This study investigated thermal comfort and adaptive behaviors of university students in classrooms in Malaysia and Japan during the summer season. Indoor environmental conditions and students' thermal perceptions were measured in classrooms with both mechanical cooling and natural ventilation. A total of 1428 students from three universities participated. The results showed that average comfortable temperatures were similar between the two countries, around 25-26°C, and generally aligned with international comfort standards. While most students reported taking no actions to adjust their comfort, changing the air conditioning settings was a common behavior among Malaysian students where mechanical cooling was prevalent.
Modeling climate phenomenon with software grids analysis and display system i...journalBEEI
This study aims to model climate change based on rainfall, air temperature, pressure, humidity and wind with grADS software and create a global warming module. This research uses 3D model, define, design, and develop. The results of the modeling of the five climate elements consist of the annual average temperature in Indonesia in 2009-2015 which is between 29oC to 30.1oC, the horizontal distribution of the annual average pressure in Indonesia in 2009-2018 is between 800 mBar to 1000 mBar, the horizontal distribution the average annual humidity in Indonesia in 2009 and 2011 ranged between 27-57, in 2012-2015, 2017 and 2018 it ranged between 30-60, during the East Monsoon, the wind circulation moved from northern Indonesia to the southern region Indonesia. During the west monsoon, the wind circulation moves from the southern part of Indonesia to the northern part of Indonesia. The global warming module for SMA/MA produced is feasible to use, this is in accordance with the value given by the validate of 69 which is in the appropriate category and the response of teachers and students through a 91% questionnaire.
Current Issue: April 2019, Volume 6, Number 1 --- Table of Contentsijcax
The purpose of this research is the analysis using meta-analysis of studies in the field of Educational Technology in Turkey and in the field is to demonstrate how to get to that trend. For this purpose, a total of 263 studies were analyzed including 98 theses and 165 articles published between 2010-2018. Purpose
sampling method was used when selecting publications. In the research, while selecting articles and theses; Turkey addressed; YOK Tez Tarama Database, Journal of Hacettepe University Faculty of Education, Educational Sciences : Theory & Practice Journal, Education and Science Journal, Elementary Education
Online Journal, The Turkish Online Journal of Education and The Turkish Online Journal of Educational Technology used in journals. Publications have been reviewed under 11 criteria. Index, year of publication, research scope, method, education level, sample, number of samples, data collection methods,
analysis techniques, and research tendency, research topics in Educational Technology Research in Turkey has revealed. The data is interpreted based on percentage and frequency and the results are shown using the table.
IRJET- Energy Saving in Governmental Educational Buildings: Case StudyIRJET Journal
This document presents a case study on implementing energy saving methods in an educational building in Egypt. Two methods are analyzed: 1) Replacing fluorescent lamps with LED lamps. This is estimated to save 21.8% of energy annually based on a simulation. 2) Installing sensors for smart energy control, estimated to save an additional 20% of energy. Together the two methods could save 41.8% of energy annually and pay for themselves within 3 years. Practical installations in a lecture hall and office showed improved lighting and reduced energy consumption compared to fluorescent lamps. Overall the study finds that replacing lamps with LEDs and adding smart controls can significantly reduce energy use and costs in this type of building.
The utilization of conventional sources of energy releases harmful pollutants to the environment causing global warming and acid rain. For that reason, it becomes necessary to use a non-depletable, sustainable and eco-friendly renewable energy as a mean of producing electricity. Malaysia is tropical country rich in resources beneficial in electricity generation as it is in equatorial region therefore it has an abundance of solar irradiance of average annually. In addition, Malaysia’s demand in electricity is increasing to 124,677 GWh by 2020. Therefore, the electricity generation from renewable sources in Malaysia is anticipated to grow in the future alongside the government endorsement due to its clean, eco-friendly and free source of energy which can highly reduce the dependency on oil and gas that emits harmful pollutants to the environment. This paper gives a comprehensive review on the renewable projects and researches in Malaysia, challenges that affect popularity of renewable energy in Malaysia and available and successful renewable energy system in Malaysia.
The document discusses using solar chimneys to reduce heating loads in cold climates. It summarizes previous research on solar chimneys and their impact on ventilation. The author models a school building in a cold climate with and without a solar chimney using energy simulation software. The results show that with a solar chimney, the indoor temperature reached 22°C without mechanical heating, within the comfort range. By applying passive solar techniques like solar chimneys, architectural projects can save energy without large costs.
1. The document discusses the principles of bioclimatic architecture and how double skin facades (DSF) can help achieve the goals of bioclimatic design.
2. It outlines key principles of bioclimatic architecture like thermal comfort, natural lighting and ventilation and explains how DSF systems incorporate these principles through features like a ventilated facade, shading devices and natural ventilation capabilities.
3. The paper aims to show how DSF design can be a convincing tool for architects by meeting the energy efficiency goals of bioclimatic architecture in areas of daylight, thermal comfort and natural ventilation.
Proper ventilation in one of the primary requirements of any domestic or commercial buildings. The conventional method employs usage of air conditioning or air cooling systems which requires high power consumption. The solar driven ventilation systems can be used in buildings which doesn’t require any external power. The current research reviews various researches conducted in improving system of passive ventilation along use of phase change material as energy storage system. Passive design of buildings does not use the electrical and mechanical systems in providing comfortable indoor environment. Prem Shankar Sahu | Praveen Kumar | Ajay Singh Paikra "Review on Solar Chimney Ventilation" Published in International Journal of Trend in Scientific Research and Development (ijtsrd), ISSN: 2456-6470, Volume-5 | Issue-4 , June 2021, URL: https://www.ijtsrd.compapers/ijtsrd42427.pdf Paper URL: https://www.ijtsrd.comengineering/mechanical-engineering/42427/review-on-solar-chimney-ventilation/prem-shankar-sahu
Modeling climate phenomenon with software grids analysis and display system i...journalBEEI
This study aims to model climate change based on rainfall, air temperature, pressure, humidity and wind with grADS software and create a global warming module. This research uses 3D model, define, design, and develop. The results of the modeling of the five climate elements consist of the annual average temperature in Indonesia in 2009-2015 which is between 29oC to 30.1oC, the horizontal distribution of the annual average pressure in Indonesia in 2009-2018 is between 800 mBar to 1000 mBar, the horizontal distribution the average annual humidity in Indonesia in 2009 and 2011 ranged between 27-57, in 2012-2015, 2017 and 2018 it ranged between 30-60, during the East Monsoon, the wind circulation moved from northern Indonesia to the southern region Indonesia. During the west monsoon, the wind circulation moves from the southern part of Indonesia to the northern part of Indonesia. The global warming module for SMA/MA produced is feasible to use, this is in accordance with the value given by the validate of 69 which is in the appropriate category and the response of teachers and students through a 91% questionnaire.
Current Issue: April 2019, Volume 6, Number 1 --- Table of Contentsijcax
The purpose of this research is the analysis using meta-analysis of studies in the field of Educational Technology in Turkey and in the field is to demonstrate how to get to that trend. For this purpose, a total of 263 studies were analyzed including 98 theses and 165 articles published between 2010-2018. Purpose
sampling method was used when selecting publications. In the research, while selecting articles and theses; Turkey addressed; YOK Tez Tarama Database, Journal of Hacettepe University Faculty of Education, Educational Sciences : Theory & Practice Journal, Education and Science Journal, Elementary Education
Online Journal, The Turkish Online Journal of Education and The Turkish Online Journal of Educational Technology used in journals. Publications have been reviewed under 11 criteria. Index, year of publication, research scope, method, education level, sample, number of samples, data collection methods,
analysis techniques, and research tendency, research topics in Educational Technology Research in Turkey has revealed. The data is interpreted based on percentage and frequency and the results are shown using the table.
IRJET- Energy Saving in Governmental Educational Buildings: Case StudyIRJET Journal
This document presents a case study on implementing energy saving methods in an educational building in Egypt. Two methods are analyzed: 1) Replacing fluorescent lamps with LED lamps. This is estimated to save 21.8% of energy annually based on a simulation. 2) Installing sensors for smart energy control, estimated to save an additional 20% of energy. Together the two methods could save 41.8% of energy annually and pay for themselves within 3 years. Practical installations in a lecture hall and office showed improved lighting and reduced energy consumption compared to fluorescent lamps. Overall the study finds that replacing lamps with LEDs and adding smart controls can significantly reduce energy use and costs in this type of building.
The utilization of conventional sources of energy releases harmful pollutants to the environment causing global warming and acid rain. For that reason, it becomes necessary to use a non-depletable, sustainable and eco-friendly renewable energy as a mean of producing electricity. Malaysia is tropical country rich in resources beneficial in electricity generation as it is in equatorial region therefore it has an abundance of solar irradiance of average annually. In addition, Malaysia’s demand in electricity is increasing to 124,677 GWh by 2020. Therefore, the electricity generation from renewable sources in Malaysia is anticipated to grow in the future alongside the government endorsement due to its clean, eco-friendly and free source of energy which can highly reduce the dependency on oil and gas that emits harmful pollutants to the environment. This paper gives a comprehensive review on the renewable projects and researches in Malaysia, challenges that affect popularity of renewable energy in Malaysia and available and successful renewable energy system in Malaysia.
The document discusses using solar chimneys to reduce heating loads in cold climates. It summarizes previous research on solar chimneys and their impact on ventilation. The author models a school building in a cold climate with and without a solar chimney using energy simulation software. The results show that with a solar chimney, the indoor temperature reached 22°C without mechanical heating, within the comfort range. By applying passive solar techniques like solar chimneys, architectural projects can save energy without large costs.
1. The document discusses the principles of bioclimatic architecture and how double skin facades (DSF) can help achieve the goals of bioclimatic design.
2. It outlines key principles of bioclimatic architecture like thermal comfort, natural lighting and ventilation and explains how DSF systems incorporate these principles through features like a ventilated facade, shading devices and natural ventilation capabilities.
3. The paper aims to show how DSF design can be a convincing tool for architects by meeting the energy efficiency goals of bioclimatic architecture in areas of daylight, thermal comfort and natural ventilation.
Proper ventilation in one of the primary requirements of any domestic or commercial buildings. The conventional method employs usage of air conditioning or air cooling systems which requires high power consumption. The solar driven ventilation systems can be used in buildings which doesn’t require any external power. The current research reviews various researches conducted in improving system of passive ventilation along use of phase change material as energy storage system. Passive design of buildings does not use the electrical and mechanical systems in providing comfortable indoor environment. Prem Shankar Sahu | Praveen Kumar | Ajay Singh Paikra "Review on Solar Chimney Ventilation" Published in International Journal of Trend in Scientific Research and Development (ijtsrd), ISSN: 2456-6470, Volume-5 | Issue-4 , June 2021, URL: https://www.ijtsrd.compapers/ijtsrd42427.pdf Paper URL: https://www.ijtsrd.comengineering/mechanical-engineering/42427/review-on-solar-chimney-ventilation/prem-shankar-sahu
Understanding Trend and Variation of Electrical Energy usage Among Students i...ijtsrd
The National University of Malaysia UKM is one of the prestige public university in Malaysia. Therefore, the University's management is always proactive in planning the best student facilities every year. The growth in electricity consumption and demand, however, has increased. Hence, this study aims to look at the comparison trend of electricity consumption of several colleges at Universiti Kebangsaan Malaysia and the daily consumption rate of electricity used. Generally, this study is based on a quantitative scientific exploration study where energy consumption information is measured based on actual records between August and October 2017. In addition, observation on energy consumption of the student is also conducted. The findings show that the range of utility cost ratio with the total of students is between 49.5 kWh student and 80.8 kWh student and the average energy consumption is around 65.2 kWh student. The findings reveal that there is an imbalanced in the trend of energy consumption among the college dwellers. Responses from the Khazanah and college management revealed the necessity to study in depth in particularly the operation and management factors that may have an impact on these significant differences. Generally, the findings of random observations in UKMs campus residential colleges have found that a small percentage of students do not concerned on energy savings. Electricity awareness and savings campaigns should be one of the students activities in the colleges. In addition, the Universitys managers also need to think of a comprehensive action plan that is in line with the needs of sustainable or green campus in the future. Noorazuan Md Hashim | Muhammad Khaidir Bin Azmi | Yaakob Mohd Jani "Understanding Trend and Variation of Electrical Energy usage Among Students in the National University of Malaysia" Published in International Journal of Trend in Scientific Research and Development (ijtsrd), ISSN: 2456-6470, Volume-3 | Issue-3 , April 2019, URL: https://www.ijtsrd.com/papers/ijtsrd21586.pdf
Impact of Building Envelope Modification on Energy Performance of High-Rise A...drboon
This document summarizes a research study that investigated the impact of building envelope modifications on the energy performance of high-rise apartments in Kuala Lumpur, Malaysia. Three high-rise apartment buildings were modeled using EnergyPlus software to analyze the effects of thermal insulation and glazing type on potential energy savings. The study found that integrating passive envelope design measures like improved insulation and higher performing glazing could help reduce energy consumption and peak cooling loads in the apartments. Modifying elements of the building envelope, especially the walls and windows, may enable significant energy savings potential for high-rise residential buildings in hot and humid climates.
This document discusses natural ventilation in residential buildings in hot-humid climates like Malaysia. It notes that while energy efficient cooling strategies have been implemented to reduce dependency on non-renewable energy, natural ventilation is a passive strategy that can provide thermal comfort while saving energy. Previous studies on occupants' ventilation behavior have shown that occupants prefer natural ventilation over mechanical systems. However, more research is needed on ventilation behavior in individual living spaces and under different house designs in hot-humid climates. The document aims to investigate natural ventilation provisions and occupants' utilization of openings in different terrace house designs in Malaysia, and factors that influence occupants' satisfaction with indoor ventilation when using natural ventilation.
A scholarly review on revealing the influence of unforeseen sub-factors in th...IRJET Journal
This document summarizes a scholarly review on the influence of unforeseen sub-factors on adaptive thermal comfort in classrooms of primary and secondary schools. It finds that in addition to the four main factors of thermal comfort prescribed by standards (air temperature, radiant temperature, metabolic rate, clothing insulation), other sub-factors like age, gender, season, local climate, socioeconomic status, adaptive behaviors, passive cooling/heating, building features and orientation also influence thermal comfort. Through an analysis of 54 studies from the last 15 years, it was found that seasonal changes, adaptive behaviors like clothing and window/fan use, and socioeconomic factors impact children's thermal comfort more than adults. A holistic approach is needed to fully understand
Energy Audit and Analysis of an Institutional Building under Subtropical Clim...IJECEIAES
Evaluation and estimation of energy consumption are essential in order to classify the amount of energy used and the way it is utilized in building. Hence, the possibility of any energy savings potential and energy savings opportunities can be identified. The intention of this article is to study and evaluate energy usage pattern of the Central Queensland University campus’ buildings, Queensland, Australia. This article presents the field survey results from the audit of an office building and performance-related measurements of the indoor environmental parameters, for instance, indoor air temperature, humidity and energy consumption concerned to the indoor heating and cooling load. Monthly observed energy usage information was employed to investigate influence of the climate conditions on energy usage.
Эти руководящие принципы описывают общие подходы к проектированию, строительству и модернизации школы пространства. В этом документе объясняется потенциал инновационных технологий, способствующих долгосрочному развитию и образованию детей. Руководящие принципы были разработаны в сотрудничестве с экспертами Всемирного банка, специализирующихся в различных областях.
This document presents the results of a case study on residential energy consumption and awareness of energy management systems in Kajang and Putrajaya, Malaysia. Questionnaires were distributed to 384 residents to collect data on appliance usage and opinions. Actual energy consumption was also measured using a power quality analyzer. The study found that average daily energy use was 25.8 kWh on weekends and 21.9 kWh on weekdays, with air conditioners accounting for 11.5 kWh daily. Most respondents (89.1%) reported awareness of energy usage and willingness to use home automation to reduce bills.
The document presents a comparative study of time series forecasting methods for short term electric energy consumption prediction in smart buildings. It analyzes energy consumption data collected from 13 buildings at a university campus over 5.5 years. Various statistical and machine learning methods are evaluated for their ability to predict daily energy consumption 1 day ahead, including ARIMA, neural networks, and ensemble techniques. Results show that machine learning methods like bagging and boosting ensembles performed best, and using over 7 days of historical data improved predictions.
Renewable Energy Education and Awareness at the University Level in PakistanUmair Shahzad
The rapid increase in the enrolment of students at higher education level in Pakistan in recent years is
expected to grow further. It is very essential for universities to update the educational curriculum according to latest
technological needs .Energy is a significant issue of Pakistan. The country has been facing severe crisis of energy since last
two decades. Availability of educated and trained personnel is important for successfully implementing any plans for
alternative energy sources. Owing to rising concerns about fossil fuel depletion and global climate change, there is an
imperative need for renewable energy experts and specialists, who are able to design, install and maintain these systems.
Most of the engineers are not even aware of the working technology of renewable energy systems, therefore, it is essential to
devise and introduce new courses and curriculum which prepare engineers of the future to work with renewables to utilize
alternative energy systems and contribute their part in putting an end to energy crisis. Gone are the days when miniscule
knowledge of renewable energy was sufficient for students. In today’s era, it is crucial to include courses which cover the
domains of technology, resources, design, implementation, economics, policies and applications of renewable energy
systems. At present, there is no strong foundation at various universities to provide education and awareness regarding
renewable energy and its long term benefits. The role of internet is very vital regarding renewable energy education and
awareness. This paper presents the importance of imparting renewable energy education to students at university level in
Pakistan.
The document discusses methods for short-term forecasting of electric energy consumption in smart buildings. It compares statistical and machine learning approaches using data from 13 buildings on a university campus in Spain. The best performing methods were ensemble machine learning approaches like bagging and boosting, which were able to more accurately predict energy consumption over the next day compared to statistical models. The study also found that using over 7 days of historical data led to better predictions.
An appraisal of the new nigerian senior secondary school physics curriculumAlexander Decker
The document summarizes and compares the old and new senior secondary school physics curriculums in Nigeria. The new curriculum will be implemented in 2011 and has six themes instead of five. An additional theme on physics in technology has been added. The new curriculum is more student-activity oriented with an emphasis on experimentation, questioning, discussion and problem solving. It also recommends an assessment protocol that evaluates students across three domains of learning. While the objectives remain similar between the old and new curriculums, the changes aim to better align the physics curriculum with national and global issues.
A Case Study Of An Educational Building Transformation To Renewable EnergyJoe Osborn
This document summarizes a case study analyzing the feasibility of transitioning the energy usage of Kabul University's Engineering School from conventional sources to renewable energy. It finds that installing a solar photovoltaic system with a total initial cost of 14,237,771 AFN and annual operation and maintenance costs of 341,862 AFN would pay for itself in under 4.5 years. Based on energy demand calculations and the renewable energy potential of solar power in Kabul, the study concludes such a transition would be both economically and technically viable.
The document discusses the development of an optimal green room management system to conserve energy by taking advantage of the thermal inertia effect where a room's temperature does not immediately rise or fall after heating/cooling is turned off. It proposes collecting indoor/outdoor temperature and electricity usage data using a wireless sensor network to build energy-temperature correlation models for each room and develop room scheduling algorithms to maximize energy savings. Experimental validation of the system using an actual sensor network deployment showed potential for 30% energy savings compared to existing room scheduling practices.
Investigating the applicability of pm ve ppde model in non air-conditioned ho...Alexander Decker
This document investigates the applicability of the PMVe-PPDe thermal comfort model in a non-air conditioned hostel building in Ile-Ife, Nigeria. Physical measurements of indoor environmental variables like air temperature, relative humidity and air velocity were taken in the hostel and used to calculate PMVe and PPDe values. Most of the calculated PMVe values fell within the comfort range recommended by standards. The obtained PPDe results showed slight overestimation of dissatisfaction under neutral conditions. The study concluded that the PMVe-PPDe model is applicable in the non-air conditioned hostel building in this climate when the proper expectancy factor is used.
Sustainable Energy Resource Buildings: Some Relevant Feautures for Built Envi...IJERA Editor
Energy has become a critical issue in national and global economic development. Its crucial importance to the nation’s building makes the development of energy resources one of the leading agenda of the present democratic government of Nigeria, towards lifting the nation to the comity of twenty (20) nations with the fastest growing economy in 2020. In achieving this, the building industry and in particular the architectural profession has a leading role to play in adopting education, designs, materials, and technology capable of reducing energy consumption in building within tropic region. This paper, therefore, appraises the important features of energy performance building through the use of sustainable innovative materials and technology that respond to climate condition while being environmentally friendly.
This document discusses the development of a hybrid building model that uses both physical and empirical methods to model energy and moisture transfer. The model divides the building into four subsystems: 1) conditioned indoor air space, 2) opaque exterior surfaces, 3) transparent fenestration surfaces, and 4) slab floors. Conservation laws are applied to each subsystem to model heat and mass transfer. The model uses an empirical residential load factor method to relate indoor and outdoor temperatures and calculate cooling/heating loads for each room. Simulations using the model under various ventilation scenarios can help reduce energy usage for cooling while maintaining thermal comfort.
Cascaded Thermodynamic and Environmental Analyses of Energy Generation Modali...Ozyegin University
This document summarizes a study that analyzes the energy and exergy flows of a high-performance academic building under five different operation scenarios, based on real measurements. The scenarios include: 1) the original design, 2) adding a ground-air heat exchanger, 3) installing roof-top solar PV panels, 4) using a trigeneration system instead of boilers, and 5) integrating all three alternative energy sources. Dynamic thermodynamic, economic and environmental analyses were performed for each scenario. It was determined that using a trigeneration system provided the best outcomes in terms of reduced energy demand and costs as well as improved exergy efficiency and sustainability, compared to the other scenarios. However, an integrated approach combining all
ISCN 2016: Working Group 2: Campus-wide Planning and Target SettingISCN_Secretariat
This document outlines campus sustainability efforts in Japan and showcases good practices at several universities. It discusses the establishment of CAS-Net JAPAN, a campus sustainability network, to promote cross-institution collaboration. Key themes for CAS-Net JAPAN include establishing sustainability organizations, action plans, and evaluation systems. The document also summarizes projects at Kyoto University using an environmental tax system, student involvement in environmental management at Chiba University, and Hokkaido University's sustainability assessment system. Finally, it outlines Fukushima College's regional rehabilitation training program in renewable energy, nuclear safety, and disaster mitigation following the Fukushima nuclear accident.
IRJET- Analysis of the Heat Transfer During Energy Storage in a Triplex Conce...IRJET Journal
This document analyzes heat transfer during energy storage in a triplex concentric tube using a phase change material (PCM). It discusses modeling the triplex concentric tube in Creo 2.0 and simulating heat transfer using computational fluid dynamics (CFD) in ANSYS. The study examines the impact of water temperature and heat transfer fluid flow on thermal energy storage. It analyzes heat transfer coefficient, heat transfer rate, and skin friction coefficient under different conditions. The main objective is to evaluate heat transfer during the charging and discharging processes of the PCM thermal energy storage unit.
Solar Heat Storage Technologies: Advancements and Integration in Renewable En...IRJET Journal
The document discusses solar heat storage technologies and their integration into renewable energy systems. It provides background on solar heat storage and its importance for generating energy without fossil fuels. Sensible heat storage stores thermal energy by increasing the temperature of a storage medium without phase transformation. Various solar heat storage technologies are described, including flat plate collectors, evacuated tube collectors, and concentrating solar power systems. The future of solar heat storage technologies is promising as materials improve and integration with other renewables increases. Challenges include the initial cost and weather dependence of solar energy systems. The document also examines thermal energy storage methods, classifications of solar energy storage, advantages and disadvantages, and the cost-effectiveness of solar heat storage technologies.
Beyond the Basics of A/B Tests: Highly Innovative Experimentation Tactics You...Aggregage
This webinar will explore cutting-edge, less familiar but powerful experimentation methodologies which address well-known limitations of standard A/B Testing. Designed for data and product leaders, this session aims to inspire the embrace of innovative approaches and provide insights into the frontiers of experimentation!
End-to-end pipeline agility - Berlin Buzzwords 2024Lars Albertsson
We describe how we achieve high change agility in data engineering by eliminating the fear of breaking downstream data pipelines through end-to-end pipeline testing, and by using schema metaprogramming to safely eliminate boilerplate involved in changes that affect whole pipelines.
A quick poll on agility in changing pipelines from end to end indicated a huge span in capabilities. For the question "How long time does it take for all downstream pipelines to be adapted to an upstream change," the median response was 6 months, but some respondents could do it in less than a day. When quantitative data engineering differences between the best and worst are measured, the span is often 100x-1000x, sometimes even more.
A long time ago, we suffered at Spotify from fear of changing pipelines due to not knowing what the impact might be downstream. We made plans for a technical solution to test pipelines end-to-end to mitigate that fear, but the effort failed for cultural reasons. We eventually solved this challenge, but in a different context. In this presentation we will describe how we test full pipelines effectively by manipulating workflow orchestration, which enables us to make changes in pipelines without fear of breaking downstream.
Making schema changes that affect many jobs also involves a lot of toil and boilerplate. Using schema-on-read mitigates some of it, but has drawbacks since it makes it more difficult to detect errors early. We will describe how we have rejected this tradeoff by applying schema metaprogramming, eliminating boilerplate but keeping the protection of static typing, thereby further improving agility to quickly modify data pipelines without fear.
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This document summarizes a scholarly review on the influence of unforeseen sub-factors on adaptive thermal comfort in classrooms of primary and secondary schools. It finds that in addition to the four main factors of thermal comfort prescribed by standards (air temperature, radiant temperature, metabolic rate, clothing insulation), other sub-factors like age, gender, season, local climate, socioeconomic status, adaptive behaviors, passive cooling/heating, building features and orientation also influence thermal comfort. Through an analysis of 54 studies from the last 15 years, it was found that seasonal changes, adaptive behaviors like clothing and window/fan use, and socioeconomic factors impact children's thermal comfort more than adults. A holistic approach is needed to fully understand
Energy Audit and Analysis of an Institutional Building under Subtropical Clim...IJECEIAES
Evaluation and estimation of energy consumption are essential in order to classify the amount of energy used and the way it is utilized in building. Hence, the possibility of any energy savings potential and energy savings opportunities can be identified. The intention of this article is to study and evaluate energy usage pattern of the Central Queensland University campus’ buildings, Queensland, Australia. This article presents the field survey results from the audit of an office building and performance-related measurements of the indoor environmental parameters, for instance, indoor air temperature, humidity and energy consumption concerned to the indoor heating and cooling load. Monthly observed energy usage information was employed to investigate influence of the climate conditions on energy usage.
Эти руководящие принципы описывают общие подходы к проектированию, строительству и модернизации школы пространства. В этом документе объясняется потенциал инновационных технологий, способствующих долгосрочному развитию и образованию детей. Руководящие принципы были разработаны в сотрудничестве с экспертами Всемирного банка, специализирующихся в различных областях.
This document presents the results of a case study on residential energy consumption and awareness of energy management systems in Kajang and Putrajaya, Malaysia. Questionnaires were distributed to 384 residents to collect data on appliance usage and opinions. Actual energy consumption was also measured using a power quality analyzer. The study found that average daily energy use was 25.8 kWh on weekends and 21.9 kWh on weekdays, with air conditioners accounting for 11.5 kWh daily. Most respondents (89.1%) reported awareness of energy usage and willingness to use home automation to reduce bills.
The document presents a comparative study of time series forecasting methods for short term electric energy consumption prediction in smart buildings. It analyzes energy consumption data collected from 13 buildings at a university campus over 5.5 years. Various statistical and machine learning methods are evaluated for their ability to predict daily energy consumption 1 day ahead, including ARIMA, neural networks, and ensemble techniques. Results show that machine learning methods like bagging and boosting ensembles performed best, and using over 7 days of historical data improved predictions.
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The rapid increase in the enrolment of students at higher education level in Pakistan in recent years is
expected to grow further. It is very essential for universities to update the educational curriculum according to latest
technological needs .Energy is a significant issue of Pakistan. The country has been facing severe crisis of energy since last
two decades. Availability of educated and trained personnel is important for successfully implementing any plans for
alternative energy sources. Owing to rising concerns about fossil fuel depletion and global climate change, there is an
imperative need for renewable energy experts and specialists, who are able to design, install and maintain these systems.
Most of the engineers are not even aware of the working technology of renewable energy systems, therefore, it is essential to
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2. and associated comfort in educational buildings is needed.
Previous studies have been performed in educational in-
stitutions at various levels, such as kindergarten [8e10], primary
school [11,12], high school [13,14], and university [15,16]. However,
each of these previous studies was unique, both in their research
method and sample characteristics. For example, in some of the
studies, ventilation modes were not defined. Meanwhile, most of
the adaptive thermal comfort studies were focused on naturally
ventilated buildings, but in reality, not many university buildings
rely on natural ventilation only. Thermal comfort analysis can be
used to identify the thermal perceptions of building occupants and
to identify possible energy savings. Using this approach in devel-
oping countries, it is necessary to understand occupants' adaptive
behaviour and thermal preferences vis-
a-vis those in developed
countries, which exhibit more environmentally friendly energy
consumption under similar climatic conditions. Malaysia shares
climatic conditions with parts of Japan [17]; however, residents
exhibit different adaptive behaviours to maintain thermal comfort
[18]. In this study, we investigated this behaviour and considered
whether or not lower energy consumption is related to factors
affecting thermal comfort. In particular, we focused on the class-
room environment, where students at all levels of education spend
most of their time [19]. The main objectives of this study were: (1)
to investigate students' comfort temperature ranges in university
classrooms in Malaysia and Japan during the summer season; (2) to
compare comfort temperatures with related standards; and (3) to
observe students' adaptive behaviour in maintaining their thermal
comfort.
2. Methodology
2.1. Climatic conditions
In Malaysia, study locations were chosen in Shah Alam and
Kuala Lumpur, both within the Klang Valley, located on the south-
west of the Malaysian peninsula. In Japan, study locations were
selected in Fukuoka, the capital of Fukuoka Prefecture, which is
located on the northern coast of Kyushu Island. The Klang Valley
experiences a tropical rainforest climate (i.e. it is hot and humid
throughout the year) based on the K€
oppen world climate classifi-
cation of Kottek et al. [20]. Fukuoka's climate is categorized as
humid subtropical, with mild winters and hot humid summers.
Surveys were conducted during the 2014 boreal summer season,
when climatic conditions were most similar in both locations. The
mean annual temperature and humidity in Malaysia are 27.0 C and
80%, respectively. During the Fukuoka summer season, mean
temperature and humidity are 26.9 C and 70%, respectively.
2.2. Study buildings
Three universities participated in this study: Universiti Tekno-
logi MARA (UiTM) Shah Alam campus and Universiti Teknologi
Malaysia (UTM) Kuala Lumpur campus in Malaysia, and Kyushu
University (KU) Chikushi campus in Japan (Table 1; Fig. 1). The
UiTM and KU campuses are located in suburban areas, while UTM is
in an urban area.
Classrooms used in this study were occupied by lecturers and
students and were picked randomly after securing the permission
of the Dean of each university faculty. In total, six classrooms in the
building of the Malaysia Japan International Institute of Technology
(MJIIT) of UTM, and 14 classrooms in the building of the Faculty of
Mechanical Engineering at UiTM were used. In Japan, four class-
rooms were selected in the Interdisciplinary Graduate School of
Engineering Science (IGSES) buildings of KU. For reference pur-
poses, the orientation of windows in each classroom that was
investigated was also recorded.
The MJIIT building in UTM is a ten-level building with two wings
to the west and east (Fig. 1a). The total area of the building is
24,200 m2
. All of the classrooms used were located in the west
wing, spread over levels two, four, seven, and eight. The area of
each classroom was approximately 57 m2
with a seating capacity
for 40 students (Fig. 2a).
The Engineering Tower building in UiTM (Fig.1b) consisted of 20
levels with a total area of 31,439 m2
. Levels nine, ten, and eleven
were chosen for use in this study. Classroom area ranged between
38 and 47 m2
and rooms were occupied by up to 30 students
(Fig. 2b). All classrooms had a similar design, including tinted
windows, fans, and an air conditioning system for cooling pur-
poses; however, some classrooms had north-west facing windows
while others had south-east facing windows.
In Kyushu University, classrooms were located in two buildings
of the Interdisciplinary Graduate School of Engineering Science
(IGSES), and were distributed on levels one and three (Fig. 1c). Each
classroom had an approximate area of 55 m2
and a seating capacity
Table 1
Summary of classrooms and sample size.
Country University, Campus Location Measurement period Building block Mode Classroom code Orientation n Total
Malaysia UTM, Kuala Lumpur 3
080
N, 101
420
E 13/4/2013e5/5/2013
(20 days)
MJIIT CL CR1 W 63 677
CR2 Isolated room 207
CR3 W 85
CR4 S 68
CR5 W 83
CR6 W 171
UiTM, Shah Alam 3
040
N, 101
300
E 5/3/2013e21/5/2013
(29 days)
Faculty
Mechanical
Engineering
FR CR2, CR3, CR4, CR5, CR6 W 106 302
W
W
CL CR1, CR7, CR8, CR9 W 196
W
Japan KU, Chikushi 6
530
S, 107
360
E 24/2/2013e12/3/2013
(13 days)
A FR CA1, CA2 E 86 449
CL CA1, CA2, CA3 E 260
E
B FR CA4 N 66
CL CA4 N 37
Total 1428
UTM: Universiti Teknologi Malaysia; UiTM: Universiti Teknologi MARA; KU: Kyushu University.
CL: Cooling; FR: free-running; n: number of votes.
E: East; N: North; W: West.
S.A. Zaki et al. / Building and Environment 122 (2017) 294e306 295
3. of up to 40 students (Fig. 2c). The two buildings contained a split
type air conditioning system. Despite the availability of air condi-
tioning, these classrooms were operated on a changeover mixed-
mode basis, and for the purpose of this study, they were classi-
fied as FR when air conditioning was not in use and CL otherwise.
Ergo, both CL and FR results in Japan come from the same set of
respondents. Some classrooms faced towards the east and were
exposed to morning sunlight, while others faced west and were
exposed to afternoon sunlight.
2.3. Data collection
Data were obtained through indoor field measurements and
questionnaire survey, which were performed simultaneously. For
each classroom, data collection was carried out at times where
students were participating in a learning activity (both morning
and afternoon). All materials, including the questionnaire, were
placed in the classroom 20 min before the lecture started. Before
data collection, students were briefed about their participation in
the survey.
2.3.1. Thermal environment assessment
Field measurements included five objective parameters: out-
door temperature (To), indoor air temperature (Ta), indoor globe
temperature (Tg), indoor air velocity (Va), and indoor relative hu-
midity (RH). For outdoor environmental parameters, data were
obtained from the MJIIT weather station and the Japan Meteorology
Agency [21]. For indoor climatic parameters (Table 2), calculation of
mean radiant temperature followed the procedures laid out in the
American Society of Heating, Refrigerating and Air-Conditioning
Engineers (ASHRAE) Handbook [22], while indoor operative tem-
perature was calculated as the mean of mean radiant temperature
(Tmrt) and Ta [23].
To investigate indoor conditions, instruments were placed at
four to five points around each classroom (Fig. 3). Each pair of
thermo recorders (TR-77Ui and TR-52i) was attached to a stand that
positioned them 1.1 m above the ground (Fig. 4). The remaining
instruments were placed in the corners of the room and measured
Ta and Tg. For each set of measurements, instruments were left for
90 min with data collected at 10 s intervals.
2.3.2. Thermal comfort survey
Questionnaires were prepared in English and accompanied by
local language translations. They were compiled based on the
works of Damiati et al. [18], Indraganti et al. [24] and Mustapa et al.
[16]. Thermal sensation was evaluated using the ASHRAE 7-point
sensation scale, 5-point scale of thermal preference, thermal
acceptability, and 6-point scale of overall comfort (Table 3).
Collected meta-data included gender, age, height and weight,
adaptive behaviour, and clothes worn by the student. Question-
naires were distributed before the class started and students were
asked to answer questions at the end of the class. Because all re-
spondents were performing the same activity, listening to lectures,
the metabolic rate is assumed to be equal to 1.2 met, based on
ASHRAE Standard 55 [25].
In total, 1428 questionnaires were completed; however, 13 were
removed owing to measurement error because the sensors were
not attached properly to the instruments (i.e. 1415 responses were
used for analysis). Respondents were all university students aged
between 20 and 23 years old (Table 4). Other physical parameters
were similar across all locations (i.e. weight, height, BMI), with fe-
male respondents generally having smaller bodies than male re-
spondents. The ratio of female to male respondents was
approximately even in Malaysia, while there were more male re-
spondents in Japan (93.5%). The mean clothing insulation of
Fig.
1.
Facade
of
investigated
buildings
in:
(a)
Universiti
Teknologi
Malaysia
(UTM),
(b)
Universiti
Teknologi
MARA
(UiTM),
and
(c)
Kyushu
University
(KU).
S.A. Zaki et al. / Building and Environment 122 (2017) 294e306
296
4. students in Japan, both female and male, is lower than that in
Malaysia. In terms of gender differences, female students in KU and
UiTM have slightly lower clothing insulation compared to male
students, and vice versa in UTM.
Fig. 2. Classroom conditions during learning activities in: (a) Universiti Teknologi Malaysia (UTM), (b) Universiti Teknologi MARA (UiTM), and (c) Kyushu University (KU).
Table 2
Specification of measurement instruments.
Instrument Parameter Manufacturer, Country Sensor type Resolution Accuracy and tolerance
Thermo recorder TR-77Ui Air temperature
Relative humidity
TD, USA External sensor 0.1
C
1% RH
±0.5
C
±5% RH [at 25
C, 50%]
Thermo recorder TR-52i Globe temperature TD, USA External sensor 0.1
C ±0.3
C [20
Ce80
C]
Hot-wire anemometer Air movement Kanomax, Japan Needle probe 6542-2G 0.01 m/s ±(2% of reading ± 0.0125) m/s [0.10e30.0 m/s]
VelociCalc 9565 Air movement TSI, USA Straight probe 960 0.01 m/s ±3% of reading
Fig. 3. Instrument layout in the classrooms of: (a) Universiti Teknologi Malaysia (UTM), (b) Universiti Teknologi MARA (UiTM), and (c) Kyushu University (KU). Cross-filled circles
denote 52i thermo recorders, triangle-filled circles denote VelociCal 9565 air movement recorders, and star-filled circles denote 77Ui thermo recorders. The positions of air
conditioners (AC; dark grey shading), fans (light grey shading), desks (blue cross-hatched areas), windows, doors, students, and lecturers are labelled. (For interpretation of the
references to colour in this figure legend, the reader is referred to the web version of this article.)
S.A. Zaki et al. / Building and Environment 122 (2017) 294e306 297
5. 3. Results and discussion
3.1. Outdoor and indoor thermal environment during the voting
The results showed that the mean outdoor temperature at the
time of measurement was much lower in Japan than in Malaysia;
however, the mean indoor air temperatures were similar, regard-
less of ventilation mode (Table 5). The results suggest that indoor
relative humidity (RH) is impacted by ventilation mode. Locations
under FR mode had higher RH than those under CL mode. The
lowest indoor relative humidity was found at UTM (Malaysia),
which was operating under CL mode, while the highest value was
observed at KU (Japan), which was operating under FR mode. In
contrast, indoor air velocity was not impacted by ventilation. In
both FR and CL mode, classrooms in Japan had the lowest air ve-
locity (0.10 m/s).
Mean values of the four thermal indices (Ta, Tg, Tmrt, and Top)
were similar for each location (i.e. 1 C difference) and all had
significant linear regressions (p 0.001) and strong correlations
(Table 6). These result confirm that any one of these indices is
suitable for analysis, and we chose to focus on operative
temperature since it is used to determine comfort ranges in inter-
national standards (i.e. ASHRAE [25] and CEN [26]).
3.2. Subjective evaluations
Questionnaire responses showed that the mean thermal
sensation vote (TSV) was within 1 TSV 1 at all locations, with
the highest value and the value closest to 0 both observed in KU
under FR mode (Table 7). The mean values at all other locations
were 0, indicating that most occupants felt cold inside the
buildings. For the 7-point TSV scale, regardless of mode (FR or CL) or
location, the highest proportion of respondents were ‘neutral,
except under CL mode in Japan (KU), where the highest proportion
(39.4%) voted for ‘slightly cool’ (Fig. 5). Most respondents preferred
‘no change’ to the indoor temperature, consistent with mean
thermal preferences (TP) that were mostly close to
0 (0.1 TP 0.1), with the exception of Japan under FR mode,
where most occupants tended to prefer warmer conditions. The
mean overall comfort (OC) ranged between 2.5 and 3.0, indicating
‘slightly comfortable’ and ‘comfortable’, respectively. The predicted
values, predicted mean vote (PMV) and predicted percentage of
dissatisfied (PPD) results are slightly different from the question-
naire results. While the mean TSV in all locations, except FR mode
in Japan, was less than zero, only students in CL mode classrooms in
Malaysia were predicted to have negative mean PMV: 0.4
and 0.3 in UTM and UiTM, respectively. This indicates that the
neutral sensations for occupants in these locations are biased to-
wards the ‘slightly cool’ side. The deviation from neutral thermal
sensation is evidenced by high PPD values compared to other lo-
cations: 14.8% and 16.1% in UTM and UiTM, respectively. The PMV
and PPD in FR mode in Malaysia, as well as both ventilation modes
in Japan, are closer to the neutral thermal sensation.
3.3. Thermal comfort zone
For indoor temperature change, Probit analysis was performed
to predict the proportion of votes for each category of the 7-point
scale [27e29]. Furthermore, this approach was used to calculate
the temperature with highest proportion of votes within TSV ±1,
Fig. 4. Thermo recorders and sensors attached to a stand and held 1.1 m above the
floor.
Table 3
Thermal comfort scales.
Thermal sensation Thermal preference Thermal acceptability Overall comfort
No. Scale No. Scale No. Scale No. Scale
3 Cold 2 Much warmer 1 Acceptable 1 Very comfortable
2 Cool 1 Slightly warmer 0 Not acceptable 2 Comfortable
1 Slightly cool 0 No change 3 Slightly comfortable
0 Neutral 1 Slightly cooler 4 Slightly uncomfortable
1 Slightly warm 2 Much cooler 5 Uncomfortable
2 Warm 6 Very uncomfortable
3 Hot
Thermal sensation 7-point scale of the American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE).
Table 4
Mean demographics and clothing insulation of questionnaire respondents.
University Gender Age (year) Weight (kg) Height (m) BMI (kg/m2
) Clothing insulation (clo)
UTM Female (n ¼ 111) 20 (1) 49.8 (8.9) 1.57 (0.06) 19.8 (4.2) 0.56 (0.16)
Male (n ¼ 148) 20 (1) 64.7 (16.3) 1.70 (0.08) 22.4 (4.8) 0.51 (0.18)
UiTM Female (n ¼ 135) 21 (1) 54.5 (10.9) 1.59 (0.06) 21.6 (4.2) 0.59 (0.17)
Male (n ¼ 167) 21 (1) 67.4 (17.6) 1.69 (0.07) 23.5 (5.5) 0.62 (0.20)
KU Female (n ¼ 29) 23 (1) 47.4 (4.6) 1.58 (0.05) 19.0 (1.2) 0.46 (0.12)
Male (n ¼ 420) 23 (1) 65.5 (10.6) 1.72 (0.06) 22.0 (3.3) 0.45 (0.12)
Values in brackets denote one standard deviation around the mean.
UTM: Universiti Teknologi Malaysia; UiTM: Universiti Teknologi MARA; KU: Kyushu University.
n: number of votes.
S.A. Zaki et al. / Building and Environment 122 (2017) 294e306
298
6. which was assumed to be the optimum condition for comfort.
Based on TSV, analysis was conducted using indoor operative
temperature (Top) as the covariate. The results for CL mode data
from both countries were significant to the p 0.001 level;
however, in FR mode the equations were not statistically significant
(Table 8). Mean temperatures for each equation were estimated by
dividing the constant for each TSV category with the Probit
regression coefficient [29]. Meanwhile, the standard deviation of
cumulative normal distribution was the inverse of the Probit
regression coefficient.
All equations were plotted into sigmoid curves using the func-
tion [18,29,30].
Probability ¼ CDF.NORMAL (quant, mean, S.D.) (1)
where CDF.NORMAL is the cumulative distribution function for
normal distribution and ‘quant’ is the operative temperature (C).
The results indicated that the proportion of people feeling cold
fell as temperature increased, while the proportion of those feeling
warm increased (Fig. 6a and b). By extracting the three central
points of the 7-point ASHRAE scale, the proportion of people
feeling comfortable was projected (Fig. 6c) and the function for the
curve was calculated by subtracting the Probit equations for TSV ±1
(i.e. the comfortable categories of the 7-point scale). In both
countries, the indoor operative temperature with the highest per-
centage of people feeling comfortable was ~26.0 C; although, the
Table 5
Mean values of climatic parameters.
University Mode To
(
C)
Ta
(
C)
Tg
(
C)
Tmrt
(
C)
Top
(
C)
RH
(%)
Va
(m/s)
UTM CL (n ¼ 677) 30.8 (2.4) 24.2 (0.8) 24.2 (0.9) 24.2 (1.1) 24.2 (0.9) 49.5 (6.8) 0.13 (0.11)
UiTM FR (n ¼ 106) 29.9 (3.1) 24.9 (0.3) 25.0 (0.5) 25.1 (0.9) 25.0 (0.5) 66.1 (3.0) 0.19 (0.05)
CL (n ¼ 196) 33.4 (2.9) 24.0 (1.0) 24.1 (1.0) 24.3 (0.8) 24.1 (0.9) 59.7 (6.5) 0.28 (0.09)
KU FR (n ¼ 152) 25.3 (1.6) 25.2 (0.7) 25.3 (0.7) 25.4 (0.7) 25.3 (0.7) 69.8 (5.0) 0.03 (0.02)
CL (n ¼ 284) 25.5 (2.5) 25.1 (0.8) 25.1 (0.8) 25.1 (0.8) 25.1 (0.8) 63.4 (6.7) 0.03 (0.02)
Values in brackets denote one standard deviation around the mean; To: outdoor air temperature Ta: indoor air temperature; Tg: globe temperature; Tmrt: mean radiant
temperature; Top: operative temperature; RH: indoor relative humidity; Va: air movement.
UTM: Universiti Teknologi Malaysia; UiTM: Universiti Teknologi MARA; KU: Kyushu University.
n: number of votes; CL: cooling; FR: free-running.
Table 6
Regression equations and correlation coefficients of thermal indices.
Mode Ta:Tg Ta:Tmrt Ta:Top
FR (n ¼ 258) Tg ¼ 0.97 Ta þ 0.96 (0.87) Tmrt ¼ 0.97 Ta þ 1.06 (0.65) Top ¼ 0.98 Ta þ 0.55 (0.88)
CL (n ¼ 1157) Tg ¼ 0.99 Ta þ 0.22 (0.98) Tmrt ¼ 0.99 Ta þ 0.27 (0.91) Top ¼ 0.99 Ta þ 0.26 (0.98)
Values in brackets denote correlation coefficients (r); Ta: indoor air temperature; Tg: globe temperature; Tmrt: mean radiant temperature; Top: operative temperature.
n: number of votes.
Table 7
Mean values of subjective parameters.
University Mode TSV TP PMV PPD (%) OC
UTM CL
(n ¼ 677)
0.7
(1.3)
0.0
(0.9)
0.4
(0.6)
14.8
(13.6)
3.0
(1.1)
UiTM FR
(n ¼ 106)
0.9
(0.9)
0.1
(0.8)
0.1
(0.4)
8.7
(4.3)
2.5
(0.9)
CL
(n ¼ 196)
0.9
(1.0)
0.1
(0.9)
0.3
(0.7)
16.1
(15.8)
2.7
(0.8)
KU FR
(n ¼ 152)
0.1
(1.3)
0.3
(0.7)
0.2
(0.3)
8.0
(3.9)
2.9
(1.1)
CL
(n ¼ 284)
0.6
(1.1)
0.1
(0.7)
0.1
(0.3)
7.6
(4.6)
2.8
(1.0)
Values in brackets denote one standard deviation around the mean; TSV: mean
thermal sensation vote; TP: mean thermal preferences; OC: mean overall comfort,
PMV: predicted mean vote.
UTM: Universiti Teknologi Malaysia; UiTM: Universiti Teknologi MARA; KU: Kyushu
University.
n: number of votes; CL: cooling; FR: free-running.
Fig. 5. Proportion of respondents selecting each value of thermal sensation vote (TSV) under free-running (FR; grey colour) and cooling (CL; white colour) conditions in: a) Malaysia
and b) Japan.
S.A. Zaki et al. / Building and Environment 122 (2017) 294e306 299
7. proportion was slightly higher in Japan (86%) compared with
Malaysia (80%). In both countries, approximately 70% of re-
spondents were comfortable when the temperature was between
24 and 28 C.
3.4. Comfort temperature
3.4.1. Regression analysis
Since the 1930s, regression analysis has been used to investigate
thermal comfort datasets [31]. Comfort temperature is traditionally
Table 8
Probit equations for thermal sensation vote.
Country Mode Equation Median (
C) S.D. N R2
S.E.
Malaysia CL P(3) ¼ 0.304 Top 5.85 19.3 3.293 872 0.07 0.039
P(2) ¼ 0.304 Top 6.63 21.8
P(1) ¼ 0.304 Top 7.50 24.7
P(0) ¼ 0.304 Top 8.62 28.4
P(1) ¼ 0.304 Top 9.16 30.2
P(2) ¼ 0.304 Top 9.55 31.4
Japan CL P(3) ¼ 0.444 Top 9.34 21.0 2.251 284 0.09 0.085
P(2) ¼ 0.444 Top 10.02 22.6
P(1) ¼ 0.444 Top 11.24 25.3
P(0) ¼ 0.444 Top 12.43 28.0
P(1) ¼ 0.444 Top 12.97 29.2
P(2) ¼ 0.444 Top 13.35 30.0
S.D.: standard deviation; N: number of votes; R2
: coefficient of determination; S.E.: standard error.
CL: cooling.
Top: operative temperature (
C); P(3) is the Probit of the proportion of the votes that are 3 and less; P(2) is the Probit of the proportion that are 2 and less, and so forth.
Fig. 6. Proportion of votes in each category of the American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) 7-point scale under cooling (CL) mode in (a)
Malaysia and (b) Japan as a function of indoor operative temperature (Top). (c) Proportion of respondents considered ‘comfortable’ in Japan (circles) and Malaysia (crosses) as a
function of Top.
S.A. Zaki et al. / Building and Environment 122 (2017) 294e306
300
8. obtained by regressing the subjective TSV and indoor temperature.
In this study, linear regression was conducted using indoor oper-
ative temperature as the independent variable and the 7-point TSV
ASHRAE scale as the dependent variable (Fig. 7). Predicted mean
vote (PMV) was calculated for each set of data based on six pa-
rameters: Ta, Tmrt, Va, RH, metabolic rate, and clothing insulation,
using the PMV calculator plugin for excel by Tanabe and Sato [32].
Under CL mode, regression equations for both countries were
found to be significant at the p 0.001 level, despite low R2
values;
however, regression equations were not statistically significant
under FR mode, for which too few samples were available (Table 9).
The slope of the regression line was 0.332 units/C in Malaysia and
0.424 units/C in Japan, with the change in temperature per point of
TSV found to be 3.0 C and 2.3 C, respectively. The neutral tem-
peratures acquired were 26.5 C and 26.3 C for Malaysia and Japan,
respectively.
3.4.2. Griffiths' method
As regression analysis was only possible for data collected under
CL mode, the Griffiths' method [33] was also used to estimate the
comfort temperatures in all locations. This approach was suitable
for use with both CL and FR because it can be used to calculate
neutral temperatures from small numbers of samples using a pre-
sumed constant as the rate of temperature change per point of
sensation scale. Comfort temperatures using the Griffiths' method
were calculated using the expression:
Tc ¼ T þ (0 TSV)/a (2)
where Tcomf is the comfort temperature (C), T is temperature (C),
and a indicates Griffiths' constant.
For a, we tested three different constant values (0.25, 0.33, and
0.50), as previously employed by Nicol et al. [34], Rijal et al. [35],
and Mustapa et al. [16], respectively. For most locations, the mean
comfort temperatures calculated using these values were higher
when a smaller constant was used (Table 10), with the exception of
data collected under FR mode in Japan. Given the similar climatic
conditions in Japan and Malaysia at the time of the study, the range
of measured indoor operative temperatures was relatively narrow.
Using 0.25 and 0.33 as a, comfort temperatures were least consis-
tent with the measured range. On this basis, we concluded that 0.50
was the most appropriate coefficient. This is in line with the study
of Nicol and Humphreys [36], who found that the actual value of the
constant must be 0.40.
The results also showed that mean temperatures based on the
three conditions were almost identical for each location (Table 11).
Furthermore, estimated comfort temperatures using a Griffiths'
constant of 0.50 resulted in values closest to neutral temperatures.
Using 0.50 as the Griffiths' constant, the mean comfort operative
temperature under FR mode in Japan (25.1 C) was lower than that
in Malaysia (26.8 C). In contrast, students under CL mode in Japan
had a mean higher comfort temperature (26.2 C) than those in
Malaysia (25.6 C). These results could mean that Japanese students
are more sensitive to thermal changes caused by different venti-
lation modes operated during the summer; however, the differ-
ences are very small (1 C) and may not be significant. This gap
could be affected by the insulation of clothing worn by students in
Japan, which was considerably lower than that of clothes worn by
students in Malaysia (see Table 7). Additionally, it might also be
caused by the fact that the Japanese sample was predominantly
male, compared to the Malaysian sample, in which the numbers of
students of each gender were almost equal. This supports findings
Fig. 7. Linear regression (solid black line) through thermal sensation vote (TSV) vs. indoor operative temperature (Top) under cooling (CL) mode in (a) Malaysia and (b) Japan. Dashed
black line denotes the predicted mean vote (PMV).
Table 9
Regression equations under cooling (CL) mode.
Country Mode Equation n R2
S.E. p
Malaysia CL TSV ¼ 0.332Top 8.8 872 0.06 0.044 0.001
Japan CL TSV ¼ 0.426Top 11.2 284 0.09 0.083 0.001
n: number of votes; R2
: coefficient of determination; S.D.: standard deviation; S.E.:
standard error, p: significance level.
TSV: thermal sensation vote; Top: indoor operative temperature.
Table 10
Comfort operative temperatures based on the Griffiths' method.
Country Mode n a ¼ 0.25 a ¼ 0.33 a ¼ 0.50
Malaysia FR 106 28.6 (3.7) 27.7 (2.8) 26.8 (1.9)
CL 872 27.0 (4.7) 26.4 (3.6) 25.6 (2.4)
Japan FR 152 24.9 (5.1) 25.0 (3.9) 25.1 (2.6)
CL 284 27.3 (4.3) 26.8 (3.2) 26.2 (2.1)
Values in brackets denote one standard deviation around the mean; a: Griffiths'
constant value employed.
FR: free-running, CL: cooling.
n: number of votes.
S.A. Zaki et al. / Building and Environment 122 (2017) 294e306 301
9. from previous studies [37e39], that gender differences could affect
thermal sensation.
While students in Malaysia showed predictable results: higher
comfort temperature in FR mode compared to CL mode, students in
Japan have reversed results. During summer season, Japanese
government recommends the temperature setting for cooling at
28 C [40]. Generally, buildings with FR mode have low tempera-
ture condition and people find that temperature is comfortable.
Meanwhile in CL mode, people set high temperature based on the
government's suggestion and people find that temperature is
comfortable. These results were concluded in several studies in
Japan, based on field survey during summer season in offices [16],
[30] [41], as well as houses [29], [42].
The results could also indicate that students in Malaysia are
acclimatized to their environment, allowing those under FR mode
to be comfortable at higher temperatures and vice versa. Compared
with the other three thermal indices (Tci, Tcg, and Tcmrt), mean
comfort operative temperature was similar for all locations (Fig. 8).
For all of these results, it is important to note that the students in
the KU classrooms with different ventilation modes were the same
group of people, since the buildings employed changeover mixed-
mode ventilation [43]. In contrast, classrooms in Malaysia were
designed to use either FR or CL mode, meaning that the re-
spondents for each ventilation mode were different groups of
people.
Previous studies of thermal comfort in classrooms have shown
Fig. 8. Comfort operative temperatures for different thermal indices based on a Griffiths' constant value (a) of 0.50 in (a) Malaysia under cooling (CL) and free-running (FR) mode,
and in (b) Japan under the CL and FR modes.
Table 12
Comfort temperatures from different studies.
Ref. Year Country Mode Sample size To (
C) Thermal index Tcomf (
C)
[45] 1998 Hawaii, USA FR 1052 24.0e33.0 Top 27.4
[14] 2003 Singapore FR 506 26.2e30.0 Top 28.8
[44] 2006 Taiwan FR 362 23.1e30.5a
Top 26.2
[15] 2014 India FR 121 14.5e33.0 Top 26.5
[16] 2016 Japan FR 81 3.5 28.0 3.6 Tg 26.7 (1.9)
Current study Malaysia FR 106 29.9 Top 26.8 (1.9)
Current study Japan FR 152 25.3 Top 25.1 (2.6)
[45] 1998 Hawaii, USA CL 703 24.0e33.0 Top 26.8
[44] 2006 Taiwan CL 932 23.1e30.5a
Top 25.6
[46] 2011 China CL 82 24.5e30.0 Top 26.8
[47] 2015 Indonesia CL 90 3.7 25.6e32.9 3.8 Ta 24.9
[18] 2016 Malaysia CL 1114 31.2 Top 25.6 (2.2)
[16] 2016 Japan CL 222 3.9 28.0 3.10 Tg 26.6 (1.6)
Current study Malaysia CL 872 31.4 Top 25.6 (2.4)
Current study Japan CL 297 25.4 Top 26.2 (2.1)
FR: free-running; CL: cooling.
To: outdoor air temperature.
Top: indoor operative temperature; Ta: indoor air temperature; Tg: indoor globe temperature.
Tcomf: comfort temperature; values in brackets denote one standard deviation around the mean.
a
Temperature obtained from http://www.weatherbase.com/.
Table 11
Mean temperatures for selected TSV, TP, and OC.
Country Mode TSV ¼ 0 TP ¼ 0 OC 3
Malaysia FR n ¼ 39 25.0 (0.4) n ¼ 67 25.0 (0.4) n ¼ 60 25.1 (0.5)
CL n ¼ 288 24.4 (0.9) n ¼ 454 24.3 (0.9) n ¼ 174 24.1 (0.9)
Japan FR n ¼ 61 25.4 (0.8) n ¼ 83 25.3 (0.7) n ¼ 59 25.3 (0.7)
CL n ¼ 101 25.3 (0.7) n ¼ 166 25.1 (0.7) n ¼ 117 25.1 (0.7)
TSV: thermal sensation vote, TP: thermal preference, OC: overall comfort; values in brackets denote one standard deviation around the mean; n: number of votes.
FR: free-running, CL: cooling.
S.A. Zaki et al. / Building and Environment 122 (2017) 294e306
302
10. various results. In both tropical climates and in temperate climates
during the summer season, most comfort temperatures have been
found to be high (Table 12). In the current study, the comfort
temperatures of students under FR mode in Malaysia were found to
be slightly higher than those in university classrooms in Taiwan
[44] and India [15]. In contrast, studies in primary schools in Hawaii
[45] and Singapore [14] have shown even higher results (although
the latter study combined the comfort temperatures of students
and teachers). Postgraduate students in Fukuoka [16] were also
found to have a higher comfort temperature compared with the
Japanese students in this study who were under FR mode.
The comfort temperature of students under CL mode in Malaysia
was identical with the results of previous studies of postgraduate
students in Malaysia [18], as well as of university classrooms in
Taiwan [44]. Other studies in tropical countries showed various
results, including lower comfort temperatures in university class-
rooms in Indonesia [47], and higher ones in primary school class-
rooms in Hawaii [45]. Similarly, the comfort temperature found in
this study for Japanese students under CL mode was similar to the
results from postgraduate students in Japan [16]. A study based in
China under a temperate climate during summer season resulted in
a slightly higher comfort temperature (26.8 C) [46].
3.5. Comparison with standards
The comfort temperatures in each location were also compared
to adaptive models from existing standards, including Comit
e
Europ
een de Normalisation (CEN) Standard EN15251 [26] and
ASHRAE Standard-55 [25] for FR mode, and the Chartered Institute
of Building Services Engineers (CIBSE) guide [48] for CL mode
(Fig. 9). All of these standards have thermal comfort models based
on outdoor temperatures. The CEN Standard EN15251 and the
CIBSE guide use running mean outdoor air temperature (Trm),
which is the weighted mean of outdoor air temperatures of seven
sequential days prior to the day of survey [26]. The ASHRAE
Standard-55 uses monthly mean outdoor air temperature (Tom),
which is calculated from mean daily outdoor air temperatures (Tod)
for all days in each month [25]. The ASHRAE standard (2004) [49] is
Fig. 9. Comparison of the results with existing standards: a) Comit
e Europ
een de Normalisation (CEN) Standard EN15251, b) American Society of Heating, Refrigerating and Air-
Conditioning Engineers (ASHRAE) Standard-55, and c) the Chartered Institute of Building Services Engineers (CIBSE) guide. Filled circles denote data from Malaysia, while open
circles denote data from Japan. Black dashed lines denote the upper and lower limits of the corresponding standard. Recommended temperature settings based on local regulations
in each country are illustrated using horizontal lines (continuous grey line for Japan and dash-dot grey line for Malaysia).
S.A. Zaki et al. / Building and Environment 122 (2017) 294e306 303
11. based on the monthly mean outdoor temperature. The modified
ASHRAE standard (2013) [25] indicated the prevailing mean out-
door temperature, which is based on mean daily outdoor air tem-
peratures. However, the regression coefficient and constant are the
same for the original and revised version of the standard [25,50,51].
The results from FR mode were consistent with both relevant
standards (Fig. 9a and b); however, more points fell within the
highest comfort zone category of the ASHRAE standard than in that
of the CEN standard. While most of the comfort temperature results
from Malaysia and Japan were within category I of the CEN adaptive
thermal comfort model, some points fell below the lower limit
(Fig. 9a). In contrast, all students' comfort temperatures under FR
mode in Malaysia were compatible with the ASHRAE standard's
90% acceptability level. Only one point from the FR mode in Japan
was situated between the upper limits of acceptability (80% and
90%; Fig. 9b). Most results from under CL mode in both countries
were situated within the CIBSE guide comfort zone (Fig. 9c). Since
the classrooms in Japan are situated in change-over mixed mode
building, the data from both FR and CL modes were also combined
and compared with both ASHRAE and CEN standards as shown in
Fig. 10 a and b.
3.6. Adaptive behaviour
Thermal comfort is greatly affected by adaptation. In this study,
students were asked to declare any adaptive action they had un-
dertaken to adjust to the indoor thermal condition in the class-
room. Under both FR and CL ventilation modes, most students in
Japan did nothing to adapt themselves because lectures lasted only
90 min. The most common adaptive activity in Japan was drinking
water or juice (15%), perhaps reflecting the easiest way for students
to respond to the existing thermal environment without inter-
rupting learning activities (Fig. 11). While there could be other
reasons for students to be consuming beverages, the questionnaire
specifically asked them to choose any activities they did in order to
overcome thermal discomfort. In Malaysia, the most common ac-
tion was changing the temperature setting of the AC (27%), which
was more popular than ‘did nothing’. This is in line with the results
of previous studies in Malaysia, Indonesia, and Japan, which found
that office building occupants in Malaysia tended to use AC systems
more than those in the other two countries [18]. Another study in
Chongqing [52] found that respondents under FR mode in class-
rooms tended toward other behavioural adaptations (e.g. adjusting
clothes, operating ceiling fans, and consuming beverages). These
results are also in agreement with a similar study conducted in
Fukuoka [16], where most students under CL mode declared that
they ‘did nothing’ to adapt, while students under FR mode tended
to overcome thermal discomfort by drinking water, switching on
fans, and/or opening windows and doors. Therefore, these results
show that in less energy intensive environments, such as FR mode
Fig. 10. Comparison of results from change-over mixed mode ventilation in Japan, with a) CEN standard, and b) ASHRAE standard.
Fig. 11. Adaptive actions taken by survey participants to alter their thermal environment in: a) Malaysia and b) Japan.
S.A. Zaki et al. / Building and Environment 122 (2017) 294e306
304
12. in Japan, more adaptive actions are taken by occupants to remain
thermally comfortable. Conversely, by encouraging active partici-
pation by occupants in maintaining their thermal comfort, it is
possible to encourage energy savings from reduced HVAC use.
4. Conclusions
In this study, thermal comfort in university classrooms in
Malaysia and Japan was investigated. Based on the results, a
number of conclusions were drawn. While 70% of respondents
voted within the three central TSV points, within the comfortable
range, those who admitted to feeling thermally uncomfortable
were usually cold, except in FR mode in Japan. This points to some
degree of overcooling in university classrooms in the locations
investigated, which is endemic to other mechanically cooled loca-
tions investigated in Malaysia and Japan, both in classrooms and
workplaces.
Using the data from this study, it was calculated that mean
comfort temperatures under FR and CL mode were 26.8 C and
25.6 C in Malaysia, and 25.1 C and 26.2 C in Japan, respectively.
These results are consistent with those from previous studies in
Malaysia and Japan and show that comfort temperatures could be
affected by geographical factors. However, other factors such as
gender characteristics and clothing insulation might be affecting
this result, due to the dominance of male respondents in the sample
in Japan and higher insulation of clothing worn by respondents in
Malaysia. Additionally, results from FR mode in Malaysia and Japan
were compatible with both CEN and ASHRAE standards. This shows
that it is possible to apply these standards in hot-humid climates,
despite having been developed for temperate climates.
Most comfort temperature results from CL mode in Malaysia
and Japan were within the CIBSE comfort zone guidelines, but a
number of points from both countries fell above the upper limit.
This might point to overcooling when using existing guidelines,
which could contribute to excessive energy consumption. Addi-
tionally, the current guideline for HVAC buildings might also un-
derestimate occupants' thermal preference in hot-humid climates,
where a greater degree of heat tolerance could be found in the
general population.
Most respondents in this study did not perform any thermal
adaptations over the observation period. However, the majority of
positive responses were from CL mode in Malaysia, where the
highest proportion of students reported adjusting AC systems to
alter their thermal environment. This is mainly due to both the
widespread availability of AC, the ease and effectiveness of this
adaptation method, and the fact that the students themselves are
not responsible for the bills incurred for AC use.
Funding
This research was supported by a Grant-in-Aid from the AUN/
SEED Net Collaborative Research Program (grant number 4B155) of
the Japan International Cooperation Agency (JICA), a matching
grant (grant number 00M44), and a research university grant (grant
number 11H67) from the Universiti Teknologi Malaysia.
Acknowledgements
We would like to thank all participants in the survey, as well as
the management and staff of the Universiti Teknologi Malaysia,
Universiti Teknologi MARA, and Kyushu University. Our sincere
appreciation is extended to Nur Atikah Shaari for her huge contri-
bution to data collection and Norakmal Affif Norizan for his help
during data processing.
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