bluuebunny/crossref_metadata_2025 huggingface dataset:
CFD Evaluation of Directional Variation Effects of the Air Supply Diffuser for the International Space Station Cabin Atmosphere
Authors: Ivanov Nikolay , Smirnov Evgueni , Son Chang H. , Telnov Denis
Published: August 2019

The International Space Station (ISS) crew health and safety depend on ventilation system performance. The ISS ventilation system comprises of numerous air supply diffusers. For each ISS module design of the ventilation system and, in particular, supply diffuser distribution and configuration, is based on the assumption that the cabin aisle way is clear of any objects. However, on-orbit operations could lead to short- or long-term blockage of the area near the air supply diffuser due to some items or stowed bags necessary for the station operation. Partial blockage of the diffuser could disrupt the free jet airflow or change its intended direction. The current contribution is devoted to examination of the ISS research module – the U.S. Laboratory – ventilation system performance in case of partial inlet diffuser blockage with objects, such as Cargo Transfer Bag. The goal of the study is to assess the localized effects when the blockage occurs in the module interior for a possible stagnant zones formation. The paper presents detailed analysis of the diffuser blockage effects on airflow characteristics in various zones in the ISS habitat.
Effect of Cross-Ventilation and Solar Irradiation on IAQ as a function of Roof Angle
Authors: Atalar Anil B. , Cakan Murat
Published: August 2019

Natural ventilation is the most conventional and one of the significant alternative applications for energy efficiency. Cross-ventilation is commonly used in hospitals, shopping centres or greenhouses. In this study, cross-ventilation for a greenhouse was investigated. The greenhouse buildings may differ in design depending on the region and climate. Therefore, when natural ventilation methodology is carried out in these buildings, the effect of solar radiation should also be taken into consideration. There have been many studies on natural ventilation in the literature, but while these studies have been conducted, the impact of solar irradiation has never been combined. In the present study computational geometry was created according to 4 different roof inclinations: 0°, 15°, 30°, and 45° - provided that the inlet and outlet opening positions are fixed. Moreover, each inclination was simulated at the following hours of the day: 10:00, 13:00 and 16:00 in June. The hex-dominant grid was created for a computational domain using Cut-cell method and Renormalization-group (RNG) k-ε turbulence model provides the best results and efficient computational cost. In addition to this, Discrete Ordinates (DO) radiation model with SIMPLE algorithm was implemented for solar radiation effect. In order to decrease the temperature of the reference line, the evaporating cooling methodology was performed and a new PVC cover material was applied. Numerical predictions show that solar irradiance combined with roof inclination and outlet opening position has a significant effect on velocity and temperature distribution inside the building space. The air mass flow rate which aspirates from outlet increases considerably when the inclination angle is increased, also flow character changes according to configurations. Evaporative cooling creates a decrease in temperatures on the reference line up to 2 – 2.5°C when compared with the reference model.
Performance assessment of demand controlled ventilation controls concerning indoor VOC exposure based on a dynamic VOC emission model
Authors: De Jonge Klaas , Janssens Arnold , Laverge Jelle
Published: August 2019

The performance assessment of ventilation systems often focusses only on CO2 and humidity levels. The indoor Volatile Organic Compounds (VOC) emissions of building materials or other products is thereby overlooked. The new generation of ventilation systems, Demand Controlled Ventilation (DCV), are systems that do not supply the nominal airflow continuously but are controlled by CO2 or humidity sensors in order to save energy. This poses potential problems for exposure to VOCs. In this study, a dynamic VOC model, which takes into account changing temperature and humidity that was derived from literature, is implemented in a CONTAM model of the Belgian reference apartment. The impact of a DCV system on the indoor VOC levels is investigated. Results show that the use of a dynamic model is necessary compared to the previously used approximation of a constant emission. Furthermore, on a system level, the influence of the ventilation system control on the indoor VOC levels shows. The overall VOC concentration in the different rooms will be higher because of lowered ventilation rates. Especially in rooms that are often unoccupied during the day, the accumulation of VOCs shows. In the development of DCV system controls, the aspect of VOC exposure should not be overlooked to be able to benefit from both the energy savings and improved Indoor Air Quality (IAQ).
Numerical study of the effect of wind on the cooling of photovoltaic panels
Authors: Koita Dakouo , Popa Catalin-Viorel , Robert Bruno , Galatanu Catalin-Daniel
Published: August 2019

The main objective of this study is to optimize the production of electricity from a photovoltaic (PV) plant with a capacity of 50MWc. The power plant is located near the city of KITA, Mali, in an area whose climate is characterized by high temperatures. However, the temperature of photovoltaics cells plays a key role in their performance, which deteriorates when the temperature increases. In this study we focus on the analysis of laminar forced convection flow around a PV panel, main element of a photovoltaic plant, considering the ambient temperature, irradiation as well as the velocity and the direction of the wind. Several operating configurations were analysed in relation to the specific climatic conditions of Mali for a typical day of sunshine with a daily irradiation of a duration of 12 hours between 6:00 and 18:00. The mass transport, momentum and energy equations are solved numerically using the finite volume method. This method is based on the spatial integration of transport equations with respect to elementary control volumes. Computer simulations are performed with ANSYS Fluent® CFD commercial software. Our results show that considering the effect of wind plays an important role in the temperature estimates of photovoltaic cells and that accurate knowledge of this behaviour is essential for optimizing production.
Solar Powered Mechanical Ventilation: A case study
Authors: Birtürk Aslı , Ekren Orhan , Aktakka Sinan , Özel Özdem , Toksoy Macit
Published: August 2019

In this study, a solar powered mechanical ventilation unit has investigated and tested in terms of efficiency and performance. Test unit can be divided into two parts, the first one is ventilation unit with 370 m3/h max airflow rate and max 167 W fan power provides fresh air for a residency and recovers heat from the climatized exhaust air. Total area is 70 m2 for the residency and total occupant is four. The second part of the test system is solar energy power system with two 325 W polycrystalline photovoltaic panels, an inverter and two batteries. The mechanical ventilation unit has energized by a solar photovoltaic system; if the solar energy is not available then ventilation unit has connected to the national electricity grid. This is an alternative option to consumers to use electricity by the grid in case the PV system does not produce enough energy because of the usage or the technical problems or the weather conditions based on the seasons. On the other hand, in some cities, number of photovoltaic panels rolled up upper number according to solar energy potential and therefore resulted excess electricity has assumed to sell to the national grid. According to the results, the test system is able to operate at maximum ventilation necessity and power consumption without grid connection in Izmir. Furthermore, we have compared Izmir and Romania in accordance with feasibility for the same mechanical ventilation system at max flow rate and required ventilation rate is determined depends on daily usage scenario of the room.
Analysis and Discussion of Baoji “Shigu • Tian Xi Tai”, “Shigu • Sun City” Ground Source Heat Pump Energy Station System
Authors: Ji LI , Bin CHEN , Jintang LI , Chonghua CHENG , Zhenwu GAO , Xiaomei FENG , Ya MA , Chun YANG , Rui DU , Biao QIAO
Published: August 2019

Baoji “Shigu • Tian Xi Tai”, “Shigu • Sun City” ground source heat pump energy station system is an important energy supply project in Shigu. In this paper, we systematically introduce the design of green building and ground-source heat pump system, points of construction process, pre-cooling station technology, EMC economic model in detail. In addition, the ground source heat pump system of the project was tested in the field to analyze and evaluate the running performance of the system. We hope our research can provide some reference and help to the practitioners.
Experimental and numerical study of the domestic hot water production with PV panels and a heat pump
Authors: Aguilar F. J. , Crespí D. , Quiles P. V.
Published: August 2019

This article presents an experimental and modelling work which uses a compact domestic hot water heat pump (DHW-HP) that is simultaneously powered from photovoltaic panels (PV) and from the grid. Results from more than 240 days of experimental works have been used in order to develop and to validate the computer model of the system. The program, implemented in MATLAB, is computationally ‘light’ enough to allow mid-term simulations yet also detailed enough to accurately and coherently portray stratification within thermal storage tanks. Finally, as an example of the model capabilities, it has been used to simulate a domestic hot water tapping cycle from the European Standard EN 16147.
Sensitivity analysis using simulations for a ground source heat pump – implementation on a solar passive house
Authors: Ilisei Gheorghe , Catalina Tiberiu , Gavriliuc Robert
Published: August 2019

Having in sight the need for a strong reduction in CO2 emissions and the fluctuation of the price of fossil fuels, the ground source resources alongside with the ground source heat pumps are becoming more and more widespread for meeting the heating/cooling demand of several types of buildings. This article targets to develop the thermal modelling of borehole heat storage systems. Trying to emphasize some certain advantages of a GSHP (ground source heat pump) with vertical boreholes, a case study analysing a residential solar passive house is presented. The numerical results are produced using different modelling software like DesignBuilder, EED (Earth Energy Designer) and a sizing method for the length of the boreholes (ASHRAE method). The idea of sizing the length of boreholes (main design parameter and good index in estimating the system’s cost) using two different methods shows the reliability of this modelling tool. The study shows that borehole’s length of a GSHP system can trigger a difference in electricity consumption up to 22%. Moreover, this sensitivity analysis aims to prove that the design of the whole system can be done beforehand just using modeling tools, without performing tests in-situ.
Climate change and building technologies: investigations of future weather scenarios on building energy performance
Authors: Kierdorf Daniel , Hahn Jakob , Lang Werner
Published: August 2019

This paper aims to investigate the impact of future climate on building systems, taking account of a strict building standard. A building is modelled in TRNSYS regarding a sustainable heating and cooling energy production by solar heating and radiative cooling in combination with water storage tanks. Sensitivity analyses (Morris Method) are performed for the technical building configurations for the years 2030, 2050 and 2100 (REMO climate model). They are compared and evaluated with the current reference climate (TRY) of 2017. The objective is to show which components have a significant influence on the energy consumption of buildings. Furthermore, due to the climate change sustainable building technologies are necessary. This paper demonstrates how the influence of the climate can be counteracted from the perspective of building services. Global warming requires a rethink of the interaction between building design, building technologies and climate. In this point building services engineering offers the most flexibility. By performing parameter studies, early knowledge about the building and its required technology can be gained. The target value of this study is the indoor air temperature as a function of the outdoor temperature. The objective function corresponds to specifications according to the European standard EN 15251. Following the parameter studies, optimization processes are carried out.
Comparison of Performance of Desiccant Air Handling Unit with Solar Thermal System under Various Control Methods
Authors: Ukai Makiko , Okumiya Masaya
Published: August 2019

In hot and humid summer as in Japan, dehumidification is important process for air conditioning. Desiccant air handling unit is one of the major system for dehumidification in which absorbent or sorbent absorbs moisture in the air and hot heat source is required in order to regenerate them. In order to use solar thermal energy efficiently, flexible control, which controls the distribution of the dehumidification at precooling coil and dehumidification wheel, is proposed and analysed its performance through simulation. Simulation results show that supply absolute humidity fulfils the set point even when solar thermal energy is not supplied to regenerating coil under flexible control. On the other hand, system with conventional fixed control can not fulfil the set absolute humidity when solar thermal energy is not supplied. The unprocessed latent heat load is around 49kW, which results in higher relative humidity around 56.5%. Solar thermal energy supplied to regenerating coil under flexible control is larger than fixed control.
Performance evaluation of different micro-CHP configurations in real life conditions and the influence of part load behaviour
Authors: Verhaert Ivan , Van Riet Freek , Baetens Robin , De Pauw Margot , Van Erdeweghe Michiel
Published: August 2019

Micro-cogeneration (micro-CHP) is an emerging technology to reduce the non-renewable energy demand in buildings and reduce peak loads in the grid. Within building applications internal combustion engines, Stirling engines and CHPs based on fuel cell technology are mostly used. The heat and electricity demand here is often characterized by a strong fluctuation over time. The design and control of micro-CHP in buildings is therefore often more challenging in order to achieve its nominal efficiency. In a recently ended research project, different micro-CHP-technologies were evaluated based on on-site measurement campaigns. In practice, micro-CHP is hardly ever used as single technology to deliver the necessary heat. A poor hydronic design can strongly reduce the number of operating hours of the CHP and even its performance, which is influenced by e.g. return temperature. In this paper the performance and behaviour of different technologies are discussed with a strong focus on the part load and start-stop behaviour. The necessary insights are provided with respect to system integration and control and are illustrated with a discussion on the executed measurement campaign in the region of Flanders.
Effect of Desiccant Solution Temperature on Regeneration Performance of a Cross-Flow Regenerator
Authors: Dong Hye-Won , Cho Hye-Jin , Jeong Jae-Weon
Published: August 2019

The purpose of this study is to investigate the effect of the inlet solution temperature on the performance of an adiabatic cross-flow regenerator using a lithium chloride (LiCl) aqueous solution, and to propose the optimal inlet solution temperature when operating this type of regenerator. In the experimental tests, the inlet solution temperature range varied from 50 to 90°C. The tests were carried out at 10°C intervals while the other conditions remained constant. The measurement parameters for the test were the inlet air dry-bulb temperature and humidity ratio, outlet air dry-bulb temperature and humidity ratio, air volume flow, solution density, and inlet and outlet solution temperatures. The regeneration effectiveness and coefficient of performance (COP) were selected to assess the heat and mass transfer performance of the cross-flow regenerator. The most important finding of this research was to determine the optimal solution inlet temperature in the cross-flow regenerator with the LiCl aqueous solution considering both the regenerator performance and energy consumption. The test results show that the recommended inlet solution temperature is 60°C, considering both regeneration effectiveness and COP.
Energy-saving potential of dedicated outdoor-air system assisted by vacuum-based membrane dehumidifier
Authors: Cheon Seong-Yong , Yoon Soo-Yeol , Liu Su , Jeong Jae-Weon
Published: August 2019

The proposed research presents a dedicated outdoor-air system (DOAS) integrated with a vacuumbased membrane dehumidifier (VMD). The primary objective of this study was to evaluate the energy-saving potential of the proposed VMD–DOAS combination. VMD–DOAS comprised a membrane-energy exchanger (MEE), dew-point indirect evaporative cooler (DP-IEC), and VMD. VMD possessed a characteristic by virtue of which the dehumidification process was isothermal; i.e., no temperature change was observed during the VMD process. While VMD served to control the dry-air supply, the required target temperature (i.e., 17 °C) was maintained via DP-IEC operation. The remaining sensible heat of the conditioned zone was controlled by the ceiling radiant cooling panel (CRCP). The load of the conditioned zone was driven by TRANSYS 18, and an engineering equation solver (EES) was used for evaluating the energy-saving potential of the proposed system with CRCP by comparing it against the variable-air-volume (VAV) system. Results of this study demonstrated that the proposed DOAS with CRCP consumed 37% less operating energy compared to the VAV system. This observed energy-saving potential of the proposed system was driven by reducing the dehumidification load and subsequent energy recovery by MEE.
The Effects of an Air Conditioning System using the Coanda Effect on an Indoor Office Environment
Authors: Igarashi Hitomi , Akimoto Takashi , Hatori Daisuke , Kato Shun , Sakakibara Hikari , Kimura Madoka
Published: August 2019

In this study, we propose a ductless air conditioning system using the Coanda Effect for a medium size office building to achieve a net-zero energy building (ZEB). The indoor temperature environment and air flow characteristics during cooling and heating conditions created by this system were evaluated. In addition, to validate the computational fluid dynamics (CFD) analysis results when the heating system was activated, the results were compared with the measurement results. The investigation indicated that for cooling, a good thermal environment could be established in the residential area; however, local draught continued to be an issue. For heating, it was confirmed that heating of the residential area could be accomplished using floor suction. In addition, it was shown that the accuracy of the CFD analytical results can be improved by adjusting the input conditions to the actual conditions.
Numerical Analysis for Smoke Spread in an Aircraft Hangar
Authors: Khalil Essam E. , Haridy Hatem Kayed , Ahmed Eslam Said Abdelghany , Mohamed Ahmed Ashraf
Published: August 2019

Smoke is one of the most dangerous factors in aircraft hangar in case of fire. As it causes reduce in visibility and deaths due to high temperature or toxicity also prevents applying evacuation plan for workers. This study present numerical analysis for improving traditional system of ventilation system to manage smoke produced due to push-back vehicle on fire at hangar. By studying effect of changing extraction and supply rates, the number of extraction and supply fans, and the arrangement of extraction and supply fans on the visibility, temperature and air velocity at human level to insure not to exceed limits stated by NFPA 130[1] to apply evacuation plan for workers. The study is performed using Fire dynamic simulator to simulate 16 case studies in the hangar of airports in Brandenburg. The hangar has the outer dimensions of 83.40 m width and 77.60 m depth and thus an inner area of approx. 6,472 m2. The hangar has a medium interior height of approximately 18.20 m. The results show that using extraction fans with rate (ACH) double the supply rate for the traditional ventilation system gives very good results in controlling the smoke. As well as, decreasing the number of supply fans will make the smoke spread rate inside the hangar lower, which helps to control the smoke spread of fire in less time.
Demand-oriented Hydronic Heating System and the Active One-pipe System Design Tool
Authors: Ondřej Zlevor , Jiří Dostál
Published: August 2019

This article is focused on hydronic heating systems that use pumps as the control actuators instead of valves. Those systems are called “demand-oriented”, while the systems being controlled by valves are called “supply-oriented”. Reader gets an overview of various versions of both demand- and supply-oriented systems using both one- and two-pipe topologies, supported by a brief historical outline, current state of the art and basic advantages and disadvantages of the introduced hydronic systems. The special interest is given to the one-pipe demand-oriented systems, which offer several benefits in comparison with nowadays widespread systems (mainly supply-oriented two-pipe), however, the computation complexity of design of such systems inhibits their more frequent utilization. This paper also introduces a computation and optimization tool to help with the design of one-pipe demand oriented hydronic heating systems, which eases the designer to size the AHU (Air Handling Units) and to set the mass flows of fluid in the system branches.
Study on Reproduction of Thermal Plume over a Gas Stove by CFD
Authors: Kiyosuke Hayato , Kurabuchi Takashi , Toriumi Yoshihiro , Simanuki Yuki , asawa Yasuhisa
Published: August 2019

In order to create a comfortable environment in the work place around commercial kitchen, it is desirable to accurately predict the capture efficiency of exhaust from the cooking appliance by CFD. Due to insufficient diffusion in buoyant plume, however capture efficiency tends to be overestimated in the k-ε model. In this study, we confirmed that the problem of the k−ε model in the prediction of plume is originated from the buoyancy production of the turbulent kinetic energy by comparing among the measurement value, simulated results using the LES model and the k−ε model, and possible remedy for discussed.
Simplified Prediction Method of Vertical Temperature Distribution for Impinging Jet Ventilation System
Authors: Kobayashi Tomohiro , Nishiumi Toshiya , Umemiya Noriko
Published: August 2019

The impinging jet ventilation (IJV) system is an air-distributing strategy to generate a thermal stratification in a room by supplying the air vertically toward the floor, which provides higher ventilation effectiveness than mixing ventilation. To date, however, no simplified prediction model of indoor thermal environment for an impinging jet ventilated room has been established. Therefore, this study aims to propose a simplified calculation model based on “Block Model”. This paper first presents a parametric study using Computational Fluid Dynamics (CFD), where total supply airflow rate of a test room is changed as a parameter. The number of terminal is also changed. Secondly, the paper presents the simplified calculation model of vertical temperature distribution based on block model that solves heat flow by advection and diffusion. Here, in this prediction model, the most important parameter is the turbulent thermal diffusivity between two room-space blocks in vertical direction. The room-space blocks are classified into two types, i.e., lower and upper part of a room. Based on parametric study using CFD, turbulent thermal diffusivity is arranged for lower and upper block respectively, and it is finally shown that the vertical temperature distribution from block model well agrees with CFD result.
Human-Oriented Design of an Indoor Thermal Environment
Authors: Ukai Masanari , Nobe Tatsuo
Published: August 2019

In this study, an initial survey of clothing insulation and changes in the metabolic rate of individuals in office spaces was performed to establish the distribution of room temperatures at which individuals perceived a neutral thermal sensation. Subsequently, the indoor thermal environment in four offices was surveyed during the summer with different air-conditioning systems to determine the thermal environment stability in each case. The results revealed that for the required temperature, there was a noticeable difference between the average and most frequent values. Moreover, it was determined that the required temperature distribution is not normal, but rather, it is skewed to the low-temperature side. In addition, the radiant air-conditioning system was found to generate a narrow distribution of the equivalent temperature and hence, facilitated a more uniform thermal environment compared to a convective (multi-unit) air-conditioning system. Therefore, in buildings with convective air-conditioning systems, even if the planar average thermal environment is categorized as comfortable, it may be possible that workers who are sensitive to the cold or heat will complain of discomfort more frequently than those in buildings with radiant air-conditioning systems because the probability of workers sitting in cold- or hot-spot areas is higher in the former case.
Indoor climate and energy performance in nearly zero energy day care centers and school buildings
Authors: Ahmed Kaiser , Kuusk Kalle , Heininen Henrik , Arumägi Endrik , Kalamees Targo , Hasu Tero , Lolli Nicola , Kurnitski Jarek
Published: August 2019

This study presents the assessment of actual indoor climate condition and energy performance in eight NZEB school and daycare centers of NERO H2020 project. Physical parameters such as indoor temperature, relative humidity, CO2, airflow rate and temperature were measured during heating and cooling seasons, in parallel with an occupants’ questionnaires survey. Besides, calculated and measured energy data was collected from energy performance certificates and energy bills. Thermal comfort and IAQ were assessed based on categories in EN15251 standard with color footprints. Results showed that all the buildings had good or excellent indoor climate during the heating season. However, a large percentage of occupied hours were categorized as category IV during the cooling season, which mainly occurred due to too low indoor temperature caused by the low outdoor temperature during the measurement period. Also, all buildings achieved low CO2 levels. Moreover, the conducted questionaries’ survey showed good correlation with measured results for all buildings except in one building, which had odor and noise problems. In contrast, the measured energy use in 5 buildings out of 7 was increased by factor 2.1-3.0 compared to calculated annual energy use due to a full-time operation of the ventilation system and presence of hot kitchens.
Evaluating the cooling capacity of diffuse ceiling ventilation system – Full-scale experimental study
Authors: Rahnama Samira , Nielsen Peter Vilhelm , Afshari Alireza , Bergsøe Niels Christian , Johra Hicham , Jensen Rasmus Lund
Published: August 2019

Diffuse ceiling ventilation system is an air distribution system in which part of the suspended ceiling made of perforated panels is used as an air diffuser for the supply of fresh air. This method has been proven to have a higher cooling capacity compared to conventional air distribution systems. The cooling capacity of the system, however, depends on several parameters. This paper presents evaluation results regarding the cooling capacity of the diffuse ceiling ventilation system in connection to two essential parameters, i.e. the distribution of heat sources in the room and the ratio of perforated to non-perforated panels in the ceiling. The evaluation is based on full-scale experiments performed in a laboratory controlled environment and using a design chart which expresses the limits on the supply airflow rate and temperature. The experimental results indicate that the highest cooling capacity is achieved when the heat sources are distributed evenly and the perforated panels cover the entire ceiling. In the case of partial coverage, the cooling capacity is reduced when the heat sources are placed below the perforated panels. The system can have a higher cooling capacity in the partial coverage configuration compared to the full coverage one depending on the supply airflow rate.
Non-uniformity in outdoor CO2 concentration in city of Copenhagen
Authors: Takahashi Hiroki , Bivolarova Mariya Petrova , Keli Athanasia , Nickel Jürgen , Melikov Arsen Krikor
Published: August 2019

The accurate data of outdoor CO2 concentration are important for the proper design of ventilation and thus for indoor air quality and energy use in buildings. Typical design practice is to assume outdoor CO2 concentration to be 400 ppm. However, the outdoor CO2 concentration may be different in different areas of cities. This paper presents preliminary results of long-term (one year) outdoor CO2 concentration changes in four districts of Copenhagen (Denmark). The districts included downtown area and suburbs with different surroundings. Four buildings were selected for the measurements, one building in each district. Outdoor CO2 concentration measurements were performed at two levels – ground level and top of the buildings. Special attention was paid to use accurate measuring instruments. The instruments were carefully calibrated before the measurements. The calibration of the instruments was checked periodically. In this paper, preliminary results from summer and autumn measurements are presented. The outdoor CO2 concentration varied over the day and from day to day in the range between 340 and 450 ppm. The CO2 concentration at the ground of the buildings was usually 10 to 40 ppm higher than that at the top level in autumn. At the buildings in the suburbs, during the working hours, the outdoor CO2 concentration measured on the top level close to the intake duct was on average 408 ppm. At the building in the downtown area, that was on average 414 ppm. However, the outdoor CO2 concentration varied depending on the building, level and time. During the working hours, the 75 percentiles of outdoor CO2 concentration varied between 384 ppm and 442 ppm, which indicates that the required ventilation rate could be different over 10% depending on the building location site, measurement height and time. In order to ensure the required indoor limits of CO2 concentration, CO2 measurements must be performed close to the location of the outdoor air intake.
Use of low-cost PM-sensors to determine the infiltration of outdoor particles into indoor environments
Authors: Drzymalla Jan , Henne Andreas
Published: August 2019

Whether due to traffic, industry or private households – particulate matter enters our air every day and pollutes the air we breathe. When the term air pollution is used, hardly anyone ever thinks of the air inside their own home. However, many urban residences are located in the immediate vicinity of busy roads with high concentrations of particulate matter. Consequently, the outside concentration of fine dust has considerable influence on the indoor concentration. Given the fact that many people spend more than 90 % of their lifetime indoors, it is important to measure and understand particle transport from the outside to the inside in order to assess the effects of exposure to outdoor particles on human health. A two-room apartment near a main road in Leverkusen, North Rhine-Westphalia, Germany was used in the investigation in this research project. Particulate matter concentrations for PM2.5 and PM10 were measured simultaneously inside and outside of the building. Results are size-specific deposition rates, indoor/outdoor ratios and infiltration factors, which provide information on the relationship between internal and external concentrations and the associated health consequences. The particulate matter concentration was measured using low-cost PM-sensors, which were developed and calibrated within the scope of this research project.
Mock-up Test for NOx Reduction by Photocatalyst Paint for Indoor Use
Authors: Song Yong Woo , Kim Min Young , Park Jin Chul
Published: August 2019

In this study, the photocatalyst TiO2 was mixed with a general paint and applied on indoor walls as part of a mock-up test to measure the reduction in the NOx concentration affected by the on or off state of a UV lamp. The findings may be summarized as follows; the NOx concentration was reduced by approximately 7% more (0.134 ppm) with the UV lamp on than when the lamp was off in the indoor space where the paint mixed with TiO2 was applied.
Assessment of Thermal Environment in a Kitchen with a New Ventilation System
Authors: Liu Sumei , Zhou Xiaojie , Liu Xuan , Lin Xiaorui , Qing Ke , Zhang Weizhen , Li Jian , Dong Jiankai , Lai Dayi , Chen Qingyan
Published: August 2019

Chinese kitchen environment is usually hot and humid in summer and cold in winter, while housewife spends considerable time there. This investigation developed a new ventilation system for Chinese kitchens to improve thermal comfort level. To assess the thermal performance of the ventilation system, 32 cooks were asked to prepare the same dishes in the kitchen with or without the system in summer in Changsha, China. The assessment was carried out by subjective questionnaire survey on thermal sensation vote (TSV) and objective on-site measurements of the indoor air temperature and cook’s skin temperature. The indoor air temperature was measured at different locations in the kitchen. The skin temperature was measured at 18 body parts of the cooks. The results show that the thermal environment in the kitchen was non-uniform and local thermal sensation had a great influence on the whole body sensation. Without the new ventilation system, the cooks complained that the hottest parts were thorax, head and face areas. Reasonably good correlation existed between the cooks’ skin temperatures and their thermal sensation votes. The increase of cooks’ skin temperature with the ventilation system was lower than that without the ventilation system. TSV was improved with the new ventilation system.
Effect of Zero Air Change Rate On Particle Dispersion in A Room with Floor Heating
Authors: Mutlu Mustafa
Published: August 2019

Dispersion of airborne particles in the office and residential areas should be well known as these particles in an enclosed volume has a significant effect on human health. In this study, the effect of the floor heating system, which is often preferred by end users due to the energy efficiency of low heating systems, on particle distribution in a room was investigated numerically. It is essential to examine the floor heating having a significant place among low heating systems, concerning particle dispersion. In enclose volumes, ambient air should be replaced with fresh air that is supplied from outdoor in order to ensure indoor air quality. However, the ideal air change rates may not be met for daily use, even in some cases air change rates might be zero. Therefore, in this study absence of air change were assumed, and after temperature and velocity distributions were determined, five different sized particles were tracked by using Eulerian-Lagrangian model. Additionally, three heating capacities (35 W/m2 41.25 W/m2 and 47 W/m2) of the floor heating system were investigated. In this study, where computational fluid dynamics were used, the effect of drag, lift, thermophoretic and Brownian forces were considered. It was found that particles were settled on walls and ceiling due to zero air change rate, and particle concentration rises in the lower part of the wall as particle diameter increases.
Relationship between attributes of individual workers and concentration at work
Authors: Sugino Reo , Tanabe Shin-ichi , Takahashi Mikio , Tokumura Tomoko , Wada Kazuki , Kuroki Tomohiro , Nakagawa Jun , Shinoda Jun , Shinoyama Takuma
Published: August 2019

Working environments are becoming far more diverse. For example, Activity-Based Working (ABW), a new style of working where workers choose their own work environment, is now attracting attention. An office that introduces ABW is comprised of various spaces, including open plan workspaces, corresponding to the ways of working. However, such an office may result in distraction. Therefore, it is necessary to identify the environmental factors that affect individual workers’ concentration at work. This study aimed to ascertain the relationship between individual workers’ attributes, such as the Big Five personality traits, personal control, and age, and the factors that distract them from their work. A questionnaire-based field survey was conducted at an office that partially adopted ABW to investigate the relationship between selection of seats and concentration at work. The results revealed different tendencies among workers for the type of work environment needed to concentrate according to their individual attributes. Additionally, it was suggested that the changing of seats lead to improved concentration at work, thus increasing productivity.
The effects of indoor and outdoor air pollutants on workers’ productivity in office building
Authors: Becchio Cristina , Bottero Marta Carla , Corgnati Stefano Paolo , Dell’Anna Federico , Fabi Valentina , Lingua Carola , Prendin Leonardo , Ranieri Micaela
Published: August 2019

In the present-day society, people spend about 80% of their time inside buildings, and specifically 30-40% in workplaces. From this evidence, the indoor environmental quality needs to be investigated, and in particular, the possible sources of indoor-outdoor pollutants and their impact on the human health, comfort and productivity. First, through an examination of the indoor sources of pollution, the research analysed the main substances that affect indoor air quality in an office. Second, the pollution of external origin and its effects on the performance of employees were taken into consideration. Two scenarios were designed for a Heating Ventilation Air Conditioning (HVAC) system in an office building; one by the installation of a biocidal filter and the other by a traditional one. Two methods were applied to evaluate and compare those scenarios; the Cost Benefit Analysis and the Monte Carlo Simulation. From a financial point of view, the investment and management costs of the filters were considered. Instead, the annual benefits included increasing productivity and reducing days of absence from work due to illness. The results confirmed the energy and socio-economic efficiency of the antibacterial filter; it can be considered a solution to achieve the best income.
Human response to the thermal indoor environment created by a radiant, and a combined radiant and convective cooling system
Authors: Kazanci Ongun B. , Khovalyg Dolaana , Iida Takayoshi , Uno Yoshitaka , Ukiana Tomo-oki , Olesen Bjarne W.
Published: August 2019

This study reports the main findings from a series of human subject experiments, where the subjects were exposed to the different indoor environments created by different cooling systems. The studied systems were a radiant cooling system (chilled ceiling and mixing ventilation, CCMV), and a combined radiant and convective cooling system (radiant diffuse ceiling ventilation, RDCV). The experiments were conducted in a climate chamber under controlled conditions. The climate chamber was configured as a two-person office room. 24 human subjects (12 female and 12 male) were chosen. The exposure lasted three hours and the participants were allowed to work on their own tasks (normal office work) during the exposure. The cooling load was 54 W/m2 and the room temperature at a reference location was kept constant at 26°C (summer conditions). The results show that under both systems, whole body thermal sensation was between slightly warm and neutral (closer to neutral with the RDCV system), and the overall thermal acceptability was almost the same for both systems (close to clearly acceptable). The satisfaction of the human subjects with the thermal environment was very close under the two systems; between satisfactory and slightly satisfactory (closer to satisfactory). Air movement acceptability (slightly higher and closer to clearly acceptable with the RDCV system) was also very close with the two systems. The results of the human subject experiments agree well with the physical measurements of the thermal indoor environment and confirm that the studied systems created very similar thermal indoor environments.
Coupling of a cardiovascular model with a thermoregulation model to predict human blood pressure under unsteady environmental conditions
Authors: Takahashi Yoshito , Oata Masayuki , Asaka Jun-ichi , Nomoto Akihisa , Tanabe Shin-ichi
Published: August 2019

We coupled a cardiovascular model with a thermoregulation model to predict human blood pressure in unsteady environmental conditions. Our cardiovascular model is a lumped parameter model and consists of 42 segments, which include the entire artery and vein system, divided into 18 segments; the heart, divided into 4 segments; and the pulmonary artery and vein. The vessel parameters were adjusted on the basis of local body blood volume and flow of the thermoregulation model in a thermoneutral environment. Blood pressure under unsteady environmental conditions is predicted by changing the heart rate and vessel resistance of the cardiovascular model which is controlled by blood flow that the thermoregulation model predicts. It is possible to predict the increase in blood pressure under cold environmental conditions and the increase in cardiac output under hot environmental conditions and when bathing. The model was validated by simulating bathing experiments. As the result, the model predicted the peak blood pressure later than the experimental data in a cold environment. To improve the accuracy of the model, it is necessary to consider a method for controlling the heart rate, vessel resistance, and gravity effects after a change in posture.
Experimental and numerical analysis of indoor environmental conditions in two physiotherapy facilities in Northern Italy
Authors: Zaniboni Luca , Pernigotto Giovanni , Gasparella Andrea , Mahdavi Ardeshir
Published: August 2019

The comfort conditions are fundamental for the well-being of the occupants of a building. The design of both building envelope and HVAC and lighting systems has primarily to keep high quality levels of indoor comfort conditions. This is particularly true for healthcare facilities, where a comfortable environment can mean both a faster healing of the patients and a higher productivity rate of the employees. In this research, a comfort survey is carried out in two physiotherapy facilities in Bolzano, Italy. Long- and short-term measurements of air temperature and relative humidity and short-term measurements of mean radiant temperature, air velocity, illuminance, CO2 and CO concentrations are taken in the environments where the therapies are performed, from summer to autumn of the year 2018. The long-term conditions are monitored using HOBO sensors, with a 10-minute recording timestep, and installed approximately at the height of 1 m, to evaluate the conditions at the same level at which the therapies are performed. A Delta-Ohm HD32.1 microclimatic station with several probes is employed in similar positions for short term monitoring periods. During the whole survey, according to their availability, employees and patients are asked to assess thermal, light, acoustic comfort and air quality by means of questionnaires, developed starting from standards and previous works in literature. In details, anonymous questions are asked to collect data about personal conditions (sex, age, weight, height, clothing level, self-evaluation of the health status), comfort evaluations (seven points scale questions), type of detected discomfort issues (multiple-choice questions), date, time and room where the treatment is performed. Thanks to the data measured at the same times of the questionnaires’ answers, Fanger’s comfort indexes are calculated according to the technical standard EN ISO 7730 and compared with the real votes collected using the questionnaires. The results, together with a previous analysis made in Vienna in 2015, give good suggestions about the diagnosis of the indoor environmental quality and the control of the HVAC systems in this kind of facilities.
Influence of Carbon Dioxide Fluctuation and Thermal Environment on Workability, Physiology and Psychology
Authors: CHIKAMOTO Tomoyuki , MIMURA Ryouto
Published: August 2019

Although carbon dioxide (CO2) is a gas not perceived by human, extremely high concentration of CO2 has an influence on the human’s health. High concentration of CO2 also leads to lowering concentration ability and promoting drowsiness. It may also have an influence on productivity and learning efficiency of human. We conducted experiments to measure the amount of workability and the physiological and psychological response of the subjects. In the experiment, the concentration of CO2 was set at the constant level at each case. And then, the concentration of CO2 was changed to examine the physiological and psychological response. In the result of the experiment, the CO2 concentration had the influence on productivity and working efficiency of human. Even if the CO2 concentration is not so high, physiological condition of the human would be also affected.
Indoor monitoring of Scrovegni Chapel Crypt
Authors: Bison Paolo , Bortolin Alessandro , Cadelano Gianluca , Ferrarini Giovanni , Peron Fabio , Romagnoni Piercarlo , Stevan Antonio
Published: August 2019

The indoor microclimate of the Scrovegni Chapel in Padova (Italy) was analysed first in the ‘80s. The early study operates in the best way for what concerns the choice of measurement devices and their positioning. Starting from 1995 a Scientific-technical Board coordinates the various initiatives commissioned for the surveys of a conservation of the Scrovegni building structures and for the preservation of frescos. However only during the last ten years, the activities of the Board have been addressed also on the study of the hypogeal environments under the Chapel and in the external environment around it in order to prevent possible damage due to the presence of water which frequently submerges the floor and part of the vertical structures of the crypt (perimeter walls and brick partitions). The investigations have been therefore extended to the crypt. The present work reports the preliminary results of the cyclical survey campaign launched last year and still ongoing: passive thermographic techniques (non-invasive and non-destructive) have been used for the identification and the investigation of the relationship between the boundary seasonal thermohygrometric conditions and the rainfall variations and other exogenous phenomena related to the complex water system of the area on which the Scrovegni Chapel stands.