A Study in Solar Housing Technology: The Impact of Trombe Walls in Ladakh

Abstract: The aim of this bachelor’s thesis is to examine the effect of installing a Trombe Wall in houses in Ladakh, India, and to evaluate its impacts for energy-saving, improvement in life quality, and its financial viability. Trombe Walls are a passive solar technology that use a dark wall with a glass covering to slowly heat living spaces by storing solar energy. Passive solar technology involves using the sun’s rays to heat or cool living areas without the aid of mechanical devices. In this thesis, two types of passive solar technologies are studied, Trombe Walls and direct gain technology. Direct gain technology is introduced in order to conduct a comparative study of Trombe Walls. Direct gain technology focuses on maximizing windows area to let in sunlight to warm the room. This was done through two-pronged approach. In a first quantitative step, data was collected from rooms heated by Trombe Walls and direct gain technology. In each room, data was recorded using temperature, humidity, pressure, and light sensors. This information was then used to analyze the indoor temperature of the rooms and calculate the solar radiation that hit the walls. This showed that Trombe Walls maintain a more stable indoor temperature as compared to direct gain technology, although often at the expense of the brightness of the room. Furthermore, a numerical model was developed to simulate the indoor temperature of a Trombe Wall. This quantitative analysis was complemented by a qualitative analysis where inhabitants from two villages in Ladakh were interviewed. All interviewees lived in houses heated by a Trombe Wall. The interviews show that Trombe Walls brings forth a myriad of positive effects, such as increasing indoor air temperature, improving air quality and generally raising the level of wellbeing in a family. Furthermore, a discussion of the economic feasibility of installing a Trombe Wall follows, to see if it is financially viable for villagers to adopt this technology. The Trombe Wall is analyzed as an investment using economic valuation tools such as the Internal Rate of Return method. Given current fiscal conditions in Ladakh, and that the lifespan of a Trombe Wall is at least 20 years, the Trombe Wall becomes a profitable investment for the individual if their required rate of return is less than 17 %. Lastly, this thesis concludes with a short discussion of how the quality of the data collected could be improved, as well as suggestions for future improvements to a Trombe Wall. Possible solutions are presented that might help make the Trombe Wall a more appealing heating solution and enable the technology to spread around the world.