Lecture 8 Thermal Inertia & Passive Design Techniques PDF

Prince Mohammad bin Fahd University College of Architecture and Design Department of Interior Design ARCH 2341 Principles of Design w/ Climate Fall 2024/2025 Lecture #8 Thermal Inertia Instructor: Lujain Khalid Al-Eidi...

Prince Mohammad bin Fahd University College of Architecture and Design Department of Interior Design ARCH 2341 Principles of Design w/ Climate Fall 2024/2025 Lecture #8 Thermal Inertia Instructor: Lujain Khalid Al-Eidi Key considerations in designing for THERMAL COMFORT include: 1- Solar gain & Air Movement Through its overall shape, orientation, number and size of windows and the ability of surfaces to reflect heat, the building envelope can control how much heat from the sun (solar gain) is allowed to enter into the building. 2- Thermal inertia The materials used to construct the building (the choice of brick, stone or wood, for example) have an impact on how quickly changes in weather conditions are felt. 3- Insulation Insulating the building envelope and using thermally efficient windows reduces heat loss in winter and conduction heat gains in summer. 4-Air tightness and ventilation An airtight envelope, together with natural or mechanical ventilation, can control the indoor thermal environment by managing the air exchanges with the outside. The Three Tier Approach to Sustainable design  The Three Tier Approach to Sustainable design The sustainable design of heating, cooling, and lighting buildings can be more easily accomplished by understanding the logic of Active the Three Tier Approach to Sustainable design. The Tier One and Two are the domain of the architect, and in these two levels can reduce the energy consumption of building as much as 80 %. Remember Passive solar buildings can look like other buildings but cost less to run and are more comfortable to live in. Basic Building Design The Architecture Approach to Sustainable Design Tier 1 Basic (General) Building Design Building exterior Site (Building Envelope) Building (interior) 1. Location 1. Building Form 1. Windows: 2. Site Design 2. Building Orientation Orientation Size 3. Landscaping 3. Exterior Color Glazing Type 4. Exterior Shading 4. Insulation Insulation 5. Construction Materials Shading 6. Air Tightness 2. Efficient Lighting 3. Efficient Appliances The Architecture Approach to Sustainable Design Tier 1 Basic (General) Building Design Views and Daylighting 1. Building form and depth establishes opportunities for views to the outside. Limiting the depth of the building floor plate so the deepest workstation is less than 7.60 meters away from the perimeter. 2. It lays the foundation for access to daylight. Limiting the depth of the building so the deepest workstation is less than twice the height of the window from the perimeter can provide enormous opportunities for natural light penetration. The Architecture Approach to Sustainable Design Tier 1 Basic (General) Building Design Views and Daylighting 1. 2- Building orientation and external shading for windows can ensure access to glare-free, useful daylight. Providing external shading ensures that glazing will be shaded from direct sun, or glare, allowing internal shades to stay up and preserve comfortable access to natural light and views. 2. More glazing is not more daylight The Architecture Approach to Sustainable Design Tier 1 Basic (General) Building Design Thermal comfort 1. 1- Control solar gains along perimeter spaces with external shading devices to limit the temperature delta through the depth of the room. 2. 2- Providing thermally variable spaces lets users elect their workspace based on thermal preference. 3. 3- Individual or personal thermal controls can enhance how thermal comfort is perceived. These controls can allow a person to control their comfort set-point. Desk fans or a user-controlled thermal chair gives an individual control over the immediate thermal environment without affecting the environment and comfort of other occupants.. The Architecture Approach to Sustainable Design Tier 2 Passive system Heating Cooling Lighting Direct heat gain 1. Comfort Ventilation 1. Light Shelves through: 2. Night Flush Cooling 2. Clerestories 3. Earth Coupling 1. Trombe Wall 4. Cool Tower 3. Light tubes 2. Sunspace (solarium). The Architecture Approach to Sustainable Design Tier 2 Passive system Heating Trombe walls are a type of technology that can be Direct heat gain installed in homes to passively heat the building. which through: reduces the need to heat the building using traditional 1. Trombe Wall methods such as furnaces or other space heaters, reducing the amount of energy used to heat the home. 2. Sunspace (solarium). These walls are built of some dark-colored material - sometimes concrete - that is built facing the Sun so that the solar radiation is incident on this wall. This wall is then covered with an exterior glazing, with a small amount of air between the wall and the glazing. This glazing works to trap the sunlight. In the Northern hemisphere these walls are south facing. The Architecture Approach to Sustainable Design Tier 2 Passive system Heating Direct heat gain Trombe Wall through: 1. Trombe Wall 2. Sunspace (solarium). The Architecture Approach to Sustainable Design Tier 2 Passive system Heating: Sunspace (solarium). Also known as solar rooms, solars; A room which is designed to collect sunlight and heat through direct and indirect gain systems. What about cooling? The Architecture Approach to Sustainable Design Tier 2 Passive system Heating Cooling Direct 1. heat Ventilation Comfort gain Comfort ventilation: 2. Night Flush Cooling through: An intake and exhaust air ventilation 3. 1. Earth TrombeCoupling Wall system including highly efficient heat 4. 2. Cool Tower(solarium). Sunspace recovery based on a particularly comfortable and energy-saving design. The Architecture Approach to Sustainable Design Tier 2 Passive system The Architecture Approach to Sustainable Design Tier 2 Passive system Any mechanism that makes use of the natural effect of the earth's constant ground temperature. between about 3 and 12 metres below ground surface, the temperature of the earth remains relatively constant throughout the year, so in summer it is cooler than the outside temperature and in winter it is warmer than the outside temperature. The effect lessens gradually as depth decreases. The Architecture Approach to Sustainable Design Tier 2 Passive system https://www.youtube.com/watch?v=sWJCWDpY9is The Architecture Approach to Sustainable Design Tier 2 Passive system a passive architectural device used to reflect natural daylight into a building. 'Bouncing' sunlight off a horizontal surface distributes it more evenly and deeply within a space, whereas direct sunlight can cause glare near an opening, whilst leaving dark areas further in. The Architecture Approach to Sustainable Design Tier 2 Passive system The Architecture Approach to Sustainable Design Tier 2 Passive system External views The provision of long distance views and a visual connection to the outdoors commonly increases wellbeing for building occupants. In office buildings, views can reduce eyestrain for computer workers; In residential buildings, views provide a sense of connectivity. Architects needs to carefully balance between sufficient external views and limiting the overlooking into neighboring properties. The Architecture Approach to Sustainable Design Tier 2 Passive system Internal noise levels Excessive noise generated by neighbors, traffic and hard surfaces that reflect internal sounds (echo) can impact occupant’s amenity and employee’s productivity. In order to ensure comfortable noise levels, architect should consider inserting acoustic insulation to internal and external walls, double glazing to windows, landscaping that buffers traffic noise and a good balance of internal hard and soft finishes. The Architecture Approach to Sustainable Design Tier 2 Passive system Daylight Good access to natural light is essential to occupant wellbeing and employee performance. Daylight is vital for body functions, gives us a sense of time and place and connects us to our environment. Daylight is the combination of direct and indirect (reflected) sunlight. Therefore, on a cloudy day; south facing windows will receive just as much daylight as north facing windows. High level windows will throw daylight deep into rooms, that’s why they are particularly useful for deep floor plans.  Theory and perception of light Daylighting analysis and design Passive Daylighting Strategies Shading devices and techniques Case study  A. FIXED EXTERIOR SHADING DEVICES 4- SHADING MOVABLE EXTERIOR DEVICES AND B. SHADING DEVICES TECHNIQUES C. INTERIOR SHADING DEVICES  FIXED EXTERIOR SHADING DEVICES 1.External Shading Systems Splay walls can reduce the contrast between windows and walls. Windows create less glare when the adjacent walls are not dark in comparison to the window. Splayed or rounded edges create a transition of brightness that is more comfortable to the eye.  2.Eaves The simplest and least expensive shading method for northern elevations and are all that is required on most single story building. As a rule of thumb, eaves width should be 45% of the height from the window sill to the bottom of the eaves. Eaves width Window height 450mm 900–1200mm 600mm 1200–1350mm 900mm 1350–2100mm 1200mm 2100–2700mm 3.Light shelves A horizontal overhang with a high reflectance upper surface is placed above eye-level to reflect daylight onto a light colored ceiling and deeper into a space. Light shelves must be much longer on east and west windows than on south windows, and they are not needed at all on north windows.  Light shelves are placed above eye A second light shelf on the interior is Although temptingly convenient, having level to prevent glare from the top of more effective in collecting daylight and light shelves only on the indoor side of the shelf. In this position, they also act throwing it farther into a room than windows misses the opportunity for the as overhangs for the view windows using louvers to control the sunlight light shelves to also shade the view underneath. entering through the upper daylight windows. glazing. It is best to have them both outdoors and indoors. 4.Fixed - Louvers Fixed horizontal louvres set to the noon mid- winter sun angle and spaced correctly allow winter heating and summer shading in locations with cooler winters. As a rule of thumb, the spacing (S) between fixed horizontal louvres should be 75% of their width (W). The louvres should be as thin as possible to avoid blocking out the winter sun. The Ventura Coastal Corporation’s administration building in Ventura, California Case study The Ventura Coastal Corporation’s administration building in Ventura, California, uses light shelves to daylight the building, sloped ceilings, clerestories, north-facing windows, and open planning all help to illuminate the Ventura Coastal Corporation’s administration building during the day.  MOVABLE EXTERIOR SHADING DEVICES Use movable shades. A dynamic environment calls for a dynamic response. Adjustable shading allows the user to choose the desired level of shade.  Exterior roller shades made of rigid slats move in a vertical plane, and some can also project out like an awning. Louvers in a vertical or horizontal plane painted a light color are beneficial because they block direct The automated fabric roller shades on sunlight yet reflect diffused sunlight the exterior of east and west windows are guided by vertical support cables which keeps the shades from swaying in the wind.  Movable - Louvers This employment of adjustable louvers is in the Chiswick Business Park in London, UK. Adjustable exterior louvers are effective Exterior venetian blinds, which can be sun-control devices, drawn up out of the way. but they will always block the view somewhat (disadvantage)  INTERIOR SHADING Interior shading devices for solar control. DEVICES Interior devices, such as curtains, roller shades, venetian blinds, and shutters, are also important. Interior devices are often less expensive than external shading devices. The interior shading devices are less effective at reducing solar heat gain than external shading because the solar radiation has already come through the glass. Interior shading devices that contribute to quality daylighting. Top light: Skylights Most are passive, but can be active Have a clear or diffusing medium (usually acrylic) Allows daylight to penetrate an opening in the roof Double layer of material, for increased insulation. Skylight catch direct overhead light and transmit it in the narrow area below.  Advantages ad disadvantages Advantages of Skylights: Disadvantages of Skylights: They allow fairly uniform The intensity of light is greater in the summer than in the winter—just the illumination over very large opposite of what we want. interior areas, while It is difficult to shade horizontal glazing. daylighting from windows is limited to about a 15 ft (4.5 m) For these two reasons, it is usually more appropriate to use vertical glazing on the roof perimeter zone. in the form of clerestory windows, monitors, or sawtooth arrangements. Top light: Clerestories & Monitor Clerestories, monitors, and light scoops are by definition all raised above the main roof in order to bring light to the center of a space. The word “monitor” is ordinarily used when the windows face more than one direction and are operable The vertical or near-vertical glazing of clerestories has the characteristics of windows rather than skylights. When they face south, clerestories have the desirable effect of collecting more sunlight in the winter than in the summer.  Guidelines for Clerestories 1. Orientation. Face openings south to get the most winter solar heating and good lighting all year. 2. Reflective roof. Use a high- reflectance white roof to reflect more light through the clerestory glazing. 3. Reflecting light off interior walls. Walls can act as large, low brightness diffusers. A well lit wall will appear to recede, thereby making the room seem larger and more cheerful than it actually is.  Channels light from a lens at roof to a lens at ceiling plane. Top light: Solar Use a highly tube. reflectivetubes film on the interior of a Tend to be much smaller than a typical skylight Still deliver sufficient daylight for dimming of electric lighting. Dr. David Suzuki Public School Case study  Skylights - Sun tracker active daylighting system dome units are installed at roof areas above the Kindergarten Rooms. They are skylights with clear acrylic domes with UV protection, with a reflective mirror and controller that has the ability to accurately calculate the sun's position. Clerestory Windows - Are high, vertically placed windows which allow light to shine onto interior light colored wall surfaces, which are placed so as to reflect indirect light to interior areas.  Window System - Large windows are provided in an energy enhanced thermally broken aluminum curtainwall system with both fixed and operable hopper windows. A visible light transmittance value of 59% significantly improved the amount of captured daylight into the building with improved transparency. Large windows located 16" above finished floor incorporate four operable windows, which provide additional natural light, ventilation and view.  Light Shelves - Are reflective horizontal suspended aluminum shelf ledges located at a high level on the interior side of the exterior window system that reflects sunlight into the classrooms indirectly reflecting light to the ceiling. They reduce glare into the room generally associated with direct sunlight through the window and drive light deeper into interior spaces and away from the floor.  Light Tubes - Solar light tubes are provided in the gymnasium, stairwells and specialty interior areas. They consist of a metal tube through the roof with an outer acrylic clear glazing dome with variable prism optics, moulded into the outer dome to capture low angle sunlight and limit high angle sunlight. Windows Performance Glazing materials One of the best ways to measure the effect of windows on building energy use is to know and understand the glass characteristics which are the U-factor, SHGC, and VT rating. The National Fenestration Rating Council (NFRC) is non-profit organization that administers the only uniform, independent rating and labeling system for energy performance of windows, doors, and skylight. The U-value The U-value measures how well a product prevents heat from escaping a building. U-value ratings generally fall between 0.20 and 1.20. The smaller the U-value, the less heat is transmitted. The U-value is particularly important in cold climates. The U-value, also known as the U- factor. Solar Heat Gain Coefficient (SHGC) Solar Heat Gain Coefficient (SHGC) measures how well a windows blocks heat from sunlight. The SHGC is the fraction of the heat from the sun that enters through a window. SHGC is expressed as a number between 0 and 1. Windows for colder climates should have SHGCs greater than 0.7, while warmer climates should have lower coefficients. The lower a window’s SHGC, the less solar energy passes through the window glazing and frame. The higher a window’s SHGC, the more solar energy passes through the window glazing and frame. Visible Transmittance (VT) Visible Transmittance (VT) measure how much light comes through a product. VT is expressed as a number between 0 and 1. Heavily tinted products have a relatively low VT. Increasing daylight penetration The higher the window head, the deeper the daylight Other ways light can be allowed to penetrate into the building interior include: will penetrate into the interior. installing full-height windows with the head as A window will produce useful illumination to a depth of high as possible. approximately 1.5 -2 times the window head height. using roof-lights for top lighting. installing light shelves. Therefore, increasing the height of the window head can installing clerestory windows. increase the depth of light penetration up to two times using glazed internal walls or borrowed lights. installing tube light or more. designing open plan spaces. designing all spaces have access to an external wall. arranging spaces so natural lighting comes from two or more directions. Improving interior lighting levels Use reflective finishes such as light colors, gloss finishes and mirrors to increase the penetration of natural light into the interior. Reflectance values of light colors increase daylight penetration up 80% from ceilings, 50–70% from walls and 20–40% from floors. The reflectance value for white paint is approximately 75% when new but drops off as it discolors with age. Improving interior lighting levels If one large opening is provided instead of several small ones, a more The higher the window is desirable distribution of light is placed in the wall, the deeper secured. Dark areas between is the penetration of light. openings are eliminated. Windows in more than one A horizontal window gives a wall give more effective wider spread of light than a daylighting than windows in vertical window of the same just one wall. area. Architects often use a combination of these strategies to maximize natural light in a space. Joel & Dena Gambord Business and Information Technology Building California State University Monterey Bay Case study  HMC Architects used three passive daylighting strategies. 1. The building features a central atrium that connects the interior and exterior spaces. We lined the atrium with large skylights and clerestories to draw daylight in. We also installed floor-to-ceiling windows on interior walls. Light enters through the skylights and eventually reflects through the interior windows, lighting the rooms inside. 2. We maximized exterior windows on the north and south orientation. 3. On the east and west orientation, we created a custom external shading system. This prevents glare and unwanted solar heat gain while still allowing plenty of diffuse light into the space. the design underscores the site’s natural setting and helps to create a sense of place for the university. The landscape draws from local influences of beach, ocean, tide, and wind; these forces form sand dunes, which are the site’s iconic landscape feature. The building Certified LEED Gold, It is the first building in university to incorporate radiant heating and cooling combined with natural ventilation and dedicated outside air. Kroon Hall Yale University Case Study Reading Room Kroon Hall at Yale A narrow, curved-roof rectangle built of stone, concrete, steel, and glass, Kroon is set between two existing science buildings, forming two new grassy courtyards, and taking the place of an aging power plant on a brownfield site. For example, the building’s long and thin shape was designed to maximize southern exposure for passive warmth and natural lighting throughout the interior while serving as the ideal orientation for both photovoltaic panels on the roof and hot- water solar units embedded in the wall. Project Team used passive daylighting strategies. Overhead skylights use photovoltaic panels to capture solar power Highly Insulated Façade with High Performance Windows & External Shading. A modernist blend of a cathedral nave and a Connecticut barn, the building is long and thin, sited to admit heat (from above and below ground), daylight, and air – as well as to create outdoor spaces for practical and aesthetic purposes. Most used areas get maximum sun exposure: Top floors have reading room, classrooms and a café/ bottom floors have conference rooms. 1. PVs on roof, 2. PVs embedded in glass, 3. laminated roof beams, 4. environmental center, 5. rainwater collection, 6. operable windows, 7. local sandstone walls, 8. concrete structural system, 9. colonnade, and 10. geothermal system. The building minimize the energy requirements through siting and use of building form, materials, and envelope to enhance energy gain as well as energy retention and natural ventilation. Balancing Indoor Environment Qualities Designing for a high indoor environment quality can be challenging as all criteria need to be addressed while some may even contradict each other. Windows in particular need to be carefully designed - they influence access to daylight and ventilation, create heat gains in summer and losses in winter and provide a visual and acoustic connection to our immediate environment. Internal finishes not only impact internal sound quality but also influence a room’s thermal comfort, light reflectivity and air quality.