Abstract
Buildings are responsible for 40% of global energy use and produce over a third of global greenhouse gas emissions. These impacts are being acknowledged and addressed in specialist building design techniques and technologies that aim to reduce the environmental impacts of buildings. These techniques and technologies can be referred to collectively as green building technologies. This chapter describes green building technologies and shows why they are vital in addressing climate change and reducing the negative environmental impacts associated with built environments. A structured approach is presented which can be applied to identify and integrate green building technologies into new and existing buildings. By combining global implications with technical detail, the chapter provides a valuable guide to green building technologies and their role in supporting a transition to a more sustainable future.
TopIntroduction
Green building technologies describe technologies and techniques used in built environments to minimize environmental impacts, such as climate change while ensuring that buildings are able to accommodate the functions they have been designed for, and are comfortable and productive to live and work in.
Given the onset of climate change, green building technologies must also now ensure that built environments can continue to support their required functions and maintain comfortable conditions under projected future climatic conditions
Therefore, in order to understand green technologies in buildings, it important to understand the relationship between built environments and the natural environment. In particular, it is important to ascertain the role that technology plays in this relationship, as this has the potential to increase impacts and environmental damage or to avoid damage and create beneficial impacts.
This understanding can be used to identify and develop, ‘green technologies’ which can be applied in built environments to reduce environmental impacts. It is also important in understanding how these technologies can be adopted and integrated within a larger built environment scheme and processes.
As the application and integration of these technologies in built environments can be complex, it is also valuable to define structured processes which can be used to integrate technologies effectively into the planning, design, construction and management of built environments.
This chapter on green building technologies therefore is structured in the following parts:
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Climate Change: This describes climate change and the role green building technologies play in both climate change mitigation and adaptation.
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Occupant Comfort and Productivity: This describes the nature of occupant comfort and productivity and how green building technologies can be used to enhance this in buildings.
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Green Building Technologies: This describes technologies and techniques in buildings which can be applied to achieve occupant comfort and productivity in buildings while minimizing environmental impacts. It focusses on energy efficient technologies and passive design techniques related to occupant comfort and productivity.
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Integrating green building technologies: This section describes a structured approach that can be used to support the integration of green technologies in buildings. It focusses methodologies that support the selection and application of technologies that is responsive not only to global environmental concerns but also to local environmental, social and economic issues.
TopClimate Change
Climate change has been identified as one of the most significant global issues (Hamin and Gurran, 2009). Climate change describes changes to the climate associated with human activity (Intergovernmental Panel on Climate Change, 2015). These changes are also referred to as global warming and are caused by the accumulation of greenhouse gasses in the upper atmosphere. Gases such as carbon dioxide, methane, nitrous oxide and chlorofluorocarbons are known as greenhouse gases because they trap heat from the sun and reduce the extent to which this heat from the sun is reradiated into space from the earth. Increasing the quantities of these gases results in a stronger ‘greenhouse effect’ as more heat is retained, leading to higher global temperatures.
Increases in carbon dioxide levels in the atmosphere, therefore, has a direct impact on global warming and climate change. Rapid increases in carbon dioxide are attributed to increases in the burning of fossil fuels and a loss in vegetation that sequestrates carbon dioxide. Both of these activities are linked to built environments. Built environments have a physical footprint and new urban areas and cities result in losses in farmland and natural vegetation, and therefore sequestration capacity. Built environments also consume energy in construction and operation from power stations that burn fossil fuels.
Human activities have now resulted in levels of carbon dioxide in the atmosphere increasing from 280 parts per million to 400 parts per million. The International Panel on Climate Change (IPCC) warns that this trend is unsustainable and that further increases will very severe consequences, as follows:
Key Terms in this Chapter
Glazing: Windows, glazed doors or other transparent and translucent elements including their frames (such as glass bricks, glazed doors, etc.) located in the building fabric.
Ventilation: The process of supplying air to or removing air from a space for the purpose of controlling air contaminant levels, humidity, or temperature within the space.
Solar Heat Gain Coefficient (SHGC): A measure of the amount of solar radiation (heat) passing through the entire window, including the frame. SHGC is expressed as a number between 0 and 1.0. The lower the SHGC the better.
Emissions: Are substances released into the air and are measured by their concentrations, or parts per million, in the atmosphere.
Climate Change: Describes a change in the state of the climate that persists for an extended period. This is identified by changes to the mean, for instance, mean temperatures over a long period.
Watt (W): A unit for power (P) or the rate at which work is performed.
Envelope: The external elements of the building such as the walls, windows, and roofs.
Climate: Climate describes the average and variations of weather in a region over long periods of time.
Occupants: People who occupy the building on a normal working day.
Thermal Mass: A term to describe the ability of building materials to store heat.
R-Value: Used in the construction industry to denote the measurement of the thermal resistance of a material.
Mitigation: Mitigation involves taking actions to reduce greenhouse gas emissions and to enhance sinks, such as carbon sequestration, in order to reduce the extent of global warming.
Ventilation Opening: An opening in the external wall, floor, or roof of a building designed to allow air movement into or out of the building by naturally-driven ventilation through a permanent opening, an openable part of a window, a door, or other device which can be held open.
Adaptation: Adaptation refers to adjustments to respond to climate change.
Air Conditioning: A mechanical system installed in a building to control the temperature and humidity of the air by heating or cooling.
Shading Coefficient: A measure of the solar gain performance of windows. It is the ratio of the solar energy transmitted and convected by the window to the solar energy transmitted and convected by clear 3 mm glass.
Natural Ventilation: Ventilation provided by thermal, wind, or diffusion effects through doors windows or other intentional openings in the building.
Greenhouse Gas: The main greenhouse gases are water vapor (H2O), carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O), hydrofluorocarbons (HFCs), perfluorocarbons (PFCs), and sulfur hexafluoride (SF6).
Global Warming: Global warming is the warming trend that the earth has experienced over the past century.
HVAC: Heating, ventilation, and air conditioning.
Thermal Resistance: The resistance to heat transfer across a material. Thermal resistance is measured as an R-value. The higher the R-value the better the ability of the material to resist heat flow.
Mixed-Mode Ventilation: A hybrid solution where natural ventilation systems are assisted by mechanical systems to achieve improved ventilation and comfort criteria. Complementary and zone-mixed strategies are most commonly adopted.
RCPs: Representative concentration pathways are defined according to their contribution to atmospheric radiative forcing in the year 2100 relative to pre-industrial values. An RCP 8.5, therefore, represents the addition to the earth’s radiation budget as a result of an increase in GHGs of +8.5 W/m 2 .
Renewable Energy: Is energy from sources that will renew themselves within our lifetime. Renewable energy sources include wind, sun, water, biomass (vegetation), and geothermal heat.