scholarly journals Field Investigation of Indoor Thermal Performance in Malaysia Air-Welled Terraced House

2019 ◽  
Vol 6 (3) ◽  
pp. 33-41
Author(s):  
Pau Chung Leng ◽  
Roshida Abdul Majid ◽  
Noraslinda Abdul Rahman ◽  
Dilshan Remaz Ossen ◽  
Farhana Mohd Razif
Keyword(s):  
Air Temperature ◽  
Thermal Performance ◽  
Field Measurement ◽  
Cooling System ◽  
Tropical Climate ◽  
Weather Data ◽  
Vertical Position ◽  
Air Velocity ◽  
Humid Climate ◽  
Data Set

This paper aims to determine the performance of the air well system in a hot and humid tropical climate with existing full-scale air well of single-storey terraced house.  The application of air well in residential building widely applied in a traditional building, especially in the Middle East and Europe countries. However, resulted from the development, the application of passive cooling strategies such as air well is gradually replaced by a mechanical cooling system. The aim of the study is to investigate the cooling system role in tropics, where hot and humid climate the overheating of building interior are a critical dilemma due to solar penetration through building fenestration. A field measurement has been carried out in a single storey terraced house with built-in air well in Kuching, Sarawak for 5 days. The field measurement investigates the thermal performance of the single-storey terrace house air well under tropical context. The investigation was measured with U-12 HOBO data logger for temperature and humidity while the air velocity was measured with HD32.3 DeltaOhm measurement logger. Both types of the instrument placed in the air well in a vertical position while another U12 HOBO datalogger placed in a test room with window connected to air well.  The outdoor weather data set were measured with HOBO U30. Findings show that the under Malaysia tropical climate, the mean air velocity induced by the air well throughout the measurement days marked as 0.91m/s while during the hottest hour of the measurement days, the air velocity induced in the upper air well could reach 1.09m/s with an outdoor air temperature of 33.6°C and solar radiation of 198 Wh/m².  The findings of the study have explained the effectiveness of the air well in providing the thermal performance in the indoor environment and further study on modification of the air well configuration could enhance the airflow and air temperature

scholarly journals Indoor Thermal Performance of Ventilated Dwellings Using Fly Screens in the Hot-Humid Climate of Chennai, India

2009 ◽  
Vol 4 (2) ◽  
pp. 150-157 ◽  
Author(s):  
Vijayalaxmi J ◽  
S.P Sekar
Keyword(s):  
Solar Radiation ◽  
Air Temperature ◽  
Thermal Performance ◽  
Indoor Air ◽  
Tropical Climate ◽  
Summer Period ◽  
Humid Climate ◽  
Floor Area ◽  
Hot Humid Climate ◽  
Heating Up

In a hot-humid tropical climate, indoor thermal performance can be enhanced by comfort ventilation. Indoor ventilation depends upon building opening size. But risks involved in providing openings include ingress of mosquitoes and insects which thrive in the tropical climate. A practical and prevalent option to prevent insects in ventilated dwellings of the tropical, hot-humid city of Chennai, India is through the use of fly screens. Fly screens, when used over openings, prevent a certain quantum of solar radiation and wind from entering inside the rooms. Reduced direct solar radiation prevents the indoors from heating up, while reduced wind movement prevents the cross ventilation. Therefore, it is important to know the indoor thermal performance of ventilated rooms in the presence of fly screens with changing opening sizes. The criterion to evaluate indoor thermal performance in this paper is indoor air temperature. The aim of this research is to investigate the influence of fly screens on openings with varying sizes, in a naturally ventilated dwelling in the hot-humid climate of Chennai, India, during the summer period. The results of the study show that fly screens raise the indoor air temperature when openings are in the range of 100% to 35% of the room floor area. There is no significant change in the indoor air temperature when the opening sizes are less than 30% of the room floor area.

scholarly journals Thermal Performance of Single-Story Air-Welled Terraced House in Malaysia: A Field Measurement Approach

2020 ◽  
Vol 13 (1) ◽  
pp. 201
Author(s):  
Pau Chung Leng ◽  
Gabriel Hoh Teck Ling ◽  
Mohd Hamdan Ahmad ◽  
Dilshan Remaz Ossen ◽  
Eeydzah Aminudin ◽  
...  
Keyword(s):  
Relative Humidity ◽  
Air Temperature ◽  
Thermal Performance ◽  
Field Measurement ◽  
Natural Ventilation ◽  
Residential Buildings ◽  
Wet Bulb Globe Temperature ◽  
Natural Lighting ◽  
Ventilation Performance ◽  
Globe Temperature

The provision requirement of 10% openings of the total floor area stated in the Uniform Building By-Law 1984 Malaysia is essential for natural lighting and ventilation purposes. However, focusing on natural ventilation, the effectiveness of thermal performance in landed residential buildings has never been empirically measured and proven, as most of the research emphasized simulation modeling lacking sufficient empirical validation. Therefore, this paper drawing on field measurement investigates natural ventilation performance in terraced housing with an air-well system. The key concern as to what extent the current air-well system serving as a ventilator is effective to provide better thermal performance is to be addressed. By adopting an existing single-story air-welled terrace house, indoor environmental conditions and thermal performance were monitored and measured using HOBO U12 air temperature and humidity, the HOBO U12 anemometer, and the Delta Ohm HD32.3 Wet Bulb Globe Temperature meter for a six-month duration. The results show that the air temperature of the air well ranged from 27.48 °C to 30.92 °C, with a mean relative humidity of 72.67% to 79.25%. The mean air temperature for a test room (single-sided ventilation room) ranged from 28.04 °C to 30.92 °C, with a relative humidity of 70.16% to 76.00%. These empirical findings are of importance, offering novel policy insights and suggestions. Since the minimum provision of 10% openings has been revealed to be less effective to provide desirable thermal performance and comfort, mandatory compliance with and the necessity of the bylaw requirement should be revisited.

Experimental Validation and Design Simulations of a Passive Two-Phase Cooling System for Datacenters

2020 ◽  
Author(s):  
Jackson B. Marcinichen ◽  
John R. Thome ◽  
Raffaele L. Amalfi ◽  
Filippo Cataldo
Keyword(s):  
Thermal Performance ◽  
Experimental Validation ◽  
Cooling System ◽  
Electronics Cooling ◽  
Operating Conditions ◽  
Two Phase ◽  
Data Set ◽  
Pressure Drops ◽  
Wide Range ◽  
Important Challenge

Abstract Thermosyphon cooling systems represent the future of datacenter cooling, and electronics cooling in general, as they provide high thermal performance, reliability and energy efficiency, as well as capture the heat at high temperatures suitable for many heat reuse applications. On the other hand, the design of passive two-phase thermosyphons is extremely challenging because of the complex physics involved in the boiling and condensation processes; in particular, the most important challenge is to accurately predict the flow rate in the thermosyphon and thus the thermal performance. This paper presents an experimental validation to assess the predictive capabilities of JJ Cooling Innovation’s thermosyphon simulator against one independent data set that includes a wide range of operating conditions and system sizes, i.e. thermosyphon data for server-level cooling gathered at Nokia Bell Labs. Comparison between test data and simulated results show good agreement, confirming that the simulator accurately predicts heat transfer performance and pressure drops in each individual component of a thermosyphon cooling system (cold plate, riser, evaporator, downcomer (with no fitting parameters), and eventually a liquid accumulator) coupled with operational characteristics and flow regimes. In addition, the simulator is able to design a single loop thermosyphon (e.g. for cooling a single server’s processor), as shown in this study, but also able to model more complex cooling architectures, where many thermosyphons at server-level and rack-level have to operate in parallel (e.g. for cooling an entire server rack). This task will be performed as future work.

scholarly journals Seasonal Patterns of Spore Dispersal of Phaeosphaeria spp. and Stagonospora spp.

Plant Disease ◽  
1998 ◽  
Vol 82 (2) ◽  
pp. 187-194 ◽  
Author(s):  
E. Arseniuk ◽  
T. Góral ◽  
A. L. Scharen
Keyword(s):  
Multiple Regression ◽  
Air Temperature ◽  
Regression Models ◽  
Cross Validation ◽  
Weather Data ◽  
Time Interval ◽  
Weather Factors ◽  
Airborne Spores ◽  
Data Set ◽  
Microscope Slides

The spatial and temporal patterns of discharge and dissemination of airborne spores of Phaeosphaeria spp. and Stagonospora spp. were studied. Both ascospores and pycnidiospores of the pathogens were deposited at various densities on microscope slides used as spore samplers. The maximum deposition of the spores was observed during the period of August to October. A multiple regression analysis was used to determine which weather factors significantly explained the variation measured in the numbers of ascospores that settled on microscope slides. Rainfall, air temperature, and relative air humidity were influential in the release of Phaeosphaeria spp. ascospores into the air. The amount of airborne ascospores was a function of the variables and remained largely under their control. The liberation of ascospores was favored by air temperature above 0°C, rainfall greater than 1 mm, and high relative humidity. The range of atmospheric conditions stimulating air dispersal of ascospores was wider than that for pycnidiospores. Pycnidiospores were sampled only during rainy days. Their release was affected adversely by air temperature below 5°C. Multiple regression models based on weather data were developed and verified for their predictive ability and accuracy by jackknife and cross-validation procedures, as well as by comparisons of observed and predicted mean numbers of deposited ascospores per microscope slide after a substitution of each period data set with a set of data of the other respective time interval. The numbers of airborne ascospores predicted by the regression models were in a good agreement with the observed values. The jackknife and cross-validation techniques allowed use of the limited data sets for both the parameter estimation and validation processes in a development of simulation models. The airborne inoculum appeared to be omnipresent over cereal areas year round, except during periods with freezing temperatures and a snow cover. Such an omnipresence of inoculum of the pathogens poses a danger to crops and could be of importance in the epidemiology of Stagonospora (= Septoria) blotches under the climatic conditions of central Poland.

scholarly journals Influence of Courtyard Ventilation on Thermal Performance of Office Building in Hot-Humid Climate: A Case Study

2018 ◽  
Vol 34 ◽  
pp. 02053
Author(s):  
Esra’a Sh. Abbaas ◽  
Ala’eddin A. Saif ◽  
MAC Munaaim ◽  
Md. Azree Othuman Mydin
Keyword(s):  
Relative Humidity ◽  
Air Temperature ◽  
Thermal Performance ◽  
Natural Ventilation ◽  
Office Building ◽  
Humid Climate ◽  
Airborne Pollutants ◽  
Indoor Sources ◽  
Hot Humid Climate

The influence of courtyard on the thermal performance of Development Department office building in University Malaysia Perlis (UniMAP, Pauh Putra campus) is investigated through simulation study for the effect of ventilation on indoor air temperature and relative humidity of the building. The study is carried out using EnergyPlus simulator interface within OpenStudio and SketchUp plug in software to measure both of air temperature and relative humidity hourly on 21 April 2017 as a design day. The results show that the ventilation through the windows facing the courtyard has sufficient effect on reducing the air temperature compared to the ventilation through external windows since natural ventilation is highly effective on driving the indoor warm air out to courtyard. In addition, the relative humidity is reduced due to ventilation since the courtyard has high ability to remove or dilute indoor airborne pollutants coming from indoor sources. This indicates that the presence of courtyard is highly influential on thermal performance of the building.

scholarly journals Thermal Performance of Single-Storey Air-welled Terraced House in Malaysia: A Field Measurement Approach

2020 ◽  
Author(s):  
Pau Chung Leng ◽  
Mohd Hamdan Ahmad ◽  
Dilshan Remaz Ossen ◽  
Gabriel Hoh Teck Ling ◽  
Eeydzah Aminudin ◽  
...  
Keyword(s):  
Relative Humidity ◽  
Air Temperature ◽  
Thermal Performance ◽  
Field Measurement ◽  
Natural Ventilation ◽  
Heat Dissipation ◽  
Residential Buildings ◽  
High Energy ◽  
Existing Building ◽  
The Mean

The provision requirement of 10% openings of the total floor area stated in the Uniform Building by Law 1984 Malaysia has been practiced by designers for building plan submission approval. However, the effectiveness of thermal performance in landed residential buildings, despite the imposition by the by-law, has never been empirically measured and proven. Although terraced houses in Malaysia have dominated 40.9% of the total property transaction in 2019, such mass production with typical designs hardly provides its occupants with thermal comfort due to the static outdoor air condition and lack of external windows, where the conventional ventilation technique does not work well, even for houses with an air well system. Consequently, the occupants need to rely on mechanical cooling, which is a high energy-consuming component contributing to outdoor heat dissipation and therefore urban heat island effect. Thus, encouraging more effective natural ventilation to eliminate excessive heat from the indoor environment is critical. Since most of the research focuses on simulation modelling lacking sufficient empirical validation, this paper drawing on field measurement investigates natural ventilation performance in terraced housing with an air well system. More importantly, the key concern as to what extent the current air well system serving as a ventilator is effective to provide better thermal performance in the single storey terraced house is to be addressed. By adopting an existing single storey air welled terrace house, the existing indoor environmental conditions and thermal performance were monitored and measured using scientific equipment, namely HOBO U12 air temperature and air humidity, the HOBO U12 anemometer and the Delta Ohm HD32.3 Wet Bulb Globe Temperature meter for a six-month duration. The findings show that the air temperature of the air well ranged from 27.48°C to 30.92°C, while the mean relative humidity were from 72.67% to 79.25%. The mean air temperature for a test room (single sided ventilation room) ranged from 28.04°C to 30.92°C with a relative humidity of 70.16% to 76%. These empirical findings are of importance, offering novel policy insights and suggestions to potentially revising the existing building code standard and by laws; since the minimum provision of 10% openings has been revealed to be less effective to provide a desired thermal performance and comfort, mandatory compliance with, and the necessity for, the bylaw requirement should be revisited and further studied.

scholarly journals Thermal Performance of Vertical Courtyard System in Office Buildings Under Typical Hot Days in Hot-Humid Climate Area: A Case Study

2020 ◽  
Vol 12 (7) ◽  
pp. 2591
Author(s):  
Jin Wei ◽  
Fangsi Yu ◽  
Haixiu Liang ◽  
Maohui Luo
Keyword(s):  
Air Temperature ◽  
Thermal Performance ◽  
Weather Conditions ◽  
Office Buildings ◽  
Radiation Environment ◽  
Humid Climate ◽  
Hot Days ◽  
Cooling Effects ◽  
Hot Humid Climate

Due to the different types of courtyards in vertical courtyard system (VCS), their impacts on thermal performance in office buildings may vary. To better understand this issue, this paper investigates the thermal performance impact of three typical vertical courtyards. A field case study was conducted in VCSs during two typical extreme hot days under hot-humid climate conditions. The results show that the vertical courtyards have significant cooling effects under hot-humid climatic conditions. Via testing on linear, integrated, and rooftop courtyard with fusion layout, the fusion one has an obviously positive impact on air temperature reduction (4.3 °C). Compared with the linear and integrated courtyards, the maximum air temperature difference of fusion layout is around 1.6 °C. The thermal radiation environment of the fusion layout was better than that of the other two (linear and integrated). Besides, the surface temperature of the pavements (wood panel) in the vertical courtyards can reach 47 °C, while the vegetation can lower it by 8 °C under the same weather conditions. These findings show that the courtyard with fusion layout is more suitable for extreme hot weather conditions.

scholarly journals THE EFFECTS OF VARIOUS OPENING SIZES AND CONFIGURATIONS TO AIR FLOW DISPERSION AND VELOCITY IN CROSS-VENTILATED BUILDING

2020 ◽  
Vol 82 (4) ◽  
Author(s):  
Wardah Fatimah Mohammad Yusoff
Keyword(s):  
Numerical Simulation ◽  
Wind Speed ◽  
Indoor Air ◽  
Field Measurement ◽  
Air Flow ◽  
Flow Distribution ◽  
Air Velocity ◽  
Humid Climate ◽  
Venturi Effect ◽  
Natural Cross

The application of natural cross-ventilation in buildings located in the area where the wind speed is low is such a challenge. In hot and humid climate, sufficient air velocity is necessary in providing thermal comfort. Hence, this study intends to investigate the possibility of enhancing the indoor air velocity and flow distribution by employing the Venturi effect at the openings. Two research methods were applied namely field measurement and numerical simulation. The field measurement was executed at a single zone cross-ventilated building. Its purpose is to validate the numerical simulation steps and procedures. Meanwhile, investigations of the air velocity and flow distribution were conducted using ANSYS FLUENT CFD software. The findings indicate that the Venturi effect did occur at the openings. Providing a confined area at the inlet may enhance the Venturi effect, thus increasing the indoor air velocity. Based on the investigated scenario, it is found that the highest indoor air velocity of 0.2 m/s was achieved for the 75 % opening size with 1.5 m projection. This value indicated enhancement as the outdoor air velocity near the inlet was around 0.14 m/s only. The findings also indicate that the indoor air flow distribution of high air velocity focused more at the area of flow path between the inlet and outlet. The findings can be as guidance in enhancing the natural cross-ventilation in buildings especially that are located at the area where the wind speed is low. Nevertheless, the findings are limited to low-rise building with such opening configuration. Further study needs to be executed to determine the effects to other opening configurations and building heights. 

scholarly journals Long-Term Weather Data Measurements From A Danish Climate Station And The Weather’s Influence On The Thermal Performance Of Solar Collectors

2015 ◽  
Vol 23 (2) ◽  
pp. 23-29
Author(s):  
Lukáš Skalík
Keyword(s):  
Air Temperature ◽  
Thermal Performance ◽  
Global Radiation ◽  
Diffuse Radiation ◽  
Ambient Air ◽  
Energy Output ◽  
Weather Data ◽  
Solar Collectors ◽  
Ambient Air Temperature ◽  
Climate Station

Abstract A weather data evaluation from a climate station in Lyngby, Denmark, was carried out. Twenty years of measurements show that the increase in global radiation was almost 3.5 kWh/m2 per year, corresponding to a growth of the yearly global radiation of 7 % for the last 20 years. The global radiation variation between the least sunny year to the sunniest year was 20%. The increase in diffuse radiation was 1.9 kWh/m2 per year, corresponding to 20 years’ growth of up to 7 %. The annual diffuse radiation of nearly 19 % varied from the least cloudy year to the cloudiest year. A small increase was measured for the ambient air temperature. The measurements showed a yearly increase of 0.04 K per year. The average yearly ambient air temperature variation from the coldest to the warmest year was 3.1 K. According to the seasonal growth of the parameters measured, the ambient air temperature and diffuse radiation increased the most in the summer period, while the global radiation significantly increased in the spring months. The calculations of the solar collector's thermal performance in Lyngby showed that the energy output was mostly dependent on beam radiation. The ambient air temperature did not have a high influence on the thermal performance of the solar collectors compared to the influence of the total solar radiation.

scholarly journals Influence of Ambient Air Velocity Orientation in Thermal Behaviour of Open Refrigerated Display Cabinets

2010 ◽  
Author(s):  
Pedro Dinis Gaspar ◽  
L. C. Carrilho Gonc¸alves ◽  
Xiao Ge
Keyword(s):  
Thermal Behaviour ◽  
Air Temperature ◽  
Thermal Performance ◽  
Air Flow ◽  
Experimental Tests ◽  
Ambient Air ◽  
Air Velocity ◽  
Cfd Modelling ◽  
Air Curtain ◽  
Numerical Predictions

Open refrigerated display cabinets (ORDCs) suffer alterations of their thermal behaviour and of its performance due to variations of ambient air conditions (air temperature, relative humidity and velocity magnitude and orientation). Some factors interfere and affect the re-circulated air curtain behaviour and thus the equipment’s overall thermal performance. Examples of these factors are the location of air conditioning system discharge grilles, air mass flows originated by pressure differences due to openings to surroundings, and ambient air flow instabilities due to consumers’ passage nearby the frontal opening of the display cabinet, among others. This work performs a three-dimensional (3D) Computational Fluid Dynamics (CFD) modelling of air flow and heat transfer in an ORDC. The influence of ambient air velocity orientation in performance of the re-circulated air curtain is evaluated. A CFD parametric study is developed considering the ambient air orientation parallel, oblique and perpendicular to the frontal opening plane of the equipment. The 3D effects of ambient air velocity orientation are determined through the analysis of air temperature and velocity inside the equipment as well as along and across the air curtain. The longitudinal air flow oscillations and length extremity effects are analyzed, having a considerable influence in the overall thermal performance of the equipment. Experimental tests following EN-ISO Standard 23953 were conducted for climatic class n.er 3 (Tamb = 25 °C, φamb = 60%) in order to characterize the phenomena near inlets, outlets and physical borders. Moreover, experimental data is used to prescribe boundary conditions as well as to validate numerical predictions of temperature and velocity distributions.

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