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Design Elements
Due to the current market framework, it is often the case that the client that is commissioning a building is often a different client than the one who will operate the building and pay the lifetime of maintenance and operating costs. This dichotomy tends to prevent the designer from specifying increased environmental capital costs in the construction phase because builders often don’t take into account the long-term costs of operating the building. ENVIROMENTAL DESIGN ISSUE Prior to developing a concept design for the building, it is critical to form an appropriate design team and define the direction that the team will take in order to develop a comprehensive design strategy and program. This pre-design stage includes a complete lifecycle analysis of the project. From this collaboration a design approach is established which then allows the designers to optimize each component of the project as well as optimizing all the components in unison. ENVIROMENTAL DESIGN ELEMENT Due to the current market framework, it is often the case that the client that is commissioning a building is often a different client than the one who will operate the building and pay the lifetime of maintenance and operating costs. This dichotomy tends to prevent the designer from specifying increased environmental capital costs in the construction phase because builders often don’t take into account the long-term costs of operating the building. ENVIROMENTAL DESIGN ISSUE Prior to developing a concept design for the building, it is critical to form an appropriate design team and define the direction that the team will take in order to develop a comprehensive design strategy and program. This pre-design stage includes a complete lifecycle analysis of the project. From this collaboration a design approach is established which then allows the designers to optimize each component of the project as well as optimizing all the components in unison. ENVIROMENTAL DESIGN ELEMENT Due to the current market framework, it is often the case that the client that is commissioning a building is often a different client than the one who will operate the building and pay the lifetime of maintenance and operating costs. This dichotomy tends to prevent the designer from specifying increased environmental capital costs in the construction phase because builders often don’t take into account the long-term costs of operating the building. ENVIROMENTAL DESIGN ISSUE A variety of environmental factors must be considered during the design process. Proper consideration by the entire interdisciplinary team during the design stage will ensure efficient, effective architecture that achieves the goals set out during the pre-design stage. ENVIROMENTAL DESIGN ELEMENT Implementing environmental elements during the design stage reduces inefficient operating costs, and future renovation costs. Their successful integration is necessary to achieve optimum building performance. One method of handling the diversity of environmental design considerations during the building design phase is suggested below. ENVIROMENTAL DESIGN ELEMENT design element content ENVIROMENTAL DESIGN ELEMENT design element content ENVIROMENTAL DESIGN ELEMENT The design team must consider the regional and microclimate of the site. Data collected during the site-planning phase can enhance the overall building design and optimize energy performance. ENVIROMENTAL DESIGN ELEMENT The building must be integrated with, rather than stand apart from the surrounding site. It is the design team’s task to integrate the existing landscape and any exterior design elements with the building’s architecture. ENVIROMENTAL DESIGN ELEMENT ENVIROMENTAL DESIGN ELEMENT Consideration of existing infrastructure is important to minimize the costs of a poorly sited building. The design team can take advantage of existing infrastructure to minimize new development and additional equipment capacity. ENVIROMENTAL DESIGN ELEMENT A building's form must be determined by its relationship to the sun and local climate, as much as aesthetics. Building's can take many forms from a hemisphere (igloo) to forms that maximize surface area like the Habitat building in Montreal, Canada built for the World Expo 1967. Each form has advantages and disadvantages. ENVIROMENTAL DESIGN ELEMENT Insulating a building in any climate can have merits. In cold climates, insulation serves to reduce heating costs. In temperate and hot climates, insulation can serve to reduce air conditioning costs. It is often difficult and expensive to retrofit insulation in an existing building so identifying proper amounts at the design stage is critical. Minimization of thermal bridging is also important to achieve maximum benefits of insulation. ENVIROMENTAL DESIGN ISSUE DEFINITION ENVIROMENTAL DESIGN ELEMENT DEFINITION Every opportunity should be made to harness “free” solar energy in the form of heat and light. The design team must also pay particular attention to reducing excessive solar heating especially in temperate and hot climates. ENVIROMENTAL DESIGN ELEMENT Passive Solar Heating: ENVIROMENTAL DESIGN ELEMENT In temperate and hot climates, solar heat infiltrating the building has typically been the most costly thing to mitigate (i.e. air conditioning). However, effective passive solar cooling design can eliminate much of this conventional operating cost with proper building design. Passive solar cooling can reduce or even eliminate the need for air conditioning in homes. At its simplest, passive cooling includes overhangs for south-facing windows, few windows on the west, shade trees, thermal mass and cross ventilation. Some of the same strategies that help to heat a home in the winter also cool it in the summer. Consider preventing excess solar heat from entering the building envelope. A variety of design strategies are listed below. ENVIROMENTAL DESIGN ELEMENT Storing passive solar energy can assist both heating and cooling strategies. Storing heat allows for “free” heating to be used during night hours. Absorbing heat and storing it also decreases the maximum interior temperatures during the hottest times of the day thereby reducing daytime temperature peaks. ENVIROMENTAL DESIGN ELEMENT Passive solar design works by utilizing overhangs to shade a house during the heat of the summer and allow sunlight to penetrate the interior of the house during the winter. PASSIVE SOLAR COOLING OVERHANG DIMENSIONS If you want to heat your building with solar energy, you will need to decide whether you want an "active" or a "passive" system. A passive system does not use a mechanical device to distribute solar heat from a collector. An example of a passive system for space heating is a sunspace or solar greenhouse on the south side of the house. Although passive systems are simpler, they may be impractical for a variety of reasons (for example, building an effective sunspace may not be possible). ENVIROMENTAL DESIGN ELEMENT If you want to heat your building with solar energy, you will need to decide whether you want an "active" or a "passive" system. A passive system does not use a mechanical device to distribute solar heat from a collector. An example of a passive system for space heating is a sunspace or solar greenhouse on the south side of the house. Although passive systems are simpler, they may be impractical for a variety of reasons (for example, building an effective sunspace may not be possible). Active systems employ mechanical and/or electrical means of harnessing and/or using passive solar energy. Harnessing this “free” energy is one of the simplest ways to improve environmental performance and reduce costs of building operation. ENVIROMENTAL DESIGN ELEMENT When building heating is required, temperate and hot climates may be able to rely 100% on solar heating. A variety of design strategies are indicated below. ENVIROMENTAL DESIGN ELEMENT In temperate and hot climates, hot water production can utilize ‘free’ solar energy in whole or in part. At minimum a supplemental solar hot water heating system should be mandatory and a part of every new building design. ENVIROMENTAL DESIGN ISSUE Today, there is increasing evidence that daylight is essential for the health, well being and productivity of individuals. Although productivity is often difficult to quantify, clinical disorders, such as daylight deprivation and seasonal affective disorder (commonly called SAD), are directly linked to a person's lack of light. By carefully designing window specifications for either commercial or residential buildings, architects can contribute to the increased productivity and psychological health of building occupants. ENVIROMENTAL DESIGN ELEMENT Today, there is increasing evidence that daylight is essential for the health, well being and productivity of individuals. Although productivity is often difficult to quantify, clinical disorders, such as daylight deprivation and seasonal affective disorder (commonly called SAD), are directly linked to a person's lack of light. By carefully designing window specifications for either commercial or residential buildings, architects can contribute to the increased productivity and psychological health of building occupants. The design team must balance the need for natural, daylight to penetrate the building envelope, while avoiding excess heating and unwanted morning and evening glare on eastern and western facades. ENVIROMENTAL DESIGN ELEMENT Complete integration of daylighting strategies and systems with other lighting and energy systems is necessary to optimize energy efficiency and permit overall success with daylighting design. ENVIROMENTAL DESIGN ELEMENT design element content ENVIROMENTAL DESIGN ISSUE issue content ENVIROMENTAL DESIGN ELEMENT Any building that will be occupied outside of the daylight hours will require some form of artificial lighting. Efficient design of ancillary lighting combined with effective daylighting integration will ensure maximum energy efficiency. ENVIROMENTAL DESIGN ELEMENT Once the daylighting design is complete, then artificial or supplemental lighting is needed for proper light distribution and off daylight hours. ENVIROMENTAL DESIGN ELEMENT New technology is available and many contemporary lighting fixtures are being replaced by energy efficient fluorescent fixtures and task lighting. Consider retrofitting exit signs to energy efficient fixtures. ENVIROMENTAL DESIGN ELEMENT A source of pollution that is rarely identified or discussed until recently, but present in nearly all hotel developments, light often impacts the access to the night sky and alters nocturnal environments (i.e. turtles reproduction habitat on beaches). Although outdoor lighting may be important for personal and property security, exterior lighting should be controlled to minimize environmental impacts. Exterior lights should be turned off or set on timers to turn off when not needed, especially after guests go to bed. Lights that are required all night should be placed in a manner to achieve their task without excess lighting. ENVIROMENTAL DESIGN ISSUE As one of the largest building operating costs in tropical locales, the HVAC system must be designed with optimum performance in mind. As noted above (See Design Elements: Passive Solar), one of the largest factors determining HVAC systems is the heat transfer performance of the building envelope. A building designed to efficiently deal with outdoor temperatures and passive solar energy may be able to greatly reduce these HVAC operating costs. It is important to reiterate that proper design eliminates a lifetime of high operating expenses and/or costly renovations cost at a future date. ENVIROMENTAL DESIGN ELEMENT As one of the largest building operating costs in tropical locales, the HVAC system must be designed with optimum performance in mind. As noted above (See Design Elements: Passive Solar), one of the largest factors determining HVAC systems is the heat transfer performance of the building envelope. A building designed to efficiently deal with outdoor temperatures and passive solar energy may be able to greatly reduce these HVAC operating costs. It is important to reiterate that proper design eliminates a lifetime of high operating expenses and/or costly renovations cost at a future date.Achieving an efficient HVAC design involves an awareness of all other building systems and the expertise of the entire design team. Integration with all other building systems is priority. ENVIROMENTAL DESIGN ELEMENT Proper HVAC design and minimization of unwanted heat transfer to the interior environment will ensure years of efficient building performance. ENVIROMENTAL DESIGN ELEMENT Control systems allow the designer to automate and integrate building systems. Design the control systems to allow operators to adjust the system components and fine-tune performance. ENVIROMENTAL DESIGN ELEMENT Energy efficient strategies are necessary to optimize air delivery and adequate ventilation. ENVIROMENTAL DESIGN ELEMENT Advances in efficiency and alternative plant technology allow the designer to do more with less. Ensure proper sizing of equipment to avoid additional costs of unnecessary systems. ENVIROMENTAL DESIGN ELEMENT Consider further enhancement options for HVAC systems to improve energy efficiency. ENVIROMENTAL DESIGN ISSUE
Green building techniques will lower energy costs, lower water costs, lower site-clearing costs, lower landfill dumping fees, lower overall material costs, and create fewer employee health problems resulting from poor indoor air quality (Sustainable Building Technical Manual 1996). Environmental design features incorporated early during the design stage will easily pay for themselves in years of operational savings and increased return on investment. It is critical that the entire design team be involved and co-ordinate a holistic, whole building design approach that not only takes full advantage of environmental strategies and technologies, but maximizes the synergies between them as well.
Just as a complete design team was formed prior to selecting a site for the project, the entire design team is required again in order to develop a comprehensive design strategy and program. This pre-design stage includes a complete lifecycle analysis of the project. From this collaboration a design approach is established which then allows the designers to optimize each component of the project as well as optimizing all the components in unison.
Some of the key ingredients the design team needs to consider climatic considerations which will help to determine the building form and orientation. Maximizing thermal efficiency based on the form and orientation.
Pre Design
Some of the key ingredients the design team needs to consider climatic considerations which will help to determine the building form and orientation. Maximizing thermal efficiency based on the form and orientation.
Pre Design/Life Cycle Analysis
Green building techniques will lower energy costs, lower water costs, lower site-clearing costs, lower landfill dumping fees, lower overall material costs, and create fewer employee health problems resulting from poor indoor air quality (Sustainable Building Technical Manual 1996). Environmental design features incorporated early during the design stage will easily pay for themselves in years of operational savings and increased return on investment. It is critical that the entire design team be involved and co-ordinate a holistic, whole building design approach that not only takes full advantage of environmental strategies and technologies, but maximizes the synergies between them as well.
Pre Design
Some of the key ingredients the design team needs to consider climatic considerations which will help to determine the building form and orientation. Maximizing thermal efficiency based on the form and orientation.
Pre Design/Life Cycle Analysis
Green building techniques will lower energy costs, lower water costs, lower site-clearing costs, lower landfill dumping fees, lower overall material costs, and create fewer employee health problems resulting from poor indoor air quality (Sustainable Building Technical Manual 1996). Environmental design features incorporated early during the design stage will easily pay for themselves in years of operational savings and increased return on investment. It is critical that the entire design team be involved and co-ordinate a holistic, whole building design approach that not only takes full advantage of environmental strategies and technologies, but maximizes the synergies between them as well.
Design
The Design Method
Utilize the following method for each design step as a guide:
Confirm environmental design criteria
Develop environmental solutions
Evaluate environmental solutions
Check cost
Integrate systems
Refine environmental solutions
Check cost
Document environmental materials and systems
Verify material test data (i.e. MSDS)
Optimizing Each Element
Optimizing All Elements
Climatic Considerations
Assess the local climate (using typical meteorological-year data) to determine appropriate envelope materials and building designs. In hot-dry climates utilize materials with high thermal mass. In hot-humid climates utilize materials with low thermal mass. In cold climates utilize air tight, well-insulated walls.
Assess the site’s solar geometry. Identify benefits and/or costs of solar gains via roofs, walls, and windows depending on climate.
Building Grounds
Co-ordinate building strategy with landscaping decisions. Involve the landscaping designers and maintenance staff to develop strategies for year round design optimization.
Reduce paved areas to lessen heat buildup around the building that will add to the load on the building envelope. Except in cases of cold climates where exterior heat islands may be useful; decrease paved area and avoid selecting dark colours. Be aware of glare potential on light coloured surfaces.
Human Scale Neighborhoods
Minimize automobile dependence.
Infrastructure
Design the site plan to minimize road length, building footprint, and the actual ground area required for intended improvements. This will reduce length of utility connections.
Use gravity sewer systems wherever possible. Avoid the continuous power consumption that sewer pumps require.
Reuse chemical waste tanks and lines. Inspect existing infrastructure and avoid disposing of adequate tanks and lines.
Aggregate utility corridors when feasible. Utilize existing roads, trenches, and clearings before new land is cleared for trenching.
Building Form and Orientation
Building Form
The igloo is a 'natural' example of the optimum building form. And it is no surprise that the elevated sleeping pad is located directly in the middle of the igloo either. Body heat from the occupants radiates outward and is reflected back toward the centre of the igloo and its occupants due to the hemispherical shape. This maximizes the radiant heat retention for the occupants.
As well, the shape of the igloo minimizes exterior surface area and thus minimizes heat loss from the shell of the igloo. As it turns out the igloo is the perfect design choice by the Inuit of the Arctic. This is also an example of biomimicry, or ethnomimicry.
Figure: Heating energy is dependent upon building form (surface area).
Source: http://www.oikos.com/esb/36/ bldgform.html
The most efficient building form with respect to minimizing heat loss is a hemisphere. The surface area of the sphere is equal to 2 X pi X radius squared. The surface area of the floor is pi X radius squared. This equates to a ratio of 2 (surface area to floor area).
A perfect square's ratio is 4 which means that an igloo has half the surface area of a square (where diameter equals wall length). This relationship continues as the shape becomes more complicated with an ever increasing amount of surface area. Note however, that in a temperate climate where heat loss is not an issue, surface area is not as significant with the exception of the added costs and resources that may be required to construct a building with a complicated form and surface area.
Building Orientation
It is always important to orient a building to optimize the effects of solar radiation. In equatorial and temperate locales, the designer must consider the impacts that direct sun may have on occupants and temperatures in the indoor environment. Large openings that allow for sunrise and sunset light to penetrate the building should be avoided (western and eastern facades) or sun control measures should be considered.
Thermal Efficiency
Determine the building function and amount of equipment that will be used. Determine internal heat gains from occupants and equipment when considering HVAC requirements.
In general, build walls, roofs, and floors of adequate thermal resistance to provide human comfort and energy efficiency. Pay particular attention to roofs as they can receive excessive solar gains in summer and losses in winter.
Consider the reflectivity of the building envelope. In hot climates and when cooling loads are present, review the colour selection and reflectivity of exterior walls.
Prevent moisture buildup within the envelope. Place vapour barrier on the warm side of the wall when space heating is used to prevent moisture from condensing in the wall cavity.
Weatherstrip all doors and place sealing gaskets and latches on all operable windows. Prevent air leakage to avoid convective losses and unwanted infiltration.
Specify construction materials and details that reduce heat transfer. Prevent heat transfer through walls to maintain indoor environments.
Incorporate solar controls on the building exterior to reduce heat gain. Consider solar gains and losses through the roof and all exterior walls.
Consider the use of earth berms to reduce heat transmission and radiant heat loads on the building envelope. Sod roofs and buried exterior walls provide thermal mass that absorbs and controls solar gains.
Passive Solar
Passive solar design refers to the use of the sun's energy for the heating and cooling of living spaces. In this approach, the building itself or some element of it takes advantage of natural energy characteristics in materials and air created by exposure to the sun. Passive systems are simple, have few moving parts, and require minimal maintenance and require no mechanical systems.
Operable windows, thermal mass, and thermal chimneys are common elements found in passive design. Operable windows are simply windows that can be opened. Thermal mass refers to materials such as masonry and water that can store heat energy for extended time. Thermal mass will prevent rapid temperature fluctuations. Thermal chimneys create or reinforce the effect hot air rising to induce air movement for cooling purposes.
Wing walls are vertical exterior wall partitions placed perpendicular to adjoining windows to enhance ventilation through windows.
CONSIDERATIONS
Passive design is practiced throughout the world and has been shown to produce buildings with low energy costs, reduced maintenance, and superior comfort. Most of the literature pertaining to passive solar technology addresses heating concerns. This information is useful and relevant in our area; however, cooling issues, which are equally important in Austin, are less well documented. Key aspects of passive design include appropriate solar orientation, the use of thermal mass, and appropriate ventilation and window placement.
Consideration of high humidity is a key issue in Austin. For example, a basic passive cooling strategy is to permit cooler night air to ventilate a house and cool down the thermal mass (this can be brick, stone, or concrete walls or floors, or large water containers) inside the house. The thermal mass will absorb heat during the day; however, excessive humidity will reduce the cooling effect from the cooler thermal mass. Interior design elements of a home in our region also play a strong role in the effectiveness of passive cooling. For example, carpets, drapes, and fabric-covered furniture will absorb moisture from humid air, forcing the air conditioner to work harder to remove humidity.
As a design approach, passive solar design can take many forms. It can be integrated to greater or lesser degrees in a building. Key considerations regarding passive design are determined by the characteristics of the building site. The most effective designs are based on specific understanding of a building site's wind patterns, terrain, vegetation, solar exposure and other factors often requiring professional architectural services. However, a basic understanding of these issues can have a significant effect on the energy performance of a building.
Solar energy in the form of heat and light is freely available in nearly all locations. In regions where heating is required, design for efficient use of passive solar energy. A building must first be oriented properly (See Sustainable Siting) to take maximum advantage of the solar energy. In locales that require air conditioning, the designer should attempt to minimize solar heat infiltration while allowing for maximum daylighting.
Passive Solar
Passive solar design refers to the use of the sun's energy for the heating and cooling of living spaces. In this approach, the building itself or some element of it takes advantage of natural energy characteristics in materials and air created by exposure to the sun. Passive systems are simple, have few moving parts, and require minimal maintenance and require no mechanical systems.
Operable windows, thermal mass, and thermal chimneys are common elements found in passive design. Operable windows are simply windows that can be opened. Thermal mass refers to materials such as masonry and water that can store heat energy for extended time. Thermal mass will prevent rapid temperature fluctuations. Thermal chimneys create or reinforce the effect hot air rising to induce air movement for cooling purposes.
Wing walls are vertical exterior wall partitions placed perpendicular to adjoining windows to enhance ventilation through windows.
CONSIDERATIONS
Passive design is practiced throughout the world and has been shown to produce buildings with low energy costs, reduced maintenance, and superior comfort. Most of the literature pertaining to passive solar technology addresses heating concerns. This information is useful and relevant in our area; however, cooling issues, which are equally important in Austin, are less well documented. Key aspects of passive design include appropriate solar orientation, the use of thermal mass, and appropriate ventilation and window placement.
Consideration of high humidity is a key issue in Austin. For example, a basic passive cooling strategy is to permit cooler night air to ventilate a house and cool down the thermal mass (this can be brick, stone, or concrete walls or floors, or large water containers) inside the house. The thermal mass will absorb heat during the day; however, excessive humidity will reduce the cooling effect from the cooler thermal mass. Interior design elements of a home in our region also play a strong role in the effectiveness of passive cooling. For example, carpets, drapes, and fabric-covered furniture will absorb moisture from humid air, forcing the air conditioner to work harder to remove humidity.
As a design approach, passive solar design can take many forms. It can be integrated to greater or lesser degrees in a building. Key considerations regarding passive design are determined by the characteristics of the building site. The most effective designs are based on specific understanding of a building site's wind patterns, terrain, vegetation, solar exposure and other factors often requiring professional architectural services. However, a basic understanding of these issues can have a significant effect on the energy performance of a building.
Solar energy in the form of heat and light is freely available in nearly all locations. In regions where heating is required, design for efficient use of passive solar energy. A building must first be oriented properly (See Sustainable Siting) to take maximum advantage of the solar energy. In locales that require air conditioning, the designer should attempt to minimize solar heat infiltration while allowing for maximum daylighting.
Passive Solar Heating
Analyse building thermal-load patterns. Seek strategies that deliver daylight and solar heat when the building requires it.
Integrate passive solar heating with daylight design. They are complimentary strategies.
Design the building’s floor plan to optimize passive solar heating. Windows should face within 15 degrees of true south to take advantage of solar heating.
Identify appropriate locations for exposure to beam sunlight. Shorter occupancy spaces (i.e. atrium, lobby, hallways) can tolerate direct solar gains. Offices where people work for extended periods of time must include measures to disperse direct sunlight and heat (i.e. clerestory windows, light shelves, window tinting).
Avoid glare from low sun angles. Be aware of early morning and late afternoon solar exposure that penetrates deeper into interior spaces. Orient work stations north-south so that partition walls block low angled light.
Locate thermal mass so that it will be illuminated by low winter sun angles. In cold climates, take advantage of low solar angles when space heating is required in winter. The thermal mass will remain in the shade during summer.
Passive Solar Cooling
Design buildings for cooling load avoidance. Utilize appropriate window glazing and shading devices to avoid the need for mechanical cooling.
Choose one or more shading strategies including: fixed shading devices as part of building design (porches, overhangs, extrusions), trees or other vegetation that provide seasonal shading, awnings that can be extended or removed, operable shades or blinds. In general, limit east and west glazings to avoid low solar angle exposure.
Consider other cooling strategies including: taking advantage of natural ventilation, radiative cooling in regions that have significant differences in day and night temperatures, ground coupled cooling, and dehumidification in humid climates.
Thermal Mass
Overhangs
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ENVIROMENTAL DESIGN ISSUE
Active Solar
Active solar heating systems consist of collectors that collect and absorb solar radiation and electric fans or pumps to transfer and distribute the solar heat in a fluid (liquid or air) from the collectors. They may have a storage system to provide heat when the sun is not shining. An active system may be more flexible than a passive system in terms of siting and installation.
Choosing the appropriate solar energy system depends on factors such as the site, design, and heating needs of your house. Local covenants may restrict your options; for example homeowner associations may not allow you to install solar collectors on certain parts of your house. If you are unsure about what type of solar energy system to install, contact a solar energy specialist or engineer. No matter what system you choose, you should learn about it before making a purchase.
Active Solar
Active solar heating systems consist of collectors that collect and absorb solar radiation and electric fans or pumps to transfer and distribute the solar heat in a fluid (liquid or air) from the collectors. They may have a storage system to provide heat when the sun is not shining. An active system may be more flexible than a passive system in terms of siting and installation.
Choosing the appropriate solar energy system depends on factors such as the site, design, and heating needs of your house. Local covenants may restrict your options; for example homeowner associations may not allow you to install solar collectors on certain parts of your house. If you are unsure about what type of solar energy system to install, contact a solar energy specialist or engineer. No matter what system you choose, you should learn about it before making a purchase.
Determine if the climate and building usage is appropriate for an active solar collection system. This will depend on solar availability and planned uses of system.
Determine the financial feasibility of an active solar system. Consider the life
cycle costs of both solar and mechanical systems for up-front costs, operation costs, and maintenance.
Determine an appropriate location for solar collectors on or near the building. Locate solar collectors to maximize exposure to sun (dependent upon latitude and seasonal usage). Avoid shading from vegetation or adjacent structures. Select locations that reduce chances of vandalism. Be conscious of and mediate potential low angle glare from solar panels.
Design collectors to withstand all weather conditions. Specify glass that can withstand severe precipitation (i.e. hail, ice storms) and supporting structures that can withstand extreme wind events.
Design and locate collectors to maintain a clean surface and facilitate cleaning. Design structures that can hold maintenance staff.
Minimize heat losses from the system. Locate collectors near storage systems. Insulate distribution lines.
Avoid over-designing to ensure the longevity of an active solar system. Minimize controls and maintenance. Maximize accessibility to collectors, distribution lines, and storage systems.
Active Solar Heating
Select an active solar heating system and collection medium appropriate for the building’s heating and cooling systems. Water based systems tend to work well with water-based HVAC systems and similarly air-based systems work best with central air distribution HVAC systems.
Evaluate water-based collectors. They offer the ability to transfer heat to water-storage, water-distribution, and air-distribution systems.
Consider air-based systems. Air-based systems avoid the problems of leaks, are more easily maintained, but require more area to collect as much heat.
Consider ventilation air preheat systems. In cold climates, simple solar preheating devices are inexpensive, cost efficient, and easy to maintain.
Active Solar Hot Water
Select the type of solar hot water heater according to climate, cost, and operations and maintenance preferences. Potential systems include: thermosyphon systems which rely on natural convection to distribute collected heat to storage tank located above collectors; direct-circulation systems that pump water or other medium to collectors when solar heating is available; drain-down systems utilize heat exchangers to heat potable water and can be drained during cold seasons when freezing would cause damage; indirect water-heating systems which use a freeze-protected liquid as the collecting medium and heat exchangers; air systems that use air as the storage medium and heat exchangers.
Consider a pre-heat or full-temperature system. Utilizing active solar heating to preheat water can be cost-effective installing a gas or electric backup to boost temperatures of the water to required levels.
For systems using water as a collection medium, consider the following issues: prevent stagnation that can lead to excessive heating and expansion of medium resulting in damage to the system; provide freeze protection when climate warrants it; avoid calcification and corrosion which can reduce flow rates and overall efficiency of system (creates insulating layer); plan for leaks in the system; select a heat-storage system for maximum efficiency and flexibility; minimize pumps and pump energy required.
Daylighting
Through the years, daylight has played an invaluable role in the lighting of buildings. Until the industrial revolution, workers generally spent a large amount of time outdoors or within close proximity to daylight. Not until this century, when electric lights became commonplace, has daylighting been neglected in most buildings.
Allowing natural, “free” daylight to permeate the building’s façade and light interior spaces should be the main goal of the designer. Natural daylight provides a less expensive means of lighting and a healthier (See Indoor Environmental Quality: Lighting Quality) indoor environment. It is important however to consider the impacts of morning and evening low angle sun and daytime heating on the indoor environment.
A recent study indicates that typical people are exposed total daylight levels of greater than 2000 lux for only 90 minutes each day (Savides, 1986). Light exposure is important to the inner time keeping of humans. Through evolution, man has adapted to rhythms such as body temperature to provide him with explicit knowledge of external time (Terman, et al, 1987). The loss of this connection can contribute to fatigue, insomnia, and SAD. Another study of Russian and Czechoslovakian literature indicated that occupants of windowless factories were more subject to headaches, faintness and sickness that similar occupants of factories with windows (Plant, 1970). However, with today's advanced window technology, combined with efficient electric lighting, we can now design cost-effective, healthy buildings, that help to minimize these effects.
Daylight, a full-spectrum light source, most closely matches the visual response that, through evolution, humans have come to compare with all other light. Daylight provides continually changing values, brightness and contrasts to the workplace, allowing the human eye to constantly adjust. This adjustment reduces eye fatigue. The human eye is capable of adjusting to high levels of luminance without producing discomfort (AIA, 1993). However, reflections and brightness need to be controlled in relation to the task or design program.
Windows provide outside contact
Windows are the best means of providing points of contact with the outside environment. Short- and long-range views allow the eye to change focus, provide a connection to the natural world, and to assist in knowing time and weather and provide orientation. The lack of a physical connection is a major source of occupant dissatisfaction in offices. Studies show that many European countries now require that workers be within 27 feet of a window. Switzerland and the Scandinavian countries go a step further. They require that windows also be operable (Loftness, et al, 1993). To offset the problem of overburdening a mechanical system with open windows, automatic sensors are placed within the air diffusers in individual offices. These sense, through a change in air pressure, that a windows is open. They then cut off heat flow to the room so that the heating system is not working against an open window.
With reduced reports of headaches, fatigue and seasonal disorders through increased daylight, worker productivity is bound to increase. Wages and salaries can represent about 95 percent of all costs of a typical office building (Ternoey, et al, 1984). Reduced sickness and absenteeism and the increased performance would, therefore, more than offset any increased initial costs or life cycle costs (Robbins, 1986) associated with providing more workers visual access to windows.
The NMB Bank Headquarters in The Netherlands was designed by architect Ton Alberts of Alberts and Van Huut, to heavily rely on daylight. No desk may be more than 23 feet from a window. Window louvers bounce daylight deep into the space. Inside the bank, wood windows are used to bring the light from one area into another, thereby giving all workers access to daylight, even when they are located in interior spaces.
The bank has seen a significant drop in employee absenteeism, which is attributed to the attractive work environment (Browning, 1992). Each tower of NMB Bank is punctuated by a glass-roofed atrium, allowing a generous use of plants to help bring the outside in.
Enhanced spatial relationships, both within a building and to the outside, are also positive attributes of daylighting. Natural light is the best source of good color rendering, making people and colors look more realistic than they do in electric light. Daylight adds a dimension of expansiveness to spaces and can help to define shapes and tasks. This attribute of daylight is especially critical to the elderly. As the baby boomers age, sensory loss will become a significant issue which designers must face. Common eye problems associated with aging include slower adaptation to light level changes, increased difficulty with glare and requirements for higher illumination levels (Noell, 1992). Contrast between window openings and surrounding wall surfaces can be reduced by proper shading of windows, splaying of window jambs, and proper interior lighting.
When designing a daylit building, the designer must carefully consider the visual tasks to be performed in a space and the needs of the occupants. Glazing choices and the location and design of window openings then are carefully chosen and detailed. With the variety of window types available, fading, overheating and glare can be controlled. Generally, using glass that is clear in color and has a high visible transmittance is desirable. Shading coefficients will vary according to climate, orientation and the thermal needs of the building.
Way Station, a mental health facility in Frederick, Md., uses daylighting to create an aesthetically pleasing and healing environment that helps promote wellness of people with serious mental illness. "Members" and staff of the center comment that the building makes them feel great and that they love that daylight is available in almost every room. The Way Station uses light monitors, tracking daylight collectors, and finely-tuned window strategies to enhance the positive qualities of light. The daylighting techniques are part of an overall strategy that results in an energy cost savings of more than two thirds.
As architects and designers explore the inclusion of daylighting into their designs, the availability of high performance windows with diversity of characteristics to accommodate specific functions will be necessary. Jacob Liberman, Ph.D., states, "When we speak about health, balance and physiological regulation, we are referring to the function of the body's major health keepers; the nervous system and the endocrine system. These major control centers of the body are directly stimulated and regulated by light, to an extent far beyond what modern science, until recently, has been willing to accept."
Design Process
Through the years, daylight has played an invaluable role in the lighting of buildings. Until the industrial revolution, workers generally spent a large amount of time outdoors or within close proximity to daylight. Not until this century, when electric lights became commonplace, has daylighting been neglected in most buildings.
Allowing natural, “free” daylight to permeate the building’s façade and light interior spaces should be the main goal of the designer. Natural daylight provides a less expensive means of lighting and a healthier (See Indoor Environmental Quality: Lighting Quality) indoor environment. It is important however to consider the impacts of morning and evening low angle sun and daytime heating on the indoor environment.
A recent study indicates that typical people are exposed total daylight levels of greater than 2000 lux for only 90 minutes each day (Savides, 1986). Light exposure is important to the inner time keeping of humans. Through evolution, man has adapted to rhythms such as body temperature to provide him with explicit knowledge of external time (Terman, et al, 1987). The loss of this connection can contribute to fatigue, insomnia, and SAD. Another study of Russian and Czechoslovakian literature indicated that occupants of windowless factories were more subject to headaches, faintness and sickness that similar occupants of factories with windows (Plant, 1970). However, with today's advanced window technology, combined with efficient electric lighting, we can now design cost-effective, healthy buildings, that help to minimize these effects.
Daylight, a full-spectrum light source, most closely matches the visual response that, through evolution, humans have come to compare with all other light. Daylight provides continually changing values, brightness and contrasts to the workplace, allowing the human eye to constantly adjust. This adjustment reduces eye fatigue. The human eye is capable of adjusting to high levels of luminance without producing discomfort (AIA, 1993). However, reflections and brightness need to be controlled in relation to the task or design program.
Windows provide outside contact
Windows are the best means of providing points of contact with the outside environment. Short- and long-range views allow the eye to change focus, provide a connection to the natural world, and to assist in knowing time and weather and provide orientation. The lack of a physical connection is a major source of occupant dissatisfaction in offices. Studies show that many European countries now require that workers be within 27 feet of a window. Switzerland and the Scandinavian countries go a step further. They require that windows also be operable (Loftness, et al, 1993). To offset the problem of overburdening a mechanical system with open windows, automatic sensors are placed within the air diffusers in individual offices. These sense, through a change in air pressure, that a windows is open. They then cut off heat flow to the room so that the heating system is not working against an open window.
With reduced reports of headaches, fatigue and seasonal disorders through increased daylight, worker productivity is bound to increase. Wages and salaries can represent about 95 percent of all costs of a typical office building (Ternoey, et al, 1984). Reduced sickness and absenteeism and the increased performance would, therefore, more than offset any increased initial costs or life cycle costs (Robbins, 1986) associated with providing more workers visual access to windows.
The NMB Bank Headquarters in The Netherlands was designed by architect Ton Alberts of Alberts and Van Huut, to heavily rely on daylight. No desk may be more than 23 feet from a window. Window louvers bounce daylight deep into the space. Inside the bank, wood windows are used to bring the light from one area into another, thereby giving all workers access to daylight, even when they are located in interior spaces.
The bank has seen a significant drop in employee absenteeism, which is attributed to the attractive work environment (Browning, 1992). Each tower of NMB Bank is punctuated by a glass-roofed atrium, allowing a generous use of plants to help bring the outside in.
Enhanced spatial relationships, both within a building and to the outside, are also positive attributes of daylighting. Natural light is the best source of good color rendering, making people and colors look more realistic than they do in electric light. Daylight adds a dimension of expansiveness to spaces and can help to define shapes and tasks. This attribute of daylight is especially critical to the elderly. As the baby boomers age, sensory loss will become a significant issue which designers must face. Common eye problems associated with aging include slower adaptation to light level changes, increased difficulty with glare and requirements for higher illumination levels (Noell, 1992). Contrast between window openings and surrounding wall surfaces can be reduced by proper shading of windows, splaying of window jambs, and proper interior lighting.
When designing a daylit building, the designer must carefully consider the visual tasks to be performed in a space and the needs of the occupants. Glazing choices and the location and design of window openings then are carefully chosen and detailed. With the variety of window types available, fading, overheating and glare can be controlled. Generally, using glass that is clear in color and has a high visible transmittance is desirable. Shading coefficients will vary according to climate, orientation and the thermal needs of the building.
Way Station, a mental health facility in Frederick, Md., uses daylighting to create an aesthetically pleasing and healing environment that helps promote wellness of people with serious mental illness. "Members" and staff of the center comment that the building makes them feel great and that they love that daylight is available in almost every room. The Way Station uses light monitors, tracking daylight collectors, and finely-tuned window strategies to enhance the positive qualities of light. The daylighting techniques are part of an overall strategy that results in an energy cost savings of more than two thirds.
As architects and designers explore the inclusion of daylighting into their designs, the availability of high performance windows with diversity of characteristics to accommodate specific functions will be necessary. Jacob Liberman, Ph.D., states, "When we speak about health, balance and physiological regulation, we are referring to the function of the body's major health keepers; the nervous system and the endocrine system. These major control centers of the body are directly stimulated and regulated by light, to an extent far beyond what modern science, until recently, has been willing to accept."
Establish daylighting performance objectives and requirements. These objectives may be developed during the pre-design phase (See 2.1 – Design Elements: Pre-Design).
Analyze lighting performance needs using the following procedure: perform a solar path analysis for the site, perform preliminary aperture-optimization strategies, determine and design illumination levels for various programs, perform a preliminary life-cycle cost-benefit analysis.
Establish basic daylighting parameters as part of the building design including: location, shape, and orientation of building; fenestration design objectives; energy-efficient artificial illumination systems; preliminary life cycle cost analysis of daylighting systems; optimal effective aperture of toplighting strategies; lighting control strategies.
Specify details for lighting systems and products including: glazing materials, finishes, shading systems location and type, control systems.
Confirm that specified practices and materials are installed properly. Monitor direct sunlight penetration. Observe that seals are correctly installed on all skylights. Observe final calibration of lighting control systems.
Ensure that the building’s daylighting features are in place and maintained for optimum performance including: control systems, maintenance schedule, and education for occupants.
Daylighting Systems
Avoid direct sunlight and excessive brightness on critical task areas. Evenly distribute light in interior spaces (i.e. light shelves, clerestories). Avoid placing workstations and computer screens adjacent to windows.
Bring the daylight in at a high location. Utilize windows, skylights, roof monitors, and clerestories. Consider colour and reflectance of ceiling members.
Diffuse and distribute the daylight using: vegetation, draperies, screens, translucent shades, light shelves, and light scattering glazing.
Bounce the daylight off of surrounding surfaces. Use light shelves, louvers, blinds, and vertical baffles to distribute light.
Integrate daylight with other building systems and strategies.
Maintain a favourable room aspect ratio – the ratio of ceiling height and window height to depth of room from window. See diagram to the right.
Establish an appropriate building footprint. The ideal building depth is limited by the dimension required for a double-loaded corridor (exterior window/wall-daylit room-corridor-daylit room-exterior window/wall).
Specify the appropriate room reflectivity (surface reflectance).
Rely on clerestories in addition to windows. They allow light to penetrate deeper into a space.
Consider a sawtooth roof form to provide uniform illumination over a larger area.
Design roof monitors and skylights to provide lighting of interior spaces. Skylights are efficient in that they usually have 180-degree view of the sky.
Use sloped or curved ceiling planes. Ceiling planes are the simplest mechanism of distributing light in a space.
Optimize overhangs based on window height and latitude (solar altitude). Consider seasonal benefits and drawbacks with permanent overhangs.
Incorporate light shelves with windows where appropriate.
Employ baffles, louvers, and reflectors as appropriate in conjunction with any of the above-mentioned strategies for solar control.
Integrate daylighting with luminous ceiling systems.
Consider solar shade and awning systems.
Consider optical venetian blind systems.
Consider advanced light-shelf systems. See figure to the right.
Consider advanced systems such as active concentrating heliostats, passive collimating systems, and high-performance optical skylights.
Consider light-pipe distribution. They are effective at delivering natural daylight to interior spaces without exterior partition walls.
Consider spectrally selective glazings, which filter certain wavelengths (i.e. infrared) allowing for maximum daylighting while maintaining energy efficiency.
Consider switchable glazings for differing seasonal conditions. Photochromic glass darkens at predetermined intensity levels. Thermochromic glass becomes translucent at predetermined temperatures. Electrochromic glass darkens when an electrical current is applied. Liquid crystals become clear when an electrical current is applied and are translucent otherwise.
Fenestration and Form
Artificial Lighting
Artificial Lighting
Integrate lighting controls to respond to available daylight.
Ensure good control-system design.
Integrate daylight controls with other control strategies.
Design Process
Include the entire design team in the design of building massing, orientation, and envelope to achieve greater daylighting contribution.
Incorporate the most energy-efficient technology for lamps, fixtures, and control equipment.
Consider all lighting functions including the ambient system, task lights, emergency and 24-hour lighting, exterior lights, exit lights, and public-area lights.
Use sophisticated design analysis, including computer simulation, for system design.
Consider using the guidelines of the Illuminating Engineering Society (IES). IES guidelines are helpful for designing outdoor lighting.
Design for specific visual tasks. Consider lower ambient lighting levels in exchange for more directed task lighting.
Consider task-lighting systems that reduce general overhead light levels.
Match the quality of light to the visual task lighting requirement. Quality is more important than quantity.
Improve lighting design and energy efficiency by performing several key activities in the early phases of architectural space planning. Co-ordinate the lighting plan with furniture layout. Design for daylighting to be available in hallways, lounges, and areas of recreation. Group occupants with similar tasks together so that unoccupied areas require less lighting.
Improve room-cavity optics. Utilize high reflectance walls and light colours to enhance daylighting.
Provide effective lighting control. Use sensors that automatically adjust artificial lighting with daylighting available. Allow occupants to adjust lighting levels.
Consider improved task lighting products.
Convert existing light fixtures. In many cases, more efficient fixtures are available.
Light Fixtures
Specify efficient lamps for the intended use. Select T8 fluorescent lamps; compact fluorescent lamps; lower wattage, high colour rendering lamps; compact reflector HID lamps; halogen lamps with infrared reflectors; sulphur bulbs.
Use efficient exit signs. Exit signs are available that use little or no electricity.
Use electronic ballasts. They are 10-20% more efficient than most magnetic-coil ballasts.
Improve optical control. Improve task lighting while lowering overall ambient lighting levels.
Light Pollution
Direct lighting to specific tasks. Avoid lighting areas that do not require it.
Use lighting controls to turn lights off when not needed. Timers and motion sensors increase energy efficiency.
Heating, Ventilation, and Air Conditioning (HVAC)
PreDesign
Develop a conceptual model that illustrates projected energy use and sources. Be sure the entire design team has input at this stage.
Use the following approach in performing the analysis of different systems. Explore passive solar strategies and non-energy intensive HVAC and lighting opportunities. Consider the building envelope when examining HVAC strategies. Consider the building orientation and footprint. Consider thermal mass appropriately placed. Optimize energy benefits of glazing through appropriate selection, placing, and design of the building façade. Consider daylighting strategies to reduce HVAC requirements. Consider shading devices. Control unwanted infiltration. Consider increased insulation levels. Reduce internal heat gains.
Design the HVAC system and consider potential options for energy efficiency.
Improve control systems by using computer software programs and sensors to operate building in accordance with occupancy patterns.
Develop accurate pricing. Taking into account life cycle costing.
Design Process
Define the project design criteria. They should reflect the building’s use, occupancy patterns, density, passive solar opportunities, office equipment, lighting levels, comfort ranges, and space specific needs.
Use advanced design methods. Utilize up-to-date software and avoid oversizing systems.
Design for part-load efficiency. Specify equipment that remains efficient over a wide range of operating conditions.
Optimize system efficiency. Give priority to overall system efficiency rather than individual components.
Design for flexibility. Consider a change in occupancy or new technology and how easy the system can be reconfigured.
Control Systems
Design a building management control system.
Train building engineers to use the control system for greater comfort and efficiency.
Integrate the operation of all components and install a centralized computer interface throughout the project.
Consider that the HVAC control systems include the following functions: comfort control (temperature, humidity), scheduled operation, sequenced modes of operation, alarms and system reporting, lighting and daylighting integration, maintenance management, indoor air quality management, remote monitoring and adjustment, commissioning flexibility.
Air Delivery Systems
Use variable air volume systems. These systems remain efficient during partial loading.
Avoid reheating for zone temperature control. Consider dedicated perimeter heating and room return air for heating to minimize outdoor-air reheat penalty.
Reduce duct system pressure losses. Due to proportion of energy used to distribute air using fans, efficient duct design is integral.
Reduce duct leakage and thermal losses by specifying low-leakage sealing methods and good insulation.
Consider proper air distribution to deliver conditioned air to the occupied space. Select appropriate diffusers for the task.
Use low face velocity coils and filters. Reducing velocity across impediments reduces energy losses.
Use cold air systems. This reduces airflow requirements and fan energy usage.
Design equipment and ductwork with smooth internal surfaces. This minimizes friction losses and reduces dust and microbial buildup.
Central Equipment
Evaluate chiller selection. Open-drive compressors save energy by not directing compressor motor heat into refrigerant flow. Consider evaporative cooling equipment.
Evaluate a multiple chiller system with units of varying size. Or a chiller system with variable-speed drives to maintain efficiency through a range of operating loads.
Consider desiccant dehumidification in cases of significant latent load or in humid environments.
Consider absorption cooling that changes energy source from electricity to less expensive gas.
Consider thermal energy storage to effectively manage diurnal and seasonal loads.
Evaluate hydronic-pumping systems.
Evaluate heat exchangers. Select heat exchangers with low approach temperatures and reduced pressure drops.
Consider other heating system equipment and enhancements including: using condensing boilers, matching output temperatures to the load, using temperature reset strategies, selecting equipment that maintains efficiency under partial loading.
Evaluate heat recovery options. Especially in cases when heating and cooling loads occur simultaneously.
Efficiency Enhancement Options with HVAC
Consider additional improvements to energy efficiency including: higher efficiency motors, variable-speed drives, mechanical drive efficiency, direct digital control systems, advanced control strategies (i.e. system optimization, dynamic system control, integrated lighting and HVAC control, and variable-air
volume (VAV) box airflow tracking).
Undertake independent system testing, adjustment, and balancing to improve efficiencies and comfort.