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This paper experimentally analyses an indoor environment assessment of a large group of respondents regarding their subjective perception of overall comfort, indoor air quality and humidity. The questionnaire survey was applied as a testing method together with measurements of the physical parameters conducted with a microclimate meter. Two types of environment were analysed: educational rooms and the climate chamber. The comparative analysis of the sensations experienced within them indicates that they generate quite similar responses; however, some discrepancies have been identified. The overall comfort of the climate chamber was typically assessed as being higher than that of the educational rooms at the same air temperature. The most favourable air temperature in the climate chamber was ca. 20.7 °C, while in the educational rooms it was ca. 22.3 °C. The most preferable conditions in the climate chamber occurred at a thermal sensation vote of −0.4 ("pleasantly slightly cool"), while in the educational rooms it occurred at +0.2 ("neutral/pleasantly slightly warm"). Quite strong correlations between overall comfort and indoor air quality as well as between humidity assessment and humidity preference votes were observed, which did not seem to depend on the type of environment. These findings are important because results from the simulated conditions are often used in the analyses of actual living/working environments. [ABSTRACT FROM AUTHOR]

People tend to spend considerable amounts of time in buildings; thus the issue of providing proper indoor environmental quality is of significant importance. This paper experimentally analyses the subjective sensations of the occupants of intelligent and traditional buildings with the focus on possible differences between these two types of buildings. The study is based on a large database of 1302 questionnaires collected in 92 rooms where simultaneous measurements of the indoor environment physical parameters (air and globe temperature, relative humidity, carbon dioxide concentration, and illuminance) were carried out. Their impact on the subjective assessment of the indoor environment has been presented and analysed. The results show that the occupants seemed to be more favourable towards the indoor conditions in the intelligent building; however, the differences in comparison to the traditional buildings were not considerable. Similarly, self-reported productivity proved to be higher in the intelligent building, while the optimal range of air temperature, which ensured highest productivity, was 22–25 °C. Moreover, a strong correlation between the occupants' overall comfort and their perception of the air quality has been found. [ABSTRACT FROM AUTHOR]

The aromatic odor of Plectranthus hadiensis var. tomentosus has been found to have the potential to improve physical and mental health of people in indoor environment, but its effectivess is reduced for that the release of volatile organic compounds from plants is susceptible to indoor environmental changes. The purpose of this study was to investigate the response of volatile organic compounds released by P. hadiensis var. tomentosus to common indoor environmental changes, and to provide a scientific basis for its efficient and sustainable application in building a comfortable pro-biotic environment to improve the physical and mental health of indoor personnel. Thus, the effects of four typical indoor environmental factors, such as air temperature, air relative humidity, CO2 concentration and light variation, on the release of volatile organic compounds from P. hadiensis var. tomentosus were investigated in this study. And the dynamic headspace and gas chromatography-mass spectrometry techniques were used to analyze the volatile organic compounds in different indoor environments with an environmental control device based on mixed-level orthogonal array design. The results were as follows:(1)Among the four typical indoor environmental factors of air temperature, air relative humidity, CO2 concentration and light condition, CO2 concentration and air temperature had greater effects on the release of volatile organic compounds from P. hadiensis var. tomentosus, while the effects of air relative humidity and light were weak.(2)For P. hadiensis var. tomentosus cultivated under normal photoperiod, an environmental condition with CO2 concentration of 500 μmol·mol-1, air temperature of 25 ℃ and air relative humidity of 60% was the most suitable for releasing volatile organic compounds from P. hadiensis var. tomentosus in the absence of light. Under this environmental condition, the total amount of volatile organic compounds released by P. hadiensis var. tomentosus was 86.23 μg·L-1·kg-1, and the content of biological active components with potentials for the positive intervention of physical and mental health was 78.03 μg·L-1·kg-1. In summary, the results suggest that when the aroma plant P. hadiensis var. tomentosus is used to build an indoor pro-biotic environment to maintain or improve the physical and mental health of people in indoor, the environmental conditions should be controlled properly, especially CO2 concentration and air temperature, so as to fully and efficiently produce the positive health benefits from P. hadiensis var. tomentosus. [ABSTRACT FROM AUTHOR]

In order to develop a fault detection and diagnosis (FDD) algorithm for air handling unit (AHU) based on machine learning, the economizer outdodor air temperature (OAT) sensor fault was modeled. Through EnergyPlus program, the economizer OAT sensor modeled a fault that measures the OAT that's higher or lower than the actual temperature. The distribution of abnormal node point air temperature produced by the fault at the control point of the economizer was reviewed. In addition, the relationship between OAT & mixed air temperature (MAT), OAT & outdoor air fraction (OAF), AHU cooling coil energy, and chiller energy were comparatively analyzed for each fault model. In the case of the fault models, although outdoor air suitable for cooling could be utilized during the operation, outdoor air was not introduced for cooling, and in the opposite case, outdoor air was introduced even when OAT was higher than the indoor set-point temperature, reducing the energy saving effect for cooling. In the future, we aim to analyze energy performance and indoor air quality according to the fault in the return air temperature (RAT) sensor and error in the opening position of the damper. In addition, we plan to continue the analysis of fault data for the various elements of an AHU, and develop FDD algorithms using machine learning. [ABSTRACT FROM AUTHOR]

This field study aimed to investigate naturally ventilated bedroom environment and its effects on subjective perception and sleep quality. Totally, 104 healthy subjects living in urban areas of Beijing participated in the study for one night during transition seasons. Bedroom environment parameters, including temperature, relative humidity, and CO2 concentration, were recorded before and during sleep. Objective sleep quality was measured by Fitbit Alta 2, a wrist‐type actigraphy sensor. Subjective assessments were collected by paper‐based questionnaires on sleep quality and environmental perceptions. The results showed that neutral temperature for waking state (before sleep) was estimated to be 23.8°C while for sleep state it was 26.5°C. Furthermore, pre‐sleep thermal sensation vote was found to be positively correlated with deep sleep percentage. Indoor air quality was correlated with sleep quality as indicated by statistically significant correlations between odor intensity assessment, air quality acceptability, average nightly CO2 concentration, and measures of sleep quality. For naturally ventilated bedrooms during transition seasons with a mild outdoor climate, present findings suggest that a bedroom with slightly warm pre‐sleep environment than neutral, and with high ventilation as indicated by low indoor CO2 concentration, could be beneficial for sleep quality of residents. [ABSTRACT FROM AUTHOR]

Many studies have been conducted to assess the effects of indoor air quality (IAQ) on human health. However, there is still a lack of studies available about the adverse health effects on children's respiratory health at Child Care Centers (CCC). The aim of this paper was to investigate the risk factors for respiratory symptoms and identify the root cause of IAQ problems at CCCs in Malaysia. The Modified American Thoracic Society and the Division of Lung Diseases (ATS-DLD-82) questionnaire was used to gather information from parents regarding their children's respiratory symptoms. The IAQ parameters measured were for air temperature, humidity, carbon dioxide, carbon monoxide, respirable particles (PM2.5), viable bacteria and fungi count while the information on CCC characteristics and potential surrounding air pollutants were collected via a combination of area monitoring, inspection and interviews. Factors found to be significantly associated with persistent cough and/or cold were age, type of ventilation, location of CCC, floor area per child (<3.5 m2) and temperature. Children attending CCCs supplied by ACMV had the highest risk for prevalence of persistent productive cough [5.56 (CI: 2.20; 14.00)]. This study provided the baseline data on IAQ and possible factors that influenced indoor air contaminants, which could aid policy makers in formulating guidelines on IAQ for CCC in Malaysia. [ABSTRACT FROM AUTHOR]

Propane heating is both a financial and an environmental burden for broiler houses located in cold climate regions. Heat recovery can reduce propane consumption significantly, by preheating fresh air inflow with stalled air outflow. While there have been many studies on the improvement of broiler houses direct ventilation, little attention has been given to the integration of heat exchangers. In this study, an existing broiler house (800 m2) equipped with two air-to-air ductless heat exchangers (0.38 m3s-1 each) was simulated. Computational fluid dynamics (CFD) software OpenFOAM was used to create a 3D steady-state buoyant simulation with RNG k - ε turbulence model. The CFD model was validated with experimental data from Nielsen (1976). In the reference configuration, the two heat exchangers were aligned in parallel, positioned against the northern wall. Three alternative heat exchangers configurations were simulated and analysed in their ability to provide adequate, uniform velocity, temperature and air age at bird height. No configuration was found to avoid excessive air velocities entirely. One configuration (C1) reduced the air age standard deviation from 477 to 179 s. It also increased the surface with adequate air quality from 55% (C0, reference case) to 72% of the floor area. Despite using the same heating power, temperature differences of up to 2 °C were observed in the mean air temperature of broiler zones of different configurations. These results confirm that ventilation performance can be improved by a careful analysis of heat exchangers position and its effects on airflow patterns. • Heat exchangers save fuel but achieving uniform housing conditions is a challenge. • One configuration (C1) reduced the air age standard deviation from 477 to 179 s. • Secondary vortex with low air quality can form with some configurations. • Excessive wind chill seems hard to eliminate with ductless heat exchangers. [ABSTRACT FROM AUTHOR]

Housing environment has become a driving factor on hen health, egg quality and efficient production in intensive poultry industry. In large layer poultry housing system, an environmental index is typically used to control air conditions, including air temperature (T), relative humidity (RH) and concentration of carbon dioxide (CO2) in different season. In hot seasons, thermal environment of laying hen housing is usually assessed using the temperature humidity index (THI) via the online monitored temperature and relative humidity. However, the simple assessment cannot meet the harsh requirement of indoor air quality in a large layer house, as the stocking density increases in recent years. In this paper, a comprehensive environmental index (CEI) was proposed based on the radar map to integrate the impacts of both thermal and air quality factors, in order to systematically assess the environment comfort of the birds. A LabVIEW software system was selected to illustrate the environmental comfort using the fuzzy mathematics. Five key environmental factors, including temperature, RH, air velocity, concentration of CO2 and ammonia (NH3), were used to evaluate the environmental comfort of laying hen housing, where the their weights were normalized in a radar map. In the visualized system, early warning can be delivered when either a single factor or the CEI was over the prescribed value, and thereby a quick action can be taken to adjust the environmental conditions in the layer housing to a comfort level. A field measurement was carried out at a commercial layer breeder farm in Hebei province from January to February, and from July to August, 2019. The experimental results indicated that a good performance of the CEI can be obtained to assess the comprehensive environment in the tested house via monitoring the five environmental indexes. The specific sensors were properly settled in the henhouse. The data of environmental conditions was collected to verify, and then the maximum of five indexes were selected for later use. During the summer daytime, the CEI agreed well with the THI, indicating the positive impacts of thermal environment on the comfort of the birds, while it performed better to integrate the thermal and air quality at night time. In winter, the increase in the weight of CO2 concentration can contribute to the CEI for the comfort in layer housing system. The in situ monitoring data in the actual use demonstrated that the CEI can efficiently represent the change of comprehensive environmental comfort in the chicken house, and respond to the interaction between environmental factors in each period, especially when the air quality has an increasing influence on the comprehensive environmental comfort at night in summer and in winter. The findings can provide a promising method to systematically evaluate the housing environment via the five key factors in laying hen housing, further to improve the birds comfort via precisely controlling the air conditions in intensive poultry production. [ABSTRACT FROM AUTHOR]

The object of this research study was to investigate the maximum effectiveness values of the energy wheel by experimental tests conducted under extreme difference ambient air conditions parameters, different air volume flow rates, and energy wheel rotation speeds. Air temperature and humidity experimental tests were performed using a test facility that was developed and installed into the Indoor Air Quality and Thermal Comfort Laboratory of Budapest University of Technology and Economics. Our objective was to get the effectiveness values of sorption coated air-to-air energy recovery wheel for steady-state conditions under different ambient air (as supply air inlet) conditions. It was found that the sensible effectiveness increases by decreasing the volumetric flow rate through the wheel, and the optimum values of the effectiveness were given at the maximum wheel rotation speed based on the tests. As for the latent and total effectivenesses, their characteristics show an increasing trend by decreasing the air volume flow rate, ambient air temperature and relative humidity and increasing the wheel rotation speed. [ABSTRACT FROM AUTHOR]

The use of an underfloor air distribution (UFAD) system integrated with a chilled ceiling (CC) cooling system can provide a potentially advanced heating, ventilation, and air conditioning (HVAC) system with high sensible cooling loads in modern office buildings. In this paper, an experimental study of the impact of CC in a room with a high sensible cooling load with UFAD was performed when the chilled ceiling surface temperature increased from 17.0 to 26.0 °C. The vertical distributions of indoor air temperature, air velocity, and pollutant (CO2) concentration were measured and evaluated by the vertical air temperature difference (VATD), turbulence intensity (TI), and contaminant removal effectiveness (CRE), respectively. The results showed that the average VATD, TI, and CRE were 0.1–0.9 °C, 4–40%, and 0.85–1.19, respectively, when the internal and external sensible cooling loads equal 41.5W/m2. These evaluation indices varied clearly when the internal sensible cooling load increased from 41.5 to 69.5W/m2, whereas they were almost the same when the external sensible cooling load increased from 41.5 to 69.5W/m2. The minimum CRE and air diffusion performance index (ADPI) coincided with the maximum heat removal effectiveness (HRE) under a constant cooling load condition. The results suggest that it is better to balance the energy consumption as well as indoor air quality and thermal comfort in a room with UFAD + CC. [ABSTRACT FROM AUTHOR]

Abstract Due to high power consumption and air pollution situation in China, insufficient indoor fresh air during heating season can be a noteworthy problem. Unlike previous researches, which mainly focused on cooling capacity of Earth-air Heat Exchanger (EAHE), feasibility of EAHE combined with Heat Recovery Unit (HRU) as an independent heat source to heat cold air in severe cold regions was firstly verified. U-shaped buried pipes were proposed to enhance heat transfer as well as save land-use. Thorough measurements of air and soil parameters and power consumption were conducted under several operation modes, performance indexes like heating capacity, heat transfer efficiency and COP were analyzed. Results showed average temperature rise of 14.0 °C provided by EAHE and further 12.1 °C promotion brought by HRU helped outdoor air reach to an acceptable level without auxiliary heating equipment. Heating capacity of EAHE increased with decreasing inlet temperature, when inlet temperature changed from −0.4 to −24.4 °C, heating capacity increased from 709 W (19.7 W/m) to 7718 W (214.4 W/m). Performance of HRU rarely reacted to climatic conditions because of the stable outlet temperature of EAHE. Maximum comprehensive COP was 16.3, which indicated the high efficiency of system. Results showed EAHE can be expanded to severe cold regions and achieve good efficiency. Highlights • Feasibility of applying Earth-air Heat Exchanger in severe cold regions was firstly investigated. • Experiments were conducted during heating season to evaluate the performance of system. • Correlation between heating capacity of EAHE and inlet air temperature was strong. • The proposed system can effectively heat fresh air without auxiliary heating equipment. • The influence to indoor environment brought by proposed system can be ignorable. [ABSTRACT FROM AUTHOR]

Indoor environmental conditions in intensive pig farms are influenced by both the outdoor air temperature and humidity, and the heat, moisture and gas exchanges between the animal and the air. As ventilation rate in pig facilities is usually estimated in temperature, moisture and even CO2 balances, estimation of heat losses or gains, and moisture and CO2 production from the animal is needed, but the contribution of other sources of the barn, such as slurry or wet surfaces have also to be taken into account. Some recent studies have been conducted to update total heat and moisture production at farm level, showing that current, historical standards of latent heat transfer are consistently lower than those reported recently at facility level, for both adult and growing animals. Also, CO2 production needs to be updated by including an estimation of its release from slurry. These new values will help with updating the standards for ventilation rate recommendations and design of the modern intensive pig buildings. [ABSTRACT FROM AUTHOR]

The heating and cooling of buildings with large-scale ceiling systems nowadays is widely used in traditional as well as in new, low-energy buildings. This type of system is being employed in a building of the Civil Engineering Faculty (FCE), Slovak Technical University, in Bratislava. The building's refurbishment in 2010 included the complete replacement of the building's envelope. The replacement is a lightweight facade with a high percentage of transparent construction. Due to the differences between the type of envelope and the heating system, the operation of the heating system frequently causes thermal discomfort, especially during warm spring or autumn days. The aim of the measurements was to evaluate the control of the operation of the heating output, the appropriateness of the location of sensors measuring the outdoor temperature and possible improvement of the current control system to improve the heating system's quality. [ABSTRACT FROM AUTHOR]

Heatwaves are known to result in negative health effects in general and especially in vulnerable populations. At the same time, the effect of high outdoor temperatures on indoor air quality is largely unknown. To start filling this knowledge gap, we recruited 24 seniors from 3 low-income housing sites in Elizabeth, NJ, to participate in a study, during which we deployed consumer-grade sensors in their apartments to monitor airborne particulate matter (PM 2.5) and air temperature. Additionally, one empty apartment, used as a control, and an outdoor station were set up with the same type of sensors. Measurements were performed from July to September 2017. During this period, there were seven days when outdoor temperatures exceeded 90 °F (32 °C), our criterion for heatwave days. First, we found that the average hourly indoor PM 2.5 levels varied among apartments and were greatly affected by the presence of smokers. During non-heatwave days, in apartments without smokers, the hourly median PM 2.5 concentrations ranged from 4 μg/m3 to 12 μg/m3, while in apartments with smokers, the hourly median PM 2.5 concentrations ranged from 14 μg/m3 to 90 μg/m3. More importantly, the indoor PM 2.5 levels were higher (p < 0.05) during heatwave days. A statistically significant increase was observed for all apartments, regardless of the building site, presence of smokers, or type of air conditioning. Moreover, since human activity contributes to indoor PM 2.5 , we separated the data into an active period (6:00 a.m. to 10:00 p.m.) and the rest period (10:00 p.m. to the next day 6:00 a.m.); the PM 2.5 increase during heatwaves was statistically significantly higher for both periods. Overall, our data suggest that higher ambient temperatures could be an important factor for indoor PM 2.5 exposures. Future investigations should consider several exposure-modifying factors, such as the use of windows and AC, for a more accurate assessment of outdoor conditions affecting indoor exposures. • Indoor PM 2.5 levels increased in 24 tested apartments during heatwaves. • Median hourly I/O PM 2.5 ratios in most apartments tended to decrease with heatwaves. • The presence of smoking had a negative effect on PM 2.5 levels during heatwaves and regular days. [ABSTRACT FROM AUTHOR]

The benefits of task ambient conditioning in improving thermal comfort and indoor air quality have been demonstrated in recent studies. The potential use of task ambient conditioning for improving thermal comfort when the room air temperature is beyond the suggested range in mixing ventilation; however, has not been fully explored. A newly developed task ambient conditioning with chest exposure was, therefore, suggested at the room air temperature of 28°C (82.4°F), which is higher than the normally set temperature under cooling conditions in mixing ventilation. The present study aims to explore the appropriate air parameter ranges of the local airflow, but not to develop the practical system. Assessments of the thermal environment were performed by subjective questionnaires under nine distinct conditions with task ambient conditioning with chest exposure as well as the ambient environment in a climate chamber. The thermal sensations under the nine conditions with task ambient conditioning with chest exposure were nearly thermal neutral or slightly cool, while a slightly warm sensation was experienced in an ambient environment. Thermal sensation votes indicated cooler sensations with a decrease in the temperature of the locally supplied air, and with an increase in the velocity of locally supplied air, as well as in the vent diameter. The locally supplied airflow of task ambient conditioning with chest exposure obviously improved thermal comfort, the percentage of discomfort was reduced to 20% or less. Furthermore, the appropriate ranges of airflow parameters (air temperature, air velocity, and vent diameter) of task ambient conditioning with chest exposure were demonstrated, to aid the practical development of task ambient conditioning with chest exposure systems. [ABSTRACT FROM PUBLISHER]

The object of this research was to investigate the effectiveness of sorption energy exchanger and the impact of the operational and thermal environmental conditions on their efficiency under steady-state conditions. To achieve this object, a test facility was installed into the Indoor Air Quality and Thermal Comfort Laboratory of BUTE University. A molecular 3Å sieve sorption wheel with high latent effectiveness is integrated into the experimental setup. In this study, the correlation between the sensible, latent, total effectiveness under different ambient air temperature and humidity values and different rotational speeds of the wheel is investigated in detailed by experimental tests. [ABSTRACT FROM AUTHOR]

The aim of this study was the development of a method to improve the effectiveness of heat treatment (HT) for insect pest control in flour mills by thermal analyses and temperature trend models. Specific attention was paid to surface temperatures of thermal bridges (TBs), which represent HT weakness points because they provide refuge to insects and increase expenditure of electric power due to heat flux loss. Air and TB surface temperatures were monitored in a flour mill during execution of an HT. A first thermal analysis showed that values of indoor air temperatures near TBs were always lower than the computed temperature level that would also guarantee insect mortality on TB surfaces. Since the length of the steady-state air temperature profile was lower than that lethal to all insect vital stages, time series forecasting models based on trend analyses were used to simulate the suitable HT duration. The results highlighted that HT should be increased by 9 h to achieve an air temperature above 45 °C. Finally, to obtain TB surface temperatures lethal to insects, simulations were performed of building interventions capable of reducing sensible heat flux loss through the TBs by using insulating materials. The method described in this paper could help operators define a more suitable HT length and support flour mill owners in decision-making when building interventions to improve heat capacity of the mill envelope should be considered to reduce the power consumption of HT. [ABSTRACT FROM AUTHOR]

Thermal environment in bedrooms is still a largely neglected topic in thermal comfort research, although a thermal comfortable environment is important for sleep maintenance. Studies confirm that human body is sensitive to air temperature during sleep; even moderate heat or cold exposure decrease sleep quality significantly. In the present paper we reviewed air temperatures measured in bedroom and the effects of heat and cold exposure on sleep quality, and then proposed 5 aspects of approaches or technologies that could improve sleeping thermal environment at a low energy consumption. We concluded that there are two important research topics in sleeping thermal environment. One is to develop sleeping-mode control strategy for air conditioner used in bedroom to get slight increase or to avoid decrease in room air temperature when approaching morning. The other is to control bed micro-environment energy efficiently by using of local heating, cooling and/or ventilation system. [ABSTRACT FROM AUTHOR]

Thermal sensation models, capable of predicting human's perception of thermal surroundings, are commonly used to assess given indoor conditions. These models differ in many aspects, such as the number and type of input conditions, the range of conditions in which the models can be applied, and the complexity of equations. Moreover, the models are associated with various thermal sensation scales. In this study, a systematic comparison of seven existing thermal sensation models has been performed with regard to exposures including various air temperatures, clothing thermal insulation, and metabolic rate values after a careful investigation of the models' range of applicability. Thermo-physiological data needed as input for some of the models were obtained from a mathematical model for human physiological responses. The comparison showed differences between models' predictions for the analyzed conditions, mostly higher than typical intersubject differences in votes. Therefore, it can be concluded that the choice of model strongly influences the assessment of indoor spaces. The issue of comparing different thermal sensation scales has also been discussed. [ABSTRACT FROM AUTHOR]

nEMoS (nano Environmental Monitoring System) is a 3D-printed device built following the Do-It-Yourself (DIY) approach. It can be connected to the web and it can be used to assess indoor environmental quality (IEQ). It is built using some low-cost sensors connected to an Arduino microcontroller board. The device is assembled in a small-sized case and both thermohygrometric sensors used to measure the air temperature and relative humidity, and the globe thermometer used to measure the radiant temperature, can be subject to thermal effects due to overheating of some nearby components. A thermographic analysis was made to rule out this possibility. The paper shows how the pervasive technique of additive manufacturing can be combined with the more traditional thermographic techniques to redesign the case and to verify the accuracy of the optimized system in order to prevent instrumental systematic errors in terms of the difference between experimental and actual values of the above-mentioned environmental parameters. [ABSTRACT FROM AUTHOR]

This paper presents the part of the research that has been done at the Universities both in Belgrade and Thessaloniki, Greece, taking into account indoor environmental quality in office buildings and classrooms. The measurements that are presented were done in Process Equipment Design Laboratory at Aristotle University Thessaloniki, during March 2015. Indoor environmental quality regarding air temperature, relative humidity, and CO2 concentration in two representative offices is observed. The similar offices are located one on the north-east and the other one on the south-west side of the University building, so as to be representative of the orientation's impact. Furthermore, the impact of natural ventilation on CO2 concentration and temperature is monitored, together with the offices ' occupancy. Recommended parameters for indoor air quality are compared and discussed on the base of several standards: SRPS EN 15251:2010, ASHRAE standards 55 and 62.1, and ISO 7730. The main objectives, as set from these standards are discussed, together with the investigation results. [ABSTRACT FROM AUTHOR]

The objective of this work was to propose a way of preparing information about in-cabin air quality for the car driver or passenger. It was assumed that information should be objective, relevant, current, complete and useful. The major elements of our concept were: (1) monitoring of selected air parameters inside the cabin, (2) determination of indicators that characterise indoor air, based on measurements, and (3) the method of information extraction. We proposed to realise the first task with a sensor system. The second and third goals were reached by categorisation. The basis for defining categories were ranges of values of measured parameters or their combinations. In a way, the categories were used to quantify indicators of air quality. Shannon entropy and mutual information were applied to find the best categorisation. The concept was investigated using experimental data from car cabin air monitoring in various driving conditions. We conclude that information about air quality in car cabins may be successfully conveyed using the following indicators: thermal conditions – determined based on temperature and relative humidity measurements; air exchange – determined based on CO 2 concentration; and air freshness – determined based on volatile organic compounds (VOCs) content in car cabin air. Each indicator has three categories: bad, intermediate and good. [ABSTRACT FROM AUTHOR]

The effect on humans of a 6-hour long exposure to cyclic fluctuating air temperature was examined. The tested fluctuating pattern consisted of a gradual sweep-up +2.0°C over 40 minutes and a rather abrupt sweep-down –2.0°C over 20 minutes, within the temperature ranges of 26–28°C and 27–29°C. The experiment on cyclic fluctuating air temperature demonstrates that the thermal dissatisfaction rate for cyclic fluctuating air temperature control between 26°C–28°C is lower than that for constant air temperature control at 26°C, while consuming less energy. Moreover, occupant stress levels measured by salivary alpha-amylase, and subjective fatigue levels under cyclic fluctuating air temperature show that similar or even lower distinct results can be achieved with fluctuating air temperature control compared with constant air temperature control. [ABSTRACT FROM AUTHOR]

Previous studies have shown that temperatures inside glazed balconies are almost without exception higher than those of outside air. This is due to the space's ability to capture and store the building's heat losses and solar radiation. The interior temperatures and energy saving effects of glazed balconies are, however, not particularly good in Finland, because the implemented solutions are not optimized for these issues. The purpose of this study is to introduce simplified evaluation methods for the energy saving and interior air temperature evaluation of glazed spaces and to verify the method reliably with the help of measured and simulated values of typical Finnish 1970s apartment blocks. The presented method can be used for optimizing and showing the energy saving impact as well as the mean, maximum and minimum temperatures of different type of glazed spaces in the preliminary design stage. The results show that the accuracy of the method is sufficient for designing if nine parameters are changed at most. The accuracy is affected by the number of changes made in relation to the typical 1970s apartment blocks in Finland, which was chosen as a starting point for the method's development. [ABSTRACT FROM AUTHOR]

Previous studies have shown that poorly ventilated classrooms can have negative impact on the health of children and school staff. In most cases, schools in Serbia are ventilated naturally. Considering their high occupancy, classroom air quality test determines the level of air pollution, after which it is possible to implement corrective measures. The research presented in this study, was conducted in four schools which are located in different areas and have different architecture designs. Measurements in these schools have been performed during the winter (heating season) and spring (non-heating season) and the following results were presented: indoor air temperature, relative humidity, and carbon dioxide concentration. These results show that the classroom average concentration of carbon dioxide often exceeds the value of 1500 ppm, during its full occupancy, which indicates inadequate ventilation. Measurement campaigns show that carbon dioxide concentration increased significantly from non-heating to heating season in three of the four schools. Analysis of measurements also determined high correlation between relative humidity and carbon dioxide concentration in all schools in winter season. This fact may constitute a solid basis for the fresh air supply strategy. [ABSTRACT FROM AUTHOR]

The variety of occupant behaviors in buildings have led to a significant mismatch between simulated building energy performance and measured one. It is crucial to collect real occupant behaviors in buildings to achieve accurate simulation purpose, although there exists a great challenge due to the cost of monitoring devices and privacy concerns. This study proposed an inexpensive and minimally intrusive method, to recognize behavior information from environment parameters by data mining approach. To validate this method, experiments were conducted in three bedrooms. Two types of classification algorithms were developed to recognize AC operations from the experiment data of indoor air temperature and relative humidity. Two types of recognition rules were generated from algorithm training in one dataset, and tested in the other datasets. Based on the testing results, the performance of the two algorithms were evaluated and compared. The results indicated that the C4.5 decision tree algorithm was not suitable for mining AC operations, while the curve description algorithm had good performance in processing the time-series curves of air temperature and relative humidity. Through this experiment, it is confirmed that AC operations can be recognized from indoor air temperature and relative humidity by data mining approach. The main contribution of this study is that a promising approach was developed, which is inexpensive and minimally intrusive on gathering and interpreting information about occupants’ daily behaviors. [ABSTRACT FROM AUTHOR]

Conventional chilled water based air conditioning systems use low temperature chilled water to remove both sensible load and latent load in conditioned space, and reheating devices are usually installed to warm the overcooled air, which leads to energy waste. Alternatively, this paper proposes a neural network (NN) model based predictive control strategy for simultaneous control of indoor air temperature and humidity by varying the speeds of compressor and supply air fan in a chilled water based air conditioning system. Firstly, a NN model has been developed to model the system dynamics, linking the variations of indoor air temperature and humidity with the variations of compressor speed and supply air fan speed. Subsequently, the NN model is experimentally validated and used as a predictor. Based on the NN model, a neural network predictive controller is proposed to control the indoor air temperature and humidity simultaneously. The experimental results demonstrate the effectiveness of the proposed scheme compared with conventional PID controllers. Moreover, it has been proven that it is practical to simultaneously control indoor air temperature and humidity by varying the compressor speed and the supply air fan speed without adding any other devices to the chilled water based air conditioning systems. [ABSTRACT FROM AUTHOR]

Indoor climate and energy performance of Finnish low energy office building were studied to determine optimal control and operation solutions of demand controlled room conditioning and ventilation system with airflow rate controlled active chilled beams. Onsite measured temperature, CO 2 , occupancy rate were used to calibrate a dynamic simulations model. The results showed an average occupancy rate of 0.55 during office hours (OH) offering a good energy saving potential for demand control ventilation (DCV) system. DCV system used 7–8% less total primary energy compared to constant air volume (CAV) system depending on control and operation strategy used. DCV system saving was 33–41% if only heating, cooling, fans and pumps primary energy were considered. Supply air temperature controlled according to extract air temperature instead of outdoor air temperature minimized overheating problem which occurred with design solution during both seasons and systems. DCV system with active chilled beam complied at least 94% and 90% of OH with Category II indoor climate with water priority cooling and air priority cooling control respectively. Ceiling cooling panel showed an effect of decoupling cooling from ventilation resulted only in 0.9% additional primary energy saving compared to DCV system with active chilled beams. [ABSTRACT FROM AUTHOR]

The aim of the study was to develop models for energy planning for an air supported sports hall by analyzing different energy efficiency possibilities. This is a very specific building type suitable for sport activities in cold climates. The observed hall was operated when outdoor temperature was under 5 °C, while the most common measured indoor air temperature was 8 °C during the year. Neither indoor nor outdoor temperature influenced the overpressure. Based on the measurements, the specific annually heating energy use was 75 kWh/m 2 . The results showed that improvement in the hall insulation would not give a significant effect on the heating use. The analysis of energy efficiency measures showed that air recirculation has the greatest effect on total energy use and the air recirculation could give an energy saving of 27% when 50% of the indoor air was recirculated. The results might be used to calculate heating energy demand for different operation scenarios in the air supported halls. The results give a simple tool to size the heating coil in the AHU and for energy planning for similar halls. The study gave very specific and unique data on energy use in sport halls in cold climate. [ABSTRACT FROM AUTHOR]

This study aims to investigate thermal environment and occupant local thermal sensation in offices with cooling ceiling. A field survey combining environment measurements and questionnaires was conducted in offices in Zhuhai, China. The obtained results indicated that compared with experimental conditions, occupants in real crowded offices experienced warmer environment because the mean radiant temperature (MRT) was higher than the air temperature due to the shelter effect of indoor furniture etc. MRT also showed higher correlations with both overall thermal sensation (OTS) and overall thermal comfort (OTC) than air temperature because a great part of heat transferred through radiation. Air temperature showed linear correlation with the ceiling temperature when cooling ceiling could fully handle the cooling load, but supplementary air cooling was also necessary for radiant cooling systems in real offices. Moreover, local thermal sensation (LTS) of different body parts showed great differences due to many factors such as clothes and adaptive behaviors, and it significantly influenced both OTS and OTC. Particularly, head, hand, leg and foot had considerable effects on OTS while head and leg showed influences on OTC. In addition, this paper also validated against some important results of previous studies and provided references for future work. [ABSTRACT FROM AUTHOR]

The aim of the present paper is to analyze a building optimization and control (BOC) algorithm which is implemented in the existing building energy management system (BEMS) of the Saint George Hospital in Chania, Greece. The developed algorithm consists of predicted models for outdoor/indoor air temperature using artificial neural networks, multi-step optimization using genetic algorithms and Real Time control using fuzzy techniques. The algorithm is developed in Matlab™ environment and is implemented to the existing BEMS of the Hospital, using a specialized web-based energy management and control system (Web-EMCS). The implementation of the BOC algorithm is realized by developing a “.net assembly” code, which interconnects the Web-EMCS with the existing conventional hospital's BEMS, without the need of Matlab™. The annual primary energy efficiency achieved is almost 36%. [ABSTRACT FROM AUTHOR]

One of the most important problems in studies of building environment is a description of how it is influenced by various dynamically changing factors. In this paper we characterized the joint impact of a collection of factors on indoor air quality (IAQ). We assumed that the influence is reflected in the temporal variability of IAQ parameters and may be deduced from it. The proposed method utilizes mean square displacement (MSD) analysis which was originally developed for studying the dynamics in various systems. Based on the MSD time-dependence descriptor β , we distinguished three types of the collective impact of factors on IAQ: retarding, stabilizing and promoting . We presented how the aggregated factors influence the temperature, relative humidity and CO 2 concentration, as these parameters are informative for the condition of indoor air. We discovered, that during a model day there are encountered one, two or even three types of influence. The presented method allows us to study the impacts from the perspective of the dynamics of indoor air. [ABSTRACT FROM AUTHOR]

Dew point temperature (DPT) of moist air plays a key role in ascertaining the comfort condition as well as indoor air quality for built environments. This article outlines a simple method to transform the fundamental relation between saturation pressure and temperature into a concise mathematical form for dew point temperatures of moist air that is applicable for normal comfort air conditioning systems. The error between the results from the derived equation and the ASHRAE correlation is found to be well within the accuracy limits of commonly used climatic sensors. Based on this equation, a simple computational method for wet bulb temperature (WBT) is proposed. The results from this method show minuscule error in comparison with the standard psychrometric data. Also, the DPT equation is used as a basis for plotting wet sensible and latent loads of a cooling dehumidifying coil by applying both temperature and humidity discretization schemes. Application of the inherently simple and aptly accurate DPT equation results in the representation of subtle variations in coil loads at varying psychrometric parameters of moist air, to be conclusive and theoretically conformal. [ABSTRACT FROM AUTHOR]

In this paper is presented methodological approach to the energy efficiency optimization of high density data centre, in a synergy with relevant performance analysis of corresponding case study. Related case study goal—to optimize energy efficiency to the level characterized by the power usage effectiveness nearly equal 1 (PUE ≈ 1), has been successfully realized, tracing an energy efficiency optimization road to a hyper energy efficient data centre of the superb IT and energy performance. In addition to the corresponding energy densities, and energy efficient removal of extremely high heat dissipation, to reach superb IT performance very special focus is to be devoted to finally controlling indoor air temperature and humidity conditions. It has been shown that, by an integrated approach to the optimization of building construction, data centre's intrinsic IT systems and equipment selection is to be done also with the reference to its specific energy efficiency and the most recent breakthroughs in IT infrastructure fields, as well as in data centre's high performance air-conditioning and infrastructure's high precision cooling. Finally, data centre greening, implementing renewable energy sources has been analysed. [ABSTRACT FROM AUTHOR]

The control systems of conventional heat pumps have an input of refrigerant temperature at the evaporator outlet to maintain superheat at proper level. In order to develop a control method that can be used to achieve better indoor thermal comfort and energy efficiency at a low cooling load condition than the current control method, a new method of the evaporation pressure control based on the evaporator outlet pressure reading (EPCP) was developed. The changes in the stability of indoor air temperature and power consumption were measured while changing the compressor frequency in accordance with the new control method. Compared with the evaporation pressure control based on the evaporator outlet temperature reading, the EPCP control method appeared to improve the stability of room air temperature or occupant thermal comfort significantly. [ABSTRACT FROM AUTHOR]

A key element for a reduced energy usage in the building sector is to improve the systems for indoor climate control. But, it is important that such measures are fairly simple and easy to implement in order to facilitate a widespread utilization. In this work, four alternative strategies for supply air temperature control in offices were investigated through simulations. Their level of complexity stretches from linear SISO (single-input, single-output) structures with standard inputs to an optimal algorithm with information about the entire set of disturbances acting on the building. The study was conducted with a conventional outdoor-air-temperature based method as benchmark, and two different heating, ventilation and air-conditioning (HVAC) systems as well as two types of building structures were taken into account. Compared to the benchmark, all alternative strategies resulted in lower energy usages while thermal comfort and indoor air quality were satisfied, and simple strategies could perform almost equally well as more complex. But, it was also shown that the benefits were highly dependent on the considered HVAC system and somewhat dependent on the considered building structures. [ABSTRACT FROM AUTHOR]

Both earth-tube systems and building thermal mass have the potential to provide desired performance levels for both indoor thermal comfort and energy saving; however, their coupling effects need to be further investigated. A model for evaluation of the combined effects of earth-tube ventilation systems and building thermal mass is proposed. Both the time-averaged indoor air temperatures and periodic temperature fluctuations are given as explicit formulas. Unlike the time lag induced by the separate use of building thermal mass, which is no longer than 6 h, the combination with an earth-tube system could extend the time lag of indoor air temperature in an annual fluctuation period by tens of days and that of a daily period by a couple of hours. It is noticeable that the building thermal mass has significant impact on the effectiveness of earth-tube systems; therefore, a small heat transfer coefficient of external envelopes helps increase the annual time lag of indoor air temperature. Using a proper combination of building thermal mass and earth tubes, indoor thermal comfort can be achieved for a building located in a region with both hot summers and cold winters without any additional cooling or heating load. [ABSTRACT FROM AUTHOR]

Night ventilation may improve the indoor air temperature and reduce the cooling load. However, the effects of different night ventilation rates on the indoor air relative humidity, wall inner surface temperature, inner surface moisture flux, sensible heat load, latent heat load and total load are rarely studied in terms of the inner surface moisture transfer. The present paper aims to investigate the effect of different night ventilation rates on the above items in a hot-humid climate in China. The results show the following: when the moisture absorption–desorption process at the wall inner surface is not considered, the air-conditioning load of the night ventilation at 15ACH is approximately 5% lower than that at 5ACH. When the moisture absorption–desorption process is considered, the night ventilation rate has a smaller impact on the indoor air temperature and has a larger impact on the indoor air relative humidity during the night. The night ventilation rate negatively correlates with the sensible heat load and positively correlates with the latent heat load due to the increased amount of moisture that is absorbed or desorbed at the interior wall surface. The total air-conditioning load of Case B.1, which featured a 15ACH night ventilation rate, was approximately 8% higher than that of Case A.1, which featured a 5ACH night ventilation rate. [ABSTRACT FROM AUTHOR]

• A prediction method (PredicTAIL) was developed to assess the IEQ in buildings. • The PredicTAIL method predicts the changes in IEQ due to deep energy renovation. • The PredicTAIL method was validated using measurement results from two buildings. • The sensitivity of the PredicTAIL method was verified by four simulation scenarios. • Energy renovation can improve or degrade a building's IEQ depending on the strategy. The recently developed TAIL rating scheme enables assessment of the changes in the indoor environmental quality (IEQ) associated with a building's deep energy renovation (DER) and classification of the resulting quality levels of the thermal (T), acoustic (A), and luminous (visual) (L) environments and indoor air quality (I). Since the TAIL rating is primarily based on measurements, it cannot be determined prior to renovation operations to help design the IEQ. To fill this gap, the PredicTAIL method was developed in the present study to predict the changes in ten of the twelve TAIL parameters as a result of DER. These parameters are indoor air temperature, relative humidity, sound pressure level, daylight factor, illuminance, and concentrations of carbon dioxide, formaldehyde, benzene, radon, and PM 2.5 ; no prediction is made for ventilation rate or mold. To examine the feasibility of the PredicTAIL method and the sensitivity of the existing models for quantifying changes in the TAIL parameters corresponding to different renovation strategies, simulations were performed in a hotel and an office building using TRNSYS, IDA ICE, ACOUBAT, MATHIS-QAI, and PHANIE. These modeling tools were first benchmarked against the TAIL parameters measured in the buildings before renovation. Once the agreement between measurements and modeling was considered acceptable, four pragmatic renovation scenarios were applied, and their impact on the IEQ parameters was quantitatively modeled. The simulations showed that the quality levels of the IEQ parameters were improved or unchanged for some parameters but degraded for other parameters after DER. The changes in the IEQ parameters and the TAIL rating depended on the renovation scenarios, suggesting that the PredicTAIL method is sufficiently sensitive to guide renovation design. [ABSTRACT FROM AUTHOR]

Abstract: Nowadays people are excessively depending on air conditioning to create a comfortable indoor environment, but it could cause some health problems in a long run. In this paper, wind velocity field, temperature field and air age field in a bedroom with wall-hanging air conditioning running in summer are analyzed by CFD numerical simulation technology. The results show that wall-hanging air conditioning system can undertake indoor heat load and conduct good indoor thermal comfort. In terms of wind velocity, air speed in activity area where people sit and stand is moderate, most of which cannot feel wind flow and meet the summer indoor wind comfort requirement. However, for air quality, there are local areas without ventilation and toxic gases not discharged in time. Therefore it is necessary to take effective measures to improve air quality. Compared with the traditional measurement method, CFD software has many advantages in simulating indoor environment, so it is hopeful for humans to create a more comfortable, healthy living environment by CFD in the future. [Copyright &y& Elsevier]

Highlights: [•] Convective strengths prevail with respect to the direction imposed on the air inlet. [•] Changes in age of the air depend on the flow pattern established by the temperatures. [•] The interchange of the energy causes the room average age not to change significantly. [•] CFD tools are very useful for the study of the airflows in rooms. [ABSTRACT FROM AUTHOR]

Highlights: [•] A new type of PCM room is proposed, two kinds of PCM were used in the room. [•] The new room can decrease the indoor air temperature fluctuation by 4.3°C in summer. [•] Indoor air temperature fluctuation was decreased by 14.2°C in winter for the new room. [•] Important factors that affect the thermal performance of the new room were studied. [ABSTRACT FROM AUTHOR]