CARBSE

CENTRE FOR ADVANCED RESEARCH IN BUILDING SCIENCE & ENERGY

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Research & Development

Residential Characterization

Energy conservation building code 2006 (ECBC) meant to regulate commercial buildings in India. Next version of ECBC, called ECBC 2016 is to be based on multiple building types including multi family high rise residential building categorised by National Building Code (NBC).

CARBSE aims to build comprehensive understanding about residential sector, energy consumption and thermal comfort. The study focuses to gain understanding about residential typologies, construction practices, design parameters and campus level planning. Study attempts to bring out inferences focused towards climate responsiveness, thermal comfort, electricity consumption and integration of renewable energy. The study envisages to feed in to future residential energy conservation documents in terms of designing the guidelines to develop code and provide the framework to BIS and BEE.

Impact of ECBC on building energy consumption at city level, Phase 3

In 2016, CEPT worked on Impact of Energy Conservation Building Code (ECBC) at city level and quantified energy savings by examining available floor space within city for six cities i.e. Ahmedabad, Jaipur, Udaipur, Kakinada, Pune and Pimpri Chichwad. CEPT wish to create prototype model for city level energy conservation prediction by correlating existing building stock, their spatial distribution and land use.

Study aims to identify future stock of buildings in Ahmedabad and help city better manage their energy supply scenario in a city. Study aims to help utility company supplying electricity to city of Ahmedabad co-relate seasonal load variations and causes of peak demand, city level administration to understand impact of ECBC on commercial and residential sectors. Since this study relies more on spatial configurations, it envisages to help identify opportunities to reduce peak energy demand and also help evaluate potential of roof top SPV integration potential. Such study is going to be precursor to city level stock modelling which can be replicated in othercities specially aiming to work towards Smart City title.

Potential Energy Saving due to ECBC Implementation – A case study of Ahmedabad

Energy savings by Energy Conservation Building Code (ECBC) implementation with regards to estimation of floor space at city level had been a challenge. Precise understanding of current floor space stock along with its historical growth pattern can help estimate floor space at city level. The study attempts to evaluate present floor stock at city level with the help of tax data base. Tax data base is one of the accurate and trusted source for building floor space information at city level. Tax database is a widly used instrument to collect annual property tax within city, which is a reliable source to understand amount of floor space, its associated use, building characteristics and age relying on vintage value of floor space. All Urban Local bodies (ULB’s) across India have this mandate of collecting and maintaining property tax database. Understanding of present and future floor space is significant parameter to quantify ECBC impact.

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Developing A Tiered Approach for ECBC Compliance

Background: The Bureau of Energy Efficiency (BEE), India, launched the Energy Conservation Building Code (ECBC) in 2007. Through mandatory compliance with the ECBC, India can achieve estimated annual energy saving of 1.7 billion kWh. The rate of compliance with the code is predicted to reach 65% by 2017.

Overview: The objective of this project was to develop a tiered approach to facilitate compliance with the ECBC. In order to achieve this objective, individual ECBC measures were evaluated for energy savings, incremental cost, and ease of enforcement. The findings were peer reviewed and the measures were then bundled into tiers. Lower tiers include ECBC measures that are easier for the market to adopt, and are enforceable through the current building permit process. This will help to build capacity over time and allow developers to get experience on the subject matter of building energy efficiency, without reducing stringency of the code. This approach can be enforced more effectively given the current construction and real estate practices.

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The Third Party Assessor Model for ECBC Compliance and Enforcement

Background: The Bureau of Energy Efficiency (BEE), India, launched the Energy Conservation Building Code (ECBC) in 2007. In order to achieve significant compliance and subsequently, higher energy savings, the code must be adopted by the states and enforced by local governments. However, government and public sector agencies currently do not have the manpower or expertise to enforce ECBC. It is, therefore, crucial to build capacity and create a cadre of professionals outside the public sector.

Overview: The objective of this project was to develop a framework for Third Party Assessor (TPA) model to facilitate ECBC compliance and enforcement. In order to develop this framework, various successful TPA models in India and worldwide were studied. Some of these TPA models were related to building energy codes or ratings systems, while others were from the non-building sector, but offered valuable insights towards developing a TPA model for ECBC implementation and enforcement in India. A large stakeholder engagement provided useful feedback for the development of the TPA’s role and organizational framework.

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Low Energy Cooling Products, Technical potential and market Analysis

The India specific adaptive model called IMAC developed by CEPTUniversity opens avenues for application of non-conventional cooling technologies for use ofbuildings in India. These technologies have the potential to provide comfort while requiring relatively lower amounts of operational energy. The study assesses the potential of energy savings by using such low energy cooling systems while maintaining a thermally comfortable environment inside buildings in India. The study focuses on standalone systems primarily used in residential or small commercial building sectorsIMAC is to be taken as reference to evaluate performance of selected systems in achieving thermal comfort.

CARBSE team have received R&D grant from Department of Science and Technology to improvise low energy cooling systems. Based on scientific rigor and market analysis, CARBSE envisages a definite document establishing energy saving potential due to such systems if deployed at large scale in India and a framework for evaluating such systems on common platform. Study provides an opportunity to understand potential to offset energy consumption by conventional HVAC system by deployment of low energy cooling systems.

Deployment of adaptive thermal comfort model on space cooling technologies and energy saving potential

In the absence of space conditioning standard contextual to Indian context, the space conditioning systems for buildings are designed based on ISO and ASHRAE thermal comfort standards. Field observations have indicated that these systems often operate at 22.5 ± 1°C (72.5°F ± 1.8°F) all year round without adjusting to comfort needs of the occupants. Such operational practices are largely attributed to an increased expectation for stable comfort conditions.  In the absence of space conditioning standard contextual to Indian context, the space conditioning systems for buildings are designed based on ISO and ASHRAE thermal comfort standards. Field observations have indicated that these systems often operate at 22.5 ± 1°C (72.5°F ± 1.8°F) all year round without adjusting to comfort needs of the occupants. Such operational practices are largely attributed to an increased expectation for stable comfort conditions. 

India’s Energy Conservation Building Code (ECBC) references National Building Code for ventilation guidelines in naturally ventilated buildings, but it does not deal with conditioning requirements contextual to climate zones. In the ECBC user guide, the Bureau of Energy Efficiency (BEE, 2009) also recommends “Adaptive comfort model” as “additional information” to users.



However, the ECBC remains silent on the recommended temperature and humidity conditions for space conditioning of buildings for Indian climatic conditions.  CEPT, with support from SSEF and MNRE (Govt of India), has developed adaptive thermal comfort model contextual to climate conditions in India. This study addressed comfort expectations of office workers in naturally ventilated building, mixed mode buildings (buildings which rely on mechanical cooling systems to maintain thermal comfort only during adverse outdoor conditions) and air conditioned buildings Study found strong evidence that Indians can be comfortable at higher temperature than 24 degree centigrade fix temperature across the year. Study also indicates wider range of temperature adaptability of Indian subjects.

Deployment of adaptive thermal comfort standard is expected to save enormous amount of savings, however, no significant study has been carried out to understand larger benefit of such standard. Adaptive thermal comfort standard also will allow many other non-conventional, Low energy cooling technology to serve space cooling requirements. Identification of such technology will also make path of wider range of product availability in Market. Following graph illustrates that hot and dry climate, ECBC envelop can provide decrease in uncomfortable hours, remaining uncomfortable hours can be served with low energy cooling systems.

Impact of Energy Building Code at City level:

City administration consumes large amount of their financial resources on electricity to manage city level facilities such as street lights, water pumping, and their own buildings – hospitals, ward offices, and essential services. During CEPT’s study on Benchmarking of city administration buildings, it became apparent that the city administration does not have required processes and systems to take informed decision as well as to implement energy efficiency measures.

Local city governments are smallest and yet the most important units in implementation & enforcement of ECBC. To understand energy saving potential of implementation of ECBC at city level, city needs to collate data regarding new building construction and their probable usage. To link present land use, floor space character, future land use allocation, and future energy demand are essential to parameter to understand impact of energy efficiency in buildings. This also will be able to provide insight in to change in peak demand, which will be of interest to utility.

Presently, no such mechanism does exist to access information regarding available floor space and future addition in it. ULB do not have framework in place to collate this information. Few city level administrations have created energy conservation cells but they are not mandated to work in conjunction with Town development or estate offices, and hence do not focus on ECBC. It is important for city administrations to develop such processes to envisage benefits of ECBC implementations.

CARBSE proposes to study one city in detail to develop processes that can be practiced to achieve energy efficiency at buildings owned by city government and understand enforcement of ECBC at city level.

Potential for Maintaining Comfort and Achieving Energy Savings in India using Low Energy Cooling Technologies

In the absence of space conditioning standard contextual to Indian context, the space conditioning systems for buildings are designed based on ISO and ASHRAE thermal comfort standards. Field observations have indicated that these systems often operate at 22.5 ± 1°C (72.5°F ± 1.8°F) all year round without adjusting to comfort needs of the occupants. Such operational practices are largely attributed to an increased expectation for stable comfort conditions.

CEPT has developed adaptive thermal comfort model contextual to climate conditions in India. This study addressed comfort expectations of office workers in naturally ventilated building, mixed mode buildings (buildings which rely on mechanical cooling systems to maintain thermal comfort only during adverse outdoor conditions) and air conditioned buildings. Study found strong evidence that Indians can be comfortable at higher temperature the year with wider range of temperature adaptability of Indian subjects.

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Calibrated Building Energy Simulation

Background: Building simulations and energy calculations based on detailed modeling form an extremely important tool for design and investigation of energy efficient buildings. Various building components and building forms can be tested for their performance to help for the design right at the start as well as analyse the performance of an existing building. These simulation methods also help formulate policy level decisions. However, when the results of such simulated building models are compared to on site measurements; there is bound to be differences. Simulation tools are developed across the world based on empirical data, research, computational skills and software development, yet it is believed and understood that discrepancies against actual measured data is inevitable. This huge gap in the knowledge database needs to be addressed and studied, especially for the Indian context. The idea is to study these differences and derive parallels relations between simulated data and on-site measured data.

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Building Management System for Net-zero Energy Building (NZEB)

Net-Zero Energy Building (NZEB) is envisioned as a living laboratory for continuous and in-depth building energy-efficiency research. To achieve the goal, building design contains sophisticated and flexible control systems that can support continuous research experiments on building monitoring and performance optimization. The control system in the building is designed to meet the following 

objectives:
- To serve as a single platform for monitoring and controls in the building
- To provide testbed for development of new technologies and control algorithms
- To integrate with test chambers for effective operations and controls

Figure 1: Details of Monitoring, Integration and Controls Philosophy

Building control system continuously monitors installed components and uses efficient algorithms to optimize building performance. The building design incorporates sophisticated controls strategy such as demand ventilation, economizer based on enthalpy, chilled water reset, heat recovery wheel optimization algorithm, and chiller performance optimization.

The control system will also be able to configure various indoor comfort condition algorithms such as operation based on schedule, based on custom adaptive comfort equation, and based on equation of outdoor/indoor conditions, or based on PMV algorithm. Key energy and operational parameters would be continuously displayed on display screen located on the ground floor.

Testing facility to measure daylight performance of Tubular Daylighting Devices (TDDs)

Providing daylight in the spaces is crucial for energy conservation as well as health and wellbeing and improved work efficiency of human beings. Tubular Daylighting Devices (TDD – also called Light pipes) are simple means of directing daylight (diffuse and direct light) from the sky into interior spaces and provide natural light in those areas of the building with limited or no access to daylight. TDDs consist of three parts: outside collector, tube to transport daylight and a diffuser inside the room. CARBSE is developing a test facility to enable the testing of TDDs for VT (visible transmittance) and Solar Gain based on International Standards. The visible transmittance (VT) is an optical rating that determines how much light in the visible spectrum is transmitted through a window glazing or other fenestration. The VT measurement of a TDD must accommodate the geometrical complexity of light entering and exiting the device at angles that are more variable than those associated with flat window products. Therefore, an integrating sphere with two meter diameter, also known as Large Diameter Integrating Sphere (LDIS), is used. TDD is mounted on the LDIS and the lux meters placed inside the LDIS measure average distributed non-uniform light that enters the sphere from TDD sample. A single VT result will represent the total transmission integrated over all various output angles for a given solar incidence angle that can be adjusted by the positioning of the LDIS relative to the sun.

Mirror Box – Artificial Sky – constructed at CARBSE for daylight analysis

Center for Advanced Research in Building Science and Technology (CARBSE) has constructed a Mirror Box to create Artificial Sky conditions. A mirror box is used to simulate overcast sky conditions for building models, which can help architects and engineers to understand daylight inside the building and take necessary design decisions to increase building performance and reduce energy consumption for artificial lighting. A mirror box consists of an extremely bright homogenously lit ceiling and mirrored walls. The light source is a milky white diffusing acrylic sheet illuminated with over 6,000 LEDs behind. The mirrors, arranged vertically all around the periphery of the boxproduces an image of the lit ceiling by reflection and inter-reflection to infinity. The building model to be analysed for daylight performance is placed inside the mirror box and illuminance levels are measured using lux meters to determine daylight factor.

Single Patch Sky Simulator getting constructed for daylight analysis

Center for Advanced Research in Building Science and Technology (CARBSE) is constructing Single Patch Sky Simulator which can be used to simulate Artificial Sky. It can create various sky conditions for building models to be analysed, which helps architects and engineers to understand daylighting inside the building and make necessary changes to the design and specifications of glazing to increase building performance and reduce energy consumption for artificial lighting. The system consists of a turntable, mirror and customized LED luminaire. Building model to be analysed for daylighting is fixed on turntable’s platform. Turntable can rotate the model about two axis. This turntable receives light from LED luminaire lamp after getting reflected from the mirror. The lamp emulates one sky patch out of the total 145 virtual divisions of the sky dome as per Tregenza’s model. Turntable rotates the model such that the lamp is positioned in each of the 145 divisions of the sky dome. For each division, illuminance levels are measured inside the space using lux meters. These measured readings are then combined and computed using algorithms to give daylight performance of the space. Schematic design and analysis are completed and execution is under process.

Reducing global energy use in buildings while improving occupant comfort & well-being

Buildings contribute to greenhouse gas emissions more than the industrial or transportation sectors, primarily due to high energy demand and usage in air conditioning, heating and ventilation, driven by the basic human need for thermal comfort and good indoor air quality. The projects aims:
- to achieve a better understanding of human thermal comfort in residential and commercial buildings
- to explore opportunities for reducing energy demand through natural ventilation, mixed mode practices and other low energy techniques that provide air movement.

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Development of an India Model for Adaptive (thermal) Comfort

Background: Given India’s rapid economic growth and concomitant expansion in its commercial sector, soaring demand for air-conditioned commercial buildings can be confidently predicted. This increased demand for air-conditioned buildings in India has been attributed to an increased expectation for stable comfort conditions as the workforce shifts away from an industrial production towards a service-orientation that is office-based. If permitted to grow unchecked, building air-conditioning will add immense pressure on electricity infrastructure and exacerbate the already extreme peak-demand problem in the country.In the absence of an adaptive thermal comfort standard specifically focused on India’s climatic and cultural context, the recent trend in India is to design air-conditioned office buildings (that often operate at 22.5 ± 1 °C all year round) to meet the “Class A” comfort specifications articulated in documents such as ISO 2005 and ASHRAE 55 for air-conditioned buildings. This approach may elevate Indian comfort expectations to levels that require unsustainable energy inputs, without substantially improving overall occupant comfort, satisfaction and productivity.

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Building Material Characterization And Construction Assemblies

Background: India is experiencing tremendous expansion in Building Construction Industry. Influx of new material has increased in last decade. Building Energy Efficiency and Integration of Renewable Energy Sources has become imperative to meet the global challenges. Building Materials play major role in achieving energy efficiency with the built environment. Number of computer models have been developed and are practiced across the country, which help professionals in envisaging future energy demand within and outside buildings.However, thermo-physical-optical property of locally available building materials is very limited and at the same time, the characterization of newly developed building material is also not very much in public domain. To enhance performance of building material and construction assembly, it is very essential that such knowledge gets created and gets disseminated to all stakeholders.

About Project
Exercise will develop extensive data of thermo-physical-optical property of building materials, building components and construction assemblies. State of the art material testing facilities will be used to characterize materials. Opaque building materials such as clay bricks, gypsum, stones, cement and RCC will be characterized for its thermal conductivity, thermal diffusivity, specific heat, density etc. Transparent – translucent materials such as glass, acrylics will be characterized for transmittance, absorptance and reflectance. Subsequent to data base for material, database for construction assemblies such as walls, roofs and components such as windows, skylights and doors will be developed. Online web tool will be developed to facilitate the use of acquired knowledge. This study is an effort initiated by Centre of Excellence in Solar Passive Architecture and Green Building Technology, Centre for Advanced Research in Building Science and Energy (CARBSE) at CEPT University and is supported by Ministry of New and Renewable Energy, Govt. of India. CARBSE is also partnering with local Indian academic and research institutes to accomplish this exercise.

Click to view Brochure - Building Material Characterization And Construction Assemblies

Supported by:

Ministry of New and Renewable Energy Govt. of India, Gujarat Energy Development Agency, U.S. Agency for International Development iNDEXTb (Industrial Extension Bureau) Govt. of Gujarat, Shakti Sustainable Energy Foundation, New Delhi