Strawclay bricks as insulation bricks for Passive solar heated buildings construction in Ladakh, India

Published on September 5, 2022

The straw which is a huge burden in the punjab region of India, is rescued and transported to Ladakh where it is used to manufacture straw-clay bricks, a local intervention. These straw-clay bricks are low-density and hence have higher insulation properties. Thus, a strawclay brick saves pollution twice, once in Punjab (or Delhi NCR) and then in Ladakh, a climate-sensitive zone. The project aims to mainstream the concept of passive solar heating and the use of high insulation in Buildings, It is critical that the local and national government make policy modifications and promote the usage of such low-carbon building materials that go beyond sustainability, and have a regenerative impact on the environment. It also aims to provide a low-cost, low carbon, solution to meet the space heating needs of the region through usage of sun above our head, earth below our feet and by-products of other processes. The project focuses on construction of passive solar heated buildings that donot need any active heating to maintain an indoor temperature of 15 degC using local materials and straw rescued from Punjab.

The project found that the PSH buildings stay at above 15 degC while the conventional buildings stay around 12-15 degC when heated and upto -5degC in the non-heated rooms. Furthermore, the entire cost of constructing a passive solar heated building can be recovered in around 11 years or lesser, depending upon the location of construction. The ouputs include:

1. The new design of PSH buildings at Phyang achieved indoor temperatures of around 22 °C average without any back-up heating when outside temperatures were around -10 to -15 °C when non heated rooms in non PSH buildings were at around -3 °C. 2. The PSH buildings are capable of achieving full autonomy through passive solar heating in Ladakh. 3. The cost of heating of conventional buildings exceeds the construction cost of the PSH buildings itself in roughly 11 years. 4. There is a need of developing a sustainable chain of transport of straw from Punjab to Leh. 5. There is a need to mechanise the straw-clay brick production to bring its cost down. 6. There is a need to incentivise PSH buildings in Ladakh. 7. Government will benefit immensely from incentivising these PSH buildings.

This case study is directly related to the work of the OPN SBC programme.