Passive Solar Research Articles

Analysis of thermal energy storage system for energy saving reconstruction of building in region with heating provision and high sunshine

This research aims to analyze the effect of phase change energy storage wall on the internal thermal environment in high-sunshine passive solar residential buildings. The residential buildings in Lhasa are taken as research objects, and the differences in indoor and outdoor thermal environments of the residential buildings in winter are first evaluated. Then, the energy storage wall model based on phase change material is constructed, the meteorological data of the winter solstice day is used to simulate, and the changes of the thermal environment in the room are detected. The results showed that the average solar radiation intensity of the dwellings in Lhasa is 441.8 W/m2, and the average scattering intensity is 156.3 W/m2. The average humidity and temperature of outdoor air are 24.4% and 1.54?C, respectively. The temperature difference of the indoor south and north bedrooms is 3.3?C, the internal temperatures of the indoor south and north walls are 13.4?C and 7.9?C, respectively, and the temperature difference is 5.5?C. After the adoption of phase change energy storage materials, the indoor temperatures of the south and north walls on the winter solstice day are 16.75?C and 16.52?C, respectively, with a temperature difference of 0.23?C. The inner surface temperatures of the south wall and the north wall increase by 25.0% and 109.1%, respectively, after adopting the phase change energy storage wall, indicating that applying the phase change energy storage wall to the passive solar residential buildings in Lhasa can effectively improve the indoor thermal environment.

LCCO<sub>2</sub> AND THERMAL ENVIRONMENT OF LIVING ROOM MODEL FOR PASSIVE SOLAR HOUSE WITH THERMAL MASS

Introduction: Considering the relationship between the environmental load and the environmental quality is very important in design of the ecological housing. Moreover, the importance of study from the viewpoint of lifecycle is increasing. This study aims to clarify relations between LCCO2 and thermal environment in passive solar house with thermal mass. Method: Firstly, the settings for the model of living room with various combinations of window and thermal mass are assumed. The models are mainly based on wooden structure with the wide frontage facing south to gain solar heat. The supposed site is in suburb area of Tokyo, Japan. Three variations of the south window are set by size and position of opening and depth of eaves. Besides, four compositional variations of thermal mass to store solar heat are set by position and amount of reinforced concrete element. Consequently, the twelve models are set for following investigations. Secondly, the amount of embodied CO2 for each model is calculated by LCA tool offered by the Architectural Institute of Japan. Thirdly, the amount of operating CO2 emitted from the air-conditioning load is calculated by the Solar Designer which is a thermal environment simulation tool. Furthermore, the qualities of thermal environment focusing on the change of room temperature on sunny day in winter and summer are investigated by considering the Degree・Hour (D・H) which integrates the fluctuation of room temperature. Finally, the amount of LCCO2 is calculated by combining the embodied and operating CO2, and then, the relationships between LCCO2 and thermal environment quality by D・H are clarified. Results: 1) The model AS which has the smallest thermal mass and window indicates the smallest embodied CO2. On the other hand, the model CL which has the second largest thermal mass and the largest window shows the largest embodied CO2. These are regarded by differences for the repairing cycle of element. 2) The models of A, B and C which have larger thermal mass tend to indicate smaller operating CO2 according to reduction of window size. However, only the model D with the largest thermal mass shows a different tendency that indicates smallest operating CO2 in the case with medium window size. 3) The room temperature’s change tends to become smaller along with increase of thermal mass. However, the model DS which has largest thermal mass and smallest window shows minimum D・H in winter which is a stable environment in low temperature. 4) For the relations between LCCO2 and thermal environment, the models AS, BM, CM and DL which have different combinations of thermal mass and window size indicate smaller LCCO2 with an appropriate D・H combination in winter and summer. Especially, the model AS and DL have contrastive difference for the passive design strategy regarding with the less or more thermal mass and the smaller or larger window for solar gain, in addition to their differences for the combination of embodied CO2 and operating CO2. This result means a “trade-off” relations between LCCO2 and thermal environment and shows alternatives for design regarding the balance of thermal mass and window with proper combination of environmental load and quality.

Analysis of the potential use of Trombe walls in Brazil: design recommendations

In this paper, the thermal performance of a standard environment was evaluated based on the use of a Trombe wall with different configurations and types of use, as the potential for using this passive strategy is still little studied in Brazil. This device is capable of absorbing energy from solar radiation by heating the air in this greenhouse and this heated air can be directed to the interior or exterior of the building depending on the purpose. This air can be used to heat the room or cool it by means of natural ventilation. The analysis of this research was based on a series of computer simulations using the EnergyPlus software, version 7.0 in order to quantify and classify the thermal performance of a standard environment equipped with this component, under the various construction configurations. Both for heating and cooling environments. The use of Trombe walls improved the thermal comfort of users in buildings located in Brazil, depending on the climate where they are located, promoting natural ventilation and passive solar heating, allowing the potential of this device to be investigated in the most diverse Brazilian regions.

Design optimization of a building attached sunspace through experimental monitoring and dynamic modelling

In Europe, buildings are responsible for 40% of the energy consumption and 36% of the CO2 emissions. Space heating largely contributes to these energy and climate impacts. Passive solar heating systems, as sunspaces, can contribute to increase solar heat gains, reducing space heating energy demand and the related use of fossil fuels. Careful design and local climatic considerations are essential to optimize the performance of sunspaces. In this study experimental field monitoring, dynamic modelling and steady-state methods are applied to analyse the thermal behaviour of an attached sunspace in an Italian existing building, as well as its potential contribution to the building’s energy balance. Design modifications for improved thermal performance of the sunspace are investigated. The results show overall agreement between the dynamic modellings and experimental monitoring of the sunspace and indicate that the sunspace’s indoor air temperature and hence solar energy gains are significantly increased with the design modifications, in contrast to the existing configuration. Maximum temperatures between 44 and 48 °C were observed for the existing and a modified alternative of the analysed sunspace. The dynamic simulation model and design modifications presented in this study can serve as basis for assessment and optimal configurations of sunspaces in their design stage.

Тепловий режим будівлі з пасивною системою опалення

One of the largest energy consumers for many countries over the world is the housing and communal sector, so energy saving and the use of renewable energy in this sector make it possible to achieve significant energy savings. The realization of the energy saving potential is complicated by the great diversity of the existing housing stock, which requires an individual approach in solving the problems of energy saving and energy supply of buildings. The experience of Sweden, Finland, Germany and the USA in the use of passive solar heating systems is useful for Ukraine. These systems, when properly designed, have an efficiency of up to 60% and cover more than 50% of the heating load. However, the insufficient number of publications on the efficiency and implementation of passive solar heating systems for the climatic conditions of Ukraine caused the need to simulate the thermal mode of the building with such system to determine the possibility of energy needs covering. A building model has been created using the MatLab/Simulink software. This model allows determining temperatures of enclosure structures and indoor air in connection with variable environmental parameters, such as solar radiation, ambient air and soil temperatures. The solar irradiation to the building's exterior enclosure structures was calculated for each hour of the day during the year for Kherson's climatic conditions. Based on the simulation results, the indoor air temperature oscillations amplitudes, time displacement in heat input to the building, energy needs and duration of heating and cooling periods are determined. The thermal modes of the three residential building variants are compared: without a passive solar heating system, with the Trombe wall and the Trombe wall and shading shutters. It has been determined that using of the Trombe wall reduces heating energy need of 76.9%, but leads to a significant room overheating during the warm period of the year and, consequently, to increasing of cooling energy need by 3.4 times. It is shown that using of the Trombe wall with shading shutters leads to reducing the energy demand for both heating and cooling. Keywords: Trombe wall, energy need, heating, cooling, enclosure structures.

Passive solar systems for buildings: performance indicators analysis and guidelines for the design

Data from the International Energy Agency confirm that in a zero-energy perspective the integration of solar systems in buildings is essential. The development of passive solar strategies has suffered the lack of standard performance indicators and design guidelines. The aim of this paper is to provide a critical analysis of the main passive solar design strategies based on their classification, performance evaluation and selection methods, with a focus on integrability. Climate and latitude affect the amount of incident solar radiation and the heat losses, while integrability mainly depends on the building structure. For existing buildings, shading and direct systems represent the easiest and most effective passive strategies, while building orientation and shape are limited to new constructions: proper design can reduce building energy demand around 40%. Commercial buildings prefer direct use systems while massive ones with integrated heat storage are more suitable for family houses. A proper selection must consider the energy and economic balance of different building services involved: a multi-objective evaluation method represents the most valid tool to determine the overall performance of passive solar strategies.

A Building energy simulation methodology to validate energy balance and comfort in zero energy buildings

The construction of Net Zero Energy Buildings (NZEB) is one of the objectives in the road to the low-carbon economy by 2050. NZEB design includes a reduction of current energy demands and the balance between consumption and on-site energy generation without compromising indoor comfort conditions. Building designers are using building information modeling (BIM) and building energy simulation (BES) tools to validate design decisions and to evaluate energy balance in buildings. However, the flow of information between BIM software and BES tools has not been solved yet. This work proposes a method to address the decision-making process at three different stages of the building design. Initially, the use of BIM over the architectural design process helps architects to make meaningful decisions related to the passive solar heat gains and envelop materials. Secondly, a more advanced BES is used to analyze the strategies of ventilation and the influence of heating ventilation and air conditioning (HVAC) systems. Finally, a new method to integrate water flow glazing (WFG) is implemented to increase the comfort in those areas of the building with a large area of glass. Applying the right strategy for natural ventilation can reduce the thermal loads by 45% in Summer. Using WFG minimizes the gap between indoor air temperature and operative temperature according to the results.

SUNNY HOUSE WITH A VEGETARIAN

The relevance of passive energy saving technologies in energy efficient low-rise construction in Russia is indicated. The definition of a passive house and its feature is given. Indicated that an attractive source of energy for heating the house is the energy of the sun. The definition of a solar house is given. The requirements for a solar passive house during its design are described: compact form of the house, optimal orientation of the house to the cardinal points, differentiation of glazing at home, passive use of solar energy, etc. It is noted that the most common system of passive heating of a house is to heat insulated glazed volume between nature and internal space of the house (vegetarian). The definition of a vegetarian is given, its design, features and advantages are described. Considered and analyzed various ways of heating solar houses from a vegetarian: a semi-direct, indirect, thermosiphon system with heating and circulation of warm air around the house. The classification of solar houses is discussed depending on the architectural solution for the placement of the vegetarian: a detached house with a vegetarian; a house with a vegetarian adjoining its main living space; a house located with a vegetarian under a common roof; a house with a vegetarian built into its living volume, a house with a “double shell”. The following types of vegetarians are listed: attached to an existing house, built into the house or being a “second shell” for the house. Practical recommendations for optimal work of a vegetarian are given: the need for special glazing (thermal mirror), protection from sunlight in the summer. The conclusion is made about the prospects of solar houses with a vegetarian due to the clear advantages of the passive heating system of the house and a high architectural and aesthetic level.

Adaptive thermal comfort and climate responsive building design strategies in dry–hot and dry–cold areas: Case study in Turpan, China

Recently, the construction of energy efficiency buildings has been one of the main objectives of sustainable development, especially for areas with extreme climate. In present study, the adaptive thermal comfort and climate responsive strategies in dry–hot and dry–cold areas were investigated with field measurement and questionnaire in the Turpan basin, China. First, the adaptive thermal comfort model was established to reveal the relationship between indoor thermal comfort conditions and outdoor climate. Then, the climate responsive strategies which helped residents adapt to harsh climate were concluded. The prototype of climate responsive dwellings is proposed. Finally, the effects of these strategies were investigated by field measurement of indoor thermal environment in two demonstration houses and evaluated by the proposed thermal comfort model. The results showed that residents in the Turpan basin exhibited better adaptability to the hot climate than the cold climate with the upper limits of 80% acceptability reaching 34 °C. The heavy structure envelope and constructional patterns based on the thermal adaptive behaviors of residents could improve indoor thermal environment. In summer, semi-basement was the most effective strategy to satisfy human thermal comfort, followed by night ventilation. The indoor air temperature in semi-basement was around 31 °C while outdoor temperature exhibited diurnal variation of 15.7 °C from 28.6 °C to 44.3 °C. In winter, passive solar heating and semi-basement were both effective. The indoor air temperature was higher in the bedroom located at the south semi-basement compared with other rooms. The study can provide new thoughts for designing climate friendly buildings in dry-hot and dry-cold areas.

Influence of the Airflow in a Solar Passive Building on the Indoor Air Quality and Thermal Comfort Levels

The influence of the airflow in a solar passive building on the indoor air quality and thermal comfort levels was investigated. The numerical study for a university library was conducted using a software that simulates the building thermal behavior with complex topology, in transient conditions, for evaluating the indoor air quality and occupants’ thermal comfort levels for typical summer and winter days. Solar radiation was used as a renewable energy source to increase simultaneously the thermal comfort and air quality levels and reduce building energy consumption. Regarding the solar passive building, consideration was given to all of the building structure envelope, shading devices and interior details, while in the solar active building active ventilation was used. To analyze the airflow that simultaneously provides the best indoor air quality and thermal comfort levels, a new integral methodology based on the minimization of the total number of uncomfortable hours was used. The results show that it was possible to determine an air change rate that ensures a good compromise between thermal comfort and indoor air quality. An optimal air change rate of two and three renewals per hour had been determined, respectively, for winter and summer conditions.

The Adaptability of Passive Design Strategies for Public Buildings in Shenzhen

In recent years, with increasing demands of improving public indoor environment for living in a more comfortable manner, a large number of mechanical equipment are applied to public buildings, making public buildings be major energy consumers in civil buildings. Passive technology is an effective way to design buildings of energy saving strategies. Therefore, this paper summarizes the overall energy consumption of public buildings in Shenzhen by collecting and analyzing statistical data through Shenzhen Statistical Yearbook over the years. Besides, using Ecotect’s sub-software “Weather tool” to analyze the local meteorological environment. Through the analysis of the psychrometric chart to get the different energy-saving potential used the specific six passive design strategies, the results have shown that the best combination of passive design strategies suitable for climate conditions are natural ventilation, passive solar heating, and thermal heating. Finally, these three passive design strategies are further analyzed and discussed to obtain the feasible schemes, which could provide constructive suggestions for passive energy-saving design of public buildings in Shenzhen.

Low-energy architecture in the south of Russia

For the certification of the building (establishing the efficiency class), a simplified calculation of the excess heat energy during direct solar heating of the building can be applied. This excess is possible under appropriate climatic conditions of the construction site and the parameters of translucent structures. An example of a building project with low-energy architecture for the climatic conditions of Krasnodar is given. The use of passive solar heating devices reduces energy consumption for building heating by 43% and, accordingly, reduces carbon dioxide emissions into the atmosphere.

Analysis of the Impact of the Construction of a Trombe Wall on the Thermal Comfort in a Building Located in Wrocław, Poland

Changes in climate, which in recent years have become more and more visible all over the world, have forced scientists to think about technologies that use renewable energy sources. This paper proposes a passive solar heating and cooling system, which is a Trombe wall located on the southern facade of a room measuring 4.2 m × 5.2 m × 2.6 m in Wrocław, Poland. The studies were carried out by conducting a series of numerical simulations in the Ansys Fluent 16.0 environment in order to examine the temperature distribution and air circulation in the room for two representative days during the heating and cooling period, i.e., 16 January and 15 August (for a Typical Meteorological Year). A temperature increase of 1.11 °C and a temperature decrease in the morning and afternoon hours of 2.27 °C was obtained. Two options for optimizing the passive heating system were also considered. The first involved the use of triple glazing filled with argon in order to reduce heat losses to the environment, and for this solution, a temperature level that was higher by 8.50 °C next to the storage layer and an increase in the average room temperature by 1.52 °C were achieved. In turn, the second solution involved changing the wall material from concrete to brick, which resulted in a temperature increase of 0.40 °C next to the storage layer.

Balancing daylight and overheating in low-energy design using CIBSE improved weather files

A new set of CIBSE weather files for building performance simulation was recently developed to address the need for better quality solar data. These are essential for most building performance simulation applications, particularly for daylighting studies and low-energy building design, which requires detailed irradiation data for passive solar design and overheating risk analysis. The reliability of weather data becomes paramount when building performance is pushed to its limits. Findings illustrate how principles of good window design can be applied to a case study building, built to the Passivhaus standard, and how its expected performance is affected by the quality of solar irradiation data. Analyses using test reference years were most affected by changes in the solar radiation model (up to 8.3% points), whereas for design summer years the maximum difference was 1.7% points. Adopting the new model caused overheating risk to be classified as more severe using test reference years than design summer years, prompting a discussion on the design summer year selection method. Irradiance data measured on-site were used as a benchmark to evaluate the new solar radiation model, which was found to significantly improve the accuracy of irradiance data within weather files and so the reliability of overheating assessments. Practical application: CIBSE weather files are widely used for compliance verification of building performance in the UK context. This paper tests how the introduction of a new solar radiation model in weather files will affect daylighting and overheating simulation results. Examples are given on how low-energy building design considerations driven by advanced simulation techniques can help reaching indoor visual and thermal comfort requirements.

Predicting daily diffuse horizontal solar radiation in various climatic regions of China using support vector machine and tree-based soft computing models with local and extrinsic climatic data

Knowledge of diffuse horizontal solar radiation (Rd) on horizontal surfaces is a prerequisite for the design and optimization of active and passive solar energy systems such as the solar illumination system within a building, but it is unavailable in many worldwide locations and commonly predicted by readily available climatic variables. However, reliable prediction of Rd is difficult when lack of complete or previous climatic data at the target station. This study evaluated the performance of support vector machine (SVM) and four tree-based soft computing models, i.e. M5 model tree (M5Tree), random forest (RF), extreme gradient boosting (XGBoost) and gradient boosting with categorical features support (CatBoost), for prediction of daily horizontal Rd when using limited local (Scenario 1) and extrinsic (Scenarios 2 and 3) climatic data. Six input combinations of daily global solar radiation (Rs), sunshine hour (n), maximum/minimum temperature (Tmax/Tmin) and relative humidity (RH) during 1996–2015 at 15 weather stations across various climatic rons of China were considered. The results demonstrated that, when lack of Rs, the average root mean square error (RMSE) was considerably increased across China (42.4%) in Scenario 1, especially in the (sub)tropical monsoon ron (68.3%). SVM offered the best combination of prediction accuracy and generalization capability in all scenarios, followed by CatBoost. CatBoost produced the closest daily Rd estimates to SVM and satisfactory generalization capability. In Scenario 2, CatBoost and SVM models developed with climatic data from Beijing gave the overall best daily Rd estimates over the 15 stations, while models developed with data from 14 weather stations in Scenario 3 produced even better and steadier Rd estimates across China compared with those in Scenario 2. The average computational time of SVM (6.6 s) for a single sample was approximately 1.9 times that of CatBoost (3.5 s) in Scenarios 1 and 2, while the corresponding value (842.6 s) was approximately 33.9 times that of CatBoost (24.9 s) in Scenario 3. Comprehensively considering prediction accuracy, generalization capability and computational efficiency, CatBoost is highly recommended to develop general models for daily Rd prediction in various climatic rons of China, particularly when lack of previous local climatic data.

Thermal and cost analysis of various air filled double glazed reflective windows for energy efficient buildings

The enormous amount of energy is being consumed by buildings in an attempt to deliver thermal comfort in buildings. This paper aims at reducing/increasing the total solar heat gain through various combinations of double glazed reflective windows of buildings. The spectral characteristics of six reflective glasses namely bronze, green, grey, opal blue, sapphire blue and gold-reflective glasses at a normal angle of incidence by using UV-3600 Shimadzu spectrophotometer according to ASTM E 424 standards were experimentally measured. The solar optical properties of the glasses were deduced by developing a MATLAB code using spectral data which was obtained from experiments in the solar spectrum wavelength range of 300 nm–2500 nm. Thirty air-filled double-glazed reflective windows have been studied for both thermal and cost analysis in the Indian composite climatic zone (New Delhi 28.580 N, 77.200 E). The configuration C13 (Grey reflective glass-Air gap 10 mm-Gold reflective glass) is observed to be the best air-filled double glazed window from the highest annual cost savings ($ 79.29 per annum in SE direction) and lower payback period (1.42 years) point of views among thirty double-glazed reflective glasses studied. The results of this paper are useful in the design of sustainable passive solar buildings.

Seed release by a serotinous pine in the absence of fire: implications for invasion into temperate regions.

In pines, the release of seeds from serotinous cones is primarily considered a response to the high temperatures of a fire. However, the naturalization of serotinous pines in regions where fires are rare highlights the need to quantify environmental conditions that determine seed release to allow accurate prediction of dispersal and spread risk. We investigated the conditions that break cone serotiny in Pinus radiata, a widely planted forestry species that has naturalized in temperate regions worldwide. We quantified the cone temperatures at which cones open in this species, while also assessing potential confounding effects of cone moisture and age on these temperature requirements. We compared our laboratory results with cone opening behaviour under typical field conditions during summer in Canterbury, New Zealand. Cones opened at a mean temperature of 45 °C, much higher than maximum ambient air temperatures recorded in New Zealand. We found no influence of cone age or moisture content on opening temperature. Under field conditions, cones opened upon reaching similar temperatures to those determined in the laboratory; however, passive solar heating caused cones to reach temperatures up to 15 °C higher than ambient conditions. This resulted in 50 % of cones opening in field conditions where maximum air temperatures never exceeded 30 °C. Our results highlight the need for complementary laboratory and field experiments for understanding seed release from serotinous cones. Our findings have important implications for weed risk assessments, showing that serotinous pines can release seed in temperate climates without fire.

Quantifying the effectiveness of mass proportions and the orientation for buildings on thermal performance in Tebessa, Algeria

Macro-Climate and Micro-Climate conditions have a great influence on energy consumption and thermal performance on both urban and architectural design scales. Integrating the passive strategies and measures are considered the best ways of dealing with different climatic conditions.The geometric shape and orientation of the buildings lie at the core of the passive strategies that significantly affect the thermal performance and energy consumption of buildings. From that end, the research aims to evaluate the thermal performance of different geometric shapes and orientations of residential buildings. The research adopts the analytical approach through the simulation of different possible scenarios using of building shapes and orientation using comprehensive environmental software “Autodesk ECOTECT”. It aims to achieve the best possible configuration that exhibit best thermal performance for use in residential buildings in the region of Tebessa (Algeria).The results indicate significant thermal effects due to proportions of building’s shape and its orientation. Therefore, this research recommends applying passive solar design strategies, particularly with respect to the geometric shape and orientation recommendations in the first stage of the design process. The proportions of the building must be determined with a complete understanding of their impact on thermal performance and energy consumption.

日射制御と潜熱蓄熱材による住宅用ダイレクトゲイン手法の提案 （第9報）熱負荷削減及び快適性向上効果に係る因子の検討

日射制御と潜熱蓄熱材による住宅用ダイレクトゲイン手法の提案 （第9報）熱負荷削減及び快適性向上効果に係る因子の検討

AN INSTITUTIONAL PERSPECTIVE ON THE ADAPTATION AND MITIGATION OF CLIMATE CHANGE IN THE HOUSING SECTOR IN THE NORTHERN REGION OF GHANA

The study examined adaptation and mitigation of climate change in the housing sector from an institutional perspective in the Northern Region of Ghana. The study employed descriptive research design within the qualitative approach. The data was acquired through in-depth interviews and document study. Officials from the regional Department of Rural Housing (DRU) and Metropolitan, Municipal and District Assemblies were interviewed. The study revealed that there was a high priority on technical training on housing construction, promoting the use of impact-resistant building materials, passive solar design as well as surface and underground tanks as adaptation measures while promoting the use of energy efficient household appliances was the only climate change mitigation measure in the housing sector. The Metropolitan, Municipal and District Assemblies on the other hand did not have specific institutional structures within the assemblies to deal with climate change issues in the housing sector. The study identified an insufficient finances, ineffective fiscal decentralization as well as logistics and equipment as the main challenges faced by the DRU in climate change response in the region. The study recommends that the department should be adequately resourced financially as well as working logistics and equipment to undertake their core functions