Indoor Comfort Parameters Research Articles

Comparative Assessment of Indoor Air Quality and Comfort Parameters in Government and Non-Government Hospitals in Southwestern Bangladesh

Indoor air quality (IAQ) is considered crucial in the hospital environment for the health improvement of the patients and the well-being of all the staff and visitors. Despite that, in a lot of hospitals in developing and underdeveloped countries, IAQ is severely impaired by different factors. The lower-income people are mostly dependent on the government-subsidized public hospital, and that necessarily creates a huge number of patients and gatherings and results in impaired IAQ. In this study, nine hospital wards were selected from one public and one private hospital in the southwestern part of Bangladesh to compare the IAQ with respect to the outdoor values. Five IAQ parameters (PM2.5, PM10, VOC, CO2, and HCHO) and three indoor comfort parameters (temperature, relative humidity, and noise) were assessed at three different times of the day (morning, midday, and after noon). The results suggested that PM2.5, PM10, and CO2 were significantly higher in the private hospital units (48.59±12.34µg/m3, 65.27±14.18µg/m3, and 721.13±159.20ppm, respectively) than the public hospital units. In contrast, temperature and relative humidity were found to be slightly lower in the private hospital units (RH: 81.80±1.29%, T: 31.27±1.24°C) than in the public hospital units. The detected noise level was significantly higher in each hospital's indoor units than the outdoor units. The I/O ratio suggests most contamination sources are indoors for the private hospital units, while the toxicity potential found considerable health implications for those indoor locations.

The Effect of European Climate Change on Indoor Thermal Comfort and Overheating in a Public Building Designed with a Passive Approach

Dynamic building energy performance modeling is becoming increasingly important in the architectural, engineering, and construction (AEC) industry because of the sector’s significant environmental impact. For such analysis, a climate file representing a typical meteorological year (TMY) is needed, including hourly values for the most important weather-related parameters. However, TMY shows little resemblance to the future of the particular location where a building has been used for decades. Therefore, using predicted future climates during building design is unfortunately rarely practiced, potentially undermining the strategies that should be the fundamental basis of the design. To explore this question, our study compared the heating and cooling energy consumption, indoor thermal comfort, and summer overheating potential of a selected building for three distinctive European climates, in Hungary, Portugal, and Lithuania. All of them were changed according to the IPCC RCP4.5 scenario, and were examined for the present, the 2050, and the 2100 scenarios. We also tested adaptive clothing to evaluate the indoor comfort parameters. The results show a 10% increase in heating and cooling energy use for the same construction and location between 2020 and 2100. The continental climate of Budapest is the most threatened by summer overheating, with an increase of 69% for the ODH26 indicator. A more balanced warming for Lisbon was found (23%), and moderate changes for the city of Kaunas (a 153% increase from a very low baseline).

Accurate thermal prediction model for building-integrated photovoltaics systems using guided artificial intelligence algorithms

Progress in development of building-integrated photovoltaic systems is still hindered by the complexity of the physics and materials properties of the photovoltaic (PV) modules and its effect on the thermal behavior of the building. This affects not only the energy generation, as its active function and linked to economic feasibility, but also the thermal insulation of the building as part of the structure’s skin. Traditional modeling methods currently presents limitations, including the fact that they do not account for material thermal inertia and that the proposed semi-empirical coefficients do not define all types of technologies, mounting configuration, or climatic conditions. This article presents an artificial intelligence-based approach for predicting the temperature of a poly-crystalline silicon PV module based on local outdoor weather conditions (ambient temperature, solar irradiation, relative outdoor humidity and wind speed) and indoor comfort parameters (indoor temperature and indoor relative humidity) as inputs. A combination of two algorithms (Grammatical Evolution and Differential Evolution) guides to the creation of a customized expression based on the Sandia model. Different data-sets for a fully integrated PV system were tested to demonstrate its performance on three different types of days: sunny, cloudy and diffuse, showing relative errors of less than 4% in all cases and including night time. In comparison to Sandia model, this method reduces the error by up to 11% in conditions of variability of sky over short time intervals (cloudy days).

Improvement of Daylight Factor Model for Window Size Optimization and Energy Efficient Building Envelope Designs

Based on a new approach for the prediction of the Daylight Factor (DF), using existing empirical models, this research work presents an optimization of window size and daylight provided by the glazed apertures component for a building located in a hot and dry climate. The new approach aims to improve the DF model, considering new parameters for daylight prediction such as the orientation, sky conditions, daytime, and the geographic location of the building to fill in all the missing points that the standard DF, defined for an overcast sky, presents. The enhanced DF model is considered for the optimization of window size based on Non dominated Sorting Genetic Algorithm (NSGA II), for heating and cooling season, taking into account the impact of glazing type, space reflectance and artificial lighting installation. Results of heating and cooling demand are compared to a recommended building model for hot and dry climate with 10% Window to Wall Ratio (WWR) for single glazing. The optimal building model is then validated using a dynamic convective heat transfer simulation. As a result, a reduction of 48% in energy demand and 21.5% in CO2 emissions can be achieved. The present approach provides architects and engineers with a more accurate daylight prediction model considering the effect of several parameters simultaneously. The new proposed approach, via the improved DF model, gives an optimal solution for window design to minimize building energy demand while improving the indoor comfort parameters.

Experimental Studies on TVOC Concentrations and their Relationships with Indoor Comfort Parameters

Indoor air quality (IAQ) remains a very important issue because it can significantly affect people’s health, comfort and productivity. Volatile organic compounds (VOCs) comprise an important group of chemicals that are commonly present in indoor air. They are related to the sick building syndrome (SBS) and exposure to VOCs is of considerable concern due to their potential chronic and acute health outcomes which includes eye irritation, nose and throat discomfort, headache, allergic skin reaction, nausea, fatigue, or dizziness. Most of the times the effects of VOCs on human health are amplified by indoor conditions such as temperature and humidity. The paper presents the findings of the analysis of the relationship between total volatile organic compounds (TVOC) concentrations and their influencing factors like indoor comfort parameters (temperature and relative humidity) and the type of indoor spaces (offices, residential and educational). Keywords: TVOC concentrations, indoor comfort parameters, Pearson correlation coefficients

REAL TIME MONITORING OF INDOOR ENVIRONMENT QUALITY AND ENERGY CONSUMPTION IN A RESIDENTIAL BUILDING

Several theoretical studies were oriented towards the relationship between the main two building design estimators (building energy consumption and indoor environmental quality) but very little experimental research has been carried out in order to underline the correlation between this two parameters. This paper is focused towards the experimental study of the correlation between these two design estimators. Several indoor comfort parameters (air temperature, radiant mean temperature, sound pressure level, outdoor ventilation rate and lighting level) as well as energy consumption were monitored in different rooms inside a laboratory experimental house at real scale located in Bucharest, Romania. Time variations of these parameters and space distribution maps inside the house were analysed in order to understand the indoor comfort variations. Four comfort indexes (thermal comfort index, acoustic comfort index, indoor air quality index and visual comfort index) were determined and their time variations were used to emphasize the correlation between the indoor environment quality and the energy consumption. The overall indoor environment quality was found to be inversely correlated with the energy consumption and that this general trend can be easily influenced by the weight of the four comfort types.

Parametric analysis on the thermal comfort of a cooling tower based thermally activated building system in tropical climate – An experimental study

Thermally Activated Building System (TABS) provides not only better thermal comfort but also good indoor air quality. It can be coupled with passive cooling systems as it can operate at a relatively higher water temperature. Even though TABS is a promising energy-efficient and eco-friendly system, the influences of various design and operating parameters on the indoor thermal comfort of a building with TABS are not well understood. Hence, the influences of cooling surfaces (area), shading, natural ventilation and ceiling fan on the performance of cooling tower based TABS were investigated in an experimental room of dimensions 3.5 m × 3.5 m × 3.15 m. The increase in the number of cooling surfaces decreased (favourable) the thermal comfort indices and advanced the time at which their maximum and minimum were reached. The average predicted percentage of dissatisfied was 89% if roof alone was cooling. This reduced to 20% if all the surfaces of the building were cooled. Shading of the roof reduced the maximum operating temperature of the indoor space by 0.9 °C when all the surfaces of the building were cooled with TABS. The use of ceiling fan increased the indoor operative temperature marginally. However, the increase was less than the neutral temperature offset of 2.6 °C that was achieved by higher air movement. Thus, the use of the fan results in a better indoor thermal comfort. Natural ventilation advanced the occurrence of the maximum temperature of indoor air by 1½ and 2¾ hours for fan off and fan on cases respectively. It also advanced the extrema of the other indoor comfort parameters. The cooling tower based TABS was able to achieve thermal comfort even in unfavourable warm and humid tropical climates under certain operating conditions.

Proposal for a small two-story living room house based on air-quality monitoring

The evolution and innovation in construction is based on extensive testing and validation, best performed on existing buildings, in order to assess their behavior in time. Occupants health and comfort issues are fundamental concerns of the society, which together with economy and environment make up the “sustainability triangle”. This becomes even more significant in the case of dwellings with reduced floor areas and built in high-density urban areas. The paper focuses on monitoring air quality parameters in an existing two-story living room house and proposes an architectural solution for improving comfort conditions. The 48 square meters house is a sustainable design, with low-embodied energy, high thermal performance and open-floor flexibility. In order to highlight the benefits of this open-space house, the study was focused on the comparison of two types of dwellings - a two - bedroom apartment with conventional subdivision and a one - bedroom house with double-height living room. In both cases the same indoor comfort parameters were measured: CO2 levels, humidity and temperature. The study is structured in two stages: the monitoring of the interior air quality of a two-story living room and the proposal of a similar house typology with improved comfort parameters. By analysing the complex monitoring data, the new architectural proposal keeps the environmental qualities of the existing house, with improved comfort benefits.

CFD Heat Transfer Analysis for Heat Pipes Integration into Buildings with Glazed Façades

This study presents a CFD Heat Transfer Analysis for Heat Pipes integration into Buildings with Glazed Façades. This consists into the introduction of heat pipes in the building envelope structure for taking over the heat from glazed façade cavity and transmission, respectively accumulating in the wall structure for achieving the indoor comfort parameters in winter and transitional seasons (autumn and springtime).

Use of TDR to Compare Rising Damp in Three Tuff Walls Made with Different Mortars

AbstractCapillary rise is a serious phenomenon that may have potentially devastating consequences within buildings (biological corrosion, worsening of indoor comfort parameters, worsening of therma...

Summer operative temperatures in free running existing buildings with high glazed ratio of the facades

Nowadays, low energy and low exergy solutions are widely used for new buildings, but existing buildings have high energy demand because of poor thermal properties of their envelope. The situation is worse in summer period in case of buildings built before 1970 with large transparent areas on the facades. The high summer outdoor temperatures and the increased number of heat waves can lead to extremely hot indoor environments or extremely high cooling energy use in these buildings. In this paper indoor operative temperatures and PMV were calculated in east and west oriented offices using measured meteorological parameters and the methodology given by EN ISO 13790. Furthermore, indoor comfort parameters were measured using TESTO 480 instrument. The operative temperature was calculated based on the measured air and globe temperatures in different locations of a room. The effect of lace curtains and drapes on the operative temperatures was analysed.

Children's exposure to indoor air in urban nurseries-part I: CO2 and comfort assessment

Indoor air quality (IAQ) in nurseries is an emerging case-study. Thus, this study, as the Part I of the larger study “Children's exposure to indoor air in urban nurseries”, aimed to: i) evaluate nurseries’ indoor concentrations of carbon dioxide (CO2), a global IAQ indicator, in class and lunch rooms; ii) assess indoor comfort parameters–temperature (T) and relative humidity (RH); and iii) analyse them according to guidelines and references for IAQ, comfort and children's health. Indoor continuous measurements were performed. Non-compliances with guidelines were found in comfort parameters, which could cause discomfort situations and also microbial proliferation. Exceedances in CO2 concentrations were also found and they were caused by poor ventilation and high classroom occupation. More efficient ventilation and control of comfort parameters, as well as to reduce occupation by reviewing Portuguese legislation on that matter, would certainly improve IAQ and comfort in nurseries and consequently safeguard children's health.

Simulation of Thermal Comfort Conditions of an Air-Conditioned Cafeteria in the Tropics

This paper studies the current thermal comfort condition of an air-conditioned cafeteria based on objective measurements and computational fluid dynamics (CFD) modeling. Indoor comfort parameters such as temperature and airflow rate were simulated by a CFD tool. The results from field measurements and predicted values were then compared and contrasted. A simulated model that has the same geometrical configuration as the cafeteria was set as a benchmark model. Several additional models with different configuration of cafeteria layouts were proposed to achieve the required air temperature. It was found that the predicted results from the proposed models showed even distributions of airflow characteristics and temperature gradients. To maintain a thermally-acceptable air temperature of 28 °C, it is proposed that an additional air-conditioning unit be retrofitted to the current cafeteria layout.

Design configuration for a higher efficiency air conditioning system in large space building

The full air conditioning and the stratified air conditioning designs in large space buildings were investigated based on air flow measurement that pertains to an in-patient hall of a hospital building. We compared and analyzed the indoor comfort parameters such as temperature and air velocity. On the basis of the measurements, we calculated the theoretical load index by solving the model for inner surface temperature of the building envelope based on the modified radiant heat transfer method. Using flow fields and parameters that are generated by computational fluid dynamics (CFD), the indoor thermal comfort when adopting the full air conditioning and the stratified air conditioning designs can be effectively analyzed. And the respective energy saving rate of the two air conditioning design loads in the hall at different storey heights, window-wall ratios, and air supply heights can be compared. Finally, the recommendation for usage of the stratified air conditioning design was put forward in large space buildings.

Thermal comfort study of an air-conditioned lecture theatre in the tropics

This paper evaluates the current thermal comfort conditions of an air-conditioned lecture theatre in a tertiary institution using objective measurement, computational fluid dynamics (CFD) modelling and subjective assessment. A CFD tool was used to simulate the indoor comfort parameters, such as temperature, airflow rate and relative humidity. Corroboration between results from the field measurements and predicted values was conducted. It was found that the measured air temperatures, air velocities and relative humidities were within the limits of thermal comfort standards, although temperature and relative humidity were located at the extreme of the limits. The predicted results showed good distributions of airflow characteristics and temperature gradients, and these were in fair agreement with empirical measurements. The overall comfort vote, predicted mean vote and predicted percentage dissatisfied indices found the occupants to be slightly uncomfortable and dissatisfied. Additionally, recommendations were made to improve the thermal comfort condition and reduce the build-up of concentration of carbon dioxide in the lecture theatre.