scholarly journals AN IMPACT OF THE EFFICIENT FUNCTIONING OF THE VENTILATION AND AIR-CONDITIONING SYSTEM ON THERMAL COMFORT OF THE MEDICAL STAFF IN THE OPERATING ROOM

2016 ◽  
Vol 17 (5) ◽  
pp. 114-119 ◽  
Author(s):  
Tomasz Jankowski ◽  
Magdalena Młynarczyk
2014 ◽  
Vol 493 ◽  
pp. 74-79
Author(s):  
Y.A. Sabtalistia ◽  
S.N.N. Ekasiwi ◽  
B. Iskandriawan

Energy consumption for air conditioning systems (air conditioning system) increased along with the increasing need for fresh air and comfortable in the room especially apartments. FAC system (Floor Air Conditioning) is growing because it is more energy efficient than CAC (Ceiling Air Conditioning) system. However, the position of the AC supply is on the lower level at the FAC system causes draft discomfort becomes greater as air supply closer to the occupants so that thermal comfort can be reduced. Heat mixture of windows, exterior walls, kitchen, and occupants in the studio apartment affect thermal comfort in the room too.This study aims to determine the position of the AC supply which has the best thermal comfort of FAC system in the studio apartment. It can be done by analyzing ADPI (Air Diffusion Performance Index), the distribution of air temperature, wind speed, RH (Relative Humidity), and DR (Draft Risk) to change the position of the AC supply supported by CFD (Computational Fluid Dynamics) simulation.This result prove that AC position 2 (on wall near the kitchen) is more comfortable than AC position 1 (on the bathroom wall) because AC position 2 away from occupied areas, thereby reducing the occurrence of draught discomfort.


Author(s):  
Danial Mohammadi ◽  
Simin Nasrabadi

Background: One way to achieve a standard heating, ventilating, and air conditioning system with maximum satisfaction is to use a thermal index to identify and determine the thermal comfort of people. In this study we intend to evaluate thermal comfort based on PMV-PPD (Predicted Mean Vote/Predicted Percentage Dissatisfied) model in workers of screening center for COVID-19. Methods: The study period was from March 1 to October 31, 2020. In this study, we used the ISO 7730 model to determinate PMV-PPD index. PMV index was used to determine thermal comfort at different scales in Birjand city with arid and hot climate. All data were analyzed using R software (version 3.3.0) and IBM SPSS statistics softwares. Results: The maximum and minimum recorded physical PMV values in the study period were observed in June as (2.09 ± 0.03) and March as (-1.27 ± 0.14), respectively. The amplitude of the thermal sense in the study period was varied between slightly cool (-1.5) and warm (+2.5). The PPD in spring was 40% which indicated slightly warm to hot condition. Conclusions: The October was the only month during the study in which thermal stress was in comfort or neutral thermal condition.  Our results suggest that thermal comfort has dimensions and indices which are helpful in managing energy consumption.


Author(s):  
Somaye A. Mohamadi ◽  
Abdulraheem J. Ahmed

<span>Despite their complexity and uncertainty, air conditioning systems should provide the optimal thermal conditions in a building. These controller systems should be adaptable to changes in environmental parameters. In most air conditioning systems, today, there are On/Off controllers or PID in more advanced types, which, due to different environmental conditions, are not optimal and cannot provide the optimal environmental conditions. Controlling thermal comfort of an air conditioning system requires estimation of thermal comfort index. In this study, fuzzy controller was used to provide thermal comfort in an air conditioning system, and neural network was used to estimate thermal comfort in the feedback path of the controller. Fuzzy controller has a good response given the non-linear features of air conditioning systems. In addition, the neural network makes it possible to use thermal comfort feedback in a real-time control.</span>


Author(s):  
Ghezlane Halhoul Merabet ◽  
Mohamed Essaaidi ◽  
Driss Benhaddou

Thermal comfort is closely related to the evaluation of heating, ventilation, and air conditioning systems. It can be seen as the result of the perception of the occupants of a given environment, and it is the product of the interaction of a number of personal and environmental factors. Otherwise, comfort issues still do not play an important role in the daily operation of commercial buildings. However, in the workplace, local quality effects, in addition to the health, the productivity that has a significant impact on the performance of the activities. In this regard, researchers have conducted, for decades, investigations related to thermal comfort and indoor environments, which includes developing models and indices through experimentations to establish standards to evaluate comfort and factors and set-up parameters for heating, ventilation, and air conditioning systems. However, to our best knowledge, most of the research work reported in the literature deals only with parameters that are not dynamically tracked. This work aims to propose a prototype for comfort measuring through a wireless sensor network and then presenting a model for thermal comfort prediction. The developed model can be used to set up a heating, ventilation, and air conditioning system to meet the expected comfort level. In particular, the obtained results show that there is a strong correlation between users’ comfort and variables such as age, gender, and body mass index as a function of height and weight.


2013 ◽  
Vol 773 ◽  
pp. 883-888 ◽  
Author(s):  
Hamid Nawaz ◽  
Yan Sheng Yuan

The focus of this work is to simulate and optimize thermal comfort in a ship air-conditioning system by evaluating the performance of different types of air supply outlets. Thermal comfort analyses were performed in Solidworks Flow Simulation software by changing the number, type and position of air supply outlets and the comfort was optimized by evaluating the values of temperature, velocity, PMV (Predicted mean vote) & PPD (Predicted Percentage Dissatisfied). It was concluded from the results obtained from different analyses that air supply outlet is a vital part in any type of HVAC (Heating ventilation & air conditioning) system design, as its number, type and position has significant effect on the air distribution and thermal comfort in a subject space. It was also deduced that improper selection of air supply outlet can result in room air stagnation, unacceptable temperature gradients, and undesirable velocities in the occupied zone that may lead to occupant discomfort. Through this work the importance and effectiveness of CFD (computational fluid dynamics) design tools, in the design & optimization of HVAC systems has been evaluated and it was concluded that CFD design software like Solidworks flow simulation provide an excellent provision to validate different aspects of HVAC design before actual construction.


2014 ◽  
Vol 525 ◽  
pp. 588-592
Author(s):  
Zhang Yuan Wang ◽  
Xiang Mei Zhang ◽  
Wan Sheng Yang

Aim of the paper is to investigate the indoor thermal comfort of the buildings. This work is undertaken by the combination of the literature review and experimental measurement and analyses, on basis of the selected 12 public buildings in Dongguan City (Guangdong Province, China), located at the typical sub-tropic climatic region. It was found that when the air-conditioning system was turned off, the internal surface temperature of the insulation was above a control target of 30°C; when the air-conditioning system was turned on, the internal surface temperature of the insulation was below the control target of 30°C, meeting the requirement of the thermal comfort of human body in summer. These figures will be helpful in the determination of the quantitative control target to improve the indoor thermal comfort in the subtropical areas.


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