THE LEED-COMMERCIAL INTERIORS (V4) PROJECTS IN CALIFORNIA

ABSTRACT This study analyzed the Leadership in Energy and Environmental Design for Commercial Interior Certified, Silver, and Gold projects version 4.0 (LEED-CIv4) in California for the period 2015‒2020. Nonparametric tests were used to assess category and credit achievement, i.e., the difference between possible and achieved points and the correlation between associated credits. The results show that most of the credits in the location and transportation category and the indoor environmental quality categories had a high level of achievement, a few credits in the energy and atmosphere and materials and resources categories had a high level of achievement, and all of the credits in the water efficiency category had a low level of achievement. Some associated credits, such as surrounding density and quality transit, had a high level of achievement and a positive correlation, whereas other associated credits, such as life-cycle impact reduction and environmental product declarations, had a low level of achievement and a positive correlation. If LEED-CIv4 credits meet the requirements of the California Green Building Standards Code 2016 (CGBSC 2016), then these credits typically have a medium/high level of achievement. If LEED-CIv4 credits exceed the requirements of CGBSC 2016, then these credits have a low level of achievement. Therefore, to improve the next version of LEED-CI, it is necessary to improve the local green codes.

RESALE OF GREEN HOUSING COMPENSATES FOR ITS PREMIUM PRICING: AN EMPIRICAL STUDY OF CHINA

ABSTRACT Green housing reduces resource consumption and protects the ecological environment. Sustainable buildings and construction have gained increasing attention in the last decade. Many empirical studies have confirmed that green housing imposes a price premium at the presale stage. The high price could be a concern that prevents homebuyers from purchasing green buildings. However, there is a lack of empirical evidence on whether the premium pricing could be compensated for by the resale price. To address this gap, this study establishes a hedonic regression model to estimate the price premium of green housing at the resale stage. The results show that green housing certified with the Chinese Green Building Label (CGBL) offers a 6% price premium compared with non-green housing at the resale stage. The results also show that green housing with a higher level of green certification, e.g., the 3-star CGBL, provides a greater price premium at resale. The findings indicate that home-buyers can obtain financial compensation for the high cost when purchasing a green home. Our findings also indicate that the price premium for reselling a green home is not always enough to compensate for the purchase cost in different cities. Policy recommendations for government promotion of green housing are also discussed.

ENHANCING THERMAL COMFORT OF RESIDENTIAL BUILDINGS THROUGH A DUAL FUNCTIONAL PASSIVE SYSTEM (SOLAR-WALL)

ABSTRACT Thermal comfort has a great impact on occupants’ productivity and general well-being. Since people spend 80–90% of their time indoors, developing the tools and methods that enhance the thermal comfort for building are worth investigating. Previous studies have proved that using passive systems like Trombe walls and solar chimneys significantly enhanced thermal comfort in inside spaces despite that each system has a specific purpose within a specific climate condition. Hence, the main purpose of this study is to design and configure a new, dual functional passive system, called a solar wall. The new system combines the Trombe wall and solar chimney, and it can cool or heat based on building needs. Simulation software, DesignBuilder, has been used to configure the Solar Wall, and study its impact on indoor operative temperature for the base case. Using the new system, the simulation results were compared with those obtained in the base case and analyzed to determine the most efficient system design parameters and implementation method. The case that gave the best results for solar wall configuration was triple glazed glass and 0.1 cm copper as an absorber (case 11). The results show that using four units (case D) achieves longer thermal comfort levels: 15 to 24 thermal hours during winter (compared to five hours maximum) and 10 to 19 comfort hours in summer (compared to zero).

ENVIRONMENTAL BENEFIT OF TWO-LAYER STEEL FIBERED HIGH-PERFORMANCE CONCRETE BEAMS

ABSTRACT This study evaluated Life-Cycle Assessment (LCA) of two different designs of high-performance concrete beam: (1) a single-layer beam (SLB) that consisted of steel fibered high-strength concrete in both the compression and tensile zones and (2) a two-layer beam (TLB) that consisted of steel fibered high-strength concrete and normal-strength concrete in the compression and tensile zones, respectively. The SLB and steel fibered high-strength concrete layer of the TLB were of the same concrete class C70/85. LCAs of the SLB and TLB were conducted using the ReCiPe2016 midpoint and endpoint-single-score methods. The difference between the two endpoint-single-score results was evaluated using a two-stage nested analysis of variance. The ReCiPe2016 midpoint results showed that replacing the SLB with the TLB reduces the environmental impact of global warming potential, terrestrial ecotoxicity, water consumption, and scarcity of fossil resources by 15%, 17%, 11%, and 17%, respectively. The ReCiPe2016 endpoint-single-score results showed that the environmental damage from the TLB compared to the SLB was statistically reduced (p = 0.0256). Therefore, considering two different designs of steel fibered high-strength concrete beams, the TLB design was found environmentally preferable to SLB design on both, midpoint and endpoint-single-score evaluations.

IMPACTS OF BUILDING FUNCTION ON NORMALIZED-STEAM CONSUMPTION: ANALYSIS OF FLOOR AREA NORMALIZATION VERSUS LINEAR REGRESSION ON HEATING DEGREE-DAYS IN A HEATING-DOMINATED CLIMATE

ABSTRACT Linear regression analysis is one the most common methods for weather-normalizing energy data, where energy versus degree-days is plotted, quantifying the impacts of outside temperature on buildings’ energy use. However, this approach solely considers dry-bulb temperature, while other climate variables are ignored. In addition, depending on buildings’ internal loads, weather impact can be less influential, making the linear regression method not applicable for energy data normalization in internally driven buildings (such as research laboratory buildings, healthcare facilities, etc.). In this study, several existing buildings from different categories, all located on the University of Massachusetts Amherst campus and exposed to the same weather conditions in a heating-dominated climate, were analyzed. For all cases, regression of monthly steam use on heating degree-days and floor-area normalized steam data were used, investigating applicability of the former when the latter changes. It was found that internal loads can skew steam consumption, depending on the building functionality, making the effect of degree-days negligible. For laboratory-type buildings, besides heating and domestic hot water production, steam is also used for scientific experiments. Here, daily occupancy percentage, even during weekends and holidays, was higher than that of other buildings, indicating the intensity of scientific experiments performed. This significantly impacted steam consumption, resulting in higher floor-area-normalized steam usage. In these cases, steam use did not provide an outstanding correlation to heating degree-days. Whereas, for cases with other functionality-types and lower floor-area normalized steam, coefficients of determination in regressions were high. This study concludes that even for buildings located in the same climate, depending on how building functionality and occupancy schedule influence floor-area normalized steam use, multivariate linear regression can provide more accurate analysis, rather than simple linear regression of steam on heating degree-days.

AN INVESTIGATION BY THE BEP-TR METHOD OF THE EFFECT OF OBSTRUCTION ANGLE PARAMETER ON LIGHTING ENERGY PERFORMANCE AND DAYLIGHT SUPPLY

ABSTRACT Following the EN 15193, 2008 Energy Performance in Buildings Regulation in the European Union Member States, a comprehensive calculation can be made on lighting energy performance and daylight effect. This improved model accounts for Turkey’s “BEP-TR” (“Regulation on Energy Performance in Buildings”). In the present study, the effect of the obstruction angle parameter of buildings on lighting energy consumption and daylight provided is examined through a sample hotel project by the BEP-TR calculation method. This study investigates the effect of daylight on lighting energy performance alternatives that were produced according to the height, building distance variations (causing obstruction angle), and the correlation between annual lighting consumption values, daylight supply factor, and obstruction parameters. Accordingly, the current study aims to develop a method to assist zoning regulations, building intervals, and height decisions by determining specific ratios between obstruction parameters, daylight supply factor and lighting energy consumption values. Results of this study clearly show that obstruction parameter variables affect both the daylight supply factor and annual lighting energy significantly.

INDOOR ENVIRONMENTAL QUALITY IN THE JORDANIAN CONTEXT: INFLUENCE ON OCCUPANTS’ SATISFACTION

ABSTRACT The applicability of building rating systems has gained attention for achieving indoor environmental quality. Considering the wider internationalized recognition of LEED (Leadership in Energy and Environmental Design) and other rating systems, the case of Jordan provides a sense of particularity in consideration to its rather recent history in acknowledging these progressive standards. Utilizing a mixed approach based on paired comparisons between local LEED and non-LEED certified buildings, this research paper explores the level of satisfaction pertaining to Indoor Environmental Quality of building occupants. While it touches on the generality of such satisfaction, it proceeds to unpack and investigate how it resonates with the sustainability of the building measured through various means. The research outcomes reflected an overall appeal of LEED certified buildings and a decent level of comfort of their dwellers. Yet, it conveyed a vague, rather sporadic relation when comparing the subjective perception to the objective measures due to multiple potential reasons. The paper concludes by stressing the need for further appropriation of international environmental codes to better suit the local context. It lays a reliable foundation for further research, utilizing more case studies and exploring the applicability of rating systems in Jordan.

ENERGY AND WATER PERFORMANCE OF AN OFF-GRID TINY HOUSE IN CALIFORNIA

ABSTRACT The impetus for buildings to decarbonize and move towards radical energy and water efficiency is increasingly strong and identified as a priority within the green building sector. The tiny house movement offers an opportunity to both address the challenges of affordable housing and contribute to residential building decarbonization. Tiny houses de-emphasize mass consumption and excessive belongings and have potential to address equity issues such as gentrification by providing living spaces to low-income residents in desirable housing locations. This paper analyzes the Tiny House in My Backyard (THIMBY) project, investigating building sustainability concepts through the design-build-occupy process in a three-year-old structure. THIMBY demonstrates energy and water efficiency technologies inside an award-winning small living space (18.5 m2). THIMBY was designed to reduce energy and water use by 87 and 82% compared to California residential averages. In practice, it has reduced site energy by 88% and has emitted 96% fewer carbon emissions than a 2100 square foot California Energy Commission 2016 Title 24 minimally compliant home. We discuss the differences between design and performance of energy and water systems, which we find offer important lessons for the further expansion of the tiny house movement and other alternative and micro green housing types. We find that optimizing such houses through integration of energy and water saving technologies, home energy management systems, and strong communication between modelers, builders and occupants will be essential to achieving dramatic energy (87%), water (82%), and carbon (96%) savings.

ENHANCING THE DAYLIGHT AND ENERGY PERFORMANCE OF EXTERNAL SHADING DEVICES IN HIGH-RISE RESIDENTIAL BUILDINGS IN DENSE URBAN TROPICS

ABSTRACT This study examines the daylight and energy performance of 27 external shading scenarios in a high-rise residential building in the urban tropics. The cooling energy, daytime lighting energy and the spatial daylight autonomy (sDA) of the building model were simulated in Rhino3D and Grasshopper simulation software. The best performance scenario (vertical and horizontal shading on the twentieth floor, horizontal shading only for the eleventh floor and no shading for the second floor) satisfied 75 sDA(300lx|50) with corresponding annual enery performance of 16%–20% in the cardinal directions. The baseline scenario, which is the current practice of providing balconies on all floors, reduced daylight to less than 75 sDA on the eleventh and second floor, even though it had higher annual enery performance (19%–24%) than the best performance scenario. Application of the design principles to a case study indicated that 58% of the spaces had over 75 sDA for both Baseline and Best performance scenarios, while an increase in enery performance of 1%–3% was found in the Best performance scenario compared to the Baseline.

GLOBAL POLICIES ON GREEN BUILDING CONSTRUCTION FROM 1990 TO 2019

ABSTRACT Green Building Construction (GBC) is considered as an advancement towards sustainable development and providing a balance among health, economics, and social problems. Many countries have adopted various policies for GBC according to their conditions and regulations, including incentives and deterring programs. This study reviews a scientometric analysis of some published articles on the policies, incentives, and barriers to GBC from 1990 to 2019. The required data has been collected from the Web of Science (WoS) database, and then analyzed using Histcite, CiteSpace, and VOSviewer software. To accomplish this study, many items have been identified and ranked such as top journals, keyword co-occurrence networks, cluster analysis, the strongest citation burst, co-citation articles, most citations per year, and countries’ contribution to publishing, for the last three decades. Examining the trend of changes in publication of the related papers and interpretations of the analyses can be used for future research in each of the components, in addition to the creation of a knowledge-based view of past studies.