scope:

INTRODUCTION

There continues to be a growing awareness about the impact of the built environment on the natural environment. The use of sustainable engineering concepts has evolved quite rapidly in recent years and is now well recognized in HVAC&R and related engineering professions. This in turn is being encouraged by increased client demand for more sustainable buildings, commonly called green buildings.

Interest in sustainable or green buildings (the distinction between the two is discussed below) has been particularly evident in the concern about energy and water resource consumption, but also includes broader concerns such as indoor environmental air quality, material use, and "smart" development and planning. Many countries in the world now have green-building rating systems (voluntary) and/or codes (mandatory) in some form or other. Organizations devoted to green buildings now exist in most countries. Even as the concept of green design is reaching mainstream acceptance, these organizations continue to promote these concepts, exhort the industry and society to action, strive to motivate industry practitioners and building owners, warn of consequences from ignoring these concepts, and instruct how to achieve green design.

ASHRAE identified a need for guidance on green building concepts specifically directed toward practicing professionals involved on a day-to-day basis in the mechanical/electrical/plumbing (MEP) building system design process. However, readers may find that this guide may also serve other needs-for example, as the basis for a university course in sustainable building design. From a survey conducted in 2011, a wider range of people now use the ASHRAE GreenGuide, including students and other professionals in related disciplines. The topics covered in this guide are global and thus there has been an effort to keep this guide applicable internationally.

Green is one of those words that can have many meanings, depending on the circumstances. One of these is the greenery of nature in the flora around us. This symbolic reference to nature is the meaning this term relates to in this publication. The difference between a green and sustainable design is the degree to which the design helps to minimize the building impact on the environment while simultaneously providing a healthy, comfortable indoor environment. When the term green is used, is commonly is thought of as focusing on the energy and resources involved, while sustainable is broader in scope and considers the three Ps: people, profit and planet. However, some may not recognize a difference between the two terms and use them interchangeably; this is also the general approach taken in this book. This guide is not intended to cover the full breadth of sustainability, as this would require and extensive series of volumes, but it is a good overview of the main topics and issues involved. For additional key characteristics and detailed discussion of sustainability in buildings and the built environment, refer to the "Sustainability" chapter in the ASHRAE Handbook-Fundamentals (ASHRAE 2017a).

It is important to note that the definition of green buildings places an emphasis on integrated design of mechanical, electrical, architectural, and other systems. Specifically, a green/sustainable building design is one that achieves high performance, over the full life cycle, in the following areas:

• Minimizing natural resource consumption through more efficient utilization of nonrenewable energy and other natural resources, land, water, and construction materials, including utilization of renewable energy resources to strive to achieve net zero energy consumption.

• Minimizing emissions that negatively impact our global atmosphere and ultimately the indoor environment, especially those related to indoor air quality (IAQ), greenhouse gases, global warming, particulates, or acid rain.

• Minimizing discharge of solid waste and liquid effluents, including demolition and occupant waste, sewer, and stormwater, and the associated infrastructure required to accommodate removal.

• Minimizing negative impacts on the building site.

• Optimizing the quality of the indoor environment, including air quality, thermal regime, illumination, acoustics/noise, and visual aspects to provide comfortable human physiological and psychological perceptions.

• Optimizing the integration of the new building project within the overall built and urban environment. A truly green/sustainable building should not be thought of or considered in a vacuum, but rather in how it integrates within the overall societal context.

Ultimately, even if a project does not have overtly stated green/sustainable goals, the overall approaches, processes, and concepts presented in this guide provide a design philosophy useful for any project. Using the principles of this guide, an owner or a team member can document the objectives and criteria to include in a project, forming the foundation for a collaborative integrated project delivery approach. This can lower design, construction, and operation costs, resulting in a lower total cost for the life of the project.