bluuebunny/crossref_metadata_2025 huggingface dataset:
A Renovation Proposal for Zero-Energy Houses: Outline of Building Planning and Evaluation of Thermal Environment
Authors: Sugano Soma , Yamaguchi Shingo , Tsuneoka Yugo , Oki Reina , Nakagawa Jun , Watanabe Naoya , Kobayashi Tatsuhiro , Tanabe Shin-ichi , Akimoto Takashi
Published: August 2019

Considering the effects of electricity shortages caused by natural disasters in Japan, residential energy efficiency is essential. In addition, excessive housing stocks in Japan have highlighted the importance of expertise in renovation methods for zero-energy houses (ZEHs). Therefore, we designed and built a ZEH as a refurbishment of steel-structure industrialized housing to acquire knowledge on ZEH design and renovation. The renovation uses a highly insulated volume against a low insulation volume, which is assumed to be an existing house. The space between the low-insulation wall facing the outside and the high-insulation wall surrounding the main living space functions as a sunroom and called a loggia. By opening and closing the inside and outside windows according to the season and time of day, the loggia functions as a passive system to reduce the air-conditioning load. In this paper, the outline of the building plan of the experimental house and the evaluation of the thermal environment are presented.
Heat and power storage using aluminium for low and zero energy buildings
Authors: Dudita Mihaela , Farchado Meryem , Englert Alexander , Carbonell Sanchez Dani , Haller Michel
Published: August 2019

A new concept for seasonal energy storage (both heat and power) for low and zero energy buildings based on an aluminium redox cycle (Al→Al3+→Al) is proposed. The main advantage of this seasonal energy storage concept is the high volumetric energy density of aluminium (21 MWh/m3), which exceeds common storage materials like coal. To charge the storage, oxidized aluminium (Al3+) is reduced to elementary aluminium (Al) in a central processing plant using renewable electricity in summer. In winter, during discharging process, the energy stored in aluminium is released in form of hydrogen and heat via the aluminium – water reaction. Hydrogen is directly converted to electricity and heat in a fuel cell. The discharging phase has been investigated using a laboratory-scale experimental setup. In optimized conditions, heat and hydrogen is reliably produced for all types of aluminium forms (grit, pellets, foil). A high efficiency of the conversion to hydrogen was obtained (>95%). The remaining challenge is to optimize the entire cycle, e.g. the aluminium recovery process via the use of climate-neutral inert electrodes.
Energy Efficiency and Cost Performance of Direct-Current Power Supply Systems in Residential Buildings by 2030s and 2050s
Authors: Yoon Gyuyoung , Sugiyama Kyoko , Yoshioka Saya , Sakai Shinji
Published: August 2019

In an effort to clarify the potential use and effectiveness of direct current (DC) power supply systems and further promote their usage, this study investigates the energy saving and cost performance characteristics of such a system for a detached house equipped with roof-mounted solar photovoltaic (PV) panels. Our evaluation considered different DC-powered appliances under different energy price conditions and made projections based on present, 2030s, and 2050s scenarios. Initial cost reductions were also considered based on assumed near-future technological developments. Our case study results show that the simple payback period is likely to be shortest in cases where DC power is only used for low-voltage appliances under present price conditions, when supplying DC power to cover interior space heating under the 2030s energy price scenario, and when covering all DC-powered appliances (including water heating) under the 2050s scenario. Taken together, these results indicate that it is desirable to set the introductory targets while projecting future energy price fluctuations and anticipating the cost reductions that will result from ongoing technological developments.
Innovative HVAC System Using an Integrated Greenhouse for a Virtual Low Energy Office Building
Authors: Lungu Catalin , Baltaretu Florin
Published: August 2019

In this paper the authors describe a HVAC innovative system using an integrated greenhouse for heating and cooling an office building. The ventilation system allows natural (night) or mechanical ventilation and the passive cooling during the summer, including cold storage in the building structure and the PCM plywood and the refrigeration energy use during the day. Natural ventilation occurs when the wind or the Venturi effect, created by the « hat » that supports the photovoltaic panels, is strong enough; otherwise, a variable speed exhaust fan mounted on top of the building is used. The plants inside the greenhouse can produce O2 under certain conditions necessary for refreshing the ventilation air. The environment of the greenhouse allows air humidification naturally, without the use of humidifiers. If the greenhouse is sufficiently insulated in winter, it can be used in the ventilation process: the air intake from offices through the greenhouse, humidified and enriched in O2 (premixed, if necessary, with fresh air) reaches the general air treatment unit, and then sent back. The process is similar in the summer, but without recirculation, due to the humidity of the air extracted from offices. Stale air humidification enhances the thermal transfer process from the desiccant collector.
Parametric simulation study for green roof retrofit over high performance solar house prototype “EFdeN Signature”
Authors: BAICEANU Mihai , CATALINA Tiberiu
Published: August 2019

The advantages of green roofs are well documented, ranging from heat island reduction, thermal comfort, air quality, stormwater management and energy savings for buildings. However, it has been shown that green roof retrofits are more effective in old, low efficiency buildings. This paper studies the possibility of retrofitting a high efficiency solar house with a green roof system being partially shaded, optimising its characteristics by means of parametric simulation. The input variables of the green roof system are: growth medium thickness, LAI (leaf area index) and height of plants. The output variables by which the different green roof systems are compared are: annual energy demand for heating and for cooling. The study concluded that the average reductions of energy consumption when retrofitting an efficient building with an extensive green roof are of 1.01% for heating and 4.61% for cooling, but optimising parameters (low LAI in winter, high LAI and height of plants in summer) can get reductions to 1.55% for cooling and 5.95% for cooling.
The ‘Mind the Gap’ project: Investigating the difference, in performance, between design and the building ‘in-use’
Authors: Lewry Andy , Hadi Mindy , Bennett Jaie , Peters Richard
Published: August 2019

We have the ability to design and construct high performance buildings; and the knowledge and skills to operate them in an effective and efficient manner — so why does it not happen? The underpinning reasons for this gap in performance are generally unknown; there is a lot of speculation and hypothesis but little investigation and hard evidence. The ‘Mind the Gap’ project aims to collect evidence from typical exemplars of office buildings investigate the reasons for their performance and determine the underpinning causes. The first phase of the project will produce a methodology based on the learnings from five trial buildings and then rolled out in a second phase over a larger number of buildings. This paper presents some initial data and findings.
Comparative Analysis for Renovation of an air Heating and Cooling System from a Romanian Administrative Building
Authors: Răzvan Calotă , Robert Titi , Madalina Nichita , Anica Ilie , Alina Girip
Published: August 2019

In this paper, the authors determine the energy consumption for heating and air conditioning of an administrative building located in the second climatic area, in Romania. The heating and cooling system is provided with fan coils, and the fresh air is supplied by an AHU. The aim is to identify the best solution from 3 proposed heating and cooling systems that can be applied in order to improve the living conditions, namely: boiler with solid fuel (wood) or gas and chiller with mechanical vapor compression (VCM); reversible heat pump; boiler with solid fuel (wood) or gas and absorption chiller type LiBr-H2O driven by solar energy. The goal of the study is to select one of the three solutions which involves minimum investment and exploitation costs.
Discussion of Optimized Operation of a nearly Zero Energy Building’s Energy System in China
Authors: Li H. , Yu Z. , Wu J. , Xu W. , Zhang S.
Published: August 2019

A nearly zero energy office building was established in north China as a demonstration project to explore the nearly zero energy building’s technical system in China. Not only the building itself, but also the energy system was designed with careful consideration to satisfy its high positioning and experimental verification attributes. Energy system in this building is completely finished and extremely challenging. Two kinds of renewable energy system worked together to serve the building, as operation modes varied accordingly to outside weather conditions. Depending on different system combinations, 4 strategies were found, and in this article, 4 of them are discussed. Energy consumption and system performance were compared and analysed to find an optimized operation.
Energy Performance Evaluation of Hybrid VRF Systems Based on Japanese Government-Designated Method
Authors: Kawase Tokimi , Hashimoto Atsushi , Yasuda Ken , Nobe Tatsuo
Published: August 2019

Variable Refrigerant Flow Rate (VRF) System is used as air-conditioning systems in small and medium-sized buildings in Japan. Traditionally, the two most common types of VRF systems are electric motor driven VRF Systems (EHP) and gas engine driven VRF Systems (GHP). However, in recent years’ society is increasingly demanding energy saving and the best energy mix. This requires an air-conditioning system that has energy flexibly depending on the application and situation. As a result, a hybrid airconditioning system (called Hybrid VRF System) that satisfies theses need has been developed. The developed system can operate according to energy price and usage situations by connecting GHP and EHP with one refrigerant cycle. In recent years, a Hybrid VRF Systems have been used for small to mediumsized buildings. In this paper, the author evaluated the performance of an integrated Hybrid VRF System based on the energy evaluation method prescribed by Japanese law.
CLIMA 2019-Modelling study on pipe-encapsulated PCM wall system for building insulation and active heat removal
Authors: Yan Tian , Xu Xinhua , Gao Jiajia
Published: August 2019

Phase change material (PCM) can be used in building envelope for heat insulation and energy-saving. However, the energy-saving effect of the PCM wall system is limited in summer since the PCM storing heat in the daytime will become a secondary heat source and release heat into the room again at night. This paper proposed a novel pipe-encapsulated PCM wall system. It integrates phase change technology and nocturnal radiation cooling technology together to realize building insulation and active heat removal. A simulation platform is established for the thermal performance simulation of this wall system. It mainly includes the simplified pipe-encapsulated PCM wall model and nocturnal radiation model. The simplified wall model includes the 5R2C wall model, 4R2C PCM model and 2R1C pipe model. The model parameters are identified and the model is also validated with good accuracy. Based on this platform, the thermal performance of a light weight room with pipe-encapsulated PCM wall system in Wuhan is simulated. About 50%-60% of heat from the outdoor environment can be conserved by the pipe-encapsulated PCM wall, and 50% of that can be removed by the radiant cooler at night. Results show the pipe-encapsulated PCM wall system has good thermal performance for light weight building.
Performance analysis of an active diffuser in mixing ventilation for cell office by using numerical approach
Authors: Rabani Mehrdad , Madessa Habtamu B. , Nord Natasa , Schild Peter
Published: August 2019

Energy efficiency in buildings is nowadays considered as an essential step to reduce CO2 emissions and energy utilization. At the same time, new technologies such as building space heating using active air heating has simplified the heating system without any need for backup heating system. This study investigated the thermal stratification of mixing ventilation system equipped with a radial active supply diffuser for space heating of an office room designed according to the Norwegian passive house standard by using Star-CCM+. Simulations were performed for different supply airflow rates with corresponding slot openings of the active diffuser at different outdoor conditions for winter season. The combined effect of the supply airflow rate and the outdoor air temperature were also described in the form of Archimedes number (Ar). The results showed that adopting active diffuser could avoid the temperature stratification for all the simulated cases by preserving the throw length of supply jet. In addition, the lowest temperature effectiveness of 38% occurred when a high supply temperature was used in the coldest day. Furthermore, with the supply temperature 24 °C, the airflow rate 49.4 l/s at the outdoor temperature -15 °C would result in a favorable average of PMV ⁓ 0.497.
Optimal design of an indoor environment using an adjoint RNG k-ε turbulence model
Authors: Zhao Xingwang , Chen Qingyan
Published: August 2019

The computational fluid dynamics (CFD)-based adjoint method can determine design variables of an indoor environment according to the optimal design objective, such as minimal predicted mean vote (PMV) for thermal comfort. The method calculates the gradient of the objective function over the design variables so that the objective function can be minimized along the fastest direction using an optimization algorithm. Since the RNG k-ε model is the most popular model used in CFD, the corresponding adjoint equations of the turbulence model should be solved during the design process, rather than the “frozen turbulence” assumption used in the existing approach. This investigation developed adjoint equations for the RNG k-ε turbulence model and applied it to a two-dimensional ventilated cavity. Design processes with the adjoint RNG k-ε turbulence model led to a near-zero design function for the cavity case, while that one with the RNG k-ε turbulence model did not.
A study of the nonlinearity of a building thermal behavior based on metamodeling
Authors: Jaffal Issa , Inard Christian
Published: August 2019

In this work, we present a study of the nonlinearity of building thermal behavior based on a metamodel for cooling energy needs. We studied the nonlinearity of the thermal behavior of an office. The building quadratic behavior and interactions between its components were analyzed based on the metamodel coefficients. The metamodel was fitted with a reduced number of dynamic simulations. The nonlinearity was first assessed as function of the mean outdoor air temperature in fifteen typical European climates and then as function of the internal heat gains for the coldest and hottest climates. The metamodel provided highly accurate results with fast calculation time. However, a higher accuracy was generally obtained for hot climates, high internal heat gains and lightweight thermal mass. Conversely, the nonlinearity of thermal behavior was accentuated in cold climates and with low internal heat gains. Moreover, the interactions between the building components were found to be more influential on cooling energy needs than quadratic behavior. We propose a classification of thermal behavior into three regimes: Highly nonlinear when the energy needs are close to zero; intermediate with decreasing nonlinearities that can be expressed by power functions; and finally, a quasi-linear regime with almost-steady nonlinearities.
Investigation of a multizone building with HVAC system using a coupled thermal and airflow model
Authors: Eydner Matthias , Toufek Bamo , Henzler Tobias , Stergiaropoulos Konstantinos
Published: August 2019

In building energy simulations, the air infiltration and interzonal airflow are generally either not considered or calculated oversimplified. However, the effects of air infiltration and building airflow have an impact on the thermal comfort and the building’s energy load. The various zones in multi-zone buildings, the operation of windows, doors and mechanical ventilation make the system’s analysis complex and challenging. Building airflow affects pressure, temperature and moisture differences. Therefore, this study investigate the airflow inside a multizone building with changing user behavior, using a coupled building and system energy simulation. A decentralized air-only HVAC system provides the ventilation system with a control strategy, which variably adapts the airflow to the load in the individual zones. The effects of the air infiltration, interzonal airflow and mechanical ventilation in the building are investigated with a node and link network in TRNSYS using the airflow model TRNFLOW (COMIS). Investigating different variations of the ventilation rates and building’s airtightnesses, the results are shown by comparison with a reference model without airflow simulation. Finally, this study shows a comprehensive approach at low computational costs, determining the air quality, the thermal conditions and the airflow in a multizone building using an HVAC system.
Dynamic simulation of indirect air conditioning systems with optimized computational time
Authors: Ablanque Nicolás , Torras Santiago , Oliet Carles , Rigola Joaquim , Pérez-Segarra Carlos-David
Published: August 2019

The simulation of HVAC systems is a powerful tool to improve the energy efficiency in buildings. The modelling of such systems faces several obstacles due to both the physical phenomenology present and the numerical resolution difficulties. The present work is an attempt to develop a robust, fast, and accurate model for HVAC systems that can interact with the other relevant systems involved in buildings thermal management. The whole system model has been developed in the form of libraries under the Modelica language to exploit its advantageous characteristics: object-oriented programming, equationbased modelling, and handling of multi-physics. The global resolution is carried out dynamically so that not only steady-state predictions can be conducted but also control strategies can be studied over meaningful periods of time. This latter aspect is crucial for optimizing energy savings. The libraries include models for all the system individual components such as pumps, compressors or heat exchangers (operating with twophase flows and/or moist air) and also models assemblies to account for vapour compression units and liquid circuits. An illustrative example of an indirect air conditioning system is detailed in the present work in order to highlight the model potential.
Analysis of the need of detailed modelling for the assessment of indoor air quality in residential buildings
Authors: Cony-Renaud-Salis Louis , Belhaj Nouamane , Ramalho Olivier , Abadie Marc
Published: August 2019

Home represents an important part of the time spent indoors and is the emblematic place of a family need, e.g. well-being, comfort and safety. In France, health agencies provide information and raise the awareness of the public on health risks and on factors likely to affect the quality of indoor air. However, indoor air quality remains difficult to assess for health investigators. A solution would be to resort to field measurements, but they are expensive and hard to apply to a large-scale population when considering the numerous pollutants found indoors. Therefore, numerical simulation represents a good alternative when accurate and realistic input data are used. We already designed such a model of a dwelling prototype using a type 98 coupling procedure between CONTAM (airflow rates and pollutants concentration determination) and TRNSYS (thermal and moisture calculation). We paid a lot of attention to the details that we thought were important: dwelling multi-zonal representation, envelope airtightness, ventilation system elements (pressure driven inlet and outlet, ducts, fan characteristics), presence of furniture, people activity and location… Nevertheless, the design of this simulation requires a very specific care. This very last point naturally induces a debate: is it necessary to design the simulation to be as accurate and realistic as it actually is, or will a simpler model provide similar results? In this study, we aim to answer that question by evaluating the sensitivity of the ULR-IAQ multipollutant index, defined in a previous study, to different levels of modelling complexity.
A set of comprehensive indicators to assess energy flexibility: a case study for residential buildings
Authors: D’Ettorre Francesco , Brennenstuhl Marcus , Kathirgamanathan Anjukan , De Rosa Mattia , Yadack Malcolm , Eicker Ursula , Finn Donal P.
Published: August 2019

The increasing share of renewable energy sources in the power industry poses challenges for grid management due to the stochastic nature of their production. Besides the traditional supplyside regulation, grid flexibility can also be provided by the demand side. Demand-Response is an attractive approach based on adapting user demand profiles to match grid supply constraints. Nevertheless, defining the flexibility potential related to buildings is not straightforward and continues to pose challenges. Commonly accepted and standardized indicators for quantifying flexibility are still missing. The present paper proposes a new quantification methodology to assess the energy flexibility of a residential building. A set of comprehensive indicators capturing three key elements of building energy flexibility for demand response, notably, capacity, change in power consumption and cost of the demand response action have been identified. The proposed methodology is applied to a residential building, whose heating system is controlled by means of a model predictive control algorithm. The building model is developed on the basis of the experimental data collected in the framework of a European Commission supported H2020 research project Sim4Blocks, which deals with the implementation of demand response in building clusters. The optimal control problem has been investigated by means of mixed-integer linear programming approach. Real time prices are considered as external signals from the grid driving the DR actions. Results show that the proposed indicators, presented in the form of daily performance maps, allow to effectively assess the energy flexibility potential through its main dimensions and can be easily used either by an end-user or a grid-operator perspective to identify day by day the best DR action to be implemented.
CFD simulation analysis on integrated operation of range-hood and make-up air supply for cooking-generated particulate matter
Authors: Kim Hyungkeun , Kang Kyungmo , Lee Yun-Gyu , Kim Taeyeon
Published: August 2019

One of the most important problems of cooking-generated particulate matter (PM) is that it rapidly disperses when the range hood is in operation during cooking. To improve the performance of the range hood and prevent the dispersion of PM, a supply of make-up air equivalent to the airflow rate of the range hood should be provided. In this regard, we place an auxiliary supply system as a make-up supply to solve such problems. The objective of this study is to evaluate the performance of the make-up air supply system and the range hood. To evaluate this system, several case studies were performed involving CFD simulations. The auxiliary supply system is optimized through three types of variables (size of diffuser, distance from the source, and flow angle). An increase in the length of the diffuser causes PM dispersion to decrease. The installation of the diffuser at a certain distance from the emission source is effective in preventing dispersion of cooking-generated PM. In the building analyzed in this study, supplying the make-up air at an angle of 10° was observed to be most effective.
Dynamic design model of displacement ventilation
Authors: Lastovets Natalia , Kosonen Risto , Jokisalo Juha , Kilpeläinen Simo
Published: August 2019

An accurate temperature gradient calculation is essential for displacement ventilation (DV) system design, since it directly relates to the calculation of the required supply air flow rate. Inaccurate temperature prediction can cause the poor thermal comfort and w sizing of the ventilation and cooling systems. Several simplified nodal models were developed and implemented in the various building simulation software to estimate the temperature stratification in rooms with DV. Recent studies reveal that the multi-nodal models provide the most accurate temperature gradient prediction. However, the most building simulation software uses the air models with only one air node. The present study introduces the dynamic temperature gradient model for DV and investigates the effect of thermal mass on the temperature stratification. The model was validated with the experimental results of the lecture room with displacement ventilation. The room air temperature measurements were conducted during three weeks at 20 different heights. The supply air temperature and occupancy rate were recorded during each scheduled lecture. The developed dynamic nodal model is able to accurately calculate the air temperatures in occupied zone. The effect of the thermal mass and varied heat loads on the indoor air temperature stratification is analysed for the lecture room with DV.
Model predictive control for buildings with active one-pipe hydronic heating
Authors: Dostal Jiri , Baumelt Tomas
Published: August 2019

One-pipe hydronic heating systems in their active (decentralized pumping) form promise great benefits over traditional two-pipe variable volume systems, and even more so over variable air volume systems. The heat exchanger units are connected in series, which presents its challenges and opportunities. This paper presents a model predictive controller capable of harnessing as many benefits as there is in the system when used in a building. A case study on a small office building illustrates the capabilities and validates the concept.
Occupant behaviour and thermal comfort in buildings: Monitoring the end user
Authors: Visser Loes , Kingma Boris , Willems Eric , Broers Wendy , Loomans Marcel , Schellen Henk , op’t Veld Peter , Marken Lichtenbelt Wouter van
Published: August 2019

Studies indicate that the energy performance gap between real and calculated energy use can be explained for 80% by occupant behaviour. This human factor may be composed of routine and thermoregulatory behaviour. When occupants do not feel comfortable due to high or low operative temperatures and resulting high or low skin temperatures, they are likely to exhibit thermoregulatory behaviour. The aim of this study is to monitor and understand this thermoregulatory behaviour of the occupant. This is a detailed study of two females living in a rowhouse in the city of Heerlen (Netherlands). During a monitoring period of three weeks over a time span of three months the following parameters were monitored: activity level, clothing, micro climate, skin temperatures and thermal comfort and sensation. Their micro climate was measured at five positions on the body to assess exposed near body conditions and skin temperature. Every two hours they filled in a questionnaire regarding their thermal comfort and sensation level (7-point scale), clothing, activities and thermoregulatory behaviour. The most comfortable (optimal) temperature was calculated for each person by adopting a biophysical model, a thermoneutral zone model. This study shows unique indivual comfort patterns in relation to ambient conditions. An example is given how this information can be used to calculate the buildings energy comsumption.
The Effect of the Heating System on the Occupant’s Thermal Comfort and Optimum Room Air Temperature
Authors: Dederová Kohoutková Alžběta , Horváthová Jana , Kny Martin , Nehasil Ondřej
Published: August 2019

Experiments were repetitively held in the laboratory of a research centre on a group of twenty-four participants for four different heating systems. All were of same age and wore similar clothing. Half were male and half female. During these 288 experiments objective indoor environment parameters (air temperature, globe temperature, relative humidity and air velocity) were measured, as well as subjective parameters (body surface temperatures) during low-intensity physical activity. Participant´s satisfaction with the thermal comfort was observed. They evaluated their perceptions on questionnaires. The thermal comfort of participants and influence of the type of heating system was evaluated based on these answers. On the basis of these subjective perceptions, acceptable air temperatures for control of various heating systems were evaluated.
Graphical visualization of behavioural patterns in relation to indoor environment quality and energy use
Authors: Lițiu Andrei Vladimir , Barthelmes Verena Marie , Becchio Cristina , Fabi Valentina , Tarantini Mariantonietta , Vergerio Giulia , Corgnati Stefano Paolo , Martinac Ivo
Published: August 2019

In this paper, the authors provide a general overview on the methodological framework behind the monitoring and evaluation strategies of Mobistyle project that are used as reference for the demonstration cases. The strategies identify parameters that need to be evaluated during several phases regarding the impact (energy, IEQ, health, behavioural patterns) and the strategy (effectiveness of the process) of the project, and how these parameters can be numerically evaluated. In particular, the paper focuses on the graphical visualization method for behavioural patterns analysis in relation to indoor environment quality and energy use. The proposed approach is illustrated based on measured data from one Mobistyle Project case study i.e. a hotel for long term stay located in Turin, Italy.
OpEEr – Optimising the energy efficiency of buildings through individual room temperature control
Authors: Mojic Igor , Haller Michel
Published: August 2019

In Switzerland, the standard SIA 384/1 (based on SN EN 12828) does not require individual room temperature control for new buildings or very well refurbished buildings with space heating supply temperatures below 30 °C. This is justified by the so-called “self-regulating effect”, which means that when the room temperature increases the heat input into the room is reduced due to the decreasing temperature difference between the hydronic heating system and the room. According to the new regulations of the Swiss cantons (MuKEn 2014), at least a reference room temperature control is prescribed. However, it is still unclear whether and when the individual cantons will adopt this regulation. This study compares the three most common variants for room temperature control using dynamic simulations. The simulations show that the self-regulating effect cannot sufficiently reduce the heat input into the room, and that a reference room control is not only energetically more efficient, but also economically more attractive. Individual room control performs better than reference room control in terms of comfort and final energy consumption. A further finding from the project is that the heat requirement for an apartment of a multi storey building depends strongly on the temperatures with which the storeys below and above are heated. Under certain circumstances, the ratio of the total building heat requirement for an apartment of the storey in the middle can be reduced from 20% to 1%. In the project, recommendations for building owners and authorities regarding room temperature control were worked out.
Contextual and behavioural factors influencing human-building interaction in university offices: a cross-cultural comparison
Authors: d’Oca Simona , Podjed Dan , Vetršek Jure , Dolinšek Slavko , Veld Peter op’t
Published: August 2019

This paper presents the outcomes of a survey questionnaire deployed in the buildings of the Faculty of Economics (FE) and Faculty of Arts (FA) of the University of Ljubljana (UL), Slovenia, in a cross-cultural comparison of previous results gathered in three analogous university buildings in Italy. Objective of this study, which was in the Slovenian cases supplemented by qualitative (ethnographic) research approaches, is to provide comparative insights into four key research objectives: (1) cultural, contextual and socio-demographic factors regarding interaction with shared environmental controls (such as adjustable thermostats, operable windows, blinds and shades, and artificial lighting), (2) group dynamics such as perceived social norms, attitudes, and intention to share controls, (3) occupant’s self-assessed ease of use and knowledge of how to operate control systems, and (4) occupant’s perceived comfort, satisfaction, and productivity. First cross-country comparison analysis implies that practices and habits on how occupants interact within public buildings present distinct patterns within EU countries. More broadly, this study attempts to confirm the validity of the mixed methods research, combining quantitative and qualitative inquiry, and the survey instrument, as a way to validate the robustness of outcomes for future studies. In addition, the paper aims at illustrating why and how insights from different fields of social science, including psychology, sociology and anthropology, can foster innovation in the area of adoption and acceptance of technologies in shared spaces. The final objective of the study is enhancing attractiveness and effectiveness of ICT solutions for increasing user awareness and information provisions targeting energy savings, office workers’ productivity and reduced operational energy costs, in the context of the EU H2020 MOBISTYLE project.
Interlinking the effect of thermal mass and temperature control strategies in dwellings
Authors: Verbeke Stijn , Audenaert Amaryllis , Verhaert Ivan
Published: August 2019

Exposed heavyweight constructions with a high specific heat capacity can dampen and delay transient heat flows in buildings. This paper explores the dynamic effects of various construction assemblies and explores the effect of different temperature control strategies in relation to the thermal mass. The thermal inertia of a building not only affects the pace of heating up a thermal zone, but also the temperature set-back that can be attained with an intermittent heating regime, and thus the setpoints of control regimes.

Based on a simulation study, it is demonstrated that the impact of the thermal mass on the heating demand of dwellings is rather limited in a temperate climate. Lightweight timber frame construction can display an annual heating energy demand of up to 6.6% higher compared to a heavy mass concrete and limestone construction in case of fixed thermostat setpoints. If a different control strategy with a highly intermittent thermostat schedule is implemented, the energy use of the lightweight construction can conversely have a lower heating energy expenditure, with a reduction of up to -4.5%. Modelling assumptions on the HVAC system capacity, the timing of the start-up moment of intermittent heating and the type of thermostat control – either based on air temperature or operative temperature – can have a significant influence on the simulation outcomes. Depending on the modelling assumptions and temperature control strategies implemented, the detailed dynamic simulations display that heavy mass buildings will not necessarily yield a lower heating demand as would be predicted by simplified monthly quasi-steady state calculations. In general, it is advocated that a better understanding of control strategies and resulting comfort sensations is required in building design and performance simulation.
An algorithmic module toolkit to support quality management for building performance
Authors: Mehnert Jan , Reiß Dirk , Plesser Stefan , Hannen Matthias
Published: August 2019

Data from building automation systems is so far used for the operation of building systems and components only. The following work shows how this data can be used to enhance the building’s performance by strategically detecting potential sources for building optimization. With this method, faults and optimization potentials of the building operation can be detected; thus, the quality gap regarding efficiency and comfort aspects between design and operation can then be reduced. Furthermore, the intelligent use of data enables the realization of economic savings to support facility management with regards to increasingly complex HVAC systems. Effective quality management – rapid, transparent and cost effective – is carried out with the aid of digital methods, which are already state of the art in other industries.
climify.org: an online solution for easy control and monitoring of the indoor environment
Authors: Calì Davide , Kindler Ekkart , Ebrahimy Razgar , Bacher Peder , Hu Kevin , Lind Østrup Michelle , Bachalarz Magnus , Madsen Henrik
Published: August 2019

Real energy performance of new and retrofitted buildings often consistently differs from expectations. While occupants might complain about poor indoor climate, the energy use in such buildings is often higher than expected, leading to the well-known phenomenon called “Energy Performance Gap”. In the past years, monitoring of buildings, both in terms of energy use and indoor climate conditions, was realised mostly for office buildings only, and at high financial costs. However, the exponential growth in availability of IoT devices, over the last years, opens now new scenarios for low-cost monitoring and control solutions of buildings. Yet, modern IoT devices are often only accessible online through the vendors’ software, although some devices make use of open communication protocols and can, therefore, be connected to open platforms such as openHAB. However, the use of open platforms is still connected to a big efforts for many final users. We, therefore, propose climify.org, an open platform for plug and play connection of IoT sensors and actuators, for easy monitoring and controlling of buildings and buildings’ HVAC systems. The platform climify.org offers, at time of writing, three main applications. The first application is an IoT device installation app, to be used on portable devices (e.g. mobile phones or tablets of system administrators): this app allows easily installing and locating a sensor or an actuator, within a building. The second application is an online service for data visualisation and HVAC control: while the monitoring data can be plotted, the service offers several data evaluation methods; moreover, the settings of the connected actuators can be modified and controlled. The third application can be installed on portable devices (mobile phones and tablets of buildings’ occupants) and allows occupants to provide feedback on their perception of the indoor climate through several questionnaires’ formats. Through the three applications developed within climify.org, we aim at providing the best indoor climate and the lowest energy use through a low-cost solution.
Some aspects of controlling radiant and convective cooling systems
Authors: Arghand Taha , Dalenbäck Jan-Olof , Trüschel Anders , Javed Saqib
Published: August 2019

Designing appropriate control systems for radiant heating and cooling terminals entails an understanding of their dynamic behaviour. This study experimentally investigates the dynamic response of a room with convective and radiant cooling systems. The experiments were performed in a 12.6 m2 large test room outfitted as a single-office room. The main cooling system was radiant ceiling panels which covered 70% of the ceiling area. The thermal performance of the radiant system was compared to that of a fan-coil unit (FCU). The results from the step response test showed that the time constant of the room for the radiant system was shorter than for the convective one, indicating faster changes in room temperature by the radiant system. Furthermore, controlling the FCU with similar control system tuned for ceiling panels increased the hysteresis gap in the room air temperature from 0.4 K to 0.8 K. This indicates that control systems for low-mass radiant systems and convective systems might be applied to each other, but on-site tuning is required to omit the offset (persistent error). In this study, controlling room temperature with ceiling panels did not benefit from using an operative temperature sensor to provide feedback signal to the control system. However, the pump energy use was moderately decreased by 14%.
Identification of Energy Use Time Patterns of Occupied Dwellings using Smart Meter Data
Authors: Himpe Eline , Janssens Arnold
Published: August 2019

The increasing application of smart and digital energy meters leads to an increasing availability of frequent -e.g. hourly- and long-term measurements of the actual energy use in occupied buildings. In the resulting energy use time series, the diurnal fluctuations in energy use are recognised and similarities between diurnal profiles for various days are observed. These recurring profiles are called energy use time patterns and they are a result of various phenomena, such as patterns in the building use, occupational schedules, settings of the system control, short-term weather dynamics etc. These energy use time patterns can provide a better understanding of the energy use, which is useful in many fields including energy feedback, fault detection and energy auditing. In order to identify and characterise energy use time patterns for large data-sets, an automated approach is needed. This paper proposes a methodology for automated mathematical recognition of energy use time patterns based on cluster analysis. Secondly, a methodology to characterise the identified patterns in function of external variables is proposed, using classification analysis techniques. The methodologies allow an automated identification and characterization of energy use time patterns, allowing a better understanding of the variations and changes in building energy use and their relation to weather conditions and calendar aspects.
Forecasting of Three Components of Solar irradiation for Building Applications
Authors: Notton Gilles , Voyant Cyril , Fouilloy Alexis , Duchaud Jean Laurent , Nivet Marie Laure
Published: August 2019

Solar energy and the concept of passive architecture and Net Zero Energy buildings are being increased. For an optimal management of the building energy, a Model Predictive Control is generally used but requires an accurate building model and weather forecast. For a more reliable modelling, the knowledge of the global solar irradiation is not sufficient; three methods, smart persistence, artificial neural network and random forest, are compared to forecast the three components of solar irradiation measured on the site with a high meteorological variability. Hourly solar irradiations are forecasted for time horizons from h+1 to h+6. The random forest method (RF) is the most efficient and the accuracy of forecasts are in term of nRMSE, from 19.65% for h+1 to 27.78% for h+6 for global horizontal irradiation, from 34.11% for h+1 to 49.08% for h+6 for beam normal irradiation, from 35.08% for h+1 to 49.14% for h+6 for diffuse horizontal irradiation. The improvement brought by the use of RF compared to the two other methods increases with the forecasting horizon. A seasonal study is realized and shows that the forecasting during spring and autumn is less reliable than during winter and summer due to a higher meteorological variability.
A NILM method for cooling load disaggregation based on artificial neural network
Authors: Xiao Ziwei , Yuan Jiaqi , Gang Wenjie , Zhang Chong , Xu Xinhua
Published: August 2019

The demand of building energy management has increased due to high energy saving potentials. Load monitor and disaggregation can provide useful information for building energy management systems with detailed and individual loads of the building, so corresponding energy efficient measures can be taken to reduce the energy consumption of buildings. The technique is investigated widely in residential buildings known as Non-Intrusive Load Monitoring (NILM). However, relevant studies are not sufficient for non-residential buildings, especially for the cooling loads. This paper proposes a NILM method for cooling load disaggregation using artificial neural network. The cooling load is disaggregated into four categories: building envelope load, occupant load, equipment load and fresh air load. Two approaches are used to realize the load disaggregation: one is based on the Fourier transfer of the cooling loads, the other takes the cooling load, dry-bulb temperature and humidity of outdoor air, and time as inputs. By implementing the methods in a metro station, the performance of the proposed method can be obtained. Results show that both approaches can realize the load disaggregation accurately, with a RMSE less than 11.2. The second approach is recommended with a higher accuracy.
Development of zero energy flexible unit with no Infrastructure for disaster and disaster response
Authors: Park Beungyong , Cho Jinkyun , Jeong Yongdae , Lee Sangmoon
Published: August 2019

In this paper a new kind of unit-prefabricated building is shown. The unit-prefabricated buildings are made up living unit, energy unit, water unit. The each unit was adapted new combine structure function as a high flexible design type. Moreover the design trend implemented the energy insulation, Solar PV panels, Energy storage system which are maintained for zero energy buildings. We made a prototype for zero energy flexible residential unit. The first step, we was evaluated physical performance and living environment, insulation, airtightness, thermal environmental, acoustic performance. The second step we was evaluated energy performance building to design heating and cooling system to combined PV, ESS system in the different plan type, and climate. As a results, The insulation performance wall was 0.18 W/(m2•K). The results of air-tightness was 12.13 ACH@50 (1/h). Further research we develop the structure and construction technology for zero energy flexible unit. To designed the high performance energy performance for zero energy building in the natural disaster.
The influence of the combined effect of draught and radiant thermal asymmetry on human performance
Authors: András-Tövissi Balázs , Kajtár László , Wargocki Pawel
Published: August 2019

Currently, there are studies which show the separate effect of the local discomfort parameters such as the draught and radiant thermal asymmetry. However, no studies have been conducted to find out the combined effect of the before mentioned two discomfort parameters on human performance. In order to fill this gap, a 17 months experiment was performed at the Budapest University of Technology and Economics. Throughout the experiment twenty human subjects (ten women and ten men) performed different cognitive tests and responded to questionnaires. Two different draught rates and five different radiant thermal asymmetry values were imposed in the Macskásy climate chamber, where the experiment took place. The results show the consequence of the combined effect of draught and radiant thermal asymmetry on the human performance.