bluuebunny/crossref_metadata_2025 huggingface dataset:
Experimental evaluation of phase change material in radiant cooling panels integrated with thermoelectric modules
Authors: Kang Yong-Kwon , Kim Beom-Jun , Yoon Soo-Yeol , Jeong Jae-Weon
Published: August 2019

This study proposes a phase change material for use in radiant cooling panels integrated with thermoelectric modules (PCM–TERCP) and evaluates its performance characteristics during the solidification and melting process of phase change materials in design conditions. The PCM–TERCP consists of phase change materials (PCMs), thermoelectric modules (TEMs), and aluminumpanels. TEMs operate to freeze the PCM, and PCM stores the cooling thermal energy to maintain the constant surface temperature of the panel for radiant cooling. The main purpose of thermal energy storage systems is the shift of the electricity consumption from day-time to night-time during the summer season. Therefore, PCM–TERCP can implement off-peak operation according to which energy is expected to be saved. The melting temperature of PCM and the target surface temperatures of the bottom panels of PCM–TERCP were designed to be 16°C. Additionally, the room temperature and mean radiant temperature (MRT) was set to 24°C, while the thickness of the PCM pouch was 10 mm. As a result, the solidification process required 4 h and the total input power was 0.528 kWh. Correspondingly, the melting process can operate passively over a period of 4 h. In most cases, the operating temperature was lower than 19°C, which validates the temperature response of PCM–TERCP.
Experimental investigation of different nozzle designs inside active chilled beams
Authors: Rohn Max , Mathis Paul , Müller Dirk
Published: August 2019

The aim of this study is to improve the performance of active chilled beams (ACB) by varying the nozzles cross section geometry. Most of the common ACB today have circular nozzles for the primary air plenum, as they are easy to produce and ensure a good performance. The amount of induced secondary air and thereby the performance of the system can be increased by improving the properties of the primary air jet. In other research fields like engine jets or air diffusers, different nozzle designs have been developed to enhance the jets mixing. In this study, a generic test bench is built to investigate different nozzle designs for ACB. The flow field is investigated with particle image velocimetry (PIV) which gives detailed information about the jet’s shape. The designed test bench ensures optical access to the flow field while the induced room air is measured via differential pressure methods. The cross-shaped nozzle achieved the best results among the investigated ones and could significantly increase the induced air amount. An elliptic opening also shows promising results but cannot reach the performance of the circular nozzle in this study. A rectangular nozzle opening turns out to be unsuitable in ACB.
Numerical Analysis of Air Flow in a Modular Fan Unit Using CFD Simulation
Authors: Zelenský Petr , Barták Martin , Zavøel Vojtìch , Zmrhal Vladimír , Krupa Radislav
Published: August 2019

The current regulation of European Commission No. 1253/2014 regarding Ecodesing requirements for ventilation units, which classified them based on the Specific Fan Power (SFP), has been driving the innovation in the sector of air-handling systems. The required energy saving can be met by applying modern and energy efficient Electronically Commutated (EC) motor which, at the same time, significantly change the internal geometry of the fan unit. The paper deals with design of a new type of modular fan unit ALTEKO Alton with EC motor and unhoused backward curved impeller. The design development and optimization of the fan unit leading to the reduction of generated aerodynamic noise, lower pressure loss and better outflow characteristics is supported by the Computational Fluid Dynamic (CFD) simulations, which enables visualization of air streamlines, velocities and pressure contours within the unit. Such a design is an iterative process between CFD specialist and construction team, where, based on the simulated results, the critical spots are identified, the geometry is improved and again verified throughout the CFD simulation. The paper describes in detail the individual steps of the optimization study, starting with the import of the detailed geometry from the design CAD software and its necessary simplification for the use in the CFD study, meshing of the model and consequent simulation. The methods of the fan rotation approximation are discussed as well. Additionally, the optimum position of heat exchanger in front of the fan unit is addressed. The presented work is a part of a project supported by the EU under the Operational Program Enterprise and Innovation for Competitiveness.
Airflow characteristics under planar opposed ventilation jets in a controlled indoor environment
Authors: Lestinen Sami , Wesseling Mark , Kosonen Risto , Koskela Hannu , Müller Dirk
Published: August 2019

Healthy, comfortable and intelligent indoor environment is a key objective in comprehensive well-being. This is also a main target of advanced HVAC-technology. In indoor environments, air distribution plays a major role while providing clean air to occupants. Therefore, investigating ventilation jets is an essential matter. In this study, the main objective was to improve knowledge on numerical modeling and airflow characteristics. In addition, the reliability of modeling methods were investigated. The experiments were carried out in a test room by using omnidirectional anemometers. The planar air jets were supplied below the ceiling from the opposite long-side walls. The exhaust openings were correspondingly near the floor. Isothermal and incompressible viscous airflow was simulated by using RANS, URANS, DES (SST-k-ω - LES) and SBES (SST-k-ω - LES) methods. The results show that modeling method has considerable effects on the predicted airflow field. However, the study indicates that correctly implemented numerical modeling may predict well the averaged airflow characteristics. Furthermore, the unsteady simulation allows airflows to fluctuate reasonably. In addition, SBES and DES methods were more sensitive in generating the airflow fluctuations than URANS. A recommendation is to carefully test and choose a modeling method for indoor airflows.
Effect of Air Exchange Rate on Particle Decay in a Cleanroom: A Numerical Study
Authors: Cetin Yunus Emre , Avci Mete , Aydin Orhan
Published: August 2019

In this study, particle decay in a cleanroom is investigated numerically. A commercial CFD package, FLUENT, is used in the analysis. The governing equations are solved by using the k-å turbulence model. For particle dispersion, the discrete phase model (DPM) is applied. Four different air change rates (3-10-25-43 ACH) with three particle diameters (0,5-5-10 ìm) are considered. It is shown that 10 ACH satisfies the needs in terms of recovery time.
Ventilation and environmental control of underground spaces: a short review
Authors: Li Angui , Kosonen Risto , Melikov Arsen , Yang Bin , Olofsson Thomas , Sørensen Bjørn , Zhang Linhua , Cui Ping , Han Ou
Published: August 2019

More and more underground spaces were used in 21st century because of rapid urbanization, traffic problems, etc. Underground city, metro, tunnel, mine, industrial and agriculture engineering, civil air defence engineering need large underground spaces. Underground spaces with different thermal, ventilation and lighting environments may cause comfort, health and safety problems. Concrete problems include excessive humidity, heat transfer specialty, excessive CO caused by blockage in long distance traffic tunnels, difficulty in smoke exhaust and evacuation during fire, harmful microorganism, radioactivity pollutants, psychological problems, and so forth. Air quality control technologies for underground spaces, including ventilation technology, dehumidification technology, natural energy utilization technology, smoke extraction technology and ventilation resistance reduction technology, will be reviewed. Ventilation for smoke-proof/evacuation and ventilation will also be reviewed.
Experimental study of thermal comfort in a vehicle cabin during the summer season
Authors: Danca Paul , Bode Florin , Dogeanu Angel , Croitoru Cristiana , Sandu Mihnea , Meslem Amina , Nastase Ilinca
Published: August 2019

Thermal comfort evaluation for vehicle occupants is very complicated due to the transient nature and non-uniformity of the vehicle interior. The thermal sensation of an automotive occupant is affected by the surrounding environment. More than this, the actual standard is proposing three evaluation indexes and was developed for steady state and controlled conditions and some of the indexes are not adapted for this complex environment. In this article the three standardized indexes values are compared in term of thermal comfort, in a vehicle passenger in summer season. The results are showing that the mean values of PMV/PPD model calculated in a single point with Comfort Sense equipment are far from the TSV mean values which was collected in questionnaires, while the teq index which was calculated with an advanced thermal manikin are closer to the TSV comfort votes. This may be explained by the fact that the TSV and teq consider the sensation for each body part at the local level. For a correct evaluation of the thermal comfort in non-uniform and transient environments like in the vehicles, is not enough to measure in a single point and the results to be considered in all the ambiance. The main conclusion is that the PMV/PPD indexes are not very well adapted to the vehicle environment.
A Preliminary Analysis on the Night Cooling Potential of Photovoltaic/thermal (PV/T) Panels for European Cities
Authors: Bogatu Dragos-Ioan , Kazanci Ongun Berk , Olesen Bjarne W.
Published: August 2019

A model of three PV/T collectors of 3.9 m2 area was developed in TRNSYS for analysing its cooling potential in Athens, Greece; Madrid, Spain; Milan, Italy; Bucharest, Romania; Frankfurt, Germany; Copenhagen, Denmark and Oslo, Norway between 1st of May and 30th of September. An in-depth analysis over the model was conducted for Copenhagen, Denmark where supply temperature, collector slope, and flow rate were varied. For the other six European cities subject to different climates, the only parameter varied was the supply temperature while the optimum slope for electricity production was selected for the PV/Ts. A coverage ratio was determined, representing the amount of cooling demand of an office room covered by the cooling energy produced by the PV/Ts. With respect to Europe, a higher cooling potential was found for northern climates. For a representative supply temperature of 21oC, a specific cooling power ranging from 35 to 70 W/m2 was determined. Finally, the same trend was visible for the coverage ratio, ranging from 55% to 120%. The results show that this cooling technology has a potential to be further used, when coupled to appropriate room cooling systems, such as water-based high temperature cooling systems.
Optimal PI control parameters for accurate underfloor heating temperature control
Authors: Kull Tuule Mall , Thalfeldt Martin , Kurnitski Jarek
Published: August 2019

In low energy buildings, the effect of internal and solar gains on heat balance of rooms is large. As a result, the heating systems, designed assuming steady-state conditions with no heat gains, are over-dimensioned for most of the heating period. This poses a challenge for room-based control systems, especially for thermostatic valves, but also for PI controllers. Using over-dimensioned room units might result in room temperature fluctuations. For finding solutions to this problem by using simulations, correct modelling of the control system together with the room is crucial. Therefore, the aim of this research was to determine the challenges that occur while matching measured and simulated temperature profiles and test the effect of PI control parameters on the calibrated model control accuracy. The experiments were carried out for the underfloor heating system of a test building. The building was simulated in IDA-ICE software and calibration via minimising root mean square error of energy consumption in GenOpt was carried out. The PI parameters were fit by optimisation with objective to simulate the measured temperatures accurately. The effect of the optimized PI parameters was determined by comparison to IDA-ICE default parameters and parameters from Cohen-Coon method.
Airborne transmission during short-term events under stratum ventilation
Authors: Hashimoto Kaho , Ai Zhengtao , Melikov Arsen
Published: August 2019

Past studies on airborne spread of expiratory droplet nuclei between occupants were focused on long-term exposure under steady-state conditions. However, exposure during short-term events can be widely found in practice, e.g. medical examination or short meeting. Airborne transmission during short-term events under stratum ventilation was examined experimentally in this study. Two breathing thermal manikins were employed to simulate a standing infected person and a standing exposed person. The manikins were placed face-to-face and face-to-back to reproduce the exposure conditions with the highest and the lowest risk, respectively. Tracer gas was dosed into the air exhaled by the “infected” manikin to simulate the droplet nuclei. A newly developed average exposure index was used to evaluate the exposure risk. The time-averaged exposure index increases over time, but the increasing rate depends strongly on the duration of exposure time, e.g., the exposure index increases much faster during the first 5 minutes than during the period after 5 minutes. The exposure index during short-term events does not always decrease with the increase of separation distance. These findings imply that the control measures formulated based on steady-state conditions are not necessarily effective to short-term events.
Air Quality in Sport Facilities
Authors: Grande M.S. , Cao G.
Published: August 2019

In new buildings, there are increasingly stringent requirements for ventilation, both in terms of energy consumption and air quality. Major sports facilities such as football halls, multifunctional halls and ice halls have fallen under the radar with lack of requirements concerning air quality, although materials and processes often emit more than in normal commercial buildings and houses. The aim of this project was to characterize the air quality in sport facilities. To identify the challenges concerning sport facilities, it was decided to look at ice halls. Ice halls have special demands concerning heating and cooling and therefore, dimensioning of such ventilation systems can be challenging in terms of moisture and temperature requirements. Firstly, a literature study was conducted on relevant literature concerning air quality in ice halls. The majority of previous research on indoor air quality contained research about poor air quality in ice halls because of the combustion engine in the resurfacers. The work by several previous researches confirmed that many ice halls do not have enough fresh air supply. Also, a literature study was conducted concerning bad air quality affections on productivity, health and cognitive functions. In addition to the literature study, field measurements were conducted at Dalgård ice hall to study the air quality in practice. Dalgård ice hall has no active fresh air supply or ventilation system for the ice rink. The air quality on the ice rink was measured to characterize the air quality in the breathing zone of the players. Typical air quality parameters such as particulate matter, temperature, relative humidity and CO2 concentration were measured. The PM10 values were by the ice rink stable at 80 μg/m3, and the CO2 concentration increased from 870ppm to almost 1400ppm in just under three hours with stabile high activity. Both values were above the recommended values from The World Health Organization (WHO) and Norwegian Institute of Public Health, on 50 μg/m3 and 1000ppm respectively. The conclusion was that there could be more stringent air quality requirements in such sport facilities. Young people spend a lot of time in these halls with a high pulmonary ventilation. For workers and visitors exposed to the air in the ice rink on a regular basis it is important to ensure proper air quality.
Prediction of local particle pollution level based on artificial neural network
Authors: Xiong Jie , Yao Runming , Li Baizhan
Published: August 2019

Citizens eager to know the local pollution level to prevent from air pollution. The real-time measurement for everywhere is a very expensive way, a statistical model based on artificial neural network is applied in this research. This model can estimate particle pollution level with some influencing factors, including background pollution level, weather conditions, urban morphology and local pollution sources. The monitoring from regulatory monitoring sites is considered as the background level. The field measurements of 20 locations are conducted to feed the output layer of ANN model. The average relative error of prediction compared with measurement is 9.24% for PM10 and 18.90% for PM2.5.
Indoor environmental quality evaluation in NZEB
Authors: Sánka Imrich , Schoberer Thomas , Stutterecker Werner , Petráš Dušan
Published: August 2019

The European Commission in 2010 accepted Energy Performance of Buildings Directive (EPBD) and the 2012 Energy Efficiency Directive (EED) are the main energy conservation legislative instruments for to reduce the energy consumption of new built and renovated buildings in Europe. The national regulation based on EPBD states that after the year 2016 only so called ultra-low energy buildings can be built. The next tightening in energy saving will come after 2021 (for commercial buildings after 2019), when only nearly zero energy buildings (NZEB) would be allowed to build. It means that these buildings must fulfil A0 category requirements by energy labelling.

But what about the indoor environmental quality in objects like this? This article shows results of indoor environmental quality measurement in NZEB building. Indoor air temperature, relative humidity, carbon dioxide concentration and air exchange rate had been measured. Except these parameters energy consumption from the grid and from the photovoltaic panel had been evaluated.
Investigations on noise sources on a contra-rotating axial fan with different modifications
Authors: Krause Ralph , Friebe Christian , Kerscher Michael , Puhle Christof
Published: August 2019

An Acoustic Camera was applied to examine modifications of fan blade designs regarding their noise emissions. A so-called rotational beamforming algorithm allows for the detection of sound sources on the rotating blades by using a virtual rotation of the microphones. Depending upon the frequency different sources could be localized. Both the leading and the trailing edge were modified. This paper shows the performed modifications and tests with the Acoustic Camera. It also presents first results and gives an outlook on future work.
Comparison of the thermal performance between conventional and cob building
Authors: Zeghari Kaoutar , Louahlia Hasna , Leguern Malo , Boutouil Mohamed , Gualous Hamid , Marion Michael , Schaetzel Pierre , Goodhew Steeve , Streif François
Published: August 2019

The appliance of sustainable development approach in building has urged construction industry to adopt proper measurements to protect environment and reduce residential building energy consumption and CO2 emissions. Thus, an increasing interest in alternative building materials has developed including the use of bio-based materials such as cob which is studied in this paper. In the previous work, many experimental and numerical studies have been carried out to characterize thermal behaviour of earth buildings, reduce its thermal conductivity and water content. In this paper, an experimental study is carried out to determine the thermal properties and energy performance of cob building. Cob samples within different soil and fiber contents are studied using an experimental set up instrumented with flux meters and micro-thermocouples in order to evaluate the local heat flux and thermal conductivity during stationary regime. The results are analysed and compared to deduce the performant mixes in terms of thermal behaviour while respecting the French thermal regulation. A static thermal simulation based on RT 2012 calculation method (the official French calculation method for the energy performance of new residential and commercial buildings according to France thermal regulation) is used to compare energy performance between conventional and cob building using the French climate data base .
Energy and economical evaluation of residential buildings in Slovakia
Authors: Bartošová Kmeťková Jana , Petráš Dušan
Published: August 2019

The main objective of the research is to make evaluation of energy and economic by the retrofitting of the residential buildings. If this methodology can be an appropriate tool to guide decisions related with the building energy performances and to identify the most cost-effective variants of the renovation, that could be applied to the building stock in Slovakia by the analysis of the life-cycle costs of the representative apartment buildings.

The specific objectives of this study were the following:

• Theoretical analysis of the residential buildings stock in Slovakia

• Analysis of the studied residential buildings and their energy parameters before and after renovation

• Simulation of the energy performance of the apartment buildings

• Mathematical modeling of the technical and economic parameters
Facade Refurbishment For Energy Saving In Tube Houses A case study in Hanoi, Vietnam
Authors: Nguyen Phan Anh , Bokel Regina , van den Dobbelsteen Andy
Published: August 2019

This paper investigated the energy upgrade potentials of different facade refurbishment options in tube houses of Vietnam. A calibrated Design Builder model was created to simulate energy performance of different cases. Vietnamese technical regulation of energy efficiency building and Dutch standards were the two main guidelines for selection of refurbishing measures. The simulation results showed that applying Vietnamese technical regulation can save up to 9% of energy for heating and cooling. More interestingly, highly insulated facade that followed Dutch standards led to much more favourable results of 21% reduction in air conditioner consumption. It is worth to note that such improvement was by far only achieved with a night-time operation of air-conditioner, as how the system was working in the reference house. Shading devices were also tested on a southwest facade window. Horizontal overhang had very limited benefit of less than 6% reduction in cooling energy. An external blind could save up to 12.6% of cooling energy. However, as all three shading types had a negative effect in heating season, the maximum annual saving was only 7%.
Energy environmental impact of functional units of a university building
Authors: Pedro Panagassi Forte João , Rato Vasco
Published: August 2019

This paper presents the results of a qualitative assessment of the environmental impact of a set of functional units of a university building, considering negative impacts such as the ones originated by energy, water and resource usage, as well as waste production, but also positive impacts like the ones that may be derived from teaching and learning and from research. This paper is focused on the energy –related environmental impacts which are the most significant. The assessment is performed for three evaluation scenarios: Two of these scenarios are based on the actual condition of the building facilities and its use patterns and differ from each other in the level of severity attributed to each impact criteria. The third scenario has as additional input the future condition of electric energy production through the installation of photovoltaic (PV) panels (which is in progress). According to the assessment carried out, the implementation of the PV panels may have an important contribution in reducing the environmental impact related to the use of the building.
Numerical analysis of the efficiency and energy production of the building integrated photovoltaics for various configurations
Authors: Hudișteanu Sebastian Valeriu , Popovici Cătalin George
Published: August 2019

The paper presents the analysis of the building integrated photovoltaic panels (BIPV) realized for the same photovoltaic system, placed in different locations, for the continental climate of Romania. For all studied cases, the photovoltaic (PV) system is examined in various vertical configurations, considering the integration into buildings placed in urban agglomerations, characterized by small horizontal surfaces, but generous facades. For the analyzed situations it is assumed that the PV panels are fixed in vertical position. Therefore, one of the possibilities of raising their efficiency consists in controlling the operating temperature of the photovoltaic cells. The operating parameters of the photovoltaic panels are studied in case of integration at 10 m height above the ground and the results are reported on the unit surface. The model and the functioning parameters are processed using TRNSYS software. The results are analyzed for average daily, monthly and yearly values. The results reveal some major differences obtained for the same system placed in different locations or orientations. The average efficiencies for maximum production months are lower than annual ones, while the daily values for efficiency are lowest. These values are directly dependent on the intensity of solar radiation and are negatively influenced by the operating temperature of the photovoltaic panel.
Energy Efficiency Evaluation of Different Glazing and Shading Systems in a School Building
Authors: Khalaf Mohammed , Ashrafian Touraj , Demirci Cem
Published: August 2019

The energy conversations methods and techniques take a significant role in the energy performance of the buildings. Façade and shading systems are in continuous development, and recent studies are showing the importance of implementation of such systems to reduce energy consumption and enhance the effectiveness of the building performance. School buildings are mostly being used during daytime, hence, require active use of sunlight. A measure that is taken on a school building envelope can prevent overheating and overcooling and reduce the heating and cooling energy consumption but at the same time can increase the lighting energy consumption vice versa. Thus, it is necessary to optimise the energy required for climatisation of a building with lighting energy demand. The main aim of the paper is to provide analysis for façade and shading systems applied to a school building and study the effectiveness of it on energy consumption and conservation. The case study for this paper is a typical building project designed to be located in Istanbul, Turkey and has a traditional façade system which is clear double layer windows without any shading devices. The analyses of the energy efficiency of these systems will be presented. The different glazing types and shading systems alternatives will show the most efficient one to be used as some optimised alternatives for the systems. Findings indicate that proper glazing and shading systems can reduce the needed energy for heating and lightening and thus total energy consumption of a school building significantly.
Importance of building services in ecological building assessments
Authors: Lambertz Michaela , Theißen Sebastian , Höper Jannick , Wimmer Reinhard
Published: August 2019

The new Energy Performance of Buildings Directive (EPBD) 2018 and the GebäudeEnergieGesetz (GEG) tightened the requirements for energy efficiency and the use of renewable energy sources in buildings at EU and national levels. Environmental impacts from manufacturing, dismantling and recycling of buildings are not taken into account. Green Building Certification Systems, such as the DGNB or BNB systems, are therefore the only ones that (voluntarily) set holistic, ecological requirements for buildings. Based on a Whole-Building Life Cycle Assessment, the entire building life cycle and its environmental effects are evaluated. While building services in this context are usually only included in such a simplified approach, the full scope of the produced environmental impacts are underestimated and misjudged for the reduction of emissions and other environmental impacts. This publication uses the results of a life cycle assessment of a typical office building (in Germany) to show the amount of influence building services have on environmental impacts of buildings. Furthermore the study shows an approach how the very high pro-curement and calculation effort of LCA can be reduced by linking the Building Information Modelling (BIM) Method and LCA models to enable a significantly more efficient and easier calculation process, es-pecially for building services.
Environmental impacts for polyurethane panels
Authors: Guolo Erika , Cappelletti Francesca , Romagnoni Piercarlo , Raggiotto Fabio
Published: August 2019

According to the European targets for 2030, for managing a policy of improving the environmental sustainability of buildings it is essential to assess the buildings and building components impacts both in the construction and in the utilization phases. The use of building is essential on the environmental impacts (equal to about 90%) as consequence the commitment must be aimed at reducing energy consumption and CO2 emissions of buildings during their lifetime, through correct design and proper selection of materials and technologies; above all, the use of thermal insulation materials is fundamental. A useful support tool for manufacturers and designers for the eco-design innovation of products and production processes is the LCA - Life Cycle Assessment: the assessment allows to identify and to quantify energy, consumed materials and residues released as environment impact during the processes. Comparison of the environmental impact data of the different products it is possible by adopting the EPD - Environmental Product Declarations approach, which envisages, for each group of products, the elaboration of a specific technique, the PRC - Product Category Rules. In the building sector, among the thermal insulating materials currently in use, the rigid expanded polyurethane (thermoset polymeric insulation products with a substantially closed cell structure including both polymer types based on PIR and PUR), allows to obtain excellent characteristics of very low density masses, resulting in a reduction in energy consumption deriving from transport, installation and disposal or recycling at the end of life. Numerous studies on environmental impacts during the polyurethane life cycle have shown that the amount of resources consumed for the production of polyurethane foam is amortized in the use phase of buildings thanks to the energy savings determined by thermal insulation. Very important features of polyurethane is the high durability in time (higher or equal to the life of the building). This is demonstrated following some tests of physical characterization and verification of durability of rigid polyurethane insulation panels used in different types of building and construction, without maintenance: according to the determination of thermal conductivity and of the compressive strength is proven as the values are unchanged despite the years of use (over 40 years). The paper presents the LCA evaluation of a polyurethane panel; the durability of thermal properties has been verified by experimental tests.
Dynamic thermal response of low-energy residential buildings based on in-wall measurements
Authors: Foteinaki Kyriaki , Li Rongling , Heller Alfred , Herget Christensen Morten , Rode Carsten
Published: August 2019

This study analysed the dynamic thermal response of a low-energy building using measurement data from an apartment block in Copenhagen, Denmark. Measurements were collected during February and July 2018 on space heating energy use, set-points, room air temperature and temperature from sensors integrated inside concrete elements, i.e. internal walls and ceiling, at different heights and depths. The heating system was controlled by the occupants. During February, there were unusually high set-points for some days and a regular heating pattern for some other days. Overheating was observed during July. A considerable effect of solar gain was observed both during winter and summer months. The room air temperature fluctuations were observed at a certain extent inside the concrete elements; higher in the non-load-bearing internal wall, followed by the load-bearing internal wall and lastly by the ceiling. The phenomenon of delayed thermal response of the concrete elements was observed. All internal concrete masses examined may be regarded as active elements and can contribute to the physically available heat storage potential of the building. The study provides deep insight into the thermal response of concrete elements in low-energy residential buildings, which should be considered when planning a flexible space heating energy use.
Evaluation of the Performance of a Building Envelope Constructed with Phase-Change Materials in Relation to Orientation in Different Climatic Regions
Authors: Köse Eda , Manioğlu Gülten
Published: August 2019

Minimizing the effect of climatic conditions and energy consumption in buildings are important issues to be considered in the building design process. Due to the changes in climatic conditions, there is an increase not only in the consumption of heating energy but also cooling energy. Certain passive measures to be taken primarily for the building envelope are necessary in order to reduce energy consumption. Applying a phase-change material on the surface of a building envelope is one of the new approaches for controlling heat transfer through the building envelope during the cooling period. It is known that phase-change materials, which are also considered as modern versions of thermal mass concept, can reduce the of a building’s heating and cooling energy consumption. In this study, a unit with 10m to 10m dimension with one external facade in a 3 storey building was evaluated in two cities, Istanbul and Diyarbakır, in temperate-humid and hot dry climatic regions. In order to reduce heating and cooling loads, a phase-change material was applied on the surface of the building envelope. The thickness of the phase-change material on the applied surface was increased at every step, and different building envelope alternatives were created. Heating and cooling energy consumptions were calculated for different orientations of the external facade. When calculated values are evaluated comparatively, it is seen that as the thickness of the phase-change material increases, the energy loads occurred in the unit decrease gradually. Equally, the performance of the phase-change materials varies depending on the orientation. Therefore, it is possible to determine the optimum thickness and orientation combination of the phase-change material application on a building envelope and reduce heating and cooling energy consumptions.
Energy performance of air conditioned buildings based on short-term weather forecast
Authors: Ignjatović Marko G. , Blagojević Bratislav D. , Stojiljković Mirko M. , Anđelković Aleksandar S. , Blagojević Milena B. , Mitrović Dejan M.
Published: August 2019

One of the possible ways to improve balance between building energy consumption and occupant thermal comfort in existing buildings is to use simulation-assisted operation of HVAC systems. Simulation-assisted operation can be formulated as a type of operation that implements knowledge of future disturbance acting on the building and that enables operating the systems in such a way to fulfill given goals, which in nature can often be contradictory. The most important future conditions on building energy consumption are weather parameters and occupant behavior and expectations of thermal environment. In order to achieve this type of operation, optimization methods must be applied. Methodology to create HVAC system operation strategies on a daily basis is presented. Methodology is based on using building energy performance simulation software EnergyPlus, available weather data, global sensitivity analysis, and custom developed software with particle swarm optimization method applied over the moving horizon. Global sensitivity analysis is used in order to reduce number of independent variables for the optimization process. The methodology is applied to office part of real combined-type building located in Niš, Serbia. Use of sensitivity analysis shows that the reduced number of independent variables for the optimization would lead to similar thermal comfort and energy consumption, with significant computer runtime reduction.
The new EN ISO 52000 family of standards to assess the energy performance of buildings put in practice
Authors: van Dijk Dick , Hogeling Jaap
Published: August 2019

The set of Energy Performance of Buildings (EPB) standards, developed under a mandate from the European Commission to support the EPBD, has been published in summer 2017. This set of standards enables to assess the overall energy performance of a building. A number of key EPB standards are available at global level (the EN ISO 52000 family of standards), while others are for the moment only available at European level (CEN standards). The revised European Directive on the Energy Performance of Buildings (EPBD), published in June 2018, obliges the EU Member States to describe their national calculation methodology following the ‘national annexes’ of the so called ‘overarching’ EPB standards. This will force the Member States to explain where and why they deviate from these standards and will lead to an increased recognition and promotion of the set of EPB standards across Europe and beyond. This paper provides background information and tips on how to put the EN ISO 52000 family of standards into practice.
Data-driven study on individual occupant comfort using heating setpoints and window openings in new low-energy apartments – preliminary insights
Authors: Sarran Lucile , Christensen Morten Herget , Hviid Christian Anker , Radoszynski Andrea Marin , Rode Carsten , Pinson Pierre
Published: August 2019

This work suggests a method to evaluate residential building occupants’ neutral temperature in winter based on their interaction with their heating system.

This study applies the developed method on eight new, low-energy apartments in Copenhagen, Denmark. A set of indoor temperature, heating setpoint, window opening and floor heating valve opening data was collected from mid-January to the end of April, spanning through a large part of the Danish heating season. Semi-structured interviews were performed with occupants of three of the eight apartments in order to understand their use of their heating system.

This preliminary study permits to highlight the potential and the current limitations of the proposed method, both for neutral temperature estimation as such and for applications in optimizing the energy flexibility provided by the building. This article suggests directions for further elaboration of the model. The main two influential factors highlighted here affecting setpoint adjustment are the occupants’ acceptability of temperature variation and their ability to control the heating system.
Two software tools for facilitating the choice of ground source heat pumps by stakeholders and designers
Authors: De Carli Michele , Aguirre Amaia Castelruiz , Zarrella Angelo , Cardoso Lucia , Noyé Sarah , Gast Robert , Graci Samantha , Emmi Giuseppe , Bertermann David , Müller Johannes , Galgaro Antonio , Santa Giorgia Dalla , Poletto Fabio , Mezzasalma Giulia , Contini Silvia , Urchueguía Javier , Marco Belliardi , Pasquali Riccardo , Bernardi Adriana
Published: August 2019

For promoting the diffusion of GSHP and making the technology more accessible to the general public, in the H2020 research project “CHeap and Efficient APplication of reliable Ground Source Heat exchangers and PumpS” (acronym Cheap-GSHPs) a tool for sizing these systems has been developed, as well as a Decision Support System (DSS) able to assist the user in the preliminary design of the most suitable configuration.

For all these tools a common platform has been carried out considering climatic conditions, energy demand of buildings, ground thermal properties, heat pump solutions repository, as well as renewable energy database to use in synergy with the GSHPs. Since the aims of the tools are different, there are different approaches.

The design tool is mainly addressed to designers. The calculation may be done in two ways: with a simplified method based on the ASHRAE approach and with a detailed calculation based on the numerical tool CaRM (Capacity-Resistance method).

The DSS final aim is to support decision-making, by providing the stakeholders at all the level with a series of scenario. The Cheap-GSHPs project has developed a DSS tool aimed at accelerating the decision-making process of designers and building owners as well as increasing market share of the Cheap-GSHPs technologies. Hence the DSS generates different possible solutions based on a defined general problem, identifying the optimal solution.

Both tools are presented in the paper, showing the potentialities provided by both software.
Composite silicone-SAPO-34 foams: experimental characterization for open cycle applications
Authors: Bonaccorsi Lucio , Calabrese Luigi , De Antonellis Stefano , Freni Angelo , Joppolo Cesare , Motta Mario
Published: August 2019

In this work, novel composite silicone-SAPO-34 foams have been prepared and experimentally characterized for application in desiccant open cycles. Water adsorption isotherms of several samples have been measured by a gravimetric dynamic vapour sorption analyser at 30°C and 70°C up to the relative humidity RH= 75%, representing typical process and regeneration air conditions in desiccant evaporative cooling cycles. Adsorbent foams manufactured with 20%, 40% and 60% weight fraction of SAPO-34 have been compared with the pure SAPO-34 powder. Results highlighted that the prepared foams adsorb a significant amount of water, according to the initial mass fraction of zeolite used in the compound. Moreover, the tested foams exhibited sufficiently fast water sorption rate for practical application in a desiccant open cycle system.
Study on Cross-Ventilation Performance of Residences in the Passive Town Kurobe Model Based on Measurements and CFD
Authors: Homma Yoju , Kurabuchi Takashi
Published: August 2019

The housing complex in the Passive Town Kurobe model was designed for residents to enjoy an environmentally-friendly lifestyle, and cross-ventilation was used to improve indoor thermal environment in hot seasons. To understand and maximize environmental improvements through cross-ventilation, computational fluid dynamics (CFD) simulations and measurements were carried out. It was confirmed that CFD simulation using the modified k-å model reproduced the observations with sufficient accuracy. The turbulence model used in the CFD simulations in this study was the standard k-å model, which incorporates the Durbin limiter. This model had the most accurate correspondence with the measured values. The wind catcher (WC) used to increase the cross-ventilation flow rate was found to be ineffective in the dominant wind direction. Further, it was found that if the room targeted for environmental improvement was on the upstream/downstream side, the flow rate was maximized if all windows in the room were opened.
Study on heat transfer performance of geothermal pile-foundation heat exchanger in GSHP system
Authors: Zhang Hezhi , Xu Bo , Chen Zhenqian
Published: August 2019

In order to study the heat transfer performance of geothermal pile-foundation heat exchanger in ground source heat pump system (GSHP), the physical models of pile-foundation heat exchanger and heat exchanger group were established. The heat transfer processes of pile-foundation heat exchanger and heat transfer performance was analyzed both in cooling and heating mode. To carry out the simulation of heat transfer process for 3×3 energy piles, an office building located in Nanjing was introduced. The all-year dynamic building load was calculated with DeST, including the cooling period from June to September, the heating period from December to March and two recovery periods. After ten year’s running, the average soil temperature increases in non-equilibrium condition. Study results are approximate to the actual situation and can be used as theoretical basis for the design and application of pile-foundation heat exchanger in GSHP system.
Building energy modelling for the energy performance analysis of a hospital building in various locations
Authors: Dobosi Ioan Silviu , Tanasa Cristina , Kaba Nicoleta-Elena , Retezan Adrian , Mihaila Dragos
Published: August 2019

The building sector has been identified as having the greatest energy reduction potential and therefore represents a key factor for the European Union climate change combat objectives of achieving an 80-95% greenhouse gas emissions reduction by 2050. Hospitals buildings represent 7% of the nonresidential building stock in the European Union and are responsible for approximately 10% of the total energy consumption in this sector. The design and construction of hospital buildings is a complex and challenging activity for all the involved specialists, especially when energy performance is one of the objectives. This paper discusses the energy performance simulation on an hourly basis of a new hospital building that was constructed in the city of Mioveni, Romania. At this stage of the study, the building energy model solely investigates the performance of the building envelope, without modelling the HVAC system. The complexity of the building model derives from the multitude of thermal zones depending on interior temperature and ventilation air changes conditions. Several simulations are performed investigating the heating and cooling energy need depending on the building location.
Crustacean zooplankton community in relation to physicochemical factors and phytoplankton of 13 waterbodies located in the Yangtze River delta
Authors: Wei Wenzhi , Zhuang Hang , Zhang Yingying , Wang Liufu
Published: August 2019

The relationship between crustacean zooplankton community and environmental factors remains a hot topic in eutrophication bio-monitoring subject. Most water bodies in the Yangtze River delta are mesotrophic/eutrophic, which has attracted much attention from ecologists. Nevertheless, previous studies on crustacean zooplankton community in this region only focused on their relation to physicochemical factors excluding phytoplankton. In this study, the crustacean zooplankton abundance and environmental factors (physicochemical factors and phytoplankton abundance) were investigated in Spring, Summer, Autumn and Winter in 13 waterbodies (8 lakes and 5 reservoirs) located in the Yangtze River delta. Results showed that NO2−–N and TN in Spring, SD and TP in Summer had significant difference (P < 0.05) between 8 lakes and 5 reservoirs. That may be related to microbial communities and macrophytes. All 13 studied water bodies were dominated by cyanophyta, whose Microcystis may determine the dominance of Bosmina fatalis. Moreover, eutrophic level should be in relation to the significant difference of plankton between 8 lakes and 5 reservoirs. Finally, five factors (cyanophyta, SD, WT, pH and DO) were significantly correlated with crustacean zooplankton abundance. That indicated the metabolism, reproduction, development and competitors of crustacean zooplankton were affected by these five factors. This research provided basic data of the 13 water bodies and studied the relationship between zooplankton and physicochemical factors as well as phytoplankton, providing scientific basis for the monitoring of eutrophic waterbodies located in the Yangtze river delta.