Sustainable Design Principles for Green Office Buildings: A Comprehensive Review

ABSTRACT


INTRODUCTION
The notion of green building (GB) has risen tremendously as a study issue in recent years as a result of the growing tensions between vast construction growth and environmental deterioration [1].Sustainable and environmentally friendly architecture is one of the primary goals that have been founded as the ultimate model for all their activities to create a better life [2].As a result, moving toward greener architecture is well-thought-out the main goal of today's architecture.Green building practices can play an important role in achieving sustainability in the construction industry, and the construction industry has made efforts to develop green building practices over the last two decades [3].Green architecture offers a range of benefits across environmental, social, and economic dimensions.Environmentally, it reduces pollution, conserves natural resources, and mitigates environmental degradation [4].Economically, it lowers operational costs for water and energy while enhancing user productivity.Buildings serve as shelters from natural elements but also impact health and the environment [5].The emergence of "green building" or sustainable building reflects growing awareness of environmental impacts.It involves creating healthier and more resource-efficient structures across their lifecycle, integrating aspects like resource efficiency, building performance, and occupant well-being [6].
Recent emphasis has shifted towards enhancing occupants' experiences, driven by research on indoor environment effects.Energy-saving measures, while beneficial, can inadvertently lead to health issues like Sick Building Syndrome due to compromised indoor air quality.Symptoms range from mild discomfort to severe health issues like carbon dioxide poisoning [7].Sustainable office building design reduces environmental impacts, energy consumption, indoor environmental quality, and climate change resilience.It prioritizes energy efficiency, high-performance insulation, advanced lighting systems, and smart automation.These buildings align with corporate social responsibility goals, attract environmentally conscious customers, and meet regulatory compliance.They create healthier, efficient, and resilient workplaces for future generations.
In this regard, the manuscript stresses the importance of green building design in achieving sustainability, particularly in modern offices.It aims to create efficient, productive, and environmentally sustainable workspaces through the integration of sustainable principles.The research involves a literature review and case studies of two office buildings to identify key indicators for sustainable design.The manuscript explores guidelines based on contemporary technology and ecological considerations, highlighting the need for energy reduction through renewable sources and rationalized electric energy use.The research contributes to the advancement of green building practices, providing practical guidance for architects, policymakers, and stakeholders working towards sustainable development in the built environment.

Research importance
The present study holds significance as it delves into the foundations and tenets of sustainable design for green office buildings.This is in line with the contemporary demand to create real estate infrastructure that is in step with environmental progress and lessens the adverse effects of conventional construction on the environment and society.This study is important because it offers a thorough understanding of the concepts and methods that can be applied to the design of green office buildings.This will help investors, developers, and architects make well-informed choices and carry out environmentally and energy-conscious business ventures.

Research questions
1. What are the cornerstones of sustainable design for environmentally friendly office buildings?
2. What methods and tools are employed in the construction of green office buildings?

GREEN OFFICE BUILDINGS
In general, "green buildings" are structures that prioritize resource efficiency (e.g., energy, water, and materials) and sustainability (e.g., minimizing buildings' negative environmental impacts) [8].The US Environmental Protection Agency provides a commonly cited definition of green building: "Green building is the practice of creating buildings and using processes that are environmentally responsible and resource-efficient throughout a building's life-cycle, from siting to design, construction, operation, maintenance, renovation, and deconstruction."Green building uses less energy and materials in its construction and operation while polluting and harming natural systems as little as possible.Green architecture, also referred to as sustainable or ecofriendly architecture, involves designing and constructing buildings in a manner that minimizes environmental impact [6].
Green buildings integrate with the local climate, traditions, culture, and environment.Green buildings can sustain and improve human life while also preserving the capacity of the ecosystem on a local and global scale.Green buildings make better use of resources, save money on operations, and boost workplace productivity.Green construction conveys the right message about a company or organization: that it is well-run, responsible, and committed [9].
It also makes efficient use of resources, saves money on operations, and boosts workplace productivity.Finally, building green sends the right message about being committed, organized, and accountable for the future.Research indicates that green buildings (GBs) can significantly enhance sustainability, promoting recycling, energy efficiency, ecological preservation, and reducing CO2 emissions through collaboration among government, researchers, and customers [1].
A green office building is a long-term, environmentally conscious construction that reduces environmental impact while offering a healthy work environment.It has energy-efficient lighting, innovative HVAC systems, recyclable materials, and natural light, all of which promote employee well-being and productivity.Green office buildings strive for LEED certification, which contributes to resource-efficient urban settings [10].

OFFICE BUILDINGS CHARACTERISTICS
Office buildings today are designed with specific characteristics to enhance productivity and collaboration among employees (Figure 1).An open-plan work environment, characterized by large hubs and various options, promotes social interactions, teamwork, and focused work across different administrative areas, reducing isolation and encouraging concentration [11,12].Collaborative and quiet spaces are integrated into modern office designs, featuring communal hubs that serve multiple functions and eliminate the need for separate facilities for teams or organizations [13].The application of technology is crucial, with a focus on providing employees with the necessary tools for effective work, emphasizing the use of new technologies that enhance mobility and efficiency [6].Flexibility and mobility are key aspects of office design, creating dynamic environments with diverse technologies, spaces, and settings to prioritize collaboration, concentration, and service delivery over traditional workstations, ultimately boosting organizational culture and productivity [14].Consistent design plays a role in facilitating employee adaptation to new areas efficiently, saving time and costs associated with changes, while offering a uniform and generic workplace design [7].Additionally, the choice of workplace environment allows employees to select from various work settings, encouraging the use of mobilityenabling technologies that enable work from different locations within the building or even remotely [14].

PRINCIPLES OF GREEN BUILDINGS
The principles of green buildings revolve around sustainability, energy efficiency, and environmental responsibility.These principles encompass a range of strategies aimed at reducing the environmental impact of buildings.Energy efficiency is achieved through the use of energy-efficient lighting, appliances, and HVAC systems.Renewable energy sources, such as solar panels and wind turbines, are integrated to provide clean power.Water conservation is also a key principle, with the use of low-flow fixtures and rainwater harvesting systems.Sustainable materials, including recycled or locally sourced materials, are chosen to reduce the carbon footprint of construction.The design of green buildings focuses on maximizing natural light and ventilation, reducing the need for artificial lighting and mechanical systems.Waste reduction and recycling strategies are implemented to minimize the environmental footprint during construction and operation.Additionally, green roofs or living walls are incorporated to enhance insulation, mitigate the heat island effect, and provide green spaces for occupants.The indoor air quality is optimized through the selection of materials and ventilation systems that promote the health and well-being of building occupants.Smart building technologies are integrated for energy management, lighting control, and overall building automation to optimize resource use.Finally, green buildings encourage the use of alternative transportation options, such as bike racks, public transit access, or electric vehicle charging stations, to reduce reliance on fossil fuels [15,16].
These principles collectively contribute to creating a sustainable and environmentally friendly office building (Figure 2).

MATERIAL AND METHODS
In order to conduct a thorough literature review and provide a solid foundation for understanding sustainable principles in the design of green office buildings, this manuscript employs a qualitative research approach.In order to fully explore the complexities of sustainable architecture, the qualitative approach was selected.This allows for a nuanced investigation of important ideas, emerging trends, and industry best practices.

Data collection
Scholarly journals, publications, and reports on green office building design and sustainable architecture served as the source of the data for this study.We'll use reliable databases like Scopus, Web of Science, and Google Scholar to perform a thorough search.The search function will be guided by keywords like "green office buildings," "sustainable architecture," "energy efficiency," and "renewable energy".

Inclusion criteria
The inclusion criteria for selecting literature will encompass publications focusing on sustainable office building design, including peer-reviewed articles, reports, and academic books, to maintain academic rigor.

Data analysis
The collected literature will undergo thematic analysis, whereby key themes and patterns related to sustainable principles in green office building design will be identified and synthesized.This process will involve coding and categorizing the data to extract meaningful insights and trends.

Rationale for qualitative approach
The qualitative approach was chosen for its ability to provide in-depth insights and understanding of complex phenomena, such as sustainable architecture.By exploring the nuances and intricacies of sustainable principles in green office building design, this approach allows for a richer and more nuanced analysis compared to quantitative methods.Additionally, qualitative research is well-suited for synthesizing diverse perspectives and interpretations present in the literature.

Limitations
It is important to acknowledge the limitations of the qualitative approach, such as potential subjectivity in data interpretation and the reliance on existing literature, which may not capture the most recent developments in the field.Additionally, the scope of the study may limit the generalizability of findings to broader contexts.
Energy efficiency involves minimizing waste and maximizing output in building design.Renewable energy sources, such as solar, wind, hydroelectric, and geothermal energy, are used to generate clean and sustainable power.Water conservation involves efficient use and management of water resources, such as low-flow fixtures and rainwater harvesting systems.Sustainable materials, such as recycled or renewable resources, minimize environmental impact and reduce carbon emissions.Natural lighting and ventilation use natural daylight and airflow, reducing the need for artificial lighting and mechanical ventilation.Waste reduction and recycling minimize waste generation and maximize material reuse.Green roofs and green spaces improve stormwater management and biodiversity.Indoor air quality is maintained through controlling pollutant sources and utilizing air filtration systems.Smart building technology integrates automation and control systems to optimize performance.Transportation alternatives promote sustainable commuting and reduce reliance on single-occupancy vehicles.Innovation explores new technologies and design approaches to advance sustainability.Certificates of sustainability, like LEED, validate a building's environmental performance and serve as a benchmark for sustainable design and construction practices.

The Crystal -London, United Kingdom
The Crystal in London is a sustainable office and commercial structure with advanced environmental features, LEED Platinum and BREEAM Outstanding certifications, offering conference, exhibition, and office spaces for sustainable events and business activities, as show in Figure 3 [4].Perspective of the crystal project.c.Layout of the crystal project [17] The Crystal, a 2,000-square-meter exhibition space, hosts the world's largest exhibition on sustainable mobility, building technologies, power, water supplies, and healthcare, using highly insulated glass for cost reduction [17].
The building is entirely electric, energy-efficient, and water-self-sufficient, with on-site rainwater harvesting and treatment.To ensure peak performance, the design is monitored for live streaming of performance figures and constant tuning.The building is 90% self-sufficient in water and has an approved drinking water safety plan.Features can be summarized in points in Table 1 [4].
The building aims to foster sustainable cities through collaboration, research, and new technologies.It explores sustainable mobility, power, water supply, building technologies, and healthcare, promoting future possibilities, as shown in Figure 4.
All the green features and principles achieved by the two building are shown in Table 2.

The Council House 2, Melbourne
Fresh air is flowing into the interior spaces of a Melbourne City Council building through the ground vents and seeping down through the wall ducts [18,19] (Figure 5).The stack effect, which the architect used to move hot and exhausted air out of the building through roof gaps of shafts up to the wind turbines, was inspired by termite mounds (Figure 6) [20].Automatic shading louvers are put on the western faç ade to block the undesirable hot sun [21].building [21] Table 1.Green principles of the Crystal -London, United Kingdom and the Council House 2 Office Building, Melbourne

Principles to Design Green Office Buildings
The Crystal -London, United Kingdom The Council House 2 Office Building, Melbourne

Energy Efficiency
The building is an all-electric facility, utilizing photovoltaic solar panels, LED and fluorescent light shades, high-efficiency ventilation, chilled beams, and seasonal cooling and heating pumps.
The project targets substantial reductions in electricity consumption by 85%, gas consumption by 87%, as well as building energy use reduction by 50%.

Renewable Energy Sources
IT and "small power" consume 63% of the total energy output of the building, while heating and cooling use the remaining 37%.
CH2 incorporates moderate climate faç ades, tapered ventilation ducts, daylighting strategies, and an undulating concrete floor structure for heating and cooling.Water Conservation A 90% water-self-sufficient crystal, collects rainwater while treating sewage.A 72% water-self-sufficient, collects rainwater.

Sustainable Materials
The building features cutting-edge technology that helps it run more efficiently.The structure includes black water treatment, rainwater harvesting, solar heating, and an automated building management system.
The building features cutting-edge technology that helps it run more efficiently.Environmental features include black water treatment, rainwater harvesting, solar heating, and an automated building management system.

Natural Lighting and Ventilation
The vertical facade system is made up of 39% transparent glass and 61% insulated panels, with a total U-value of 1W/m2K, ensuring that the building operates in multiple ventilation modes and that users have control over temperature, light, and air.
Wavy ceilings, light shelves, large and small windows, color accents, and shared windowed areas for non-owned individuals all contribute to the design of CH2.Building facade ventilation stacks channel air, with north stacks absorbing heat and south stacks reducing it, providing shade for office windows and encouraging warm air circulation.As a result, the facade is animated in direct response to external conditions.This is biomimicry at its finest: the building moving and coming to life in response to its surroundings.

Waste Reduction and Recycling
Rainwater is collected and cleaned to provide safe drinking water.Furthermore, black water is being used on the site.67% of the concrete aggregate used in the building's construction came from secondary sources (i.e., waste material); 100% recycled steel was used for building reinforcement, and the roof is made entirely of recycled aluminum.As well as, 94% of construction waste was recycled.
Automated shading louvers, crafted from recycled timber, mitigate unwanted solar heat on the western facade.

Green Roofs and Green Spaces
1,580sq m of solar PV panels on the roof are expected to generate 256MWh per year, accounting for approximately 17.5% of the building's predicted (average) energy consumption; 19sq m of solar thermal panels are expected to generate an additional 11.9 MWhT per year.the roof has a U-value of 0.181W/m2K.
The north-facing faç ade features steel trellises, balconies, and vertical gardens, providing shade and reducing indoor glare, while light shelves reflect natural light.CH2's design optimizes natural light through wavy ceilings, light shelves, large and small windows, color accents, and shared windowed areas for non-owned individuals.

Indoor Air Quality
Two ground-source heat pumps that can simultaneously heat and cool provide space heating and cooling.
Notably, the building guarantees 100% fresh air circulation to occupants, with complete air turnover every half hour.

Smart Building Technology
The building has its own grounded source heat pump that provides heating and cooling.Additionally, a selfsufficient water treatment plant ensures high-quality drinking water.
The southern faç ade features shower towers that cool air above street level, providing cool air to retail spaces and precooling chilled water panels.These lightweight fabric tubes have a temperature drop of 4-13 degrees Celsius.

Transportation Alternatives
The project also explores future possibilities for sustainable mobility, energy, water supply, and building technologies [17].
Council House 2 (CH2), a holistic system that integrates city and nature, was created in collaboration with Melbourne's City of Melbourne.in which all parties depend on one another to ensure the building functions correctly.Council House 2 in Melbourne, Australia, encourages sustainable transportation by providing public transportation, bicycle facilities, designated bike parking spaces, hybrid car use, and shower facilities.These initiatives promote environmentally friendly and active transportation, lowering carbon footprints and encouraging employees and visitors to use environmentally friendly methods.

Innovation
Other renewable energy resources can be used to meet the building's remaining energy requirements.Furthermore, other advanced technologies can be used to improve the building's infrastructure.
Council House 2, which aimed to be a model of sustainable and innovative design at the time, has left a legacy that can be seen in later Garden City developments.DesignInc, in collaboration with the City of Melbourne, created an office building with contemporary principles in mind that has proven to be a wise investment for the council and the city itself, ensuring it remains the City of Melbourne's long-term base of operations.

Certificates of sustainability
The Crystal has garnered numerous awards spanning sustainability, design, architecture, events, tourism, and -The Green Building Council of Australia awarded CH2 a Green Star rating as an environmentally friendly building.health and safety, including LEED Platinum, BREEAM Outstanding, Green Apple, ISO 14001, BCO Office, and RICS awards.
-The Australian Institute of Architects (AIA) awarded CH2 the National Award for Sustainable Architecture.-The United Nations Environment Global Awards recognized CH2 in the Sustainable Infrastructure category.These awards serve as visible acknowledgments of the community's appreciation for CH2's environmental conservation efforts and achievement of high sustainability standards in both design and operation.

PRINCIPLES TO DESIGN GREEN OFFICE BUILDINGS
The exploration of two exemplary green office building projects, namely The Crystal and The Council House 2, has provided valuable insights into the innovative and sustainable practices that can be integrated into the design of administrative spaces.These case studies have illuminated the intersection of architectural ingenuity, environmental consciousness, and operational efficiency, showcasing how a harmonious balance can be achieved for the benefit of both occupants and the planet.As we dissected the features of these projects, it became evident that sustainability goes beyond energy-efficient systems and recycled materials; it is a holistic approach that encompasses site selection, water conservation, indoor environmental quality, and community impact.
The legacy of sustainable design lies not only in the physical structures we create but in the enduring impact they have on the communities they serve and the planet we all share.Let these principles guide the future of green office building design, fostering a new era where sustainability is not just a goal but an inherent and inseparable part of our built environment.Given the availability of all the principles of sustainability in the two projects, green indicators of the projects can be deduced as principles of designing green office buildings as shown in Table 3.

Building
Principles to Design Green Office Buildings The Crystal 1. Self-Shading Concept self-shading is essential, where proper consideration of how structures cast shadows on themselves can influence aesthetics, energy efficiency, and functionality.This phenomenon underscores the importance of accurate lighting and shadow modelling in these disciplines, contributing to the creation of more lifelike and visually appealing designs.

Energy Efficiency
Utilizing photo-voltaic solar panels, LED and fluorescent light shades, high-efficiency ventilation, chilled beams, and seasonal cooling and heating pumps

Environmentally Friendly Materials
Select sustainable and recyclable building materials to minimize the project's environmental impact.

Water Management
Utilize water-saving techniques, such as rainwater harvesting systems and water purification, to reduce water consumption.Integrate water-saving technologies, such as high-efficiency faucets and toilets. 5. Smart Building Technology using a heat pump that generating its energy and an independent water treatment plant for high-quality drinking water.

Waste Reduction and Recycling
Rainwater is collected and cleaned to provide safe drinking water.Furthermore, black water is being used on the site.

Sustainable Mobility
Sustainable mobility is the use of environmentally friendly transportation methods, promoting energy efficiency and ecological balance.It includes electric and hybrid vehicles, public transportation, cycling infrastructure, and pedestrian-friendly urban planning.

Vertical Gardens
Vertical gardens, or green walls, are a popular sustainable urban design solution, offering aesthetic appeal, environmental benefits, air purification, thermal insulation, and psychological benefits, promoting harmony with nature.

Faç ade Design
Transparent glass and insulated panels are essential in modern architecture, balancing aesthetics, energy efficiency, and functionality.Transparent glass creates visually inviting spaces, while insulated panels reduce energy consumption and contribute to sustainable building practices.Together, they create visually appealing, environmentally conscious, and energy-efficient structures.
The Council House 2

Biomimetic Concept
Using biomimicry or nature simulation to design green office buildings, whether for the interior or exterior envelope.Biomimicry is an important and effective principle that increases the vitality and sustainability of a building, reduces energy consumption, and treats the building as an extension of nature.To function, the building, as a living thing, needs all of its limbs and parts.The epidermis is the skin's outer layer that protects it from the elements; the skin of a building should be the same.

Environmentally Friendly Materials
Select sustainable and recyclable building materials to minimize the project's environmental impact.It is suggested that phase change material be used to cool the water for the chilled beams and panels.This is frequently referred to as the building's "battery" because it stores the coolth for later use.

Vertical Gardens
Vertical gardens, or green walls, are a popular sustainable urban design solution, offering aesthetic appeal, environmental benefits, air purification, thermal insulation, and psychological benefits, promoting harmony with nature.

Water Management
Utilize water-saving techniques, such as rainwater harvesting systems and water purification, to reduce water consumption.

Courtyards and Stack Effect
Courtyards enhance architectural design, providing aesthetic and functional benefits.They contribute to efficient natural ventilation, energy savings, and natural light, promoting indoor air quality and comfort.

Double Wall Design
Double-wall construction enhances architectural design by providing insulation, thermal performance, energy efficiency, and sound insulation.It promotes temperature regulation, quieter indoor environments, and versatile material integration.

Ceiling Design
The pre-cast concrete vaulted ceilings with wavy designs possess a high thermal mass, aiding in daytime cooling by absorbing excess heat, which is then expelled during nighttime purging.

Promoting Alternative Transportation
Provide bike parking areas and improve access to alternative modes of transportation such as buses and trains.

Flexible Design
Construct buildings that can be adapted and upgraded in the future to meet evolving technological and changing needs.

CONCLUSIONS
This manuscript underscores the critical need for sustainable building practices, with a specific focus on addressing the high energy consumption rates prevalent in office buildings.Traditional construction methods have long been associated with environmental harm due to their heavy reliance on energy, water, and raw materials, as well as their contribution to waste generation and pollution.In contrast, green buildings represent a transformative approach towards more sustainable and resource-efficient structures, championing environmental stewardship and sustainability.The global trend of green architecture highlights the importance of creating buildings that harmonize with their surroundings and minimize their environmental impact.Architects are key players in this shift, tasked with implementing innovative strategies to reduce energy consumption in office buildings, such as the incorporation of renewable energy sources like solar and wind power.The manuscript emphasizes sustainable indicators and principles essential for the conversion of traditional office buildings into green, eco-friendly structures.It stresses the urgency for architects to prioritize energy efficiency through the adoption of renewable energy sources and the rationalization of electric energy usage.Ultimately, this research contributes to the ongoing discourse on green building practices, offering practical guidance for architects, policymakers, and stakeholders committed to promoting sustainable development within the built environment.
The review highlighted the importance of incorporating energy efficiency measures, renewable energy sources, water conservation strategies, and sustainable materials into the design and construction of green office buildings.By prioritizing natural lighting and ventilation, waste reduction and recycling, and the integration of green roofs and green spaces, these buildings can minimize environmental impact and promote occupant health and well-being.
Furthermore, the review underscored the significance of indoor air quality, smart building technology, and transportation alternatives in creating sustainable and resilient office environments.Embracing innovation and pursuing certifications of sustainability, such as LEED certification, are crucial steps toward achieving high-performance green office buildings.
In essence, this comprehensive review serves as a valuable resource for architects, developers, and investors seeking to advance sustainability in office building design.By adopting these sustainable design principles and incorporating them into future projects, we can pave the way for a greener, healthier, and more sustainable built environment for generations to come.
The comprehensive analysis of these projects has allowed us to distill a set of critical standards and principles for designing sustainable green office buildings.The journey has underscored the importance of prioritizing passive design strategies, harnessing renewable energy sources, and integrating smart technologies to optimize resource consumption.Furthermore, the significance of selecting ecofriendly materials, implementing efficient waste management systems, and fostering a connection with the surrounding environment has become increasingly apparent.
These case studies have reaffirmed that a successful green office building is not merely a structure but a living, breathing entity that contributes positively to the well-being of its occupants and the ecosystem at large.The synthesis of our findings has led to the identification of key pillars: energy efficiency, water conservation, material selection, indoor air quality, and social responsibility.These pillars form the foundation upon which future sustainable green office buildings should be designed.
The principles proposed for designing efficient and sustainable management buildings that combine energy efficiency, increasing staff productivity, and improving the internal environment are outlined in the following criteria.
1. Linking and interconnecting office systems and spaces, and external environment.
2. Biomimetic concept and biomimetic skin achieved sustainability aids in design efficient design, and achieve better results according to design, IEQ, and users.
3. Double skin provides passive protection from direct sunlight while also limiting the amount of heat entering from the outside and serves both thermal and aesthetic functions.
4. The green elements such as green atrium, green roofs, and open-air elements illuminate the structure while also providing natural ventilation and a good view, as employees can enjoy the magnificent surrounding scenery while working or relaxing.
5. Using phase change material is used to cool the water for the chilled beams and panels.
6.The last design element, shower towers integrated into the facade, contribute to regulating the indoor air environment.
7. The pre-cast concrete vaulted ceilings with wavy designs possess a significant thermal mass.This feature assists in maintaining cooler building spaces during the day by absorbing excess heat, which is subsequently expelled during the nighttime purging process.

Figure 3 .
Figure 3.The crystal project.a. Plan of the ground floor.b.Perspective of the crystal project.c.Layout of the crystal project[17]

Table 2 .
Green principles of the Crystal -London & Council House 2