Solar passive design techniques
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Solar passive design techniques
- 1. Passive building DesignAldo Leopold Centre, Barabou, Wisconsin – Carbon Neutral + LEEDTM Platinum
- 2. Presentation Summary In this presentation, we will discuss the basic principles of: • Passive Heating – Solar geometry • Passive Cooling – Wind and shading • Day-lighting – Indirect lighting and materials issues
- 3. Aims & Objective AIM: • To study different types of solar architectural and constructional techniques for designing different buildings. OBJECTIVE: • To promote energy efficient building design , to minimize energy use and negative environment effect of building • To maximize use of renewable and natural resources in building environment • Building Construction with optimum use of solar energy • Thermal comfort for the inhabitants • To reduce maintenance cost.
- 4. What is Passive Design? • is based upon climate considerations • attempts to control comfort (heating and cooling) without consuming fuels • uses the orientation of the building to control heat gain and heat loss • uses the shape of the building (plan, section) to control air flow • uses materials to control heat • maximizes use of free solar energy for heating and lighting • maximizes use of free ventilation for cooling • uses shade (natural or architectural) to control heat gain
- 5. Passive Buildings Require Active Users • Unlike most contemporarily designed buildings that rely on “Thermostat” control to regulate the temperature and relative humidity (comfort) in buildings, Passive Buildings require occupant involvement to ensure their success. • Occupants need to be EDUCATED as to when to open and close windows, raise and lower shades, and otherwise control some of the non automated means of controlling the effects of the sun and wind on the interior environments of the building.
- 6. Differentiating Passive vs. Active Design Passive design results when a building is created and simply works “on its own”. The plan, section, materials selections and siting create a positive energy flow through the building and “save energy”. Active design uses equipment to modify the state of the building, create energy and comfort; ie. Fans, pumps, etc. Passive buildings require active users (to open and shut windows and blinds…)
- 7. Passive Means of Design
- 8. The Tiered Approach to Design Image: Norbert Lechner, “Heating, Cooling, Lighting”
- 10. Understanding solar geometry is essential in order to: - do passive building design (for heating and cooling) - orient buildings properly - understand seasonal changes in the building and its surroundings - design shading devices - use the sun to animate our architecture Why Solar Geometry? Image source: university of waterloo
- 11. In studying Solar Geometry we can figure out how to use the sun’s natural path in summer vs. winter to provide FREE heat in the Winter, and to reduce required COOLING in the summer. Image: Terasen Gas, Surrey, BC Canmore Civic Centre, Canmore, AB
- 12. Solar geometry works for us because the sun is naturally HIGH in the summer, making it easy to block the sun with shading devices. And it is naturally LOW in Winter, allowing the sun to penetrate below our shading devices and enter the building - with FREE SOLAR HEAT.
- 13. Passive solar heating Passive solar HEATING in a building aims to maintain interior Thermal Comfort. Image: Druk white lotus school, ladakh
- 14. Reduce Energy Loads: Passive Strategies The tiered approach to reducing energy requirements for HEATING: Maximize the amount of energy required for mechanical heating that comes from renewable sources. Tier 1 Tier 2 Tier 3 Maximize Heat Retention Passive Solar Heating Mechanical Heating
- 15. MAIN STRATEGIES: •Direct Gain • Thermal Storage Wall •Sunspace The dominant architectural choice is Direct Gain. Passive Solar Heating Strategies
- 16. 1. Conservation Levels: Higher than normal levels of insulation and airtightness 2. Distribution of Solar Glazing: distributed throughout the building proportional to the heat loss of each zone 3. Orientation: Optimum within 5 degrees of true south 4. Glazing Tilt: Looking for perpendicular to sun angle in winter, although vertical efficient where lots of reflective snow cover 5. Number of glazing layers: 3 to 4 for severe climates, less otherwise 6. Night insulation: Greatly improves reduction of night heat losses 7. Mixing passive systems can increase comfort levels. General Rules for Passive Solar Heating
- 17. This space is using classic Direct Gain for heat. The sun shines through the windows. Strikes the exposed concrete floor. Heat is absorbed into the concrete as it is an excellent thermal mass. When the space cools off, the heat is radiated into the space making it warm.
- 18. These are cross sections of the space pictured on the previous slide. The sun heats the corridor space during the day and the openings between the space allow for heat transfer into the occupied space behind. At night the openings are closed off to help the space to retain the heat.
- 19. Passive Cooling Passive cooling systems are least expensive means of cooling, which maximizes the efficiency of the building envelope without any use of mechanical devices.
- 20. The tiered approach to reducing energy requirements for COOLING: Maximize the amount of energy required for mechanical cooling that comes from renewable sources Tier 1 Tier 2 Tier 3 Heat Avoidance Passive Cooling Mechanical Cooling Reduce Energy Loads: Passive Strategies
- 21. As much as possible, passive cooling uses natural forces, energies, and heat sinks. Since the goal is to create thermal comfort during the summer (the over-heated period), we can either : • cool the building by removing heat from the building by finding a heat sink • raise the comfort zone sufficiently to include the high indoor temperature by increasing the air velocity so that the comfort zone shifts to higher temperatures. What is Passive Cooling?
- 22. Passive cooling relies on two primary strategies: • First and foremost, prevent heat from getting into the building! If it does not come in, we don’t need to get rid of it. - use shading devices - create a cool microclimate to discourage heat buildup • Get rid of unwanted heat that comes into the building - in cold and temperate climate, mainly via ventilative cooling Passive Cooling Strategies
- 23. • Exhausting warm building air and replacing it with cooler outside air • Directing moving air across occupants’ skin to create convection and evaporation • Achieved by the wind, stack effect or fans. What is Ventilative Cooling?
- 24. Vegetation can be used to shade the building and create a cool micro climate around the building.
- 25. Courtyard spaces can provide a cool semi private interior microclimate from which to draw cool air into the building.
- 26. Day-lighting does not equal to sunlight! Day-lighting is about bringing natural LIGHT into a space. Many day-lit spaces do not WANT or NEED direct sunlight. Direct beam of sunlight may HEAT the space. Image: Beijing National Theatre
- 27. Reduce Energy Loads: Daylighting The tiered approach to reducing energy requirements with DAYLIGHTING: Use energy efficient fixtures! Maximize the amount of energy/electricity required for artificial lighting that comes from renewable sources. Source: Lechner. Heating, Cooling, Lighting. Tier 1 Tier 2 Tier 3 Orientation and planning of building to allow light to reach maximum no. of spaces Glare, color, reflectivity and material concerns Efficient artificial Lighting w/ sensors
- 28. Day-lighting is environmentally advantageous because : • reduces the need for electric lighting • therefore reducing the energy needed to power the lights • reducing the heat generated from the lights • thereby reducing the cooling required for the space DIRECT SUNLIGHT is about FREE HEAT. DAYLIGHT (diffuse light) is about free LIGHT. Differentiating Passive Solar Heating and Daylighting
- 29. Daylighting concepts prefer diffuse or indirect lighting. With the proper use of shading devices to block direct sun penetration into the space, all exposures of the building can receive diffuse light rather than direct sunlight. It is necessary to differentiate strategies as a function of building use.
- 30. Light is an important architectural DESIGN TOOL. It has the ability to bring architecture to life. It relates to the use and cultural identity of the building. Image: City Centre, Las Vegas
- 31. Light can be use to reveal EXPERIENCE Image: Seattle Public Library | Rem Koolhaas
- 32. Light can be use to reveal FORM Image: EMP, Seattle | Frank Gehry Architect
- 33. Light can be use to reveal SPACE Image: British Museum, Norman Foster
- 34. Light can be used to reveal MEANING Image: The Pantheon, Rome
- 35. Advantage of Passive building Design • Eliminate heating and cooling costs • Reduce greenhouse gas emissions • Clean process • Eco-friendly • Cost-effective • Attractive living environment • Low maintenance Disadvantage of Passive building Design: • Great deal of work for the engineers to arrange this system. • Careful construction required • Improperly designed not work well • Sunshine not available all day • Extra heat and the higher temperatures
Notas del editor
- This presentation, What is Sustainable Design? Part Three: The Basic Principles of Passive Design, is intended to provide an overview of the methods to be used to design buildings to minimize their need for fossil fuels and maximize their sustainable qualities.
- In this presentation, we will discuss the basic principles of: Passive Heating Solar geometry Passive Cooling Wind and shading Daylighting Indirect lighting and materials issues
- What is Passive Design? Passive design is: is based upon climate considerations attempts to control comfort (heating and cooling) without consuming fuels uses the orientation of the building to control heat gain and heat loss uses the shape of the building (plan, section) to control air flow uses materials to control heat maximizes use of free solar energy for heating and lighting maximizes use of free ventilation for cooling uses shade (natural or architectural) to control heat gain It attempts to use natural principles in order to substantially reduce dependence on fuel based technologies for heating, cooling and lighting the building.
- Passive Buildings Require Active Users Unlike most contemporarily designed buildings that rely on “Thermostat” control to regulate the temperature and relative humidity (comfort) in buildings, Passive Buildings require occupant involvement to ensure their success. Occupants need to be EDUCATED as to when to open and close windows, raise and lower shades, and otherwise control some of the non automated means of controlling the effects of the sun and wind on the interior environments of the building. Sometimes Passive Buildings, due to limitations in achieving an interior climate that falls in the middle of the “comfort zone”, will require occupants to accept a wider range of acceptable temperature and relative humidity values.
- Differentiating Passive vs. Active Design Passive design results when a building is created and simply works “on its own”. The plan, section, materials selections and siting create a positive energy flow through the building and “save energy”. Active design uses equipment to modify the state of the building, create energy and comfort; ie. Fans, pumps, etc. Passive buildings require active users (to open and shut windows and blinds…)
- Passive Means of Design The chart above outlines the basic passive strategies that can be used for climate control to reduce energy requirements. If we consider winter to be the heating season, we have to both promote solar gain and resist heat loss from our buildings. If we consider summer to be the cooling season, we have to both resist solar gain and promote heat loss – precisely the opposite of the winter condition. The sun, the wind, the earth and the atmosphere are used very naturally to achieve this.
- Energy Reduction works with the tiered approach to design. Tier one asks that we get the basic building design to be climate responsive through basic design of the building itself. Tier two adds passive systems for heating and cooling. These will not work if the basic design is wrong. Tier three adds mechanical systems. If these cannot be very very small, they will not be able to be powered by the renewable energy available on or around the site. Traditional, contemporary building design STARTS with assuming that EVERYTHING will be powered with mechanically based systems.
- Solar Geometry The study of solar geometry is essential to understanding how to both obtain free heat (passive heating) and reduce the amount of cooling through heat avoidance (passive cooling) on a building project. Solar angles vary in accordance with your position on the earth as well as the time of year.
- Why Solar Geometry? Understanding solar geometry is essential in order to: - do passive building design (for heating and cooling) - orient buildings properly - understand seasonal changes in the building and its surroundings - design shading devices - use the sun to animate our architecture The Perimeter Institute in Waterloo uses the sun to daylight and add character to the space.
- In studying Solar Geometry we are going to figure out how to use the sun’s natural path in summer vs. winter to provide FREE heat in the Winter, and to reduce required COOLING in the summer. We need to understand how to manipulate the geometry over the time of day and seasons of the year so that we can properly design shading devices to keep unwanted sun and heat out of our buildings in the summer time, and allow the same into our buildings in the winter time.
- Solar geometry works for us because the sun is naturally HIGH in the summer, making it easy to block the sun with shading devices. And it is naturally LOW in Winter, allowing the sun to penetrate below our shading devices and enter the building - with FREE heat.
- Reduce Energy Loads: Passive Strategies The tiered approach to reducing energy requirements for HEATING begins with Tier 1, Maximize Heat Retention. In a northern climate this will include increases in the normal levels of insulation, providing thermal mass to store the heat, and making the building air tight to prevent losses through cracks. After we build an efficient building we can then use solar heating to heat the building. The heat will have thermal mass to be stored in and will have insulation and a leak free envelope to prevent losses. Mechanical heating can then be reduced to top off the amount that is not able to be supplied passively.
- Passive Solar Heating Strategies There are 3 MAIN STRATEGIES used in building design to admit and store the free heat from the sun. These are: a. Direct Gain b. Thermal Storage Wall c. Sunspace The dominant architectural choice is Direct Gain as it clearly uses the windows to admit the sun and the materials inside the building to store the heat. In a Thermal Storage wall thermal mass is placed between the windows and the interior space to absorb the heat and allow for a slow transfer to the interior spaces. This precludes the use of the windows as vision glazing. In a sunspace (and this is not the same as a classic sun room or solarium) the space between the glass and thermal storage wall is enlarged to permit seasonal use of the space.
- General Rules for Passive Solar Heating 1. Conservation Levels: Higher than normal levels of insulation and airtightness 2. Distribution of Solar Glazing: distributed throughout the building proportional to the heat loss of each zone 3. Orientation: Optimum within 5 degrees of true south 4. Glazing Tilt: Looking for perpendicular to sun angle in winter, although vertical efficient where lots of reflective snow cover 5. Number of glazing layers: 3 to 4 for severe climates, less otherwise 6. Night insulation and Low-E glazing: Greatly improves reduction of night heat losses 7. Mixing passive systems can increase comfort levels.
- This space is using classic Direct Gain for heat. The sun shines through the windows. Strikes the exposed concrete floor. Heat is absorbed into the concrete as it is an excellent thermal mass. When the space cools off, the heat is radiated into the space making it warm. It is important to have enough thermal mass of adequate thickness to absorb the available heat from the sun. If the thermal mass is insufficient, then the heat will be absorbed by the occupants, who at 80% water, are an excellent source of thermal mass! It is also important to avoid floor coverings such as wood and carpet as these are insulating materials and will prevent the heat from being absorbed into, and reradiated from, the concrete. Staining the concrete can provide an attractive architectural finish.
- These are cross sections of the space pictured on the previous slide. The sun heats the corridor space during the day and the openings between the space allow for heat transfer into the occupied office space behind. At night the openings are closed off to help the office space to retain the heat.
- Reduce Loads: Passive Strategies The tiered approach to reducing energy requirements for COOLING starts at Tier 1 with Heat Avoidance. What you do not admit into the building you do not have to get rid of. Tier Two applies passive cooling. This will include using natural ventilation to get rid of unwanted heat and humidity as well as impact the choice of materials. Some materials can make the building and its occupants feel cooler. Tier Three uses Mechanical Cooling to make up the difference. Less mechanical cooling will be required if the loads are reduced through passive means.
- What is Passive Cooling? As much as possible, passive cooling uses natural forces, energies, and heat sinks. Since the goal is to create thermal comfort during the summer (the over-heated period), we can either : cool the building by removing heat from the building by finding a heat sink raise the comfort zone sufficiently to include the high indoor temperature by increasing the air velocity so that the comfort zone shifts to higher temperatures.
- Primary Passive Cooling Strategies Passive cooling relies on two primary strategies: 1. First and foremost, prevent heat from getting into the building! If it does not come in, we don’t need to get rid of it. So - use shading devices - create a cool microclimate to discourage heat buildup. (This can be done by planting trees, shrubs and vines around the building. Avoid dark coloured pavement and finishes). 2. Get rid of unwanted heat that comes into the building - in cold and temperate climate, mainly via ventilative cooling
- What is Ventilative Cooling? 1. Exhausting warm building air and replacing it with cooler outside air 2. Directing moving air across occupants’ skin to create convection and evaporation 3. Achieved by the wind, stack effect or fans. You have to not only provide openings but also, locate them correctly, make sure they are large enough, for this to work properly!!
- Vegetation can be used to shade the building and create a cool micro climate around the building.
- Courtyard spaces can provide a cool semi private interior microclimate from which to draw cool air into the building.
- Daylighting does not equal sunlight! Daylighting is about bringing natural LIGHT into a space. Many daylit spaces do not WANT or NEED direct sunlight. Direct beam sunlight is about HEATING the space.
- Reduce Energy Loads: Daylighting If we can light our interiors via daylight during the daytime hours, and also ensure that the lights are OFF when not in use, we can save a great deal of energy. The tiered approach to reducing energy requirements with DAYLIGHTING begins by making sure that the orientation and exposure of the building and openings in the façade will allow light to reach the maximum number of occupied spaces. Secondly we have to consider the colour, reflectivity and materiality of the materials in and around our buildings. Light coloured materials will work to bounce light and create for a light interior. Dark materials will absorb light and require more light to reach proper levels for the occupants to use the space. Lastly, we use energy efficient artificial lighting with occupancy and light level sensors to make sure that the lights are off when not required.
- Differentiating Passive Solar Heating and Daylighting DIRECT SUNLIGHT is about FREE HEAT. DAYLIGHT (diffuse light) is about free LIGHT. Daylighting is environmentally advantageous because it: reduces the need for electric lighting therefore reducing the energy needed to power the lights reducing the heat generated from the lights thereby reducing the cooling required for the space
- Daylighting concepts prefer diffuse or indirect lighting. With the proper use of shading devices to block direct sun penetration into the space, all exposures of the building can receive diffuse light rather than direct sunlight. It is necessary to differentiate strategies as a function of building use.
- Light is an important architectural DESIGN TOOL. It has the ability to bring architecture to life. It relates to the use and cultural identity of the building.
- Light can be use to reveal EXPERIENCE Seattle Public Library by Rem Koolhaas uses the contrast of light and shadow that is cast by the diagrid to create an exciting experience as you head towards the entrance.
- Light can be use to reveal FORM Experience Music Project, Seattle by Frank Gehry Architect uses light to create a play of shadow on the curved forms and help to define the sculptural forms.
- Light can be use to reveal SPACE British Museum Central Courtyard by Norman Foster uses the extreme brightness provided by the skylight and the light coloured stone materials to real the character of the space.
- Light can be used to reveal MEANING The Pantheon in Rome relies on the light from the 20 foot oculus to wash the interior with a gentle, inspirational level of light.