Parametric Methodology to Optimize the Sizing of Solar Collector Fields in Series-Parallel Arrays

The analysis of solar thermal systems through numerical simulation is of great importance, since it allows predicting the performance of many configurations in any location and under different climatic conditions. Most of the simulation tools are commercial and require different degrees of training; therefore, it is important to develop simple and reliable methodologies to obtain similar results. This study presents a parametric methodology to size stationary solar collector fields, with operating temperatures up to 150 °C. The costs of the collector loop piping and the pumping power of different series–parallel arrays is considered. The proposed tool was validated with experimental data and through simulations using commercial software. The tool allows establishing series–parallel arrays and calculates the volume of the storage tank according to the thermal load. The calculation is based on the system energy balance, where the mass flow and the heat losses in the interconnections of the collectors are taken into account. The number of collectors and the optimal series–parallel array were determined. The results show deviations lower than 7% in the relative error of the temperature profiles and in the solar fraction, with respect to the results obtained by dynamic simulations.

Download Full-text

EVALUATING GLARE IN LEED CERTIFIED BUILDINGS TO INFORM CRITERIA FOR DAYLIGHTING CREDITS

Journal of Green Building ◽

10.3992/1943-4618.14.4.57 ◽

2019 ◽

Vol 14 (4) ◽

pp. 57-76

Author(s):

Robin Wilder ◽

Jaya Mukhopadhyay ◽

Tom Femrite ◽

Kevin Amende

Keyword(s):

High Performance ◽

Climatic Conditions ◽

Rating System ◽

Indoor Environmental Quality ◽

Dynamic Simulations ◽

Simulation Tools ◽

Post Occupancy Evaluation ◽

Evaluation Procedures ◽

Extensive Documentation

Extensive documentation has been developed to support the benefits of daylight for building occupants. Recently, the high performance building industry has shown a trend towards prioritizing better daylighting conditions. In response to this trend, the Leadership in Energy and Environmental Design (LEED) rating system now addresses daylighting and views as one of the criteria for compliance. However, effective daylighting has its challenges—most importantly addressing the issue of glare. This paper discusses the issue of glare and its relationship with requirements for effective daylighting within the criteria of the LEED rating system. In this study, a LEED certified building on Montana State University's campus was considered as a case study. This paper conducts an analysis by comparing the results obtained from compliance procedures for LEED with independent evaluations of glare using simulation and post occupancy evaluation surveys. This paper concludes that the ‘illuminance simulation’ option provided in the current version of LEED (LEED v4) for compliance does not adequately address the issue of glare. This paper provides recommendations to improve the LEED rating system for indoor environmental quality which include: the incorporation of glare assessment in the evaluation procedures of daylighting and views; the use of dynamic simulations that incorporate climatic conditions in the evaluation of daylighting; and evaluating glare in early stages of design by using simulation tools.

Download Full-text

Control Strategies for Multistage Solar Collector Systems

Journal of Solar Energy Engineering ◽

10.1115/1.3268262 ◽

1988 ◽

Vol 110 (3) ◽

pp. 230-232

Author(s):

C. Saltiel

Keyword(s):

Comparative Study ◽

Flow Control ◽

Numerical Simulations ◽

Control Strategy ◽

System Performance ◽

Solar Collector ◽

Control Strategies ◽

Climatic Conditions ◽

High Threshold ◽

Threshold Values

A comparative study of the yearly performance of multistage solar collector systems, (comprised of more than one collector type) with a single on/off flow control strategy for all the collectors and separate on/off controls for each collector stage, is performed. Detailed numerical simulations under a range of climatic conditions showed that there is little advantage in using individual collector controls over a single on/off control strategy when the systems operate at low collector thresholds, but differences in system performance can be quite significant at high threshold values. In addition, the choice of the single control strategy (i.e., which collector the strategy is based on) at low thresholds is not critical in terms of system performance.

Download Full-text

Performance Analyses of Temporary Membrane Structures: Energy Saving and CO2 Reduction through Dynamic Simulations of Textile Envelopes

Sustainability ◽

10.3390/su10072548 ◽

2018 ◽

Vol 10 (7) ◽

pp. 2548 ◽

Cited By ~ 1

Author(s):

Mariangela De Vita ◽

Paolo Beccarelli ◽

Eleonora Laurini ◽

Pierluigi De Berardinis

Keyword(s):

Energy Saving ◽

Environmental Sustainability ◽

Co2 Reduction ◽

Energy Performance ◽

Climatic Conditions ◽

Point Of View ◽

Thermal Mass ◽

Membrane Structures ◽

Dynamic Simulations ◽

Carbon Reduction

The aim of this research, carried out in collaboration with Maco Technology Inc., was to analyse the energy performance of temporary textile structures that are often used to host itinerant events. This paper illustrates the dynamic simulations carried on the Ducati Pavilion, designed by Maco Technology, which hosted Ducati staff during the different stages of the Superbike World Championship. Specific aspects relating to the structural/constructive system of the project were also analysed. The theme of energy saving and carbon reduction is of great importance in temporary and itinerant structures and environmental sustainability in relation to the materials used, storage, re-use, mode of transport and ability to respond efficiently to the climatic conditions of the installation sites is an important aspect. The Ducati Pavilion was modelled and analysed from an energy point of view using Design Builder software. Ways of improving performance were analysed under summer conditions. The paper focuses on the importance of optimizing the performance of textile envelopes: the methodology proposed allows visible savings in terms of energy consumption and achieves good levels of environmental comfort in temporary buildings with low thermal mass structure.

Download Full-text

Aplicaciones del Captador Solar de Placa Plana y del Captador de Tubo de Vacío en la Edificación = Applications of the Flat Plate Solar Collectors and the Vacuum Tube Solar Collectors in Building

Anales de Edificación ◽

10.20868/ade.2018.3797 ◽

2018 ◽

Vol 4 (3) ◽

pp. 25 ◽

Cited By ~ 1

Author(s):

Daniel Ferrández ◽

Carlos Moron ◽

Jorge Pablo Díaz ◽

Pablo Saiz

Keyword(s):

Flat Plate ◽

Solar Collector ◽

Energy Demand ◽

Hot Water ◽

Solar Thermal ◽

Solar Collectors ◽

Thermal Systems ◽

Vacuum Tube ◽

Solar Thermal Collectors ◽

Flat Plate Solar Collector

ResumenEl actual Código Técnico de la Edificación (CTE) pone de manifiesto la necesidad de cubrir parte de la demanda energética requerida para el abastecimiento de agua caliente sanitaria y climatización de piscinas cubiertas mediante sistemas de aprovechamiento de la energía solar térmica. En este artículo se presenta una comparativa entre las dos principales tipologías de captadores solares térmicos que existen en el mercado: el captador de placa plana y el captador de tubo de vacío, atendiendo a criterios de fracción solar, diseño e integración arquitectónica. Todo ello a fin de discernir en qué circunstancias es más favorable el uso de uno u otro sistema, comparando los resultados obtenidos mediante programas de simulación con la toma de medidas in situ.AbstractThe current Technical Building Code (CTE) highlights the need to cover part of the energy demand required for the supply of hot water and heating of indoor swimming pools using solar thermal systems. This article presents a comparison between the two main types of solar thermal collectors that exist in the market: the flat plate solar collector and the vacuum tube solar collector, according to criteria of solar fraction, design and architectural integration. All of this in order to discern in what circumstances the use of one or the other system is more favourable, comparing the results obtained through simulation programs with the taking of measurements in situ.

Download Full-text

Study of a solar air conditioning system with ejector

International Journal of Energetica ◽

10.47238/ijeca.v5i1.115 ◽

2020 ◽

Vol 5 (1) ◽

pp. 14

Author(s):

Ghodbane Mokhtar

Keyword(s):

Solar Collector ◽

Air Conditioning ◽

Human Life ◽

Electrical Energy ◽

Well Being ◽

Climatic Conditions ◽

Power Grids ◽

Air Conditioner ◽

The Face ◽

Thermal Generator

Air conditioning is one of the indispensable conditions of well-being in human life, so the face of this research to provide this basic necessity in remote areas and in desert places far from power grids. To achieve this goal, solar air conditioning has been adopted, where the compressor was replaced by an ejector, a parabolic trough solar collector and a small pump; this means that the solar air conditioner does not need a huge amount of electrical energy to operate. This paper is studding the thermodynamic cycles of this air conditioner as a function of changing the climatic conditions of Bouzaréah region in Algeria under several practical conditions of heat exchangers (Condenser, Evaporator and Generator). This study will allow the determination of the optical and thermal efficiency of the solar collector used as a solar thermal generator, refrigeration subsystem performance (COPEje) and system thermal ratio of the air conditioner, where the cooling load is estimated at 18 kW.

Download Full-text

Is It Possible to Obtain More Energy from Solar DH Field? Interpretation of Solar DH System Data

Environmental and Climate Technologies ◽

10.2478/rtuect-2021-0097 ◽

2021 ◽

Vol 25 (1) ◽

pp. 1284-1292

Author(s):

Roberts Kaķis ◽

Ilze Poļikarpova ◽

Ieva Pakere ◽

Dagnija Blumberga

Keyword(s):

Air Temperature ◽

Solar Collector ◽

Large Scale ◽

District Heating ◽

Ambient Air ◽

Energy Sector ◽

Climatic Conditions ◽

Water Tank ◽

System Productivity ◽

Ambient Air Temperature

Abstract Europe has a course to zero emissions by 2050, with a strong emphasis on energy sector. Due to climatic conditions in Latvia, district heating (DH) plays an important role in the energy sector. One of the solutions to achieve the set goals in DH is to introduce emission-free technology. Therefore, the popularity of installation of large-scale solar collector plants continues to increase in DH in Europe. The first large-scale solar collector field in the Baltic States was installed in 2019. Solar collector active area is 21 672 m2 with heat storage water tank 8000 m3. The article shows the first operation results of this system and evaluates influencing factors. The results of the analysis show that system productivity is mainly demanded by solar radiation, and the strongest correlation between these parameters were established in May. The highest correlation between ambient air temperature and produced thermal energy is reached when ambient air temperature is between 7 °C to 15 °C and production process has not been externally regulated. The temperature difference between flow and return temperatures of the heat carrier affect solar collector performance minimally and strong correlation was not observed.

Download Full-text

Performance Analysis and Design Optimization of a Mini-Channel Evacuated-Tube Solar Collector

Volume 8: Energy Systems: Analysis, Thermodynamics and Sustainability; Sustainable Products and Processes ◽

10.1115/imece2008-67858 ◽

2008 ◽

Cited By ~ 11

Author(s):

Gerardo Diaz

Keyword(s):

Solar Collector ◽

Renewable Energy Sources ◽

Geometrical Parameters ◽

Thermal Systems ◽

Round Tube ◽

Selective Coating ◽

Analysis And Design ◽

Evacuated Tube Solar Collector ◽

Performance Analysis And Design ◽

Evacuated Tube

The utilization of renewable energy sources is receiving considerable attention as a non-resource-depleting approach that reduces the emissions of pollutants and green-house gases to the atmosphere. Solar thermal systems have the capability to provide heat in a sustainable way for a variety of applications due to the relatively large range of temperatures that different collector configurations can attain. Most evacuated-tube solar collectors currently found on the market consist of a u-shaped round tube, concentric round tubes in counter flow regime, or a heat-pipe. The external surface in these designs is welded to a thin absorber fin that is covered with a selective coating. This paper analyzes the performance of an evacuated-tube solar collector that contains a U-shaped mini-channel tube. Comparisons of performance with respect to standard u-shaped round-tube solar collector are made. The design of a mini-channel based solar collector without absorber fin is also analyzed and its performance optimized with respect to its geometrical parameters.

Download Full-text

Improvement of energy performances of existing buildings by application of solar thermal systems

Spatium ◽

10.2298/spat0920019k ◽

2009 ◽

pp. 19-22 ◽

Cited By ~ 1

Author(s):

Aleksandra Krstic-Furundzic ◽

Vesna Kosoric

Keyword(s):

Energy Savings ◽

Residential Buildings ◽

Climatic Conditions ◽

Building Envelope ◽

Solar Thermal ◽

Existing Buildings ◽

Thermal Systems ◽

Climate Conditions ◽

Solar Thermal Collectors ◽

Reduction Of Co2

Improvement of energy performances of the existing buildings in the suburban settlement Konjarnik in Belgrade, by the application of solar thermal systems is the topic presented in this paper. Hypothetical models of building improvements are created to allow the benefits of applying solar thermal collectors to residential buildings in Belgrade climate conditions to be estimated. This case study presents different design variants of solar thermal collectors integrated into a multifamily building envelope. The following aspects of solar thermal systems integration are analyzed in the paper: energy, architectural, ecological and economic. The results show that in Belgrade climatic conditions significant energy savings and reduction of CO2 emissions can be obtained with the application of solar thermal collectors.

Download Full-text

System Performance of an Indirect Collector Storage Preheater in Series With a Conventional Electric Resistance Water Heater

Solar Energy ◽

10.1115/isec2005-76200 ◽

2005 ◽

Cited By ~ 1

Author(s):

A. M. Boies ◽

K. O. Homan

Keyword(s):

Thermal Performance ◽

System Performance ◽

Low Cost ◽

Electric Resistance ◽

Water Heating ◽

Water Heater ◽

Domestic Water ◽

Solar Fraction ◽

Storage Volume ◽

In Series

Solar integral collector storage (ICS) devices are a potentially low cost means of displacing a portion of the energy required for domestic water heating. However, since ICS systems are rarely used as a stand-alone system and are more typically utilized as a preheater for conventional water heaters, it is imperative to analyze the overall water heating system in order to determine the advantage of any improvements in the thermal performance of the ICS component. In particular, this paper analyzes the performance of a solar ICS heater, in divided and undivided storage configurations, in series with a conventional electric resistance water heater (ERWH) for a range of ICS storage volumes, heat exchanger NTU, initial ICS temperature, and ERWH storage volumes. The undivided storage configuration corresponds to the typical UPICS system whereas the divided storage configuration corresponds to a recently proposed concept for improving the thermal performance of the ICS device. The results show that the ICS preheater does provide significant increases in solar fraction when adequately sized. Although comparison of the divided to undivided storage concept, with the same total ICS storage volume, shows only modest gains of 5–10% in solar fraction, the ICS storage volume necessary to attain the same solar fraction is much less for the divided storage concept. The smaller required storage volume would, in turn, enable faster charging times and potentially higher initial temperatures thereby leading to even further improvements in overall system performance.

Download Full-text