Environmental and comfort upgrading through lean technologies in informal settlements: Case study in Nairobi, Kenia and New Delhi, India

Informal settlements, namely slums (or bidonville or favelas) are one of the stronger challenge for urban context in developing countries. The increase of urban population leads to a widespread poverty and critical life conditions for a large segment of population, in particular in Sub-Saharan Africa, where a high percentage of people lives in informal settlements. The problems in slums are multiple: people suffer malnutrition and poor sanitation, flooding or drought, and live in shelters providing no thermal comfort in many days of the year, furthermore scarce and highly polluting energy sources are available. Climate change and an unavoidable heat island effect make these living conditions nearly catastrophic. This paper focuses on the main characters of these slums and on how to what promote the improvement of living conditions with a lean, low cost, low impact, feasible upgrading of the housing or more properly shelters. The subject of the analysis is the Mathare 4A Upgrading Programme in the city of Nairobi, Kenya, one of the highest slum-dwellers growing rate. The technological solutions applied in this context have been verified in a different climate condition such as the city of New Delhi, India where the phenomenon of the slums is significantly burdensome. The analysis of the comfort conditions inside a type housing has been carried out using hourly weather data and dynamic heat transfer simulation, without any HVAC system and striving only natural ventilation. Data about internal temperature and relative humidity conditions have been applied to evaluate the comfort hours using the Predicted Mean Vote method, the adaptive thermal comfort principles and the bioclimatic charts for the two climates in Nairobi and New Delhi. The percentage of hours within the comfort range and the amount of degree-hours exceeding comfort values showed for different upgrading strategies, how it is possible to deeply influence the living conditions by technological and affordable choices on the envelope of such simple housing. A simplified LCA (Life Cycle Assessment) evaluation on embodied energy in the proposed upgrading materials used for the housing allows assessing the environmental impact of the considered alternatives. The present study aims to find out and to propose lean technological solutions to improve users’ comfort levels with simple DIY (do it yourself) modification of shelter’s envelopes and basic education for the use of the housing. The paper presents the study of lean technological solutions to improve comfort conditions and durability of informal settlements located in two climate zones in the world where slums are a critical issue in the urban development. The opportunity to improve such conditions can promote an upgrading of health and wealth status in such a critical situation in which millions of people are living today. The lean, affordable and low impact technologies that have been proposed and tested by dynamic simulation could allow a widespread diffusion of the concept without burden on the strongly compromised environment. The weak and fragile areas affected by the slums have pollution problems and a main task is not to worsen them during the life of the shelters/houses.