Tiêu đề Building Envelope Cooling inspired by Evapotranspiration in Trees_for UIA Conference 23.pdf ✅

Keywords: Second Skin, Envelope Cooling, Building Facade, Biophilic Facade, Terracotta, Porous Ceramics, Low Carbon Cooling Solutions, Nature Inspired Cool- ing System, Evapotranspiration, Biomimicry, Passive Cooling Building, Aerofoils, Climate Responsive Facades Abstract Buildings suffer from uncontrolled heat gain through their skin which cre- ates the urgent need for thermal comfort, resulting in the extensive use of Air con- ditioning systems. Emissions through ACs inevitably lead to ‘heat islands’ in cities creating a ‘butterfly effect’ in warming up the macro-climate, leading to what we can call the ‘Cooling Paradox’. Trees have been the ideal natural cooling sources within our ecosystem by performing evapotranspiration. Inspired by this natural process, a design that utilizes the potent combination of terracotta and water that is receptive to moss strives for ecologically regenerative goals. This combination cools and purifies the air, targeting multistoried buildings. An inclusive future calls for the concept of Envelope cooling, addressing the question of rethinking our cool- ing techniques and creating an optimized terracotta second skin for buildings that combines passive shading with active evaporative cooling and ventilation strategies to create a low-tech, equitable design. A hybrid jali inspired by the geometry of Aerofoils which is optimized to channelize airflow, creating a nozzle effect and a flexible installation that can tailor to different locations and sun angles. Envelope cooling could reduce the energy load of cooling the buildings by up to 30%, result- ing in energy savings by cutting the heat gain right at its source. The overall design of the system and its materials reduces the optimum electricity load of the buildings, attributed to the low carbon footprint. Its climatically adaptive design holds the po- tential to influence the shape of future buildings, landscapes, and cities with earthy tones. Introduction In hot climates such as India, a growing economy with a rising per capita in- come is leading to an increased demand for cooling. Most of this demand is at- tributed to the construction industry as space cooling in buildings. According to the India Cooling Action Plan (ICAP) by the Ministry of Environment, Forest and Climate Change, the cooling demand in the building sector is expected to rise by 11 times in the next two decades.
2 Space Cooling: Increasing demand for RACs and the ‘Cooling Paradox’ At present, the penetration of air-conditioning in India is lower than the world- average (Ministry of Environment, Forest, and Climate Change, 2019). However, owing to the combined effect of rising per-capita income, rapid urbanization and tropical climate, demand for cooling is bound to rise. Currently, a large part of the cooling demand is matched by using active refrig- eration and air conditioning (RACs), which mostly rely on the use of synthetic re- frigerants. While new and less harmful refrigerants are being tested, most of the industry only has access to harmful refrigerants causing a rise in global warming. The International Energy Agency (IEA) reports that 10% of global CO2 emis- sions are the contribution of RAC technologies. As a result, significant heat is trapped due to gasses released from the air conditioning refrigerants consequently adversely affecting the city’s microclimate. According to some studies, a city with a population of one million is, on average, 3° C hotter than its surroundings (Mi- trica, 2014). Using RACs for cooling our indoors effectively heating up our outdoors. This leads to an increased demand for indoor cooling, what we can call as the ‘cooling paradox.’ Need for Passive Cooling Strategies in India Building envelopes, comprising roofs and facades, are constantly exposed to in- tense heat and solar radiation. In tropical regions, where temperatures are already rising above thermal comfort levels, such thermal transmission has an adverse ef- fect on indoor spaces. (Latha, Darshana, Venugopal, 2015) RACs not only have a degrading effect on the environment, but they are also en- ergy intensive. In Indian homes, for example, 20-40% of the electricity usage is at- tributed to ACs (Khosla and Chunekar, 2017). Therefore, striving to reduce the demand for cooling energy in buildings while providing thermal comfort becomes important. Use of passive cooling strategies, by reducing the direct heat gain into the build- ings, is the first step in reducing the energy demand for cooling. This is also rec- ognized by ICAP: the adoption of climate-appropriate building envelopes has the potential for reducing cooling energy demand by 20% by 2037-38 (Ministry of Environment, Forest and Climate Change, 2019). Moreover, a thermally comforta- ble building design is also a step towards climate resilience, resonating with
3 UNSDGs of Sustainable Cities and Communities1 , Responsible Consumption2 and Production and Climate Action3 . Exploring nature-inspired cooling solutions for Building Envelopes Traditional Passive Cooling Facades Traditionally in India, buildings were designed in consideration to the environ- mental context which channelized air and sun into the building interiors in a way that reduced heat gain and increased the thermal comfort (Verma, 2021). Fig 1. Jharokhas of Jaisalmer Fig 2 Jaalis in composite climate zone 1 UNSDG 11: To make cities and human settlements inclusive, safe, and resili- ent. 2 UNSDG 12: To Ensure sustainable consumption and production patterns 3 UNSDG 13: Take Urgent action to combat climate change and its impacts