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The energy consumption of air conditioning system accounts for a significant proportion of the total energy consumed in data center. To reduce the energy consumption of the cooling system, an integrated system, which combines pumped refrigerant two-phase cycle (PRTC) with vapor compression cycle (VCC), is proposed in this paper. The impacts of input frequency and outdoor air temperature on the performances of PRTC, and that of the outdoor air temperature on the performances of VCC have been investigated. It was found that PRTC had higher EER than VCC, but its cooling capacity was limited by outdoor air temperature. In PRTC, the designed cooling capacity of 2500 W could be obtained when the outdoor air temperature was −3.0 °C. In addition, 80% and 50% of the designed cooling capacity can be obtained at ambient temperatures 3.2 °C and 12.0 °C, respectively. Besides, the feasibility of the system in different climate zones in China was demonstrated by analysis of the climate data in Harbin, Beijing, Wuhan, Guangzhou and Guiyang, respectively. Results indicated the proposed system had high feasibility in Harbin and Beijing. The results of this paper can provide valuable insights into the cooling system driven by both liquid refrigerant pump (LRP) and vapor compressor, targeting at reducing the cooling energy consumption and maximizing the economic efficiency of the cooling system in data center. [ABSTRACT FROM AUTHOR]

A sleeping person is naturally immobile in a relatively small space. Hence, task\ambient air conditioning (TAC) can be best applied to a sleeping environment because of its proven performances in energy saving. However, when using previously developed the TAC systems for sleeping environment applications, cold draft was a serious issue and could hardly be avoided due to a high air velocity and a low air temperature inside an occupied zone. Therefore, in the experimental study reported in this paper, a radiation-based TAC (R-TAC) system has been developed, and its performances experimentally evaluated. In this paper, firstly, an experimental setup for a prototype R-TAC system, and experimental conditions and methods are reported. This is followed by presenting experimental results on the thermal comfort and ventilation performance. Finally, the issues of condensation risk when using the proposed R-TAC system are discussed. The study results presented in this paper have shown that the use of the R-TAC system could not only result in better thermal comfort and ventilation performances, but also effectively resolve the cold draft problem. In addition, the potential problem of potential condensation on a surface may be resolved by raising the panel surface temperature, or using a lower fresh air supply humidity. [ABSTRACT FROM AUTHOR]

• Experiment in three homes using mixed-methods and physical measurements. • Indoor air temperature fluctuations like those of EMPC of space heating. • Night setback-users found the heating control unacceptable. • Acceptance was motivated by economic or environmental benefits. Recent simulation-based studies have indicated that Economic Model Predictive Control (EMPC) of space heating systems can exploit the thermal mass in residential buildings for demand response (DR) purposes in district heating systems. However, there is a lack of studies on residents' perception and acceptance of the fluctuating indoor air temperature behaviour inherent in EMPC of space heating. This paper reports on a case study featuring the residents of three one-story houses located in Denmark. The houses were equipped with technology enabling remote actuation of radiator thermostats and collection of various indoor environmental data. Four different temperature boost interventions mimicking the typical behaviour of EMPC of radiators were executed while a mixed-methods triangulation design, employing questionnaires and semi-structured interviews, was used to collect subjective data. Data showed that residents accepted the behaviour but only after the benefits of the EMPC were explained. The acceptance was motivated by either the prospect of saving money, environmental benefits, or a combination of both. The results thereby indicate that explaining the benefits of EMPC is important if residents are to abandon their current preferences and practices in favour of an EMPC concept. The explanation should consider the diversity in current preferences, expectations, and level of technological pre-knowledge. In addition, the paper also reports on a range of findings related to technical aspects of realising EMPC in practice. [ABSTRACT FROM AUTHOR]

In buildings, occupant behaviour is recognised as a major contributing factor to energy demand and in particular to heating consumption. To achieve thermal comfort within the heating season, people report to use heat in very different ways; for example behaviours include switching on the heating system, putting on warm clothes, drawing curtains, changing rooms, making a hot drink and using a hot water bottle. While research has focused on subjective accounts using interviews, diaries and questionnaires, little is known about the frequency and probability of these behaviours. Using a mixed-method approach, this paper reports on the results of a field study in dwellings using wearable and environmental sensors. The analysis investigates the probability of these behavioural responses as a function of seven independent variables; (1) external and (2) internal monitored temperature, (3) probability of heating being on or off, (4) time of the week, (5) time of the day, (6) the three categories of the predictive thermal comfort model, and (7) the three categories of the adaptive thermal comfort model. Results show that participants were more likely to increase their clothing and activity level as internal temperature decreased, although there was no significant change in activity level throughout the course of a day. Methodologically, this paper demonstrates the effectiveness of different statistical tools in analysing occupants’ behaviours. Substantively, this paper emphasises the need for future research to gather objective data on what people do. [ABSTRACT FROM AUTHOR]

The goal of this paper is to identify the effects of in-pore transport of liquid water and water vapor as well as phase changes on the hygrothermal behavior of earthen buildings. Indeed, one of the main assets used to promote these constructions is their role in moisture buffering hence temperature and relative-humidity quality controlling. However, there is no clear consensus yet concerning the impact of these phenomena on the global energy performance of the buildings. A coupled model is therefore proposed in this paper, based on heat and mass balances inside the earthen walls, in order to clarify this question. This model considers separately the kinematics of each phase (e.g. liquid water, vapor, dry air and solid matrix), in interaction with each other. It also takes into account the impact of pore water confinement on the liquid-to-vapor phase change, in particular on the resulting latent heat released or absorbed. The model is successfully compared to experimental results on instrumented full-scale rammed earth wall subjected to temperature cycles. It eventually allows identifying the singular hygrothermal behavior of earth material by testing the range of applicability of the simplifying assumptions which are commonly made in function of the permeability of the tested material. [ABSTRACT FROM AUTHOR]

Improving the performance of air-to-air heat recovery systems, as measured by supply air temperature efficiency, is an important energy saving strategy that is often regulated by building codes. The high nonlinearity of supply air temperature efficiency with airflow rate in a run-around heat recovery system makes the trend prediction of supply air temperature efficiency especially challenging for field measurement. This paper proposes a simple and novel field measurement based methodology, supported by the power law relationship of air-side heat transfer, to evaluate the performance of run-around heat recovery systems. A system dependent power, signature power , is proposed that establishes a linear relationship between the supply air temperature increment across the supply air heat exchanger and a parameter—the maximum temperature difference between exhaust and supply airstreams divided by the signature power of the supply airflow rate. This methodology can predict the supply air temperature efficiency and is verified using four run-around heat recovery systems with field measurements. This new methodology can possibly be applied to other types of air-to-air heat recovery systems. This paper also describes a tuning method for determining the signature power based on field measurements and addresses the heat recovery efficiency of run-around heat recovery systems. [ABSTRACT FROM AUTHOR]

This paper is focused on increasing the knowledge on methods for calibrating BES models and to get more insights of different approaches for the optimization of the calibration process. The paper will be centred in the evaluation of a multistage guided search approach. It defines an iterative optimization procedure which starts with the assignment of probabilistic density functions to the unknown parameters, followed by a random sampling and running batch of simulations. It then finishes with an iterative uncertainty and sensitivity analysis combined with a re-assignment of the ranges of variation of the strong parameters. The procedure converges when no new influencing parameters are found. This method is applied to a real case study consisting of an unoccupied office building located in Lleida (Spain). The measured indoor temperature has been used to determine the uncertainty and precision of the method. The effect of the size of the sampling, the number of iterations and the parameters of the global sensitivity method are analyzed in detail. The results of this paper exemplify the degree of accuracy of multistage guided search approaches, and illustrate the reasons how these analyses can contribute to the improvement of more refined calibration methods. [ABSTRACT FROM AUTHOR]

Several studies have indicated that Economic Model Predictive Control (EMPC) of residential space heating systems can exploit the building thermal mass to provide demand response for the energy supply system by boosting the indoor air temperature prior to peak load periods. The practical uptake of EMPC is thus dependent on whether residents accept the fluctuating indoor air temperatures induced by this form of EMPC. Evidence on this aspect is scarce but a few studies indicate in hindsight that it might be important to explain the economic and environmental benefits of an EMPC if residents are to abandon their current preferences and practices in favour of an EMPC concept. The objective of the study reported in this paper was therefore to investigate whether residents of three single-family homes actually would accept the fluctuating indoor air temperature induced by EMPC when being aware of environmental and/or economic benefits. The results suggest that residents are willing to accept the fluctuating indoor air temperature being aware of economic and environmental benefits – as long as the fluctuations do not make them feel too cold. [ABSTRACT FROM AUTHOR]

• The average monthly daytime gap temperatures were always lower than ambient air (up to 4 °C). • During warm months, evapotranspirative cooling contributed 55% of the total gap cooling. • During winter days, external wall warming was observed behind the north-facing deciduous green façade. • simple linear correlations were found between ambient air and gap temperatures (R2 > 0.80). • The linear correlation between ambient air and gap temperatures was also predicted previously published gap temperatures very well (R2 0.98) The growing interest in energy savings and environmental sustainability in buildings has led to green buildings and green façades being considered as innovative solutions. This paper aimed to quantify the impact of ambient air temperature, orientation (west and north) and climbing plant status and type (leaf area index, percent coverage, deciduous and non-deciduous) on the thermal performance of green façades including external wall and gap cooling/warming effects. Temperatures of biological façades (i.e. green façade) and non-biological façades (i.e. shade sail) were monitored over 12 months in Perth, Western Australia, under a Mediterranean climate. Air temperatures within the gaps between the façade and external walls were also monitored. The average monthly daytime gap temperatures behind the green façades were always lower than ambient air and those behind the shade sails (up to 4 °C). The orientation of the façade relative to solar angle controlled the duration of solar irradiance; seasonal variations were observed in the relative contribution of evapotranspirative cooling to overall gap cooling, even in non-deciduous green façades. Despite the complex relationships between evapotranspirative cooling and a range of ecophysiological and micro-climate parameters, simple linear correlations were found between ambient air and gap temperatures (R2 > 0.8). This emphasizes the dominance of ambient air temperature in controlling the thermal performance of green facades. This thermal performance assessment and the gap temperature simulation can help urban designers, architects, and environmental engineers improve building and façade design to reduce energy consumption and greenhouse emissions. [ABSTRACT FROM AUTHOR]

• Statistical analysis of the performance of a green wall in a Mediterranean climate. • Irradiance is discarded as a variable affecting the adjacent temperatures reduction. • Maximum reduction of 0.63 °C in summer and 0.54 °C in winter at 1 m from the south facade. • Maximum reduction of 2.3% HR in winter at 1 m from the south façade. • Reduction average of 0.9% HR in summer at 1 m from the south façade. A study has been performed to quantify the impact of a green wall temperature reduction in a continental Mediterranean climate. This paper presents the results of a monitoring campaign during the summer and winter of 2021–2022. First, a database was elaborated with information on air temperature and relative humidity at four different distances from the wall (0.25, 0.50, 0.75, and 1 m) and irradiance in the vertical plane. Secondly, a statistical analysis was carried out to determine whether there is a correlation between these variables and whether there are statistically significant differences between them at different distances from the wall. Results show a strong positive correlation between air temperature recorded by sensors and the ambient air temperature for all seasons and between air temperature and relative humidity in summer. The ANOVA shows that the green wall reduces the temperature and relative humidity with statistical significance for most of the cases. These results confirmed the great capacity of green walls to improve the urban microclimate, especially during summer, by reducing air temperatures, providing evidence that greening the building envelope can complement conventional city green infrastructure and provide multiple ecosystem services to dense urban contexts. [ABSTRACT FROM AUTHOR]

This paper aims to explore gender differences in thermal comfort under coupled environmental factors, as previous studies have primarily focused on air temperature alone. The experiment involved 27 subjects, 13 males and 14 females, who experienced 12 different combinations of air temperature and air velocity environmental conditions. The subjective responses and physiological parameters were collected and analyzed. In colder environments, especially when low air temperatures are coupled with elevated air velocity, significant gender differences are observed, as females feel colder, more uncomfortable, and perceive stronger drafts than males. In hotter environments, when high air temperatures are coupled with still air, males tend to feel more uncomfortable and prefer higher air velocity, compared to females. However, few gender differences are observed when high air temperatures are coupled with elevated air velocity. Under colder conditions, forearm temperatures show a stronger correlation with subjective responses, while under hotter conditions, facial skin temperatures demonstrate a stronger correlation, for both genders. Moreover, the Elevated Air Speed Model in ASHRAE 55–2020 is found to overestimates the cooling effect of elevated air velocity for both genders. The findings suggest that gender differences should be properly considered when designing indoor thermal environments, particularly under colder conditions. [ABSTRACT FROM AUTHOR]

In the era of post-Coronavirus Disease 2019, the dedicated outdoor air system (DOAS), which provides 100% outdoor air for the building, is widely acknowledged as it can ensure acceptable indoor air quality by delivering fresh outdoor air to occupied space. The DOAS with a proper design and operation can provide sufficient ventilation and dehumidification while achieving energy efficiency. Nonetheless, there is limited guidance in determining the optimal control sequence of the DOAS for the designers and operators to implement in practice. Accordingly, in practice, a number of issues have been acknowledged in the design and control phases of DOAS, including insufficient ventilation and dehumidification, and increasing supply air dry-bulb temperature in fear of over-cooling, which might cause significant discomfort and energy waste. There have been efforts to develop high-performing DOAS controls for better energy efficiency. However, such controls are often complex, or difficult to interpret, for building designers and operators to consider in practice. In this regard, this paper explores a simulation-based framework for generating a supply air temperature control sequence of the DOAS not only to ensure improved energy-saving potential but also to guarantee the implement-ability of the control logic. The U.S. Department of Energy prototype primary school with dynamic occupancy profiles was modeled with a whole building simulation program, EnergyPlus. The model consists of a DOAS with an exhaust air energy recovery system for ventilation and fan-coil units for space cooling and heating. Then, a Genetic Algorithm was adopted to find the true optimal supply air temperature control sequence in terms of minimizing the energy cost of the heating, ventilation, and air conditioning system operation. Lastly, Decision Tree was adopted to extract rules out of the optimums to derive an implementable sequence of operation for the DOAS supply air temperature. A total of 12 week-simulation including four weeks of heating, cooling, and shoulder seasons, separately, under the weather condition of New York City was conducted for the case study. This case study identified that the optimization-informed rule extraction-based control, when compared to conventional outdoor air temperature-based reset control, could save about 13% of energy cost and 25% of energy consumption throughout the heating, cooling, and shoulder seasons. It is notable that the energy-saving was mainly achieved by reducing the heating energy consumption. Importantly, it nearly corresponds to the true optimal control result, which reduces approximately 14% of energy cost and 27% of energy consumption. From the results, it can be highlighted that the optimization-informed rule extraction can be as energy effective as the optimal control, while significantly reducing the complexity of the control. [ABSTRACT FROM AUTHOR]

Abstract: In the last years many studies concerning the evaluation of the thermal conductance of building elements via measurements have been carried out; this value has to be ensued from the analysis of recorded temperature and heat flux profiles. The determination of this property in situ would allow a more accurate a more accurate evaluation of the real heating energy demand of a building. Papers discussing different data analysis methods are present in literature and measurements on test components under real conditions and evaluations on different theoretical aspects by means of numerical simulations have been already developed. This paper aims at widening the existent literature of the in situ evaluation of the thermal conductance, through the discussion of the results of a measuring campaign which lasted four years on real buildings, and by comparing the reference specific thermal conductance (C) values with those computed on the basis of the measurements. Various tests on the same elements are discussed. Finally an analysis on the influence of the C value on the evaluation of the net heating energy demand of a building in different climates is presented. [Copyright &y& Elsevier]

Abstract: Reducing the energy consumption of air-conditioning systems is becoming increasingly important. This paper focuses on the air-conditioning system in Terminal 3 in Xi’an Xianyang International Airport, the first airport terminal to adopt radiant cooling in China. In the large spaces of this airport terminal, a temperature and humidity independent control (THIC) system has been adopted instead of a conventional nozzle air supply method, which significantly reduces the energy consumption of the air supply. The radiant floor is the main mechanism for indoor temperature control, while a liquid desiccant outdoor air processor combined with displacement ventilation is responsible for humidity control. Ice storage is adopted to reduce operating costs, and the supplied chilled water temperature can be as low as 3°C. This paper examines the performance of the THIC system in detail. The indoor environment is determined through measurements to be comfortable, and the on-site performances of key components in both the airport terminal and the cooling plant are investigated. The outdoor air processor supplies air of appropriate temperature and humidity ratio; two kinds of radiant floors are used for temperature control, both with measured cooling capacities of about 30–40W/m2; and the energy efficiency ratio (EER) of the cooling plant is 2.62. [Copyright &y& Elsevier]

Abstract: The adaptive approach to thermal comfort has gained unprecedented exposure and rising status recently among the thermal comfort community at the apparent expense of the heat balance approach for the evaluation of naturally ventilated buildings. The main appeal of this adaptive approach lies in its simplicity whereby the comfort temperature is expressed as a function of the outdoor air temperature only. The main responsibility for attaining thermal comfort is given to the individual, who is supposed to have some degree of control over the personal thermal environment. The adjustment of expectation enables a wider comfort temperature range in which occupants feel comfortable. Arguments in favor of the adaptive approach have been based on the results from a large number of field studies conducted across the globe involving the occupants of various types of buildings. It is not surprising, therefore, to watch proliferation of papers on the adaptive approach in the scientific domain and the incorporation of adaptive findings into standards and guidelines. However, there are a number of issues in the advancement of this approach, which have had little exposure in the literature. This paper looks critically at the foundation and underlying assumptions of the adaptive model approach and its findings. [Copyright &y& Elsevier]

Highlights • A modern house with diverse spaces was investigated. • Spatial configuration, microclimate and thermal comfort were studied. • The spatial configuration provides a good building microclimate. • The spatial configuration provides the possibility for occupants' adaptive actions. • Considerable summer thermal comfort can be achieved in the microclimate. Abstract In this paper, the authors attempt to clarify the relationship between spatial configuration, building microclimate and thermal comfort through the investigation of a modern house in hot and humid climate with spatial diversity. Firstly, the spatial configuration of the house was analysed in detail. The spatial geometric features, spatial boundary conditions, and human activities in the building were categorised. Secondly, field measurements were conducted to investigate the microclimate of the house. The air temperature, relative humidity and wind velocity were monitored on typical summer days. Thirdly, a dynamic thermal simulation was performed to predict the thermal comfort performance of the building over the period of an entire summer. The simulated results were compared with the measurements, and the adaptive thermal comfort approach was used to evaluate the thermal comfort. The modern house studied was found to have a varied spatial configuration, similar to local vernacular buildings, which produces diverse thermal environments in the building. The microclimate of this specific building could provide considerable thermal comfort for the occupants in summer under the local climate conditions, although thermal comfort cannot be achieved through free-running model in the hottest days, mechanical cooling or mixed model are needed. [ABSTRACT FROM AUTHOR]

Abstract In this paper, the energy performance of a photovoltaic/thermal collector equipped with a direct PV air circulation device is studied experimentally and numerically. In this system, the air circulation through the collector duct is ensured by a low input power DC fan that is directly connected to a PV module of small power capacity. In fact, depending on which period of the year the PV/thermal collector is being employed, a 4 Wp or 12 Wp PV panel is used to supply the electrical power to run the DC fan respectively for cold/winter or hot/summer periods. Therefore, the air flow rate under which the present hybrid collector operates is variable and highly affected by the incident solar radiation intensity. A theoretical model for the present hybrid system, in which air flow rate is introduced as a simple empirical correlation relating flow rate to solar radiation, was developed and obtained numerical results have been validated by experimental ones. Simulation and experimental results have been found in reasonably good agreement in terms of PV cell temperature, outlet air temperature, and electric PV peak power. Moreover, the obtained results revealed that low flow rate PV-assisted air circulation systems, if properly sized, would be very attractive for cold periods and winter conditions because of the high air temperature difference they could produce which is a key parameter for space heating applications. On the other hand, the high flow rate system seems to be very suitable for summer conditions where priority is given for the ventilation of PV modules to lower their cells temperature. The suggested PV/T collector design offers the advantage to be self-energy dependent and seems to have a great potential in remote areas. [ABSTRACT FROM AUTHOR]

Highlights • A nominal output capacity based performance index for ASHPs, ɛ NL , was proposed. • ɛ NL was influenced by ambient air conditions and defrosting initiating time. • A four-layer GRNN model for predicting ɛ NL was developed. • ɛ NL at varying operating conditions was predicted using the GRNN model. Abstract Air source heat pump (ASHP) units have been widely used for space heating in recent years. While a space heating ASHP unit is normally rated at its nominal operating condition, however, during its actual space heating operation, it rarely works at the nominal condition. The actual output heating capacity can remarkably deviate from that at the nominal condition, due to the influences of ambient air temperature and frosting-defrosting operation. Therefore, to enable a comprehensive and convenient evaluation of the operating performance of ASHP units with frosting-defrosting operation and to provide designers with appropriate design guidelines to size a space heating ASHP unit, a new performance index has been proposed. The new performance index, ɛ NL , or the loss coefficient in the nominal output heating energy, was actually based on the nominal output heating capacity of ASHP units, which was readily available and stayed unchanged irrespective when and where ASHP units were operated. In this paper, the definition of ɛ NL was firstly given, following a detailed explanation of the frosting-defrosting operation of an ASHP unit. Secondly, a GRNN model for predicting the ɛ NL of a field ASHP unit was established following a correlation analysis using a total of 473 groups of field measured data from the field ASHP unit. Finally, a modeling study using the developed GRNN model was carried out, and the study results suggested that when an ASHP unit was operated at a fixed ambient condition, defrosting initiating time would affect the ɛ NL , and there may exist an optimal defrosting initiating time at which ɛ NL was at its minimum. The model results also demonstrated that an increase in ambient air relative humidity or a decrease in ambient air temperature would result in an increase in ɛ NL , when an ASHP unit was operated with a fixed defrosting initiating time. [ABSTRACT FROM AUTHOR]

Abstract This paper presents a numerical evaluation of the eddy viscosity turbulence models (the zero-equation, one-equation, k - ε group and k - ω group models) in terms of CFD modelling of convection-radiation coupled heat transfer in indoor environment. The results show that all the models except the zero-equation model have acceptable accuracies to predict the bulk air temperature. However, the zero-equation and one-equation models seriously overpredict the convective heat transfer coefficient at the heater surfaces while the k - ε group models severely underpredict it, ultimately resulting in the incorrect predictions of the thermal buoyancy flows and contaminant dispersion. On the contrary, the k - ω group models perform best to calculate the convection-radiation heat split, which is critical to the successful predictions of the near-wall flow field and distribution patterns of the contaminants. This study also demonstrates the importance of simultaneously considering the convective and radiative heat transfer mechanisms when evaluating the turbulence models for indoor environment simulations. [ABSTRACT FROM AUTHOR]

Highlights • Impacts of fouling and ambient temperature on ASHP's performances were studied. • Increased fouling level and ambient air temperature led to poorer performances. • An equivalent temperature rise due to fouling was proposed and evaluated. • An improved simulated fouling approach was experimentally validated. Abstract Air source heat pumps (ASHPs) have been widely used for providing buildings with heating in winter and cooling in summer. In certain locations, with an increased level of air pollutions, fouling of the outdoor coil in a space cooling ASHP unit may appear, which affects the operating performances of the ASHP unit. Furthermore, the operating performances of an ASHP unit can also be affected by ambient air temperature (T a). In this paper, a field study on the effects of outdoor coil fouling at different T a on the operating performances of a field space cooling ASHP unit is presented. The study results demonstrated that the operating performances of the field ASHP unit were significantly affected by the changes in both T a and percentage of fouled outdoor coil surface (PFOCS). For example, at T a = 30 °C, the variation in PFOCS from 0 to 100% led to a reduction in COP for the field ASHP unit from 2.7 to 2.0. At a fixed PFOCS of 60%, the changes in T a from 26 to 33 °C resulted in a reduction in COP from 2.6 to 2.1. In order to more conveniently investigate the combined impacts of fouling on the operating performances of an ASHP unit at different T a , an equivalent ambient air temperature rise (ETR) was proposed. Based on the measured and evaluated operating parameters of the field ASHP unit at different T a and PFOCS values, ETR values at 0 - 40%, 40 - 60%, 60 - 100% and 0 - 100% PFOCS ranges were evaluated. These ETR values implied that defouling of a fouled outdoor coil may be initiated when PFOCS was at 40 - 60%. With the ETR values for the full PFOCS range of 0 - 100%, the impact of full fouling on the operating performances of an ASHP unit may be evaluated as if it was operated with a clean outdoor coil but at an equivalent ambient air temperature of T a + ETR. [ABSTRACT FROM AUTHOR]

Highlights • The Thousand Pillars Dwelling is taken as research objective to explore its climate adaptation strategies and adaptation effectiveness for the local climate in the view of passive elements and passive spaces. • The performances of climate adaptation based on the passive elements (composed of doors, windows, walls, etc.) and passive spaces (composed of patios, corridors, etc.) for the indoor comfort level in Thousand Pillars Dwelling is researched qualitatively. • The on-site measurements of air temperature, relative humidity, air velocity and illuminance in diverse parts of Thousand Pillars Dwelling were carried out to research the improvement level of indoor comfort quantitatively. • Due to the passive elements and passive spaces with remarkable elasticity effects on mitigating impacts of the outdoor climate and maintaining the indoor micro-climatic environments stable, they contribute to the extension of indoor comfort time effectively. Abstract Relying on passive climate-responsive strategies, traditional dwellings can effectively control the indoor thermo-hygrometric and daylighting conditions by taking advantage of some favorable climatic elements like wind, solar radiation, etc. Furthermore, the building's elements and spaces can be regulated to make the indoor microclimate reach the comfort limits thanks to these passive strategies. In this paper, the Thousand Pillars Dwelling (TPD) is taken as a research objective to explore its climate adaptation strategies and effectiveness for the local climate in the view of passive elements (PEs) and passive spaces (PSs). By the methodologies of literature reviews, field investigations and software simulations, the buffer effect (BE) created by PEs (composed of doors, windows, walls etc.) and PSs (composed of patios, corridors etc.) contributing to the improvement of indoor comfort level (ICL) is researched qualitatively. An additional study on in-situ measurements of air temperature, relative humidity, air velocity and illuminance in diverse parts of TPD was carried out to research their effectiveness of climate adaptation quantitatively. This study shows that BEs are effective at mitigating the impact of outdoor climate on internal spaces, which is helpful for the extension of indoor comfort time (EICT) by 3472 h per year. The research results of passive strategies are summarized from the study case of TPD and its effectiveness of climate adaptation can provide some methods and implications to create more comfortable indoor environments for rural residences. [ABSTRACT FROM AUTHOR]

Abstract: The shortcomings or limitations of the traditional approach to developing energy efficient buildings are that they can not determine: (1) the ideal thermophysical properties of building envelope material, where “ideal” means that such material can use ambient air temperature variation and/or solar radiation efficiently to keep the indoor air temperature in the thermal comfort range with no additional space heating or cooling; (2) the best natural ventilation strategy; (3) the minimal additional energy consumption for space heating in winter or air-conditioning in summer. To overcome these problems, some new concepts for developing energy efficient buildings are put forward in this paper. They are the ideal thermophysical properties of the building envelope material, the ideal natural ventilation rate, and a minimal additional space heating or cooling energy consumption. A new approach for determining these properties is also developed. In contrast to the traditional approach (the thermophysical properties of building envelope material are known and constant so that the relating equations describing the indoor air temperature tend to be linear differential equations), the new approach solves the inverse problem (thermophysical properties, etc. of a buildings are unknown), whose solution can be a function instead of a value. As a first step, the ideal specific heat of the building envelope material for internal thermal mass is analyzed for buildings located in various cities in different climatic regions of China, such as Beijing, Shanghai, Harbin, Urumchi, Lhasa, Kunming and Guangzhou. We found that the ideal specific heat is composed of a basic value and an excessive one which is of δ function for the cases studied. Some limitations that would need further study are introduced in the end of the paper. [Copyright &y& Elsevier]

Highlights • PCM was applied to disaster-relief PTHs for improving indoor thermal environment. • Two different Designs of applying PCMs to PTHs were experimentally studied. • Using PCMs can help improve the thermal environment inside PTHs. • The Design of a movable PCM energy storage system (PESS) was preferred. • Low temperature outdoor air at nighttime may be used for charging the PCMs. Abstract During disaster relief reconstructions, prefabricated temporary houses (PTHs) have been extensively used for resettling disaster victims. However, due to the nature of disaster relief, PTHs are normally light-weighted, without an electrical thermal environmental control systems installed. Hence, the thermal environments inside these PTHs can become intolerably hot in summer. Therefore, simple and low cost measures should be applied to disaster-relief PTHs for improving their indoor thermal environments. In this paper, an experimental study on applying PCMs to disaster-relief PTHs is reported. Two different designs of applying PCMs were examined. In Design 1, PCMs were fixed to the internal surfaces of a model PTH and the related experimental results demonstrated that both indoor air temperature and internal surface temperature of the model PTH can be reduced at daytime. However, in Design 2, a movable PCM based energy storage system (PESS) was used and the related experimental results suggested the use of the mobile PESS with a total charge of 148.8 kg PCM helped reduce the average indoor air temperature by 3.2–3.6 °C. The experimental results from both Designs suggested that, due to the nature of disaster relief and since outdoor air at a lower temperature may be the only cooling energy source for charging the PCM, a movable PESS system was preferred, so that it can be moved to outdoor at nighttime for being charged with more cooling energy using lower temperature outdoor air not adversely increasing the air temperature inside PTHs. [ABSTRACT FROM AUTHOR]

Over the last few years, studies have predicted an increase in the overall air temperature due to climate change. Today's society is already sensing this change, which could have a negative impact on the environment and efforts are being made to seek all possible measures to curb it. One of the consequences of this temperature rise would be its effect on indoor comfort within buildings, which may cause higher energy consumption and operational costs, while reducing the useful lifetime of air-conditioning equipment. In this paper, an existing zero energy building (ZEB) is being studied to understand the possible effects of climate change on its zero energy status. The building is also a zero carbon building because all of its generated energies come from renewable sources (biomass, geothermal and solar photovoltaic systems). The building LUCIA has the highest innovative technologies in energy systems, design and construction elements and is currently considered as one of the top three buildings with the highest LEED certification in the world. According to current European regulations, buildings will tend to become self-sufficient in terms of energy after 2020, and therefore this study will help us to understand the changes in energy consumption within a long-term timeframe, for such zero-energy buildings. With the aid of the Design Builder version 5 software and its EnergyPlus building energy engine, a building model is simulated and energy consumption is analyzed for the years 2020, 2050 and 2080 timeframe. The climatic conditions pertain to the city of Valladolid, Spain, which has a continental climate, while the expected changes in climatic conditions have been produced through the methodology developed by the University of Southampton, called CCworldweathergen. Results have shown that the cooling demand would significantly increase for the years 2050 and 2080, while space heating would drop. This will increase the overall demand for burning more biofuels to cover the added demand in absorption cooling systems. Moreover, the previously excess generated electricity of the building by photovoltaics would then be totally consumed within the building due to increased demand. This implies that the installed systems will operate for longer hours, which will increase maintenance and replacement costs. As a result of this study, it becomes possible to quantify the expected changes in energy consumption and prepare preventive actions to anticipate this change, while improving the management and control of both the energy systems and the building. [ABSTRACT FROM AUTHOR]

The aim of a personalized heating system is to provide a desirable microclimate for each individual when heating is needed. In this paper, we present a method based on machine learning algorithms for generation of predictive models for use in control of personalized heating systems. Data was collected from two individual test subjects in an experiment that consisted of 14 sessions per test subject with each session lasting 4 h. A dynamic recurrent nonlinear autoregressive neural network with exogenous inputs (NARX) was used for developing the models for the prediction of personalized heating settings. The models for subjects A and B were tested with the data that was not used in creating the neural network (unseen data) to evaluate the accuracy of the prediction. Trained NARX showed good performance when tested with the unseen data, with no sign of overfitting. For model A, the optimal network was with 12 hidden neurons with root mean square error equal to 0.043 and Pearson correlation coefficient equal to 0.994. The best result for model B was obtained with a neural network with 16 hidden neurons with root mean square error equal to 0.049 and Pearson correlation coefficient equal to 0.966. In addition to the neural network models, several other machine learning algorithms were tested. Furthermore, the models were on-line tested and the results showed that the test subjects were satisfied with the heating settings that were automatically controlled using the models. Tests with automatic control showed that both test subjects felt comfortable throughout the tests and test subjects expressed their satisfaction with the automatic control. [ABSTRACT FROM AUTHOR]

Providing the occupants with tailored feedback on their energy consumptions can be an effective method to help the users to adopt energy-efficient behaviours. However, in specific contexts such as the social housing, this may be challenging, due to the peculiarities and the economic constraints of the end-users, which make them vulnerable and needing a proper design of the information. Nevertheless, there is a lack of detailed studies in the literature analysing the effects of personalized energy feedback on the space heating consumption and the indoor air temperatures in the social housing sector. This paper aims to evaluate the effects on space heating consumption and indoor air temperature of a personalized feedback campaign delivered in three social housing buildings consisting of 27 apartments in Mediterranean climate. To this end, a personalized feedback campaign was designed and developed, providing for the use of disaggregated energy consumption indicators to show the location of excessive thermal energy consumptions. The daily thermal energy consumptions, as well as the indoor air temperatures of the single dwellings, were monitored daily for over four heating seasons and their variations were analysed before and after the implementation of the personalized feedback. A saving in normalized natural gas consumption of the buildings was found on average equal to −14,8% after the feedback campaign, with no significant variations in the indoor air temperatures. However, some critical issues have been highlighted in the response of individual end-users to the feedback provided. A greater propensity of the occupants to regulate the indoor air temperature through the thermostatic radiator valves in the unoccupied rooms of the house was also observed after the occurrence of the feedback campaign. [ABSTRACT FROM AUTHOR]

Optimizing efficiency in the operation of the HVAC system of existing buildings requires the construction of a thermal dynamic model of the building, which may be challenging because architectural metadata may be missing or obsolete. Based on a suitable set of measured data, this paper presents a novel practical methodology to create and automatically derive thermal models of existing buildings in high-fidelity simulators for energy management. To this end, the philosophy of grey-box strategies is followed to simplify the modeling and avoid the requirement of architectural metadata, facilitating and expediting the process. First, a building model with a highly reduced number of parameters is constructed by exploiting the existing similarities in the materials of the buildings and simplifying their elements to a simple one-layer parameterization. Then, the parameters of the derived model are iteratively updated while minimizing the error between the real temperature evolution and that generated by the model being identified. For this purpose, data of the room air temperature, estimated occupancy, weather conditions, and variables of the HVAC system are assumed to be available in suitable zones of the building to apply the creation and identification processes of the model, allowing that a whole digital twin of the building is constructed. The methodology is presented by its application to a real case study: the Nimbus Research Centre building at Munster Technological University, located in Cork (Ireland). The high-fidelity simulator software TRNSYS is used for the modeling task, together with the GenOpt optimization program. The results demonstrate that the proposed methodology yields a highly accurate model of the building, capable of representing reality with RMSE values consistently below 0.6 C ∘ during open-loop validation periods of up to four days. The findings suggest that this methodology may outperform other modeling techniques reported in the literature. Importantly, the proposed technique is less complex and time-consuming to implement than many of the alternatives. • Thermal modeling of existing buildings avoiding the use of architectural metadata. • Novel integration of grey-box modeling methods with high-fidelity simulators. • The proposed method copes with the drawbacks of the models found in the literature. • Methodology validated with experimental data from the Nimbus Centre (Ireland). • Results show high accuracy of greatly simplified models—RMSE<0.6 °C in 4-day horizons. [ABSTRACT FROM AUTHOR]

• The TPAM algorithm can predict the outdoor air temperature using one parameter. • The prediction accuracy is between 71.9% and 95.6%, with the average more than 80.0%. • Skipping time window can effectively keep the temperature's seasonal characteristics. Accurate prediction of outdoor air temperature is of great significance to improve the energy efficiency of HVAC system and even the whole building. The aim of this paper is to present the development and evaluation of a new algorithm based on pattern approximate matching for the prediction of outdoor air temperature using acquired historical data of five cities in China (Beijing, Harbin, Shanghai, Guangzhou and Kunming) representing different climatic regions. The optimum parameters of the algorithm for each city has been identified by its historical data. The efficiency of the prediction is validated by comparing predicted and measured outdoor air temperature. Furthermore, statistical metrics such as absolute mean error (AME), root mean square error (RMSE), and accuracy were used to evaluate the performance of the algorithm. These metrics confirm the algorithm proposed in this paper is suitable for all the five Chinese cities. All the work has been contacted using Python programming environment. [ABSTRACT FROM AUTHOR]

• The finite volume method (FVM) was examined to investigate application of electric heating cables (EHC) in the construction of floor heating panels (FHP). • The dynamic model in EnergyPlus was investigated. • The internal air temperature was monitoring. • Study was conducted to the test model chamber. Among panel heating systems (PHS), floor heating (FH) is mostly used in Serbia because it offers special benefits in terms of thermal comfort and final energy consumption. Uniform temperature distribution in the hanging room, low temperature mode, fairly simple way of installation and maintenance, long service life, simple ambient temperature control and currently low price of electricity in Serbia, is the reason for the increasing use of electric heating cables (EHC) in PHS. In addition to a number of advantages, when using floor heating panels (FHP), it must be taken into account that the maximum temperature of the available free floor surface does not exceed the recommended limits because it has a negative impact on thermal comfort in the room and negatively affects the health of users. In this paper, the subject of experimental and numerical research is a low-temperature electric floor heating panel (LTEFHP) in specific conditions. In the experimental part of the paper, a two-storey test house (TH) was used, with dimensions of one floor, ie. thermal zones 1 000 × 800 × 650 mm, within which a pre-prepared physically prepared electric heating panel (EHP) is implemented as an active heating system. In order to test the test houses and the mentioned heating system under stationary conditions, a test chamber (TC) with dimensions 1 500 × 1 500 × 1 800 mm was used, in which the following three scenarios were simulated (when the mean air temperature inside the test chamber: t TC = -5°C, t TC = 0 °C and t TC = 4.5 °C). The same experimental installation (for the same simulation scenarios) was tested numerically in the second part of the paper, first in the EnergyPlus software, and then in the Ansys Workbench software. The main goal of this paper is to use different methods and tools to show the appropriate temperature fields in the characteristic layers of the examined geometric structure. [ABSTRACT FROM AUTHOR]

This paper is dedicated to research of impinging jet (IJV) air distribution method. This system provides the desired indoor climate in office buildings. This paper describes the experimental requirements and boundary conditions for the CFD simulation and experiment in the climate chamber. The necessary modelling scenarios were developed to review the operation of the ventilation system according to different climatic conditions (winter, summer), human positions in the room and the shape of the supply duct. It is concluded that the shape of the air opening has little effect on the contaminant and heat removal effectiveness, 114%–122% and 1.12–1.16 respectively. At the same time, there is a large impact on the air exchange effectiveness (0.74–0.91). It was experimentally noted that in terms of contaminant removal and air exchange effectiveness, the circular opening provides better results. The human position depends on the supply temperature and flow velocity. By analyzing different scenarios, it was determined that the minimum acceptable distance to maintain thermal comfort within the standard requirements from the supply outlet is 1.7 m. As the distance from the air opening increases, the vertical air temperature difference at the height of 0.1–1.1 m decreases more than 2 times – from 1.9 K/m to 0.7 K/m. It is concluded that impinging jet ventilation has a great potential for use in office spaces both in winter and summer scenarios. This system significantly improves thermal comfort and indoor air quality. Applying impinging jet ventilation (IJV), limitations and peculiarities of the system such as supply air velocity, temperature and shape of the air duct must be carefully evaluated. [ABSTRACT FROM AUTHOR]

Within the European context, most of the current residential building stock does not fulfil minimum thermal requirements and needs to be refurbished urgently. Quantitative internal infrared thermography can provide valuable information about the in-situ thermal transmittance of existing buildings for their future refurbishment. This paper aims to establish how operating conditions and thermophysical properties might affect the accuracy of the measured U -value using this technique. To assess the most influential operating conditions, one experimental room with a heavy single leaf-wall was chosen to develop the research in quasi steady-state conditions, with a wide temperature difference range (3.8 < Δ T  < 21   °C). A statistical analysis demonstrated that the variance in thermal transmittance could mainly be predicted by changes in the outer air temperature. To analyze the impact of the thermophysical properties, specifically the heat capacity per unit of area, four unoccupied residential buildings with heavy multi-leaf walls were tested (6 < Δ T  < 10   °C). The results mainly showed that the quantitative internal infrared thermography method is more accurate in heavy multi-leaf walls with high kappa values, reaching maximum deviations of 0.20%. [ABSTRACT FROM AUTHOR]

Outdoor thermal comfort in urban spaces is gaining increasing research attention because it is associated with the quality of life in cities. This paper presents an ordered probability model for predicting the probability distribution of thermal sensation votes (TSVs) based on 1549 observations obtained from a large-scale field survey conducted at a park in Tianjin, China. With a given set of inputs, the developed model can predict the probability that people will feel cold, cool, slightly cool, neutral, slightly warm, warm, or hot. The predictive capability of the ordered probability model was systematically assessed by comparing it with the survey data and a traditional multivariate linear model. Both models had a similar accuracy in predicting single-value TSVs. However, the ordered probability model performed much better than the multivariate linear model in predicting the probability distribution of TSVs. A sensitivity analysis of the ordered probability model revealed that outdoor air temperature was the most important influencing factor. The impacts of global radiation, relative humidity, and activity level on predicted thermal sensation depended on the outdoor air temperature. The developed ordered probability model was used to predict suitable time periods for holding outdoor activities in Tianjin across a whole year. This new model is a more informative tool for predicting outdoor thermal comfort. [ABSTRACT FROM AUTHOR]

This paper investigates the efficiency of a naturally ventilated double-skin façade (DSF) built in a test cell focusing on the airflow and heat convection of the cavity formed by DSF. The study covers measurements of the test cell and their numerical simulation. DSFs have been widely researched worldwide, since they contribute to the thermal performance of the internal environment and to energy savings by eliminating mechanical conditioning systems. For data acquisition, type K surface thermocouples are installed on the wall faces of the test cell and the additional façade, that is, on the inner and outer face of the wall of the test cell and the inner face of the external one. Furthermore, hot wire anemometers are positioned so as to obtain the air velocity in the lower and upper openings of the cavity, which has an air layer thickness of 0.1 m. The results show that the DSF presence contributes to a decrease of the temperature inside the environment because it inhibits the direct solar radiation. Measurement of the faces shows that at 4:00 p.m. the temperature reaches their maximum values. These values are equal to 25.6   °C on the inner face of the façade and 23.6   °C on the inner face of the test cell, while the outdoor temperature presents values equal to 23.1   °C at this time. [ABSTRACT FROM AUTHOR]

Heat transfer through external walls plays a significant role in building energy saving. This paper tries to investigate the thermal and energy performance of a novel lightweight steel-bamboo wall structure. A testing residential building was constructed using the prefabricated steel-bamboo composite wall and field measurement was carried out to determine the heat transfer coefficient, time lag and decrement factor of the steel-bamboo wall. Numerical simulation was conducted in order to further evaluate its performance improvement compared to two commonly used wall structures in this climate region. The results show that the steel-bamboo wall has a high thermal performance with an improvement of U value by up to 26.1%–48.4%, indicating a lower heating demand compared to common wall structures in winter. Meanwhile, it has a high resistance to outdoor air temperature fluctuation with a low decrement factor of 0.022. The relatively low time lag (2 h) contributes to a lower indoor temperature during summer nighttime and thus reduces cooling energy demand. The improvement of total energy performance reaches 27.1%–40.9%, indicating a great potential of applications of this steel-bamboo wall in residential buildings in hot summer and cold winter zone. However, the main drawback of the steel-bamboo structure is that its indoor thermal performance during the hottest hours in summer is poorer than conventional walls. [ABSTRACT FROM AUTHOR]

Heat output and uniformity of surface temperature distribution are primarily concerned by designers and users of radiant floor heating. The testing approach, testing conditions and calculation of the heat output at each stage of program are different among the test standards. In this paper, a mathematical model to calculate surface temperature and heat output of radiant floor heating system was proposed. Measured data from experiments was used to validate the proposed model. Based on this simulation model, four current test standards in China, Europe, America and Japan were simulated. The simulation results show that the heat output of the same sample is different under the four test standards. Meanwhile, simulations were carried out at various non-heating surface temperatures. The results indicate that the non-heating surface temperature has a significant impact on the heat output of the radiant floor. The differences in the simulations of heating capacity vary from 2% to 7%. Hence, a parameter, the temperature difference between average water temperature of test sample and area weighted average temperature of non-heating surfaces, is introduced to revise the heat output characteristic equation based on the Chinese test standard. [ABSTRACT FROM AUTHOR]

In the case of highly efficient buildings the solar and internal gains have a higher impact on the energy balance than on classical constructions, with lower insulation. In this context, a model was developed which considers the three dimensional heat transfers through the walls. It simulates the transient behavior of rooms with the use of a refined spatial and temporal discretization and considers the projection of solar radiation through a window onto interior walls, referred to as sun patch. Validation of the model was carried out using experimental data from a low energy cell operating in a natural climate. Shorter sampling steps seem necessary to consider accurately the fluctuations of the weather data and the short dynamics of the systems such as the regulated heaters. In this paper, simulations with weather data at different time steps (1 min, 10 min and 1 h) are going to be analyzed. The impact of the contribution regarding the adaptive and variable time step of the differential equation solver will also be shown. Finally, the impact of the different time steps on the accuracy of the low energy cell’s temperatures and heating loads will be discussed. [ABSTRACT FROM AUTHOR]

This study is focused on the evaluation of the effectiveness of vacuum insulation panel (VIP) for typical Mediterranean climate. The interest for this material is due to indisputable advantages in term of insulation performance both for new and refurbished buildings; mainly in retrofit design, adoption of lower thickness assure same results with less invasive interventions. The problem is the behavior during the summer period, not investigated in the available scientific literature. Numerical and experimental approaches are used in this paper to compare the performance of several wall packages integrating VIP with constructive technologies that result in different stationary and dynamic parameters. More in detail the results of a yearly measurement campaign in three real building of south Italy are presented; recorded data of the surface and the mean air temperatures as well as of the heat flux are commented. Data for one typical week of each season are evaluated to compare the wall made of concrete block and vacuum insulation material with a massive structure and also with a concrete wall with expanded polystyrene as insulation material. Furthermore, simulation results (by means of EnergyPlus) are presented to study, mainly during the summer, the effect of integration of vacuum insulation panel in multi-layered wall made of concrete blocks with different values of density and thermal conductivity; moreover these configurations are compared with a wall made of innovative insulated interlocking brick and with the wall types considered in the experimental phase. Using a typical office building as case study, energy consumptions and environmental and economic indexes are valuated. Experimental and numerical results show the effectiveness of solution with VIPs also for Mediterranean climate. [ABSTRACT FROM AUTHOR]

Heat-related mortality is of growing concern for cities faced with the combined effects of increasing heat-wave frequency and intensity and stronger urban heat islands (UHI). In cities around the world, high air temperatures have been found to have strong repercussions in terms of heat-related mortality for populations aged 65 years and older, especially nighttime temperatures. In response, many measures have been proposed to counteract the effects of UHI such as cool roofs and materials or urban greening. While these approaches are promising and are rightfully explored, behavioral adaptation measures have not received as much attention. Given the importance of nighttime temperatures on heat-wave mortality and the importance of sleep quality for individuals to recover from intense daytime heat exposure, adapting sleeping habits to reduce sleep time exposure to intense heat may help reduce the health impacts of heat-waves. In this paper, outdoor and indoor temperature measurements conducted over the summer of 2015 in the bedrooms of two apartments in Paris, France are analyzed. The potential for this kind of behavioral adaptation to reduce occupant exposure to high sleep time temperatures is quantified and discussed. The policy implications of our findings and their practicality are also mentioned. [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]

This paper focuses on the assessment of a microclimate in a city canyon in Vienna, accurately the Vienna Karlsplatz. In this canyon, there are several environments. The goal of this study was to inquire weather it makes an identifiable difference if an urban place is planted or not. This study was a comprehensive in situ investigation. The air temperature and relative humidity were tested in two places, with the first one being surrounded by greenery, and the other one by “asphalt/concrete”. The thermal behavior was recorded and analyzed over various heat waves. After analyzing the complete period, two extreme heat waves of three days were singled out and analyzed in detail. Finally, this investigation is completed by an analysis of the environmental impact of a greenery in the middle of a city at summertime. It shows that the effect of temperature reduction can have a positive impact on the buildings surrounding. It is mainly the night cooling that shows the most temperature differences. Therefore, greenery in the city has a powerful impact on the role of passive cooling of a building surrounding and consequently of buildings cooling if the building ventilation behavior is correctly followed. [ABSTRACT FROM AUTHOR]

This paper focuses on influences of a “green-buffer-space” (GB) on the photovoltaic-module (PV) temperatures. The described results correspond to the first year of research. They are part of an ongoing project-development: “Multifunctional System: Building Greening and Photovoltaic” (MFS). The MFS combines two well-known systems: photovoltaics and green façades. The aim is to evaluate the synergies and benefits of the system on its components − the PV, buffer space (BS) and green facade (GF) − on the building façade (BF). The presented outcome shows the effects of the GB layer on the PV layer. The analysis focusses on two PV systems of the same technology and power output, but with different buffer spaces: one with a GF and the other one without a GF. The first two assumptions were confirmed: the plants can growth behind PV mounted on a façade, and the GB acts as a temperature regulation tool. The GB reduces the PV operating temperatures in increasing ranges, about 1 °C up to 4 °C. Temperature differences increase by outdoor temperatures above 20 °C, i.e. the GB benefits are higher under higher outdoor temperatures. The third one, GB benefits on the PV performance were positive for specific time intervals: when the PV module was operating under extreme conditions, what requires further research. [ABSTRACT FROM AUTHOR]

This paper shows the investigation of a living wall system inside a classroom. Humidity, temperature and the CO 2 -concentration were measured in two classrooms with the same volume. One of the classrooms is equipped with a living wall system. Air temperature and relative air humidity were investigated for 10 months including summer and winter months. In winter the increased relative air humidity of the greened classroom improved the comfort level. In summer mould spores were also investigated in the classrooms and outdoor. Spores from Cladosporium , Penicillium , Aspergillus versicolor , Alternaria and other were found, but the concentration of the mould spores in the greened classroom was below the mould spores concentration in the not greened classroom or outside. The volume of the mass of the plants is about 1 % of the classrooḿs volume. But still a small CO 2 -reduction because of the plants was measured. [ABSTRACT FROM AUTHOR]

The main objective of the paper is to assess the impact of different factors which include building and human comfort parameters on indoor temperature conditions and energy need for heating for complex system “heat source – human comfort – building envelope”. The proposed method of mean radiant temperature calculation for human comfort models, which takes into account incoming solar radiation, will increase the accuracy of calculations by 1.3% – 4.7%. Regression models for comfort room air temperature determination, developed on the basis of energy and exergy human comfort approaches, significantly simplify further calculations and can be incorporated in complex system. As comfort temperature, determined in accordance with exergy approach is lower than based on energy one, the exergy concept use for providing comfort conditions accounts for less energy need for heating. Modelling results of various factors impact on energy need for heating are obtained based on energy and exergy approach to human comfort. [ABSTRACT FROM AUTHOR]

This paper aims to compare thermal comfort responses from office workers in both fully air-conditioned and mixed-mode buildings against both the analytical and adaptive models of thermal comfort of ASHRAE 55-2013. Occupants were asked to record their thermal perception in questionnaires delivered online while instantaneous instrumental measurements were taken in situ (air temperature, radiant temperature, air velocity and humidity). Three buildings were investigated in a temperate and humid climate, i.e., in Florianópolis, southern Brazil. Two buildings have mixed-mode operation and one building has central air-conditioning. Almost two thousand six hundred questionnaires were collected during field studies. Actual thermal sensation and acceptability votes were compared against two predictive models of thermal comfort: the analytical model and the adaptive model. The 80% and 90% acceptability limits of indoor operative temperature used in the adaptive model were calculated using the prevailing mean outdoor air temperature. The analytical model overestimated the cold sensation of users, mainly for natural ventilation mode, and did not properly predict the percentage of thermal dissatisfaction of users. The analytical model could be used only when air-conditioning is operating; and a wider range of indoor thermal conditions than recommended by ASHRAE 55-2013 is recommended to be adopted during air-conditioning operation. The application of the adaptive model seems to be inappropriate for fully air-conditioned buildings. This work was not conclusive about the use of the adaptive model when the air-conditioning is on in mixed-mode buildings due to few data collected in this mode of operation. Under natural ventilation operation in mixed-mode buildings, occupants adapted to temperature fluctuations as predicted by the adaptive model, however, occupants appear to be more tolerant to cool conditions. The adaptive model may be used in mixed-mode buildings, when the air-conditioning is not on. [ABSTRACT FROM AUTHOR]

The use of indirect evaporative cooling technologies is an effective way to reach high energy efficiency systems and to reduce primary energy consumption. At present, interest in such systems is strongly increasing, with particular attention to data centers facilities. In fact, in these applications the indoor air temperature can be higher than the one of residential and commercial buildings, leading to a greater number of yearly operating hours of the system. In this paper an indirect evaporative cooler, based on a cross flow heat exchanger, has been tested and modelled. Many experiments have been carried out in typical data centers operating conditions, varying both water flow rate and inlet air conditions. A phenomenological model of the indirect evaporative cooler has been developed: the model takes into account the effects of the adiabatic cooling of the secondary air stream in the inlet plenum and the actual wettability of the heat exchanger surface. The model has been extensively validated and it is shown that simulation results are in very good agreement with experimental data. Therefore, it can be a suitable tool to design and to predict performance of indirect evaporative cooling systems. [ABSTRACT FROM AUTHOR]

Air temperature and speed play a critical role in the thermal sensation of comfort felt by occupants, especially in the tropics. It is of great practical interest to coordinate air conditioning and mechanical ventilation (ACMV) system and personal fans so as to enhance building demand response (DR) capability while minimizing energy cost in response to a specific electricity price signal and maintaining a thermal comfort level. In this paper, an optimization problem of coordinating ACMV and personal fans is addressed, which captures the coupling between ACMV and fans. A Lagrangian relaxation-based algorithm is developed to solve the problem by individually solving the subproblems of ACMV and personal fans with Lagrangian multipliers as the coordinated signals. This algorithm can separate the calculation of the cooling effect from the optimization procedure, so we do not have to solve the problem using a non-analytical model for evaluating the cooling effect provided by the fans. The performance of the proposed method is evaluated and validated using experimental and simulation results. Both the results show that coordinating ACMV and fans can substantially enhance building DR capability, save energy cost, and also improve customized thermal comfort microenvironment. [ABSTRACT FROM AUTHOR]

Natural ventilation represents one of the challenges in green buildings design since the most important parameter that reflects the quality of building design is the thermal comfort within the indoor environment. This paper introduces experimental and numerical investigations for evaluating the impacts of natural ventilation on the thermal comfort inside residential buildings. Computational fluid dynamics (CFD) simulations were carried out to assess the wind environment within the study domain. Then, the solved flow field was used to calculate the temperature field. Validation of the simulation results was performed using experimental measurements. The parameters considered in the study were the air velocity, relative humidity, and the dry bulb air temperature. The study results show that there are significant thermal discomfort conditions inside the study domain, due to the lack of air circulation within the domain as a result of the building geometry. Accordingly, the obtained results reflect the need for design modifications in window parameters (window size, window placement, and shades) to improve the thermal comfort within the domain. Applying the design modifications led to a decrease in the air temperature by 2.5% and an increase in the air velocity within the study domain by six times. [ABSTRACT FROM AUTHOR]

Scale experiments that use water of different salinities to represent air at different temperatures are a common tool used to investigate room air ventilation. However, it has been shown that these experiments cannot replicate the effects of radiation heat transfer in a room. This paper illustrates the importance of accounting for radiative effects when modeling airflow, especially regarding the air temperature profile. Computational fluid dynamics simulations were performed of flow in heated rooms with and without radiation. It was found that when radiation was ignored the temperature of the air surrounding the occupants was significantly lower, by 2–4 °C, than when including its effects. In addition, the surface temperature of the heat sources was consistently higher (up to 17 °C) when ignoring radiation. Finally, air velocity in the space was higher in simulations that included radiation. These differences have an important impact on the predicted thermal comfort of the occupants, since neglecting radiative heat transfer would result in an inaccurate estimation of operative temperature. We conclude that water scale models do not provide an accurate description of flow behavior in a space, so desired thermal and flow conditions might not be achieved in buildings designed or assessed using water scale models. For these reasons, theoretical models or computer simulations that omit radiation will also give misleading predictions of room temperature distribution. [ABSTRACT FROM AUTHOR]

• Selected the outdoor design conditions based on simultaneous occurrence probability. • Analyzed the dependence relation between three weather elements using vine copula. • Modeled the multivariate joint distributions of three weather elements. • The indoor thermal risk levels of outdoor design conditions were evaluated. In building design, the commonly used outdoor weather conditions recommended by ASHRAE are generated by the annual cumulative frequency of occurrence method. This may result in air-conditioning equipment capacity being overestimated. This is because the air temperature, humidity and solar radiation that have the greatest impact on indoor peak cooling loads are selected independently. It means that the probability of these three weather parameters occurring at the same time is extremely small. This paper proposes an approach for selecting the design weather data on the basis of the exact joint distribution with specific simultaneous occurrence probabilities of these three weather parameters. For this purpose, a novel statistical method vine copula is applied to construct the theoretical multivariate joint distributions of these three weather parameters for 24-hour data and combined the design parameters of each hour with a specific simultaneous occurrence probability into a design day. The hourly meteorological records over 10 years in Tokyo are used to generate the outdoor design conditions. The results indicate that the vine copula method can create an effective theoretical model and all the design parameters selected by the simultaneous occurrence probability are significantly below that of the same conventional exceeding probability. For simultaneous occurrence probabilities of 0.4 %, 1 % and 2 %, the corresponding indoor thermal risk levels are 0.46 %, 0.52 % and 0.84 %, respectively. Therefore, the proposed method can be used as a reference for designers to determine a more reasonable capacity of air-conditioning systems. [ABSTRACT FROM AUTHOR]

• A framework is developed to assess overheating in existing building in whole summer. • Calibration simulation model is used using field measurements of indoor temperature. • Overheating risk in existing school building is assessed. • Climate change effect is studied using current and future extreme RSWY years. • Effective passive mitigation measures are provided for future extreme climates. Canadian buildings have been primarily designed to withstand cold and long winters, not hot summers. With climate change and the increase in the intensity and severity of heatwaves, it has become important to investigate overheating in buildings. However, there are limited studies on assessing and mitigating the overheating risk in existing buildings that house vulnerable populations in cold climates, especially in Canada. This paper provides a framework for the systematic assessment of overheating risks and the development of passive mitigation strategies to reduce the overheating risks without increasing cooling energy consumption under current and future climates with simulation models that are calibrated based on measured indoor air temperatures and outdoor weather conditions. The framework is applied to a school building built in 1958. The calibrated building model achieved an RMSE of less than 0.6 °C compared with measurements, a Maximum-Absolute-Difference of less than 1.9 °C, and a 1 °C Percentage-Error of less than 10 %. The simulation results from the calibrated model predicted 110 overheating hours during the year 2020. The use of exterior blind roll or a combination of night cooling and other mitigation measures that reduce solar heat gain can achieve acceptable thermal conditions. In 2044 (the future extreme midterm year), night cooling with the exterior blind roll shading would be required during extreme heat events. Whereas during 2090 (the future long-term extreme year), additional mitigation measures such as a cool roof may be required to achieve an acceptable level of thermal conditions in the school. [ABSTRACT FROM AUTHOR]