the current work, a novel 2D numerical model of stationary grids was developed for reciprocating magnetic refrigerators, with Gd plates, in which the magneto-caloric properties, derived from the Weiss molecular field theory, were adopted for the built-in energy source of the magneto-caloric effect. The numerical simulation was conducted under the conditions of different structural and operational parameters, and the effects of the relative fluid displacement (φ on the specific refrigeration capacity (qref and the Coefficient of Performance (COP were obtained. Besides the variations of entropy, the generation rate and number were studied and the contours of the local entropy generation rate are presented for discussion. From the current work, it is found that with an increase in φ, both the qref and COP followed the convex variation trend, while the entropy generation number (Ns varied concavely. As for the current cases, the maximal qref and COP were equal to 151.2 kW/m3 and 9.11, respectively, while the lowest Ns was the value of 2.4 × 10−4 K−1. However, the optimal φ for the largest qref and COP, and for the lowest Ns, were inconsistent, thus, some compromises need be made in the optimization of magnetic refrigerators.

OPTIMAL SYSNTHESIS PROCESSES OF LOW-TEMPERATURE CONDENSATION ASSOCIATED OIL GAS PLANT REFRIGERATION SYSTEM

Directory of Open Access Journals (Sweden)

O. Ostapenko

2015-10-01

Full Text Available Design of modern high-efficient systems is a key priority for the Energy Sector of Ukraine. The cooling technological streams of gas and oil refineries, including air coolers, water cooling and refrigeration systems for specific refrigerants are the objectives of the present study. Improvement of the refrigeration unit with refrigerant separation into fractions is mandatory in order to increase cooling capacity, lowering the boiling point of coolant and increasing the coefficient of target hydrocarbons extraction from the associated gas flow. In this paper it is shown that cooling temperature plays significant role in low-temperature condensation process. Two operation modes for refrigeration unit were proposed: permanent, in which the concentration of the refrigerant mixture does not change and dynamic, in which the concentration of refrigerant mixtures depends on the ambient temperature. Based on the analysis of exergy losses the optimal concentration of refrigerant mixtures propane/ethane for both modes of operation of the refrigeration unit has been determined. On the basis of the conducted pinch-analysis the modification of refrigeration unit with refrigerant separation into fractions was developed. Additional recuperative heat exchangers for utilization heat were added to the scheme. Several important measures to increase the mass flow rate of refrigerant through the second section of the refrigeration centrifugal compressor from 22.5 to 25 kg/s without violating the agreed operational mode of the compressor sections were implemented.

Performance characteristics of low global warming potential R134a alternative refrigerants in ejector-expansion refrigeration system

Directory of Open Access Journals (Sweden)

Mishra Shubham

2016-12-01

Full Text Available Performance assessment of ejector-expansion vapor compression refrigeration system with eco-friendly R134a alternative refrigerants (R152a, R1234yf, R600a, R600, R290, R161, R32, and propylene is presented for air-conditioning application. Ejector has been modeled by considering experimental data based correlations of component efficiencies to take care of all irreversibilities. Ejector area ratio has been optimized based on maximum coefficient of performance (COP for typical air-conditioner operating temperatures. Selected refrigerants have been compared based on area ratio, pressure lift ratio, entrainment ratio, COP, COP improvement and volumetric cooling capacity. Effects of normal boiling point and critical point on the performances have been studied as well. Using ejector as an expansion device, maximum improvement in COP is noted in R1234yf (10.1%, which reduces the COP deviation with R134a (4.5% less in basic cycle and 2.5% less in ejector cycle. Hence, R1234yf seems to be best alternative for ejector expansion system due to its mild flammability and comparable volumetric capacity and cooling COP. refrigerant R161 is superior to R134a in terms of both COP and volumetric cooling capacity, although may be restricted for low capacity application due to its flammability.

Performance characteristics of low global warming potential R134a alternative refrigerants in ejector-expansion refrigeration system

Science.gov (United States)

Mishra, Shubham; Sarkar, Jahar

2016-12-01

Performance assessment of ejector-expansion vapor compression refrigeration system with eco-friendly R134a alternative refrigerants (R152a, R1234yf, R600a, R600, R290, R161, R32, and propylene) is presented for air-conditioning application. Ejector has been modeled by considering experimental data based correlations of component efficiencies to take care of all irreversibilities. Ejector area ratio has been optimized based on maximum coefficient of performance (COP) for typical air-conditioner operating temperatures. Selected refrigerants have been compared based on area ratio, pressure lift ratio, entrainment ratio, COP, COP improvement and volumetric cooling capacity. Effects of normal boiling point and critical point on the performances have been studied as well. Using ejector as an expansion device, maximum improvement in COP is noted in R1234yf (10.1%), which reduces the COP deviation with R134a (4.5% less in basic cycle and 2.5% less in ejector cycle). Hence, R1234yf seems to be best alternative for ejector expansion system due to its mild flammability and comparable volumetric capacity and cooling COP. refrigerant R161 is superior to R134a in terms of both COP and volumetric cooling capacity, although may be restricted for low capacity application due to its flammability.

Energy efficient control of a refrigeration plant

DEFF Research Database (Denmark)

Rasmussen, Henrik; Larsen, Lars F. S.

2009-01-01

This paper proposes a novel method for superheat and capacity control of refrigeration systems. The new idea is to control the superheat by the compressor speed and capacity by the refrigerant flow. A new low order nonlinear model of the evaporator is developed and used in a backstepping design...... and the methods are evaluated with respect to energy efficiency....

Effect of prior refrigeration on botulinal outgrowth in perishable canned cured meat when temperature abused.

Science.gov (United States)

Tompkin, R B; Christiansen, L N; Shaparis, A B

1978-01-01

Perishable canned cured meat inoculated with Clostridium botulinum spores was placed at 4.4 or 10 degrees C after manufacture. Spore germination occurred at 10 degrees C. The germinated cell count remained stable over a period of 16 to 18 weeks. During that time period the inhibitory system and residual nitrite descreased. These factors combine to make perishable canned cured meats more prone to spoilage and potential hazard if they are temperature abused after a period of refrigerated storage. PMID:350155

Advanced exergoeconomic analysis of the multistage mixed refrigerant systems

International Nuclear Information System (INIS)

Mehrpooya, Mehdi; Ansarinasab, Hojat

2015-01-01

Highlights: • Advanced exergoeconomic analysis is performed for mixed refrigerant systems. • Cost of investment is divided into avoidable/unavoidable and endogenous/exogenous. • Results show that interactions between the components is not considerable. - Abstract: Advanced exergoeconomic analysis is applied on three multi stage mixed refrigerant liquefaction processes. They are propane precooled mixed refrigerant, dual mixed refrigerant and mixed fluid cascade. Cost of investment and exergy destruction for the components with high inefficiencies are divided into avoidable/unavoidable and endogenous/exogenous parts. According to the avoidable exergy destruction cost in propane precooled mixed refrigerant process, C-2 compressor with 455.5 ($/h), in dual mixed refrigerant process, C-1 compressor with 510.8 ($/h) and in mixed fluid cascade process, C-2/1 compressor with 338.8 ($/h) should be considered first. A comparison between the conventional and advanced exergoeconomic analysis is done by three important parameters: Exergy efficiency, exergoeconomic factor and total costs. Results show that interactions between the process components are not considerable because cost of investment and exergy destruction in most of them are endogenous. Exergy destruction cost of the compressors is avoidable while heat exchangers and air coolers destruction cost are unavoidable. Investment cost of heat exchangers and air coolers are avoidable while compressor’s are unavoidable

The effect of organics on the sorption of cobalt by glacial sand in laboratory experiments

International Nuclear Information System (INIS)

Haigh, G.; Williams, G.M.; Hooker, P.J.; Ross, C.A.M.; Allen, M.R.

1989-02-01

The effect of acetate, EDTA and natural organic compounds in groundwater at Drigg test site, on the sorption of cobalt by glacial sand has been studied in a series of batch experiments. Removing 50% of the organic material from the groundwater with DEAE cellulose increased the distribution ratio (R d ) of cobalt by a factor of about two. The addition of both EDTA and acetate to the sand/water system led to the removal of Ca, Mg, Sr and Ba from solution. Both organic compounds had the effect of reducing the pH and bicarbonated concentrations. EDTA also removed iron from the solution. EDTA reduced the R d for Co by up to 2 orders of magnitude. At EDTA concentrations greater than 5mg/1, there was no further reduction in sorption. EDTA was not itself sorbed, but formed a mobile complex with Co. Within the same period of equilibrium, the R d values were lower when EDTA was allowed to equilibrate with the sand before adding cobalt. The desorption of cobalt from the minerals surface may be a rate limiting step such that equilibrium was not achieved within the 14 day period of these experiments. Acetate had no effect of cobalt sorption. (author)

Analysis of energy saving performance for household refrigerator with thermal storage of condenser and evaporator

International Nuclear Information System (INIS)

Cheng, Wen-long; Ding, Miao; Yuan, Xu-dong; Han, Bing-Chuan

2017-01-01

Highlights: • A novel refrigerator with both HSC and CSE is proposed. • The operational characteristics of novel refrigerator is analyzed. • The comparison of CSE, HSC and DES refrigerators is analyzed. • DES refrigerator has a largest off-time to on-time ratio of 4.3. • DES refrigerator has the best electrical energy saving performance (32%). - Abstract: The heat transfer performances of evaporators and condensers significantly affect the efficiency of household refrigerators. For enhancing heat transfer of the condensers and evaporators, a novel dual energy storage (DES) refrigerator with both heat storage condenser (HSC) and cold storage evaporator (CSE) is proposed. The performance comparison of three kinds of energy storage refrigerators: HSC refrigerator, CSE refrigerator and DES refrigerator is analyzed by establishing dynamic simulation models. According to the simulation results, the DES refrigerator combines the advantage of HSC refrigerator and CSE refrigerator, it has more balanced operational cycle and higher evaporation pressure and temperature. The DES refrigerator shows a best energy saving performance among the three energy storage refrigerators with largest off-time to on-time ratio of 4.3 and the electrical consumption saving can reach 32%, which is greater than the sum (28%) of the other two kinds of energy storage refrigerators.

Cryo-refrigerators for CNS applications

International Nuclear Information System (INIS)

Clausen, J.; Lesser, J.; Sebastianutto, R.

2001-01-01

Cryo-refrigeration plants for cold neutron sources belong to the field of auxiliary plants or utility facilities of the reactor. In general, they are classified as non-nuclear and serve to dissipate the heat generated in the liquid hydrogen or deuterium from moderating the neutrons of the cold neutron source. Cryo-refrigeration plants for the temperature range of 20 K supply either refrigeration at constant temperature by means of evaporating the cryogenic coolant (usually hydrogen) or, as usual with cold sources, in a specific temperature range by means of warming-up the cryogenic coolant (usually helium) in the moderator or heat exchanger (condensation or subcooling of the deuterium). The operator's requirements to a refrigeration plant are, first of all, that the plant adjusts itself - at low-maintenance or maintenance-free - to the various operation modes at best thermodynamic efficiencies and that it offers as much operating convenience and operating safety as possible. Additional requirements are short times for cool-down, capacity adjustment, stand-by operation in order to avoid poisoning of the cold source and further operational requirements. However, these requirements are limited by mechanics, thermodynamics and financial means. For this reason, for each application a technical solution must be found which is optimally adapted to the competing requirements and which is based on a standard product of the manufacturer, if possible. The operator's different requirements have to be taken in account with regard to the design of the plant and choice of the components; economic aspects in addition also have to be considered. Wherever possible, proven standard components should be used. (orig.)

Possibility of using adsorption refrigeration unit in district heating network

Science.gov (United States)

Grzebielec, Andrzej; Rusowicz, Artur; Jaworski, Maciej; Laskowski, Rafał

2015-09-01

Adsorption refrigeration systems are able to work with heat sources of temperature starting with 50 °C. The aim of the article is to determine whether in terms of technical and economic issues adsorption refrigeration equipment can work as elements that produce cold using hot water from the district heating network. For this purpose, examined was the work of the adsorption air conditioning equipment cooperating with drycooler, and the opportunities offered by the district heating network in Warsaw during the summer. It turns out that the efficiency of the adsorption device from the economic perspective is not sufficient for production of cold even during the transitional period. The main problem is not the low temperature of the water supply, but the large difference between the coefficients of performance, COPs, of adsorption device and a traditional compressor air conditioning unit. When outside air temperature is 25 °C, the COP of the compressor type reaches a value of 4.49, whereas that of the adsorption device in the same conditions is 0.14. The ratio of the COPs is 32. At the same time ratio between the price of 1 kWh of electric power and 1 kWh of heat is only 2.85. Adsorption refrigeration equipment to be able to compete with compressor devices, should feature COPads efficiency to be greater than 1.52. At such a low driving temperature and even changing the drycooler into the evaporative cooler it is not currently possible to achieve.

A study of selenium and tin sorption on granite and geothite

International Nuclear Information System (INIS)

Ticknor, K.V.; McMurry, J.

1996-01-01

Sensitivity analyses based on an illustrative performance assessment case study of a disposal concept for nuclear fuel waste have shown that radioisotopes of Se and Sn could have a significant effect on cumulative radioactive dose if they were to be transported through the geosphere without retardation. Static batch sorption methods, coupled with 2 n factorial experimental designs, were used to determine the extent to which Se and Sn can be sorbed by granite and goethite as a function of total dissolved solids concentration, [TDS], natural fulvic acid concentration as dissolved organic carbon, [DOC], pH and, for the studies with Se, the Se concentration, [Se]. Aqueous speciation and the saturation indices of solubility-controlling solid phases were estimated using the speciation code HARPHRQ with the HATCHES thermodynamic database. The experimental results indicated that Se sorption on granite was, low and not affected by changes in [DOC] or [TDS]. Increased [Se] and increased pH decreased sorption. For Se sorption on goethite, the pH range was narrow but indicated that sorption decreased as pH increased. Increased [TDS] and [Se] lowered sorption on goethite, but changes in [DOC] had no effect on sorption. For Sn, increased pH, [TDS] and [DOC] decreased sorption on granite. For Sn sorption on goethite, increased [DOC] resulted in decreased sorption, but differences in [TDS] and pH had little consistent effect on sorption. (orig.)

Experimental measurements and integrated modelling studies of actinide sorption onto cement

International Nuclear Information System (INIS)

Sugiyama, Daisuke; Fujita, Tomonari; Baston, G.M.N.

2003-01-01

An Integrated Cement Sorption Model (ICSM) for actinides onto Ordinary Portland Cement (OPC) is developed. The experimental measurements using the batch sorption technique for actinides onto cement and constituent minerals, which were considered in the modelling calculations, are also described. The actinide elements studied (thorium, uranium, neptunium, plutonium and americium) were strongly sorbed onto OPC. An initial comparison of the experimental data relating the sorption values of actinides onto cement-component phases with those onto OPC is carried out. The results suggest that the Calcium Silicate Hydrate (C-S-H) phases were found to be the most likely candidates to be the dominant-sorbing phases in order to describe the sorption of a actinides onto OPC. An approach to develop the integrated cement sorption model, based on a thermodynamic surface complexation model, is described with discussions on the possible mineralogy and phase distribution of OPC. Another approach than sorption, assuming that co-precipitation on the surface of the cement phase dominates 'sorption', is proposed and discussed. A scoring system is introduced to assess the applicability of the proposed ICSMs. It is suggested that the thermodynamic sorption model is recommended for the sorption of ionic species and the surface co-precipitation model is recommended for the sorption of neutral species though the sorption model is still recommended to be used to model OPC-based systems. (author)

A study of selenium and tin sorption on granite and goethite

International Nuclear Information System (INIS)

Ticknor, K.V.; McMurry, J.

1996-01-01

Sensitivity analyses based on an illustrative performance assessment case study of a disposal concept for nuclear fuel waste have shown that radioisotopes of Se and Sn could have a significant effect on cumulative radioactive dose if they were to be transported through the geosphere without retardation. Static batch sorption methods, coupled with 2 n factorial experimental designs, were used to determine the extent to which Se and Sn can be sorbed by granite and goethite as a function of total dissolved solids concentration, (TDS), natural fulvic acid concentration as dissolved organic carbon, [DOC], pH and, for the studies with Se, the Se concentration, [Se]. Aqueous speciation and the saturation indices of solubility-controlling solid phases were estimated using the speciation code HARPHRQ with the HATCHES thermodynamic database. The experimental results indicated that Se sorption on granite was low and not affected by changes in [DOC] or [TDS]. Increased [Se] and increased pH decreased sorption. For Se sorption on goethite, the pH range was narrow but indicated that sorption decreased as pH increased. Increased [TDS] and [Se] lowered sorption on goethite, but changes in (DOC] had no effect on sorption. For Sn, increased pH, [TDS] and [DOC] decreased sorption on granite. For Sn sorption on goethite, increased [DOC] resulted in decreased sorption, but differences in [TDS] and pH had little consistent effect on sorption. (author)

Quantum heat engines and refrigerators: continuous devices.

Science.gov (United States)

Kosloff, Ronnie; Levy, Amikam

2014-01-01

Quantum thermodynamics supplies a consistent description of quantum heat engines and refrigerators up to a single few-level system coupled to the environment. Once the environment is split into three (a hot, cold, and work reservoir), a heat engine can operate. The device converts the positive gain into power, with the gain obtained from population inversion between the components of the device. Reversing the operation transforms the device into a quantum refrigerator. The quantum tricycle, a device connected by three external leads to three heat reservoirs, is used as a template for engines and refrigerators. The equation of motion for the heat currents and power can be derived from first principles. Only a global description of the coupling of the device to the reservoirs is consistent with the first and second laws of thermodynamics. Optimization of the devices leads to a balanced set of parameters in which the couplings to the three reservoirs are of the same order and the external driving field is in resonance. When analyzing refrigerators, one needs to devote special attention to a dynamical version of the third law of thermodynamics. Bounds on the rate of cooling when Tc→0 are obtained by optimizing the cooling current. All refrigerators as Tc→0 show universal behavior. The dynamical version of the third law imposes restrictions on the scaling as Tc→0 of the relaxation rate γc and heat capacity cV of the cold bath.

Research for Actively Reducing Infrared Radiation by Thermoelectric Refrigerator

Energy Technology Data Exchange (ETDEWEB)

Kim, Hoon; Kim, Kyomin; Kim, Woochul [Yonsei Univ., Seoul (Korea, Republic of)

2017-03-15

We introduced a technology for reducing infrared radiation through the active cooling of hot surfaces by using a thermoelectric refrigerator. Certain surfaces were heated by aerodynamic heating, and the heat generation processes are proposed here. We calculated the temperatures and radiations from surfaces, while using thermoelectric refrigerators to cool the surfaces. The results showed that the contrast between the radiations of certain surfaces and the ambient environments can be removed using thermoelectric refrigerators.

Sorption of fluoroquinolones and sulfonamides in 13 Brazilian soils.

Science.gov (United States)

Leal, Rafael Marques Pereira; Alleoni, Luis Reynaldo Ferracciú; Tornisielo, Valdemar Luiz; Regitano, Jussara Borges

2013-08-01

Animal production is a leading economic activity in Brazil and antibiotics are widely used. However, the occurrence, behavior, and impacts of antibiotics in Brazilian soils are still poorly known. We evaluated the sorption behavior of four fluoroquinolones (norfloxacin, ciprofloxacin, danofloxacin, and enrofloxacin) and five sulfonamides (sulfadiazine, sulfachloropyridazine, sulfamethoxazole, sulfadimidine, and sulfathiazole) in 13 Brazilian soils with contrasting physical, chemical, and mineralogical properties. Fluoroquinolone sorption was very high (Kd≥544 L kg(-1)) whereas sulfonamide sorption ranged from low to high (Kd=0.7-70.1 L kg(-1)), consistent with previous reports in the literature. Soil texture and cation exchange capacity were the soil attributes that most affected sorption. Cation exchange was the most important sorption mechanism for the fluoroquinolones in highly weathered tropical soils, although cation bridging and ion pairing could not be ruled out. Hydrophobic partition played an important role in the sorption of the sulfonamides, but sorption was also affected by non-hydrophobic interactions with organic and/or mineral surfaces. Sorption for both compound classes tended to be higher in soils with high Al and Fe oxihydroxide contents, but they were not correlated with Kd values. No direct effect of soil pH was seen. The fluoroquinolones are not expected to leach even in worst-case scenarios (soils rich in sand and poor in organic carbon), whereas soil attributes dictate leaching potential for the sulfonamides. Copyright © 2013 Elsevier Ltd. All rights reserved.

Development of JAEA sorption database (JAEA-SDB). Update of data evaluation functions and sorption/QA data

International Nuclear Information System (INIS)

Tachi, Yukio; Suyama, Tadahiro; Ochs, Michael; Ganter, Charlotte

2011-03-01

Sorption and diffusion of radionuclides in buffer materials (bentonite) and rocks are the key processes in the safe geological disposal of radioactive waste, because migration of radionuclides in this barrier is expected to be diffusion-controlled and retarded by sorption processes. It is therefore necessary to understand the sorption and diffusion processes and develop database compiling reliable data and mechanistic/predictive models, so that reliable parameters can be set under a variety of geochemical conditions relevant to performance assessment (PA). For this purpose, Japan Atomic Energy Agency (JAEA) has developed databases of sorption and diffusion parameters in buffer materials (bentonite) and rocks. These sorption and diffusion databases (SDB/DDB) were firstly developed as an important basis for the H12 PA of high-level radioactive waste disposal, and have been provided through the Web. JAEA has been continuing to improve and update the SDB/DDB in view of potential future data needs, focusing on assuring the desired quality level and testing the usefulness of the databases for possible applications to PA-related parameter setting. The present report focuses on developing and updating of the sorption database (JAEA-SDB) as basis of integrated approach for PA-related K d setting. This includes an overview of database structure, contents and functions including additional data evaluation function focusing on multi-parameter dependence, operating method, PA-related applications of the web-based JAEA-SDB. K d data and their QA results are updated by focusing our recent activities on the K d setting and mechanistic model development. As a result, 4,250 K d data from 32 references are added, total K d values in the JAEA-SDB are about 28,540. The QA/classified K d data are about 39% for all K d data in JAEA-SDB. The updated JAEA-SDB is expected to make it possible to obtain quick overview of the available data, and to have suitable access to the respective data

Model Based Control of Refrigeration Systems

DEFF Research Database (Denmark)

Larsen, Lars Finn Sloth

for automation of these procedures, that is to incorporate some "intelligence" in the control system, this project was started up. The main emphasis of this work has been on model based methods for system optimizing control in supermarket refrigeration systems. The idea of implementing a system optimizing...... control is to let an optimization procedure take over the task of operating the refrigeration system and thereby replace the role of the operator in the traditional control structure. In the context of refrigeration systems, the idea is to divide the optimizing control structure into two parts: A part...... optimizing the steady state operation "set-point optimizing control" and a part optimizing dynamic behaviour of the system "dynamical optimizing control". A novel approach for set-point optimization will be presented. The general idea is to use a prediction of the steady state, for computation of the cost...

Materials for Room Temperature Magnetic Refrigeration

DEFF Research Database (Denmark)

Hansen, Britt Rosendahl

Magnetic refrigeration is a cooling method, which holds the promise of being cleaner and more efficient than conventional vapor-compression cooling. Much research has been done during the last two decades on various magnetic materials for this purpose and today a number of materials are considered...... candidates as they fulfill many of the requirements for a magnetic refrigerant. However, no one material stands out and the field is still active with improving the known materials and in the search for a better one. Magnetic cooling is based on the magnetocaloric effect, which causes a magnetic material...... to change its temperature when a magnetic field is applied or removed. For room temperature cooling, one utilizes that the magnetocaloric effect peaks near magnetic phase transitions and so the materials of interest all have a critical temperature within the range of 250 – 310 K. A magnetic refrigerant...

Theoretical analysis of ejector refrigeration system performance under overall modes

International Nuclear Information System (INIS)

Chen, Weixiong; Shi, Chaoyin; Zhang, Shuangping; Chen, Huiqiang; Chong, Daotong; Yan, Junjie

2017-01-01

Highlights: • Real gas theoretical model is used to get ejector performance at critical/sub-critical modes. • The model has a better accuracy against the experiment results compared to ideal gas model. • The overall performances of two refrigerants are analyzed based on the parameter analysis. - Abstract: The ejector refrigeration integrated in the air-conditioning system is a promising technology, because it could be driven by the low grade energy. In the present study, a theoretical calculation based on the real gas property is put forward to estimate the ejector refrigeration system performance under overall modes (critical/sub-critical modes). The experimental data from literature are applied to validate the proposed model. The findings show that the proposed model has higher accuracy compared to the model using the ideal gas law, especially when the ejector operates at sub-critical mode. Then, the performances of the ejector refrigeration circle using different refrigerants are analyzed. R290 and R134a are selected as typical refrigerants by considering the aspects of COP, environmental impact, safety and economy. Finally, the ejector refrigeration performance is investigated under variable operation conditions with R290 and R134a as refrigerants. The results show that the R290 ejector circle has higher COP under critical mode and could operate at low evaporator temperature. However, the performance would decrease rapidly at high condenser temperature. The performance of R134a ejector circle is the opposite, with relatively lower COP, and higher COP at high condenser temperature compared to R290.

Compilation of radionuclide sorption coefficients for performance assessment

Energy Technology Data Exchange (ETDEWEB)

Carbol, P.; Engkvist, I. [PI Chemical Consulting HB, Landvetter (Sweden)

1997-09-01

The report presents four possible site-specific conditions in Sweden. The different sorption mechanisms applicable to the studied elements together with the K{sub d} concept are shortly summarised. The influence of organic substances present in the groundwater on the element`s sorption and mobility is also discussed. Criteria for selection of K{sub d} values are presented together with sensitivity of the values to pH, E{sub h} and salinity. Sorption coefficients are recommended for elements in the repository with half-life above 5.3 years. The elements reviewed are: Cs, Sr, Ra, Ln, Ac, Th, Pa, U, Np, Pu, Am, Cm, Co, Ni, Cd, Zr, Nb, Tc, Pd, Ag, Sn, C, I, Cl, Se and Kr. For every element there is a recommendation of a realistic K{sub d} value with an uncertainty limit. The selection is based on experimental investigations or chemical analogues. In some cases few or no K{sub d} data were found, and it is recommended that sorption studies be performed on elements such as Cd, Pa, Cm, Zr, Nb, Pd, Ag and Sn. The recommended K{sub d} values for the different element`s sorption on granitic rock, serve as a guidance of the sorption performance 87 refs, 18 tabs

Sorption isotherms, GAB parameters and isosteric heat of sorption

NARCIS (Netherlands)

Quirijns, E.J.; Boxtel, van A.J.B.; Loon, van W.K.P.; Straten, van G.

2005-01-01

The diffusion-sorption drying model has been developed as a physics-based way to model the decreasing drying rate at low moisture contents. This new model is founded on the existence of different classes of water: free and bound water. The transition between these classes and the corresponding

New sorption-reagent materials for decontamination of liquid radioactive waste

International Nuclear Information System (INIS)

Avramenko, V.A.; Golikov, A.P.; Zheleznov, V.V.; Kaplun, E.V.; Marinin, D.V.; Sokolnitskaya, T.A.

2001-01-01

Full text: Use of selective sorbents in liquid radioactive waste (LRW) management is widely spread in the field of nuclear power objects liquid waste decontamination, since the main objective there is to remove long-lived radionuclides of the nuclear cycle. The latter include, first of all, cesium-137, strontium-90, cobalt-60 and a number of α-irradiators. In this case LRW composition for most of the nuclear power objects is rather simple, except acidic deactivation solutions. At the same time, liquid radioactive wastes of different research centers have a variable chemical and radiochemical composition depending on objectives and tasks of a given center research activities. As a result, application of sorption technologies in such waste decontamination determines special requirements to these sorbents selectivity: a wide spectrum of radionuclides that can be removed and fairly high selectivity enabling to remove radionuclides from solutions of complex chemical composition (containing surfactants, complexing agents etc.). This paper is concerned with studying properties of new materials selective to different radionuclides. These materials are capable to interact with solution components whether already contained in the waste or deliberately added into resulting solution. Such sorption-reagent materials combine universal character of co-precipitation methods with simplicity of sorption methods. In this work we studied sorption-reagent inorganic ion-exchange materials interacting with sulfate-, carbonate-, oxalate-, sulfide-, and permanganate-ions. Insoluble compounds formed as a result of this interaction increase tens- and hundreds-fold the sorption selectivity of different radionuclides - strontium, cobalt, mercury, iron, and manganese as compared to conventional ion-exchange system. By means of X-ray phase analysis, IR-spectroscopy, chemical and radiochemical analysis, we have studied the mechanism of radionuclide sorption on different sorption

SOLAR REFRIGERATING UNIT WITH AN ADSORPTION REACTOR AND EVACUATED TUBE COLLECTORS

Directory of Open Access Journals (Sweden)

M.E. Vieira

1997-09-01

Full Text Available This work presents the principles of operation of a solar refrigerator with the following basic components: a reactor, a set of evacuated tube solar collectors, a condenser, a heat exchanger, and an evaporator. During the heating phase, solar radiation is collected and transferred to the reactor for desorption by a vapor thermal siphon loop. During the cooling phase, heat from the reactor is released to the ambient by a second water vapor loop. Ambient data collected daily during a period of 18 years were divided into hourly values and used to simulate the temperatures of the reactor, which uses salt impregnated with graphite and ammonia, during the adsorption / desorption processes. The results show that the refrigerator operates well in Fortaleza and that better results are expected for the countryside of the state of Ceara. It is concluded that only a high efficiency collector set can be used in the system

Food irradiation combined with refrigeration in food industrial plants

International Nuclear Information System (INIS)

Boisseau, P.

1991-01-01

Food irradiation and refrigeration are both physical treatments used for food preservation. The complementarity of their effects on food is the best reason for their combination. Irradiation is essentially used for disinfestation and refrigeration to protect food against non microbial degradations. Refrigeration and irradiation could be combined for shelf life extension of fresh fruits and vegetables or reduction of microflora in animal products, without loss of quality. Freezing must be combined with ionizing treatments if high doses are necessary as it is the case with destruction of pathogens in meat or food sterilization. Some examples of combination of refrigeration and irradiation are routinely applied in some industrial plants in France but it is expected that more and more combined treatments will be used thanks to research

Kinetic Modelling of the Removal of Multiple Heavy Metallic Ions from Mine Waste by Natural Zeolite Sorption

Directory of Open Access Journals (Sweden)

Amanda L. Ciosek

2017-07-01

Full Text Available This study investigates the sorption of heavy metallic ions (HMIs, specifically lead (Pb2+, copper (Cu2+, iron (Fe3+, nickel (Ni2+ and zinc (Zn2+, by natural zeolite (clinoptilolite. These HMIs are combined in single-, dual-, triple-, and multi-component systems. The batch mode experiments consist of a total initial concentration of 10 meq/L normality for all systems, acidified to a pH of 2 by concentrated nitric (HNO3 acid. A zeolite dosage of 4 g per 100 mL of synthetic nitrate salt aqueous solution is applied, for a contact period of 5 to 180 min. Existing kinetic models on HMIs sorption are limited for multi-component system combinations. Therefore, this study conducts kinetic analysis by both reaction and diffusion models, to quantify the sorption process. The study concludes that the process correlates best with the pseudo-second-order (PSO kinetic model. In the multi-component system combining all five HMIs, the initial sorption rate and theoretical equilibrium capacity are determined as 0.0033 meq/g·min and 0.1159 meq/g, respectively. This provides significant insight into the mechanisms associated with the sorption process, as well as contributing to the assessment of natural zeolite as a sorbent material in its application in industrial wastewater treatment.

Dynamic model of an autonomous solar absorption refrigerator

International Nuclear Information System (INIS)

Ali Fellah; Tahar Khir; Ammar Ben Brahim

2009-01-01

The performance analysis of a solar absorption refrigerator operating in an autonomous way is investigated. The water/LiBr machine satisfies the air-conditioning needs along the day. The refrigerator performances were simulated regarding a dynamic model. For the solar driven absorption machines, two applications could be distinguished. The sun provides the thermal part of the useful energy. In this case, it is necessary to use additional energy as the electric one to activate the pumps, the fans and the control system. On the other hand, the sun provides all the necessary energy. Here, both photovoltaic cells and thermal concentrators should be used. The simulation in dynamic regime of the cycle requires the knowledge of the geometric characteristics of every component as the exchange areas and the internal volumes. Real characteristics of a refrigerator available at the applied thermodynamic research unit (ATRU) at the engineers' national school of Gabes are notified. The development of the thermal and matter balances in every component of the cycle has permitted to simulate in dynamic regime the performances of a solar absorption refrigerator operating with the water/LiBr couple for air-conditioning needs. The developed model could be used to perform intermittent refrigeration cycle autonomously driven. (author)

Mechanism of cesium sorption on potassium titanium hexacyanoferrate

International Nuclear Information System (INIS)

Sun Yongxia; Xu Shiping; Song Chongli

1998-01-01

The mechanism of cesium sorption on potassium titanium hexacyanoferrate is described. The dependence of the sorption speed on temperature, particle granule size, and the stirring speed is studied. The results show that the sorption process is controlled by liquid film diffusion and particle diffusion. An exchange reaction occurs mainly between K + in the exchanger and Cs + in the solution, i.e. potassium titanium hexacyanoferrate, and Cs + of simulated high-level liquid waste

Application of magnetic refrigeration and its assessment - Annual report 2007

Energy Technology Data Exchange (ETDEWEB)

Kitanovski, A.; Vuarnoz, D.; Diebold, M.; Gonin, C.; Egolf, P. W.

2007-07-01

This annual report for the Swiss Federal Office of Energy (SFOE) takes a look at the work done in 2007 at the University of Applied Sciences of Western Switzerland on a project involving refrigeration based on magnetic effects. Possible refrigeration technologies and the evaluation of the potential of magnetic refrigeration are discussed. A calculation tool developed to determine the coefficient of performance (COP) values and the exergy efficiency as a function of magnetic field strength and rotational frequency for rotary types of magnetic refrigerators is introduced. Two applications that are considered to be very interesting for initial research, namely a household refrigerator without a freezing compartment and a large-size central chilling unit are discussed. The COP values of such large-scale systems are commented on. The study of the use of even superconducting magnets is considered as being an economic solution.

Sorption of Europium in zirconium silicate

International Nuclear Information System (INIS)

Garcia R, G.

2004-01-01

Some minerals have the property of sipping radioactive metals in solution, that it takes advantage to manufacture contention barriers that are placed in the repositories of nuclear wastes. The more recent investigations are focused in the development of new technologies guided to the sorption of alpha emissors on minerals which avoid their dispersion in the environment. In an effort to contribute to the understanding of this type of properties, some studies of sorption of Europium III are presented like homologous of the americium, on the surface of zirconium silicate (ZrSiO 4 ). In this work the results of sorption experiences are presented as well as the interpretation of the phenomena of the formation of species in the surface of the zirconium silicate. (Author)

Sorption of radioactive technetium on pyrrhotine

International Nuclear Information System (INIS)

Shen, D.; Fan, X.H.; Su, X.G.; Zeng, J.S.; Dong, Y.

2002-01-01

The sorption behavior of technetium on pyrrhotine was studied with batch experiments and diluted sulfuric acid (less than 2.88 mol/l) was used to dissolve the technetium adsorbed on pyrrhotine. A significant sorption of technetium on pyrrhotine was observed under aerobic and anaerobic conditions, and the sorption on the mineral was supposed to be due to the reduction of TcO 4 - to insoluble TcO 2 x nH 2 O. Sorbed technetium on the mineral could be desorbed by diluted sulfuric acid. The maximum desorption ratio under aerobic conditions was much higher than that of under anaerobic conditions, meanwhile, the desorption rates under anaerobic conditions were higher than that of under aerobic conditions in the initial stage of the experiments. (author)

Reactive solute transport in streams: A surface complexation approach for trace metal sorption

Science.gov (United States)

Runkel, Robert L.; Kimball, Briant A.; McKnight, Diane M.; Bencala, Kenneth E.

1999-01-01

A model for trace metals that considers in-stream transport, metal oxide precipitation-dissolution, and pH-dependent sorption is presented. Linkage between a surface complexation submodel and the stream transport equations provides a framework for modeling sorption onto static and/or dynamic surfaces. A static surface (e.g., an iron- oxide-coated streambed) is defined as a surface with a temporally constant solid concentration. Limited contact between solutes in the water column and the static surface is considered using a pseudokinetic approach. A dynamic surface (e.g., freshly precipitated metal oxides) has a temporally variable solid concentration and is in equilibrium with the water column. Transport and deposition of solute mass sorbed to the dynamic surface is represented in the stream transport equations that include precipitate settling. The model is applied to a pH-modification experiment in an acid mine drainage stream. Dissolved copper concentrations were depressed for a 3 hour period in response to the experimentally elevated pH. After passage of the pH front, copper was desorbed, and dissolved concentrations returned to ambient levels. Copper sorption is modeled by considering sorption to aged hydrous ferric oxide (HFO) on the streambed (static surface) and freshly precipitated HFO in the water column (dynamic surface). Comparison of parameter estimates with reported values suggests that naturally formed iron oxides may be more effective in removing trace metals than synthetic oxides used in laboratory studies. The model's ability to simulate pH, metal oxide precipitation-dissolution, and pH-dependent sorption provides a means of evaluating the complex interactions between trace metal chemistry and hydrologic transport at the field scale.

Phosphorus sorption-desorption and effects of temperature, pH and salinity on phosphorus sorption in marsh soils from coastal wetlands with different flooding conditions.

Science.gov (United States)

Bai, Junhong; Ye, Xiaofei; Jia, Jia; Zhang, Guangliang; Zhao, Qingqing; Cui, Baoshan; Liu, Xinhui

2017-12-01

Wetland soils act as a sink or source of phosphorus (P) to the overlaying water due to phosphorus sorption-desorption processes. Litter information is available on sorption and desorption behaviors of phosphorus in coastal wetlands with different flooding conditions. Laboratory experiments were conducted to investigate phosphorus sorption-desorption processes, fractions of adsorbed phosphorus, and the effects of salinity, pH and temperature on phosphorus sorption on soils in tidal-flooding wetlands (TW), freshwater-flooding wetlands (FW) and seasonal-flooding wetlands (SW) in the Yellow River Delta. Our results showed that the freshly adsorbed phosphorus dominantly exists in Occluded-P and Fe/AlP and their percentages increased with increasing phosphorus adsorbed. Phosphorus sorption isotherms could be better described by the modified Langmuir model than by the modified Freundlich model. A binomial equation could be properly used to describe the effects of salinity, pH, and temperature on phosphorus sorption. Phosphorus sorption generally increased with increasing salinity, pH, and temperature at lower ranges, while decreased in excess of some threshold values. The maximum phosphorus sorption capacity (Q max ) was larger for FW soils (256 mg/kg) compared with TW (218 mg/kg) and SW soils (235 mg/kg) (p < 0.05). The percentage of phosphorus desorption (P des ) in the FW soils (7.5-63.5%) was much lower than those in TW (27.7-124.9%) and SW soils (19.2-108.5%). The initial soil organic matter, pH and the exchangeable Al, Fe and Cd contents were important factors influencing P sorption and desorption. The findings of this study indicate that freshwater restoration can contribute to controlling the eutrophication status of water bodies through increasing P sorption. Copyright © 2017 Elsevier Ltd. All rights reserved.

Qualitative comparison of duplex Stirling and absorption refrigerators in domestic applications

Energy Technology Data Exchange (ETDEWEB)

Shao, H. [Global Cooling BV, Zutphen (Netherlands)

2000-07-01

A qualitative comparison has been carried out between the duplex Stirling and the absorption refrigerator for domestic applications. The duplex Stirling has many advantages over the absorption refrigerator on efficiency, modulation, suitability, operating costs, pollution reduction. Based on the state of the art of free-piston gas-bearing and linear-motor Stirling engines and coolers, it appears technically and economically feasible to develop the duplex Stirling to compete with the absorption refrigerator for heat-driven domestic refrigeration. (orig.)

Potential benefits of saturation cycle with two-phase refrigerant injection

International Nuclear Information System (INIS)

Lee, Hoseong; Hwang, Yunho; Radermacher, Reinhard; Chun, Ho-Hwan

2013-01-01

In this paper, a saturation cycle is proposed to enhance a vapor compression cycle performance by reducing thermodynamic losses associated with single phase gas compression and isenthalpic expansion. In order to approach the saturation cycle, a two-phase refrigerant injection technique is applied to the multi-stage cycle. This multi-stage cycle with different options is modeled, and its performance is evaluated under ASHRAE standard operating conditions for air conditioning systems. Moreover, the two-phase refrigerant injection cycle is compared with the typical vapor injection cycle which is utilizing the internal heat exchanger or the flash tank. Low GWP refrigerants are applied to this two-phase refrigerant injection cycle. In terms of the COP and its improvement, R123 has a higher potential than any other refrigerants in the multi-stage cycle. Lastly, practical ideas realizing the saturation cycle are discussed such as multi-stage phase separator, phase separator with helical structure inside, and injection location of the compressor. -- Highlights: • A saturation cycle is proposed to enhance the vapor compression cycle performance. • Two-phase refrigerant injection technique is applied to the multi-stage cycle. • Modeling results of the proposed cycle show the significant performance improvement. • Low GWP refrigerants are applied and R123 shows the highest performance. • New parameters, α and ε, are used to show the potential of the saturation cycle

Suitability of Moshi Pumice for Phosphorus Sorption in Constructed ...

African Journals Online (AJOL)

The study of Moshi Pumice's phosphorus sorption behaviours and properties was carried out in laboratory scale where by 1-2 mm, 2-4 mm and 4-8 mm grains were tested using batch experiments. The results show that Moshi Pumice has high phosphorus sorption capacity. The sorption capacity for the Moshi Pumice was ...

Retail Food Refrigeration and the Phaseout of HCFC-22

Science.gov (United States)

Provides information on the HCFC phaseout that is relevant to food retailers, including alternatives to the use of HCFC-22 in retail food refrigeration, other refrigerant regulations, and resources for more information.

Numerical approach to solar ejector-compression refrigeration system

Directory of Open Access Journals (Sweden)

Zheng Hui-Fan

2016-01-01

Full Text Available A model was established for solar ejector-compression refrigeration system. The influence of generator temperature, middle-temperature, and evaporator temperature on the performance of the refrigerant system was analyzed. An optimal generator temperature is found for maximal energy efficiency ratio and minimal power consumption.

Sorption of curium by silica colloids: Effect of humic acid

International Nuclear Information System (INIS)

Kar, Aishwarya Soumitra; Kumar, Sumit; Tomar, B.S.; Manchanda, V.K.

2011-01-01

Sorption of curium by silica colloids has been studied as a function of pH and ionic strength using 244 Cm as a tracer. The sorption was found to increase with increasing pH and reach a saturation value of ∼95% at pH beyond 5.3. The effect of humic acid on the sorption of 244 Cm onto silica was studied by changing the order of addition of the metal ion and humic acid. In general, in the presence of humic acid (2 mg/L), the sorption increased at lower pH (<5) while it decreased in the pH range 6.5-8 and above pH 8, the sorption was found to increase again. As curium forms strong complex with humic acid, its presence results in the enhancement of curium sorption at lower pH. At higher pH the humic acid present in the solution competes with the surface sites for curium thus decreasing the sorption. The decrease in the Cm sorption in presence of humic acid was found to be less when humic acid was added after the addition of curium. Linear additive model qualitatively reproduced the profile of the Cm(III) sorption by silica in presence of humic acid at least in the lower pH region, however it failed to yield quantitative agreement with the experimental results. The results of the present study evidenced the incorporation of Cm into the silica matrix.

An overview of adsorptive processes in refrigeration systems

Directory of Open Access Journals (Sweden)

Wolak Eliza

2016-01-01

Full Text Available Economic reasons and quest for new solutions based on recovering the energy have provoked an increase of interest in the adsorption technology in the refrigeration industry. The confirmation can be the fact that number of published research is on rise. Adsorption appliances may turn out to be an alternative to compression-type coolers. They use ecological chemical agents instead of substances which are aggressive and harmful to the environment. For regeneration of adsorptive refrigeration systems one can use cheap energy in a form of: industrial waste heat, energy of solar radiation and cheap electric power. The paper presents principles of operation as well as advantages and disadvantages of adsorptive refrigeration systems. Basing on literature the most frequently used adsorbent – adsorbate systems – which are employed in refrigeration industry – have been characterized. A review of construction solutions of systems on both laboratory and industrial scale has been made.

Sorption of chromium(VI) and chromium(III) on aluminium hydroxide

International Nuclear Information System (INIS)

Music, S.