Passive Design Heating & Cooling
Content: An integrated approach to Daylighting Passive Heating and Cooling
The useful practice of the ‘ancients’ should be employed on the site so that loggias should be filled with winter sun, but shaded in the summer.
-Leone Battista Alberti, De Re Aedificatoria, 1452
Good passive design, like sustainable design in general challenges the boundaries between design disciplines and takes into account ecology, economy and equity. Other aspects of good passive design include understanding the differences between Passive and Active Design strategies. Good passive design finds clues in the Vernacular Design of the region and incorporates sound Passive Design Fundamentals.
Passive solar design is holistic and is fully integrated into the building's architecture. It consists of glazing orientation, sizing and materials selection as well as mechanical systems type and sizing (for reduced heating and cooling loads) It takes into consideration local climate conditions, such as temperature, solar radiation, wind and terrain. The key objectives of passive design are to create climate-responsive, energy conserving structures that can be powered with compact and robust renewable energy sources.
There are three basic Types of Passive Systems: Direct Gain, Indirect Gain and Isolated Gain. The three fundamental components of a passive heating system are:
1. There are three basic Types of Passive Systems: Direct Gain, Indirect Gain and Isolated Gain.
2. The three fundamental components of a passive heating system are: South facing glass
3. Thermal mass to absorb, store, and distribute heat
Thermal Mass is crucial to any passive design whether for heating or cooling purposes. Thermal mass provides a two-fold benefit:
1. It provides a delay in thermal transfer – or lag time.
2. It has a dampening effect on thermal transfer.
The result is the an effective stabilization of internal versus external temperature swings. Steps in Designing a good passive building:
1. Site and orient the building appropriately for the latitude, climate and regional weather conditions taking full advantage of available solar energy.
2. Optimize the building envelope – insulation in the walls and roof.
3. Optimize use of daylight and passive solar gain, i.e. include the appropriate window area and orientation.
4. Provide Solar Control through the use of overhangs, shades, grilles, living walls, etc.
5. Integrate the appropriate types and amounts of thermal mass inside the building envelope to store and redistribute heating energy and to minimize temperature swings.
6. After performing computer energy simulations design appropriately sized mechanical Heating cooling and ventilation systems.
7. Integrate natural (daylight) and electrical lighting and design lighting and environmental controls to reduce energy demand.