bluuebunny/crossref_metadata_2025 huggingface dataset:
Experimental characterization of the impact of unsteady airflows on tracer gas measurement
Authors: Remion Gabriel , Moujalled Bassam , El Mankibi Mohamed
Published: October 2019

Natural ventilation induces several issues when trying to measure airflows. Low pressure differences that drive natural airflows are very sensitive. A small pressure drop introduced by an airflow-meter would significantly affect the flow pattern. Furthermore, for window aired buildings or rooms, the implementation of a protocol to characterize the flow through a window is practically hard to implement and often poorly reliable. For these reasons, tracer gas methods are widely used to measure natural airflows. They do not interfere with the flow path, as they do not require any other instruments than concentration sensors. The principle is to inject a tracer gas inside a chamber and to observe the evolution of the concentration of the tracer gas. The knowledge of the emission rate of the gas, as well as its concentration evolution allows describing the airflow.

Unfortunately, tracer gas methods are highly sensitive to the measurement noise, which is likely to be significant for concentration sensors. Most used methods, in the literature, use regression techniques to reduce the measurement noise. However, the regression implies steady airflows during the measurement, which should theoretically discard natural airflows. For lack of better methods, these techniques are often used in natural conditions, regardless of the variation of airflows. The present paper experimentally assess the impact of variable airflows on the accuracy of most common tracer gas methods, namely the constant injection and the concentration decay methods. The experiment was implemented in a laboratory cell, taking advantage of a controllable extract fan to simulate natural airflows, while allowing the direct measurement of the airflow in the extract duct. This value provides the reference value for the comparison of tracer gas methods results. Insights are also given, using signal-processing techniques to improve the reliability of tracer gas methods under variable airflows.
Passive ventilative cooling in residential buildings: a review
Authors: Song Ge , Ai Zhengtao , Zhang Guoqiang
Published: October 2019

The energy-saving potential of passive ventilative cooling has been underestimated, and the abuse of mechanical ventilation has resulted in significant energy waste in air quality. The use of large temperature difference between day and night; large temperature difference between indoor and outdoor during the transitional season; surface cold storage can greatly enhance the cooling effect of passive ventilation, reduce energy consumption and improve indoor air quality (IAQ). This paper analyzes and summarizes the research process of techniques and methods for realizing passive ventilation and cooling in residential buildings by using large temperature difference and accumulation of cold. The research results of the literature are mainly divided into two categories. On the one hand, the research methods and application characteristics of natural ventilation passive cooling technology formed by large temperature difference, which is dependent on climatic factors and residential conditions are described. On the other hand, the application environment and research technology of energy storage such as tunnel wind, which is based on the ventilation strategy and installation were described. Most of the research results show that the tunnel wind is relatively stable and comfortable, but the construction cost is too high, and the temperature difference is used to depend on the building category and climate environment. Passive ventilative cooling studies with focus on residential buildings are presented including both challenges and potential for improving building energy performance.
Including EAHX (earth-to-air heat exchanger) in early-design phases considering local bioclimatic potential and specific technological requirements
Authors: Chiesa Giacomo
Published: October 2019

Horizontal ground systems for ventilative cooling/heating, such as earth-to-air heat exchangers (EAHX), are a valid pre-heating and pre-cooling low-energy techniques to reduce the building energy consumptions for space heating and cooling. Nevertheless, the potential of these systems, such as others passive solutions, is local specific and need for devoted design methodologies. In particular, EAHXs need to be included in the design process as soon as possible in order to maximise the potentiality and allow for their integration – operational, technological and environmental issues. The paper will introduce a design methodology to define the local climatic potential of EAHX since the building programming phase by defining specific boundary conditions in well-known bioclimatic chart instruments. The effect of different design choices will be analysed for a set of three representative Italian locations. Furthermore, main functional, operational and environmental requirements will be discussed for this technical system. This analysis is based on the performance-drive approach to environmental and technological design – see for example UNI 8290-2:1983 – and is hence compatible with the technological-design practice and early-design consolidated methodologies.
Considerations for providing healthy, comfortable, energy-efficient whole-house mechanical ventilation during humid weather in near zero energy homes
Authors: Withers Charles
Published: October 2019

Whole-house mechanical ventilation (WHMV) is necessary for adequate ventilation in healthy near zero energy homes in most cases. Ventilation standards such as ASHRAE 62.2-2016 call for more ventilation than can be provided by natural ventilation in new homes built better than minimal building code requirements. A very troubling matter is that different studies in different climate locations have shown that a majority of WHMV evaluated in occupied homes has found them to be turned off, broken, or delivering too little ventilation when operational. Some homes with adequate ventilation may have increased potential for comfort complaints, moisture control issues, and even higher than expected energy usage. Higher energy usage will occur when supplemental dehumidification is needed. Balanced ventilation provided through a heat recovery ventilator or an energy recovery ventilator may be a good approach for many climate zones, however supplemental dehumidification needed for homes intended to maintain relative humidity around 50% during mild humid weather. Recent studies found that the highest efficiency variable air conditioning systems do not dehumidify as well as lower efficiency single stage systems, but some may be capable of very good dehumidification negating the need for costly supplemental dehumidification. This paper will use recent lab and field research studies to discuss details of issues that engineers and builders must consider to design WHMV with good potential of providing healthy, comfortable and energy-efficient ventilation.
Estimation and analysis of ventilation rates in schools in Indian context: IAQ and Indoor Environmental Quality
Authors: Jayakumar Sandhiya , Apte Michael G
Published: October 2019

The prolonged exposure to indoor air pollution may affect the health, comfort and performance of the occupants. Failing to address Indoor Air Quality (IAQ) problems may lead to short-term and long-term health problems. The health effects may vary for different individuals depending on factors like age and medical conditions, children being young and sensitive to the environment, are more susceptible to the same. The primary focus of this research is to estimate the ventilation rates in schools in Ahmedabad by using carbon dioxide (CO2) exhaled by the occupants, using steady state mass balance method. The air flow in the naturally ventilated classrooms was between 61.5 l/s per person to 15.6 l/s per person. The air flow in air-conditioned classrooms was 0.9 l/s per person and 1.0 l/s per person. The air flow in naturally ventilated classrooms are excessively high, more than meeting prescribed rates, while air flow in air-conditioned classrooms is far below the prescribed outdoor air rate per person as provided in ASHRAE 62.1: 2016 [1] and in the Bureau of Indian Standards [2].
Numerical modelling and experimental validation of pcm-to-air heat exchangers: application of ventilated building envelopes
Authors: Dardir Mohamed , El-Mankibi Mohamed , Haghighat Fariborz
Published: October 2019

The earlier applications of phase change material (PCM)-to-Air heat exchangers (PAHXs) reported the insufficient cooling charging energy due to system storage abilities, the profile of inlet air temperature, and the charging duration. This paper proposes a developed PAHX system for building envelope applications utilizing both convective and long-wave radiative heat transfer components. A 2D numerical model was proposed utilizing an apparent heat capacity method to represent the PCM latent thermal storage developing both convective and radiative thermal boundaries. The radiative component was developed to study the effect of the system exposure to the night-time sky during the PCM solidification period. The convective component was comprehensively developed mainly between the storage medium (PCM) and the air channel. A real-scale prototype was constructed for the whole model experimental validation. Field experiments were designed and conducted in the warm temperate climate of Lyon, France during summer. The validation criteria were proposed based on ASHRAE guideline 14. The results of the comparison between simulated data and experimentally obtained data showed that the system temperature was within the accepted range of the proposed criteria.
Ventilative cooling potential of buildings in Australia
Authors: Tartarini F , Fiorentini M , Ledo Gomis L , Cooper P
Published: October 2019

The demand for space cooling is the fastest growing end-use of electricity in buildings since many rely on the use of air-conditioners only to control the indoor climate. Ventilative cooling is a passive cooling technique, which involves the use of outdoor air to lower buildings’ indoor air temperature. In order to determine whether ventilative cooling may have the ability to reduce cooling loads, a detailed analysis of the local climate is needed. The aim of this study was to identify which Australian geographical regions have a suitable climate for the utilization of ventilative cooling techniques. The assessment of climatic potential for each geographic location was carried using two approaches: (i) a methodology which does not require detailed knowledge of the building characteristics, and; (ii) building performance simulation of a ‘typical’ Australian detached home. Results showed that the most populated Australian cities would benefit from the use of ventilative cooling techniques whereas the northern coastal region does not have a suitable climate.
Improving the Energy Performance Certificate recommendations’ accuracy for residential building through simple measurements of key inputs
Authors: Gonzalez-Caceres A , Arvid Vik T , Granheim P , fælth J P , Berg L
Published: October 2019

The Energy Performance Certificate (EPC) allows building users to be informed and aware of the quality of the buildings in terms of energy needs. Additionally, the EPC includes a future for existing buildings, which is the incorporation of a Recommendation list of Measures (RLMs) to improve their energy performance in a cost-effective way. Which have risen the question if this tool can provide trustful Cost-effective recommendations due despite the uses of standardized inputs. This study focuses on estimating the impact of using measure ventilation rate, heating set point and airtightness on the profitability of the recommendations. The study is based on common dwelling in Norway, comparing results obtained with a Building Performance Simulation Software, following the Norwegian standard for energy certification and with the uses of measured ventilation rate, airtightness and real heating set points. The results show that the performance gap can be reduced significantly just by adopting these inputs, increasing the confidence on the RLMs and reducing the uncertainty of the investment.
Key findings of IEA EBC Annex 68 - indoor air quality design and control in low energy residential buildings
Authors: Rode C , Abadie M , Qin M , Grunewald J , Kolarik J , Laverge J
Published: October 2019

The overall objective of the “Annex 68” Project, which belongs to the International Energy Agency’s “Energy in Buildings and Communities” Implementing Agreement, has been to develop the fundamental basis for optimal design and control strategies for good Indoor Air Quality (IAQ) in highly energy efficient residential buildings, and to disseminate this information in a practically applicable guide. The strategies shall facilitate the possibility to design and operate residential buildings with minimal energy use, while ensuring impeccable indoor climates.

The project completes its working phase by the end of spring 2019. The work has gathered laboratory and field data and developed new knowledge on pollution sources in buildings and how the transport mechanisms for the pollutants interact with heat, air and moisture conditions in materials and indoor zones. Furthermore, the project has assembled a set of contemporary models to simulate the combined heat, air, moisture and pollution conditions of buildings and their assemblies. The purpose has been to identify and describe amenable ways to optimize the provision of ventilation and air-conditioning. The paper gives an account of the project highlights.
A smoke exhausting method through a baffle-coupled shaft during tunnel fires
Authors: QianKun Hou , Weng Miao-cheng , liu Fang
Published: October 2019

In natural ventilation of road tunnel shaft, the plug-holing and boundary layer separation will decrease the efficiency. A new concept (baffle-coupled shaft) is put in place to solve the difficulty. Install baffle on both sides of the shaft (when the fire occurs upstream of the shaft, the baffle upstream of the shaft closes and the baffle downstream of the shaft opens), in the early stage of the fire, it can function as a smoke barrier. Numerical simulation was performed using the Fire Dynamic Simulation (Version 5.5.3). We use the mass flow of carbon monoxide discharged through the shaft as a basis for evaluating the efficiency of exhausting smoke. We could have determined that with the height of the baffle increasing, so does the efficiency of exhaust. In the investigation, the height of urban road tunnels is generally about 5 meters. So, it is appropriate to set the baffle height to 2m. Comprehensive car capacity, economy and cold air distributed, we can get a better He, that is in 1.0-1.5.
Influence of building airtightness on the internal thermal comfort and air quality in the single family house
Authors: Kisilewicz T , Nowak-Dzieszko K , Rojewska-Warchał M
Published: October 2019

The knowledge of the air exchange and building air-tightness is an indispensable source of information, both on the design and operation stage of the building use. Properly functioning ventilation system affects significantly internal thermal comfort and internal air quality. Infiltration of air determines the proper functioning of the gravitational ventilation, still the most commonly used system in Polish single-family housing. However, the most popular and easy to measure parameter: building airtightness (n50), does not specify the real air exchange in the actual climatic conditions. The real air flow rate may be determined with much more troublesome gas tracing method. Air flow rate, n, is in this method obtained from the decaying curve of gas concentration after injection of tracer gas into the building. This paper presents the results of the airtightness measurements conducted in a single family house with natural ventilation. Both, n
50 parameter and building air flow rate n have been measured. The results of the measurements were used as a model calibration tool in the annual computational simulations carried out in the Design Builder program for the Polish climatic conditions. Based on these simulations the authors determined the influence of building airtightness on the internal thermal comfort and the potential scenario of its control.
The effects of temperature and humidity on the VOC emission rate from dry building materials
Authors: Zhou Shan , Liu Hong , Ding Yong , Wu Yuxin
Published: October 2019

With the development of the economy and society, a wide variety of new building decoration and materials are widely used indoors. The concentration of pollutants such as formaldehyde, volatile organic compounds, benzene and ammonia in indoor air witnessed increase, causing increasingly serious indoor air pollution problems. Indoor building decoration materials are one of the main sources of indoor VOCs. In this paper, the emission law of VOCs in dry building materials with environmental conditions is studied. The environmental test cabin is used to test the formaldehyde and TVOC concentration released. The single factor variable method is used to study how different environmental conditions (temperature and relative humidity) affect the rate of formaldehyde and TVOC released from dry building materials. According to the results, increase of ambient temperature and relative humidity will promote the release of TVOC, which will affect its peak concentration and stable concentration, and the effect on formaldehyde release is more significant. This study clarified the release law of VOCs in artificial boards under different environmental conditions, which is of great significance for reducing indoor air pollutant levels and improving indoor air quality.
Comparative inhalation exposure/toxicology analysis of e-cigarette vapors with different puffing behaviors using PBPK-CSP-CFD approach
Authors: Kuga Kazuki , Ito Kazuhide
Published: October 2019

The overarching purpose of this study is to develop a numerical prediction method for assessment of human health risks caused from the inhalation exposure of various contaminants generated by electronic cigarettes (e-cigarettes). In this study, the inhalation exposure to contaminants, generated from e-cigarette smoking under two types of puffing behaviours was quantitatively estimated adapting a coupled physiologically based pharmacokinetic (PBPK)–computational fluid dynamics (CFD) model to a numerical respiratory tract model. Heterogeneous contaminants concentration distributions inside the respiratory tract were predicted through transient CFD simulations. For evaluating adsorption flux onto respiratory tissue surface, tissue surface contaminants concentrations of respiratory tract were calculated by using two concepts: partition coefficient between air-phase and tissue-phase and analogy of flux conservation. Contaminants concentration distributions inside the tissue were analyzed by using PBPK model. Through the coupled PBPK-CFD analyses, we indicated total fractions of contaminants inhaled from e-cigarette: (i) adsorbed onto tissue surface of respiratory tract, (ii) transported to deeper bronchial regions, and (iii) released into the indoor environment by exhalation. Basically, we indicated total respiratory uptake as a health risk factor of e-cigarette user and total amount of chemicals released into the indoor environment by exhalation as data which enable us to analyze second-hand and third-hand effects against non-user and indoor air quality.
Formaldehyde monitoring in office buildings located in tropical climates of India
Authors: Kiran Kumar D E V S , Jyothi Latha T , Suresh R , Arunvel T
Published: October 2019

Indoor air pollution is a result of complex phenomenon that occurs due to constantly changing interaction of various indoor and outdoor environmental factors. Volatile Organic Compounds (VOCs) are the major pollutants in air conditioned indoors, perhaps having a large subset of hazardous compounds. In this study, formaldehyde (HCHO) was monitored at 30 minute interval using portable photoelectric absorptiometric sensors along with comfort parameters like air temperature, relative humidity and air flow rate at six newly constructed or renovated office buildings located in composite, temperate and warm-humid climatic zones (in various parts of India). Results show that formaldehyde emissions exceeded the limits suggested by LEED guidelines (27 ppb) in all the buildings except in the ones where low emitting green interiors were used. Furniture and interior decorative work were found to be the primary sources of formaldehyde emission than other parameters. A logarithmic relationship (R2=0.65) was established between HCHO and respective age of the building/refurbished time. The analysis also presents that in a scenario of green interiors (low HCHO concentration) and the humidity levels above 60%, the trend of HCHO concentration with indoor moisture exhibits certain time delays in reaching equilibrium due to slow conditioning of HCHO molecules and indoor moisture. The study provides a rational analysis on HCHO emissions in Indian office buildings, which is important to understand possible sources and their effects on HCHO concentration in office indoors. The study data helps to implement required measures to control indoor humidity levels or necessary HCHO mitigation strategies during design and operation process of the air-conditioned office buildings.
The heat gain-based generation method of coincident weather data for walls with a large thermal lag
Authors: Fang Zhengcheng , Chen Youming , Wu Shihai
Published: October 2019

The coincident weather data (CWD) means the combination of weather data that affect a moment of indoor heat gains at the same time. It includes the coincidence of dry-bulb temperature, wet-bulb temperature and solar irradiation. The selection of design solar irradiation in the current ASHRAE and CIBSE design handbooks is independent on design dry-bulb and wet-bulb temperature. And the generation methods of CWD in those are based on the original weather data itself. Furthermore, the generation methods in some related literatures are either ignoring the thermal delay and decay of building envelope or not appropriate for engineering using. Hence, a new method based on the hourly heat gain formula, three weather parameters, building heat characteristics and risk factor was developed for the generation of coincident solar irradiance, dry-bulb and wet-bulb temperature. The method was applied to historic weather records of 25 years in Hong Kong and data of 302 kinds of walls to generate coincident design weather data. The result shows that the design dry and wet bulb temperature can be lowered and the solar radiation values are more regular, compared to traditional weather data. In a category of walls, the deviation between the representative parameter and CWD is less than 5%. It’s means that using the new CWD can reduce the building energy consumption, and engineering heat gain calculations can be more precise and concise.
A physiological chamber experiment to explore human thermal adaption on the seasonal scale
Authors: Ji Wenjie , Cao Bin , Zhu Yingxin
Published: October 2019

In the theory of thermal adaption, it’s usually believed that people can adapt to the thermal environment actively from three aspects: physiology, psychology and behaviour. The purpose of this study is to explore whether there is some thermal physiological adaption on the seasonal scale. A chamber experiment was designed and conducted twice at spring and early summer with the time interval of 1 month. There were totally four experimental conditions in each experiment, including 16 °C, 22 °C, 28 °C and 34 °C. We measured four physiological parameters of 18 recruited subjects, including in skin temperature, blood flow, moisture evaporation amount and metabolic rate. At the same time, some of the subjective thermal evaluation was collected. It was a tracing experiment in which the same individual was asked to participate in the experiment twice. So, some comparison on physiological parameters and thermal comfort evaluations at different season could be explored to illustrate the characteristics of thermal adaption. We found that there was some obvious difference on the moisture evaporation and the blood flow after one-month adaption, and the thermal comfort vote in the same temperature also had some variation. This study is meaningful for further understanding the mechanism of thermal adaption.
A simulation study on correlation between indoor volatile organic compounds and carbon dioxide concentration in Beijing, China
Authors: Liang Weihui
Published: October 2019

Indoor air quality (IAQ) plays a significant role to human health. There are many pollutants have been identified indoors. Volatile organic compounds (VOC) are one of the most ubiquitous pollutants with proved adverse health effects. Carbon dioxide (CO2) has a long history of being used as an indicator for IAQ. The VOC sensors are generally expensive and their accuracy are not as good as CO2 sensors. Whether CO2 could be a good indicator for VOC is important to determine ventilation control strategy in engineering application. In this study, indoor CO2 and formaldehyde concentrations in a Beijing’s bedroom was simulated for a whole year by the Monte Carlo method. When emission rate of CO2 was constant, strong positive correlation was identified between CO2 and formaldehyde. CO2 could be a good indicator for formaldehyde when emission rate of formaldehyde (mg/h) divided by the emission rate of CO2 (L/h) was smaller than 0.14. When emission rate of CO2 was changing, CO2 could not be used as an indicator for formaldehyde in general.
Impacts of energy retrofits on indoor CO2 concentration and air change rate
Authors: Leivo Virpi , Prasauskas Tadas , Aaltonen Anu , Martuzevicius Dainius , Haverinen-Shaughnessy Ulla
Published: October 2019

Impacts of energy retrofits on IAQ were studied in two European countries, Finland and Lithuania. Air change rates were estimated based on air flows measured through ventilation outlets and 24-hour monitoring of CO2 concentrations before and after various energy retrofits in multi-family buildings. The air change rates (ACR) after retrofits were higher in apartments with mechanical ventilation in Finland. The ACR after retrofits were smaller in all study groups in Lithuania, yet noticeably smaller in apartments with mixed ventilation. CO2 concentrations in all study groups in Finland were lower than in Lithuania. Also, some decrease in CO2 concentrations was noticed after retrofits in Finland, whereas an opposite trend was observed in Lithuania. In conclusion, impacts of energy retrofits were mainly marginally positive in Finland and mainly negative in Lithuania. Positive impacts were typically noticed in apartments with mechanical ventilation and “good” IAQ before retrofits. On contrary, negative impacts were noticed in apartments with natural ventilation and “adequate” IAQ. It was concluded that IAQ should be assessed before and after retrofits.
Conception and deployment of the APOLLINE sensor network for IAQ monitoring
Authors: Hanoune B , Kassi R , Verbeke B , Assy E , Clavier L , Crumeyrolle S , Degrande S , Le Pallec X , Rouvoy R
Published: October 2019

The long-term study of air quality inside buildings in the presence of occupants requires the deployment of low-cost instruments capable of measuring the most concerning pollutants, without nuisance to the occupants. Several laboratories within the University of Lille, France, have united their expertises within the APOLLINE project (Air Pollution and Individual Exposure). They have designed a complete infrastructure for IAQ research and education, based on chemical (NO, NO2, O3, CO, CO2, COV, granulometry of PM 0.4-16 μm) and physical (P, T, RH, light, sound) sensor nodes. The nodes continuously send raw measurements through Ethernet or various wireless technologies to the APISENSE® cloud platform operated by Inria, for offsite realtime visualization and analysis. The network was successfully deployed since July 2018 within the buildings of University of Lille, with interesting results on the pollution levels and occupancy patterns.
Experimental study on the performance evaluation of active chilled beams in cooling operation under varied boundary conditions
Authors: Jean Marc-Antoine , Upadhyay Rohit , Koupriyanov Mike , Mora Rodrigo
Published: October 2019

This study investigates the thermal comfort and indoor air quality performance of Active Chilled Beams (ACB) in cooling operation mode in an open office environment with asymmetrical loads. Many studies on thermal comfort using ACB in cooling mode have been conducted; most of the studies confirm that thermal comfort is satisfactory because the temperature gradient and the airspeeds are acceptable at the occupant level. However, these studies do not specifically address the local discomfort in cooling mode. Furthermore, these studies do not consider performance under different ACB configurations or varied boundary conditions such as those found in real offices. This paper reports the results of an experimental study that addresses the above issues. A laboratory experiment was designed to simulate a multi-occupant open office with an ACB subjected to asymmetric boundary conditions. The results demonstrate that discomfort draft risk at the ankle level is higher when the ACB is oriented parallel to the window. Furthermore, the results suggest that shape (the type of ACB) and throw of ACB affect air distribution. The results emphasize the importance of properly selecting, orienting, and designing ACB, not just to offset the room loads, but to match the proportions and boundary conditions of the office.
Climate and occupancy based investigation of air pollutants in office spaces
Authors: Hashemi Farzad , Passe Ulrike
Published: October 2019

Indoor air quality (IAQ) has long been a matter of public concern as many people are spending a large portion of their time indoors. The concentration of some pollutant in offices and other work places can often be 2 to 5 times higher than typical outdoor concentrations. This study investigates the relationship between office space available per employee and outside weather condition with indoor pollutants level at 25 office locations of a large international architecture and design firm. Air pollutants measured in this study included carbon dioxide (CO2), particulate matter (PM2.5), and volatile organic compounds (VOCs). They have been monitored for a three-month period from December 1st, 2017 to February 28th, 2018 in 23 offices located in the U.S., one office in China, and one office in Dubai. The first phase of this study analyzed the hourly average levels of mentioned pollutants at these offices during working and non-working hours. Then those levels were correlated to the number of employees at all of the locations. The second phase observed the difference in CO2 level, as the most important indoor air pollutant, related to outside weather condition (temperature and humidity) at three locations in the U.S. The initial result of phase one proved the linear relationship between the number of employees and CO2 levels in office buildings. It concluded, that the low area per employee rate will cause the high CO2 concentrations. Moreover, a comparison between indoor CO2 level and outside weather conditions (temperature and humidity) in the second phase at three office shows that CO2 level are affected directly by outdoor conditions during working hours. Based on the building climate zone, when temperature and humidity are far from the comfort zone and mechanical ventilation system are operated, CO2 concentration could variously change during working hours.
Simulation-based analysis of optimized PCM to improve building energy performance and indoor thermal environment
Authors: Hun Park Ji , Wi Seunghwan , Yeol Yun Beom , Yang Sungwoong , Lee Jongki , Kim Sumin
Published: October 2019

The objective of this paper is to evaluate the optimized PCM melting temperature installed in the building models by DesignBuilder and analyze the building energy performance depending on the different climate conditions in South Korea. The building model was followed the residential construction standard house established by the Korea Rural Community Corporation. The total floor area of building is 41.92 m2, and the window-to-wall ratio is 30 %. The HVAC conditions were set to “simple HVAC” which is the basic load calculation algorithms to minimize the heating and cooling loads. Set-point temperatures set to the comfort temperature range, and set-back temperatures are based on the recommendation of the Ministry of Trade, Industry, and Energy of South Korea (MOTIE). The climate conditions to evaluate the simulation analysis were based on the Köppen-Geiger climate classification, which classifies the general climate of the world depending on temperature and precipitation. As a result of the simulation analysis, the maximum energy savings were shown by PCM with melting point of (22.39–24.47)°C in cooling, and PCM with (19.73–21.38) °C in heating. Consequently, the maximum total energy savings were achieved for PCM with (22.39–24.47) °C, which means that the best optimized PCM according to the four seasons.
Thermal comfort and visual interaction: a subjective survey
Authors: d’Ambrosio Alfano F R , Bellia L , Fragliasso F , Palella B I , Riccio G
Published: October 2019

The application of the human factors’ principles stated the need for rethinking the indoor built environment design which should also conjugate the binomial energy saving-Indoor Environmental Quality (IEQ). This means that the optimization of a single IEQ component should also account for possible antagonistic or synergic effects. The hue-heat hypothesis is based on the idea that light and colours can affect the thermal perception. Particularly, spectral power distributions of light shifted to short wavelengths seem to promote a cooler thermal perception and the vice-versa. Several efforts have been made in the past to characterize the effect of the colour of light on thermal comfort, with experiments giving conflicting results mainly due to a bad control of lighting and microclimatic parameters and to the use of not robust measurement protocols. To verify the hue-heat hypothesis, in this study 81 subjects have been exposed to two different lighting scenarios characterized by warm and cool light at a fixed task illuminance value (300 lx) under winter thermo-hygrometric conditions in a special test room provided with white-tuning LED sources. Preliminary findings seem to confirm that warm light results in a warmer thermal sensation with a potential improvement of comfort conditions.
Demand-controlled ventilation: do different user groups require different CO2-setpoints?
Authors: Borgen Haugland Martine , Yang Aileen , Holøs Sverre B. , Thunshelle Kari , Mysen Mads
Published: October 2019

The aim of this study is to investigate whether children’s bioeffluent generation rate is proportional to their carbon dioxide (CO2) generation rate. Consequently, to assess if there is a need to differentiate the CO2- setpoint for different user groups, focusing on children. Perceived air quality (PAQ) and odour intensity (OI) were assessed in three classrooms in Oslo, Norway. Two second-grade classes (7-8 years old) were compared with one eighth-grade class (13-14 years old). An untrained test panel consisting of 16 people visited each classroom twice and were asked to evaluate PAQ and OI upon entering the classrooms. The CO2 levels in the classrooms were kept constant at either 600 ppm or 1100 ppm during each visitation. The results showed that average PAQ-score was significantly worse in the second-grade classrooms compared to the eighth-grade classroom. For perceived odour intensity, the average score indicated that the odour was stronger in the second-grade classrooms compared to the eighth-grade classroom, however, this difference in score was not significant. Our results indicate a need for differentiation of setpoints for CO2-DCV based on user groups, especially for children.
Fusion of environmental monitoring components and gardening modules for manipulating indoor air quality
Authors: Chen J C , Lin Y J , Yang Z L , Yu C C
Published: October 2019

People who live in a crowded jungle of metropolis are easy getting stressed and extremely need relaxing activities, e.g. gardening. The considerations about limited space, busy day and scarce experience will stop people to take action on gardening. They do need a device to help them taking care of plant, a smart device which is able to remotely control would be popular to the business of interior planting. This demand encouraged many designers to create the modules for interior planting. It also pushes researchers to study how interior planting is able to capture particles, to absorb VOC, to transform CO2, to change temperature and moisture. However, planting module with smart control of indoor air quality is rare until now. So we created an environmental manipulator in which environmental monitoring sensors, planting modules, and remote relays are fused together. This study described the process how we get the optimal design of environmental manipulator under a series of interviews based on Evaluation Grid Method (EGM).
Indoor Air Quality solutions for commercial buildings
Authors: Menezes Sean
Published: October 2019

Poor Indoor Air Quality in commercial buildings is a growing concern these days, with several studies suggesting that indoor air pollution is 2-5 times worse than outdoor air pollution. Most individuals spend approximately 8-10 hours a day at their workplace, exposing themselves to dangerous indoor air pollutants such as bacteria, mold, viruses, carcinogenic VOC’s (volatile organic compounds) generated within the office building. Micro-organisms and VOC’s are continuously released in commercial buildings and it is important to effectively keep the counts under control, since the generation of these pollutants are dynamic and cannot be predicted. It is practically not possible to sterilize the people entering commercial buildings and offices and expect them to wear sterile garments, gloves and masks used in clean room environments in the office. We also cannot avoid the use of cleaning agents, adhesives used for furniture and carpets, paints and sanitizers. This challenge sparked off the inspiration to design an innovative and effective solution that addresses the above issues and provides centralized decontamination at the source.

To effectively do this, the solution needs to integrate with the AHU to ensure that all the air circulated within the building is treated and decontaminated. In most AHU designs, the air is recirculated 10 times in one hour and since the IAQ system is integrated with the AHU, it ensures that the air is decontaminated with every pass through the system. The efficacy of the system has been tested and its performance validated in the test facility by a NABL accredited firm, and the proof of concept established practically, with field tests at live installations in fully functional office buildings.
Thermal environment perceptions considering length of stay for cardiovascular inpatients in hospitals: a statistical approach
Authors: Alotaibi Badr S , Lo Stephen
Published: October 2019

Cardiovascular patients are one of the highest population groups affected by elevated external temperatures. Many research studies highlight the impact of three main indicators: mortality rates, morbidity, and admissions to hospitals. Most research determined that cardiovascular patients were among the top admissions to hospitals. The external temperature needs to be evaluated while the patients are hospitalised to reveal the extent of its impact. This study also seeks to evaluate the impact of the length of stay periods on the perceived thermal environment of cardiovascular inpatients when the external temperatures are elevated particularly in summer periods. To do so, longitudinal data analysis of indoor air temperatures, relative humidity and outdoor air temperatures linked with recorded patients’ responses, was undertaken for three months in cardiology and cardiac surgery wards in a hospital in Saudi Arabia, i.e. a hot, arid dessert climate (BWh) based on the Köppen Geiger climate zones map. Patient questionnaires were administrated during the daytime, specifically the afternoon hours to obtain the best results when outdoor temperatures exceeded 40°C. The gathered data was analysed using several statistical tests for correlations and differences to validate the results. The patients who were hospitalised for more than one week and one month felt more neutral compared to other shorter periods of stay; this was interpreted as patients having sufficient time acclimatise to their environment.
Ventilated hollow core slab cooling load reduction under the operative temperature metric
Authors: Christopher Raghubar , Umberto Berardi
Published: October 2019

This paper evaluates the cooling load reduction of a commercial office building through the use of a ventilated hollow core slab in Toronto Canada. Two scenarios were evaluated – SmartVent (SV) in which outdoor air is ventilated through concrete slab hollow cores when the outdoor air temperature is lower than that of the hollow core surface; and NoVent (NV), in which no ventilation takes place. A numerical model was created to simulate the heat transfer between the outdoor air stream and slab; and associated heat transfer between the slab and interior environment. The mean radiant temperature experienced by an occupant was then evaluated in both scenarios to determine the required ambient air temperature to achieve an operative temperature of 24.8°C. The cooling loads required to maintain this operative temperature setpoint were then determined for and compared.
Acoustic Environment of Large Terminal Airside Concourse in China
Authors: Huang Yenhsiang , Zhu Yingxin , Zhang Zhongchen , Lin Borong
Published: October 2019

This study uses the model of the airside concourse of a certain terminal building in China, which is under construction, and compares the indoor reverberation time with six different indoor heights and different situation of unoccupied and occupied indoor field. The results of the study show that due to the narrow design of the airside concourse and the large number of glass curtain walls, the insufficient indoor sound absorption will result in - in the case of unoccupied field - the reverberation time of the 500Hz at 20m height terminal lasts as long as 7.2 seconds. With each 1m lower in height, the reverberation time increases by 0.16 seconds. The conclusion of this study is that, in the case that the indoor sound absorption cannot be increased and the number of indoor people is fixed, reducing the height of the terminal building helps to reduce the indoor reverberation time.
A comparison of indoor air quality and employee absenteeism in ‘local’ and ‘imported’ green building standards
Authors: Elnaklah R A , Natarajan S
Published: October 2019

Buildings are responsible for a quarter of global carbon emissions. In the developing world, the desire to reduce energy consumption initially resulted in the adoption of ‘imported’ standards such as LEED and BREEAM and, over time, the development of several ‘localised’ standards that either supplant or compete with the imported standards. However, such standards have often been implicated in the unintended consequence of reduced indoor air quality resulting from lowered ventilation rates, in turn affecting employee productivity and absenteeism. Here, we systematically review and compare the performance of office buildings built to the localised Jordanian Green Building Guide (JGBG) and the well-known international LEED standard. We measure building performance in terms of the indoor air quality (via CO2 concentration) and occupant absenteeism during winter 2019. Results show that the JGBG building had a significantly lower mean indoor CO2 concentration than the LEED building during working hours (p < 0.00). In addition, the occupants in the JGBG building reported 20% more working hours (p < 0.03) and approximately 9 hours less of absolute absenteeism. These initial results suggest that further development of localised codes is likely to bring greater benefit to the performance of building and occupants compared to imported standards.
The impact of internal gains on thermal stratification for public buildings
Authors: Laghmich Nisrine , Romani Zaid , Lapisa Remon , Draoui Abdeslam
Published: October 2019

The indoor temperature in public buildings varies according to its internal loads scenario. In fact, this building typology in temperate climates is generally non-air conditioned and naturally ventilated. In order to improve indoor thermal conditions with appropriate solutions, it is necessary to study the vertical temperature profile. The main objective of this study is to show the impact of thermal stratification on thermal comfort of public buildings. The thermo-airodynamic modeling using TRNSYS(C) and CONTAM(C) have been performed in this numerical simulation study. The indoor air volume is vertically subdivided into several levels to evaluate the evolution of temperature profile taking into account the different inside-outside air exchange and air coupling between sub-zones. This study is performed in the city of Morocco that represents Mediterranean climate region with a moderate temperature. The effect of several parameters, such as indoor occupation pattern, internal lighting, sub-zones air exchange and vertical thermal stratification are studied. Numerical simulation results show that thermal stratification of buildings affects the occupant’s comfort level
Understanding indoor environmental conditions and occupant’s responses in houses of older people
Authors: Soebarto Veronica , Williamson Terence , Carre Andrew , Arakawa Martins Larissa
Published: October 2019

In Australia, the vast majority of older people, those aged 65 years and over, want to live at their own homes for as long as possible. Older people are, however, vulnerable to extreme conditions, hot or cold, and therefore it is crucial to ensure that the home’s indoor environmental conditions are conducive to their health and well-being. The first step to do this is by understanding the existing conditions in homes of older people so that appropriate steps for improvements can be taken. This paper presents an on-going study to understand the indoor environmental conditions and occupant’s responses in homes of older people in South Australia. The study is conducted using a robust indoor environmental monitoring system that is integrated with a user-friendly occupant survey system using an electronic tablet, allowing the occupants to reflect on their “right here right now” experience over different seasons in a year. The paper discusses the development of this integrated system and reports some preliminary data. Preliminary results showing the associations between measured environmental data, such as dry bulb temperature, radiant temperature, air velocity, and CO2 level, and thermal sensation, comfort, perception of indoor quality and self-reported health/well-being will also be presented.