The Experts below are selected from a list of 312 Experts worldwide ranked by ideXlab platform
Hans Mullersteinhagen - One of the best experts on this subject based on the ideXlab platform.
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german central Solar Heating plants with seasonal heat storage
Solar Energy, 2010Co-Authors: D Bauer, Hans Mullersteinhagen, Roman Marx, J Nusbickerlux, F Ochs, W HeidemannAbstract:Central Solar Heating plants contribute to the reduction of CO2-emissions and global warming. The combination of central Solar Heating plants with seasonal heat storage enables high Solar fractions of 50% and more. Several pilot central Solar Heating plants with seasonal heat storage (CSHPSS) built in Germany since 1996 have proven the appropriate operation of these systems and confirmed the high Solar fractions. Four different types of seasonal thermal energy stores have been developed, tested and monitored under realistic operation conditions: Hot-water thermal energy store (e.g. in Friedrichshafen), gravel-water thermal energy store (e.g. in Steinfurt–Borghorst), borehole thermal energy store (in Neckarsulm) and aquifer thermal energy store (in Rostock). In this paper, measured heat balances of several German CSHPSS are presented. The different types of thermal energy stores and the affiliated central Solar Heating plants and district Heating systems are described. Their operational characteristics are compared using measured data gained from an extensive monitoring program. Thus long-term operational experiences such as the influence of net return temperatures are shown.
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central Solar Heating plants with seasonal storage in germany
Solar Energy, 2004Co-Authors: T Schmidt, D Mangold, Hans MullersteinhagenAbstract:Abstract In the house building sector, central Solar Heating plants presently offer the most cost-favourable application of all possibilities of Solar-thermal systems. By the integration of seasonal heat storage, more than 50% of the annual Heating demand for space Heating and domestic hot water can be supplied by Solar energy. Since 1995, eight central Solar Heating plants with seasonal heat storage have been built in Germany within the governmental R&D-programme ‘Solarthermie-2000’. This report describes the technology of central Solar Heating plants and gives advice about planning and costs. The pilot and demonstration plants for seasonal heat storage already built in Germany are described in detail to give an idea about possible system design and applications of central Solar Heating plants.
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.
Gang Pei - One of the best experts on this subject based on the ideXlab platform.
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numerical study and experimental validation of a combined diurnal Solar Heating and nocturnal radiative cooling collector
Applied Thermal Engineering, 2018Co-Authors: Bin Zhao, Gang PeiAbstract:Abstract Neither Solar collectors nor nocturnal radiative cooling units could work all day. A novel combined diurnal Solar Heating and nocturnal radiative cooling (SH-RC) collector was proposed and investigated in this study. The collector can obtain heat at daytime and gather cooling energy at nighttime, therefore offering multi-functionality and enhancing its time utilization ratio. A spatial distributed parameter mathematic model that considers the spectral radiant distribution was established to evaluate the performance of the collector. Besides, the precipitable water vapor amount was introduced to predict the spectral emissivity of atmosphere. Experiments were conducted to validate results obtained from the numerical simulation. The root-mean-square deviations between the experimental and simulation results are only 4.59% for thermal efficiency and 4.90% for cooling power. Based on the validated models, the thermal performance of the collector was investigated under different insulation thicknesses, wind velocities, ambient and inlet temperatures, water flow rates, precipitable water vapor amounts and Solar irradiance. Annual performances of four Chinese cities were also conducted. The annual heat gains of the SH-RC collector in Beijing, Hefei, Fuzhou and Urumqi are 3328.76, 2423.53, 2543.31 and 3313.46 MJ/m2, respectively. The annual net radiative cooling gains of the collector in the four cities are 862.44, 831.54, 741.63 and 775.34 MJ/m2, respectively.
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parametric analysis and annual performance evaluation of an air based integrated Solar Heating and radiative cooling collector
Energy, 2018Co-Authors: Bin Zhao, Gang PeiAbstract:Abstract Given the disadvantaged seasonal adaptability of Solar air heaters and radiative air coolers, this study proposed an air-based integrated Solar Heating (SH) and radiative cooling (RC) collector (SH–RC collector). Such dual-function collector is capable of obtaining heat in SH mode and gaining cooling energy in RC mode. Accordingly, an air-based SH–RC collector can offer hot air during cold and harvest seasons and provide cool air during hot seasons. A spectrally selective plate termed as TPET collecting plate was trial-manufactured, serving as the panel of the air-based SH–RC collector. Also, this study developed a mathematical model and investigated the SH and RC performances of the proposed collector on a fine summer day. As the results suggest, the average thermal efficiency of the collector in SH mode reaches 45.88%, and the average cooling power of the collector is 36.61 W/m 2 . Parametric studies on the effect of various ambient temperatures, inlet air temperatures, air flow rates, relative humidity values, and wind velocities on the SH and RC performances of the collector have been conducted. In addition, the monthly energy gains of the air-based SH–RC collector were calculated. The annual heat and cooling gains of the SH–RC collector reached 2328.45 and 980.43 MJ, respectively.
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field test and preliminary analysis of a combined diurnal Solar Heating and nocturnal radiative cooling system
Applied Energy, 2016Co-Authors: Gang Pei, Qiliang Wang, Yunyun WangAbstract:Abstract A type of composite surface was manufactured for trial to achieve integrated Solar Heating and radiative cooling functions. The spectral properties of the composite surface present a relatively clear selectivity in the spectra of Solar Heating and radiation cooling wavelengths. A combined system for both Solar Heating and radiative cooling (named SH-RC system) based on the composite surface was mounted together with a traditional flat-plate Solar Heating system. Comparative experiments were carried out to investigate their thermal performances both at daytime and nighttime. Results showed that the composite surface has a relatively evident spectral selectivity. In diurnal collector testing mode, the thermal efficiency of the SH-RC collector was 62.7% at zero-reduced temperature, which was about 86.4% of that of the traditional flat-plate Solar Heating collector. In nocturnal collector testing mode, the SH-RC collector had net radiative cooling powers of 50.3 W/m2 on a clear night and 23.4 W/m2 on an overcast night; by contrast, the traditional flat-plate Solar Heating collector exhibited very little radiative cooling capacity. In diurnal system testing mode, the daily average thermal efficiency of the SH-RC system and the traditional flat-plate Solar Heating system at zero-reduced temperature was 38.6% and 48.4%, respectively. Based on experimental results, the SH-RC system showed a considerable performance for both diurnal Solar Heating and nocturnal radiative cooling.
Yunyun Wang - One of the best experts on this subject based on the ideXlab platform.
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field test and preliminary analysis of a combined diurnal Solar Heating and nocturnal radiative cooling system
Applied Energy, 2016Co-Authors: Gang Pei, Qiliang Wang, Yunyun WangAbstract:Abstract A type of composite surface was manufactured for trial to achieve integrated Solar Heating and radiative cooling functions. The spectral properties of the composite surface present a relatively clear selectivity in the spectra of Solar Heating and radiation cooling wavelengths. A combined system for both Solar Heating and radiative cooling (named SH-RC system) based on the composite surface was mounted together with a traditional flat-plate Solar Heating system. Comparative experiments were carried out to investigate their thermal performances both at daytime and nighttime. Results showed that the composite surface has a relatively evident spectral selectivity. In diurnal collector testing mode, the thermal efficiency of the SH-RC collector was 62.7% at zero-reduced temperature, which was about 86.4% of that of the traditional flat-plate Solar Heating collector. In nocturnal collector testing mode, the SH-RC collector had net radiative cooling powers of 50.3 W/m2 on a clear night and 23.4 W/m2 on an overcast night; by contrast, the traditional flat-plate Solar Heating collector exhibited very little radiative cooling capacity. In diurnal system testing mode, the daily average thermal efficiency of the SH-RC system and the traditional flat-plate Solar Heating system at zero-reduced temperature was 38.6% and 48.4%, respectively. Based on experimental results, the SH-RC system showed a considerable performance for both diurnal Solar Heating and nocturnal radiative cooling.
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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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.
