Models of Diffuse Solar Fraction

A modification to the f-Chart method has been developed to predict monthly and annual performance of thermosyphon solar domestic hot water systems. Stratification in the storage tank is accounted for through use of a modified collector loss coefficient. The varying flow rate throughout the day and year in a thermosyphon system is accounted for through use of a fixed monthly “equivalent average” flow rate. The “equivalent average” flow rate is that which balances the thermosyphon buoyancy driving force with the frictional losses in the flow circuit on a monthly average basis. Comparison between the annual solar fraction predited by the modified design method and TRNSYS simulations for a wide range of thermosyphon systems shows an RMS error of 2.6 percent.

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Life-cycle assessment of a 100% solar fraction thermal supply to a European apartment building using water-based sensible heat storage

Energy and Buildings ◽

10.1016/j.enbuild.2010.12.029 ◽

2011 ◽

Vol 43 (6) ◽

pp. 1231-1240 ◽

Cited By ~ 33

Author(s):

Andrew Simons ◽

Steven K. Firth

Keyword(s):

Life Cycle Assessment ◽

Life Cycle ◽

Heat Storage ◽

Sensible Heat ◽

Apartment Building ◽

Solar Fraction ◽

Water Based

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A New Design of an Integrated Solar Absorption Cooling System Driven by an Evacuated Tube Collector: A Case Study for Baghdad, Iraq

Applied Sciences ◽

10.3390/app10103622 ◽

2020 ◽

Vol 10 (10) ◽

pp. 3622 ◽

Cited By ~ 1

Author(s):

Adil Al-Falahi ◽

Falah Alobaid ◽

Bernd Epple

Keyword(s):

Thermal Performance ◽

Air Conditioning ◽

Cooling System ◽

Electrical Power ◽

Energy Performance ◽

Coefficient Of Performance ◽

Solar Absorption ◽

Air Conditioning System ◽

Solar Fraction ◽

Design Variables

The electrical power consumption of refrigeration equipment leads to a significant influence on the supply network, especially on the hottest days during the cooling season (and this is besides the conventional electricity problem in Iraq). The aim of this work is to investigate the energy performance of a solar-driven air-conditioning system utilizing absorption technology under climate in Baghdad, Iraq. The solar fraction and the thermal performance of the solar air-conditioning system were analyzed for various months in the cooling season. It was found that the system operating in August shows the best monthly average solar fraction (of 59.4%) and coefficient of performance (COP) (of 0.52) due to the high solar potential in this month. Moreover, the seasonal integrated collector efficiency was 54%, providing a seasonal solar fraction of 58%, and the COP of the absorption chiller was 0.44, which was in limit, as reported in the literature for similar systems. A detailed parametric analysis was carried out to evaluate the thermal performance of the system and analyses, and the effect of design variables on the solar fraction of the system during the cooling season.

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HIGH SOLAR FRACTION BY THERMALLY ACTIVATED COMPONENTS

10.32638/proceedings.isec2018.201834 ◽

2018 ◽

Author(s):

Thomas Ramschak ◽

Keyword(s):

Thermally Activated ◽

Solar Fraction

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Impact of a vertical geothermal heat exchanger on the solar fraction of a solar cooling system

International Journal of Refrigeration ◽

10.1016/j.ijrefrig.2017.02.007 ◽

2017 ◽

Vol 76 ◽

pp. 63-72 ◽

Cited By ~ 5

Author(s):

A. Acuña ◽

F. Lara ◽

P. Rosales ◽

J. Suastegui ◽

N. Velázquez ◽

...

Keyword(s):

Heat Exchanger ◽

Cooling System ◽

Geothermal Heat ◽

Solar Cooling ◽

Solar Fraction ◽

Geothermal Heat Exchanger ◽

Solar Cooling System

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The HIGH-COMBI project: High solar fraction heating and cooling systems with combination of innovative components and methods

Renewable and Sustainable Energy Reviews ◽

10.1016/j.rser.2013.08.019 ◽

2014 ◽

Vol 29 ◽

pp. 463-472 ◽

Cited By ~ 23

Author(s):

Vassiliki N. Drosou ◽

Panagiotis D. Tsekouras ◽

Th.I. Oikonomou ◽

Panos I. Kosmopoulos ◽

Constantine S. Karytsas

Keyword(s):

Cooling Systems ◽

Heating And Cooling ◽

Solar Fraction

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Efficiency Increase of Solar Heated Buildings by Thermal Activation of Construction Elements

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.887.659 ◽

2019 ◽

Vol 887 ◽

pp. 659-666

Author(s):

Werner Lerch ◽

Richard Heimrath ◽

Andreas Heinz ◽

Thomas Mach ◽

Christian Fink ◽

...

Keyword(s):

Heat Supply ◽

Thermal Activation ◽

Solar Thermal ◽

Building Structure ◽

Single Family ◽

Solar Thermal Energy ◽

Concrete Core ◽

Solar Fraction ◽

Heat Supply Systems ◽

Supply Systems

The Austrian project “solSPONGEhigh” [1] examines the use of thermal activation of building components in order to increase the solar fraction of the heat demand of buildings. The aim of the project is to evaluate, under which conditions a high solar fraction of a single family house (low energy building) can be achieved with solar technologies (PV and solar thermal, in this paper the focus is on solar thermal). Different heat supply systems based on solar thermal energy (basic or complex supply systems) have been defined. The systems were modeled in the simulation environment TRNSYS [2], analyzed concerning their system behavior and further developed. The investigated systems range from classical monovalent heat supply systems, systems combined with solar thermal up to complex integrated hydraulic solutions. The heating of the building via concrete core activation was compared with a conventional underfloor heating system. A detailed analysis of the dynamic system and building simulation results shows that the system efficiency can be significantly increased, if solar heat is used to charge the storage capacity of the building structure directly. A further advantage when activating the building structure (primarily concrete) is the less rapidly changing room air temperature with strongly fluctuating environmental conditions.

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