The Experts below are selected from a list of 243 Experts worldwide ranked by ideXlab platform

Masud Behnia - One of the best experts on this subject based on the ideXlab platform.

  • mantle heat exchangers for Horizontal Tank thermosyphon solar water heaters
    Solar Energy, 1999
    Co-Authors: G L Morrison, Gary Rosengarten, Masud Behnia
    Abstract:

    This paper describes the characteristics of Horizontal mantle heat exchangers for application in thermosyphon solar water heaters. A new correlation for heat transfer in Horizontal mantle heat exchangers with bottom entry and exit ports was used to predict the overall heat transfer and stratification conditions in Horizontal Tanks with mantle heat exchangers. The model of a mantle heat exchanger Tank was combined with the thermosyphon solar collector loop model in TRNSYS to develop a model of a thermosyphon solar water heater with collector loop heat exchanger. Predictions of stratification conditions in a Horizontal mantle Tank are compared with transient charging tests in a laboratory test rig. Predictions of daily energy gain in solar preheaters and in systems with in-Tank auxiliary boosters are compared with extensive outdoor measurements and the model is found to give reliable results for both daily and long-term performance analysis.

M Souliotis - One of the best experts on this subject based on the ideXlab platform.

  • Study of the distribution of the absorbed solar radiation on the performance of a CPC-type ICS water heater
    Renewable Energy, 2008
    Co-Authors: M Souliotis, Y Tripanagnostopoulos
    Abstract:

    An Integrated Collector Storage (ICS) solar water heater was designed, constructed and studied with an emphasis on its optical and thermal performance. The ICS system consists of one cylindrical Horizontal Tank properly mounted in a stationary symmetrical Compound Parabolic Concentrating (CPC) reflector trough. The main objective was the design and the construction of a low cost solar system with improved thermal performance based on the exploitation of the non-uniform distribution of the absorbed solar radiation on the cylindrical storage Tank surface. A ray-tracing model was developed to gauge the distribution of the incoming solar radiation on the absorber surface and the results were compared with those from a theoretical optical model based on the average number of reflections. The variation of the optical efficiency as function of the incident angle of the incoming solar radiation along with its dependence on the month during annual operation of ICS system is presented. The ICS device was experimentally tested outdoors during a whole year in order to correlate the observed temperature rise and stratification of the stored water with the non-uniform distribution of the absorbed solar radiation. The results show that the upper part of the Tank surface collects the larger fraction of the total absorbed solar radiation for all incident angles throughout the year. This is found to have a significant effect on the overall thermal performance of the ICS unit. In addition, the presented results can be considered important for the design and the operation of ICS systems consisting of cylindrical Tank and CPC reflectors.

  • ics solar systems with Horizontal e w and vertical n s cylindrical water storage Tank
    Renewable Energy, 2004
    Co-Authors: Y Tripanagnostopoulos, M Souliotis
    Abstract:

    Cylindrical type storage Tanks are used in most commercial ICS systems, as they resist to the pressure of water mains. ICS systems with one or two cylindrical storage Tanks combined with curved reflectors are cost effective devices and can be easily used in domestic solar applications. In this paper we compare ICS solar systems with cylindrical water storage Tank and different mountings of it in a symmetric CPC or involute reflector trough. The design, construction and experimental results from four ICS systems regarding water temperature profile, mean daily efficiency and thermal losses during night are presented and discussed. The experimental models are tested outdoors under the same weather conditions and without water drainage for a sequence of 3 days, starting the first day with cold water. During tests we have recorded solar radiation, ambient temperature, water temperature in different locations inside the storage Tank and also wind speed. The results show that during the day the ICS systems with a Horizontal Tank present a satisfactory performance in water temperature rise and heat preservation in water storage Tank during night. Regarding reflector types, the ICS models with CPC reflectors achieve higher mean daily efficiency, while models with involute reflectors present high efficiency only in low operating temperatures.

  • ICS solar systems with Horizontal (E–W) and vertical (N–S) cylindrical water storage Tank
    Renewable Energy, 2003
    Co-Authors: Y Tripanagnostopoulos, M Souliotis
    Abstract:

    Cylindrical type storage Tanks are used in most commercial ICS systems, as they resist to the pressure of water mains. ICS systems with one or two cylindrical storage Tanks combined with curved reflectors are cost effective devices and can be easily used in domestic solar applications. In this paper we compare ICS solar systems with cylindrical water storage Tank and different mountings of it in a symmetric CPC or involute reflector trough. The design, construction and experimental results from four ICS systems regarding water temperature profile, mean daily efficiency and thermal losses during night are presented and discussed. The experimental models are tested outdoors under the same weather conditions and without water drainage for a sequence of 3 days, starting the first day with cold water. During tests we have recorded solar radiation, ambient temperature, water temperature in different locations inside the storage Tank and also wind speed. The results show that during the day the ICS systems with a Horizontal Tank present a satisfactory performance in water temperature rise and heat preservation in water storage Tank during night. Regarding reflector types, the ICS models with CPC reflectors achieve higher mean daily efficiency, while models with involute reflectors present high efficiency only in low operating temperatures.

G L Morrison - One of the best experts on this subject based on the ideXlab platform.

  • mantle heat exchangers for Horizontal Tank thermosyphon solar water heaters
    Solar Energy, 1999
    Co-Authors: G L Morrison, Gary Rosengarten, Masud Behnia
    Abstract:

    This paper describes the characteristics of Horizontal mantle heat exchangers for application in thermosyphon solar water heaters. A new correlation for heat transfer in Horizontal mantle heat exchangers with bottom entry and exit ports was used to predict the overall heat transfer and stratification conditions in Horizontal Tanks with mantle heat exchangers. The model of a mantle heat exchanger Tank was combined with the thermosyphon solar collector loop model in TRNSYS to develop a model of a thermosyphon solar water heater with collector loop heat exchanger. Predictions of stratification conditions in a Horizontal mantle Tank are compared with transient charging tests in a laboratory test rig. Predictions of daily energy gain in solar preheaters and in systems with in-Tank auxiliary boosters are compared with extensive outdoor measurements and the model is found to give reliable results for both daily and long-term performance analysis.

Y Tripanagnostopoulos - One of the best experts on this subject based on the ideXlab platform.

  • Study of the distribution of the absorbed solar radiation on the performance of a CPC-type ICS water heater
    Renewable Energy, 2008
    Co-Authors: M Souliotis, Y Tripanagnostopoulos
    Abstract:

    An Integrated Collector Storage (ICS) solar water heater was designed, constructed and studied with an emphasis on its optical and thermal performance. The ICS system consists of one cylindrical Horizontal Tank properly mounted in a stationary symmetrical Compound Parabolic Concentrating (CPC) reflector trough. The main objective was the design and the construction of a low cost solar system with improved thermal performance based on the exploitation of the non-uniform distribution of the absorbed solar radiation on the cylindrical storage Tank surface. A ray-tracing model was developed to gauge the distribution of the incoming solar radiation on the absorber surface and the results were compared with those from a theoretical optical model based on the average number of reflections. The variation of the optical efficiency as function of the incident angle of the incoming solar radiation along with its dependence on the month during annual operation of ICS system is presented. The ICS device was experimentally tested outdoors during a whole year in order to correlate the observed temperature rise and stratification of the stored water with the non-uniform distribution of the absorbed solar radiation. The results show that the upper part of the Tank surface collects the larger fraction of the total absorbed solar radiation for all incident angles throughout the year. This is found to have a significant effect on the overall thermal performance of the ICS unit. In addition, the presented results can be considered important for the design and the operation of ICS systems consisting of cylindrical Tank and CPC reflectors.

  • ics solar systems with Horizontal e w and vertical n s cylindrical water storage Tank
    Renewable Energy, 2004
    Co-Authors: Y Tripanagnostopoulos, M Souliotis
    Abstract:

    Cylindrical type storage Tanks are used in most commercial ICS systems, as they resist to the pressure of water mains. ICS systems with one or two cylindrical storage Tanks combined with curved reflectors are cost effective devices and can be easily used in domestic solar applications. In this paper we compare ICS solar systems with cylindrical water storage Tank and different mountings of it in a symmetric CPC or involute reflector trough. The design, construction and experimental results from four ICS systems regarding water temperature profile, mean daily efficiency and thermal losses during night are presented and discussed. The experimental models are tested outdoors under the same weather conditions and without water drainage for a sequence of 3 days, starting the first day with cold water. During tests we have recorded solar radiation, ambient temperature, water temperature in different locations inside the storage Tank and also wind speed. The results show that during the day the ICS systems with a Horizontal Tank present a satisfactory performance in water temperature rise and heat preservation in water storage Tank during night. Regarding reflector types, the ICS models with CPC reflectors achieve higher mean daily efficiency, while models with involute reflectors present high efficiency only in low operating temperatures.

  • ICS solar systems with Horizontal (E–W) and vertical (N–S) cylindrical water storage Tank
    Renewable Energy, 2003
    Co-Authors: Y Tripanagnostopoulos, M Souliotis
    Abstract:

    Cylindrical type storage Tanks are used in most commercial ICS systems, as they resist to the pressure of water mains. ICS systems with one or two cylindrical storage Tanks combined with curved reflectors are cost effective devices and can be easily used in domestic solar applications. In this paper we compare ICS solar systems with cylindrical water storage Tank and different mountings of it in a symmetric CPC or involute reflector trough. The design, construction and experimental results from four ICS systems regarding water temperature profile, mean daily efficiency and thermal losses during night are presented and discussed. The experimental models are tested outdoors under the same weather conditions and without water drainage for a sequence of 3 days, starting the first day with cold water. During tests we have recorded solar radiation, ambient temperature, water temperature in different locations inside the storage Tank and also wind speed. The results show that during the day the ICS systems with a Horizontal Tank present a satisfactory performance in water temperature rise and heat preservation in water storage Tank during night. Regarding reflector types, the ICS models with CPC reflectors achieve higher mean daily efficiency, while models with involute reflectors present high efficiency only in low operating temperatures.

Soteris A. Kalogirou - One of the best experts on this subject based on the ideXlab platform.

  • Chapter 5 – Solar Water-Heating Systems
    Solar Energy Engineering, 2014
    Co-Authors: Soteris A. Kalogirou
    Abstract:

    Chapter 5 is on solar water-heating systems. Both passive and active systems are described. Passive systems include thermosiphon and integrated collector storage systems. The former include theoretical performance of thermosiphon solar water heaters, reverse circulation in thermosiphon systems, vertical against Horizontal Tank configurations, freeze protection, and tracking thermosiphons. Subsequently, active systems are described, which include direct circulation systems, indirect water-heating systems, air water-heating systems, heat pump systems and pool heating systems, which include the analysis of various heat losses like evaporation, radiation, convection heat losses, make-up water load, and solar radiation-heat gain. Then the characteristics and thermal analysis of heat storage systems for both water and air systems are presented. The module and array design methods are then described and include the effects of shading, thermal expansion, galvanic corrosion, array sizing, heat exchangers, pipe and duct losses, partially shaded collectors and over-temperature protection—followed by an analysis of the characteristics of differential thermostats. Finally, methods to calculate the hot water demand are given as well as a review of international standards used to evaluate the solar water heaters performance. The chapter includes also simple system models and practical considerations for the setup of solar water-heating systems, which include: pipes, supports and insulation; pumps; valves and instrumentation.

  • Solar Water-Heating Systems
    Solar Energy Engineering, 2009
    Co-Authors: Soteris A. Kalogirou
    Abstract:

    Chapter 5 is on solar water-heating systems. Both passive and active systems are described. Passive systems include thermosiphon and integrated collector storage systems. The former include theoretical performance of thermosiphon solar water heaters, reverse circulation in thermosiphon systems, vertical against Horizontal Tank configurations, freeze protection, and tracking thermosiphons. Subsequently, active systems are described, which include direct circulation systems, indirect water-heating systems, air water-heating systems, heat pump systems and pool heating systems, which include the analysis of various heat losses like evaporation, radiation, convection heat losses, make-up water load, and solar radiation-heat gain. Then the characteristics and thermal analysis of heat storage systems for both water and air systems are presented. The module and array design methods are then described and include the effects of shading, thermal expansion, galvanic corrosion, array sizing, heat exchangers, pipe and duct losses, partially shaded collectors and over-temperature protection—followed by an analysis of the characteristics of differential thermostats. Finally, methods to calculate the hot water demand are given as well as a review of international standards used to evaluate the solar water heaters performance. The chapter includes also simple system models and practical considerations for the setup of solar water-heating systems, which include: pipes, supports and insulation; pumps; valves and instrumentation.