Active Solar Research Articles

Experimental study on effect of an active solar heating soil heat storage system on the thermal environment in Gobi solar greenhouses

Experimental study on effect of an active solar heating soil heat storage system on the thermal environment in Gobi solar greenhouses

Thermal Energy Resource Potentials of the Kara-Bogaz-Gol Gulf as a “Solar Pond”

Introduction. The use of environmentally-friendly engineering systems including solar energy technologies makes it possible to reduce energy costs and therefore to lower production costs and anthropogenic stress on the environment.Aim of the Study. The authors used innovative techniques to assess the thermal resource potential of solar radiation, to analyze the salt deposits of the Kara-Bogaz-Gol Gulf as thermal accumulators for the development, introduction and use of solar thermal technologies and to justify the technical and economic feasibility of their use in engineering systems in the Kara-Bogaz-Gol Gulf (Caspian region).Meterials and Methods. The study design is based on systematic theoretical calculations of the gross, technical, economic and ecological potentials of solar radiation taking into account environmental conditions. For calculating there were used the methods of mathematical modeling of heat and mass transfer processes in active solar energy systems when converting solar energy into thermal energy in the salty reservoir of the Kara-Bogaz-Gol Gulf as a “solar pond”.Results. There have been assessed the solar energy characteristics for the introduction of various engineering storage systems and technologies. There have been determined the results of energy storage on the reservoir salt surface during the day: in winter – 1 009.0 W/m2 per day, in summer – 1 574.7 W/m2 per day. It has been proven that the potential of solar energy conversion into thermal energy varies from 40 to 70% depending on the season. Aaccording to theoretical calculations, the solar pond efficiency in winter is 11.4% and in summer – 14.6%. In summer, there was measured the average temperature on the salt surface of the reservoir bottom, it ranges from 55.04 to 79.8 ºC, in winter from 20.0 to 25.6 ºC.Discussion and Conclusion. The results obtained can be used for strengthening energy security, developing energy systems and producing autonomous thermal power devices based on solar energy that will reduce the energy consumption of fossil fuels and improve the environmental situation in the region. The materials of the article can be used in preparing design estimates and feasibility study for developing various solar energy systems and technologies in the Caspian region.

Energy analysis of standalone hybrid active solar room heating system

AbstractIn winter, offices use heat pumps, electric heaters, and blowers to stay warm, but these use traditional energy that is not sustainable or eco‐friendly. To meet the requirements of thermal comfort, an environmentally friendly and self‐sustainable system was developed at Madhav Institute of Technology and Science in Gwalior, India. This system includes a heat exchanger, a flat plate collector, an evacuated tube collector, and a pump. Two versions of the system were tested: one with a heat exchanger and an evacuated tube collector (HEWETC) and another with a heat exchanger and a flat plate collector (HEWFPC). The results showed that the HEWETC system is better at heating the room and has higher efficiency compared to the HEWFPC system. The HEWFPC system is 12% efficient, while the HEWETC system is 21% efficient. The room stayed at a constant temperature of 26.3°C all day. The HEWETC and HEWFPC systems provided 0.46 and 0.55 MJ of heat to the room, respectively. During the heating season, the solar heat collected was 8030.38 kWh, and electricity used was 5229.7 kWh. The HEWETC system proved to be effective and suitable for heating the building.

Analysis of the Use of Energy Storage in the Form of Concrete Slabs as a Method for Sustainable Energy Management in a System with Active Thermal Insulation and Solar Collectors

One effective approach to reducing the energy required for heating buildings is the use of active thermal insulation (ATI). This method involves delivering low-temperature heat to the exterior walls through a network of pipes carrying water. For ATI to be cost-effective, the energy supply must be affordable and is typically derived from geothermal or solar sources. Solar energy, in particular, requires thermal energy storage (TES) to manage the gap between summer and the heating season. A building that integrates various renewable energy systems and heating/cooling technologies should be managed efficiently and sustainably. The proper integration of these systems with smart management strategies can significantly lower a building’s carbon footprint and operational costs. This study analyzes the use of concrete slabs as a method for sustainable energy management in a system incorporating active thermal insulation and solar collectors. Using ambient temperature and solar radiation data specific to Cracow, Poland, the simulations evaluate the feasibility of employing a concrete slab positioned beneath the building as a thermal storage tank. The results reveal some drawbacks of using concrete slabs, including high temperatures that negatively affect system efficiency. Increased temperatures lead to higher heat losses, and during summer, inadequate insulation can cause additional heat leakage into the building. The findings suggest that water may be a more effective alternative for thermal energy storage.

Numerical simulations of exocomet transits: Insights from β Pic and KIC 3542116

In recent years, the topic of existence and exploration of exocomets has been gaining increasing attention. The asymmetrical decrease in the star’s brightness due to the passage of a comet-like object in front of the star was successfully predicted. It was subsequently confirmed on the basis of the light curves of stars observed by Kepler and TESS orbital telescopes. Since then, there have been successful attempts to fit the asymmetrical dips observed in the stars’ light curves utilizing a simple 1D model of an exponentially decaying optically thin dust tail. In this work, we propose fitting the photometric profiles of some known exocomet transits based on a Monte Carlo approach to build up the distribution of dust particles in a cometary tail. As the exocomet prototypes, we used the physical properties of certain Solar System comets belonging to the different dynamical groups and moving at heliocentric distances of 0.6 au, 1.0 au, 5.0 au, and 5.5 au. We obtained a good agreement between the observed and modeled transit light curves. We also show that the physical characteristics of dust particles, such as the particle size range, the power index of dust size distribution, the particle terminal velocity, and distance to the host star affect the shape of the transit light curve, while the dust productivity of the comet nucleus and the impact parameter influence its depth and duration. The estimated dust production rates of the transiting exocomets are at the level of the most active Solar System comets.

Energy Consumption at Accommodation Buildings: A Case Study of a Boutique Hotel-Abdera

Global environmental problems such as decreasing biodiversity, natural disasters, climate change, and energy consumption are among the main concerns of the countries. Approximately 50% of the energy consumed worldwide is spent on architectural construction, use, and operation. The increase in energy consumption in buildings especially has taken the reduction of carbon footprint and the importance of energy efficiency to the fore. Physical environment, climate, orientation, envelope, and material properties are among the different factors in determining energy consumption in buildings. The share of tourism activities in total emissions is estimated to be 5%. However, it is also stated that tourism buildings have a share of 21 % of C02 emissions. This work aimed to research the energy consumption of a boutique hotel in Abdera, Greece. ArchiCAD, Graphisoft, and EcoDesigner software were used in the analysis of findings, and suggestions were put forward. Energy consumption and environmental effects were investigated when active solar systems (Solar Thermal Panel /STP (30 m2), Photovoltaic Panel/PV (30 m2)) were added to the roof surface (total 60 m2 Panel) of the building. The analysis showed that the addition of active solar systems by 30% could reduce emissions. In Greece, which is located in a very favorable region in terms of geographical features, it is very important to use solar potential with integrated systems in buildings to provide energy needs.

Solar PV tracking system using arithmetic optimization with dual axis and sensor

Presently, PV system is considered the best renewable energy source for electricity production. In order to maximize energy output in photovoltaic systems, a system for tracking the sun's position and adjusting panel positions was created. Despite the fact that several models for tracking solar radiation have been suggested to improve energy production, it faces challenges in continuous tracking and power consumption. This paper proposes a novel sensor-based solar tracking system with numerical optimization to increase photovoltaic systems' energy output. The initial model was for a two-axis tracking system based on sensors. Solar panel and sun positions are detected by this system using ultraviolet and microelectromechanical sun sensors. To improve tracking movements and photovoltaic energy production, we recommend using solar sensors to construct a novel two-axis solar tracking device. This technology benefits from increased solar radiation and solar energy harvesting capabilities. The main disadvantage of dual-axis active solar tracking systems is that the drive mechanism frequently uses up the output power of the solar panels. As a result, the net power gain of the solar panel is less than its maximum. Further, a control system was developed with proportional integral derivative (PID) controller and arithmetic optimization (AO) to adjust the panel position relative to suns movement. The AO technique tunes the PID controller gains until it reaches its desired level to enhance the production of power. With the use of sensors, the tracking system can use mathematical optimization algorithms and the sun's position to minimize power consumption while still maintaining optimal solar panel positioning. The developed model was designed in the MATLAB software and the outcomes are analyzed. The paper also presents an energy analysis of the system, which evaluates the energy input, output and overall system efficiency. We recommend using solar sensors to create a unique dual-axis solar tracking system. This technology benefits from increased solar radiation and solar energy harvesting capabilities.

The Active Asteroids Citizen Science Program: Overview and First Results

We present the Citizen Science program Active Asteroids and describe discoveries stemming from our ongoing project. Our NASA Partner program is hosted on the Zooniverse online platform and launched on 2021 August 31, with the goal of engaging the community in the search for active asteroids—asteroids with comet-like tails or comae. We also set out to identify other unusual active solar system objects, such as active Centaurs, active quasi-Hilda asteroids (QHAs), and Jupiter-family comets (JFCs). Active objects are rare in large part because they are difficult to identify, so we ask volunteers to assist us in searching for active bodies in our collection of millions of images of known minor planets. We produced these cutout images with our project pipeline that makes use of publicly available Dark Energy Camera data. Since the project launch, roughly 8300 volunteers have scrutinized some 430,000 images to great effect, which we describe in this work. In total, we have identified previously unknown activity on 15 asteroids, plus one Centaur, that were thought to be asteroidal (i.e., inactive). Of the asteroids, we classify four as active QHAs, seven as JFCs, and four as active asteroids, consisting of one main-belt comet (MBC) and three MBC candidates. We also include our findings concerning known active objects that our program facilitated, an unanticipated avenue of scientific discovery. These include discovering activity occurring during an orbital epoch for which objects were not known to be active, and the reclassification of objects based on our dynamical analyses.

Effect of Distance between Double Glazing on the Performance of a Solar Thermal Collector

In this research paper, an attempt has been made to come across the effect of distance between double glazing on the efficiency of a solar thermal collector. Experiments were carried out on an active solar energy demonstration system (ET 200). Commercial glass pane of 3 mm thick having the same dimensions as that of the apparatus was placed above the collector at a distance of 2 cm, 4 cm and 6 cm. Tests were done with and without the added glass. Experiments were performed for double glazing with two positions of the light meter. In one position, it was placed in the middle of the collector surface. While, in the other, the light meter was placed in the middle of the added glass. To study the effect of double glazing on the performance of the solar collector ET200, the correct position of the light meter was to place it exactly in the middle of the additional pane under the lamp. Double glazing doesn’t enhance the performance of the solar collector because of the high resistance of the system glass air glass. The efficiency of double glazing solar collector decreases with increasing the distance separating the two glasses.

“En-Solex”: A Novel Solar Exoskeleton for the Energy-efficiency Retrofitting of Existing Buildings

The energy retrofitting of the existing building stock is one of the current challenging strategic objectives on the way to the European target of climate neutrality by 2050. According to the Renovation Wave plan, around 35 million existing buildings need to be upgraded to the highest energy efficiency level by 2030, and innovative technological solutions are required to achieve this ambitious goal. This paper proposes a novel solar exoskeleton for the energy and architectural retrofitting of existing buildings, called En-Solex. The system, which consists of an external steel frame that wraps around buildings like a double skin, combines passive solar gain control (shading and greening) with high-efficiency active solar systems (PV panels) optimised for integration into existing building facades. The energy-saving potential of the system with different façade configurations is evaluated on a multi-family residential building located in a Mediterranean climate. The dynamic energy simulations show that the proposed solution can reduce the energy demand for space heating and cooling by 33.4% and 25.5% respectively. The En-Solex system integration combined with generator replacement results in a maximum heating and cooling reduction equal to 80.7% and 59.6% respectively. The surplus of electricity generated, thanks to the integration of RES, can lead to a net plus target, with the building exceeding its average annual electricity demand.

ANALYZING HEAT TRANSFER FLUIDS FOR IMPROVED SOLAR WATER HEATER PERFORMANCE

The First Chapter, discussed the Research background in the first section due to its potential to lower carbon emissions and energy costs, the use of solar water heaters for an environmentally friendly power alternative has increased. Also, it explained Current issues in that section Although rooftop water heater technology has advanced, choosing and optimizing heat transfer fluids (HTFs) continues to be a difficult task. The Second Chapterexplained first section is Passive solar water heating system in a passive solar water heating system uses the concept of radiation from the sun to heat water for domestic, commercial, or industrial usage without the use of active mechanical equipment like pumps or fans. It has also discussed Active solar water heating system as well as aspects affecting the performance of a solar water heater. Effective implementation of the Simulink model of the solar water heater has been adequately structured and interpreted. Additionally, proper implication over the entire work has been structured within this paper.

Indoor thermal comfort comparison between passive solar house with active solar heating and without active solar heating in Tibetan

Passive solar house technology has been spread for many farmers and herdsmen to improve the indoor thermal environment in Tibetan. However, due to lackage of fuels and arid cold in winter, dry cow dung and coal are popularly fired in stove in passive solar houses, which leads to indoor air pollution and poor indoor comfort. For improving indoor thermal comfort of Tibetan, an active solar heating system which consists of 7 sets of tandem solar water heaters with 30 glass evacuated solar tubes, low temperature floor heating and circulation controller was developed and tested for a common house without insulation in Gan-nan Tibetan area. Its indoor environment was compared and evaluated by PMV-PPD and LPD method to that of the same passive solar house heated by coal stove. On sunny, cloudy and snow days, the active solar heating system provided 113.1, 46.4 and 26.3 kWh of heat to room. The indoor humidity and wind speed of the experimental building were better. The indoor temperatures were 17.2-20.7, 14.9-20.5 and 11.0-14.8°C, while the compared building were 8.9-14.8, 10.1-12.1 and 7.2-10.5°C. The maximum temperature difference between head and ankle were 1.7, 1.6 and 0.9℃, and the compared building were 4, 4 and 4.7℃. The PMV-PPD on sunny day were class I and II; on cloudy day were class I, II and III; on snow day was class III. On sunny and cloudy days, the LPD were class I, on snow day was class I, II and III. The PMV-PPD and LPD for typical days of the compared building were class III. During the 179 days, the mean indoor temperature exceeded 14 ℃ for 81 days, the solar active heating system provided 12471 kWh of heat to room. The CO2 emission reduction was 12905 kg. The system's dynamic payback period were 2.57 years.

Modeling and comparative assessment of solar thermal systems for space and water heating: Liquid water versus air-based systems

This work pertains to the transient modeling and comparative study of active solar thermal space and water heating systems using liquid and air-type solar thermal collectors as the main energy source. The study utilizes TRNSYS to simulate the two systems in the context of Taxila's weather data (located at 33.74°N, 72.83°E), with the goal of meeting peak space and domestic water heating demands of 20 kW and 200 lit/day, respectively. The liquid water-based system (S-1) is primarily composed of a liquid solar collector, thermal storage, an auxiliary heater, connections to the hot water supply, and the space heating load through a water–air heat exchanger. In contrast, the air-based system (S-2), employs a pebble bed storage to store heat extracted from the solar thermal air collector. The heated air is subsequently used directly for space heating and passed through an air–water heat exchanger for water heating. Dynamic simulations of both systems span the entire winter season, and various performance metrics, including solar fraction, primary energy savings, and solar collector thermal efficiency, are computed. The results revealed that at the same collector area, the liquid water-based system (S-1) shows a higher solar fraction than the air-based systems (S-2) while the primary energy savings of the S-1 resulted in lower values than S-2 at smaller collector areas (< ∼30 m2) but surpasses the S-2 with increasing collector size. The optimal collector tilt for both systems is determined to be 50°, while specific storage volumes corresponding to maximum primary energy savings are estimated to be 100 and 40 L/m2 for S-1 and S-2, respectively.

Active solar heating system for residential building in Algeria An energetic economic and environmental investigation

In this work we used a typical single family house in Algeria as an example, the influence of building type on the energetic efficiency of an integrated solar combisystem (SCS) is determined by means of numerical simulation using TRNSYS software program. We considered two types of buildings, which have the same size and the same orientation. The first one is a low energy pilot house performed by CDER 'Centre de Développement des Energies Renouvelables' and CNERIB 'Centre National d’Etudes et Recherches Intégrées du Bâtiment' in the framework of MED-ENEC project, however, the second considered house is a virtual building; in which the walls are of the conventional type in Algeria. Based on the obtained results, it is outlined how the total system load can be decreased by adopting some solar architecture techniques. The analysis of the auxiliary energy required by the solar combi system and the average solar fraction; shows the profitability of the SCS application in Algeria, especially in the case of low energy house. Furthermore, the economic aspect and the environmental impacts of the integrated solar heating system have been investigated. The equity payback and greenhouse gas 'GHG' emissions have been estimated by means of a numerical simulation using the powerful tools of the RETScreen free software program. The obtained results showed that the equity payback is strongly dependent on the fuel used by the conventional heating system. In the case, where the heating is assured by the gasoil, the equity payback is around the half of the project lifetime. From the environmental standpoint, the solar application is entirely advantageous. In addition, the natural gas is the most favourable conventional energy resource, with a minimum yearly GHG emissions compared to electricity and gasoil.

Ten questions concerning planning and design strategies for solar neighborhoods

Planning of neighborhoods that efficiently implement active solar systems (e.g., solar thermal technologies, photovoltaics) and passive solar strategies (e.g., daylight control, sunlight access through optimized buildings' morphology, cool pavements, greeneries) is increasingly important to achieve positive energy and carbon neutrality targets, as well as to create livable urban spaces. In that regard, solar neighborhoods represent a virtuous series of solutions for communities that prioritize the exploitation of solar energy, with limited energy management systems. The ten questions answered in this article provide a critical overview of the technical, legislative, and environmental aspects to be considered in the planning and design of solar neighborhoods. The article moves from the categorization of “Solar Neighborhood” and the analysis of the state-of-the-art passive and active solar strategies to the identification of challenges and opportunities for solar solutions’ deployment. Insights into legislative aspects and lessons learned from case studies are also provided. Ongoing trends in solar energy digitalization, competing use of urban surfaces, and multi-criteria design workflows for optimal use of solar energy are outlined, emphasizing how they generate new opportunities for urban planners, authorities, and citizens. A framework is introduced to guide the potential evolution of solar neighborhoods in the next decade and to support the design of urban areas and landscapes with architecturally integrated solar energy solutions.

Renewable Energy Guide for Renovation of Existing Residential Buildings: Feasible Architectural Integration of Active Solar Energy Systems

Renewable Energy Guide for Renovation of Existing Residential Buildings: Feasible Architectural Integration of Active Solar Energy Systems

A climate sensitive design approach to BIPV: Investigating the nexus between solar energy and thermal comfort in cities in Sweden and Cyprus

The research performed attempts to answer the question of how building integration of active solar systems may affect the thermal comfort in open areas and the interstitial space between buildings in urban environments. This is done by using computer simulation and in-situ observations at the extreme northern and southern geographies of Europe, namely in Luleå, Sweden and in Limassol, Cyprus. A typical example of the urban grid of each city is chosen and active solar systems are integrated on the facades of buildings, respectively foreach case. The thermal conditions at street level are then simulated, using Envi-MET, before and after systems integration, with the aim of assessing the differences between low and high insolation conditions, using the Physiological Equivalent Temperature (PET) indicator. Subsequently, the thermal conditions in the public space between buildings were once again assessed, with reduced emissivity values for the building integrated PV panels. The results point to the fact that the building integration of PVs lacking low emissivity coatings can have an impact in the thermal comfort of users in the locations specified, especially in the summer, wherein it is shown to be negligible in the southern case study but more significant in the northern one.

Co-optimization of passive building and active solar heating system based on the objective of minimum carbon emissions

Co-optimization of passive building and active solar heating system based on the objective of minimum carbon emissions

Mejora del desempeño térmico de colegios en la Región Altoandina del Perú. El caso del “módulo prefabricado aula tipo heladas - PRONIED”

Faced with the qualitative and quantitative deficit of educational infrastructure in Peru’s rural high Andean areas, in recent years the Peruvian State has been investing in and supporting modular solutions, seeking efficiency in the construction processes. The specific proposal, with special emphasis on bioclimatic design, is the "Prefabricated Frost-type Modular Classroom". However, users have been expressing discomfort with these new facilities. This study shows the measurement process carried out on a built module, which allowed calibrating and validating the model using simulation software, to propose improvements in the design that may contribute to future constructions. Taking the adaptive thermal comfort model as a reference, it was confirmed that indoor temperatures were below thermal comfort limits in the early hours of the morning and well above them close to noon, by around 6 ºC and 7 ºC respectively. With the application of complementary bioclimatic strategies, it was possible to considerably improve indoor thermal conditions, although not enough to reach comfort early in the morning. This is because the night-time outdoor temperatures are very low, the building is uninhabited all night long, there is no thermal mass in the envelope, and there are no active solar systems or mechanical air conditioning.

Phase change materials (PCMs) in solar still: - a review of use to improve productivity of still

This study examines the utilization of phase change materials as latent heat storage devices to boost the output of solar stills. These results show that compared to a solar still without phase change material, a passive solar still equipped with phase change material can boost its yield up to 120%. An active solar system equipped with phase change material can enhance productivity by as much as 700%. These findings show that productivity rises with PCM mass and declines with salty water bulk. Additionally, it is discovered that the PCM performs worse during the day than at night. The most often used PCMs in productivity improvement studies were likewise found to be organic PCMs (like paraffin), with inorganic and eutectic PCMs garnering very little attention. From the present study it is clear that most of researchers used paraffin as a PCM. Also mixing of nano particles (such as silicon oil and Cu nano particles) in the PCM gives better result. Paraffin wax with nAl2O3 enhanced the production by 60.53%.