Abstract

Fault detection and diagnostics (FDD) is a method to monitor a system, identify when a fault has occurred, and point out the type of fault and its location. This method improves comfort, and reduces the operation, maintenance, and utility costs, thus reducing the environmental impact. In this paper, the design of FDD lab is presented where a user can create different types of faults in Heating, Ventilation and Air-conditioning (HVAC) systems, and develop and test algorithms for the detection and diagnostics of faults. This facility will help identify and analyse the faults pertaining to HVAC systems that are prevalent in India nowadays.

Abstract

Field study of thermal comfort was conducted in six naturally ventilated hostel buildings of composite climate considering Class-II protocol of field measurement during summer 2011. Total 429 survey samples of same age group (average 19.6 years) were collected including objective and subjective measurements. Statistical analysis of student's responses and measured thermal environment variables was performed to determine existing indoor environmental conditions and priority of using behavioural controls. Thermal comfort indices were also calculated and compared to the student's perceptions. Neutral temperature was found to be 30.15 °C through regression analysis, with an average clothing of 0.41 Clo (min. 0.19 Clo, max 0.82 Clo). Results have shown a wide bandwidth of neutral temperatures (25.9–33.8 °C) for the hostel buildings which is higher than national/international standards of thermal comfort …

Abstract

Thermal comfort in building results from a complex set of physical conditions, occupant sensations and preferences as well as occupants behaviour therefore thermally comfortable environment leads to better energy efficiency in buildings. A field study was carried out at five star rated (Certified by Bureau of Energy Efficiency, BEE) air conditioned office building (day time occupancy) located at Jaipur, composite climate of India. The purpose of conducting this study was to evaluate the existing thermal environmental conditions and then to propose the required thermal comfort conditions and determine energy saving potential considering adaptive thermostat control strategy. Questionnaire was developed for conducting the field survey including objective and subjective information as per class˗ II protocol of field measurements. Statistical analysis of occupant responses and recorded environmental variables was performed to determine the required comfortable temperature in the building and this temperature was used as thermostat set point of the air conditioner. The office building was modelled using eQUEST simulation program and calibrated with measured annual energy consumption. Result revealed that majority of the occupants felt thermally comfortable at proposed room temperature of 27.5oC as against the existing practice of maintaining 20-22oC at which most of the occuapants were complaining overcooling and discomfort. Proposed set point temperature of air conditioner also resulted in building energy saving of about 7.86%.

Abstract

This study evaluates improvement in energy efficiency of an air conditioned building block employing energy conservation measures (ECMs) recommended by Indian Energy Conservation Building Code 2007 (ECBC) through a prescriptive route. First part evaluates energy savings by implementing five ECMs of envelope independently and two combinations of ECMs keeping constant thermostat setting throughout the year. In the second part of the study same ECMs are considered to the subject building model allowing thermostat settings as per thermal adaptation resulting from change in outdoor temperature. Actual measurements were taken and simulation model was fine-tuned. Annual energy consumption of building is used to evaluate the effect of individual ECMs and their combinations on both part of the study, i.e. fixed thermostat and adaptive thermostat settings. The simulation result shows that together …

Abstract

We evaluate differences in clear-sky upwelling shortwave radiation reaching the top of the atmosphere in response to increasing the albedo of roof surfaces in an area of India with moderately high aerosol loading. Treated (painted white) and untreated (unpainted) roofs on two buildings in northeast India were analyzed on five cloudless days using radiometric imagery from the IKONOS satellite. Comparison of a radiative transfer model (RRTMG) and radiometric satellite observations shows good agreement (R 2= 0.927). Results show a mean increase of~ 50 W m− 2 outgoing at the top of the atmosphere for each 0.1 increase of the albedo at the time of the observations and a strong dependence on atmospheric transmissivity.

Abstract

Cool roofs, cool pavements, and urban vegetation reduce cooling energy use in buildings, lower local air pollution, and decrease greenhouse gas (GHG) emissions from urban areas. To promote widespread and large-scale implementation of cool roofs to moderate urban heat-island phenomenon, more awareness and understanding of cool roof benefits at the local level is needed. As part of an investigation of strategies to mitigate urban heat-island effects, field data gathered from a monitoring project on cool roofs in India were reviewed. An innovative field-based analytical method was developed to quantify cooling energy savings resulting from the installation of cool roofs on commercial buildings. For buildings monitored in the Metropolitan Hyderabad region, the measured annual energy savings from roof-whitening of previously black roofs ranged from 20 to 22 kWh/m2 of roof area, corresponding to a cooling …

Abstract

The thermostat control variable in conventional HVAC System is air temprature Ta

Abstract

The study, conducted in composite climate of India, exhibits improvement in energy efficiency of a conditioned building block with the use of energy conservation measures (ECMs) recommended by National Energy Conservation Building Code (ECBC). In first part of it, subject building model was individually applied with five ECMs and two combinations of these ECMs by using constant thermostat settings. Similarly in second part of the study the same was done with adaptive thermostat settings. Sensitivity analysis showed that the effect of ECMs get reduced with increase in building footprint and internal loads. Analysis of thermal comfort in an unconditioned building using same set of ECMs was also carried out to see improvement in comfort hours.

Abstract

This article presents an approach for speeding EnergyPlus simulations. The computing run time of an energy simulation depends on several variables and is directly proportional to the simulation RunPeriod. In the proposed approach, data parallelization is achieved by breaking an annual simulation into several segments of smaller RunPeriod, each handled by a separate computer/processor. The speed gain achieved by running 12 one-month RunPeriod segments in parallel as compared to single simulation of 12 months is between three and six times. Segmentation of simulation has resulted in minor deviations between the results obtained through segmented simulations and annual simulations. Methods for reducing these deviations on annual and monthly basis are presented in this article using 12 benchmark models each simulated for five cities. On annual basis, a maximum deviation of 0.06% was observed …

Abstract

Cool roof is one of the important strategies of energy savings in the tropical climate especially for low rise buildings. Standardization of the possible energy savings for a measure like cool roof would be quite difficult due to availability of various technologies and materials, as well as due to difference in building forms and climatic conditions. This paper talks about the development of an online tool for estimating energy saving through cool roof strategy using Energy Plus v4 as the backend simulation engine. Energy savings are calculated through simulating two identical buildings with different roof reflectivity values. Using this tool, simulations are run for the base case roof reflectivity of 0.3 and proposed case roof reflectivity of 0.75 for various major cities in India for a single floor, daytime use building. An average saving of 6.2% in cooling energy and 2.4% in total energy consumption was obtained using this tool.