The Experts below are selected from a list of 34014 Experts worldwide ranked by ideXlab platform
Viorel Badescu - One of the best experts on this subject based on the ideXlab platform.
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modeling Solar radiation at the earth s surface recent advances
Published in 2008, 2014Co-Authors: Viorel BadescuAbstract:Solar radiation data is important for a wide range of applications, e.g. in engineering, agriculture, health sector, and in many fields of the natural sciences. A few examples showing the diversity of applications may include: architecture and building design, e.g. air conditioning and cooling Systems; Solar Heating System design and use; Solar power generation; evaporation and irrigation; calculation of water requirements for crops; monitoring plant growth and disease control; skin cancer research.
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case study for active Solar space Heating and domestic hot water preparation in a passive house
Journal of Renewable and Sustainable Energy, 2011Co-Authors: Viorel BadescuAbstract:Models for five components of an active Solar Heating System are described. The integrated model was implemented to Pirmasens Passive House (Rhineland Palatinate, Germany). Two series schemes of interconnection for the domestic hot preparation System and the space Heating System, respectively, are analyzed. Rather similar results were obtained in both cases. The active Solar System starts operation when the incoming Solar irradiance exceeds a threshold value depending on the ambient temperature and the amount of thermal energy stored in the water tank. The combined effect of passive and active Solar Systems is not able to cover the space Heating demand for the entire days of January. Most part of the collected Solar energy is used for domestic hot water preparation. The results show that the series interconnection is unfavorable for the space Heating System.
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renewable energy for passive house Heating model of the active Solar Heating System
Energy and Buildings, 2006Co-Authors: Viorel Badescu, Mihail Dan StaicoviciAbstract:The large windows on the south-oriented facade of a passive house strongly contribute to building space Heating. These windows constitute the passive Solar Heating System. This paper studies the active Heating System of a passive house, which includes the following sub-Systems: (1) Solar thermal collectors, (2) a water storage tank, (3) a secondary water circuit, (4) a domestic hot water preparation System and (5) an air ventilation and Heating System. Models for all sub-Systems are presented. The integrated model was implemented to Pirmasens Passive House (Rhineland Palatinate, Germany). The active Solar Heating System provides a smaller amount of heat than the heat provided by the passive Solar Heating System. Almost all the Solar energy collected is not used for space Heating but to domestic hot water (DHW) preparation. However, there is still a need for the classical water heater to operate all over the year. Almost all space Heating thermal load is covered by using the classical air heater that operates mainly during the nights from November to April. The Solar fraction lies between 0.180 in February and 0.679 in October, with a yearly average of 0.446. The study reveals that on a yearly basis it is more advantageous to use vertical south-oriented Solar collectors instead of roof placed collectors.
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simulation analysis for the active Solar Heating System of a passive house
Applied Thermal Engineering, 2005Co-Authors: Viorel BadescuAbstract:The active Solar Heating System consists of the following sub-Systems: (1) a Solar thermal collector area, (2) a water storage tank, (3) a secondary water circuit, (4) a domestic hot water (DHW) preparation System and (5) an air ventilation/Heating System. An improved model for the secondary water circuit is proposed and two interconnection schemes for sub-Systems (4) and (5) are analyzed. The integrated model was implemented to Pirmasens passive house (Rhineland Palatinate, Germany). Both interconnection schemes show that (almost all) the Solar energy collected is not used for space Heating but for domestic hot water preparation. The classical water heater operates all over the year and the classical air heater operates mainly during the nights from November to April. The yearly amount of heat required by the DHW preparation System is about 77% of the yearly total heat demand of the passive house and the classical water heater provides about 20% of the yearly heat required by the DHW preparation System. The Solar fraction lies between 0.247 in January and 0.930 in August, with a yearly average of 0.597.
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renewable energy for passive house Heating ii model
Energy and Buildings, 2003Co-Authors: Viorel Badescu, Benoit SicreAbstract:The evaluation of renewable energy used to increase the environmental friendliness of passive houses (PH) is the topic of this paper. A time-dependent model of passive house thermal behavior is developed. The heat-transfer through the high thermal inertia elements is analyzed by using a 1D time-dependent conduction heat-transfer equation that is solved numerically by using a standard Netlib solver (PDECHEB). Appropriate models for the conduction through the low thermal inertia elements are used, as well as a simple approach of the Solar radiation transmission through the windows. The model takes into account in a detailed fashion the internal heat sources. Also, the operation of ventilation/Heating System is described and common practice control strategies are implemented. Three renewable energy sources are considered. First, there is the passive Solar Heating due to the large window on the facade oriented south. Second, the active Solar collectors System provides thermal energy for space Heating or hot domestic water preparation. Third, a ground heat exchanger (GHE) increases the fresh air temperature during the cold season. The model was applied to the Pirmasens Passive House (Rhineland Palatinate, Germany). The passive Solar Heating System provides most part of the Heating energy during November, December, February and March while in January the ground heat exchanger is the most important renewable energy source. January and February require use of additional conventional energy sources. A clever use of the active Solar Heating System could avoid consuming classical fuels during November, December and March. The ground heat exchanger is a reliable renewable source of energy. It provides heat during all the day and its (rather small) heat flux is increasing when the weather becomes colder. The air temperature at heater exit is normally lower than 46 °C. This is a good reason for the use of renewable energy to replace the classical fuel or the wood to be burn in the heater.
Abdelhamid Farhat - One of the best experts on this subject based on the ideXlab platform.
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the effect of nocturnal shutter on insulated greenhouse using a Solar air heater with latent storage energy
Solar Energy, 2015Co-Authors: Sami Kooli, Salwa Bouadila, Mariem Lazaar, Abdelhamid FarhatAbstract:Abstract In order to reduce the energy consumption in agricultural greenhouses at night, two similar greenhouses with a nocturnal shutter are constructed and installed in the CRTEn (Research and Technologies Centre of Energy) in Tunisia. The first is equipped with a Heating System. The Solar Heating System is a Solar air heater collector with latent heat storage. At daytime, thermal Solar energy is stored, however, at night it can be restored. Moreover, the shutter is used only at night. The analysis of the thermal energy is used to examine the repartition of the absorbed, the useful, the stored and the losses of energy in the greenhouse; with or without nocturnal shutter. The balances of the various components of the greenhouse are used to study the portions of the energy recovered, absorbed, stored and lost. The experimentally obtained results show that: the nocturnal variations of temperature inside the two greenhouses exceed 2 °C between the first (with shutter) and the second one (without). Also, the nocturnal temperature inside the greenhouse equipped with Solar Heating System was maintained to 15 °C while the outside temperature decreases to 8 °C.
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energy and exergy analysis of a new Solar air heater with latent storage energy
International Journal of Hydrogen Energy, 2014Co-Authors: Salwa Bouadila, Sami Kooli, Mariem Lazaar, Safa Skouri, Abdelhamid FarhatAbstract:Abstract In this paper, we propose a new Solar air heater with a packed-bed latent storage energy System using PCM spherical capsules. At daytime, the Solar Heating System stored the thermal Solar energy as sensible and latent heat, however, at night it restored. Some parameters, such as the global Solar radiation and the mass flow rate are varied to investigate their effect on the absorbed, used, and recovered heat from the System. An optimization study using the first and second laws of thermodynamics is also carried out to obtain the energy and exergy efficiencies. The experimental study was conducted, designed, and realized in the Research and Technology Center of Energy (CRTEn) in Tunisia. The experimentally obtained results are used to analyze the performance of the System, based on temperature distribution in different parts of the collectors, absorbed, instantaneous stored and used thermal energy. The daily energy efficiency varied between 32% and 45%. While the daily exergy efficiency varied between 13% and 25%. The effect of the mass flow rate of air on the outlet temperature of the Solar air heater is examined.
Youngjin Choi - One of the best experts on this subject based on the ideXlab platform.
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thermal performance improvement method for air based Solar Heating Systems
Solar Energy, 2019Co-Authors: Youngjin ChoiAbstract:Abstract In recent years, the use of the air-based Solar Heating Systems, which heat outdoor air and use it for Heating and hot water, has increased in Japan. Air-based Solar Heating Systems do not require special equipment for Heating by direct use of air heated via convective Heating, and they can be used for the hot water supply through heat exchange when the room temperature is high. However, because Solar energy is only available during the daytime, and because of heat loss to the ground from the foundation concrete (which is a thermal storage body storing the collected heat), the load reduction effect is much less than the amount of the heat that is collected by Solar Heating. In this study, a simulation model was developed to understand the annual thermal load performance of an air-based Solar Heating System. The models of the Solar collector, hot water tank and thermal storage were verified by comparison with experimental results. In order to improve the thermal performance of conventional Systems, the Solar collector, indoor air circulation, insulation under the foundation concrete, and additional thermal storage were examined. In particular, this study examined the effect of Solar heat using water bottles that can achieve a large thermal storage effect at low cost. Simulation results show that the proposed System reduces annual Heating and hot water load by 17.9% compared to conventional Systems.
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annual Heating and hot water load reduction effect of air based Solar Heating System using thermal simulation
Energies, 2019Co-Authors: Youngjin ChoiAbstract:This study examines the effect of an air-based Solar Heating System that can be used directly for convection Heating while minimizing thermal leakage. To compare the effect of reducing the Heating and hot water load when using the System, a simulation model of the System is created, and annual load calculations are performed. The results of the simulation study show that the annual Heating load is reduced by 5.39 GJ and the hot water load is reduced by 10.32 GJ when using the air-based Solar Heating System, resulting in a 48.3% annual load reduction effect. In addition, by analyzing the thermal balance of the indoor space based on the application of the air-based Solar Heating System, the problem of the existing System is elucidated. In order to improve the performance of the System as shown in the thermal balance, it is necessary not only to improve the performance of the collector, but also to review its thermal storage, insulation, and proper control.
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System performance of a residential building using the air based Solar Heating System
Solar Energy, 2018Co-Authors: Youngjin Choi, Kozo TakaseAbstract:Abstract To apprehend the performance of a Solar Heating System, it is important to first understand the relationship between the Heating load and the System elements, such as heat collection, heat storage, and insulation, among others. Due to the fact that the performance of Solar Heating Systems fluctuates with weather conditions, in this study, measurements in three huts were collected at the same time in order to compare the influence by these factors on the System. By installing insulation on concrete, the heat absorption amount of the base concrete was reduced by 13.2% and the heat release amount was increased by 12.0%. This result shows the necessity of insulation in case of using underground space for heat storage in a Solar Heating System. Also, a possibility of water pack as thermal storage was presented for a Solar Heating System.
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An Experimental Study of the Solar Collection Performance of Liquid-Type Solar Collectors under Various Weather Conditions
MDPI AG, 2018Co-Authors: Youngjin ChoiAbstract:To design and use a Solar Heating System properly, it is very important to evaluate the performance of its Solar collector. Because the Solar collection efficiency of a Solar collector depends on the amount of Solar radiation, the conditions of the Heating medium (e.g., flow rate and inlet temperature), and the outside air temperature, it is necessary to consider the performance of the Solar collector in actual weather conditions that are likely to prevail when using the System for Heating and hot water. In the present study, test equipment was manufactured to measure the efficiency of Solar collectors. Using this equipment, the Heating characteristics of seven types of Solar collectors were measured. In addition, the amount of Solar heat collected per unit area was calculated for seven regions in Japan to compare the Solar collection performance for different weather conditions, such as the outside temperature and the amount of Solar radiation. In addition, the amount of Solar heat collected per unit area was calculated for seven regions in Japan to compare the Solar collection performance for different weather conditions, such as outside temperature and the amount of Solar radiation. The results show that the Solar collection performance is climate dependent and that it is necessary to select a suitable collector for each region through a preliminary examination of the Solar collection in the initial design stage
Mustafa Inalli - One of the best experts on this subject based on the ideXlab platform.
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Thermal and economic comparisons of Solar Heating Systems with seasonal storage used in building Heating
Renewable Energy, 2008Co-Authors: Aynur Ucar, Mustafa InalliAbstract:In this study, the thermal performances and economic savings of the three types of central Solar Heating System with seasonal storage are compared. Three types of seasonal storage were simulated: storage tank without insulation on ground, storage tank with insulation on ground, and underground storage tank without insulation. The long-term temperatures of water in the storage tank are calculated by finite element code ANSYS™. The simulation results showed that the higher Solar fraction and savings are obtained for System with storage buried into ground. Furthermore, the Solar fraction of the storage tank System with insulation is significantly higher than that of without insulation storage System. Also, the Solar fraction and savings of System with the evacuated tube collector are higher compared to other black paint flat plate collector.
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exergoeconomic analysis and optimization of a Solar assisted Heating System for residential buildings
Building and Environment, 2006Co-Authors: A Ucar, Mustafa InalliAbstract:Abstract In this study, an exergoeconomic model was developed for analysis and optimization of Solar Heating Systems with residential buildings. The optimum collector area ( A c ) and storage volume ( V ) for Solar-assisted Heating System in the Elazig, Turkey ( 38 . 7 ∘ N ) , weather conditions were obtained using MATLAB optimization toolbox. The energy and exergy losses in each of the components of a Solar Heating System with seasonal storage were also determined. The results showed that the exergy loss and total cost increased with increasing per house collector area for the trapeze and cylindirical tanks. It was found that the total cost of the cylindrical tank System was higher than that of the other trapeze tank System. The exergy loss at the cylindrical tank was 19.8%, while the exergy loss at the trapeze tank was 8.3%.
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thermal and economical analysis of a central Solar Heating System with underground seasonal storage in turkey
Renewable Energy, 2005Co-Authors: Aynur Ucar, Mustafa InalliAbstract:Thermal performance and economic feasibility of two types of central Solar Heating System with seasonal storage under four climatically different Turkey locations are investigated. The effects of storage volume and collector area on the thermal performance and cost are studied for three load sizes. The simulation model of the System consisting of flat plate Solar collectors, a heat pump, under ground storage tank and Heating load based on a finite element analysis and finite element code ANSYS™ is chosen as a convenient tool. In this study, the lowest Solar fraction value for Trabzon (41°N) and the highest Solar fraction value for Adana (37°N) are obtained. Based on the economic analysis, the payback period of System is found to be about 25–35 years for Turkey.
Salwa Bouadila - One of the best experts on this subject based on the ideXlab platform.
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the effect of nocturnal shutter on insulated greenhouse using a Solar air heater with latent storage energy
Solar Energy, 2015Co-Authors: Sami Kooli, Salwa Bouadila, Mariem Lazaar, Abdelhamid FarhatAbstract:Abstract In order to reduce the energy consumption in agricultural greenhouses at night, two similar greenhouses with a nocturnal shutter are constructed and installed in the CRTEn (Research and Technologies Centre of Energy) in Tunisia. The first is equipped with a Heating System. The Solar Heating System is a Solar air heater collector with latent heat storage. At daytime, thermal Solar energy is stored, however, at night it can be restored. Moreover, the shutter is used only at night. The analysis of the thermal energy is used to examine the repartition of the absorbed, the useful, the stored and the losses of energy in the greenhouse; with or without nocturnal shutter. The balances of the various components of the greenhouse are used to study the portions of the energy recovered, absorbed, stored and lost. The experimentally obtained results show that: the nocturnal variations of temperature inside the two greenhouses exceed 2 °C between the first (with shutter) and the second one (without). Also, the nocturnal temperature inside the greenhouse equipped with Solar Heating System was maintained to 15 °C while the outside temperature decreases to 8 °C.
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energy and exergy analysis of a new Solar air heater with latent storage energy
International Journal of Hydrogen Energy, 2014Co-Authors: Salwa Bouadila, Sami Kooli, Mariem Lazaar, Safa Skouri, Abdelhamid FarhatAbstract:Abstract In this paper, we propose a new Solar air heater with a packed-bed latent storage energy System using PCM spherical capsules. At daytime, the Solar Heating System stored the thermal Solar energy as sensible and latent heat, however, at night it restored. Some parameters, such as the global Solar radiation and the mass flow rate are varied to investigate their effect on the absorbed, used, and recovered heat from the System. An optimization study using the first and second laws of thermodynamics is also carried out to obtain the energy and exergy efficiencies. The experimental study was conducted, designed, and realized in the Research and Technology Center of Energy (CRTEn) in Tunisia. The experimentally obtained results are used to analyze the performance of the System, based on temperature distribution in different parts of the collectors, absorbed, instantaneous stored and used thermal energy. The daily energy efficiency varied between 32% and 45%. While the daily exergy efficiency varied between 13% and 25%. The effect of the mass flow rate of air on the outlet temperature of the Solar air heater is examined.