The objective of the Initiative for Global Urban Shelter (IGUS) has been to catalyze research to develop sustainable and resilient residential dwellings that can be scaled up in low-resource urban settings. Over the course of the past 4 years,two projects have been conducted, looking at cost-effective methods of improving thermal comfort and reducing the risk of building collapse from earthquakes.
Investigating Natural Ventilation Strategies to Improve Thermal Comfort for Multi-unit Residential Buildings in India
This project addresses the growing need for affordable cooling and ventilation systems in densely-populated multi-unit residential buildings (MURBs) in Mumbai, India. With long periods of extreme heat and high humidity, ventilation, cooling and dehumidification are the most important functions for building space conditioning systems in places like India. However, the challenge of a reliable supply of electricity, combined with the need for a low-cost solution, makes many conventional approaches to providing cooling in high-rise buildings impractical.
The focus of the research conducted within this project was primarily the development of passive or low-energy cooling technology designed for deployment at the suite-level. In the past year, research has focused on examining the effect of wind catchers and solar chimneys to help improve indoor thermal comfort. Using air flow simulations conducted used measured wind speeds in Mumbai and thermal comfort calculations, the implementation of wind catchers and solar chimneys in MURBs was selected as the most applicable passive cooling solution. Fundamental heat loss equations and duct loss design procedures were used to determine the sizing and feasibility of the solution and were verified against discretized calculation methods and computational fluid dynamics (CFD). The discretized results were found to be comparable to the CFD with an error margin of 10%. The combination of the wind catcher and solar chimney solution was able to reduce the total annual discomfort time by a minimum of 71% using ASHRAE Standard 55.
Developing a Frugal Seismic Isolation Platform for Low-Resource Urban Settings
It is estimated that over one billion people live in dwellings that are prone to collapse due to earthquakes, tropical storms, and other natural disasters. The consequences of such natural disasters are much more critical in resource-constrained urban settings with high population densities like in India. Although there exist modern building codes and construction regulations that are intended to prevent buildings from collapsing and save lives, imposing, implementing, and enforcing such regulations are challenging in developing countries.
The primary objective of this project is to develop new cost-effective seismic isolation platform (SIP) concepts that can be mass implemented for the most commonly designed buildings in urban settings in India. Currently, seismic isolation is costly and is mainly implemented in either high-end buildings or critical structures like schools and hospitals. The major advantage of the SIPs that were developed, which consist of a very low-cost and highly resilient layer that is built at the base of the buildings, is that they absorb the seismic energy that is induced by earthquake events at a fraction of the cost. This provides protection from earthquakes even if the buildings are designed and built with limited seismic resistance following current construction practices in India. Thus, the performance of these buildings to seismic action is greatly improved, not only ensuring that the buildings do not collapse and kill their occupants, but also reducing structural damage to a point where the structure can resume its function quickly after a major seismic event. In addition, the proposed system is also engineered to provide protection against floods.