Passive Solutions Research Articles

Performance of Solar Control Films on Building Glazing: A Literature Review

Buildings with a high window-to-wall ratio tend to suffer from excessive solar gains/losses that usually result in high energy demand and discomfort for occupants. Solar control films (SCFs) are a passive solution with the potential to increase the performance of new or refurbished glazing they are applied to. This paper presents a comprehensive literature review of the performance of SCFs applied to glazing systems of buildings. Research studies with experimental, analytical and computer simulation approaches were gathered and analyzed, identifying glass and film systems, climatic conditions, energy savings and comfort performance. The research approaches and main findings of existing research studies were compared and discussed. The presence of SCFs significantly reduced indoor solar radiation and illuminance levels, particularly with reflective films applied to south-oriented glazing (northern hemisphere). Glazing systems with SCFs were reported to promote cooling energy savings compared with clear glazing in hot climates. Few studies have explored the visual and thermal comfort performance of SCFs, concluding that these films promote thermal comfort, and reduce excessive illuminance and potential glare. Furthermore, this paper helps to highlight areas of guidance for future studies on the topic.

Life cycle cost analysis of near zero energy buildings benefited from earth-sheltering

Using passive solutions to take advantage of ambient energy sources would be more credible by considering the economic aspects of the project. Compared to aboveground buildings, Earth-Sheltered buildings (ESBs) have better energy efficiency. However, they might not be economically justifiable due to the escalation in construction costs. This paper presents a comprehensive analytical framework to compare the ESB options in the early design stage by the life cycle costs, including the cost/benefits of becoming a Net Zero energy building. An under-construction earth-sheltered hotel has been simulated using DesignBuilder® software to validate the method. Simulations were carried out to estimate the changes in energy consumption and cooling/heating loads for different wall structures, architectural forms, and soil cover depths. To evaluate the sensitivity of the results, Latin hypercube sampling (LHS) simulation was used. The results show that reducing energy consumption by earth sheltering is significant. Also, the Net present value (NPV) is statistically significantly positive, and forms are meaningfully influential. According to the results, the highest NPV is obtained when the depth of the building is seven meters. The uncertainty analysis results indicate that electricity price, interest rate, cooling setpoint, ground reflectance, and equipment consumption play a key role in NPV.

Architectural Comparison of Chosen Passive Building Standards

Abstract The building sector consumes one-third of global final energy and emits nearly 40% of total CO2 emission. To decrease those numbers, it is necessary to design sustainable buildings, which have low heat and cooling demand. The Passive House standard was designed to meet these requirements however, some imperfections were observed. Therefore, a new approach the “be 2226” standard was put forward. This paper presents major architectural differences of those concepts and discusses their advantages and disadvantages. The main purpose is to develop guidelines how to design energy-efficient passive architecture. The Author used own mixed research method that included literature studies, analyses of technical documentation, in situ examinations, own measurements, and infrared tests. The comparison of two passive standards established strong, proven solutions, as well as incompatibilities and flows of each standard. The research main findings are that all buildings should be built in the passive manner and it would be beneficial to implement mixed standard. The main conclusion is that architectural creation has a great impact on passive solutions in buildings.

Defining the cooling and heating solar efficiency of a building component skin: application to a modular living wall

• Ambient wet bulb temperature limits cooling potential of a building component skin. • Daytime sol–air temperature limits heating potential of a building component skin. • Cooling and heating efficiency of the skin of a building component have been defined. • The efficiency of different skin systems are comparable in a unique value. The thermal evaluation of building components composed of a base wall with a solar passive skin solution, such as a vertical/roof greenery system, ventilated façade, reflective painting, etc., is usually performed as a whole. In this research, it has been proven that, independently of the base wall thermal inertia and insulation level, the temperature of the outermost surface layer of any building component during sunny hours is mainly dependent on the ambient air temperature and relative humidity, the incident global solar radiation and the building skin behaviour. The latter assumption has been proven on the south wall of a reference building simulated with TRNSYS. The south wall properties have been varied and the building has been subjected to different climates. The assumption’s validity has been checked for twelve south wall cases: a combination of 2 thermal transmittance, 2 thermal inertia and 3 climates. Each case has been simulated for a whole year. Based on this finding and the local ambient conditions for sunny hours, the hypothetical achievable maximum and minimum temperatures for the outermost surface layer have been defined. Then, based on the outermost surface temperature experimental measurements, the cooling and heating solar efficiencies valid for any skin solution have been defined. Furthermore, the developed methodology has been applied to a vertical living wall tested for a whole year under the accuracy and quality procedure of the PASLINK method. In this way, the cooling and heating solar efficiencies were experimentally determined for this skin solution for both, the hot cold seasons. The study has shown that the cooling efficiency during the hot season is 90.8%. As expected, even during sunny summer hours, the presence of water positively affects the performance of the façade, as it brings the base wall external surface temperature close to the ambient wet bulb temperature, therefore reducing the cooling load of the building. For the cold season, the cooling efficiency was similar, at 90.3%, which means a heating efficiency of 9.7%. Again, even for sunny winter hours, the values of the external surface temperature tend towards the ambient air wet bulb temperature, resulting in an increase in the heating demand. These experimental efficiency values allow the heating or cooling behaviour of different skin solutions to be comparable with a single number that is independent of the base wall composition. In addition, independently of the base wall composition, once the experimental efficiency value of a given skin solution is known, it allows (during sunny hours) the base wall outermost surface temperature to be calculated with precision. The latter makes it possible to increase the accuracy of the estimation of the heating and cooling demands of such methods as the degree-day method.

A three-stage decision-making process for cost-effective passive solutions in office buildings in the hot summer and cold winter zone in China

China, with the largest energy consumption system in the world, faces numerous challenges in achieving the government’s commitment to reach a carbon-peak and carbon–neutral target. As the most common public building type in terms of floor area, office buildings have great potential for energy saving and emissions reduction. To meet this target, building designers target passive solutions that can meet the thermal comfort needs of occupants and also reduce energy consumption. This study aims to develop a decision-making method to select optimal solutions from among tens of thousands of design options considering the factors of energy consumption, comfort, and cost. We developed a novel optimization decision approach with the above-mentioned three objectives. The model consists of three stages: 1) the establishment of the reference building model, 2) sensitivity analysis to identify the main influencing variables and 3) the establishment of the optimization and decision-making model by applying NSGA-II and TOPSIS methods. By applying this three-stage decision-making model, this paper first proposes cost-effective passive design solutions for office buildings throughout the Hot Summer and Cold Winter climate zone. Finally, an office building in Shanghai was chosen as a case study to demonstrate the practical implementation of the proposed solutions through a post-occupancy evaluation with a two-year energy auditing and thermal comfort survey. It is evident that the proposed solutions provide support for the new low energy building design guide for office buildings along with necessary revisions to the existing standards for the Hot Summer and Cold Winter climate zone in China.

Experimental investigation on the effect of Leading Edge Tubercles on the Performance of Marine Propellers in fully wet condition

Leading edge tubercles (LET) is an attractive passive flow control solution that has been proved to enhance the hydrodynamic performance and efficiency of lifting surfaces adopted in many engineering areas. Nonetheless, their industrial application in control and propulsion devices of marine vehicles is still at the beginning. To move further steps ahead, a preliminary experimental campaign for a five bladed Wageningen B-screw propeller modified with three different configurations of leading edge tubercles was carried out in cavitation free conditions. In particular, the propellers were tested in open water conditions in straight and oblique flow at incidences of 10° and 20°, with the aim to study the effects of LET during steady and moderate unsteady conditions. The propellers are tested at two different chord Reynolds numbers in order to investigate their applicability also to small autonomous marine vehicles. The analysis proved that suitable layout of tubercles can enhance the hydrodynamic efficiency in axial symmetric flow while reducing undesired effects caused by operation in off-design.

Fluidization‐based chemical vapour deposition for alumina coating on tubular carbon steel substrates—Modelling and validation

AbstractThe degradation of carbon steels due to corrosion and gaseous permeation phenomena can be significantly reduced by a thin alumina coating. Tubular carbon steel structures, commonly employed in nuclear establishments are particularly vulnerable to chemical degradation on the inner surface due to the flow of corrosive fluids. In the present work, a fluidization‐based chemical vapour deposition process is applied as a one‐step solution for simultaneous chemical passivation of both inner and outer substrate surfaces meanwhile optimizing precursor inventory by utilizing fluidized bed sublimation and induction heating techniques. The process is studied by using a 2D‐1D mathematical model, which has been validated with experimental results for different carbon steel grades. It was observed that there exists an optimum fluidization velocity for a specified initial mass fraction of precursor powder at which mass of alumina deposited per unit mass of precursor sublimated is maximized.

Green glass space based design for the driven of sustainable cities: A case study

• Green glass space was proposed driven by energy efficiency and thermal comfort. • Seasonal operation characteristics and design parameters of GGS were explored. • GGS can decrease heating energy consumption by about 50% compared with N-GGS. • ADPI is above 85% and PD is below 1% at various heights and angles of GGS. • The optimal design parameters of GGS are at a height of 0.9 h and an angle of 90°. Demand for thermal comfort is high in regions characterized by hot summers and cold winters. Active solutions commonly used to improve comfort level in buildings may increase energy consumption, which hinders the sustainable development of cities. It is of great significance to balance the comfort and energy during the building design phase. Passive solutions present the potential in energy saving, such as glass curtain wall. However, it is difficult to ensure thermal stability in building because of the unsteady heat exchange through glass curtain wall, further affecting the balance. In this work, transitional space consisting of glass façade, i.e., green glass space (GGS), between indoor and outdoor environments is proposed to achieve a favorable balance. The impacts of design parameters (i.e., height and angle of green glass space) are investigated on both thermal comfort and energy efficiency, which are carried out in a case study. Numerical simulation is validated by experimental data. Air distribution performance index (ADPI) and percentage of dissatisfied (PD) are used as indicators to evaluate thermal comfort. Energy saving coefficient is put forward as an index for energy efficiency of green glass space. Results showed that (1) green glass space can decrease heating energy consumption by approximately 50% compared with non-green glass spaces, (2) air distribution performance index is above 85% and percentage of dissatisfied is below 1% at various heights and angles, and (3) optimal design parameters of green glass space are achieved at a height of 0.9 H (H is the building height) and an angle of 90° This study can provide an important reference of design strategy for the sustainable development of green building and cities.

Electrochemical thermodynamics of stress corrosion of pipeline steel in active and passive environments studied by scanning Kelvin probe

ABSTRACT Electrochemical corrosion thermodynamics of an X52 pipeline steel under plastic stresses was studied by measurements of corrosion potential and Volta potential with a scanning Kelvin probe in an anaerobic near-neutral pH and an aerobic high pH corrosive environments, where the steel was under active dissolution and passivity, respectively. The stress-corrosion thermodynamics of the stressed steel in both environments was studied by Volta potential measurements. While the corrosion potential shifts negatively due to a stress-enhanced corrosion activity in both solutions, the shift of Volta potential is more indicative of the corrosion thermodynamics under identical stresses. Volta potential measurements provide a more promising method than corrosion potential to indicate the stress corrosion thermodynamics of the steel. The relationships between Volta potential and corrosion potential in both active and passive solutions deviate from linearity in the presence of stress. However, the difference between the two potentials increases linearly with stress .

Development of Bioclimatic Passive Designs for Office Building in Burkina Faso

This article focuses on adopting effective and affordable bioclimatic building design strategies in Ouagadougou, in the Sudano-Sahelian zone of Burkina Faso. A model representing a standard office building and relevant parameters were input in EnergyPlus, and scenarios were analyzed to evaluate the effect of natural ventilation, window shading, dehumidification with night ventilation, and evaporative cooling with night ventilation on thermal comfort and energy consumption. First, the American Society of Heating, Refrigerating, and Air-conditioning Engineers (ASHRAE) Standard 55 adaptive comfort model was used to compare discomfort hours and interior temperatures between a conventional office design and improved models using passive approaches. The simulations further tested the reduction in energy cooling demand and energy consumption. The results demonstrated that natural ventilation was the most effective passive cooling technique, helping to reduce the annual discomfort hours by 40% and the annual energy consumption by 30%. Combining passive strategies is the best scenario, with a year of office occupancy resulting in just 617 h of discomfort, a 42% reduction in the annual energy cooling demand, and a 43% reduction in the annual energy consumption. The simulations demonstrated the effectiveness of affordable passive design solutions applicable even in existing office buildings and their significance for the sustainable development of fast-urbanizing Sub-Saharan countries.

Upcycling of biomass waste into photothermal superhydrophobic coating for efficient anti-icing and deicing

Superhydrophobic surfaces coupling with photothermal effect, as a passive solution independent of external energy input, have shown promising perspectives for anti-icing and deicing. However, most hydrophobic photothermal materials are costly and require complicated fabrication processes, which limit their development in large-scale applications. Here, a facile method is proposed to fabricate superhydrophobic photothermal anti-icing coating using commercially available biochar (BC) and low-cost titanium nitride (TiN) nanoparticles. The coating displays superior photothermal conversion and anti-icing performance, benefiting from the micro-nano hierarchical structure's light trapping effect and high surface roughness. Meanwhile, the coating shows an extra-long anti-icing time of ∼831s for water droplets, which is ∼17 times longer than pure BC coating. The covering frost and ice can be melted into droplets under the illumination of sunlight and roll off rapidly, leaving a dry surface. The superhydrophobic photothermal coating may promote the development of anti-icing and deicing surfaces in outdoor applications.

Energy-Efficiency Passive Strategies for Mediterranean Climate: An Overview

Among all the activities in a society, construction has a key role in environmental, social, and economic pillars. Construction is also responsible for a considerable amount of waste production, energy consumption, pollutant gas emissions, and consumption of nonrenewable natural resources. Regarding energy consumption, a high demand for building operational energy has been observed in the last decades due to the more demanding requirements of the users with a continuous search for better thermal comfort in their homes, namely in developed countries. In Portugal, for instance, more than 20% of the electricity consumed is related to residential buildings, which is based on CO2 emissions and other pollutants that negatively affect the environment. Much of this consumed energy is a result of the HVAC systems installed inside buildings to provide users with thermal comfort. One exciting opportunity to mitigate buildings’ operational energy consumption while contributing to thermal user comfort is the use of passive solutions. Even though several passive options are available and constantly under research, their use is still considered limited. This paper overviews and highlights the potential of energy-efficiency passive strategies, namely for Mediterranean-climate countries, where passive solar technologies can be set as a viable solution, as this climate is mainly known for its solar availability (solar hours and solar irradiance). A comprehensive overview of innovative and traditional housing passive solutions currently available is presented and discusses the main advantages, disadvantages, and concerns contributing to the optimal use of climatic conditions and natural resources in those regions.

Post-Occupancy Evaluation of an educational building: Case study of the ETS-UESC Building

The physical and environmental conditions of educational institutions are determining factors for occupant comfort. The Post-Occupancy Evaluation (POE) presents itself as a methodology for verifying environmental aspects in full use, considering the technical criteria and the users' perception. This article discusses the particularities of the ETS-UESC building, in Brazil, applying POE with an emphasis on the environmental comfort of the classrooms. For this, an exploratory research was carried out where the users' perception of ambience was verified, through the application of targeted forms and on-site measurements of the thermal and lighting conditions using a thermohygrometer and a lux meter, and natural ventilation conditions by design analysis, in the light of current regulations. The opinions were compared with the environmental measurements to identify the limitations of the building and to find the dissonant points. About 85% of users are bothered by the thermal conditions where they are exposed to high daily temperatures, above 30 ºC. In spring and summer, room temperatures are above those recommended by NR 17 standard. The quality of natural lighting is questioned by approximately 80% of users, even having illuminance above the recommended limit of 300 lux in the daytime cycle. How thermal and lighting conditions restrict the use of spaces was proven, making it necessary to discuss active or passive technical solutions to mitigate these problems. Therefore, some factors and technical solutions were pointed out that will assist in the suitability of the project in question.

Experimental Study of the Effect for Water Depth on the Mass Transfer of Passive Solar Still Chemical Solutions

An experimental study on a passive solar distiller in the Tikrit city on (latitude line"34 36onorth, longitude line "45 43o east), and purpose of that study to raise the efficiency andproductivity of the solar distiller. And then design the monoclinic solar distiller and add reflectorplate and a solar concentrate. The Practical tests were conducted at a rate of every half-hourfrom the beginning of February to the beginning of the month of June. The study began bycomparing the solar distiller that contain the concentrates and without contain it. Then study theinfluence of adding coal and chemical solutions, like blue Thymol solution and bluebromophenol solution to see the additions effect on the productivity and efficiency of distiller,and also The study was conducted to see the effect of the water depth on the productivity ofdistiller with take four water depths within the basin are (2,1.5,1,0.5) cm of water. The tests wereconducted in weather conditions close. and the results of the study, That distilled added hisconcentrates improved its productivity by 46% and efficiency increases 43% with non-use ofconcentrates, and coal increased efficiency by 36% and productivity improved up to 38%, theaddition of blue Thymol solution increases the efficiency by 19% and productivity by 16%, aswell as bromophenol solution increase productivity by 23% and improve efficiency by 25%,when comparing the additions found that the best one is coal. Through the study of the depth ofthe water show that increases productivity and efficiency by reducing the depth of the water inthe basin distiller.

Optimizing passive design strategies for energy efficient buildings using hybrid artificial neural network (ANN) and multi-objective evolutionary algorithm through a case study approach

Building energy reduction opportunities and thermal comfort of occupants are two major aspects that could be enhanced through passive design solutions. In tropical weather conditions such as in India, there have been very minimal efforts in developing simulation-based approaches to understand the impacts of common passive design solutions on energy needs and thermal comfort. Therefore, this study focuses on developing an Artificial Neural Network (ANN) and Building Energy Simulation and Optimization (BESO) based framework to improve building energy performance and thermal comfort using passive design solutions in Indian climate condition with mixed-mode operation strategy. The initial part of the study performs building energy simulation through a coupled approach of DesignBuilder and jEPlus to develop a valid ANN surrogate model. Eventually, ANN outputs are integrated with multi-objective evolutionary algorithm (Non-dominated Sorting Genetic Algorithm-II) to find the optimal solutions of predefined passive decision variables of the building for minimizing building energy consumption and maximizing thermal comfort. The optimized results in the study show decrease of 46% of building energy consumption and 7.58% of discomfort hours when the set of passive design solutions are opted. The findings of optimal passive design solutions could be helpful for designers and practitioners in developing energy-efficient buildings.

Multilayer assembly of phase change material and bio-based concrete: A passive envelope to improve the energy and hygrothermal performance of buildings

Phase change materials (PCMs) can improve indoor thermal comfort and reduce energy consumption, while bio-based concrete is an environment-friendly material that enables indoor humidity regulation and heat insulation. However, only a few studies have explored the integrated application of the two materials and comprehensively analyzed the energy and hygrothermal performance. In this study, a passive envelope solution that integrates PCM and hemp concrete is proposed to improve buildings’ energy, thermal, and hygric performances simultaneously. Four integrated scenarios were considered and compared with a baseline scenario (hemp concrete only). The performance of the integrated envelope was studied numerically based on the impact of the PCM’s properties and its location in the envelope. The results highlight the indispensable role moisture transfer plays in determining the indoor hygric environment and heat load, as well as the valuable effect of the integrated envelope on improving both energy and hygrothermal performance. Scenario 4/5 (with PCM closest to the interior) in the summer showed the greatest performance improvement compared to the baseline scenario, with reductions of 8.2%, 46.3%, and 43.7% for heat load, temperature fluctuation, and partial water vapor pressure fluctuation, respectively. The impact of the PCM properties in scenario 4/5 illustrate that the optimization of the integrated envelope can be achieved by increasing the thickness and latent heat of the PCM and identifying its appropriate phase transition range. From a year-round perspective, scenario 4/5 is also notable, as it shows great potential for saving energy and adapting to climate humidity variation while guaranteeing moisture equilibrium within the hemp concrete. The three-year assessment confirmed a lack of condensation and no risk of mold growth for such an integrated envelope, as the relative humidity in key locations remains below 75%.

Heritage conservation as a bridge to sustainability assessing thermal performance and the preservation of identity through heritage conservation in the Mediterranean city of Nablus

Heritage conservation can revive vernacular architectural methods of construction which naturally embody sustainable design concepts. This research investigates and highlights the intrinsic value of heritage conservation in building a sustainable society; from an environmental, economic, and social perspectives. This research is an evaluation of a unique case of heritage conservation in the city of Nablus, Palestine, at both architectural and urban scales. The investigation concluded that traditional passive design solutions have many advantages over modern ones. It was found that the thermal performance of a conserved traditional building was more effective, making it more sustainable than its modern counterpart with the same function. Further, the investigation concluded that heritage conservation is core to protecting identity in its preservation of the past for future generations, especially in an occupied area, such as Nablus. This study aims to highlight the vast scope and application of heritage conservation with regards to innovative and sustainable solutions in a modern urban society.

Open-loop polarization mode dispersion mitigation for fibre-optic time and frequency transfer.

The non-reciprocal and dynamic nature of polarization mode dispersion (PMD) in optical fibers can be a problem for accurate time and frequency transfer. Here, a simple, passive solution is put forward that is based on transmitting optical pulses with alternating orthogonal polarization. The fast and deterministic polarization modulation means that the PMD noise is pushed far away from the frequencies of interest. Furthermore, upon reflection from a Faraday mirror at the receiver, the pulses have a well-defined polarization when they return to the transmitter, which facilitates stable optical phase detection and fibre phase compensation. In an open-loop test setup that uses a mode-locked laser and a simple pulse interleaver, the polarization mode dispersion is shown to be reduced by more than two orders of magnitude.

Assessment of Different Envelope Configurations via Optimization Analysis and Thermal Performance Indicators: A Case Study in a Tropical Climate

Passive solutions for more energy-efficient buildings are critical to improving our odds in the current energy crisis. This work focuses on assessing the thermal performance of different envelope construction layouts in a tropical climate through proposed indicators regarding the thermal mass degree (TMD) and insulation degree (ID). For this, a numerical study was performed for a reference building (RB) in Panama City and validated with the electricity consumption bills. Behavioral and sensitivity analyses were employed to identify critical heat gains and the most important envelope constructions, resulting in the layouts of the roof and external walls. Optimization analyses were performed to find adequate layouts to reduce the discomfort hours. Different roofs, external walls, internal partition layouts, and glazing types were evaluated. Results indicated that the adequate envelope configuration is a roof layout with low TMD and ID, along with wall layouts with high TMD and low ID.

Modelling of occupant behaviour in non-residential mixed-mode buildings: The distinctive features of tropical climates

This paper focuses on the modelling of occupant behaviour in the case of a non-residential mixed-mode building on the tropical island of La Réunion. For such areas and types of buildings, occupants can operate passive solutions to achieve comfort while energy-consuming ones can offer alternatives during the hottest months. Yet, compared to other climatic zones, specific knowledge on occupant comfort and behaviour is limited, making the work of engineers difficult during the design phase. In this work, occupants’ operations on hygrothermal comfort controls, such as windows and fans, were first measured and analysed. Secondly, these behaviours were modelled using two deterministic methods based on machine learning techniques and a probabilistic graphical model. A model was also implemented to estimate the number of people, using the power demand of the electrical outlets. The estimation ability of the behavioural models was evaluated and led to F1 scores greater than 0.7. A two-classifier model was proposed to estimate the level of ceiling fan use. This combined model slightly improves the F1 scores by more that 2%, which demonstrates the necessity of taking into account the links between the different controls.