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Faculty of mechanical Engineering, East Bavarian Technical University (OTH Regensburg), Galgenberg Street 30, 93053 Regensburg, Germany Interests: Adsorption heat Pumps, Absorption heat Pumps, Heat and Mass transfer in Sorption Processes, REDOX Hydrogen Storage in Metal-Oxides, Energy Efficiency and Energy Management, Advanced building and energy systems
A numerical parameter sensitivity analysis of the design parameters of the recently published solar selective thermal insulation system (SATIS) has been carried out to enhance its thermal and optical properties. It turned out that the insulation properties of SATIS can be effectively improved by reducing the length of the glass closure element. Increasing the area share of the light conducting elements (LCEs) and decreasing their length-to-diameter (L/D) ratio were identified as key parameters in order to increase the solar gain. Two SATIS variants were compared with the same wall insulation without SATIS in a yearly energetic performance assessment. The SATIS variant with 10 mm length of the closure element, 44.2% area share of LCE, as well as front and rear diameters of 12 mm/9 mm shows an 11.8% lower transmission heat loss over the heating period than the wall insulation without SATIS. A new methodology was developed to enable the implementation of the computed solar gains of SATIS in 1D simulation tools. The result is a radiant heat flow map for integration as a heat source in 1D simulation models. A comparison between the 1D and 3D models of the inside wall heat fluxes showed an integral yearly agreement of 98%.
Peter Steininger; Matthias Gaderer; Belal Dawoud. Assessment of the Annual Transmission Heat Loss Reduction of a Refurbished Existing Building with an Advanced Solar Selective Thermal Insulation System. Sustainability 2021, 13, 7336 .
AMA StylePeter Steininger, Matthias Gaderer, Belal Dawoud. Assessment of the Annual Transmission Heat Loss Reduction of a Refurbished Existing Building with an Advanced Solar Selective Thermal Insulation System. Sustainability. 2021; 13 (13):7336.
Chicago/Turabian StylePeter Steininger; Matthias Gaderer; Belal Dawoud. 2021. "Assessment of the Annual Transmission Heat Loss Reduction of a Refurbished Existing Building with an Advanced Solar Selective Thermal Insulation System." Sustainability 13, no. 13: 7336.
Insulation of thermal energy storage tanks is fundamental to reduce heat losses and to achieve high energy storage efficiency. Although water tanks were extensively studied in the literature, the enhancement of the insulation quality is often overlooked. The use of vacuum insulation has the potential to significantly reduce heat losses without affecting the dimension of the storage system. This paper shows for the first time the results of the heat losses tests done for a 0.535 m3 water tank for residential building applications built with a double wall vacuum insulation. The different tests show that the rate of heat losses strictly depends on the temperature distribution inside the tank at the beginning of the experiment. Compared to a conventional water tank insulated with conventional materials, the U-value of the lateral surface was reduced by almost three times (from 1.05 W/K·m2 to 0.38 W/K·m2) using vacuum insulation. However, the bottom part, which is usually used to place the support parts and the piping, is the critical design part of those tanks acting as a thermal bridge with the ambient and enhancing heat losses.
David Vérez; Emiliano Borri; Alicia Crespo; Gabriel Zsembinszki; Belal Dawoud; Luisa Cabeza. Experimental Study of a Small-Size Vacuum Insulated Water Tank for Building Applications. Sustainability 2021, 13, 5329 .
AMA StyleDavid Vérez, Emiliano Borri, Alicia Crespo, Gabriel Zsembinszki, Belal Dawoud, Luisa Cabeza. Experimental Study of a Small-Size Vacuum Insulated Water Tank for Building Applications. Sustainability. 2021; 13 (10):5329.
Chicago/Turabian StyleDavid Vérez; Emiliano Borri; Alicia Crespo; Gabriel Zsembinszki; Belal Dawoud; Luisa Cabeza. 2021. "Experimental Study of a Small-Size Vacuum Insulated Water Tank for Building Applications." Sustainability 13, no. 10: 5329.
The present work aims at the thermodynamic analysis of different working pairs in adsorption heat transformers (AdHT) for low-temperature waste heat upgrade in industrial processes. Two different AdHT configurations have been simulated, namely with and without heat recovery between the adsorbent beds. Ten working pairs, employing different adsorbent materials and four different refrigerants, have been compared at varying working boundary conditions. The effects of heat recovery and the presence of a temperature gradient for heat transfer between sinks/sources and the AdHT components have been analyzed. The achieved results demonstrate the possibility of increasing the overall performance when internal heat recovery is implemented. They also highlight the relevant role played by the existing temperature gradient between heat transfer fluids and components, that strongly affect the real operating cycle of the AdHT and thus its expected performance. Both extremely low, i.e., 40–50 °C, and low (i.e., 80 °C) waste heat source temperatures were investigated at variable ambient temperatures, evaluating the achievable COP and specific energy. The main results demonstrate that optimal performance can be achieved when 40–50 K of temperature difference between waste heat source and ambient temperature are guaranteed. Furthermore, composite sorbents demonstrated to be the most promising adsorbent materials for this application, given their high sorption capacity compared to pure adsorbents, which is reflected in much higher achievable specific energy.
Andrea Frazzica; Valeria Palomba; Belal Dawoud. Thermodynamic Performance of Adsorption Working Pairs for Low-Temperature Waste Heat Upgrading in Industrial Applications. Applied Sciences 2021, 11, 3389 .
AMA StyleAndrea Frazzica, Valeria Palomba, Belal Dawoud. Thermodynamic Performance of Adsorption Working Pairs for Low-Temperature Waste Heat Upgrading in Industrial Applications. Applied Sciences. 2021; 11 (8):3389.
Chicago/Turabian StyleAndrea Frazzica; Valeria Palomba; Belal Dawoud. 2021. "Thermodynamic Performance of Adsorption Working Pairs for Low-Temperature Waste Heat Upgrading in Industrial Applications." Applied Sciences 11, no. 8: 3389.
A newly-developed solar active thermal insulation system (SATIS) is introduced with the main objective to accomplish a highly-dependent total solar transmittance on the irradiation angle. SATIS is also designed to obtain the maximum transmittance at a prescribed design irradiation angle and to reduce it remarkably at higher irradiation angles. A purely mineral thermal insulation plaster with micro hollow glass spheres is applied to manufacture the investigated SATIS prototype. Light-conducting elements (LCEs) have been introduced into SATIS and suitable closing elements have been applied. The SATIS prototype has been investigated both experimentally and numerically. It turned out that the contributions of conduction, radiation and convection to the effective thermal conductivity of SATIS, without the closing elements (49
Peter Steininger; Matthias Gaderer; Oliver Steffens; Belal Dawoud. Experimental and Numerical Study on the Heat Transfer Characteristics of a Newly-Developed Solar Active Thermal Insulation System. Buildings 2021, 11, 123 .
AMA StylePeter Steininger, Matthias Gaderer, Oliver Steffens, Belal Dawoud. Experimental and Numerical Study on the Heat Transfer Characteristics of a Newly-Developed Solar Active Thermal Insulation System. Buildings. 2021; 11 (3):123.
Chicago/Turabian StylePeter Steininger; Matthias Gaderer; Oliver Steffens; Belal Dawoud. 2021. "Experimental and Numerical Study on the Heat Transfer Characteristics of a Newly-Developed Solar Active Thermal Insulation System." Buildings 11, no. 3: 123.
This work aims at investigating the reduction/oxidation (redox) reaction kinetics on iron oxide pellets under different operating conditions of thermochemical hydrogen storage. In order to reduce the iron oxide pellets (90% Fe2O3, 10% stabilizing cement), hydrogen (H2) is applied in different concentrations with nitrogen (N2), as a carrier gas, at temperatures between between 700 ∘ C and 900 ∘ C , thus simulating the charging phase. The discharge phase is triggered by the flow of a mixture out of steam (H2O) and N2 at different concentrations in the same temperature range, resulting in the oxidizing of the previously reduced pellets. All investigations were carried out in a thermo-gravimetric analyzer (TGA) with a flow rate of 250 m L / m i n . To describe the obtained kinetic results, a simplified analytical model, based on the linear driving force model, was developed. The investigated iron oxide pellets showed a stable redox performance of 23.8% weight reduction/gain, which corresponds to a volumetric storage density of 2 . 8 k W h / ( L b u l k ) , also after the 29 performed redox cycles. Recalling that there is no H2 stored during the storage phase but iron, the introduced hydrogen storage technology is deemed very promising for applications in urban areas as day-night or seasonal storage for green hydrogen.
Bernd Gamisch; Matthias Gaderer; Belal Dawoud. On the Development of Thermochemical Hydrogen Storage: An Experimental Study of the Kinetics of the Redox Reactions under Different Operating Conditions. Applied Sciences 2021, 11, 1623 .
AMA StyleBernd Gamisch, Matthias Gaderer, Belal Dawoud. On the Development of Thermochemical Hydrogen Storage: An Experimental Study of the Kinetics of the Redox Reactions under Different Operating Conditions. Applied Sciences. 2021; 11 (4):1623.
Chicago/Turabian StyleBernd Gamisch; Matthias Gaderer; Belal Dawoud. 2021. "On the Development of Thermochemical Hydrogen Storage: An Experimental Study of the Kinetics of the Redox Reactions under Different Operating Conditions." Applied Sciences 11, no. 4: 1623.
This communication introduces an experimental setup for investigating the effect of solar radiation on the reduction of transmission heat losses and the steady state thermal conductance of uninsulated and insulated multi-layer wall samples. The setup consists of two adjacent climatic chambers, which share a common wall, in which the multi-layer wall samples are mounted. A solar simulator is applied within the outdoor air climatic chamber, whose radiation spectrum and radiation intensity are approximately equivalent to those of the sun. The first tests have been carried out on a wall sample with a typical structure of existing buildings from the year 1930 in Germany. In addition, a high-performance insulating plaster layer has been applied on a basic test sample (with existing building structure) to replicate and assess the refurbished scenario. Furthermore, a numerical investigation on the transient heat transfer process is carried out by using the simulation software COMSOL Multiphysics®. The experimental results of both uninsulated and insulated wall samples are validated against 1D and 3D models. As seen, the uninsulated wall, whose thermal conductance was experimentally determined to be equal to 1.79 W/(m²K), absorbs a heat flux of 208 W/m² through its external wall surface over a period of 8 hours. A fraction of 9.8 % of the absorbed heat arrives as a gain on the internal wall and reduces the transmission heat losses by 11.7 % over a period of 55 hours. On the other hand, the thermal conductivity of the insulation layer of the refurbished wall sample with micro hollow glass spheres was estimated by a parameter estimation procedure using the 3D model and the obtained experimental data. Using the estimated thermal conductivity, a thermal conductance of 0.42 W/(m²K) has been obtained for the refurbished wall sample.
Peter Steininger; Matthias Gaderer; Belal Dawoud. Experimental and numerical study on the solar gain and heat loss of typical existing and refurbished German buildings. iCRBE Procedia 2020, 75 -93.
AMA StylePeter Steininger, Matthias Gaderer, Belal Dawoud. Experimental and numerical study on the solar gain and heat loss of typical existing and refurbished German buildings. iCRBE Procedia. 2020; ():75-93.
Chicago/Turabian StylePeter Steininger; Matthias Gaderer; Belal Dawoud. 2020. "Experimental and numerical study on the solar gain and heat loss of typical existing and refurbished German buildings." iCRBE Procedia , no. : 75-93.
An innovative adsorber plate heat exchanger (APHE), which is developed for application in adsorption heat pumps, chillers and thermal energy storage systems, is introduced. A test frame has been constructed as a representative segment of the introduced APHE for applying loose grains of AQSOA-Z02. Adsorption kinetic measurements have been carried out in a volumetric large-temperature-jump setup under typical operating conditions of adsorption processes. A transient 2-D model is developed for the tested sample inside the setup. The measured temporal uptake variations with time have been fed to the model, through which a micro-pore diffusion coefficient at infinite temperature of 2 E−4 [m2s−1] and an activation energy of 42.1 [kJ mol−1] have been estimated. A 3-D model is developed to simulate the combined heat and mass transfer inside the APHE and implemented in a commercial software. Comparing the obtained results with the literature values for an extruded aluminium adsorber heat exchanger coated with a 500 μm layer of the same adsorbent, the differential water uptake obtained after 300 s of adsorption (8.2 g/100 g) implies a sound enhancement of 310%. This result proves the great potential of the introduced APHE to remarkably enhance the performance of adsorption heat transformation appliances.
Makram Mikhaeil; Matthias Gaderer; Belal Dawoud. On the development of an innovative adsorber plate heat exchanger for adsorption heat transformation processes; an experimental and numerical study. Energy 2020, 207, 118272 .
AMA StyleMakram Mikhaeil, Matthias Gaderer, Belal Dawoud. On the development of an innovative adsorber plate heat exchanger for adsorption heat transformation processes; an experimental and numerical study. Energy. 2020; 207 ():118272.
Chicago/Turabian StyleMakram Mikhaeil; Matthias Gaderer; Belal Dawoud. 2020. "On the development of an innovative adsorber plate heat exchanger for adsorption heat transformation processes; an experimental and numerical study." Energy 207, no. : 118272.
In this study, the definition of a new methodology for a preliminary evaluation of the working boundary conditions under which a seasonal thermal energy storage (STES) system operates is described. The approach starts by considering the building features as well as the reference heating system in terms of solar thermal collectors’ technology, ambient heat sinks/source, and space heating distribution systems employed. Furthermore, it is based on a deep climatic analysis of the place where the STES needs to be installed, to identify both winter and summer operating conditions. In particular, the STES energy density is evaluated considering different space heating demands covered by the STES (ranging from 10% up to 60%). The obtained results demonstrate that this approach allows for the careful estimation of the achievable STES density, which is varies significantly both with the space heating coverage guaranteed by the STES as well as with the ambient heat source/sink that is employed in the system. This confirms the need for careful preliminary analysis to avoid the overestimation of the STES material volume. The proposed approach was then applied for different climatic conditions (e.g., Germany and Sweden) and the volume of one of the most attractive composite sorbent materials reported in the literature, i.e., multi-wall carbon nanotubes (MWCNT)-LiCl, using water as the working fluid, needed for covering the variable space heating demand in a Nearly Zero Energy Building (NZEB) was calculated. In the case of Swedish buildings, it ranges from about 3.5 m3 when 10% of the space heating demand is provided by the STES, up to 11.1 m3 when 30% of the space heating demand is provided by the STES.
Andrea Frazzica; Vincenza Brancato; Belal Dawoud. Unified Methodology to Identify the Potential Application of Seasonal Sorption Storage Technology. Energies 2020, 13, 1037 .
AMA StyleAndrea Frazzica, Vincenza Brancato, Belal Dawoud. Unified Methodology to Identify the Potential Application of Seasonal Sorption Storage Technology. Energies. 2020; 13 (5):1037.
Chicago/Turabian StyleAndrea Frazzica; Vincenza Brancato; Belal Dawoud. 2020. "Unified Methodology to Identify the Potential Application of Seasonal Sorption Storage Technology." Energies 13, no. 5: 1037.
Stabilizing the effects of greenhouse gas emissions on the atmosphere is a key step towards solving the global climate change problems. Storage technologies play an essential role in compensating the discrepancy between surplus energy and peak times. Sorption processes, in particular, offer an environment friendly way for almost loss-free heat (of adsorption or absorption) and cold storage. This work is dedicated first to analytically investigate the potential of applying NaY-Water/Zeolite as a working pair for heat and cold storage upon utilizing high temperature heat. It turned out that, the mass of the adsorber heat exchanger increases the useful specific heat stored from 229 kWh/tzeolite for the ideal storage to 538 kWh/tzeolite or even higher depending on the thermal capacity of the adsorber heat exchanger (AdsHX). Contrary to that trend, COP will decrease with increasing the thermal capacity of the AdsHX. Sensible heat losses between charging and discharging phases do have a negative effect on both stored heating capacity and COP. In addition, an innovative hybrid steam power cum adsorption storage process is introduced and analytically investigated at different ambient conditions and time scenarios for on-peak and off-peak durations over the day. The introduced hybrid process seems quite promising in achieving electrical power production and efficiency enhancements during peak load durations. The extent of enhancing both performance indicators increases with increasing the ambient temperature difference between peak and off-peak times.
Kristina Geilfuß; Belal Dawoud. Analytical investigation of a zeolite-NaY-water adsorption heat and cold storage and its integration into a steam power process. Energy 2020, 195, 116977 .
AMA StyleKristina Geilfuß, Belal Dawoud. Analytical investigation of a zeolite-NaY-water adsorption heat and cold storage and its integration into a steam power process. Energy. 2020; 195 ():116977.
Chicago/Turabian StyleKristina Geilfuß; Belal Dawoud. 2020. "Analytical investigation of a zeolite-NaY-water adsorption heat and cold storage and its integration into a steam power process." Energy 195, no. : 116977.
As part of a systematic approach towards the search for alternative absorption heat pump (AHP) working pairs that could potentially provide comparable performance to conventional ones, a previous work performed a detailed theoretical cycle analysis and simulation that revealed concrete correlations between key working fluid thermophysical properties and AHP performance indicators. Following this work, targeted combinations of two organic refrigerants, 2,2,2-trifluoroethanol (TFE) and 2,2,3,3,3-pentafluoropropanol (5FP) and two organic absorbents, 1,3-dimethyl-2-imidazolidinone (DMI) and 2-pyrrolidone (PYR) were tested in a prototype 5 kW AHP, based on a highly compact plate heat exchanger design, which has been previously introduced. The purpose of this effort was to test the findings of the previous work with experimental measurements. The working pair combinations were also subjected to vapor liquid equilibrium (VLE) and viscosity measurements, in order to determine reliable activity coefficient and improve the accuracy of the simulations. The experimental performance data agree well with the COP simulations and show to be consistent with the conclusions derived from the previous theoretical work.
P. Chatzitakis; J. Safarov; F. Opferkuch; Belal Dawoud. Experimental investigation of an absorption heat pump with organic working pairs. Applied Thermal Engineering 2019, 163, 114311 .
AMA StyleP. Chatzitakis, J. Safarov, F. Opferkuch, Belal Dawoud. Experimental investigation of an absorption heat pump with organic working pairs. Applied Thermal Engineering. 2019; 163 ():114311.
Chicago/Turabian StyleP. Chatzitakis; J. Safarov; F. Opferkuch; Belal Dawoud. 2019. "Experimental investigation of an absorption heat pump with organic working pairs." Applied Thermal Engineering 163, no. : 114311.
Edoardo Proverbio; Luigi Calabrese; Angela Caprì; Lucio Bonaccorsi; Belal Dawoud; Andrea Frazzica. Susceptibility to corrosion of aluminium alloy components in ethanol adsorption chiller. Renewable Energy 2017, 110, 174 -179.
AMA StyleEdoardo Proverbio, Luigi Calabrese, Angela Caprì, Lucio Bonaccorsi, Belal Dawoud, Andrea Frazzica. Susceptibility to corrosion of aluminium alloy components in ethanol adsorption chiller. Renewable Energy. 2017; 110 ():174-179.
Chicago/Turabian StyleEdoardo Proverbio; Luigi Calabrese; Angela Caprì; Lucio Bonaccorsi; Belal Dawoud; Andrea Frazzica. 2017. "Susceptibility to corrosion of aluminium alloy components in ethanol adsorption chiller." Renewable Energy 110, no. : 174-179.
As described in Chap. 1, one of the major adsorber heat exchanger design requirements is the reduction of the ratio between the heat capacity of the adsorber heat exchanger material as well as its heat transfer medium’s holdup and the heat capacity of the applied adsorbent. This results in enhancing the coefficient of performance of the adsorption heat pump and increases the obtainable specific heating or cooling power.
Angelo Freni; Belal Dawoud; Lucio Bonaccorsi; Stefanie Chmielewski; Andrea Frazzica; Luigi Calabrese; Giovanni Restuccia. Adsorption Heat Exchangers. Tunable Low-Power Low-Noise Amplifier for Healthcare Applications 2015, 35 -53.
AMA StyleAngelo Freni, Belal Dawoud, Lucio Bonaccorsi, Stefanie Chmielewski, Andrea Frazzica, Luigi Calabrese, Giovanni Restuccia. Adsorption Heat Exchangers. Tunable Low-Power Low-Noise Amplifier for Healthcare Applications. 2015; ():35-53.
Chicago/Turabian StyleAngelo Freni; Belal Dawoud; Lucio Bonaccorsi; Stefanie Chmielewski; Andrea Frazzica; Luigi Calabrese; Giovanni Restuccia. 2015. "Adsorption Heat Exchangers." Tunable Low-Power Low-Noise Amplifier for Healthcare Applications , no. : 35-53.
Hydrothermal aging of zeolites is an irreversible change of adsorbent surface characteristics due to repeated cyclic adsorption and desorption of water resulting in, among others, reduced adsorption capacity and kinetics of adsorption.
Angelo Freni; Belal Dawoud; Lucio Bonaccorsi; Stefanie Chmielewski; Andrea Frazzica; Luigi Calabrese; Giovanni Restuccia. Hydrothermal Stability of Adsorbent Coatings. Tunable Low-Power Low-Noise Amplifier for Healthcare Applications 2015, 55 -79.
AMA StyleAngelo Freni, Belal Dawoud, Lucio Bonaccorsi, Stefanie Chmielewski, Andrea Frazzica, Luigi Calabrese, Giovanni Restuccia. Hydrothermal Stability of Adsorbent Coatings. Tunable Low-Power Low-Noise Amplifier for Healthcare Applications. 2015; ():55-79.
Chicago/Turabian StyleAngelo Freni; Belal Dawoud; Lucio Bonaccorsi; Stefanie Chmielewski; Andrea Frazzica; Luigi Calabrese; Giovanni Restuccia. 2015. "Hydrothermal Stability of Adsorbent Coatings." Tunable Low-Power Low-Noise Amplifier for Healthcare Applications , no. : 55-79.
A heat pump process is a thermodynamic process having the main target to pump heat from a heat reservoir at a low temperature (ambient heat source) to a heat sink at a higher temperature (heating net). According to the second law of thermodynamics, this target can only be realized if a driving energy is applied. Contrary to the vapor compression heat pump process, where mechanical work is applied as a driving energy to run the compressor, thermally driven heat pumps (TDHP) make use of heat at a higher temperature (driving heat source), compared to the heat sink temperature, as a driving energy.
Angelo Freni; Belal Dawoud; Lucio Bonaccorsi; Stefanie Chmielewski; Andrea Frazzica; Luigi Calabrese; Giovanni Restuccia. Basics of Adsorption Heat Pump Processes. Tunable Low-Power Low-Noise Amplifier for Healthcare Applications 2015, 1 -33.
AMA StyleAngelo Freni, Belal Dawoud, Lucio Bonaccorsi, Stefanie Chmielewski, Andrea Frazzica, Luigi Calabrese, Giovanni Restuccia. Basics of Adsorption Heat Pump Processes. Tunable Low-Power Low-Noise Amplifier for Healthcare Applications. 2015; ():1-33.
Chicago/Turabian StyleAngelo Freni; Belal Dawoud; Lucio Bonaccorsi; Stefanie Chmielewski; Andrea Frazzica; Luigi Calabrese; Giovanni Restuccia. 2015. "Basics of Adsorption Heat Pump Processes." Tunable Low-Power Low-Noise Amplifier for Healthcare Applications , no. : 1-33.
An adsorbent material consolidated in form of coating could present poor mechanical stability if a proper binder and/or an optimized binder content are not adopted in the coating formulation. Mechanical stability of the adsorbent coating may be affected by different typologies of mechanical stresses during its lifetime (vibrations, impacts, etc.). For this reason, a single mechanical test is not sufficient to prove completely the overall mechanical stability of the coated layer.
Angelo Freni; Belal Dawoud; Lucio Bonaccorsi; Stefanie Chmielewski; Andrea Frazzica; Luigi Calabrese; Giovanni Restuccia. Mechanical Stability of Adsorbent Coatings. Tunable Low-Power Low-Noise Amplifier for Healthcare Applications 2015, 81 -96.
AMA StyleAngelo Freni, Belal Dawoud, Lucio Bonaccorsi, Stefanie Chmielewski, Andrea Frazzica, Luigi Calabrese, Giovanni Restuccia. Mechanical Stability of Adsorbent Coatings. Tunable Low-Power Low-Noise Amplifier for Healthcare Applications. 2015; ():81-96.
Chicago/Turabian StyleAngelo Freni; Belal Dawoud; Lucio Bonaccorsi; Stefanie Chmielewski; Andrea Frazzica; Luigi Calabrese; Giovanni Restuccia. 2015. "Mechanical Stability of Adsorbent Coatings." Tunable Low-Power Low-Noise Amplifier for Healthcare Applications , no. : 81-96.
Belal Dawoud. On the development of an innovative gas-fired heating appliance based on a zeolite-water adsorption heat pump; system description and seasonal gas utilization efficiency. Applied Thermal Engineering 2014, 72, 323 -330.
AMA StyleBelal Dawoud. On the development of an innovative gas-fired heating appliance based on a zeolite-water adsorption heat pump; system description and seasonal gas utilization efficiency. Applied Thermal Engineering. 2014; 72 (2):323-330.
Chicago/Turabian StyleBelal Dawoud. 2014. "On the development of an innovative gas-fired heating appliance based on a zeolite-water adsorption heat pump; system description and seasonal gas utilization efficiency." Applied Thermal Engineering 72, no. 2: 323-330.
Belal Dawoud. Water vapor adsorption kinetics on small and full scale zeolite coated adsorbers; A comparison. Applied Thermal Engineering 2013, 50, 1645 -1651.
AMA StyleBelal Dawoud. Water vapor adsorption kinetics on small and full scale zeolite coated adsorbers; A comparison. Applied Thermal Engineering. 2013; 50 (2):1645-1651.
Chicago/Turabian StyleBelal Dawoud. 2013. "Water vapor adsorption kinetics on small and full scale zeolite coated adsorbers; A comparison." Applied Thermal Engineering 50, no. 2: 1645-1651.
Angelo Freni; Andrea Frazzica; Belal Dawoud; Stefanie Chmielewski; Luigi Calabrese; Lucio Bonaccorsi. Adsorbent coatings for heat pumping applications: Verification of hydrothermal and mechanical stabilities. Applied Thermal Engineering 2013, 50, 1658 -1663.
AMA StyleAngelo Freni, Andrea Frazzica, Belal Dawoud, Stefanie Chmielewski, Luigi Calabrese, Lucio Bonaccorsi. Adsorbent coatings for heat pumping applications: Verification of hydrothermal and mechanical stabilities. Applied Thermal Engineering. 2013; 50 (2):1658-1663.
Chicago/Turabian StyleAngelo Freni; Andrea Frazzica; Belal Dawoud; Stefanie Chmielewski; Luigi Calabrese; Lucio Bonaccorsi. 2013. "Adsorbent coatings for heat pumping applications: Verification of hydrothermal and mechanical stabilities." Applied Thermal Engineering 50, no. 2: 1658-1663.
International audienceThis paper presents a theoretical model for predicting the effective thermal conductivity of wetted zeolite. The model comprises the thermal conductivities of the zeolite crystal as well as of the adsorbed water. The temperature dependence of both thermal conductivities is considered. Moreover, the contribution to the effective thermal conductivity due to vapor conductance is also taken into account. The effective thermal conductivity of 4A zeolite-water is measured by transient "hot wire" method under various conditions of vapor pressure, temperature and water loading. The measurement ranges are chosen according to the operating conditions of a typical adsorption cooling cycle. The experimentally measured data are fitted to the proposed theoretical model. The maximum deviation between the experimental results and the theoretical values is estimated to be ± 5.8 %. The validated model is used to realize a zeolite 4A conductivity chart, which represents an useful tool for thermal design of adsorption machines
B. Dawoud; M. Imroz Sohel; Angelo Freni; Salvatore Vasta; Giovanni Restuccia. On the effective thermal conductivity of wetted zeolite under the working conditions of an adsorption chiller. Applied Thermal Engineering 2011, 31, 2241 -2246.
AMA StyleB. Dawoud, M. Imroz Sohel, Angelo Freni, Salvatore Vasta, Giovanni Restuccia. On the effective thermal conductivity of wetted zeolite under the working conditions of an adsorption chiller. Applied Thermal Engineering. 2011; 31 (14-15):2241-2246.
Chicago/Turabian StyleB. Dawoud; M. Imroz Sohel; Angelo Freni; Salvatore Vasta; Giovanni Restuccia. 2011. "On the effective thermal conductivity of wetted zeolite under the working conditions of an adsorption chiller." Applied Thermal Engineering 31, no. 14-15: 2241-2246.
B. Dawoud; Y.H. Zurigat; J. Bortmany. Thermodynamic assessment of power requirements and impact of different gas-turbine inlet air cooling techniques at two different locations in Oman. Applied Thermal Engineering 2005, 25, 1579 -1598.
AMA StyleB. Dawoud, Y.H. Zurigat, J. Bortmany. Thermodynamic assessment of power requirements and impact of different gas-turbine inlet air cooling techniques at two different locations in Oman. Applied Thermal Engineering. 2005; 25 (11-12):1579-1598.
Chicago/Turabian StyleB. Dawoud; Y.H. Zurigat; J. Bortmany. 2005. "Thermodynamic assessment of power requirements and impact of different gas-turbine inlet air cooling techniques at two different locations in Oman." Applied Thermal Engineering 25, no. 11-12: 1579-1598.