Assessing annual thermal comfort extent in central courtyards : Baghdad as a case study

Purpose: Traditional central courtyards have been advocated for being thermally efficient for hot-climate regions. However, exploring previous literature shows that it is not clear to what extent courtyards are truly thermally comfortable. This study determines the level of thermal comfort in residential courtyards in hot-climate regions, taking Baghdad as a case study. Design/methodology/approach: This study develops a novel Courtyard Thermal Usability Index (CTUI) to quantify the ability of courtyards to provide thermal comfort to occupants. CTUI is the fraction of useable thermally comfortable hours in courtyards of the total occupation hours during a specific period. To operationalise CTUI, the research employs the Envi-met 4.2 simulation tool to determine the annual thermal conditions of 360 courtyards. An adaptive thermal comfort model developed by Al-Hafith in 2020 for Iraq is used to judge simulated thermal conditions and determine CTUI. Findings: CTUI enables determining the level of thermal comfort courtyards offer to occupants by showing the ratio of the thermally comfortable period versus the occupation period. Results show that, in Iraq, annually, courtyards offer up to 38% comfortable hours out of the total potential occupation hours. The rest of the time the courtyard will not be comfortable, mostly due to overheating. When designing courtyards, the most effective geometric property impacting courtyards' thermal conditions is width/height. The most important microclimatic factor impacting occupants' thermal sensation is mean radiant temperature (MRT). This study can be used to inform designing thermally efficient courtyards for hot-climate regions. Originality/value: This study presents the first assessment of the thermal efficiency of courtyards in hot-climate regions depending on an assessment of their ability to provide thermal comfort to occupants. The study presents a novel index that can be used to quantify the ability of courtyards to provide a thermally comfortable environment to occupants

Patterns of thermal preference and Visual Thermal Landscaping model in the workplace

The main purpose of research on occupant behaviour is to enhance building energy performance. However, it is difficult to reduce the energy use without understanding the occupant, their needs and preferences. Individual differences and preferences for the thermal environment in relation to the spatial context are overlooked in the main stream of research. This study investigates the patterns of occupant thermal preference based on individual differences in perceiving the thermal environment to enhance user comfort and energy performance. A novel method of Visual Thermal Landscaping is used, which is a qualitative method to analyse occupant comfort and user behaviour according to the spatial context. This method drives away from the notion of ‘thermal neutrality’ and generic results, rather it opens to details and meaning through a qualitative analysis of personal-comfort, based on individual differences and spatial context information. Field test studies of thermal comfort were applied in five office buildings in the UK, Sweden and Japan with overall 2,313 data sets. The primary contribution of the study was the recognition of four patterns of thermal preference, including consistent directional preference; fluctuating preference; high tolerance and sensitive to thermal changes; and high tolerance and not-sensitive to thermal changes. The results were further examined in a longitudinal field test study of thermal comfort. In several cases, occupant thermal comfort and preferences were observed to be influenced by the impact of outdoor conditions, when the windows were fixed. Practical solutions for research, practice and building design were recommended with direct implications on occupant comfort and energy use

Performance Characteristics of Indigenously Developed 24-Bit Seismic Data Recorder for Earthquake Seismology

This paper describes long term performance of CSIO developed seismic data acquisition tested on local, regional and distant earthquakes in comparison with imported data acquisition system. Waveform data is cross-correlated to test the similarity and validate the results. Two major earthquakes have been considered for cross-correlation procedure and the results have been analyzed and explained. CSIO developed 24-bit seismic data recorder has been explained

Characteristic evolution of indigenously designed and developed tri-axial force balanced accelerometer

This paper describes indigenously designed and developed tri-axial Force Balanced Accelerometer (FBA) using variable capacitance transduction and electromagnetic feedback. Accelerometer is a highly sensitive, low frequency seismic sensor characterized by rugged construction and proven reliability. It has been designed and developed for ±1g full-scale range with 50 Hz natural frequency mainly for seismic, structural, aerospace and some commercial applications. In a single unit, three accelerometers are orthogonally mounted on a plate and housed in a case for recording all the three components of motion. Characteristics evolution of a natural frequency, damping and noise level, have been done, tested and explained. During designing, most of the technical specifications have been considered for low frequency band from DC to 200Hz applications. Accelerometer is suitable for strong motion recording purpose

Design improvements in digital seismograph for recording long duration seismic events & after shocks

The paper highlights a new design approach to overcome technical limitations of digital seismographs by incorporating optimum hardware and efficient software modules etc. The paper illustrates how the new design approach has enhanced the limited 64 kbytes addressing capability of 8-bit microprocessor based seismograph to 16 Mbytes capacity. Instrument based on this design philosophy can now record many long duration seismic events and the series of subsequent aftershocks, which need storage of several mega bytes. The technique has enabled uninterrupted data acquisition and processing even when the data of earlier recorded events is being transferred from main storage to PC hard disk. The design concept has been validated successfully by operating the instrument based on this technique for long time in the field

24 bit seismic processor for analyzing extra large dynamic range signals for early warning.

Modified design is presented of existing 24 bit seismic data recorder comprising PC –architecture using PCI bus, ISA bus, and PC 104 bus in a single module to develop a flexible measurement set up. Paper elaborates use of building blocks [Disk on chip (DoC), GPS based timing unit, signal-processing module, and efficient software packages] worked out in visual C++ to develop compact sized instrument for quick decision-making with minimum error detection of true events. Paper describes Ethernet connectivity use for data downloading in a laptop without interruption of event data acquisition. Software packages for conversion of recorded data into SUDS and SEISAN formats have been realized and incorporated

Rainfed Technologies For Karnataka

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Suitable Dryland Technologies For Karnataka(Kannada version)

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