scholarly journals Adsorptive Solar Refrigerators Based on Composite Adsorbents ’Silica Gel – Sodium Sulphate’

2019 ◽  
Vol 29 (3) ◽  
pp. 200-208 ◽  
Author(s):  
Elena A. Belyanovskaya ◽  
Grigoriy N. Pustovoy ◽  
Kostyntyn M. Sukhyy ◽  
Yana O. Sergiyenko ◽  
Oleksandr O. Yeromin ◽  
...  
Keyword(s):  
Silica Gel ◽  
Process Parameters ◽  
Energy Performance ◽  
Sodium Sulphate ◽  
Coefficient Of Performance ◽  
Regeneration Process ◽  
Sulphate Content ◽  
Composite Adsorbents ◽  
The Difference

Abstract The operation processes of adsorptive solar refrigerators based on composite adsorbents ‘silica gel - sodium sulphate’ were studied. The correlation between the adsorbent composition and the coefficient of the energy performance of the device was stated. As a consequence of the decreasing of adsorbent mass, the coefficient of performance is increased when sodium sulphate content in the composite increased. Effect of the regeneration process parameters on the composite on the coefficient of performance of the adsorptive refrigenerator was stated. The growth of the coefficient of performance is shown to result from decreasing the difference between adsorbent temperature and regeneration temperature from 85 to 55°C. The maximum values of the coefficient of performance of studied solar adsorptive refrigenerator about of 1.14 are stated for composites containing about 20 wt. % silica gel and 80 wt. % sodium sulphate.

Construction and Operating Parameters of Adsorptive Chillers

2021 ◽  
pp. 251-289
Keyword(s):  
Silica Gel ◽  
Density Ratio ◽  
Energy Performance ◽  
Sodium Sulphate ◽  
Efficiency Factor ◽  
Radiant Flux ◽  
Coefficient Of Performance ◽  
Solar Collectors ◽  
Optical Efficiency ◽  
And Performance

The chapter is devoted to the design and performance of adsorptive chillers. Basic types of design and operating principle of adsorptive chillers were analyzed. Advantages and disadvantages performance of one-, two-, three-, and four-bed solar power adsorptive chillers are compared. Performance of adsorptive refrigerators based on composite adsorbents was studied. The correlation between the adsorbent composition and the coefficient of energy performance of the adsorptive chiler was revealed. An optimal composition of adsorbent 'silica gel – sodium sulphate' is stated to be of 20% silica gel and 80% sodium sulphate. The maximal values of the coefficient of performance of cycle of studied solar adsorptive chiller about of 1.14 are stated for composites containing about 20 wt. % silica gel and 80 wt% sodium sulphate. As a consequence of decreasing of adsorbent mass, the coefficient of performance is shown to increase when sodium sulphate content in the composite increased. Regeneration process parameters of the composite were shown to strongly affect on the coefficient of performance of the adsorptive chiller. The growth of the coefficient of performance is stated to result from decreasing the difference between adsorbent temperature and regeneration temperature from 85 to 55°C. The basic factors affecting the net coefficient of energy performance of the adsorptive solar refrigerator were stated daily solar radiant flux alongside with composition of the adsorbent and difference between adsorbent temperature and temperature regeneration. Net coefficients of performance of solar adsorptive refrigerator based on composite ‘silica gel – sodium sulphate' were stated to change from 0.25 to 0.34 during operating period. Utilization of the adsorption heat is suggested to warm the heat carrier which applied to heat adsorbent during regeneration. The ways to improve the design and performance of adsorptive solar chillers are suggested. The first one involves the introduction of solar collectors made of cellular polycarbonate plastics in the design of adsorptive solar chiller. Instantaneous efficiency coefficient were calculated as special thermal performance-solar radiant flux surface density ratio, optical efficiency factor is determined as special thermal performance-solar radiant flux surface density ratio at the equal temperatures of heat transfer medium and environment, reduced heat loss factor being calculated as the product of solar collector efficiency factor and net heat loss coefficient. The environmental test of developed collectors PSK-AV2-3, PSK-AV1-2, PSK-AV2-1, PSK-VS1-2, PSK-VS2-2, PSK-VS2-3, PSK-ST10-PW were conducted. The correlation of their results with laboratory tests when the thermohydraulic stand applied is shown. Relative accuracy of laboratory and environment tests was shown to be not exceeding 5 – 7%. The optical efficiency factor and the coefficient of thermal losses of polymeric solar collectors were determined. On the basis of the dependencies of the efficiency of the solar collectors vs. the reduced temperature, optimal designs of the polymeric solar collectors for the adsorption chilling solar systems are determined to be depended on the temperature of the regeneration temperature of the sorbents. As the temperatures of the regeneration of composite adsorbent ranged from 50ºС to 60ºС, appliance of the collectors PSK-AV2-1, PSK-CT10-PW occur to be expedient, and PSK-AB2-3, PSK-VS2-3, PSK-AB1-2, PSK-VS2-2, and PSK-VS1-2 are revealed to be more efficient when regeneration temperatures increased over 80 ºС. Thermotechnical characteristics of designed polymeric solar collectors are shown to surpass conventional metal and vacuum collectors. The perspectives of polymeric solar collectors in the design of adsorptive chilling solar plants were shown. Another way to improve the performance of adsorptive solar chillers concerns with equipping it with a photosensitive element and an electric drive, which will allow changing the angle of slope of the adsorber to the horizon depending on the intensity of the solar radiation. The chapter can be useful for design the efficient adsorptive chilling plants.

scholarly journals PERFORMANCE EVALUATION OF ADSORPTIVE REFRIGERATORS BASED ON COMPOSITE ADSORBENTS "SILICA GEL – SODIUM SULPHATE" AND "SILICA GEL – SODIUM ACETATE"

2019 ◽  
Vol 2 (83) ◽  
Author(s):  
Олена Анатоліївна Бєляновська ◽  
Григорій Миколайович Pustovoy ◽  
Михайло Порфирович Сухий ◽  
Костянтин Михайлович Сухий ◽  
Роман Дмитрович Литовченко
Keyword(s):  
Surface Area ◽  
Silica Gel ◽  
Solar Collector ◽  
Sodium Acetate ◽  
Sodium Sulphate ◽  
Coefficient Of Performance ◽  
Operational Parameters ◽  
Composite Adsorbents ◽  
Operational Characteristics ◽  
Cold Box

Abstract. Performance of adsorptive refrigerators based on composite adsorbents  ‘silica gel – sodium sulphate’ and ‘silica gel – sodium acetate’ was evaluated. The main characteristics of adsorbents which affect the structural parameters of the adsorptive chilling device are revealed. The method of determining operational characteristics of adsorptive refrigerator has been developed. The main factors affecting the mass of adsorbent are confirmed to be maximal adsorption and the amount of heat required to be taken from the cold box during the day. The advantages of ‘salt in the porous silica gel matrix’ composites are exhibited as compared with conventional silica gels and zeolites. Operational parameters of adsorptive refrigerators based on the composites ‘silica gel – sodium sulphate’ and 'silica gel – sodium acetate' are compared. The calculation procedure to determine the design and operational characteristics is suggested. Proposed procedure includes the calculation of the amount of heat required to be taken from the cold box during the day, water mass, mass of the adsorbent, heat required for regeneration of the adsorbent, computing the surface area of the solar collector, heat supplied by solar collector and net coefficient of performance. The efficiency of operating processes of adsorptive refrigerators based on composites 'silica gel - sodium sulphate' and 'silica gel-sodium acetate' was compared. The correlation between adsorbent composition and design and operational parameters was stated. The surface area of solar collector is stated to be of 9.46 – 9.93. The highest net coefficients of performance of 0.358 and 0.368 are revealed for devices based on composites containing, wt. %: silica gel – 20 and salt (sodium sulphate or sodium acetate) – 80. The influence of meteorological conditions on the net coefficient of performance of the adsorptive refrigerator has been confirmed. The higher efficiency of adsorptive chilling devices based on composites 'silica gel - sodium acetate' is explained by lower values of regeneration temperature, which leads to the decreasing the heat of regeneration. The results of the research can be used for the development of adsorptive chilling devices for domestic needs and warehouse premises.

Design and Performance of Adsorptive Heat Pumps

2021 ◽  
pp. 223-250
Keyword(s):  
Heat Pump ◽  
Silica Gel ◽  
Heat Supply ◽  
Sodium Acetate ◽  
Energy Performance ◽  
Heat Pumps ◽  
Sodium Sulphate ◽  
Heat Supply Systems ◽  
And Performance ◽  
Supply Systems

The chapter is devoted to design and performance of adsorptive heat pumps. In the first sub-division, state-of-the-art of the adsorptive heat pumping is analyzed. It involves analysing operating principle of adsorptive heat pumps, comparing of the properties of adsorbents used, bed specifications, and operating conditions. Original construction of the adsorptive heat pump is designed by authors for independent heat supply systems or hot water supply of buildings and other structures for various purposes. The composites ‘silica gel – sodium sulphate' or ‘silica gel – sodium acetate' were used as adsorbents. Discharging was performed in a daytime, when heat pump supplied heating system with water warmed to 45 – 35°C. The regeneration mode proceeded at night from 0.00 to 8.00 a.m. Efficiency of suggested adsorptive heat pump is estimated by two methods: as ratio of adsorption heat to sum of desorption heat and external heat supplied to sorbent during its heating up to regeneration temperature (coefficient of performance of cycle) and as ratio of heat of adsorption to heat supplied by solar collector (net coefficient of performance). Suggested heat pump coefficients of energy performance of cycle are stated to be 2.084 when composite ‘silica gel – sodium sulphate' used and 2.021 when ‘silica gel – sodium acetate' used. Seasonal dependence of net coefficient energy performance for suggested adsorptive heat pump based on composites ‘silica gel – sodium sulphate' and ‘silica gel – sodium acetate' is revealed. Correlation of coefficients of energy performance of adsorptive heat pump and composite sorbents properties (sorption capacity and regeneration temperature) is stated. Insignificant decreasing of coefficients of energy performance when ‘silica gel – sodium acetate' used is explained by lower sorptive capacity as compared to ‘silica gel – sodium sulphate'. Suggested heat pump application perspectives are shown for heat supply systems to result from traditional energy sources independence and environmental advantages. Adsorptive heat pumps development challenges, major limitations for commercialization of adsorptive heat pumping, and requirements to ongoing innovations are analysed. The present chapter can be useful for energy efficient decentralized heat supply systems based on adsorptive heat pump unit.

Structure and Properties of Composite Adsorbents Salt Inside Porous Matrix

2021 ◽  
pp. 43-87
Keyword(s):  
Silica Gel ◽  
Sol Gel ◽  
Salt Content ◽  
Porous Matrix ◽  
Sodium Sulphate ◽  
Crystalline Hydrate ◽  
Host Matrix ◽  
Gel Method ◽  
Composite Adsorbents ◽  
Silicon Oxygen

The chapter is devoted to structure and properties of composite adsorbents ‘salt inside porous matrix'. Characteristics of adsorbents ‘salt inside porous matrix', such as ‘zeolite – crystalline hydrate', ‘vermiculite – crystalline hydrate', ‘silica gel – crystalline hydrate' were analysed. Main advantages of composite adsorbents are shown to be higher adsorptive capacity and lower regeneration temperature as compared with host matrix. Adsorptive capacities of composite materials are shown to be significantly enhanced by introduction of salts in host matrix such as zeolite, vermiculite, or silica gel. Water uptake by composite adsorbent is shown to be increased by rising the salt content in it. The drawback of most of existing impregnation technologies is shown to be impossibility of obtaining composite with salt content more than 40 – 60% along with complexity. Sol gel method is shown to be an alternative for conventional impregnation methods. Properties of adsorbents ‘silica gel – sodium sulphate' synthesized according to sol gel method developed by authors were considered. The composite ‘silica gel – sodium sulphate' composition and structure were studied by IR-spectroscopy and wide-angle x-ray scattering. Adsorptive properties of crystalline Na2SO4 when allocated in silicon oxygen matrix are shown to result from dispersion up to nanoscale. Adsorptive capacities and heat of adsorption of composites ‘silica gel – sodium sulphate' and ‘silica gel – sodium acetate' surpass almost by 30% the value calculated from the linear superposition of the sorption capacities of the sorbent and massive salt. Their adsorption properties are shown to be not a linear combination of properties of silica gel and salt. The formation of a unique structure promoting an increase in the rate of reaction between crystalline hydrates and water vapor in the developed pores of the silicon-oxygen matrix is confirmed. It leads to increasing the heat of adsorption and the heat energy storage density. Strong difference of water sorption kinetic curves of composite ‘silica gel – sodium sulphate' and massive sodium sulphate is revealed. The correlation of their composition, structure, water adsorption kinetic, and operating characteristic as heat storage material is stated.

Design of Adsorptive Heat Storage Devices

2021 ◽  
pp. 89-123
Keyword(s):  
Silica Gel ◽  
Heat Supply ◽  
Sodium Acetate ◽  
Heat Storage ◽  
Sodium Sulphate ◽  
Silica Gels ◽  
Storage Devices ◽  
Composite Adsorbents ◽  
Supply Systems

The chapter is devoted to prospects of application of adsorptive heat storage devices, principles of operating the adsorptive heat storage systems, design of adsorptive storage devices and main factors determining the design of adsorptive heat storage unit. Perspectives of application of adsorptive heat storage devices in heat supply systems were analyzed. Basic principles of operating of heat storage devices were considered. Adsorptive heat storage units operating in close and open modes were compared. Constructions of adsorptive heat storage units operating in open and close mode were described. An efficient algorithm for calculating the volume of the adsorptive thermal energy storage device for a decentralised heat supply system of a private house is suggested by authors. The following procedure of computation is proposed to involve: calculation of thermal load for heating including the determination of thermal losses through external fences, thermal losses due to infiltration and internal heat dissipation, the evaluation of maximal adsorption, adsorption heat, and determination of adsorbent mass and adsorbent volume. The maximal adsorption value is suggested to be calculated by the characteristics of the adsorbent, that is, its maximal adsorption or in the absence of data for a composite adsorbent, as a linear superposition for a mechanical mixture. The adsorbent mass is suggested to calculate as a ratio of a thermal load for heating and heat of adsorption. The adsorbent volume is calculated as ratio of mass and density of adsorbent. An evaluative calculation of the heat load for a private house was carried out with the proposed algorithm. Mass and volumes of conventional silica gels were compared with composite adsorbents ‘silica gel – sodium sulphate' and ‘silica gel – sodium acetate' obtained by sol gel method developed by authors. Mass and volume of silica gels occur to surpass the suggested composite at least by 1.5 – 5 times. This is shown to result from higher maximal adsorption and heat of adsorption of suggested composite adsorbents. The optimal composition of the composite adsorbents ‘silica gel – sodium sulphate' and ‘silica gel – sodium acetate' was determined according to the minimal volume of the layer of heat storage material. Both the lowest volume values and the highest efficiency of a composite adsorbents with a mass ratio of silica gel and Na2SO4 or CH3COONa 20: 80 are explained by the maximum value of adsorption heat. Suggested composite adsorbent ‘silica gel – sodium sulphate' and ‘silica gel – sodium acetate' are shown to be promising for heat supply systems.

scholarly journals ADSORPTIVE CHILLING DEVICES BASED ON COMPOSITE ADSORBENTS «SILICA GEL – SODIUM SULPHATE»

2018 ◽  
Vol 0 (39) ◽  
pp. 94-98
Author(s):  
Elena Anatolyevna Belyanovskay ◽  
Grigoriy Nikolayevich Pustovoy ◽  
Kostyantyn Mikchaylovich Sukhyy ◽  
Elena Viktorovna Kolomiyets ◽  
Mikhailo Porfyrovich Sukhyy
Keyword(s):  
Silica Gel ◽  
Sodium Sulphate ◽  
Composite Adsorbents

Sodium salt scaling in black liquor evaporators and the effects of the addition of tall oil brine

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Erik Karlsson ◽  
Anders Åkesjö
Keyword(s):  
Sodium Carbonate ◽  
Sodium Salt ◽  
Black Liquor ◽  
Sodium Sulphate ◽  
Salt Solutions ◽  
Tall Oil ◽  
Sulphate Content ◽  
Inhibition Effect ◽  
Salt Scaling ◽  
Primary Nucleation

AbstractSodium salt scaling, i. e. the formation of doubles salts comprised of sodium, carbonate and sulphate on the heat transfer surfaces, is a common problem that occurs during black liquor evaporation. In this study, experimental results are presented that provide new insights into the formation and composition of such scales and how they are influenced by the addition of tall oil brine. It was found that increased content of sodium carbonate and sodium sulphate in the black liquor increased scaling, while the ratio between carbonate and sulphate had a lesser influence than reported in other studies. Black liquor created loose clay-like scales comprised of aggregated crystals and black liquor, whereas salt solutions created hard mineral-like scales. The scales formed by both the black liquor and the salt solution showed a tendency to fall off during formation after primary nucleation. It was also found that both tall oil soap and alkalized tall oil brine could inhibit the formation of scales. The inhibition effect is stronger if adding the soap or brine just before scaling starts, but also depends on the amount added, the sodium carbonate and sodium sulphate content in the liquor as well as other factors.

scholarly journals Water Extraction from Air: A Proposal for a New Indicator to Compare Air Water Generators Efficiency

Energies ◽  
2021 ◽  
Vol 14 (1) ◽  
pp. 224
Author(s):  
Lucia Cattani ◽  
Anna Magrini ◽  
Paolo Cattani
Keyword(s):  
Energy Efficiency ◽  
Comprehensive Evaluation ◽  
Specific Energy Consumption ◽  
Energy Performance ◽  
Water Extraction ◽  
Coefficient Of Performance ◽  
Efficiency Evaluation ◽  
Evaluation Approach ◽  
Cycle Systems ◽  
Definition Of

Water extraction from air, based on reverse cycle systems, is becoming a technology more and more diffused and various models of air to water generators (AWG) are now available, all claiming the best efficiency. To date, there is not a standard indicator stating energy efficiency for AWGs, neither in the literature nor in technical practice. The only evaluation parameter, that can be found is a sort of specific energy consumption (SEC) without any clear indications about the involved calculation terms, definition of hypotheses, or environmental conditions. The current work is a first proposal of an indicator to standardise the AWG efficiency evaluation. The indicator is called WET (Water Energy Transformation); it states water production as a useful effect of an AWG machine and calculates its energy performance with an approach similar to COP (Coefficient of Performance) and EER (Energy Efficiency Ratio) evaluation. The indicator is meant to be a normalised tool that permits comparing different AWG machines, but it is also the first part of a wider study, currently under development that is oriented to obtain a global index formulation that combines WET itself, EER and COP, and it is intended for a comprehensive evaluation of all the useful effects of a reverse cycle in integrated machines, in compliance with the current efficiency evaluation approach. The current paper presents the WET equation, with a discussion about involved terms, a set of normalised calculation conditions and some application examples, including a comparison with SEC.

scholarly journals Performance and style in the work of Olgyay and Olgyay

2014 ◽  
Vol 18 (2) ◽  
pp. 167-176 ◽  
Author(s):  
David Leatherbarrow ◽  
Richard Wesley
Keyword(s):  
Graphical Representation ◽  
Building Design ◽  
The United States ◽  
Energy Performance ◽  
Control Device ◽  
Simulation Software ◽  
Open Architecture ◽  
Form Generation ◽  
The Difference ◽  
Building Energy Analysis

The sun control device has to be on the outside of the building, an element of the facade, an element of architecture. And because this device is so important a part of our open architecture, it may develop into as characteristic a form as the Doric column.Victor Olgyay (1910–1970), a Hungarian architect who came to the United States in 1947 with his twin brother and collaborator, Aladár (1910–1963), is best known today as the author of Design with Climate: Bioclimatic Approach to Architectural Regionalism (1963), an important book often referenced in the environmental building design field [1]. As leaders in research in bioclimatic architecture from the early 1950s to the late 1960s, the Olgyay brothers could be considered the ‘fathers’ of contemporary environmental building design. Their research and publications laid the foundation for much of the building simulation software in use today. Other than the difference between working on graph paper and using computer-generated graphics, there is little difference between Autodesk's Ecotect Analysis (simulation and building energy analysis software) and the Olgyays' techniques for the analysis of environmental factors and graphical representation of climate. The manner in which the Olgyays established connections between building design and the science of climate laid the foundation for the development of environmental simulation, one of contemporary architecture's leading methods of form generation. Victor Olgyay's teaching, however, represents another kind of thinking, a broader concern for architecture, beyond energy performance. ‘The primary task of architecture,’ Olgyay announced to his students, ‘is to act in man's favour; to interpose itself between man and his natural surroundings in order to remove the environmental load from his shoulders.

scholarly journals Barotropic Regeneration of Upper-Level Synoptic Disturbances in Different Configurations of the Zonal Weather Regime

2008 ◽  
Vol 65 (10) ◽  
pp. 3159-3178 ◽  
Author(s):  
Gwendal Rivière
Keyword(s):  
Large Scale ◽  
Deformation Field ◽  
Regeneration Process ◽  
Barotropic Model ◽  
Weather Regime ◽  
The North ◽  
The Difference ◽  
Upper Level ◽  
Composite Maps ◽  
Large Scale Flow

Barotropic dynamics of upper-tropospheric midlatitude disturbances evolving in different configurations of the zonal weather regime (i.e., in different zonal-like large-scale flows) were studied using observational analyses and barotropic model experiments. The contraction stage of upper-level disturbances that follows their elongation stage leads to an increase of eddy kinetic energy that is called the barotropic regeneration process in this text. This barotropic mechanism is studied through notions of barotropic critical regions (BtCRs) and effective deformation that have been introduced in a previous paper. The effective deformation field is equal to the difference between the square of the large-scale deformation magnitude and the square of the large-scale vorticity. Regions where the effective deformation is positive correspond to regions where the large-scale flow tends to strongly stretch synoptic disturbances. A BtCR is an area separating two large-scale regions of positive effective deformation, one located upstream and on the south side of the jet and the other downstream and on the north side. Such a region presents a discontinuity in the orientation of the dilatation axes and is a potential area where the barotropic regeneration process may occur. Winter days presenting a zonal weather regime in the 40-yr ECMWF Re-Analysis dataset are decomposed, via a partitioning algorithm, into different configurations of the effective deformation field at 300 hPa. A six-cluster partition is obtained. Composite maps of the barotropic generation rate for each cluster exhibit a succession of negative and positive values on both sides of the BtCRs. It confirms statistically that the barotropic regeneration mechanism occurs preferentially about BtCRs. Numerical experiments using a forced barotropic model on the sphere are performed. Each experiment consists of adding a synoptic-scale perturbation to one of the zonal-like jet configurations found in observations, which is kept fixed with time. The combined effects of the effective deformation and nonlinearities are shown to be crucial to reproduce the barotropic regeneration process about BtCRs.

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