On an average, India has more than 3000 Cooling Degree Days (CDD). The multifamily public housing being constructed under India’s Prime Minister Awas Yojana (PMAY) is aimed at providing formal housing to the society’s Economic Weaker Section (EWS). It is essential that this housing delivers thermally comfortable indoors to the
Abstract: Final energy use for cooling in buildings has tripled between 1990 and 2016 to 2020 terawatt hours. Excluding China and Japan, India accounts for about 28% of RAC penetration is comparatively lower at 5% in India but raising with 12% CAGR growth. Use of RAC provides thermal comfort leading to better living standard, simultaneously use of energy and refrigerant to operate RAC impact environment. Seasonal Energy Efficiency Ratio (SEER) is the most used method to quantify the energy efficiency of RAC. The importance of comprehensive environment impact, accounting direct and indirect emissions by RAC will help mitigate environmental challenges. This paper adopts a methodology using ISO 16358-1 combined with hourly temperature bin to calculate Indian SEER (ISEER). Cooling Seasonal Energy Consumption (CSEC) is developed as a metric accounting different climate represented by cities and comfort models. Total Equivalent Warming Impact (TEWI) was used to account direct (refrigerants) and indirect (energy consumption) emissions. The study accounts for 12 Indian cities having high GDP growth, four RAC selected out of 282 RAC surveyed for the study. In comparison of ISEER mentioned by BEE, the study observes 9-20% higher ISEER in New Delhi and 9-16% lower in Bangalore. CSEC and TEWI are observed to be highest in Ahmedabad and lowest in Bangalore with a maximum difference of 2,520 kWh/year and 20,640 CO2-eq respectively. For Delhi, CSEC was observed at 23% lower with adaptive comfort model for AC operation building then static comfort model. The contribution of direct emissions to TEWI was observed 10-20% with R410a and 4-8% with R32.
Abstract: In India, the energy end-use is anticipated to increase by 56% from 2014 to 2050. It shares 12% of total carbon emissions in the world by Room As increase in energy production using fossil fuels has an adverse effect on climate, there is an immediate need to focus on mitigation scenario. It counts on the change of refrigerant, improvements in system design efficiency and operational approach. Growth in urbanization and rising income is persuading the use of mechanical cooling for better comfort. Seasonal Energy Efficiency Ratio (SEER) is the most used method to quantify efficiency of RAC. Environmental impact of the system is still unexplored. This paper summarizes a methodology proposed to determine the effect of energy performance and indoor comfort temperature in total environmental impact by a RAC. The study was conducted in four stages. Initially, relevant metrics were identified from past work to quantify the parameters. 12 Indian cities were selected based on GDP growth for analysis. Four RAC units were selected based on findings from market survey of 282 RAC systems available in the country. In the third stage, ISEER and annual energy consumption were calculated for 12 cities using ISO 16358-1 and temperature bin hour calculations. Carbon emissions were calculated using Total Equivalent Warming Impact (TEWI) score which comprises of direct (refrigerants) and indirect (energy consumption) emissions. Further, annual discomfort degree hours were calculated to quantify the cooling demand for static and adaptive indoor set-point temperatures. Lastly, the results obtained show that the dependence of carbon emissions is more on annual cooling hours (comfort) than the system seasonal energy performance. Above 40°C, for peak load conditions only 5 cities experience more than 20 hours annually. Savings of more than 60% in total environmental impact can be achieved by incorporating adaptive indoor set-point temperatures.
Abstract: Different methods are used for calculating the energy consumption of buildings. While the heat balance method, weighing factor method and thermal network methods are complex and require In this study, we have used the degree-day approach published in CIBSE TM-41 to develop a Python tool to calculate the energy consumption of energy buildings on an hourly basis. The tool calculates the building energy for 59 Indian cities for five different cases: 1) fully air-conditioned, 2) with evaporative pre cooling, 3) evaporative cooling, 4) with comfort cooling and 5) with night ventilation with five different thermal comfort models. These cases are run for two building versions: 1) Business as Usual and 2) Energy Conservation Building Code compliant , and the study resulted in two realistic versions of Balance Point Temperatures for these cases. In total these add up to 2900 simulation which the Python tool completes within 1 hour. The results are shown in an excel dashboard.
The results indicate the cooling energy reduction possible due to the three passive design strategies. The CDD-based results are compared with EnergyPlus results. The Normalised Mean Biased Error is 4.6% while the Root Mean Squared Error value is 15%.
Abstract: As energy consumption from residential buildings is predicted to rise by more than eight times by 2050, it is of vital importance for India to develop energy-efficiency This study investigates impeded growth in energy consumption in the Indian residential sector and documents energy saving potentials that can be achieved with the focused policy and market efforts. The study specifically focuses on assessing the role of building envelopes in relation to comfort air conditioning systems and appliances in order to ensure energy efficient dwellings for urban and rural residential sectors.
The study conducted a survey of 800 households, in four-climate zones of India, to map current equipment penetration rate and electricity consumption patterns. Key information including residential unit area, monthly energy consumption, connected load, number of appliances & their power rating, as well as operational patterns, has been gathered in a survey. Building energy modeling (using EnergyPlus) was then deployed to quantify comfort benefits and energy savings potentials of better performing building envelopes.
The trends observed during survey and building energy modeling analysis, along with the information from past studies, have been used to derive residential electric energy projections till 2050. The projections in the study have been segregated by three end use segments (air conditioning, envelope, and equipment) for urban and rural residential sectors. Projection scenarios show that the electricity consumption will rise by more than eight times under the business-as-usual scenario. With the focused policy and market efforts, the electricity rise in residential sectors can be restricted to five times, four times, and three times that of current energy use under modest, aggressive, and very aggressive scenarios.
Abstract: Various works carried out by Centre for Advanced Research in Building Science and Energy (CARBSE) at CEPT University, Ahmedabad, has been discussed in this paper. The objective The proposed Third Party Assessor framework can resolve the issues of capacity and expertise to enforce ECBC at the local government level. However, coordinating with different government agencies and other relevant stakeholders to incorporate the TPA framework would be a challenging and time-consuming initiative. A tiered approach to ECBC compliance has been proposed wherein, Tier 1 includes those requirements of ECBC that are easy for market adoption, have a high energy savings potential, and are enforceable through the current building permit process, while tiers 2 and 3 include additional measures of ECBC that are more difficult to implement or enforce, given the current practices, and have a lower potential for energy conservation.
Abstract: Compliance with Energy Conservation Building Code (ECBC) of India can save up to 1.7 billion kWh annually. ECBC enforcement poses significant challenges to local governments who are This paper summarizes two important initiatives taken up in India for making implementation and enforcement easier, leap-frogging the challenges that have been experienced in other countries.
In the first initiative, the United States Agency for International Development supported the development of the ECOnirman Whole Building Performance Tool, an online code compliance energy simulation tool. It assists developers and building designers in demonstrating performance-based compliance. It shows great promise for the future in India: it enables building developers to meet code by installing only those measures that improve their building's energy performance; it promotes innovation in design and technologies; it enables a large user-base to do energy simulations and results in true capacity building; and the database of inputs and results enables policy analysis. Tying the metered energy use of the buildings to the ECOnirman database will result in a robust dataset that will be a powerful policy tool for future programs, rating and labelling of buildings.
The other code compliance initiative is a nationwide Third Party Assessor (TPA) framework for compliance checking of ECBC. Urban Local Bodies (ULB) that enforce building and development rules and bye-laws, face technical and manpower related challenges when enforcing ECBC. This paper discusses the background research, the stakeholder engagement, and the institutional framework proposed for allowing a TPA model to be used across India.
This paper provides recommendations and next steps for ECBC compliance through future development of ECOnirman and implementation of the TPA framework.
Abstract: India has experienced an average economic growth of 10% since 1991 leading to the establishment of new commercial buildings. Amongst other initiatives, Indian government enacted the Energy Government of India is relying on mandatory building energy code and voluntary standards and labeling (S&L) program to foster energy efficiency in commercial buildings. Learning from S&L home appliances program the government has initiated the formation of building component labelling programs for windows, walls and roof. This paper is part of a research that aims to map the state of current affairs in Indian fenestration industry and fenestration labelling programs from across the world. The research involves evaluation of thermal and optical performance of windows available in Indian market and compares them against those prescribed in the energy code. Further it suggests mechanisms for the formation, implementation and administration of window labelling program in India. This paper also focuses on estimation of energy saving potential of high performance window systems, their payback period by using a combination of window simulation program such as WINDOW-THERM-Optics and whole building energy simulation program such as EnergyPlus.
Abstract: In the next 18 years, India will add 67% of the floor space projected for 2030, or about 2.3 billion square meters. Buildings consume 33% of total For a large scale market change, the Bureau of Energy Efficiency developed the Energy Conservation Building Code (ECBC). Through mandatory ECBC compliance, India can achieve an annual energy saving of 1.7 billion kWh. The rate of compliance with ECBC is forecasted at 10% until 2013, 35% in 2015 and 65% by 2017. To achieve this, ECBC must be adopted by the states and barriers to enforcement by local governments must be overcome.
Shakti Sustainable Energy Foundation funded a study to develop a tiered approach to compliance, with evaluation of individual ECBC measures for energy savings, incremental cost, and ease of enforcement. The findings were peer reviewed and the measures were then bundled in to tiers. Lower tiers include ECBC measures that are easy for market adoption, and are enforceable through the current building permit process. This will help build capacity over time and allow developers to get experience with building energy efficiency. It will help enforce ECBC and build capacity at same time without reducing stringency of the code. This approach can be enforced more effectively given the current construction and real estate practices.
This paper summarizes the analysis and presents the policy case for the Tiered approach.
Abstract: Urbanization has direct impact on the spatial structure of the city, which in turn results in the dramatic change of the overall immediate environment. High-rise, high density It is often seen that this heat gets re-radiated & trapped due to neighborhood buildings causing changes in surface & ambient air temperature. To mitigate such effect various approaches were studied and experimented in the past. Out of which impact of vegetation is considered to be one of the most potent measure to mitigate negative impact of urban form on high surface and air temperature. This is proved through number of research studies and on-site measurements. This study is an approach to understand the role of urban environment on urban area micro-climate with reference to vegetation in the city of Gandhinagar, India. An urban area of Central Business District is configured according to the rules of ground coverage, floor space index (FSI) and site setback as mentioned and laid out in building byelaws of city. For the purpose of this study a three dimensional numerical computer model ENVI-met V3.4, that analyzes micro scale thermal interaction with urban environment is used. Input of environmental data is extracted from Ahmedabad IWEC weather file. Simulations are done for typical summer day. Parametric variations are made to get prediction of surface and air temperature in different built and un-built conditions. Different scenarios are designed besides the model condition where studies are done on basis of different surface materials, changing density of vegetation & changing the type of vegetation. The results are evaluated on the basis of ambient air temperature & Surface temperature. Findings show that on an average 2°C drop in ambient air temperature is achieved in urban area of Gandhinagar’s microclimate with the addition of trees. Vegetation is seen more valuable during harsh afternoon hours, due to its shading and evapo-transpiration properties. This suggests that shading streets with trees is advisable, which results in achieving reduction of minimum 0.5°C & maximum 1.5°C average air temperature across the year. The cooling effect of trees is also seen in the surrounding areas. Strategic plantation of trees and selection of surface material is found as very important aspects to lower adverse effect of urbanization.
Abstract: The Energy Conservation Building Code (ECBC) was launched in India in May 2007 under the Energy Conservation Act, 2001. It offers two compliance approaches - Prescriptive and According to the EC Act, compliance with the ECBC has to be expressed in terms of Energy Performance Index (EPI) which is the annual energy consumption per square meter of floor area, and is only possible via the WPB compliance approach. However, as the Prescriptive compliance approach is relatively easy to implement and enforce, it may be assumed that once ECBC is made mandatory at local level, the Prescriptive approach will be a more widely used compliance path over WBP owing to ease of integration with the existing building regulations. This paper aims to link ECBC Prescriptive requirements to the EPI performance metric in order to bridge the gap that exists between EC Act and ECBC Prescriptive compliance method.
The simulation results help in understanding the relative impact of ECBC Prescriptive requirements and prioritizing the Energy Conservation Measures (ECMs). The results are extrapolated to understand the long-term impact of the code on national energy savings. The paper also provides an insight into the sensitivity of the various ECMs in different climatic zones.
Abstract: The study focuses on ways to minimize interior lighting energy consumption (ILEC) in daytime use office buildings and proposes use of solar photovoltaic’s (SPVs) to suffice the The objective of the study is to attain interior lighting energy autonomy through Solar Photovoltaic’s. The study in whole focuses on low interior lighting energy consuming building designs whose interior lighting electricity loads are almost entirely met by grid connected roof top SPV systems. Energy Conservation Building Code (ECBC-2007-India) compliant hypothetical building models representative of office buildings in the hot-dry climate of Ahmedabad were modeled in Design Builder on Energy Plus platform. Fifty-four scenarios in all were examined for three-floor plate areas (500, 750 & 1000 m2). The scenarios were derived by keeping the carpet area constant of all the floor plates and varying building aspect ratios, orientation (1:1, 1:2 & 2:1), window wall ratio (40% & 60%) and applying external daylighting devices such as louvers and light shelves. From these scenarios, one building case for all the three different floor plates with the least ILEC was proceeded to integrate rooftop-grid SPV system (24KW SPV system for 500 m2, 36KW SPV system for 750 m2 and 48KW SPV system for 1000 m2 ) to arrive at potential energy generation figures. The study analyzed the two aspects – Energy and Economics, of the attempt. For first Energy analysis, the study analyzed annually to hourly interaction between the building’s ILEC and SPV energy generation. On annual basis, the study was able to illustrate a potential scenario to serve ILEC of 3.8 floors for 500 m2 floor plate, 3.4 floors for 750 m2 floor plate and 3.2 floors for 1000 m2 floor plate of the same building by the same roof top SPV system designed as per floor plate areas. These results were also due to interaction of energy imports and export with the utility grid but the system annually made no net demands on the utility grid to serve ILEC. This meant that ILEC of more than three floors of a building for all three-floor plate areas were demonstrated to be net zero by integration of SPV roof top system.
The results of three floor plates also demonstrated that with every increase of 250 m2 floor plate area, there is a percentage increase of 56.8% in annual ILEC, with percentage increase of 50% in annual roof top energy generation, with percentage increase of 62.5% in annual energy imports from the grid, with percentage increase of 46.5% in annual energy exports to the grid. This implies that with increasing the floor plate area as the core area increases, there is a percentage decrease of 32.8% in annual net surplus energy on site.The second analysis Economics part, the study projected the life period energy summary to obtain life period cost summary of the installed SPV systems, which demonstrated that rooftop SPV system is still very high capital incentive investment with payback period of 22-24 years, without considering any government subsidiaries. Overall, the study demonstrates a sustainable approach towards interior lighting energy use in the building sector by utilizing renewable solar energy source.