What is the ideal building orientation according to this code?

The long axis should be oriented East-West to minimize heat gain on the larger wall surfaces and maximize controllable southern exposure (Clause 4.3).

What are the main passive heating concepts mentioned?

Direct Gain (sunlight through windows), Indirect Gain (using a thermal mass like a Trombe wall), and Isolated Gain (collecting heat in a separate space like a sunroom) (Clause 6).

What is a Trombe wall?

It's an indirect gain passive heating system comprising a dark-colored masonry wall with an air gap and exterior glazing to trap and slowly release solar heat (Clause 6.3).

How can passive cooling be achieved in buildings?

Through strategies like shading of windows and walls, promoting natural ventilation (cross-ventilation and stack effect), and using evaporative cooling (Clause 7).

IS 12818

: 1990

Guidelines for design of solar passive buildings

CurrentSpecializedGuidelinesBIMArchitectural · Green Building and Sustainability

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This standard provides guidelines for designing energy-efficient buildings by utilizing passive solar techniques. It covers key principles such as building orientation, form, envelope design, shading, and natural ventilation for thermal comfort. The code aims to reduce reliance on active heating and cooling systems by optimizing the building's interaction with the local climate.

Provides principles and guidelines for designing buildings that harness natural solar energy for heating, cooling, and lighting, reducing conventional energy demand.

Quick Reference Values

Recommended Building OrientationLong axis oriented East-West

Recommended Window Opening for Cross-Ventilation15% to 20% of floor area

Thermal Mass Wall Thickness for Hot-Dry Climate200 mm to 300 mm

Roof Insulation U-Value for Hot-Dry Climate< 0.4 W/m²K

Recommended Reflectivity for External Walls (Hot Climate)> 0.70

Practical Notes

This code is a foundational guideline; for detailed energy performance calculations and compliance, refer to the Energy Conservation Building Code (ECBC).

The principles are highly climate-zone dependent. Strategies must be adapted for hot-dry, warm-humid, or composite climates as defined in SP 41 or the NBC.

Effective passive design requires an integrated approach, considering architectural form, material selection, and site planning from the initial concept stage.