Energy Conscious Building Research Articles

Building glass retrofitting strategies in hot and dry climates: Cost savings on cooling, diurnal lighting, color rendering, and payback timeframes

Building glazing is a weak thermal envelope that admits too much solar heat, resulting in increased air conditioning expenditures. An optimal glazing system must be chosen to promote the thermal and visual comfort of building interiors. The current study examines how different glass retrofits affect the air-conditioning cost savings of an office building in a hot and dry region of India. To assess the thermal performance of the building, the apertures of the office building were retrofitted with brick glass, stained, tinted, reflective, laminated, polymer dispersed liquid crystal film glazing, and double-glazed window systems. The spectral characteristics of the studied retrofit glazing systems were measured experimentally, and a mathematical model was developed to estimate the heat gain, cooling cost demand, and energy savings for air-conditioning. The polymer dispersed liquid crystal film glazing retrofit provided the highest average air-conditioning cost savings (5.11 $/m2), while the air-filled double-glazing configuration showed the lowest (0.30 $/m2), relative to the original glazing installation among the other retrofits tested. The examined retrofit glazing systems have a colour rendering index of more than 80, indicating appropriate lighting quality. The findings of this study are critical in determining the most energy-efficient retrofit glazing solutions for energy-conscious building design.

A novel glazing system filled with hydrogel granules: energy saving, diurnal illumination, color rendering, and co2 emission mitigation prospective

ABSTRACT Building glazing systems have a significant impact on air-conditioning loads and diurnal illumination in buildings. Incorporating thermal-insulating materials in the interspace of double-glazing is an ideal energy-efficient choice to insulate glazing for reduced air-conditioning costs with comfortable daylight factors. This paper evaluates the solar-optical, color rendering properties, thermal indices, and cost-savings potential of novel glazing systems, where the air-space of double-glazing is filled with different colored hydrogel granules (hydrogel glazing). Thermo-economic analysis was carried out with a numerical model for India’s three distinct climatic regions (Warm, Hot, and Temperate). Proposed hydrogel glazing showed a substantial heat gain/loss reduction, resulting in enhanced air-conditioning cost savings. The double glazing with orange hydrogels granules (DGOH) showed a reduction of 31.67% in summer solar heat gains for the temperate climate. The analysis had concluded net annual cost savings of 6.99 $/m2 for DGOH glazing with a payback period of 0.40 years for the temperate climate. Warm and hot climates also reported identical heat gain reductions and annual savings ($/m2). Carbon emission mitigations of building with hydrogel glazing were estimated with the help of yearly carbon emission factors. The simulated average daylight factors of model buildings with hydrogel glazing were well above the recommended levels in compliance with building codes. The assessed color rendering metrics of hydrogel glazings were satisfactory for visual acceptability in building interiors. The results of this work help engineers and architects to decide on energy-efficient glazing systems for energy-conscious buildings.

Building envelope trade-off method integrated with BIM-based framework for energy-efficient building envelope

ABSTRACT In recent years, the demand for energy-efficient buildings and green buildings has increased significantly in India. However, this surge has few hindrances, i.e. the absence of a centralised green material library, alterations in the later stage of design for certification and few energy certified buildings. This paper proposed a BIM-based workflow that mainstreams this surge of energy-conscious buildings’ envelope using Building Envelope Trade-off Method (BETM) in the early design phase. BETM facilitates energy-efficient envelope through simpler calculations based on material thermal properties, orientation and surface area. A BIM library is modelled for commonly used materials and passive features. The developed workflow is demonstrated on a selected building complex, and its effectiveness is tested with a parametric simulation of 216 envelope combinations of different alternative envelope materials, orientations, and passive facade features. This result shows a similar envelope performance factor ratio for the considered orientations, whereas 0.35% and 12.49% reduction is observed in the corresponding peak cooling total load (PCTL) compared to the as-built case. The PCTL provides the necessary insight into building energy analysis considering its surrounding features. The developed workflow will ensure a better performing building envelope according to the Energy Conservation Building Code.

The Criteria of Passive and Low Energy in Building Design for Tropical Climate in Thailand

Due to high level of energy consumption and increasing environmental concerns, energy efficiency has become a critical issue today. Buildings alone account for around 30 percent of the world’s total energy consumption. The way buildings are designed and constructed today will not only have an impact on their operating costs, but it will also affect the world’s energy consumption patterns and environmental conditions for many years to come. For much of the building industry in Thailand, the designed-in approach to energy-efficient design does not reflect current market practice. In reality, without passive design, numerous opportunitiesfor designing better performance buildings can be wasted.The integration of passive design is thus a key to energy conscious buildings. The integration of passive design approach optimizes the interactions between the natural environment, building envelope and systems as an integrated system. This research examines which components work best altogether to save energy and reduce environmental impacts on buildings in the tropical region. The outcomes of this research aim to set up the criteria of passive and low energy in building design for the tropical climate in Thailand. These fundamental differences will lead to a very different architectural and constructional design. It is imperative that the decision be made at an early stage in the design and there are tremendous opportunities to use smart, energy efficient designs to reduce the energy footprint of the built environment for decades to come.

Revisiting the role of professionals in designing buildings with low embodied and operational energy

Purpose Many studies have focused on embodied energy (EE) and operational energy (OE), but a shortage of studies on decision making, which involves several decision makers whose decisions can affect the energy performance of buildings, is evident. From the stages of the project life cycle, the design stage is identified as the ideal stage for integrating energy efficiency into buildings. Therefore, the purpose of this paper is to revisit the role of professionals in designing energy-conscious buildings with low EE and OE. Design/methodology/approach This study administered a qualitative approach. Data were collected through semi-structured interviews only with 12 experts, due to the lack of expertise in the subject matter. The data were analyzed using manual content analysis. Findings The outcomes revealed the necessity to revisit the role of construction professionals in terms of adopting energy-efficient building design concepts from the project outset. The roles of the key professional groups (i.e. architects, structural engineers, services engineers and quantity surveyors) were identified through this research. Common issues in designing energy-efficient buildings and the means of addressing such problems were outlined. Originality/value This study contributes to the knowledge by revisiting the roles of construction professionals and proposing how they could leverage their strengths to play the important role and contribute collectively to design buildings with both low OE and EE.

Bioclimatic analysis of Iranian climate for energy conservation in architecture

In order to design energy conscious buildings we need to know the climate of each country. In this study a bioclimatic analysis of Iranian climate had been done. Iran is a large country with different kinds of climate and basically includes four different climatic regions such as temperate-humid in southern shores of Caspian Sea, hot-humid in northern shores of Persian Gulf and Oman Sea, very cold and long winter sessions and very hot and dry summers at the central part of Iran. At first the authors surveyed the existing climatic classifications of Iran. Afterwards by retrieving the climatic data from sixty eight Iranian Meteorological stations, and using the new bioclimatic chart a new climatic classification for architectural purposes has been made. As a result of this, five climates were identified for Iran. In order to prove that this new classification is valid, the traditional architecture of these climatic regions was compared. It was found that the traditional buildings have different features in these five regions. Key words: Climate, climatic classification, vernacular architecture of Iran, bioclimatic analysis.

Assessing effectiveness of utilization of passive design parameters on active energy consumption in public buildings in warm-humid climate

Energy requirement in buildings for physiological comfort can be in form of active or passive energy. When the buildings are not energy conscious and passive energy is not well utilized to achieve the desired comfort level, the use of active energy becomes necessary. The mean minimum satisfaction rating of 1.13 which was significantly correlated at 0.01 level, and mean maximum satisfaction rating of 3.34 which was significantly correlated at 0.05 level were achieved. Various strategies for energy conscious building design were highlighted. The study revealed in the regression models that the contribution and effectiveness of the sets of explanatory variables varied. The regression equations for each of the subsectors of the public buildings was with 0.610 ≥ R2 ≥ 0.099, 0.520 ≥ AR2 ≥ 0.033 and 0.227 ≥ significant level ≥ 0.000. The effectiveness/contribution of utilization of most effective independent variables of climate responsive design (CRD) parameters on active energy consumption (Ec) are 0.327(32.7%) ≥ SR2 ≥ 0.000(0.0%). Key words: Buildings, physiological comfort, passive energy, active energy, energy conscious building design, climate responsive design (CRD) parameters.

The influence of the external walls thermal inertia on the energy performance of well insulated buildings

Energy conscious building design consists in controlling the thermophysical characteristics of the building envelope such as, firstly, thermal transmittance ( U-value). However, besides the U-value, the envelope thermal inertia should also be considered. The literature studies report very different estimations regarding the energy saving potential associated with the use of an adequate inertia, ranging from a few percentages to more than 80%. Therefore, this study aims at assessing the parameters enhancing or damping the role of thermal inertia, providing a variety of results. For this purpose several external wall systems with the same U-value but different dynamic properties were investigated to calculate the associated achievable energy savings. A parametric analysis was performed in progressive steps, by running the models of a virtual Test Cell and of a sample building. Both design parameters (heat transfer surface, solar control) and operational ones (ventilation rates, HVAC functional regime) were varied. It was found that the highest energy performance wall system has a proper combination of the dynamic thermal transmittance and thermal admittance values, although not necessarily the best ones. Moreover, it was shown that thermal inertia effects are enhanced if it is coupled with other energy saving measures and an efficient building use.

Concert and conference center — Pécs; Energetic and ecological concept

In general, people do not connect a concert and conference center with a structure that incorporates ecological energy use and material saving construction methods [1]. A sustainable energy-conscious building has been developed, through a new and unique interpretation of functions and space, organically integrating the individual buildings into the energy concept and by utilizing the laws of the local environmental energy as well as specific laws of physics and acoustics.

Energy conservation regulations: Impacts on design and procurement of low energy buildings

To reduce the substantial contribution of the built environment to energy consumption and carbon dioxide emissions, the new ‘Part L: Conservation of Fuel and Power’ of the Building Regulations for England and Wales came into force in April, 2006. As a result, the design of all new-build and refurbished buildings must comply with ‘Target Carbon Emissions Rates’. Apart from the purely practical implications of compliance, the new Part L has prompted interesting questions concerning procurement and the impact on design and construction teams. The so-called ‘traditional method’ of procurement presupposes that designs are, in theory, completed before contractor involvement. In contrast, Design-and-Build (of which there has been a marked increase) relies upon a certain amount of concurrency in design, procurement and construction. In the light of the new Part L requirements, this presents a risk, particularly in the case of environmentally sensitive buildings, where the necessary design iterations are at odds with the contractor's time and cost incentives. These concerns have prompted the current investigation. Although the challenges relate to buildings as a whole, particular attention was paid to façades, as they represent an especially sensitive element. Data collection was by semi-structured interviews from a sample representing a selection of large construction companies, architectural practices and building performance consultants. The research framework was published in the proceedings of the 2007 Conference of the Association of Researchers in Construction Management where it was selected for discussion in an industry-wide forum, and the current paper reflects this response and develops the topic further. [Hamza N. Greenwood D. The impact of procurement routes on delivering energy conscious buildings. In: Boyd D. editor. Proceedings of Association of Researchers in Construction Management (ARCOM), Vol. 2; September 3–5 2007. p. 723–732, Belfast, Northern Ireland.] [1].

Improving energy performance of school buildings while ensuring indoor air quality ventilation

Energy conscious design of school buildings, as well as deemed-to-satisfy provisions in a Performance Based Energy Code, should address the problem known as the energy efficiency—thermal comfort—indoor air quality dilemma (EE-TC-IAQ Dilemma). In warm and moderate climates, the large internal heat sources usually found in school buildings prevent achieving thermal comfort without active cooling in summer, but are not sufficient to eliminate the need for heating in winter. Commonly used air-conditioners do not improve air quality, while natural ventilation induces uncontrolled energy losses. In this study, a step by step process was used for the development of deemed-to-satisfy design solutions, which cope with the EE-TC-IAQ Dilemma, for a performance based code. A distinction is made between improving building design variables and improving ventilation schemes. Results indicate that implementation of improved ventilation schemes in an otherwise well designed energy-conscious building result in savings of 28–30% and 17–18% for northern and southern classroom orientations, respectively.

IDEA: Interactive Database for Energy‐efficient Architecture

The project IDEA – Interactive Database for Energy‐efficient Architecture – is a multinational collaborative project to build a European knowledge base on advanced energy conscious building design. At the core of this project are two earlier multimedia developments, the Swiss program DIAS and the German adaptation NESA which present the principles and applications of solar architecture in the respective national contexts. IDEA aims to improve know‐how of European professionals and exchange of information between them. The database includes information on exemplary buildings, their technical concepts and on other specific conditions. IDEA presents the existing state of the art in the field of energy‐efficient architecture by means of a multimedia database of built examples, an encyclopedia of design concepts and a set of interactive design support tools. The built examples have been selected from around Europe. IDEA assembles technical information on materials and energy‐related standards and regulations and provides climatic data from all relevant European regions.

Integrating energy consciousness in the design process

The design process for an intelligent, energy conscious building which was built, along with the design tools that were applied, is presented. The building, situated in the hot–humid climate of Rehovot, Israel, houses the laboratories and offices of the Weizmann Institute's Environmental Science and Energy Research Department. Alternative bio-climatic design options were proposed and evaluated throughout the detailed design stage. A building energy performance index (BEPI) was established for each alternative. This index reflects the total amount of energy consumption for heating, cooling, ventilating and lighting used per square meter of floor area. Thermal modeling for the different design alternatives were carried out by means of an hourly dynamic simulation model. The model solves simultaneously the heat transfer equations through all exterior walls, taking into account the thermal mass of each external wall as well as internal partitions. The model was extended to include hourly calculations of daylighting and geometrical shading coefficient of the windows, as well as automated and `smart' control strategies.

Multivariate optimization of design trade-offs for solar low energy buildings

The large number of different design options available for energy conscious building design calls for careful quantitative assessments to find the optimum technology mix for each project. Here, a numerical multivariate optimization procedure is introduced, to draft the optimum building design variables at an early design stage. The approach is based on integrating a non-linear optimization scheme with building modeling, whereby the basic physical, technical and economic interactions between the building design options and energy flows are accounted for. The optimization tool developed then finds the economic optimum, given the project-specific boundary conditions and the energy consumption target. The applicability of the approach is demonstrated through a set of case studies.

Computer aided energy conscious building design

The design process for an energy conscious building, which was built, along with the computer aided design tools that were applied, is presented. The building, situated in the hot-humid climate of Rehovot - Israel, houses the laboratories and offices of the Weizmann Institute's Environmental Science and Energy Research Department. Alternative bio-climatic design options were proposed and evaluated throughout the detailed design stage. A building energy performance index (BEPI) was established for each alternative. This index reflects the total amount of energy consumption for heating, cooling, ventilating and lighting used, per square meter of floor area. Thermal modeling for the different design alternatives were carried out by means of an hourly dynamic simulation model ENERGY. The design strategies were determined by the model PASYS, the shading devices were designed and evaluated using SUNSHADES and SHADING design tools. The building is monitored for the last whole year, and the measured values are close to the predictions.

Moving towards municipal energy planning — The case of Palermo: The importance of non-technical issues

Since the end of 1993, when a new administration took the lead of the city of Palermo, the energy and environmental issues started to rank quite high in the priority list. Several initiatives are being implemented, such as the municipal energy plan, the development of energy conscious building regulations, the diffusion campaign for solar water heaters, the introduction of (indirectly) solar powered electric cars, the strong push in the participation to E.U. programs dealing with energy and the creation of a development agency for renewable energy and ecologically viable water use. These and other successful initiatives are described, as well as the ones that failed and the reasons for successes and failures are discussed.

Off and on reflection

Smart materials, which can change their physical properties, enable a building to adjust its environment to the prevailing conditions. A new addition to their number is the switchable window -- a sandwich of glass, thin metal-hydride films and some medium for delivering hydrogen gas, which can be reversibly converted from reflecting to transparent states. When the technology has improved to allow electronic switching, instead of requiring direct pumping of gas, such switchable windows might be used in energy-conscious building design -- and for the lazy, they would make a good alternative to curtains.

Sol Power: The Evolution of Solar Architecture

This is an examination of the importance the sun has played since the dawn of civilization to the architecture of the 21st century. Designed as a progression of photographic images, the book begins by briefly surveying the origins of all earthly sources of power, showing them, in all forms, to be derived from the sun. Through photosynthesis the sun gives life to trees; trees form the fossil fuels, coal and oil. The sun is essential in the formation of wind, rain and tides, all of which can be converted into usable energy. The book shows how, from the very earliest forms of constructed dwellings, buildings have been designed to make maximum use of the power of the sun: houses designed to enjoy the heat of the day and churches oriented to show the morning light through stained glass windows. The book demonstrates how some architecture began to lose sight of this basic principle during the 20th century, citing the example of Le Corbusier's glass building in Paris that was so hot in summer and so cold in winter that he had to redesign and rebuild the complete facade. It illustrates some of the most famous examples of solar buildings, including the former Crystal Palace in London and the modern Commerzbank tower block in Frankfurt. The text confronts the issues of current wastage of the world's resources caused by poor, uninformed design, and sets out positive ways that modern solar-oriented architecture can lead to energy-conscious buildings. It encourages an awareness of all the earth's limited resources in buildings of the future. The book is published to coincide with the fourth European Conference on Solar Energy in Architecture and Urban Planning, held at the Haus der Kulturen der Welt in Berlin, 1996.

GENWIN: A generative computer tool for window design in energy-conscious architecture

The use of computers as aids in energy-conscious building design has hitherto been confined primarily to evaluative tasks. These are no doubt important, but they do not fully exploit the tremendous potential of computer technology. Generative tools are a move towards using the computer as an ‘active’ complement to the design process rather than merely a ‘passive’ tool. Such a generative tool for window design, named GENWIN, was developed. This paper explains the theory and principles underlying this model, and concludes by illustrating the output derived by running GENWIN for a test case.

An integrated knowledge-based and procedural system for the design of energy conscious buildings

The paper describes a methodology for supporting computationally all phases of an energy-conscious design and evaluation process, by combining procedural simulation and knowledge-based heuristic methods in one integrated system. The methodology is based on partitioning the design process into discrete phases and identifying the energy-conscious informational characteristics of each phase. These informational characteristics are expressed in the form of design variables (parameters) and the relationships between them. The methodology allows for testing the applicability of heuristics rules in non-standard cases, using context-sensitive application of default values and judicious selection of rules of thumb, thereby improving the overall predictive powers of the evaluation. The methodology is demonstrated through developing a KB-CAAD system for the schematic-conceptual design phase of solar and low energy buildings. The system is based on the integration of a knowledge-based model and a simulation model with a commercially available CAAD system for building representation. The knowledge base contains heuristic rules for the design of passive solar buildings. Whenever possible, the knowledge-base guides the designer through the decision making process. However, if the rules of thumb are not acceptable for the particular design problem, the system guides the architect by means of the procedural simulation model. A case study demonstrates how the system leads to the design of better energy conscious buildings, while taking less time and effort to introduce the geometrical data that is needed for the representation of a regular, non-solar building.