Displaying publications 1 - 20 of 22 in total

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  1. Yong HH, Foong K, Borland R, Omar M, Hamann S, Sirirassamee B, et al.
    Asia Pac J Public Health, 2010 Jan;22(1):98-109.
    PMID: 20032039 DOI: 10.1177/1010539509351303
    This study examined support for and reported compliance with smoke-free policy in air-conditioned restaurants and other similar places among adult smokers in Malaysia and Thailand. Baseline data (early 2005) from the International Tobacco Control Southeast Asia Survey (ITC-SEA), conducted face-to-face in Malaysia and Thailand (n = 4005), were used. Among those attending venues, reported total smoking bans in indoor air-conditioned places such as restaurants, coffee shops, and karaoke lounges were 40% and 57% in Malaysia and Thailand, respectively. Support for a total ban in air-conditioned venues was high and similar for both countries (82% Malaysian and 90% Thai smokers who believed there was a total ban), but self-reported compliance with bans in such venues was significantly higher in Thailand than in Malaysia (95% vs 51%, P < .001). As expected, reporting a ban in air-conditioned venues was associated with a greater support for a ban in such venues in both countries.
    Matched MeSH terms: Air Conditioning
  2. Yau YH, Chew BT
    Indoor Air, 2009 Dec;19(6):500-10.
    PMID: 19719535 DOI: 10.1111/j.1600-0668.2009.00617.x
    This article presents findings of the thermal comfort study in hospitals. A field survey was conducted to investigate the temperature range for thermal comfort in hospitals in the tropics. Thermal acceptability assessment was conducted to examine whether the hospitals in the tropics met the ASHRAE Standard-55 80% acceptability criteria. A total of 114 occupants in four hospitals were involved in the study. The results of the field study revealed that only 44% of the examined locations met the comfort criteria specified in ASHRAE Standard 55. The survey also examined the predicted percentage of dissatisfied in the hospitals. The results showed that 49% of the occupants were satisfied with the thermal environments in the hospitals. The field survey analysis revealed that the neutral temperature for Malaysian hospitals was 26.4 degrees C. The comfort temperature range that satisfied 90% of the occupants in the space was in the range of 25.3-28.2 degrees C. The results from the field study suggested that a higher comfort temperature was required for Malaysians in hospital environments compared with the temperature criteria specified in ASHRAE Standard (2003). In addition, the significant deviation between actual mean vote and predicted mean vote (PMV) strongly implied that PMV could not be applied without errors in hospitals in the tropics.
    Matched MeSH terms: Air Conditioning/standards*
  3. Shodiya, S., Azhar, A. A., Darus, A. N.
    MyJurnal
    HCFCs, in addition to destroying the ozone layer, have been recognized as a contributing factor that increases global warming. It is widely used as working fluid in window air-conditioning system, where capillary tube serves as an expansion device. Literature reports have shown that no single refrigerant can solve the problem of ozone layer depletion and global warming. Refrigerant HC290/HC600a/HFC407C mixture, an eco-friendly refrigerant, has been recognized as an alternative to HCFC22. The objective of this study is to, for cost effectiveness, develop an empirical correlation to predict the refrigerant HC290/ HC600a/HFC407C mixture mass flow rate using statistical experimental design approach. A review of relevant literature shows that refrigerant’s mass flow rate depends on condensing temperature, degree of subcooling, inner diameter and length of capillary tube. The relationship between the mass flow rate and the four independent variables was established as an empirical mathematical correlation using central composite design (CCD), a response surface methodology (RSM). This empirical correlation was examined using analysis of variance (ANOVA) of 5% level of significance. The results of these analysis showed that the correlation fitted well with the experimental data yielding an average and standard deviation of 1.05% and 2.62%, respectively. The validity of the present correlation was further assessed by comparing it with published empirical correlation in literature and the result showed that the present correlation is consistent.
    Matched MeSH terms: Air Conditioning
  4. Salamone F, Belussi L, Danza L, Galanos T, Ghellere M, Meroni I
    Sensors (Basel), 2017 May 04;17(5).
    PMID: 28471398 DOI: 10.3390/s17051021
    The article describes the results of the project "open source smart lamp" aimed at designing and developing a smart object able to manage and control the indoor environmental quality (IEQ) of the built environment. A first version of this smart object, built following a do-it-yourself (DIY) approach using a microcontroller, an integrated temperature and relative humidity sensor, and techniques of additive manufacturing, allows the adjustment of the indoor thermal comfort quality (ICQ), by interacting directly with the air conditioner. As is well known, the IEQ is a holistic concept including indoor air quality (IAQ), indoor lighting quality (ILQ) and acoustic comfort, besides thermal comfort. The upgrade of the smart lamp bridges the gap of the first version of the device providing the possibility of interaction with the air exchange unit and lighting system in order to get an overview of the potential of a nearable device in the management of the IEQ. The upgraded version was tested in a real office equipped with mechanical ventilation and an air conditioning system. This office was occupied by four workers. The experiment is compared with a baseline scenario and the results show how the application of the nearable device effectively optimizes both IAQ and ILQ.
    Matched MeSH terms: Air Conditioning
  5. Rosli Abu Bakar, Ahmad Rasdan Ismail, Norfadzilah Jusoh, Abdul Mutalib Leman
    MyJurnal
    This paper discuss thermal comfort studies of an under air conditioning in hot and humid climate which at one of the higher institution in East Coast of Malaysia. Indoor thermal environment is important as it affects the health and productivity of building occupants. The paper reports on an experimental investigation of indoor thermal comfort characteristics under the control of air conditioning. Firstly, the well known Fanger’s thermal comfort model was simplified for the current experimental investigation. This is followed by reporting the experimental results of indoor thermal comfort characteristics under the control of temperature, with eight different of temperatures which are 22oC to 29oC. Finally, indoor thermal comfort was merely affected by the increment ventilation and outdoor climate. PMV value was higher when near from the window because of the effects of the wall radiations and the metabolic heat.
    Matched MeSH terms: Air Conditioning
  6. Pau, J.S., Pao, William K.S., Shaharin A. Sulaiman, Halawa, E.
    MyJurnal
    Unnecessary air conditioning for thermal comfort causeds energy over consumption. As air conditioning has become irreversible, one of the solutions is to run air conditioners at minimal energy without sacrificing the comfort of occupants in air conditioned space. The approach to thermal comfort is the key to successful thermal comfort research. Fanger's model has been adopted by ASHRAE and ISO standards but its universal applications have been debated. In recent decades, adaptive model that regards humans as adaptive beings has been accepted. The static and deterministic nature of Fanger's model has limited its application in hot, humid countries, such as Malaysia. This research aims to integrate the theories of Fanger and adaptive model into a new model which is applicable in Malaysia by taking the case in lecture halls. The new Fanger's Adaptive Model is established through normalization of the thermal sensation distribution obtained in thermal chamber by Fanger. The PMV range of 80% satisfaction has been widened to -1.3 to +1.3 which adopted the theories of adaptive model, where humans have the ability to adapt to environment. The research also includes field observations on Malaysian students clothing and activity levels in lecture halls. Previous field study results which proposed 25.3°C comfort temperature for lecture halls in Malaysia together with the field observation results were used to verify the new model. About 95% of PMV falls within the new range at this comfort temperature. It is proven that Fanger's model is semi-adaptive and probabilistic and the integration of Fanger's Adaptive Model is more accurate in predicting thermal comfort in hot and humid climate.
    Matched MeSH terms: Air Conditioning
  7. Nur Azfahani Ahmad, Zuraihana Ahmad Zawawi, Nazhatulzalkis Jamaludin, Khairulliza Ahmad Salleh
    Jurnal Inovasi Malaysia, 2019;2(2):55-70.
    MyJurnal
    A 1984 World Health Organization (WHO) Committee report highlighted that up to 30 per cent of buildings may have to face problems related to Indoor Air Quality (IAQ). Insufficient ventilation will lead to stagnant air and can cause stuffiness in buildings. This will then leads to a bigger problem, known as the Sick Building Syndrome (SBS). It is important to note that sick building syndrome may cause various illnesses including allergies, acute respiration problem, feeling of discomfort and other psychological impacts. The “Ventilation Flow Evaluation System for Sustainable Housing Development” is a PC-based database tool developed to access and measure ventilation flow in a new or remodelled building in order to prevent or mitigate this problem. The purpose of the system is to provide resources for building designers in solving Indoor Air Quality (IAQ) issues especially related to ventilation flow based on regulations provided in Malaysian Standard (MS 1525). The system will allow readily building plan to be measured and analysed based on ventilation data collected at site, in order to allow buildings to obtain healthy and sufficient air for breathing and comfort purposes. The system will also recommend suitable layout plan in the building to meet the ventilation purposes, namely cross-ventilation and stack-effect ventilation.
    Matched MeSH terms: Air Conditioning
  8. Nor Mohd Razif Noraini, Leman, A.M., Ahmad Sayuti Zainal Abidin
    MyJurnal
    A preliminary study has been conducted in a new constructed 8 stories building (2 level of Hostels facility, 3 level of Training Room, 2 Level of Offices and 1 level of Exhibition Halls and Rooms) in Bandar Baru Bangi, Selangor. The Hostels facility is a floor tile and furnished with build in locker and use split air conditioning system while the Training Room and Exhibition Rooms used floor tile. The Offices and Exhibition Hall are carpeted furnished. All these spaces were using centralized air conditioning systems. A pre-commissioning assessment on 5 chemical parameters of indoor air pollutants such Total Volatile Organic Compounds (TVOC), Formaldehyde, Respirable Particulates (PM!
    Matched MeSH terms: Air Conditioning
  9. Ngah Nasaruddin A, Tee BT, Mohd Tahir M, Md Jasman MES
    Data Brief, 2021 Apr;35:106797.
    PMID: 33614870 DOI: 10.1016/j.dib.2021.106797
    Exposure to hot and humid weather conditions will often lead to consuming a vast amount of electricity for cooling. Heating, ventilation, and air conditioning (HVAC) systems are customarily known as the largest consumers of energy in institutions and other facilities which raises the question regarding the impact of the weather conditions to the amount energy consumed. The academic building is a perfect example where a constant fixed daily operating characteristic is measured by the hour, aside from the occasional semester break. Therefore, it can be assumed that the daily HVAC services on an academic facility will operate on a fixed schedule each day, having a similar pattern all year round. This article aims to present an analysis on the relationship between typical weather data by implying the test reference year (TRY) and academic building electricity consumption in an academic building located at Durian Tunggal, Melaka. Typical weather data were generated in representing the weather data between 2010 and 2018 using the Finkelstein-Schafer statistic (F-S statistic) in addition to a data set of electricity consumption. Descriptive analysis and correlation matrix analysis were conducted using JASP software for two sets of sample data; Set A and Set B, with data points of 12 and 108, respectively. The result showed an alternate result with a positive correlation between 1)mean temperature-electricity consumption, and 2)mean rainfall-electricity consumption for data Set A, and a negative correlation between 1)mean temperature-electricity consumption and 2)mean rainfall-electricity consumption for data Set B.
    Matched MeSH terms: Air Conditioning
  10. Loo HS, Yeow PH
    Appl Ergon, 2015 Nov;51:383-91.
    PMID: 26154237 DOI: 10.1016/j.apergo.2015.06.007
    The research aims to address the physically loading task and quality and productivity problems in the brazing of coils of air-handler units. Eight operators participated in two intervention studies conducted in a factory in Malaysia to compare the status quo brazing with (1) the use of a new twin-brazing torch that replaced the single-brazing gun and (2) brazing in a sitting position. The outcome measures are related to quality, productivity, monetary costs, body postures and symptoms. After baseline, Interventions I and II were applied for 3 months respectively. The results show a 58.9% quality improvement, 140% productivity increase and 113 times ROI. There was also a reduction in poor work postures e.g. in the raising of the arms and shoulders; bending, twisting and extending of the neck; and bending of left and right wrists, and the back. This research can be replicated in other factories that share similar processes.
    Matched MeSH terms: Air Conditioning
  11. Kumara TK, Hassan AA, Salmah MR, Bhupinder S
    PMID: 23691627
    The larval growth of Liosarcophaga dux Thompson (Diptera: Sarcophagidae) was studied under varying indoor room temperatures in Malaysia. Five replicates were established. The immature growth of this species from first instar until adult emergence was 307.0+/-3.0 hours. The mean larval length measured for second instar, third instar, post-feeding stage and puparia were 6.5+/-0.5 mm (n=10), 11.8+/-3.7 mm (n=31), 12.7+/-0.8 mm (n=16), and 9.5+/-0.5 mm (n=15), respectively.
    Matched MeSH terms: Air Conditioning
  12. Ilyas M
    Med J Malaysia, 1980 Dec;35(2):131-3.
    PMID: 7266405
    Matched MeSH terms: Air Conditioning
  13. Hariri A, Mohamad Noor N, Paiman NA, Ahmad Zaidi AM, Zainal Bakri SF
    Int J Occup Saf Ergon, 2018 Dec;24(4):646-651.
    PMID: 28849717 DOI: 10.1080/10803548.2017.1368950
    Welding operations are rarely conducted in an air-conditioned room. However, a company would set its welding operations in an air-conditioned room to maintain the humidity level needed to reduce hydrogen cracks in the specimen being welded. This study intended to assess the exposure to metal elements in the welders' breathing zone and toenail samples. Heavy metal concentration was analysed using inductively coupled plasma mass spectrometry. The lung function test was also conducted and analysed using statistical approaches. Chromium and manganese concentrations in the breathing zone exceeded the permissible exposure limit stipulated by Malaysian regulations. A similar trend was obtained in the concentration of heavy metals in the breathing zone air sampling and in the welders' toenails. Although there was no statistically significant decrease in the lung function of welders, it is suggested that exposure control through engineering and administrative approaches should be considered for workplace safety and health improvement.
    Matched MeSH terms: Air Conditioning
  14. González-Briones A, Prieto J, De La Prieta F, Herrera-Viedma E, Corchado JM
    Sensors (Basel), 2018 Mar 15;18(3).
    PMID: 29543729 DOI: 10.3390/s18030865
    At present, the domotization of homes and public buildings is becoming increasingly popular. Domotization is most commonly applied to the field of energy management, since it gives the possibility of managing the consumption of the devices connected to the electric network, the way in which the users interact with these devices, as well as other external factors that influence consumption. In buildings, Heating, Ventilation and Air Conditioning (HVAC) systems have the highest consumption rates. The systems proposed so far have not succeeded in optimizing the energy consumption associated with a HVAC system because they do not monitor all the variables involved in electricity consumption. For this reason, this article presents an agent approach that benefits from the advantages provided by a Multi-Agent architecture (MAS) deployed in a Cloud environment with a wireless sensor network (WSN) in order to achieve energy savings. The agents of the MAS learn social behavior thanks to the collection of data and the use of an artificial neural network (ANN). The proposed system has been assessed in an office building achieving an average energy savings of 41% in the experimental group offices.
    Matched MeSH terms: Air Conditioning
  15. Dahlan ND, Gital YY
    Appl Ergon, 2016 May;54:169-76.
    PMID: 26851476 DOI: 10.1016/j.apergo.2015.12.008
    The study was done to identify affective and sensory responses observed as a result of hysteresis effects in transient thermal conditions consisting of warm-neutral and neutral - warm performed in a quasi-experiment setting. Air-conditioned building interiors in hot-humid areas have resulted in thermal discomfort and health risks for people moving into and out of buildings. Reports have shown that the instantaneous change in air temperature can cause abrupt thermoregulation responses. Thermal sensation vote (TSV) and thermal comfort vote (TCV) assessments as a consequence of moving through spaces with distinct thermal conditions were conducted in an existing single-story office in a hot-humid microclimate, maintained at an air temperature 24 °C (± 0.5), relative humidity 51% (± 7), air velocity 0.5 m/s (± 0.5), and mean radiant temperature (MRT) 26.6 °C (± 1.2). The measured office is connected to a veranda that showed the following semi-outdoor temperatures: air temperature 35 °C (± 2.1), relative humidity 43% (± 7), air velocity 0.4 m/s (± 0.4), and MRT 36.4 °C (± 2.9). Subjective assessments from 36 college-aged participants consisting of thermal sensations, preferences and comfort votes were correlated against a steady state predicted mean vote (PMV) model. Local skin temperatures on the forehead and dorsal left hand were included to observe physiological responses due to thermal transition. TSV for veranda-office transition showed that no significant means difference with TSV office-veranda transition were found. However, TCV collected from warm-neutral (-0.24, ± 1.2) and neutral-warm (-0.72, ± 1.3) conditions revealed statistically significant mean differences (p < 0.05). Sensory and affective responses as a consequence of thermal transition after travel from warm-neutral-warm conditions did not replicate the hysteresis effects of brief, slightly cool, thermal sensations found in previous laboratory experiments. These findings also indicate that PMV is an acceptable alternative to predict thermal sensation immediately after a down-step thermal transition (≤ 1 min exposure duration) for people living in a hot-humid climate country.
    Matched MeSH terms: Air Conditioning/adverse effects*; Air Conditioning/methods
  16. Chowdhury MEH, Khandakar A, Ahmed S, Al-Khuzaei F, Hamdalla J, Haque F, et al.
    Sensors (Basel), 2020 Oct 02;20(19).
    PMID: 33023097 DOI: 10.3390/s20195637
    Growing plants in the gulf region can be challenging as it is mostly desert, and the climate is dry. A few species of plants have the capability to grow in such a climate. However, those plants are not suitable as a food source. The aim of this work is to design and construct an indoor automatic vertical hydroponic system that does not depend on the outside climate. The designed system is capable to grow common type of crops that can be used as a food source inside homes without the need of large space. The design of the system was made after studying different types of vertical hydroponic systems in terms of price, power consumption and suitability to be built as an indoor automated system. A microcontroller was working as a brain of the system, which communicates with different types of sensors to control all the system parameters and to minimize the human intervention. An open internet of things (IoT) platform was used to store and display the system parameters and graphical interface for remote access. The designed system is capable of maintaining healthy growing parameters for the plants with minimal input from the user. The functionality of the overall system was confirmed by evaluating the response from individual system components and monitoring them in the IoT platform. The system was consuming 120.59 and 230.59 kWh respectively without and with air conditioning control during peak summer, which is equivalent to the system running cost of 13.26 and 25.36 Qatari Riyal (QAR) respectively. This system was circulating around 104 k gallons of nutrient solution monthly however, only 8-10 L water was consumed by the system. This system offers real-time notifications to alert the hydroponic system user when the conditions are not favorable. So, the user can monitor several parameters without using laboratory instruments, which will allow to control the entire system remotely. Moreover, the system also provides a wide range of information, which could be essential for plant researchers and provides a greater understanding of how the key parameters of hydroponic system correlate with plant growth. The proposed platform can be used both for quantitatively optimizing the setup of the indoor farming and for automating some of the most labor-intensive maintenance activities. Moreover, such a monitoring system can also potentially be used for high-level decision making, once enough data will be collected. This work presents significant opportunities for the people who live in the gulf region to produce food as per their requirements.
    Matched MeSH terms: Air Conditioning
  17. Chan LL, Mak JW, Low YT, Koh TT, Ithoi I, Mohamed SM
    Acta Trop, 2011 Jan;117(1):23-30.
    PMID: 20858455 DOI: 10.1016/j.actatropica.2010.09.004
    During a study on the quality of the indoor environment, Acanthamoeba spp. were detected in 20 out of 87 dust samples collected from air-conditioners installed in a four-story campus building located in Kuala Lumpur, Malaysia. Twenty-one cloned Acanthamoeba isolates designated as IMU1 to IMU21 were established from the positive primary cultures. Five species were identified from the 16 isolates according to the morphological criteria of Pussard and Pons; i.e. A. castellanii, A. culbertsoni, A. griffini, A. hatchetti and A. polyphaga. Species identities for the remaining five isolates (IMU4, IMU5, IMU15, IMU20 and IMU21), however, could not be determined morphologically. At genotypic characterization, these isolates were placed into T3 (IMU14); T5 (IMU16 and IMU17) and T4 (all the remaining isolates). To predict the potential pathogenicity of these Acanthamoeba isolates, thermo- and osmotolerance tests were employed; many isolates were predicted as potential human pathogens based on the outcome of these tests. This is the first time potentially pathogenic Acanthamoeba have been isolated from air-conditioners in Malaysia.
    Matched MeSH terms: Air Conditioning*
  18. Arsad FS, Hod R, Ahmad N, Baharom M, Ja'afar MH
    Environ Sci Pollut Res Int, 2023 Jun;30(29):73137-73149.
    PMID: 37211568 DOI: 10.1007/s11356-023-27089-9
    Thermal comfort is linked to our health, well-being, and productivity. The thermal environment is one of the main factors that influence thermal comfort and, consequently, the productivity of occupants inside buildings. Meanwhile, behavioural adaptation is well known to be the most critical contributor to the adaptive thermal comfort model. This systematic review aims to provide evidence regarding indoor thermal comfort temperature and related behavioural adaptation. Studies published between 2010 and 2022 examining indoor thermal comfort temperature and behavioural adaptations were considered. In this review, the indoor thermal comfort temperature ranges from 15.0 to 33.8 °C. The thermal comfort temperature range varied depending on several factors, such as climatic features, ventilation mode, type of buildings, and age of the study population. Elderly and younger children have distinctive thermal acceptability. Clothing adjustment, fan usage, AC usage, and open window were the most common adaptive behaviour performed. Evidence shows that behavioural adaptations were also influenced by climatic features, ventilation mode, type of buildings, and age of the study population. Building designs should incorporate all factors that affect the thermal comfort of the occupants. Awareness of practical behavioural adaptations is crucial to ensure occupants' optimal thermal comfort.
    Matched MeSH terms: Air Conditioning*
  19. Amir Abdullah, M.D., Leman, A.M., Norhidayah, A., Syafiq Syazwan, M.M.
    MyJurnal
    A poor Indoor Air Quality (IAQ) is a crucial problem which produces by the improper maintenance of Mechanical Ventilation and Air Conditioning (MVAC) ducting. A budget constraint intimidates for the practise of monitoring of the MVAC ducting. Thus IAQ measurements were conducted at the room where the air supplied by centralized air conditioning. It has been performed at four different offices that supply by two different Air Handling Unit (AHU). Walkthrough survey was conducted and the area samplings were selected for data collection. This paper examines the result of comparison of air ducting and air quality at academic office building, Universiti Tun Hussein Onn Malaysia (UTHM). The parameters involved were Temperature (°C), Relative Humidity (RH), Carbon Dioxide (CO2) and Carbon Monoxide (CO). Pictures were also captured to demonstrate the real conditions inside the ducting by using Mechanical Robot. Thus, duct cleaning was recommended to be an exceptional platform for the IAQ improvement.
    Matched MeSH terms: Air Conditioning
  20. Aliero MS, Pasha MF, Toosi AN, Ghani I
    Environ Sci Pollut Res Int, 2022 Dec;29(57):85727-85741.
    PMID: 35001275 DOI: 10.1007/s11356-021-17862-z
    The enforcement of the Movement Control Order to curtail the spread of COVID-19 has affected home energy consumption, especially HVAC systems. Occupancy detection and estimation have been recognized as key contributors to improving building energy efficiency. Several solutions have been proposed for the past decade to improve the precision performance of occupancy detection and estimation in the building. Environmental sensing is one of the practical solutions to detect and estimate occupants in the building during uncertain behavior. However, the literature reveals that the performance of environmental sensing is relatively poor due to the poor quality of the training dataset used in the model. This study proposed a smart sensing framework that combined camera-based and environmental sensing approaches using supervised learning to gather standard and robust datasets related to indoor occupancy that can be used for cross-validation of different machine learning algorithms in formal research. The proposed solution is tested in the living room with a prototype system integrated with various sensors using a random forest regressor, although other techniques could be easily integrated within the proposed framework. The primary implication of this study is to predict the room occupation through the use of sensors providing inputs into a model to lower energy consumption. The results indicate that the proposed solution can obtain data, process, and predict occupant presence and number with 99.3% accuracy. Additionally, to demonstrate the impact of occupant number in energy saving, one room with two zones is modeled each zone with air condition with different thermostat controller. The first zone uses IoFClime and the second zone uses modified IoFClime using a design-builder. The simulation is conducted using EnergyPlus software with the random simulation of 10 occupants and local climate data under three scenarios. The Fanger model's thermal comfort analysis shows that up to 50% and 25% energy can be saved under the first and third scenarios.
    Matched MeSH terms: Air Conditioning
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