Large-scale Office Building Research Articles

Significant Implication of Optimal Capacitor Placement and Sizing for a Sustainable Electrical Operation in a Building

The improvement of energy efficiency plays an important role to ensure sustainable electrical operation in large-scale buildings. In relation to the low-cost electrical components, a capacitor is an electrical component that can be used to sustain or improve the operating performance of an unbalanced electrical system in large-scale buildings so that energy efficiency improvement can be obtained. This is important to overcome the ineffective utilization of energy caused by the occurrence of power losses in an unbalanced electrical system of large-scale buildings. Further improvement of energy efficiency can be obtained by reducing an excessive amount of incoming power through the determination of tap setting for incoming transformer, and this is classified under the concept of conservative voltage regulation (CVR) approach. In order to solve the problem, the optimal capacitor placement and sizing (OCPS) with CVR is introduced as a new approach for energy efficiency improvement while ensuring a sustainable operation in an unbalanced electrical system of large-scale buildings. The proposed technique utilizes the artificial intelligence (AI) based differential evolution particle swarm optimization (DEPSO) technique with the objective function of total cost minimization for the real power losses, real power consumption, and capacitors installation. The effectiveness of the proposed technique to achieve energy efficiency improvement is investigated through a case study of an unbalanced electrical system in a large-scale office building. The significance of the research output is related to its low-cost technology that has the potential for a comprehensive, pragmatic implementation in large-scale buildings, and subsequently, it will significantly accelerate the increase of national agenda in energy efficiency.

Factors Affecting Energy Performance of Large-Scale Office Buildings: Analysis of Benchmarking Data from New York City and Chicago

Buildings in high-income, industrialized cities are responsible for more than 50% of global energy consumption; consequently, many developed cities have legislated energy benchmarking and disclosure policies to understand their buildings’ energy-use dynamics better. By utilizing these benchmarking data and additional information taken from 3D models, this paper presents a comprehensive analysis of large-scale office buildings located in New York and Chicago, with respect to their energy use intensity (EUI). To identify the primary factors affecting the EUI, Spearman’s correlation analysis and multiple variate regression tests were performed on office buildings over 500,000 ft2 (46,452 m2) gross floor area. The results showed the number of floors, construction year, window-to-wall ratio (WWR), and source-to-site ratio statistically significant, while morphological factors such as the relative compactness and surface-to-volume ratio showed limited relation to EUI. In New York City, the smallest EUI median was found in the buildings with 20 to 30 floors, and in Chicago, the buildings with 60 floors or more. A higher source-to-site ratio generally had lower overall EUI in both cities. Despite the high correlation, different kinds of dependency were found for window-to-wall ratio (WWR) and construction year between NYC and Chicago. These findings highlight the relative role that each building’s characteristics play concerning the EUI, depending on the particular building’s typology, scale, and the urban context.

大規模オフィスビルでの中温冷水を利用した高効率熱源・空調システムに関する研究 （第１３報）熱源改善工事概要および建物全体のエネルギー消費実績

大規模オフィスビルでの中温冷水を利用した高効率熱源・空調システムに関する研究 （第１３報）熱源改善工事概要および建物全体のエネルギー消費実績

Optimal Control Strategy for Variable Air Volume Air-Conditioning Systems Using Genetic Algorithms

This study is aimed at developing a real-time optimal control strategy for variable air volume (VAV) air-conditioning in a heating, ventilation, and air-conditioning (HVAC) system using genetic algorithms and a simulated large-scale office building. The two selected control variables are the settings for the supply air temperature and the duct static pressure to provide optimal control for the VAV air-conditioning system. Genetic algorithms were employed to calculate the optimal control settings for each control variable. The proposed optimal control conditions were evaluated according to the total energy consumption of the HVAC system based on its component parts (fan, chiller, and cold-water pump). The results confirm that the supply air temperature and duct static pressure change according to the cooling load of the simulated building. Using the proposed optimal control variables, the total energy consumption of the building was reduced up to 5.72% compared to under ‘normal’ settings and conditions.

Development of Wellness Architecture

By using index of wellness architecture such as WELL Building Standard, Takenaka Corporation had renovated and rebuild some projects to improve comfort and intelligent productivity from 2016. The purpose of this report is to give an overview of efforts and achievement in project we’ve done. In the case of large-scale office building renovation, we aim to obtain Well Building Standard certification. We introduce the efforts in the following evaluation items, consideration for the air environment such as whole building smoking cessation and consideration for the mind such as office layout that green is in sight. In the case of rebuilding dormitory for singles, we aim to create an educational dormitory that considers physical and mental health, safety and security, and the environment. We introduce approaches such as plan to promote communication, setting of sleep specialization room as place for creating the opportunity to know one’s own health condition and sleep rhythm. In the case of medium-sized office buildings, We introduce the office layout for a smart working, such as “Workplace to choose the place according to the activity”, the introduction of the wellness air conditioning system corresponding to the thermal individual comfort and the effect verification about the worker satisfaction

大規模オフィスビルでの中温冷水を利用した高効率熱源・空調システムに関する研究 （第１5報）二次側空調システムの負荷特性

大規模オフィスビルでの中温冷水を利用した高効率熱源・空調システムに関する研究 （第１5報）二次側空調システムの負荷特性

大規模オフィスビルでの中温冷水を利用した高効率熱源・空調システムに関する研究 （第１６報）電力・水消費量の分析

大規模オフィスビルでの中温冷水を利用した高効率熱源・空調システムに関する研究 （第１６報）電力・水消費量の分析

大規模オフィスビルでの中温冷水を利用した高効率熱源・空調システムに関する研究 （第12報）熱源最適運転支援システムの実績評価と考察

大規模オフィスビルでの中温冷水を利用した高効率熱源・空調システムに関する研究 （第12報）熱源最適運転支援システムの実績評価と考察

A study of city-level building energy efficiency benchmarking system for China

The city-level public building energy efficiency benchmarking system has an important guiding value for building energy-saving work, especially for Beijing, with its high energy-consumption density and both long heating and air-conditioning periods. This paper analyzed the characteristics of large-scale office buildings in Beijing and gives a detailed description of the process of establishing a public building energy efficiency benchmarking system for large-scale office buildings in Beijing, China, including data investigation and verification, Energy Usage Intensity(EUI) calculation, determining independent and dependent variables, developing and testing the benchmarking model, and deriving the benchmarking rating table. Then the first city-level public office building energy efficiency benchmarking system in China is established based on 88 large-scale office buildings in Beijing. The results showed that the model's performance index R2 is 0.667 and gives a good representation. The process has a strong potential for replication for other cities in China and even for a national energy-consumption evaluation system.

The Impact of Measurement Research on Prefabrication and Modulation in SOM’s Postwar Housing and Office Buildings

Skidmore, Owings, and Merrill (SOM) committed to innovations in prefabrication and modulation of construction in the mid-twentieth century. This paper examines SOM’s collaboration with the John B. Pierce Foundation in the 1940s, which advanced the firm’s technical and theoretical expertise on prefabricated housing and large-scale office buildings. The Pierce Foundation conducted research on prefabrication and ergonomics, and carried out physiological and psychological research in the domestic environment. Their extensive measurements of objects, building parts, and human activities in the domestic environment were crucial to SOM’s advancements in modulated office design. The Union Carbide Headquarters (1960) illustrates the impact of the measurement of physical and spatial dimensions on the modern corporate office building.

An Experiment on Heat Recovery Performance Improvements in Well-Water Heat-Pump Systems for a Traditional Japanese House

Concerns about resource depletion have prompted several countries to promote the usage of renewable energy, such as underground heat. In Japan, underground heat-pump technology has begun to be utilized in large-scale office buildings; however, several economic problems are observed to still exist, such as high initial costs that include drilling requirements. Further, most of the traditional dwellings “Kyo-machiya” in Kyoto, Japan have a shallow well. This study intends to propose an effective ground-source heat-pump system using the well water from a “Kyo-machiya” home that does not contain any drilling works. In previous research, it was depicted that the well-water temperature decreases as the heat pump (HP) is operated and that the heat extraction efficiency steadily becomes lower. In this study, an experiment is conducted to improve efficiency using a drainage pump. Based on the experimental results, the effect of efficiency improvement and the increase in the electric power consumption of the drainage pump are examined. It is indicated that short-time drainage could help to improve efficiency without consuming excessive energy. Thus, continuous use of the heat pump becomes possible.

大規模オフィスビルでの中温冷水を利用した高効率熱源・空調システムに関する研究 （第2報）空調システム概要とコイル性能検証

大規模オフィスビルでの中温冷水を利用した高効率熱源・空調システムに関する研究 （第2報）空調システム概要とコイル性能検証

大規模オフィスビルでの中温冷水を利用した高効率熱源・空調システムに関する研究 （第1報）建物概要と設備概要

大規模オフィスビルでの中温冷水を利用した高効率熱源・空調システムに関する研究 （第1報）建物概要と設備概要

B-55 大型事務所ビルにおけるコージェネレーション導入効果に関する研究

B-55 大型事務所ビルにおけるコージェネレーション導入効果に関する研究

Analysis of heat rejection from an actual large-scale air-conditioned office building by field measurements and numerical simulations

The actual value of the heat rejection through the cooling towers from the air-conditioning system of the typical large-scale office building is measured in the tropical summer climate of Shenzhen. The daily average measured value of the total heat rejection per unit building area is 82.75W/m2 during weekdays. During the weekend, this value is only 20.24W/m2, i.e., about 1/4 of that found for the weekdays, which is attributable to the less activity of building. The proportion of the sensible heat rejection is only 1.15%, and even attains a negative value when the inlet water temperature is lower than the inlet air temperature of the cooling towers. To evaluate quantitatively the effect of the heat rejection from the air-conditioning system on the urban thermal climate, the heat-rejection efficiency ratio (HRER) is presented in this study, for which the average measured value during weekdays is 1.35. In addition, a heat-rejection numerical model is developed, and the heat-rejection simulation results generally agree well with the field test data. The results indicate that the hot and humid climatic conditions impair the heat and the mass transfer efficiency of the cooling towers, and ultimately reduce the heat rejection from the building air-conditioning system.

大規模オフィスビルでの中温冷水を利用した高効率熱源・空調システムに関する研究 （第3報）熱源設備概要と運転実績

大規模オフィスビルでの中温冷水を利用した高効率熱源・空調システムに関する研究 （第3報）熱源設備概要と運転実績

Development of an energy evaluation methodology to make multiple predictions of the HVAC&R system energy demand for office buildings

Abstract HVAC&R systems are the most energy consuming building services, representing approximately half of the final energy use in the building sector. Despite their significant energy use, there is a lack of a consistent and homogeneous framework to efficiently guide research, mainly due to the complexity and variety of HVAC&R systems, but also to insufficient rigor in their energy analysis. Quantifying the energy consumption characteristics of HVAC&R system is complicated, because the energy savings provided by this system depend on various factors. This research evaluates energy consumption characteristics of HVAC&R systems, with the aim of establishing a common idea for the analysis of building energy efficiency. The objective of this study is to develop an energy evaluation methodology and a simple simulation program that may be used by engineers and designers to assess the effectiveness and economic benefits of HVAC&R systems. Our approach deals with the concept of HVAC&R system energy use aggregation levels that are composed of subsystems. To carry out a techno-economical estimation of HVAC&R systems considering different types of subsystems, the matrix combination analyzed, and a total of 960 HVAC&R systems can be implemented for a large-scale office building. The methodology of energy analysis that was carried out in this study highlights how to plan and design toward utilizing the most effective HVAC&R systems.

사무소 건물의 HVAC&R 시스템 에너지 분석방법 및 예측 프로그램 개발

HVAC&R systems are the most energy consuming building services, representing approximately half of the final energy use in the building sector. Despite their significant energy use, there is a lack of a consistent and homogeneous framework to efficiently guide research. This research is about the energy consumptions of HVAC&R systems, with the aim of establishing a common idea for the analysis of building energy efficiency. Our approach deals with the concept of an HVAC&R set that is composed of subsystems. A matrix combination evaluation is examined, and a total of 960 sets can be implemented in a large scale office building. A method as a tool for energy evaluations of HVAC&R systems, and HEET as a energy simulation program, were developed.

An online fault diagnosis tool of VAV terminals for building management and control systems

Abstract Proper design, reliable control and health of variable–air–volume (VAV) terminals are essential for reliable operation and energy efficiency of VAV air-conditioning systems. This paper presents an online fault diagnosis tool for pressure-independent VAV terminals and its implementation. The fault diagnosis tool is developed using a robust fault detection and diagnosis strategy for VAV terminals. Cumulative sum (CUSUM) control chart with estimated process parameters is utilized to detect faults in VAV terminals. A rule-based fault classifier is designed and utilized to find the sources of faults in VAV terminals. The fault diagnosis tool relies only upon the sensor data and control signals that are commonly available in building management control systems (BMCS). The fault diagnosis tool can be installed in BMCS to online read the operating data of all VAV terminals in a building through local area network and diagnose faults of VAV terminals in the building. The fault diagnosis tool has been validated in a large-scale office building located in Hong Kong and can effectively find all faults occurring in VAV terminals.

DIFFERENCE OF INDOOR AIR QUALITY WITH VARIOUS SCALES OF OFFICE BUILDINGS

To maintain indoor environments, large-scale buildings have been managed under the “Law for Maintenance of Sanitation in Buildings (established in 1970)” in Japan. Although the large-scale buildings are managed on the indoor environmental standard, the management statuses for small-scale buildings, for example, office buildings smaller than 3000m2 total floor areas, out of the law are not clear. This study carried out the field measurements of indoor particulate matter, volatile organic compounds (VOC) and airborne microbes both in large-scale office buildings and small-scale ones, and investigated the differences of indoor air quality. As a result, the particle matter concentrations, VOC concentrations and fungi concentrations for the small-scale offices were relatively higher level than the larger-scale ones. It became clear that low air exchange rates and low filtering efficiencies of the air filters in the small-scale buildings could be affect on indoor air quality.