Directed Research Projects

space cooling and lighting in commercial buildings account for nearly two-thirds of the overall consumption. Providing cooling has become unavoidable and designing mechanical systems to provide comfort efficiently is a challenging task. Low energy cooling systems are designed to consume less energy while providing adequate comfort levels. These systems are often coupled with passive cooling approaches and less widely studied in isolation.

to determine energy performance of building. Correct input parameters help predict accurate building energy performance. Amongst other parameters, following three parameters are influenced by local context and hence needs to be derived through various sources locally. They are

used commonly, both in residential and commercial buildings, which results in large energy consumption. As per India Energy Report 2015 by IEA, the air conditioner consumes almost five times as much electricity as an evaporative cooler- which consumes twice as much as electricity as a fan. But an extensive study, suggests elevated air movements can provide indoor cooling effect using less energy in warm environment. The purpose of this study is to evaluate a range of air velocity, which can be deemed desirable, while being used along with Air Conditioning. A series of experiments shall be conducted in a controlled environment (28˚C-32˚C; 60% and 80% RH) to test different air velocities provided by a selective air motion devices. Also, their energy consumption shall be recorded.

the changing climate, increasing temperatures and purchasing power in metropolitan cities like Mumbai, Bangalore, Delhi and Chennai has led to an exceptional growth in the use of mechanical systems. The economic affordability and availability of these air- conditioning systems has increased the use of mechanical cooling in buildings and has made it a default practice. Today, India’s building energy use accounts for 33% of the nation’s energy use, and this is growing by 8% annually. But scientific studies determine various comfort and adverse health effects associated with the characteristics of buildings, ventilation and conditioning systems and these poorly designed indoor environments and people today spend about 80-90% of their time indoors. Thus this paper aims to understand, explore and learn the well-being and comfort of Occupant's in their space of work and provide optional innovative approaches to maintain and enhance their health and productivity. This paper would investigate and examine the selected office buildings on the basis of three key aspects;

studies have shown advantages of such systems, this study takes a leap forward by examining effectiveness of movable external shading system by deploying scientific rigour. The study evaluates impact of external movable shading in hot and dry climate of India using three approaches – using energy and daylight simulations, using laboratory apparatus, and using field data under controlled conditions. The study starts with one week long field work for daylight study, then validates daylight results with laboratory apparatus and finally calculates overall savings using simulation models. The movable shading system was studied for its effectiveness in four direction North South East W along with 20% - 40% -60% Window to wall ratio and opening condition, fully closed, fully open and partially open at 30 degree, 45 degree and 60 degree to evaluate thermal and daylight results obtained under environmentally controlled indoor conditions. Based on field study, various shading system configurations have been prepared for daylight study. The study uses artificial sky generation consisting of Single Patch Sky Simulator (SPSS) and Mirror Box to study daylight performance of the models under clear and diffused sky conditions. The overall energy savings for the buildings have been then calculated using energy and daylight simulations using DesignBuilder, EnergyPlus, and Radiance software. The simulation assesses impact of external movable shading devices for various window orientations, window-to-wall ratios, and shade openings in the building. Study reveals that external movable shading devices have potential to reduce 15-30% of energy consumption while providing comfortable lighting level inside building.

performance, health and well-being. Large floor plates for offices accommodates open plan layout, which help to meet contemporary functions of offices. In such cases dependence on electric light increase, leading to higher lighting energy consumption. Limited technologies are available to increase penetration of daylight into the large floor plates. Laser Cut Panels (LCP) is one of the promising technologies, helping reduce electric lighting consumption by illuminating larger floor plates with daylight. This study investigates performance of LCP in three locations in India. Study starts with to develop Bi-directional scattering distribution function (BSDF) to be used within simulation program that assesses the solar and optical performance of LCP. Study relies on combination simulation program such as EnergyPlus for daylight analysis, Ecotect for LCP geometry, Radiance genBSDF for generating BSDF data and visualizations. A business as usual case of a typical office floor plate was considered as reference model. Three variations in LCP geometry and design, three variations in window to wall ratio, combination of LCP on four orientation of window was investigated. Results generated from simulation run are then analyzed in terms of electric light energy savings and spatial distribution of daylight for different variables.

lighting can be achieved by installing energy efficient lighting system or by increasing presence of daylight. Penetration of daylight can also bring solar radiation and associated heat component inside the building which increase the cooling demand in air-conditioned buildings. Optimum window area, glazing properties and nature of shading devices will help negotiate between availability of daylight and heat ingress due to solar radiation. This study investigates the impact of climate conditions, glazing systems, Window-to-Wall Ratio (WWR), and orientation on energy demand of building. This study is based in context of climates of Ahmedabad, Bengaluru and Chennai. This study was conducted using COMFEN – a tool based on EnergyPlus simulation engine. A case was developed based on business as usual office floor space. Study analyzes spatial pattern of daylight and energy consumption simultaneously.

world since 1960s about the deterioration of the environment. “The material from which products are constructed makes a significant contribution to its overall impact on the environment. Its influence is felt in number of ways; locally, through the effects of activities such as quarrying; globally, as a result of carbon dioxide emission by using energy used to manufacturing the materials; and the internally, in the effects on the health of the occupants of the building.”(Harris,D.J) Building efficiency has been the guiding factor in today’s designing so realizing improvement in building performance is to accurately quantify the environmental performance of building materials. Materials used might be light in weight and efficient but on the other scale have high embodied energy, chemicals and not defined lifecycle. These after their life are disposed to landfills and only 15-20% goes to reuse where its outcome is down-cycled rather than up-cycle. Thus it becomes important to understand how different material can be disassembled and distributed in different cycle (Biological and Technical) to have an efficient materials cycle for better use and reuse. So the study aims to understand impact of different materials used in the interiors of building on environment. So to work towards understanding materials and component involved in product and thus distributing materials into biological and technical cycle, thus making efficient material and energy flow. To create data base for material banking and material passport system to support material pooling and reuse for up-cycling. Thus exploring the benefits of alternative materials, processes and material recapture through reuse, remanufacturing or recycling, or a whole new way to meet a need in Indian context based on Cradle to Cradle principles which can be used as a design aid, and its use is illustrated with a case study of a typical Office in India.

wall assemblies has an important impact on the indoor air quality and thus human health. This study focuses on understanding the moisture migration properties of different wall assemblies and their impact on the indoor air quality. This indoor air quality further affects the health of building occupants, so it would be an attempt to assess the impact of moisture migration properties on occupant’s health. In the process, the functional and hygrothermal properties of different building materials would be depicted from data collected and experimental studies. This data would, further, be used to perform thermal and hygrothermal simulations in naturally ventilated buildings. Simulated thermal and humidity profiles would be assessed. Lastly, the study would confirm the effect of moisture migration properties of wall assemblies on the IAQ of naturally ventilated buildings and their impact on occupant’s health.

with the increase in the gross domestic product (GDP). One area with significant energy and emissions reduction potential is residential end-uses, as urbanization and rising incomes continue to drive household ownership, usage and demand for residential energy services. The growing trends of urbanization, rise in per capita income are pushing up the requirement for housing units and its impact on the overall electricity consumption. In this paper, i will evaluate the potential of maximizing India’s residential equipment efficiency and the subsequent electricity demand implications through 2025. A detailed LBNL bottom-up, end-use energy model will be used to highlight residential end-use energy linkages between urbanization, economic development and India’s growing building sector. The study would be an attempt to understand the reasons and impact on overall energy consumption and peak energy demand, at the same time an attempt, in forecasting future ownership trends for the largest household energy consuming appliance, an econometric model correlating historical ownership rate to income would be made. The study relies on walk through audits to map the energy consumption along with the parameters such as building character, occupancy and the presence of electrical appliances. Household and personal factors will be assessed by a socio economic self administered questionnaire. The study would include data collection of about 300 samples, representing middle and high middle income group. All the samples would be from Pune, which falls under warm and humid climate zone. Study will attempt to include diverse residential buildings. Gathered data would be analysed with an aim to understand how the usage of electricity in residential house result from a complex interaction between built form, location, energy using equipments, air conditioner tonnage, light loads, number of occupants and other economic factors.

visual connection to the outside environment. They, on the other hand, also become a medium for heat transfer between outside and inside affecting the thermal comfort. The study analyses different window configurations used over the last hundred years to understand this belief. It also aims at understanding various approaches and strategies used and derived over the time for shading openings on the facades that include shutters and external shading devices. This research would map evolution of fenestration design and run simulations models to evaluate the visual and thermal performances of the same. The study would conclude with an understanding of relation between changes in window design to their energy performance.

largely ignored plug loads which might be attributed to a dearth of India-specific studies which quantify plug-load energy consumption and their usage characteristics through end-use measurements. Field studies in 30 typical offices covering a total floor space of 8000 m2 and 1160 plug loads were carried out to find plug load consumption characteristics. The study shows plug loads as significant consumers of electricity and reveals wide gaps in design and actual on-site provision for these loads that need to be addressed. The study also quantifies the contribution of standby power from major plug loads found in offices.

as well as thermal comfort of occupants in office spaces and analyses it in all the climatic regions of India. The investigation of the mutual relationship between thermal comfort and energy demand is of the foremost importance to define the benchmarks for energy service to calibrate the energy usage. The result of variations in setpoint temperature per degree rise (for a range of 22°C- 28°C) and COP (for a range of 2.0 – 5.0) on cooling load in office spaces are studied. The primary intention of this work is to provide a detailed look at the overall effect on energy consumption of these setpoint temperature changes while considering the range of inhabitant’s thermal comfort and their response to the each one degree rise of setpoint. As many studies have shown that discomfort due to improper indoor temperatures affects productivity adversely. Since India is blessed with varied range of temperatures, it would be interesting to note the alterations on energy consumption and thermal comfort range in different climatic regions. The influence on energy demand of the expected level of thermal comfort and of system control strategies has been investigated by means of simulations.

subject to study. Substantial amount of energy is spent in the transportation and manufacturing process of various building materials. Walling materials used in the envelope of the building are those related to high embodied energy consumption due to their transportation energy, production energy and for improving building’s operational energy. The objective of this study is to identify walling materials which may optimize a building’s energy requirement over its entire lifecycle, by estimating and calculating both embodied and operational energy consumption in buildings particularly in Ahmedabad region (Hot and dry climate). A comparison of embodied energy of alternative walling materials has been made with reference to building’s operational energy requirement. It has been observed that embodied energy of 1 cu m masonry can be reduced by 70% when alternative walling materials are used.

under monolithic walls are brick and stone, cavity walls with varying cavity thicknesses and insulated walls with XPS and EPS on outside and inside. There are two cases of monolithic walls, two cases of hollow block, three cases of cavity walls and four cases of insulated walls. In all eleven cases of composite wall assemblies, simulation is carried out. All the cases are simulated for conditioned and naturally ventilated environment for design day and design week of May and December. The effect of location of insulation, the amount of thermal mass required to attain 2°C of temperature variation from outside to inside, transient heat transfer happening with in the assembly, influence of the layer distribution and thickness on the thermal behavior, are the concerns for which the analysis is being done. The investigation is carried out for the climatic conditions of Ahmedabad, during representative days for May & December. The initial temperature distribution across the wall is assumed to be uniform and equal to the daily mean external air temperature. Orientation and inclination of the assemblies is also kept constant for all the cases. The entire exercise is simulation based in WUFI Software. The effect of insulation location on the heat transfer characteristics of building wall elements under initial transient conditions is studied. Thermal performance with an insulation layer placed on the inside of a wall is compared to that when the insulation layer is placed on the outside. The results of model application under the present conditions show that placing the insulation on the outside proves more helpful. The heat flux values are noted over the first 24 hours and compared for various wall assemblies, seasons and insulation locations.

buildings cannot be naturally illuminated by side windows, and therefore, such areas depend entirely on electricity for illumination. The work done n the present study is an attempt to find out the benefits of using daylight device technologies to enhance natural illumination of deep plan office buildings. The focus of this study is to determine appropriate passive daylight device for office buildings in the city of New Delhi, India, and helps to understand the barriers that prevent harnessing in the daylight to its maximum potential. This study takes into account the prevailing building typologies in the commercial sector. Four hypothetical models have been derived subsequently by analyzing the existing office buildings typologies of the city. After developing the hypothetical models, various windows to wall ratios have been applied to understand the availability of daylight in these models. The study addresses to three daylighting devices which are available in the international market – light shelves, Anidolic light ducts, Light tubes. The integration of selected devices with the hypothetical models has been considered for more than one scenario, which studies and examines its appropriateness for daylight usage. This entire exercise has been carried out using validated simulation program. The formulation of the simulation exercise has been established on the available weather data. Experiments have been carried out under sunny sky conditions and CIE overcast sky. The exercise also evaluates the cost effectiveness of the integration of daylight device within existing buildings to increase daylight availability and thereby reduced energy loads because of artificial lighting systems. Hence it tries to assess the cost effectiveness of application of such devices. The study demonstrates the technical & economic viability of passive daylight devices in the context of New Delhi, India.

most energy efficient and at the same time most economically viable insulating material when used on the external wall of the building is developed in this paper taking Ahmedabad as an example. Thus the paper explores the potential of these insulation materials to reduce the cooling load in office buildings when used on inside of a wall. The optimization is based in life cycle cost analysis. A hypothetical model through survey of office buildings typical of practice in Ahmedabad is evolved for the study. An excel worksheet is prepared through which the heat gain/loss through the differently oriented walls of the building façade is calculated using finite difference method. The payback period and life cycle cost for each of the insulating material selected is then comparatively analyzed on the cost of insulating material and annual cooling loads. The results show that most energy efficient material in terms of energy consumption is polyurethane foam of 75mm thickness and gives savings of 23% annually as compared to base case. However 50mm polyurethane gives a payback year of 1.5 years. In term of life cycle cost over 50 years, 75mm polyurethane proved to be better material than others.

efficient building. In recent years, daylighting of deep plans has become very important, not only to reduce total energy consumption of the building but also to provide healthy spaces for the users. Daylighting helps to design a visually comfortable space depending upon the function of the space. Innovative daylight redirection systems can be used to enhance indoor daylighting using available sunlight. This study evaluates the daylight redirection systems like light shelves and anidolic ducts, these systems are reviewed and a comparison is made with respect to efficiency, light output and light redirection. It is only a simulation based study and not an experimental one because of the stipulated time frame. This study specifically shows the case of office building in Mumbai. In this study a high rise office building “Commerze- II” Oberoi garden city, Goregaon(E) is modeled in Rhino and simulated in Diva for Rhino by integrating the daylight redirection systems in the four orientations while taking a hypothetical surroundings into consideration. The hypothetical surroundings is derived based on the survey conducted for 25 buildings to find two most common sky exposure angles found for High rise office buildings in Mumbai. Simulation is done according to the IES LM 83 document guidelines for sDA and ASE. The study suggests the pros and cons of these systems over each other for the modeled High-rise building in Mumbai to optimize the daylight performance of the building based on the analysis of simulation results.

new areas are been dedicated for the industrial set ups outside the city. The industries which are getting build in these areas do not have enough space between the two sheds to have adequate amount of light from the windows. Some industrial sheds have purposely less wall window ratio due to their machinery running on the sides and for safety and security reasons also. Area of some of the sheds is so large that the interior areas does not get appropriate amount of light through windows. Hence the main access to natural light in these buildings can be through roof that is through Skylights.

The existing classroom spaces are studied and examined and the best representative classroom are then simulated to check the annual performance and retested with parametric variations such as floor area, orientations, w/o shading devices, size of openings, reflectance of materials, WWR etc. The illuminance levels in the classroom spaces are also measured and compared with the simulation results, to get awareness about the difference real and virtual outcomes. Different dynamic and climate based daylight metrics are evaluated with reference to IES-LM doc and LEED. The data generated from simulation run are then analyzed. Optimal design aspects are identified and observations are made in terms of daylight and design for different variables. More importantly the approach is to provide the suggestive measures towards meeting the criteria of the daylight metrics and to know how they can be achieved and if they fall under the criteria ,why they have achieved it for the given classroom .The research would benefit architects and designers who will in future design any classroom space to achieve the specific daylight metric or if they need to evaluate any space in order to access the daylight performance within the scope of the research.

been evolving from research to reality. Currently, there are only a small number of highly efficient buildings that meet the criteria to be called "Net Zero". As a result of advances in construction technologies, renewable energy systems, and academic research, creating Net Zero Energy buildings is becoming more and more feasible. The idea of net-zero energy building has been in the list of trends in architectural advances for quite some time now. A net-zero energy campus on the other hand emerging phenomenon in India. It is basically the similar approaches that one takes to make a building net-zero energy, but on a larger scale. At the campus level, one can make use of the character of the site. What makes the goal of net-zero energy at a campus level more achievable is the fact that one can always enforce policies to limit use of energy use and hence save energy.

and dry climate of Ahmedabad, was selected and its impact on daylighting in interior spaces is analyzed compared to a no-tree scenario. The distance of the tree from the window was varied to examine parameters such as contrast and brightness at the task plane for the equinox and solstice days. Desktop Radiance 2.0, which is a backward ray tracing daylight simulation software, was used, followed by a calibration study. Uniform and sunny sky conditions based on Ahmedabad climate data were considered. The results indicate that trees can be very effective in achieving visual comfort in conditions of harsh sunshine outdoors. The type of tree is of more importance for visual comfort than the distance between the tree and the window. The evergreen tree performed well to mitigate visual discomfort. Careful selection of the tree type and its positioning on the southern facade reduced illuminance levels but helped improve visual comfort by almost 50%. This study also explains in detail the method used for determination of Leaf Area Index and Leaf Area Density used for calculating the crown density of the tree, which may help future work attempting to study the impact of vegetation on the thermal or visual performance of building envelope.

fixed 45 decibels as the safe noise level for a city, which if exceeded, can cause loss of hearing and irreversible changes in nervous system. On the contrary, the metropolitan cities of India: Mumbai, New Delhi and Chennai have registered an average more than 90 decibels. It is observed that noise forms a major constraint for employing adaptive comfort strategies like use of balconies, opening the window for increased ventilation, etc. due to which a higher discomfort is reported. This study focuses to understand on occupants’ behaviour of opening/closing the windows in residences of India. A Survey will be conducted in Delhi, Mumbai, Ahmedabad and Indore covering minimum 300 residences, to track the reasons responsible for control of windows. In this survey, occupants will be asked to fill up a survey questionnaire on window operation and measurements of temperature, relative humidity and noise levels inside and outside the residence will be taken. Statistical analysis of survey will help bringing out a range of these parameters responsible for window operation under which windows are kept open or closed. The study will also evaluate the energy required in room to achieve comfortable environment inside through mechanical modes of cooling when windows are closed due to unfavourable outside, with the help of a simulation tool in which temperature, humidity and noise levels outside the room will be the input parameters. This study will help tracking the range of temperature, relative humidity and noise levels under which windows can be kept open. Also difference in energy consumption of same space will be identified if kept closed.

of physical conditions, occupant sensations, their behavior as well as the characteristics of the building. The enquiry will be to understand the impact of the building envelope on the indoor thermal environmental conditions. The primary intention of this work is to provide a detailed look at the overall effect of building envelope (building material and construction techniques) on the thermal characteristics of the space. The study includes thermal comfort surveys and simultaneous measurements of indoor environmental variables. The questionnaire for survey is prepared to obtain the subjective responses from the respondents on various thermal comfort parameters such as temperature, humidity and air flow along with a response on overall thermal comfort. Hence, the study would conclude the impact of different construction materials and techniques on the indoor thermal comfort.

and is assessed by subjective evaluation”. In India, we follow a range of temperature based on ASHRAE 55 standard for air conditioned buildings. Many researchers have claimed that this temperature range is narrow and not appropriate for Indian conditions. There are very few studies in the Indian context which have focused on this issue. The study is a part of larger study conducted at CARBSE (Centre for Advanced Research in Building Science and Energy), CEPT University. The study aims to understand the thermal sensation of people working in office buildings lying in hot and dry climate of Ahmedabad, India. Field studies were conducted for two building types i.e., naturally ventilated and air conditioned where thermal comfort votes along with parameters of air movement, clothing, activity levels etc. from occupants using questionnaires were collected. Simultaneously, the indoor environmental conditions were also measured near every occupant. Peak summer (May) and peak winters (January) were chosen for this purpose. In summer, the study was extended to naturally ventilated buildings. This field study was conducted independently by the author. The other surveys were conducted by CARBSE, with author being one of the survey team members. Three buildings were surveyed to understand thermal comfort conditions along with adaptive thermal comfort strategy in this building type. In naturally ventilated buildings, where the mechanical cooling or heating systems are absent, occupants adapt themselves in order to achieve comfort. The study also aims to find a relation between the thermal sensations of people and its variation with building characteristics. The results are compared to the ASHRAE 55 standard for air conditioned as well as naturally ventilated buildings to ascertain its suitability for hot and dry climate.

Jalis are used extensively in Islamic architecture. The physical function of the Jali is to reduce the amount of light admitted inside and to cut out its blinding glare; to allow the passage of air but arrest powerful gusts, which essentially makes it a climate control device for various climates in India. The screens of Islamic architecture represent the best examples attesting to this observation. In this study about 256 stone Jalis of 30 Islamic mosques in Ahmedabad city (23° 1? N, 72° 34? E; hot and dry climate) built during 13th to 16th century were studied and documented. Frame size, solid/void ratio, height-of-void / thickness of Jali ratio were recorded. Based on this documented data 27 representative Jalis, (simplified geometry, without ornamentation) of 250mm x 250 mm frame size, were prepared for 3 different thicknesses, 3 different solid/void ratios, and 3 height-of-void / thickness of Jali ratio. These representative Jalis were simulated in Radiance 1.02 for different times of the day in four orientations. Radiance is a suite of tools for performing lighting simulation which works on backward ray-tracing. The simulation results revealed that the thickness and depth of the stone Jali played an important role in blocking direct sun light, providing uniform daylight, and preventing glare, for the location of Ahmedabad.

the parent company. Sick building syndrome was one of the main reasons for creation of new field in science called “Thermal Comfort”. Hence, thermal comfort models were developed to help the architects and other building engineers in design process. There are different models like Fanger and Adaptive for defined the comfort zone; may it be static or dynamic. Though based on established studies and related research, it has been successfully proved that adaptive model of thermal comfort is better applicable than the static model, most of the offices in the national capital region of India still use static model of thermal comfort (ASHRAE 55 – 1999). It may be explained on the basis of lack of field studies on thermal comfort to benchmark the present perception of the occupants in real conditions or on the basis of fact that the national building code of India still propagates the static model of comfort. Hence the main objective of this research is to evaluate thermal comfort of occupants in air conditioned office spaces in national capital region of India. It is carried out by evaluating the present state of thermal comfort in the office setups of 12 multinational corporations in the region. The evaluation is carried out by directly relating the onsite comfort parameters (air temperature, relative humidity and air velocity) to the comfort votes given by the occupants.

of variables such as floor area, aspect ratio, glazing/window area, orientation, glazing types and overhang has been observed on the building lighting and cooling loads using parametric simulation. The data generated from simulation run is then analyzed using Multiple Regression Analysis to express loads as a function of floor area, aspect ratio and orientation of windows. A near optimal window is identified and observations are made in terms of trade-offs between lighting and cooling load savings for different variables.

hence there is a need to find effective design measures to develop energy efficient buildings. Courtyard is a traditional design measure which can be used in reducing energy consumption of the buildings. It has been seen in Indian cities often, the current urban development plan is trying to integrate courtyards in the design of buildings. However what would be the effect of incorporating courtyards in the energy consumption of commercial buildings, also to what extend would courtyards help within the limitations of building by laws and varying site proportions of new master plans in Indian cities. The study focuses on the effect of courtyard form with different proportions, wall to window ration (WWR) and overhangs on the thermal performance of the commercial buildings. The hypothetical model of courtyard building configurations depends on available urban schemes (site proportions) and building by laws (Setbacks, Ground Coverage and Floor Area Ratio). For varying building heights, different hypothetical building configurations have been derived, on which various WWR and overhangs have been applied. The computer energy simulation program DesignBuilder Version 2.04.002 was used in this study as a simulation tool to evaluate the impact of these parameters on the thermal performance of the buildings. The result of the simulation showed that the courtyard building thermal performance differed from various configurations. In general, determining the relative qualities of the configuration versus another specific proportions is difficulty and also introducing a courtyard in a building is not always an acceptable solution unless it’s all parameters are not proficiently used. This study assisted in understanding the difficulties of courtyard building configuration to its maximum potential for new commercial architecture in hot-dry climate of India.

tool. The study establishes itself on this premise. The exercise elaborates evaluating the impact of vertical and horizontal planar interior elements’ surface reflectance & examines its impact on LPD. This is done through different scenarios derived from the base case. All derived scenarios were then confirmed to the established standard of visual comfort. The result was collated to develop a chart illustrating the finding.