scholarly journals Hygrothermal study of dwelling submitted to passive cooling

2018 ◽  
Vol 22 (6 Part A) ◽  
pp. 2597-2604
Author(s):  
Razika Kharchi ◽  
Khaled Imessad
Keyword(s):  
Relative Humidity ◽  
Thermal Comfort ◽  
Air Conditioning ◽  
Natural Ventilation ◽  
Energy Savings ◽  
Pilot Project ◽  
Passive Cooling ◽  
Free Cooling ◽  
Air Conditioning Systems ◽  
Good Agreement

A significant portion of energy consumed in buildings is due to energy usage by heating, ventilation, and air conditioning systems. Free cooling is a good option for energy savings in the systems. In recent years, scientists, engineers, and architects designed successful and innovative buildings which use passive cooling techniques, such as natural ventilation. The house studied in the present work, is a pilot project undertaken jointly by the Centre for Development of Renewable Energies (CDER) and the National Centre for Studies and Research of the integrated building (CNERIB) in the framework of the MED-ENEC project (Mediterranean Energy Efficiency in Construction structure). The house under consideration has a surface area of 65 m2 and is located in the region of Algiers which characterized by a Mediterranean climate with relatively mild winters and a hot and humid summer. The aim of this work is to study the thermal comfort inside the house in summer without air conditioning systems, only ventilation is considered. The aim of this work is to study the effect of natural ventilation on both thermal and hygrometric comfort inside the house during the summer period. Numerical simulation is made using the TRNSYS software and the results obtained are in good agreement with measured values. The prototype home is designed in a way that natural ventilation allows thermal comfort which induced energy saving from air conditioning. The mean temperature measured in the interior of the house is 26?C. The relative humidity reaches about 70% in August. Thermal comfort is related to relative humidity that are the essential parameters of the feeling of comfort. Humidity is an important parameter in thermal comfort, it is why we can conclude that we have reached a relatively good hygrothermal comfort.

Applying the Passivhaus standard to a terraced house in a hot and humid tropical climate – Evaluation of comfort and energy performance

2020 ◽  
Vol 41 (3) ◽  
pp. 247-260
Author(s):  
Roy Candra Sigalingging ◽  
David Chow ◽  
Steve Sharples
Keyword(s):  
Relative Humidity ◽  
Thermal Comfort ◽  
Air Conditioning ◽  
Best Practice ◽  
Natural Ventilation ◽  
Tropical Climate ◽  
Energy Performance ◽  
Tropical Region ◽  
Humid Tropical Climate ◽  
Air Temperatures

In a hot and humid tropical climate, natural ventilation brings high levels of moisture into dwellings that, together with occupant activity, can result in very elevated internal relative humidity levels. Coupling these high relative humidities with high internal air temperatures creates occupant thermal discomfort, which is typically ameliorated in the tropics using energy-intensive air conditioning systems. This paper has investigated the potential benefits for thermal comfort and energy usage of applying the German Passivhaus standard to tropical dwellings. By creating a super insulated and air-tight envelope, the Passivhaus standard reduces fabric heat transfer, controls air infiltration and provides low-energy comfort. Applying this approach to a tropical terraced house might be effective but could, potentially, have an adverse impact on mechanical cooling demand. This study took an actual terraced property in Jakarta, Indonesia and thermally modelled its performance as insulation and airtightness levels were incrementally improved up to the Passivhaus standard. Field measurements in the dwelling of air temperature and relative humidity were used to validate the thermal model of the existing house. The validated model then tested the feasibility of meeting the Passivhaus energy standard for cooling in the modified tropical house. Simulation allowed the effects of air conditioning (AC) and dehumidifiers on thermal comfort and cooling loads to be investigated. The research develop the Passivhaus building model that had the floor insulation removed to let the ground floor act as a thermal sink and potentially provide radiant cooling. Analysis revealed that the building’s predicted air temperatures were affected in a beneficial way by having the Passivhaus without floor insulation. Practical application: Cooling in hot and humid tropical region is an energy-intensive approach. Design approaches that can bring comfort and save energy for the occupant are essential. The success of Passivhaus standard in mild climate might be transferable to bring comfort in tropical housing. Best practice can be developed by analysing the Passivhaus building performance in hot and humid tropical region.

scholarly journals Adaptive Thermal Comfort Potential in Mediterranean Office Buildings: A Case Study of Torre Sevilla

2018 ◽  
Vol 10 (9) ◽  
pp. 3091 ◽  
Author(s):  
Raúl Castaño-Rosa ◽  
Carlos Rodríguez-Jiménez ◽  
Carlos Rubio-Bellido
Keyword(s):  
Thermal Comfort ◽  
Air Conditioning ◽  
Natural Ventilation ◽  
High Tech ◽  
Adaptive Thermal Comfort ◽  
Adaptive Comfort ◽  
Conditioning Equipment ◽  
Air Conditioning Systems ◽  
The City

The design and construction of buildings is currently subject to a growing set of requirements concerning sustainability and energy efficiency. This paper shows a case study of the Torre Sevilla skyscraper, located in the city of Seville (in the south of Spain), which has high-tech energy-efficient features and which uses air-conditioning systems during most of its operating hours. The analysis carried out starts from a simulation in which occupants’ thermal comfort are obtained, based on the adaptive comfort model defined in the standard EN 15251:2007. With this approach, it is possible to determine the number of hours during operation in which the building has adequate comfort conditions only with the help of the envelope and natural ventilation. Consequently, the remaining useful hours require the use of air-conditioning systems. The results show that it is possible to improve the thermal performance of the building due to its location in the Mediterranean climate. To do this, advanced mixed mode (through manual-opening or mechanically-controlled opening windows) and active air-conditioning are suggested. This experimental proposal provides a reduction of the occupation hours which require the use of air-conditioning equipment by 28.57%, reducing the air-conditioning demand and, consequently, the energy consumption of the building.

Dehumidification Through Indirect Nighttime Ventilation

2001 ◽  
Author(s):  
Hussein Abaza ◽  
Yvan Beliveau ◽  
Jim Jones
Keyword(s):  
Relative Humidity ◽  
Natural Ventilation ◽  
Energy Savings ◽  
Passive Cooling ◽  
Cooling Load ◽  
Building Structure ◽  
Ventilation Strategy ◽  
Cooling Strategy ◽  
Simulation Results ◽  
Cool Night

Abstract Natural ventilation is an important passive cooling strategy. Using cool night air can cool the building structure and lower air conditions energy consumption. However, there are obstacles in using this cooling strategy, including high relative humidity, pollution, limitations in the thermal storage of the building, and low nighttime air temperature. This paper investigates energy savings by indirect ventilation to pre-cool buildings and reduces humidity. The nighttime ventilation strategy is based on optimizing the use of direct and indirect natural ventilation through an air-to-air heat exchanger. This strategy has been tested at the Beliveau House in Blacksburg, Virginia. Simulation results suggest that the indirect ventilation strategy at the Beliveau House reduces inside relative humidity on hot humid summer days by 20%, and the total summer cooling load by 38% when compared to the existing condition.

Evaluation of Thermal Comfort in an Air Conditioning Room Using a CFD Model

2011 ◽  
Vol 354-355 ◽  
pp. 717-721
Author(s):  
Fu Qiang Guo ◽  
Rui Bin Mei ◽  
Lei Zhang ◽  
Jun Wei Fan ◽  
Min Xue Li ◽  
...  
Keyword(s):  
Thermal Comfort ◽  
Work Environment ◽  
Air Conditioning ◽  
Theory And Practice ◽  
Cfd Model ◽  
Air Velocity ◽  
Airflow Velocity ◽  
Conditioning Room ◽  
Air Conditioning Systems ◽  
Good Agreement

In order to obtain the thermal comfort work environment, the distribution of temperature and airflow velocity in typical computer room of school building is discussed with different supply air angles and velocities of incidence by CFD model. The calculated temperature after cooling in the room has a good agreement with the measured value. Furthermore, the distribution of temperature and airflow is uniform and the environment is comfort for working with supply air angles and velocity of incidence 45° and 60° and supply air velocity of incidence 1m/s comparing with that of other parameters. Additionally, the change of temperature becomes slow down with the increment of time and the air-conditioning has less influence on the change of temperature after about 900s with supply air angle and velocity of incidence 45°and 1m/s, respectively. The research is of great significance both in theory and practice to design air conditioning systems and evaluate the thermal comfort conditions.

scholarly journals Multi-Circuit Air-Conditioning System Modelling for Temperature Control

2021 ◽  
Vol 83 (2) ◽  
pp. 14-24
Author(s):  
Ibrahim Oleolo ◽  
Hayati Abdullah ◽  
Maziah Mohamad ◽  
Mohammad Nazri Mohd Jaafar ◽  
Akmal Baharain ◽  
...  
Keyword(s):  
System Identification ◽  
Thermal Comfort ◽  
Air Conditioning ◽  
Energy Savings ◽  
Control Strategies ◽  
Model Development ◽  
Dynamic Modelling ◽  
System Modelling ◽  
Air Conditioning System ◽  
Air Conditioning Systems

The suitable application of innovative control strategies in Heating, Ventilation, and Air-conditioning systems is important to improving the energy efficiency and maintenance of temperature set point to improve thermal comfort in buildings. The increased focus on energy savings and appropriate thermal comfort has resulted in the necessity for more dynamic approach to the use of these controllers. However, the design of these controllers requires the use of an accurate dynamic modelling. Substantial progresses have been made in the past on model development to provide better control strategy to ensure energy savings without sacrificing thermal comfort and indoor air quality in the Heating, Ventilation, and Air-conditioning systems. However, there are scarce model using the data driven approach in the Multi-circuit air-conditioning system. This research, carried out a study on the choice of a dynamic model for an operating centralized multi-circuit water-cooled package unit air-conditioning system using a system identification procedure. Baseline data were collected and analyzed, the model development was achieved by processing, estimating and validating the data in system identification. Result shows that the Autoregressive-moving average with exogenous terms (ARMAX) of the third order model, established the best model structure with the highest Best Fit and Lowest Mean Square Error.

scholarly journals OPTIMIZATION APPLIED TO ENERGY EFFICIENCY AND THERMAL COMFORT OF BUILDINGS: BIBLIOMETRIC ANALYSIS ON TECHNIQUES AND APPLICATIONS

2018 ◽  
Vol 17 (2) ◽  
pp. 20
Author(s):  
C. F. da Silva ◽  
R. Z. Freire ◽  
N. Mendes
Keyword(s):  
Energy Consumption ◽  
Thermal Comfort ◽  
Bibliometric Analysis ◽  
Energy Demand ◽  
Air Conditioning ◽  
Energy Savings ◽  
Control Strategies ◽  
Building Projects ◽  
Air Conditioning Systems ◽  
And Control

The world's energy demand has raised concerns about supply difficulties, depletion of natural resources and environmental impacts such as destruction of ozone layer, global warming, climate change, among others. Recent studies indicate that energy consumption in buildings represents more than 40% of the world's energy consumption, with more than half of that attributed to air conditioning systems. Specific regulations and control strategies for heating, ventilation and air-conditioning (HVAC) systems should provide acceptable thermal comfort and reasonable indoor air quality. The evolution of researches in these areas can be evaluated by the organization of scientific production up to now. The objective of this study is to analyze quantitatively what was produced in terms of optimization associated to both energy savings and thermal comfort in buildings. This bibliometric analysis, based on Science Direct and IEEE Xplore databases, correlates common adopted terms to quantify how optimization, especially those associated to computational intelligence, are influencing building projects where thermal comfort and energy saving are taken into account. This research assumes a sample of 76 articles, and provided a statistical evaluation considering authors identification, and both articles and journals that were more cited by researchers in this area.

Effect of Air Conditioning Position on Thermal Comfort in the Floor Air Conditioning System

2014 ◽  
Vol 493 ◽  
pp. 74-79
Author(s):  
Y.A. Sabtalistia ◽  
S.N.N. Ekasiwi ◽  
B. Iskandriawan
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Energy Consumption ◽  
Thermal Comfort ◽  
Energy Efficient ◽  
Air Conditioning ◽  
Air Conditioning System ◽  
Air Supply ◽  
Air Conditioning Systems ◽  
Air Diffusion

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.

scholarly journals Thermal adaptive behavior and thermal comfort for occupants in multi-person offices with air-conditioning systems

2021 ◽  
pp. 108432
Author(s):  
Peiping Zheng ◽  
Chunxiao Wang ◽  
Yanchen Liu ◽  
Borong Lin ◽  
Huijun Wu ◽  
...  
Keyword(s):  
Thermal Comfort ◽  
Adaptive Behavior ◽  
Air Conditioning ◽  
Air Conditioning Systems

scholarly journals Thermal comfort control via air conditioning system using fuzzy neural network feedback controller

2020 ◽  
Vol 19 (2) ◽  
pp. 586
Author(s):  
Somaye A. Mohamadi ◽  
Abdulraheem J. Ahmed
Keyword(s):  
Neural Network ◽  
Thermal Comfort ◽  
Environmental Conditions ◽  
Air Conditioning ◽  
Fuzzy Controller ◽  
Environmental Parameters ◽  
Thermal Conditions ◽  
Real Time Control ◽  
Air Conditioning System ◽  
Air Conditioning Systems

<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>

scholarly journals THERMAL COMFORT AND ENERGY SOLUTIONS FOR A BETTER RESIDENTIAL ENVIRONMENT IN MALAYSIA

2015 ◽  
Vol 13 (5) ◽  
Author(s):  
Noor Aziah Mohd Ariffin
Keyword(s):  
Thermal Comfort ◽  
Air Conditioning ◽  
Energy Savings ◽  
Energy Performance ◽  
Data Monitoring ◽  
Medium Density ◽  
Design Strategies ◽  
Residential Energy ◽  
Passive Design ◽  
Design Systems

In hot-humid Malaysia, there are around five million units of housing. Among these, the medium-density terraced are the most built. However, little emphasis was given to designing for thermal comfort and energy efficiency. Consequently, air-conditioning is ubiquitous with ever-rising residential energy consumption. This paper studied passive design systems to improve living conditions and conserve energy through orientation and insulation parameters for terraced housing. Utilizing a triangulation of methods to correlate between thermal comfort and energy performance, findings from the questionnaire survey, data monitoring and computer simulation contended that with the passive design strategies minimum thermal comfort is attainable and energy savings predicted.

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