Abstract

Increasing roof reflectance reduces absorption of solar radiation, roof surface temperature and heat ingress into the building. This leads to an increase in indoor comfort and reduction in room air temperature that in turn results in energy saving by reducing AC demand. To assess this impact of cool roofs on buildings in rural and peri-urban areas of India, a study was performed on two un-conditioned school buildings in Hyderabad (ZPH School) and Nagpur (VNHM School). Two classrooms of same size, function, and occupancy from both the school buildings were monitored for a period of ten weeks starting from March 2014 till May 2014. The data from the experiments and their analyses showed promising results. The average reduction and peak reduction in indoor air, roof underdeck and roof overdeck surface temperatures are 2.1 ◦C, 5.0 ◦C and 12.3 ◦C and 4.3 ◦C, 10.0 ◦C and 26.3 ◦C respectively for the room with white roof as opposed to grey roof in ZPH School and 1.5 ◦C, 4.0 ◦C and 9.5 ◦C, and 3.3 ◦C, 4.2 ◦C, and 25.2 ◦C respectively in VNHM School. The results from the experiment prove that white roof has a significant effect in reducing the indoor air temperatures in buildings due to reduction in outdoor and indoor roof surface temperature

Abstract

In tropical countries such as India, increasing the roof albedo helps to reduce the heat ingress through the roof. This further reduces air-conditioning energy consumption in conditioned buildings and increases comfort in unconditioned buildings. In order to help users determine the benefits of high albedo roofs under varying conditions, a simple calculator has been developed. Parameters such as location, building type, roof area, and surface properties of the roof are taken as inputs. Annual EnergyPlus simulations are performed for the given parameters and the results are displayed in both graphical and tabular formats. It also calculates the simple payback by comparing a given base case roof albedo with the proposed roof albedo. The calculator can perform comfort simulations for unconditioned buildings and simulates measures including a radiant barrier system and under deck roof insulation. The calculator also runs a parametric simulation between insulation thickness and roof albedo to find an optimum roof insulation thickness based on incremental internal rate of return. This paper presents the features of the cool roof calculator and the type of analysis that can be performed using the cached results.

Abstract

Energy utilization can be improved by precise plug load monitoring and control. Plug load energy consumption is nearly 30% of the total building energy consumption. Therefore, plug load identification is a key requirement for energy conservation in buildings. Intrusive load monitoring techniques identify loads precisely but have not been tested widely so far for their performance in changing operating conditions. Hence, the present research proposes a robust low frequency intrusive load monitoring technique to identify load accurately. A smart power strip using proposed load identification technique is designed and developed. Linear regression is applied on the acquired data to capture the behavioral trends of a particular device more explicitly and concisely. Further, weighted K-NN classifier is applied on the transformed data set for device. Experimental results show that the proposed algorithm performs better than the standard classifiers, and can offer tangible savings.

Abstract

Plug loads accounts for 20% to 30% of building energy consumption and has an increasing trend. Automatic plug load identification is one of the technique for effectively managing the plug load consumption.There are several studies on Non Intrusive load monitoring (NILM) but limited studies on Intrusive load monitoring (ILM). ILM is a technique that uses a low end power meter on every plug load to monitor it’s power consumption. In this paper, machine-l earning techniques are applied on low-frequency ILM data for identification of plug load and it’s state (ON/Sleep).The results show the identification accuracies are close to 98%

Abstract

To make roofs energy efficient, typically two types of techniques are followed: surface treatments (coolroofs, radiant barriers) and thermal property modifications (roof insulation). The interplay between thesetwo techniques has been studied using energy simulations. A single storey, daytime operational, officebuilding of 200 m2area has been simulated forfive climatic zones in India. A total of 88 different roofcombinations have been studied for each climatic zone. An economic analysis using Internal Rate ofReturn has been performed to identify a suitable roof insulation thickness for a roof with high albedo,and radiant barrier combination. The incremental benefits in energy savings reduces by adding insulationafter a limit. For a roof with albedo of 0.6 and radiant barrier emittance of 0.2, the optimized roofR-valueis 0.49 m2K/W in hot and dry and composite climates, 0.31 m2K/W in warm and humid and temperateclimates, and 1.02 m2K/W for cold climates

Abstract

SURROGATE CITY FINDER - WEATHER DATA TOOLVishal Garg, T.V.S Nikhil, Hema Rallapalli,Aviruch Bhatia, Jegibabu Subhash, Chetan Kasireddy International Institute of Information Technology, Hyderabad, India. ABSTRACTWeather data is the one of the important inputs for the building energy simulation and is available for almost all major cities of the world. However, there are still some cities, for which weather data is not readily available in the format suitable for energy simulation. To address this problem, we have developed a web-based tool called Surrogate City Finder (SCF). For a given location, for which there is no weather file available, the tool shortlists the best-matched weather files based on parameters such as the latitude, altitude, and temperature range of the given location. The SCF tool has been tested by analysing the annual energy consumption of 16-reference building models simulated for eight locations from different international climate zones and their surrogate cities. In most cases, the deviation in annual energy consumption was within two percent.

Abstract

In order to help architects and designers make early design decisions, an online tool (WinOpt) has been developed. WinOpt optimizes various components associated with the design of windows such as Azimuth Angle (angle with respect to North), Aspect Ratio, WWR (Window Wall Ratio), SHGC (Solar Heat Gain Coefficient) of glass used for windows, and various local shading strategies such as overhang and side fins. WinOpt performs annual energy simulations for a given location using EnergyPlus. It uses an optimization tool in the back end (GenOpt) to reduce the few million simulations to a few hundred, thus helping in making perfect rapid design decisions. WinOpt optimizes the design to minimize the operational energy for conditioned buildings and maximize thermal comfort for unconditioned buildings. It also has a parametric option where parametric simulations are performed for selected values for various input parameters. This can help the user understand the spectrum of design solutions. Since EnergyPlus can evaluate thermal comfort conditions besides energy consumption in a building, WinOpt can help in design decisions for low energy/ net zero energy buildings.

Abstract

The electric load of an office building can be classified into lighting load, HVAC load, and plug load. Monitoring the lighting and HVAC load is relatively simple. However, the product range of plug load devices is diverse and their usages vary considerably making it difficult to understand plug load usage and consumption. Plug loads account for more than 20 percent of energy consumption in a building. Even though the share of plug load in building energy is increasing, very few studies exist on the device level energy usage and consumption in an academic institution in India. Therefore, the study of plug load is done to gain insight on their usage and energy consumption patterns. A total of 93 energy meters were installed on a sample of plug load devices. For each connected device, the current, voltage, and accumulated power are logged along with the timestamp for a period of 4 months. Different analysis like estimation of annual energy usage, average load profiles on different day types, variability in energy consumption among devices and so on were performed. Based on the analysis, the study recommends strategies to reduce plug load consumption and also suggests load schedules which can be used in energy simulation for realistic energy results.

Abstract

This article presents the effect of envelope measures on thermal environmental conditions of a naturally ventilated building block in composite climate of India. Envelope measures such as roof U-value, wall U-value, glass U-value and glass solar heat gain coefficient, roof reflectance and two combinations of these measures (total seven cases) are analysed as recommended by National Energy Conservation Building Code-India (ECBC) through prescriptive route. Subject building is modelled and simulated using dynamic thermal simulation tool. Two approaches of thermal comfort have been used in this study such as heat balance model based on laboratory study and adaptive model of thermal comfort based on field findings. Thermal environmental conditions are evaluated based on operative temperature with and without considering the effect of thermal adaptation. This study found that comfortable temperature …

Abstract

Increasing roof reflectance reduces absorption of solar radiation, roof surface temperature and heat ingress into the building. This leads to an increase in indoor comfort and reduction in room air temperature that in turn results in energy saving by reducing AC demand. To assess this impact of cool roofs on buildings in rural and peri-urban areas of India, a study was performed on two un-conditioned school buildings in Hyderabad (ZPH School) and Nagpur (VNHM School). Two classrooms of same size, function, and occupancy from both the school buildings were monitored for a period of ten weeks starting from March 2014 till May 2014. The data from the experiments and their analyses showed promising results. The average reduction and peak reduction in indoor air, roof underdeck and roof overdeck surface temperatures are 2.1 ◦C, 5.0 ◦C and 12.3 ◦C and 4.3 ◦C, 10.0 ◦C and 26.3 ◦C respectively for the room with white roof as opposed to grey roof in ZPH School and 1.5 ◦C, 4.0 ◦C and 9.5 ◦C, and 3.3 ◦C, 4.2 ◦C, and 25.2 ◦C respectively in VNHM School. The results from the experiment prove that white roof has a significant effect in reducing the indoor air temperatures in buildings due to reduction in outdoor and indoor roof surface temperature.