Passive Building Research Articles

Experimental analysis of building envelope integrating phase change material and cool paint under a real environment in autumn

The application of phase change material (PCM) and cool paint (CP) to building envelope is one of the effective solutions to improve thermal comfort of passive buildings. Therefore, the thermal performance of buildings in Hefei, China in autumn is compared and analyzed by integrating PCM and CP into the building envelope. According to the comprehensive analysis of indoor thermal environment and the ability to maintain indoor thermal comfort, it is concluded that the combined application of PCM and CP is better than the application of PCM or CP alone. And the combination of PCM and CP laid on the south wall and roof respectively is the best. It is more suitable for commercial buildings, which can prolong indoor air temperature (Ti) in the thermal comfort zone for more than 10 h during the day. The combination of PCM and CP laid on the roof can prolong Ti in the thermal comfort zone for more than 8.05 h, which is more suitable for residential buildings. The purpose is to explore the best combination mode of residential and commercial buildings according to the characteristics of temperature change and building types (according to people's main use time) in the real environment.

Integrated Photonic Passive Building Blocks on Silicon-On-Insulator Platform

Integrated photonics on Silicon-On-Insulator (SOI) substrates is a well developed research field that has already significantly impacted various fields, such as quantum computing, micro sensing devices, biosensing, and high-rate communications. Although quite complex circuits can be made with such technology, everything is based on a few ’building blocks’ which are then combined to form more complex circuits. This review article provides a detailed examination of the state of the art of integrated photonic building blocks focusing on passive elements, covering fundamental principles and design methodologies. Key components discussed include waveguides, fiber-to-chip couplers, edges and gratings, phase shifters, splitters and switches (including y-branch, MMI, and directional couplers), as well as subwavelength grating structures and ring resonators. Additionally, this review addresses challenges and future prospects in advancing integrated photonic circuits on SOI platforms, focusing on scalability, power efficiency, and fabrication issues. The objective of this review is to equip researchers and engineers in the field with a comprehensive understanding of the current landscape and future trajectories of integrated photonic components on SOI substrates with a 220 nm thick device layer of intrinsic silicon.

Near-, medium- and long-term impacts of climate change on the thermal energy consumption of buildings in Finland under RCP climate scenarios

The building sector is critical in climate change mitigation by reducing its energy consumption. At the same time, warming climate requires adaptation measures from buildings, making it necessary to study the future thermal energy demand of buildings. This paper studies the impact of climate change on the thermal energy demand of buildings in a heating dominated climate of Finland, under “representative concentration pathway” (RCP) climate scenarios in near- (2030), medium- (2050) and long-term (2080) horizon. Additionally, the impact of the thermal performance level of the buildings is investigated. The thermal energy demand calculation is based on overarching standards from the European “energy performance of buildings” directive. The weather scenarios present both typical and extreme weather years, applied through morphing and future weather data from the Finnish Meteorological Institute. The results show that annual thermal energy demand in Finland in 2080 can decrease up to 74.6kWh/m2. In addition, the decrease in heating demand will be higher than the increase in cooling demand. Cooling can become the dominant peak in long-term evaluations, especially in South Finland (Vantaa) with passive buildings under RCP8.5 climate scenario. Renovation is the most efficient action to decrease energy intensity, the earliest it is done the better.

Passive Buildings—Big Opportunities or Big Risks? Quantitative Risk Assessment for Passive Buildings Projects

Passive Buildings—Big Opportunities or Big Risks? Quantitative Risk Assessment for Passive Buildings Projects

An Innovative Retrofitting Technique of an Industrial Prefabricated Building Without Evacuation

This paper presents a seismic retrofit of an industrial-type precast reinforced concrete building structure using friction dampers. The project consisted of retrofitting two precast reinforced concrete buildings, one of which will be presented in this paper. Precast concrete is one of the industrial structures' most preferred construction methods due to its low cost, fast construction, and availability in rural areas. Unfortunately, most structures constructed before “Specification for Buildings to be Built in Seismic Zones(TBDY 2018)[5]” are not sufficiently engineered and are expected to perform poorly when exposed to a significant seismic event. The general characteristic of precast reinforced concrete buildings built before TBDY 2018 is their relatively high concrete quality (compared to cast-in-place reinforced concrete buildings) and better reinforcement workmanship. But they have some characteristic weaknesses as well. Weak beam-column connections, high drift ratios due to heavy beams, instability problems, and lack of frame behavior can be considered primary weaknesses. General classical retrofitting techniques include increasing beam/column sections or adding new reinforced concrete or steel members to the system or FRP(fiber-reinforced polymer) wrapping. Mostly classical retrofitting needs additional foundations. All these techniques require a long construction period, causing evacuation and stopping building usage. Because stopping the production cost can be tolerated by the owners, a retrofitting approach that can be assembled during the normal function of the industrial structures is required. As a result of this requirement, friction dampers are selected as the supplemental energy dissipation device. ASCE 41-17 [10] is employed for the building's damper design and performance evaluation. Before the damper study, some instability and weak connection problems are solved by traditional strengthening measures. The most effective damper configuration and capacities are selected after an iterative trial-and-error linear study using the simplified methods developed by PROMER. Nonlinear push-over analyses are conducted after linear prestudies. Finally, a nonlinear time-history analysis is performed for confirmation of the results. , It is shown that the proposed retrofit scheme satisfies the desired performance goals for both DBE and MCE events. Overall, it is considered that the proposed retrofit scheme with dampers provides the optimal solution for the Project stakeholders from a performance, design, constructability, and economic point of view. Some application photos will be presented, and methods will be explained in detail in the paper. The friction damper behavior is based on the rotational friction hinge concept. The dampers increase building damping, causing a decrease in earthquake demand. As a result, dampers provide passive energy dissipation and protect buildings from structural and nonstructural damage during moderate and severe earthquakes.

Passive Solar Energy Building

Passive Solar Energy Building

Literature Review on The Whole Life Cycle Assessment of Passive Buildings in The Context of Dual Carbon Emissions

With the increasing global demand for sustainable buildings, passive building design has become an area of concern. The design concept of passive buildings is known for its efficient energy use and excellent indoor environmental quality. However, there is a need to delve deeper in order to fully assess the economics and sustainability of passive buildings. The whole life cycle management of passive buildings is a relatively new management concept, and the evaluation research of the whole life cycle of passive buildings under the dual-carbon target is still limited. This paper reviews the evaluation methods and criteria based on the whole life cycle of passive buildings. The literature review includes research conducted over the past two decades and will focus on evaluation indicators for passive buildings. Many reviews present evaluation indicators for low energy design in the full life cycle evaluation of passive buildings and discuss future design directions. This literature review serves as a preliminary step to guide the evaluation criteria of passive buildings in light of China's two-carbon target, which will help to enrich the evaluation indicators of passive buildings and promote the transition to high-quality development of passive buildings.

Experimental validation of ventilated double-skin façades aided by neural networks and thermal modelling for heating demand reduction

Buildings are a significant contributor to global energy consumption, particularly in cold regions where heating is a primary concern. Double-Skin Façades have emerged as a promising passive building technology by reducing heating demand and enhancing thermal comfort. This study introduces a novel approach using a neural network-aided thermal model to improve the assessment of Double-Skin Façades. Annual real-time data was collected from an existing façade before conducting a sensitivity analysis to identify critical variables impacting heat loss through the façade. These variables were subsequently utilized to develop a heat transfer model for the existing façade. After validation against experimentally collected data, the model was updated for evaluating the proposed Double-Skin Façades. Evaluation under various conditions, including closed, natural ventilation, and mechanical ventilation scenarios, demonstrated the potential of Double-Skin Façades in reducing heat loss in cold regions. The developed heat transfer model showed significant accuracy, with minimal average errors of 0.20 % in winter and 0.32 % in summer. In winter, closed Double-Skin Façades significantly reduced heat loss by up to 24.65 % compared to Single-Skin Façades. In summer, mechanically ventilated Double-Skin Façades reduced heat gain by up to 33.7 % for a cavity airflow of 1.6 m/s.

Enhanced co-design and evaluation of a collective robotic construction system for the assembly of large-scale in-plane timber structures

Collective robotic construction (CRC) is an emerging approach to construction automation based on the collaboration among teams of small mobile robots. This paper enhances an existing modular CRC system, showcasing its capability to assemble full-scale in-plane timber structures. Utilizing strategies of co-design, the robotic actuators were updated to accommodate material tolerance in the passive building material, timber struts, which they use for locomotion and assemble into structures. A custom effector was also developed to establish architecturally relevant, structural connections between struts. The enhancements address two major challenges in CRC system development: material tolerance and connections. To showcase these research findings and compare with other construction automation systems, a reinforced slab structure was assembled. With a building envelop of 0.485 m3, this is one of the largest structures assembled by a CRC system. As such, the work highlights the potential applicability of CRC in real-world architectural projects.

Modelling and onsite testing on dynamic thermal responses of built environment in passive solar rooms on Tibetan plateau

It of great importance in assessing built thermal environment level and evaluating corresponding indoor air conditioning demand for energy conservation in construction sectors. Nevertheless, because of the unique meteorological features in plateau area, classical building performance simulation approach contributes to thermal performance evaluation errors since most design codes or standards relies on low attitude regions. In this paper, a modified and improved dynamic thermal design model is put forward for built environment and energy consumption estimation for passive buildings for plateau buildings. Moreover, the simplified experiment is set up to monitor dynamic thermal responses for modelling building. The testing validation illustrate that the onsite measurement accuracy level is quite acceptable for engineering applications with less than 30% relative change range coefficient. Besides, the experiment data demonstrates that window-to-wall ratios, architectural orientation, thermal insulation coefficients, have substantial impacts for solar heat gains in plateau buildings. The study renders building design guidance for energy conservation in high altitude plateau areas.

Thermal Impact Investigation of Shaded Opaque Walls in Bangkok

The effectiveness of overhang shading devices in mitigating solar radiation on opaque walls is crucial for passive building design in tropical regions. However, opaque walls commonly are side-lined in shading design due to a preoccupation with insulation properties, appearance, and aesthetics. Unprotected walls exposed to solar radiation maximize heat gain, while shaded walls decrease external heat gain and indoor temperature, resulting in improved indoor thermal comfort and well-being. This research employs EnergyPlus and SPSS to investigate the optimal design of overhang shading devices for opaque walls in Bangkok, Thailand. The investigation is divided into two phases: (1) determination of the optimal depth-to-space ratio of overhang devices based on a parametric study of 12 overhang configurations; (2) an evaluation of the ratio in reducing solar radiation. The findings demonstrate a relationship between the device depths and the wall solar radiation and indoor temperature. The optimum depth-to-space ratio is suggested as 1:1.15, which can lower the annual average indoor temperature by 3.53% (1.18°C) compared to the benchmark design. Deeper shading device depths than the optimum depth-to-space ratio can be applied, with a slight improvement in protective performance (and commensurately increased costs). This research underscores the importance of overhang shading devices as a performance-improving strategy for buildings in the tropical climate of Thailand.

Embodied carbon emissions of buildings: Taking a step towards net zero buildings

As global concerns about climate change and environmental sustainability escalate, the construction industry is shifting significantly towards eco-resilient and sustainable building practices. This paper comprehensively explores integrating Building Information Modelling (BIM) with eco-resilient principles to create a framework for designing and constructing sustainable buildings. This research introduced a practical approach for evaluating the embodied carbon from building construction, drawing insights from a residential building in Yangon City, Myanmar. The method developed in this study aims to assess the carbon footprints associated with distinct stages of the construction process, including raw material production and material transportation. Additionally, the proposed method compares the material embodied carbon, transportation embodied carbon, and total cost in the residential building, considering two cases of traditional and low-carbon materials. The results indicate that material embodied carbon contributes merely 84% to the overall, while material transportation makes up the remaining 16% for both cases. Utilising low-carbon materials yields remarkable reductions, with a 40% decrease in material embodied carbon and a 39% decrease in transportation carbon footprint compared to conventional materials. However, adopting low-carbon materials incurs a modest increase of approximately 6.7% in total cost. This study underscores the imperative of integrating low-carbon materials into the design of future passive buildings, advancing the pursuit of a net-zero strategy. This research underlines the potential for BIM-driven eco-resilient practices in mitigating carbon emissions and the need for continued innovation and collaboration in sustainable building design and construction.

Towards a net-zero-energy building with smart control of Trombe walls, underground air ducts, and optimal microgrid composed of renewable energy systems

In recent years, permanent outages and lack of access to electricity have been significant problems in most cities of Iran. The increasing growth of fossil fuel consumption made it necessary to change the design of buildings. Designing a net-zero energy building (with natural ventilation and renewable energy systems) is a solution for reducing fossil fuels. In this paper, dynamic energy modeling of the building for the smart operation of the trapezoidal Trombe wall and underground air ducts is performed. In the first step, the Trombe Zones are considered for heating. Then the combination of the Trombe zones with underground air ducts for cooling is simulated. Then the system combination with a solar hot water system to supply hot water energy is evaluated. Finally, the economic analysis of the optimal hybrid system (with a photovoltaic system, wind turbine, battery, and inverter) for supplying the electricity of the building equipped with both passive energy strategies was evaluated by Homer software. The results show that by integrating the Trombe wall, the heating load is reduced by 44 %, and by integrating a coupled geothermal cooling system with the air duct and the Trombe wall, the cooling load is reduced by 39%. Also, the net present cost over the 25-year life of the optimized renewable system is reduced by about 12.5% due to both passive strategies. The average daily electricity energy demand of the base building is equal to 86.37 kWh and for the passive building, it is equal to 67.49 kWh.

Numerical simulation study on the effect of internal heat source on pumping ventilation

Natural ventilation is a passive building technology that can reduce energy consumption for mechanical cooling of the indoor environment. Natural ventilation technology has received renewed attention from researchers. Theoretical studies on natural ventilation have evolved from a steady state to a non-steady state. Pumping ventilation is distinct from other ways of natural ventilation in that its flow direction alternatingly changes from the indoor to the outdoor. However, all published studies did not consider the influence of internal heat sources in pumping ventilation, and there are few discussions about the fluid periodic variation in wind-thermal coupling studies. Based on a previous study, the numerical simulation of single-sided pumping ventilation with two openings in the same wall driven by wind and thermal pressure is conducted in the paper. The influence of heat source intensity and the height of the location of the heat source are analyzed. The applicability of different ventilation rate calculation formulas is discussed. The results show that the indoor airflow oscillation frequency decreases in the effect of wind and thermal pressure, compared to driven by air pressure alone. However, changing the height location and intensity of the heat source does not affect the frequency characteristics in these cases.

Modeling and optimization of a passive building HVAC system based on improved PSO and H-J Algorithm

Passive buildings employ the principles of active optimization and passive priority to demonstrate their energy-saving, comfortable, and cost-effective qualities, thereby addressing energy consumption in an efficient manner. However, it cannot be ignored that the Heating Ventilation Air Conditioning (HVAC) system is still the largest energy consumer, especially when it is necessary to maintain the comfort of the indoor environment. Consequently, the control and optimization of the HVAC system is a research hotspot and a challenge in the field of building energy conservation, as it is the key to achieving ultra-low energy consumption operation in passive buildings while ensuring the thermal comfort of the indoor environment. This paper presents a comprehensive modeling, control, and optimization framework for the efficient operation of HVAC systems in a passive building located in Jinan, China. Firstly, the HVAC system is modeled using the transient system simulation tool (TRNSYS), GenOpt, Java, and other software. Secondly, the HVAC system’s year-round operation is simulated using specific configurations. In order to enhance the energy-saving effect, a strategy of increasing heat storage and return air ducts was proposed, and a significant energy-saving effect (approximately 17.31%) was realized. Lastly, the data communication interface with GenOpt is established utilizing the TRNOPT module, a method for actively optimizing the refrigerant temperature is proposed, and recalculation and optimization are carried out utilizing the swarm intelligence algorithm and the pattern search algorithm (Hooker-Jeeves algorithm, H-J algorithm). The final optimization results demonstrate a 19% reduction in energy consumption relative to the baseline heat recovery model, validating the applicability of the optimization method under this strategy. The control and optimization method of the HVAC system proposed in this paper can further exploit the energy-saving potential of the passive building HVAC system and will contribute to the advancement of building energy conservation.

Application of Novel Phase Change Material Constructive Solution for Thermal Regulation of Passive Solar Buildings

A comprehensive investigation regarding the hygrothermal behavior of a constructive solution containing phase change materials (PCMs) was performed on a full-scale test cell, divided into two similar compartments. This involved hygrothermal monitoring (indoor air temperature) of the two compartments, in which one had PCM incorporated into the floor mortar. The main goal of this research was to investigate the potential of this kind of solution for overheating mitigation. The numerical study was conducted using EnergyPlus® software (version 9.0), exploring different natural ventilation flow rates to gauge the novel solution’s potential to reduce overheating rates. The results from the monitoring studies revealed prolonged periods of thermal discomfort in both test cells, particularly overheating. However, it was proven that the PCM application in one of the test cells led to a reduction of almost 10 °C in the maximum peak of air temperature. In the simulation analysis, the increase in the ventilation rate led to a linear decrease in the overheating hours of up to one renovation per hour, and then the reductions were attenuated.

Enhancing indoor comfort and building energy efficiency with cross-laminated timber (CLT) in hygrothermal environments

The hygrothermal behavior of a building is important because it directly influences indoor comfort levels and energy consumption. Hence, effective strategies must be implemented to minimize energy consumption while optimizing indoor conditions. This study analyzed indoor hygrothermal environments and energy consumption in scenarios related to passive and active building elements, such as exterior walls and indoor control temperature. A simulation considering hygrothermal behavior in walls and spaces was utilized, and the accuracy of the model was validated via an on-site test. Here, cross-laminated timber (CLT) walls, which have been proposed for their energy-saving potential, were substituted for conventional concrete walls. The application of CLT walls enhances indoor comfort better than concrete walls. Despite using the same CLT material, different wall layer compositions lead to internal moisture accumulation. Hence, it was determined that appropriate wall layer compositions should be selected based on regional climate conditions. Furthermore, although indoor comfort was ensured by varying indoor control temperatures, the energy consumption of the heating and cooling systems increased by up to 81 %. Despite the application of passive elements, an indoor heating temperature of 24 °C achieves an optimal balance between comfort and energy consumption. This temperature ensured a satisfactory indoor comfort level and facilitated a manageable increase in energy consumption. In summary, this study provides nuanced insights into the hygrothermal dynamics of buildings, emphasizing the demand for strategic materials, considering regional climates, and carefully managing indoor temperatures to strike an effective balance between comfort and energy efficiency.

The road to nearly zero energy buildings. Case of study: Spain. Comparison between CTE HE 2006 and 2013 in a simulated model

Achieving Nearly Zero-Energy Buildings (NZEBs) is a main goal for the European Union, in order to reduce energy consumption in the building sector. NZEB means a building that has a very high energy performance. Its energy requirements should be covered by renewable sources, produced on-site or nearby [1]. It could be possible if building were turned into a “small power generating station”, or reducing consumption with passive building proposals. However, we think that it is worth looking for a balance between energy consumption and generation for every building, following this simple equation: Consumption = demand – generation The European regulations have already begun to indicate deadlines to implement NZEB requirements in buildings. Therefore, Spanish legislation related to energy efficiency and renewable energy generation in buildings has been recently updated, CTE HE [2]. This paper provides a comparative analysis for the new requirements (2013 CTE DB HE compared with previous 2006 regulation, revised in 2009). This study was performed by using a computer building model, including its geometry, building materials, usage profiles and installations. Thus, we could compare the characteristics of the different regulations, and we could evaluate the progress toward the NZEB concept.

A holistic two-stage decision-making methodology for passive and active building design strategies under uncertainty

In the last decade, many studies focused on finding optimal design solutions considering trade-offs between different aspects of building design. Accordingly, multi-objective optimization (MOO) approaches have been increasingly applied in the building industry. However, certain aspects must be deepened to ensure a more effective decision-making process in the early planning phase. On the one hand, uncertainties should be considered before making decisions to ensure the robustness of the optimal solutions; on the other hand, decisions are made at different times in building planning, and the sequential order of making decisions should be modeled. This paper presents a holistic two-stage multi-objective stochastic optimization (MOSO)-II framework to minimize the environmental impact of global warming potential (GWP) and cost throughout the entire life cycle of a building (phases of A1-A3, B4, B6 and C3-C4), considering passive and active design strategies in two consecutive stages, under uncertainty. Herein, individual/use and political/market uncertainties are considered. As a proof of concept, the proposed framework is applied in a case study for a generic zone in a multi-family terraced residential building type with solid brick construction. The advantages of the proposed framework are validated by comparing it with alternative single-stage MOSO frameworks. Results show that the proposed two-stage MOSO-II framework can deliver a smaller range of solutions with a better performance in terms of lower GWP and cost. It indicates that the proposed framework can effectively assist planners in decision-making by reducing the effort in choosing the proper solution. Secondly, the results also emphasize the importance of passive design strategies in sustainable building planning. In addition, the energy mix structure and cost of energy sources should be carefully adjusted in the future to promote a more ecologically sustainable building design.

Passive Building Energy Saving: Building Envelope Retrofitting Measures to Reduce Cooling Requirements for a Residential Building in an Arid Climate

In arid climates, a significant portion of the urban peak energy demand is dedicated to cooling and air-conditioning during the summer. The rapid urbanization rates in developing countries, particularly in the Gulf Cooperation Council (GCC), have intensified the pressure on energy resources to meet the indoor comfort needs of residents. As a result, there has been a substantial increase in energy demand, with a 2.3% rise recorded in 2018. Electricity consumption in residential buildings accounted for over 48.6% of the total electricity consumption. The choice of building fabrics used in a residential building can significantly impact the building’s passive performance and carbon footprint. This study aimed to enhance our understanding of how specific fabric details influence cooling energy usage in arid climates. To achieve this, a validation simulation model was initially created as a base case for a residential housing typology in Al Ain, UAE. This was followed by a parametric energy evaluation of various building envelope features. The evaluation was based on the reduction of yearly cooling load energy. The simulation results indicate that incorporating 50 mm of expanded polystyrene insulation into the outside walls significantly reduced energy consumption for cooling requirements in the arid UAE climate. Furthermore, no substantial difference was observed in the various roofing choices, including cool and green roofs, gravels, and sand roofs. Additionally, we concluded that the total solar energy transmittance (g-value) of windows played a more significant role than thermal transmittance (U-value) in reducing solar heat gain within the spaces. These findings should guide strategic decisions on building envelope upgrading for sustainable societies.