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G N Tiwari - One of the best experts on this subject based on the ideXlab platform.

  • calculation of total Solar Fraction for different orientation of greenhouse using 3d shadow analysis in auto cad
    Energy and Buildings, 2012
    Co-Authors: Ravi Gupta, G N Tiwari, Anil Kumar, Yadvika Gupta
    Abstract:

    Abstract The distribution of the incoming transmitted Solar radiation (radiation which enters inside the greenhouse through canopy cover) on the floor and on the inner walls of the greenhouse has been studied to evaluated total Solar Fraction/Solar Fraction. Total Solar Fraction/Solar Fraction is required to write an energy balance equation for each component of a greenhouse. The evaluation has been done for different orientations of an even span greenhouse located at New Delhi (28.5° latitude), India. The effect of length and the width of the greenhouse on the total Solar Fraction have also been evaluated. Three-dimensional shadow analysis in Auto-CAD has been used for the study. A typical clear day of winter and summer has been considered and it was observed that total Solar Fraction was higher in winter as compared to summer. Numerically, there is not much effect of orientation on total Solar Fraction of a day for a greenhouse. However, an orientation of 45° clock-wise (for greenhouse initially at East–West orientation) resulted in lowest radiation loss during winter and maximum loss during summer. Total Solar Fraction plays an important role for smaller greenhouses. The methodology can be used for designing a greenhouse of any shape and size for any location.

  • thermal modeling based on Solar Fraction and experimental study of the annual and seasonal performance of a single slope passive Solar still the effect of water depths
    Desalination, 2007
    Co-Authors: Anil Kr Tiwari, G N Tiwari
    Abstract:

    Abstract This paper reports on the annual as well as seasonal performance analysis for different water depths in a single slope passive Solar still of cover inclination of 30°. The experiments were conducted through out the year from June 2004 to May 2005 on six clear days of every month for 24 hours a day, for six different water depths. This experimental set up has been installed at the IIT Delhi, New Delhi, India the latitude of which is 28.35′N. The lower depth has been found giving the highest annual yield. Increasing the water depth decreases the yield of the still up to depths of about 0.1 m but at greater depths than this the yield becomes almost constant. The developed thermal model has validated the hourly yield for various water depths in summer and winter. The various modes of internal energy transfer within still have been evaluated and compared relatively for different depths and seasons. The dominance of evaporative Fraction within 32–37°C has been noticed depending on the water depth under consideration. The concept of Solar Fraction and hourly values of Solar azimuth and altitude angles has been used in thermal modeling to predict different parameters. The experimental value of yield of different water depth has been compared with the theoretical values obtained by thermal modeling and found in agreement. The effect of various parameters like ambient air velocities, basin absorptivity have been found and compared for the different water depths in still. The above results reported in detail within this paper have been found in accordance to the results obtained by earlier researchers.

  • Modeling and Experimental Validation of Total Solar Fraction for Even Span Greenhouses by Shadow Area Concept
    Agricultural Engineering International: The CIGR Journal, 2007
    Co-Authors: S. A Mansoor, G N Tiwari
    Abstract:

    In this paper, an attempt has been made to evaluate total Solar Fraction (which is the ratio of the area of the shadow outside greenhouse to the total shadow area of the greenhouse) experimentally and theoretically for an even span greenhouse at New Delhi (28.58°N) by measuring the shadow length and then evaluating the shadow area. Greenhouse floor dimensions are 6m × 4m, wall height 2m and ridge height 3m. Experimental shadow data were obtained for a typical day of each month from 9 am to 3 pm for one year. It has also been validated theoretically (relation between geometrical shape of greenhouse, sun rays, and sun earth angles). There is fair agreement between experimental and theoretical results in both cases. Solar Fraction obtained from shadow area is higher during winter than summer period. The value of Solar Fraction is higher at any particular time of the day, than that obtained earlier by Auto-CAD because the present study includes beam and diffuse radiations together, and it is the sum of Solar Fraction from all walls of greenhouse. The hourly variation of greenhouse room air temperature has also been predicted for typical day of winter and summer month respectively.

  • THERMAL MODELING OF PASSIVE AND ACTIVE Solar STILLS FOR DIFFERENT DEPTHS OF WATER BY USING THE CONCEPT OF Solar Fraction
    Solar Energy, 2006
    Co-Authors: Rajesh Tripathi, G N Tiwari
    Abstract:

    Abstract This communication presents the thermal analysis of passive and active Solar distillation system by using the concept of Solar Fraction inside the Solar still with the help of AUTOCAD 2000 for given Solar azimuth and altitude angle and latitude, longitude of the place. Experiments have been conducted for 24 h (9 am to 8 am) for New Delhi climatic conditions (latitude 28°35′N, longitude 77°12′E) during the months of November and December for different water depths in the basin (0.05, 0.1 and 0.15 m) for passive as well as active Solar distillation system. Analytical expressions for water and glass cover temperatures and yield have been derived in terms of design and climatic parameters. It is observed that (i) the Solar Fraction plays a very important role at lower values of Solar altitude angle; (ii) the internal convective heat transfer coefficient decreases with the increase of water depth in the basin due to decrease in water temperature; (iii) there is a fair agreement between the experimental observation and theoretical prediction during daytime as compared to that during the night.

  • Performance evaluation of a Solar still by using the concept of Solar Fractionation
    Desalination, 2004
    Co-Authors: Rajesh Tripathi, G N Tiwari
    Abstract:

    Abstract In this communication an attempt has been made to find out distribution of Solar radiation, using the concept of Solar Fraction inside a conventional (single slope) Solar still by using AUTOCAD 2000 for a given Solar azimuth and altitude angle and latitude, longitude of the place. Further the experimental validation of the model developed earlier has been carried out for design and climatic parameters. Numerical computations have been carried out for New Delhi climatic conditions (latitude 28°35′ N, longitude 77°12′E). It has been observed that for given parameters, Solar Fraction can play a very important role at a lower value of the Solar altitude angle.

Mustafa Inalli - One of the best experts on this subject based on the ideXlab platform.

  • Thermal and economic comparisons of Solar heating systems with seasonal storage used in building heating
    Renewable Energy, 2008
    Co-Authors: Aynur Ucar, Mustafa Inalli
    Abstract:

    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.

  • Thermal and economic comparisons of Solar heating systems with seasonal storage used in building heating
    Renewable Energy, 2008
    Co-Authors: Ali Uçar, Mustafa Inalli
    Abstract:

    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. ?? 2008 Elsevier Ltd. All rights reserved.

  • thermal and economical analysis of a central Solar heating system with underground seasonal storage in turkey
    Renewable Energy, 2005
    Co-Authors: Aynur Ucar, Mustafa Inalli
    Abstract:

    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.

Adnan Shariah - One of the best experts on this subject based on the ideXlab platform.

  • Effect of thermal conductivity of absorber plate on the performance of a Solar water heater
    Applied Thermal Engineering, 1999
    Co-Authors: Adnan Shariah, Akram Rousan, Kh.k. Rousan, A. A. Ahmad
    Abstract:

    Abstract The effect of thermal conductivity of the absorber plate of a Solar collector on the performance of a thermosyphon Solar water heater is studied by the use of the transient simulation system (TRNSYS) computer program. The system is assumed to supply hot water at 55° and 80°C representing both domestic and industrial uses respectively. Hot water of volumes 50, 125, and 250 l is consumed daily according to the Rand distribution profile. The results have shows that the annual Solar Fraction of the system and the collector`s characteristic factors (namely, fin efficiency factor, collector efficiency factor, and heat removal factor) have a very strong dependence on the thermal conductivity for its low values, and weak dependence is observed beyond a thermal conductivity value of 50 W/m °C for the Solar Fraction and beyond a value of 100 W/m °C for the characteristic factors. It is also observed that the annual Solar Fraction is improved by about 4%–7% and the characteristic factors are improved by about 12%–19% when a steel absorber plate is replaced by an aluminium one, whereas, the Solar Fraction and the characteristic factors are increased only about 1% and 3%, respectively, when a copper plate is used instead of an aluminium one.

  • Optimal design for a thermosyphon Solar water heater
    Renewable Energy, 1997
    Co-Authors: Adnan Shariah, Bassam Shalabi
    Abstract:

    Through the use of TRNSYS, a transient simulation program, optimization of design parameters for a thermosyphon Solar water heater was studied for two regions in Jordan represented by two cities, namely Amman and Aqaba. The optimum value of a parameter is defined as the value which maximizes the annual Solar Fraction of a system. This paper includes a good deal of information concerning sizing of common components of thermosyphon Solar water heaters operated under certain condition (load volume, distribution profile and temperature) using weather data of Jordan. The results indicate that the Solar Fraction of the system can be improved by 10–25% when a proper choice is used for each studied parameter. It is also shown that the Solar Fraction of a system installed in Aqaba (hot climate) is less sensitive to some parameters than the Solar Fraction of a similar installed in Amman (mild climate).

  • The optimization of tank-volume-to-collector-area ratio for a thermosyphon Solar water heater
    Renewable Energy, 1996
    Co-Authors: Adnan Shariah
    Abstract:

    Through the use of the TRNSYS simulation program, the performance of a domestic Solar water heating system operating with natural circulation (thermosyphon) and a daily hot water load has been analysed. The effect of tank height on the annual Solar Fraction of the system has been investigated for different hot water load temperatures and storage tank volumes. Optimum values (values which maximize the annual Solar Fraction of the system) for storage tank height and volume are calculated for operating temperatures ranging from 50 to 80°C. The response of the system to the ratio of the storage tank volume to the collector area is investigated. The dependence of the Solar Fraction on tank height was observed to be more notable in the case of large tank volumes and high load temperatures. The results indicate the existence of an optimum value for the tank volume at a given tank height and a high load temperature. At lower temperatures, the Solar Fraction rises rapidly with tank volume to a nearly constant level. An optimum value of the storage-tank-volume-to-collector-area ratio was also observed at high load temperatures.

  • effect of hot water load temperature on the performance of a thermosyphon Solar water heater with auxiliary electric heater
    Energy Conversion and Management, 1995
    Co-Authors: Adnan Shariah, Ayse Ecevit
    Abstract:

    A thermosyphon Solar water heating system with an in-tank auxiliary electric heater has been simulated for different hot water load temperatures using the TRNSYS simulation program. The results of the simulation show that the annual efficiency and Solar Fraction are functions of the hot water load temperatures. The effect of load temperature on the Solar Fraction is found to be very large when the daily load volume (the volume of hot water delivered to load) to collector area ratio is large. The influence of storage tank volume to collector area ratio on the efficiency of the collector is observed only when this ratio is less than or equal to 40 1 m2 for all collector areas and load temperatures studied. Generally, the annual average storage tank temperature depends on the load temperature and had lower values for high load temperatures. The response of the system performance to the area of the collector is found to be very large when the system operates with a Solar Fraction below 70%.

D. R. Wilson - One of the best experts on this subject based on the ideXlab platform.

  • simulation studies of the position of the auxiliary heater in thermosyphon Solar water heating systems
    Renewable Energy, 1997
    Co-Authors: I M Michaelides, D. R. Wilson
    Abstract:

    This paper investigates the effect of the physical location of the auxiliary source of energy in thermosyphon Solar water heaters and shows that the performance of the system can be optimised with respect to the geometry of the system components. The investigation has been based on a domestic thermosyphon Solar water heating system, which was simulated using the TRNSYS programme. The annual Solar Fraction of the system, at the weather and socioeconomic conditions of Cyprus, is, at best, approximately 77% with an in-tank auxiliary heater configuration and 86% with an external auxiliary heater. It is demonstrated that the arrangement with the external auxiliary unit has a higher collector efficiency and results in a higher annual Solar Fraction. In the case of in-tank auxiliary, the system performance increases with the height of the auxiliary position from the bottom of the storage tank; with the auxiliary at the bottom of the storage tank the annual Solar Fraction is approximately 59%, compared to 77% when the auxiliary is located at the top of the tank. The system performance also depends on the height of the collector return from the bottom of the tank.

John Kokko - One of the best experts on this subject based on the ideXlab platform.

  • The Performance of a High Solar Fraction Seasonal Storage District Heating System – Five Years of Operation☆
    Energy Procedia, 2012
    Co-Authors: Bruce Sibbitt, Doug Mcclenahan, Reda Djebbar, Jeff Thornton, Bill Wong, Jarrett Carriere, John Kokko
    Abstract:

    The Drake Landing Solar Community in Okotoks, Alberta, Canada utilizes a Solar thermal system with borehole seasonal storage to supply space heating to 52 detached energy-efficient homes through a district heating network. Systems of similar size and configuration have been constructed in Europe, however, this is the first system of this type designed to supply more than 90% of the space heating with Solar energy and the first operating in such a cold climate (5200 degree C-days). Solar heat captured in 2293 m2 of flat-plate collectors, mounted on the roofs of detached garages, is stored in soil underground and later when needed for space heating, is extracted and distributed through a district system to each home in the subdivision. Independent Solar domestic hot water systems installed on every house are designed to supply more than 50% of the water heating load. Annual greenhouse gas emission reductions from energy efficiency improvements and Solar energy supply exceed 5 tonnes per house. The seasonal storage utilizes approximately 34,000 m3 of earth and a grid of 144 boreholes with single u-tube heat exchangers. The system is configured to maintain the centre of the field at the highest temperature to maximize heating capacity and the outer edges at the lowest temperature to minimize losses. A short -term thermal storage consisting of 240 m3 of water is used to interconnect the collection, distribution and seasonal heat storage subsystems. The system has undergone detailed monitoring since it was brought into service in July 2007 to characterize its performance and to improve the TRNSYS model employed in its design. A Solar Fraction of 97% in its fifth year of operation, convincingly confirms the design target, a Solar Fraction of more than 90% in year five, has been met. This paper describes the system and its operation, presents 5 years of measured performance and compares those results against the TRNSYS predicted performance for the same period.

  • the performance of a high Solar Fraction seasonal storage district heating system five years of operation
    Energy Procedia, 2012
    Co-Authors: Bruce Sibbitt, Doug Mcclenahan, Reda Djebbar, Jeff Thornton, Bill Wong, Jarrett Carriere, John Kokko
    Abstract:

    The Drake Landing Solar Community in Okotoks, Alberta, Canada utilizes a Solar thermal system with borehole seasonal storage to supply space heating to 52 detached energy-efficient homes through a district heating network. Systems of similar size and configuration have been constructed in Europe, however, this is the first system of this type designed to supply more than 90% of the space heating with Solar energy and the first operating in such a cold climate (5200 degree C-days). Solar heat captured in 2293 m2 of flat-plate collectors, mounted on the roofs of detached garages, is stored in soil underground and later when needed for space heating, is extracted and distributed through a district system to each home in the subdivision. Independent Solar domestic hot water systems installed on every house are designed to supply more than 50% of the water heating load. Annual greenhouse gas emission reductions from energy efficiency improvements and Solar energy supply exceed 5 tonnes per house. The seasonal storage utilizes approximately 34,000 m3 of earth and a grid of 144 boreholes with single u-tube heat exchangers. The system is configured to maintain the centre of the field at the highest temperature to maximize heating capacity and the outer edges at the lowest temperature to minimize losses. A short -term thermal storage consisting of 240 m3 of water is used to interconnect the collection, distribution and seasonal heat storage subsystems. The system has undergone detailed monitoring since it was brought into service in July 2007 to characterize its performance and to improve the TRNSYS model employed in its design. A Solar Fraction of 97% in its fifth year of operation, convincingly confirms the design target, a Solar Fraction of more than 90% in year five, has been met. This paper describes the system and its operation, presents 5 years of measured performance and compares those results against the TRNSYS predicted performance for the same period.