Passive Solar Technology Research Articles

Computational studies on the airflow developed by the building-integrated passive solar energy system

Ventilation and cooling demand are expected to rise in the next decades. Sustainable standalone solar passive air ventilation technique could be one of the clean options. In this study, a building-integrated passive solar energy technology (BIPSET) consists solar photovoltaic (PV) and solar still, was implemented for attaining multiple outputs, such as air ventilation, power and clean water in a building prototype proposed based on Chief Minister's solar powered green house scheme, Government of India. Solar PV and solar still were connected separately with single chimney using necessary duct connections. The heat gain in the PV panels was used for air ventilation inside the building. Computational fluid dynamics analysis was carried out in SOLIDWORKS-2017 Flow simulation software to study the airflow behaviour, such as air change per hour, heat gain and efficiencies in the building-integrated system. The results are in good agreement with experimental values for both sunny and cloudy conditions. This solar still duct arrangement reduced the airflow inside the building in noon hours by 30%. However, it improved the airflow by 8% in the evening hours. The present system is in accordance with standards like ASHRAE 62.1–2010 and GRIHA, which indicates its commercial applicability. Moreover, the environment analysis indicates that the system offers CO2 savings of 17.5 kg/year by adopting passive air ventilation. A modified integrated system was proposed to utilize the heat energy from the solar still for air ventilation by altering the duct arrangements.

Analysis of Passive Solar Desalination Technology Route

Analysis of Passive Solar Desalination Technology Route

Impact of Integrating Solar Technique On Buildings'thermal Comfort and Energy Consumption: A Numerical Study

In the context of shrinking non-renewable energy resources and reducing greenhouse gas emissions, it turns out necessary to drop energy consumption and move towards renewable energy sources. In this regard, solar energy being an abundant source of energy, it can play an important role in the building energy supply. This energy supplement can come from passive solar technologies, of which the Trombe wall is one of the passive models most used in the building envelope, whose main role is to ensure net gains. Thereby, the main aim of this study is to highlight the use of a simple method to reduce the buildings heating demand. For this, a 3-D model was developed through scSTREAM V2020 software to investigate the thermal performance of a classical Trombe wall in winter while targeting desirable indoor thermal comfort conditions. In addition, studies have been performed to optimize the energy consumption It turned out that, in the presence (respectively absence) of solar irradiation, the Trombe wall acts as a solar absorber (respectively a heat source).

Relation of Global Solar Radiation with Temperature, Rainfall, Sunshine Duration and Clearness Index at Western Himalayan Region, Nepal

The global solar radiation is measured at the horizontal surface by calibrated pyranometer at Jumla(29.27°N to 82.18°E, 2514.0m). The effect of different physical as well as meteorological parameters to the intensity of global solar radiation was analyzed. This paper compares global solar radiation with sunshine duration, temperature, and rainfall and clearness index. This paper also explains the monthly, seasonal variation of global solar radiation. The annual average global solar radiation is 18.36MJ/m2 /day which is sufficient to promote solar active and passive solar energy technology at Himalaya terrain Jumla and other similar geographical locations. This novel result can be used for location of similar meteorological and geographical characteristics at which solar data are not available.

Trombe wall for a residential building in Sichuan-Tibet alpine valley – A case study

Trombe wall (also called T-Wall) as a reliable renewable energy system has attracted increasing attention from both academics and engineers under the current energy crisis. This study then focused on a Tibetan dwelling retrofitting in the Sichuan-Tibet Alpine Valley, adopting T-wall as a passive heating solution. We investigated a classic T-wall in the target building based on field measurement, orthogonal experiment, and numerical simulation methods. It was known that the maximum average indoor temperature of the master room can reach 18.87 °C in the coldest month (January) of the Sichuan-Tibet Alpine Valley. Six key influencing factors were analyzed accordingly, including the south T-wall-to-wall ratio, inlet/outlet height, glazing inclination angle, storage wall thickness, storage wall material and cavity gap. Among those analyzed factors, it was obtained that the highly significant factors are the south T-wall-to-wall ratio and glazing inclination angle. The larger the proportion of the south T-wall-to-wall ratio, the better the indoor temperature is. The best glazing inclination angle was obtained as 100 for the target residential building under the local conditions. Solar passive technology as a cost-effective solution can improve the indoor thermal environment of the Tibetan dwellings in the Qinghai-Tibet Plateau. The total annual energy consumption of the Tibetan dwelling using the optimal combination can be reduced by about 72% compared to that of the existing Tibetan houses. The research outcomes can provide a practical guide on the future design of passive solar technologies.

Investigation on a building-integrated passive solar energy technology for air ventilation, clean water and power

The development of an integrated solar energy system with multiple outputs is necessary for achieving sustainability for countries like India. A building-integrated passive solar energy technology (BIPSET) is developed for the generation of power, and water in addition to the air ventilation for the attached building prototype. The building prototype is scaled down to the model of the living room proposed in the “Chief Minister’s solar-powered green house” scheme, Govt. of Tamil Nadu, India. The system consists of solar photovoltaic (PV) and solar still, integrated with chimney. Experimental analysis shows an average of 12 air changes per hour of ventilation inside the room using the thermal energy gained by the solar PV in the BIPSET. Daily average inlet air velocity of 0.14 m/s is measured in the windows and is in accordance with the international standard ISO 7730:2005. The electrical efficiency of the PV system is improved from 4% to 17% in BIPSET compared to standalone PV System. Solar still performance is improved from 3 to 11% in the integrated system. Energy, environment and economic analysis are carried out for the BIPSET. The energy payback for the solar PV integrated with chimney is better than the standalone PV system. Lifecycle assessment is carried out for the BIPSET following CML-2001 methodology using SOLIDWORKS sustainability tool. This study implies that the present system is environment-friendly during its operation and its end of life. From the economic analysis, the unit cost of electricity for the solar PV integrated with chimney is 18% less when considering 30% government subsidiary for PV panels. The analysis indicates that the present integrated system is technically and economically feasible and is environment friendly.

Ultrahigh-efficiency desalination via a thermally-localized multistage solar still

Passive vapor generation systems combining interfacial solar heating and vaporization enthalpy recycling enable high-efficient low-cost desalination.

Evaluation of low-impact modular housing using energy optimization and life cycle analysis

This paper presents life cycle analysis of the container-based single-family housing and combines energy analysis and optimization, life cycle assessment and life cycle costing. The proposed models include the container code (CC), designed to Canadian national building code as reference model, and an improved container (IC) incorporating passive solar technologies. Utilizing passive design strategies results in approximately 79% reduction in annual operational energy consumption for the improved case. The life cycle assessment considers the total energy use and global warming potential over 60-year lifespan. Three life cycle phases are considered: pre-use, use and operation, and end of life. As a result of envelope upgrade, the IC offers 77% reduction in life cycle energy use and global warming potential (GWP) than the CC. However, the envelope upgrade requiring greater energy intensity through industrial processing of additional building materials led to higher environmental impact, approximately 65,370 kWh of embodied energy and 20 t of CO2 eq of GWP embodied carbon emissions for the improved container at pre-use phase. In terms of life cycle cost, IC shows less than 10% total cost savings as compared to CC. This study, however, proves that integrating passive solar design techniques in building not only results in reduced energy consumption but rather translates to reduction in life cycle environmental impacts and life cycle cost building systems, which is, in this case, a modular container housing.

Towards an optimized zero energy solar house: A critical analysis of passive and active design strategies used in Solar Decathlon Europe in Madrid

Solar Decathlon is an international multidisciplinary competition for designing, building and operating Zero Energy Solar House. Based on the existing evaluation framework, this research identifies 7 key decisions and 24 passive and active strategies that lead to an optimized Zero Energy Solar House with better architecture, comfort condition and electrical energy balance performance: selecting passive strategies regarding shape, function layout and microclimate organization, adopting solar systems and heating, ventilation and air-conditioning systems as active strategies, integrating the passive and active with prefabrication systems, and finally evaluating the project against sustainability (energy payback period). Focused on 2010 and 2012 Solar Decathlon Europe in Madrid, this research critically reviewed 33 involved projects using this framework. Furthermore, the research correlated the 24 strategies with their performance results in the competition through multi-criteria analysis. The review generated passive-active integrated empirical models for an optimized Zero Energy Solar House in Mediterranean climate conditions. Beyond the particular competition and climate, the research found five important lessons for integrating passive and active technologies for a solar house. The framework proposed by this research, and the strategies and lessons learnt from reviewing the Solar Decathlon Europe competitions can help to transfer the technologies and related knowledge gained from experiments into practice. • A framework with 7 key decisions and 24 strategies for an optimized ZESH is established. • Thirty-three solar houses involved in Solar Decathlon Europe (SDE) in Madrid are examined. • Passive-active integrated empirical models for an optimized ZESH are generated. • Five important lessons for integrating passive and active solar technologies are extracted. • The research helps to transfer the experimental technologies and knowledge into design practices.

An investigation on the climate-responsive design strategies of vernacular dwellings in Khams

Successful building design balances ambitious environmental requirements and residential comfort by considering the regional culture, economic level, natural environment, indoor thermal comfort and energy consumption. Taking dwellings as a case study, this paper examines the potential of improving indoor thermal comfort through field investigations of indoor environments in the Tibetan area. Settlement location and layout designs, combined with the natural environment, religious culture, synchronous optimization of structural seismic performance and enclosed structure, and a semi-open space setting making full use of passive solar energy technology, is a major strategy for climate-responsive design in Khams that also meets local economic levels and modern living needs. The results show that this strategy can achieve 5 h with air temperatures over 16.4 °C (from 12:30–17:30) in a comfortable thermal environment without the consumption of fossil energy, while in the evening, the thermal environment indicators in the major living space remain stable with low heat loss, indicating that an appropriate heat source from local bioenergy can achieve indoor thermal comfort. Overall, the dwellings in Khams with abundant solar energy and a lack of fossil energy are very well adapted to local climate conditions.

Are Trombe walls suitable passive systems for the reduction of the yearly building energy requirements?

Efficient low consumption buildings require the building envelope to be scrupulously designed from an early stage. Passive solar technologies, such as the Trombe wall, can contribute to the reduction of the heating energy demand and, if properly operated, they can also impact the building summer behaviour. The use of such a solution has been limited, especially in warm climates, as severe problems of indoor overheating can occur even beyond the cooling period. Through the dynamic simulation software DesignBuilder, the authors investigated the energy performance of two different residential buildings equipped with a Trombe wall in different climatic contexts. The authors proposed the adoption of proper ventilation strategies to further reduce cooling needs. The validity and effectiveness of the proposed solutions was verified in warm climates where the Trombe reduced heating requirements by up to 71.7% and decreased the cooling energy demand by 36.1%. In a cold climate, heating savings were 18.2% with a cooling energy reduction of 42.4%. The study highlighted the fundamental importance of the definition of proper ventilation strategies based on climatic parameters to prevent drawbacks in intermediate seasons, with an evident limitation of the system performance.

Evaluating potentials of passive solar heating renovation for the energy poverty alleviation of plateau areas in developing countries: A case study in rural Qinghai-Tibet Plateau, China

Energy poverty refers to a situation that people cannot access and use energy safely. It is a major challenge for the global energy system because of its negative impacts on household income, health, education, gender equality and environmental conditions. To solve this problem, many countries advocate the development and promotion of passive solar technology, but the effectiveness of them for energy poverty mitigation has not been evidenced. Therefore, based on empirical studies in the rural areas of Qinghai-Tibet Plateau, this paper aims at investigating the effectiveness of passive solar heating renovation to alleviate energy poverty in rural plateau areas. Specifically, this paper compared and analyzed the coal consumption and indoor air quality during the heating period before and after the renovation of a single-storey building. Further, based on the IES-VE numerical simulation, this paper analyzed the impact of building envelope structure performance on indoor air temperature. The results show that after building renovation, the coal consumption during the heating period could be reduced by 97 kg/week, while the indoor average temperature of two bedrooms were increased by 4.8 °C and 1.7 °C respectively. Setting up the coal stove as an auxiliary heating device, can alleviate the defects of insufficient heating of passive solar energy technology, and indoor temperature could be further improved. However, indoor air quality was lowered because of the high PM2.5 concentration. In contrast, improving envelope performance could further improve the average temperature of two bedrooms and the sunspace to 16.7 °C, 15.9 °C and 15.6 °C, meeting the requirements of indoor space heating. In general, passive solar heating could achieve satisfactory results, but to alleviate energy poverty effectively in rural plateau areas, further attention should be paid to other technical, economic, social and policy issues.

Study on the Thermal Performance of a Hybrid Heat Collecting Facade Used for Passive Solar Buildings in Cold Region

Passive solar technologies are traditionally considered as cost-effective ways for the building heating. However, conventional passive solar buildings are insufficient to create a relatively stable and comfortable indoor thermal environment. To further increase the indoor air temperature and reduce the heating energy consumption, a hybrid heat collecting facade (HHCF) is proposed in this paper. To analyze the thermal performance of the HHCF, a heat transfer model based on the heat balance method is established and validated by experimental results. Meanwhile, the energy saving potential of a room with the HHCF is evaluated as well. When the HHCF is applied to places where heating is required in the cold season while refrigeration is unnecessary in hot season, the HHCF can reduce the heating need by 40.2% and 21.5% compared with the conventional direct solar heat gain window and the Trombe wall, respectively. Furthermore, a series of parametric analyses are performed to investigate the thermal performance of the room with HHCF under various design and operating conditions. It is found that the thermal performance of the HHCF mainly depends on the window operational schedule, the width and the absorptivity of heat collecting wall, and the thermal performance of the inner double-glass window. The modeling and the parametric study in this paper are beneficial to the design and the optimization of the HHCF in passive solar buildings.

Impact of Temperature, Rainfall and Clearness Index on Global Solar Radiation at Nepalgunj in Nepal

This paper reports the first experimental results on global solar irradiance measured at the horizontal surface since 2017 using calibrated Pyranometer-2 at Nepalgunj (Lat.28.05°N, Lon.81.62°E) which is about 150m from the sea level. This paper explains the impact of temperature, rainfall and clearness Index on the intensity of global solar irradiation. The annual average measured value of GSR 16.02 MJ/m2/day which is sufficient to promote solar active and passive solar energy technology at Nepalgunj and other similar geographic allocations. The results of this research can be utilized for the conformation of variation of solar radiation with meteorological parameters and can be used for location of similar meteorological and geographical sites where solar data are not available.

Numerical study on the energy performance of building zones with transparent water storage envelopes

Researches on water wall passive solar technologies, especially the numerical study on the energy performance of building zones with Transparent Water Storage Envelopes (TWSEs), are reported in this paper. TWSE is a climatic adaptive building envelope consisting of visually transparent modular water containers, exterior shading devices, water supply and return pipes. It is an upgraded water wall that can serve both as an energy efficient facade and an auxiliary water cistern in a building. Currently the energy simulation involving transparent water walls cannot be explicitly done in all energy simulation programs because transparent envelopes are always predefined as the surfaces without thermal mass due to the embedded algorithms complied with ISO15099 standard. A numerical approach based on the integrated energy and computational fluid dynamics (IE&CFD) simulation was developed for solving the energy simulation problem related with TWSEs. A simplified optical model of TWSE was proposed and validated through light transmission testing. Meanwhile, cooling and heating loads of a zone with TWSEs and conventional glazing in summer and winter months were studied. The thermal performance of a TWSE relative to the conventional glazing was also investigated via the comparative thermal box testing. Based on the simulation and testing results, it reveals that TWSEs can exceed most high performance coated glazing with regard to solar radiation control, and they are also exceptional energy efficient transparent envelopes that can outperform the ASHRAE standard window and conventional glazing in terms of cooling and heating load reduction as long as being configured and operated properly according to their physical characteristics and outdoor climatic condition. Furthermore, the innovative technical paradigm of TWSEs, along with the numerical approach developed for their energy simulation, demonstrates a wide range of versatility to be implemented in research and practice for ultra low energy buildings.

Yield of Leafy Greens and Microclimate in Deep Winter Greenhouse Production in Minnesota

The Deep Winter Greenhouse (DWG) uses passive solar technology to create an environment where cold tolerant crops like leafy greens can be grown during the winter to satisfy consumer demand for fresh local produce year-round and increase revenue for farmers. A cultivar trial consisting of 12 different salad greens was conducted in partnership with three farmers in order to determine suitable cultivars for these unique systems. Yield and days to maturity were recorded, and microclimate conditions such as light, temperature, and relative humidity were tracked throughout the season. This study included three sites from three distinct locations within Minnesota. Environmental differences among the DWG sites and within site replicates were observed. Yield also varied with micro-climate. The trials demonstrate that lettuces and greens such as ‘Florence’ (Lactuca sativa L.), ‘Salanova’ (Lactuca sativa L.), and ‘Vitamin Green’ (Brassica rapa L.) generally grow well. These cultivar trials, coupled with other horticultural trials and economic analyses, will better inform recommendations for farmers growing in these unique environments.

Numerical Analysis on the Structure of Wall Implanted with Heat Pipes

A type of passive solar energy utilization technology, the wall implanted with heat pipes, with a double vacuum glass panel be set to isolate the condenser section from the outdoor environment, is studied theoretically in this paper, to improve the utilization of solar energy on building walls with external thermal insulation in winter in northern China. A two-dimensional transient heat-transfer model is developed to analyse this instruction and then it is solved by using finite difference method (FDM). Numerical calculation on this construction indicates that, the temperature of the inner surface increases by 12.4 degrees with the glass panel in typical climate of Beijing, more than the figure that is 5.8 degrees at most without the structure. It can improve the indoor thermal environment effectively.

Modeling of heat transfer processes in ventilated enclosing structures in stationary conditions

One of the ways to increase the energy efficiency of the housing and communal enterprise and solve the problem of space heating is the construction of «Passive houses», which contain elements of structures that effectively absorb the energy of solar radiation. The object of the study is the «Passive house», which is a building in which thermal comfort (ISO 7730) is achieved solely by additional preheating (or cooling) of the fresh air mass. This is necessary to maintain high quality air in the rooms, without additional recirculation.The analysis of heat exchange processes in ventilated enclosing structures is carried out and the calculation methods for their design are analyzed. The application of passive solar heating technology in Ukraine's climatic conditions will provide up to 50 % of the heat needs.It is determined that the movement of outdoor air in the ES (open enclosing structures) along the wall of the house leads to heat loss, but air in the ventilated layer will prevent the formation and accumulation of condensate. This will allow in winter to maintain the thermal properties of the outer layer of insulation at home, reduce the cost of heat for heating and prevent the formation and development of fungal mold.The peculiarities of heat exchange processes in building structures with ventilated channels are studied. On the basis of the analysis of calculation methods for ES design, it can be stated that the classical method for evaluating heat exchange processes is based on the equations for the thermal balance of air for an infinitesimal volume dx. But when using this equation, it is impossible to take into account the distribution of radiant and convective heat flows, and also to estimate the effect of energy losses.The paper proposes a mathematical model that will allow to determine changes in air temperature along the ventilated layer of enclosing structures and to quantify the intake or loss of heat to the room during the cold season.

Heat storage wall made of concrete and encapsulated water applied to mass construction social housing in temperate climates

In Argentina there is a serious housing shortage. The National State responds to this shortage in a quantitative rather than in a qualitative way, avoiding low maintenance architectural and technological solutions for this problem. For this purpose, the passive solar technologies are a truly viable alternative. Therefore, this work presents the design and thermal performance of heat storage walls (HSW) made of mixed materials (concrete and water) for heating mass construction housing built by the National State of Argentina. They are prepared to be included in modules (1.2m×2.4m) on the equator-facing sides since they are made of storage mass made with industrialized stackable pieces. The storage mass is made of concrete with encapsulated water in PVC pipes and it is covered with a single-glazed covering. In this work, the technological design, the industrialization, manufacture and assembly stages, and its performance are presented. Simulations of the systems incorporated into a house were carried out and they were then compared to the most widespread technologies (solid concrete walls). Experimental scale measurements of these systems were also made in a 1.08m3 insulated enclosure. The simulations did not show very significant differences among the analyzed systems, but they allowed us to define the use of single glazing as a transparent covering. The measurements show the different loading dynamics of each type of wall and confirm a difference of 2°C among the internal temperatures, recorded inside the enclosures in favor of the mixed storage wall. The carried out works enabled us to install those systems in social housing in the Province of Buenos Aires, Argentina.

The passive solar heating technologies in rural school buildings in cold climates in China

Heating is difficult in rural school because of its cost. These areas, however, are rich in solar energy potential and should look toward passive solar designs. In this study, the indoor temperatures of three different passive solar technologies were examined. Results of calculations were verified by on-site experiments allowing on use of these models to draw further conclusions. In analyzed schools, modes of operation and functional requirements are different and the use of verified model permitted to determine the optimal type of passive solar technology. The passive heating techniques were ranked for different buildings and collected in four classes: most suitable, more suitable, less suitable, and non-suitable.