bluuebunny/crossref_metadata_2025 huggingface dataset:
Optimization of emission reducing energy retrofits in Finnish apartment buildings
Authors: Hirvonen Janne , Jokisalo Juha , Heljo Juhani , Kosonen Risto
Published: August 2019

This study examined the cost-optimality of energy renovation on Finnish apartment buildings of different ages, built according to different energy performance requirements. Multi-objective optimization was utilized to minimize both CO2 emissions and life cycle cost (LCC). IDA-ICE simulations were performed to obtain the hourly heating demand of the buildings. Four building age classes and three heating systems (district heating, exhaust air heat pump and ground-source heat pump) were separately optimized. With district heating, it was possible to reduce emissions by 11%, while also reducing LCC. With heat pumps cost-savings could be achieved while reducing emissions by over 49%. With maximal (not cost-effective) investments, emissions could be reduced by more than 70% in all examined cases. In all cases, the cheapest solutions included solar electricity and sewage heat recovery. In old buildings, window upgrades and additional roof insulation were cost-effective. In new buildings, demand-based ventilation was included in all optimal solutions.
Energy conservation by retrofitting of dwellings
Authors: Sánka Imrich , Petráš Dušan
Published: August 2019

This article investigates the impact of energy renovation on the indoor environmental quality of apartment building during heating season. The study was performed in one residential building before and after its renovation. Energy auditing and classification of the selected building into energy classes were carried out. Additionally, evaluation of indoor air quality was performed using objective measurements and subjective survey. Thermal environment and concentration of CO2 was measured in bedrooms. Higher concentrations of CO2 was observed in the residential building after its renovation. The concentrations of CO2, in some cases exceeded the recommended maximum limits, especially after implementing of energy saving measures on the building. The average air exchange rate was visible higher before renovation of the building. The current study indicates that large-scale of renovations may reduce the quality of the indoor environment in many apartments, especially in the winter season.
Analysing the Energy Efficiency Renovation Rates in the Dutch Residential Sector
Authors: Ebrahimigharehbaghi Shima , Filippidou Faidra , van den Brom Paula , Qian Queena k. , Visscher Henk J.
Published: August 2019

The housing stock has a major share in energy consumption and CO2emissions in the Netherlands. CO2emissions increased 2.5% year-on-year in the first quarter of 2018. Higher CO2emissions were principally due to raised gas consumption for heating in the residential and service sector1. Energy efficiency renovations can contribute considerably in reducing energy consumption and achieving the EU and national energy efficiency targets. However, based on recent research2, the renovation rates in the Dutch social housing sector are not adequate to achieve the energy efficiency targets. Moreover, the deep renovation rates are almost negligible in this sector. The Dutch housing stock consists of the owner-occupied sector and rental sector (social housing and private rental houses) with shares equal to 69.4% and 30.6%, respectively. Considering the major share of the housing sector in energy consumption, the aim of the current study is to evaluate and compare the renovation rates in these sectors and the potential contribution of each one in achieving the energy efficiency targets. By renovation rate, we mean the percentage changes in the number of the identical houses moving from one energy label to the more efficient energy labels. The Netherlands Enterprise Agency (RVO) and Statistics Netherlands (CBS) databases are used to conduct the statistical analysis. The results show that the renovation rates are almost the same in these three sectors, despite the expectation of much higher renovation rates in the social housing sector.
Life Cycle Energy Assessment of a School Building under Envelope Retrofit: An Approach towards Environmental Impact Reduction
Authors: Moazzen Nazanin , Karagüler Mustafa Erkan , Ashrafian Touraj
Published: August 2019

Energy efficiency of existing buildings is a concept to manage and restrain the growth in energy consumption and one of the crucial issues due to the magnitude of the sector. Educational buildings are in charge of about 15% of the total energy consumption of the non-residential building sector. However, not only operational but also embodied energy of a building should be reduced to get the overall benefits of energy efficiency, where, using energy efficient architectural measures and low emitting materials during every retrofit action can be a logical step. The majority of buildings in Turkey and EU was built earlier than the development of the energy efficiency in the construction sector, hence, without energy retrofit, consume an enormous amount of energy that can be averted significantly by the implementation of some even not advanced retrofit measures. Furthermore, demolishing of a building to construct a new one is not a rational approach concerning cost, time and environmental pollution. The study has been focused on the impact assessment of the various architectural scenarios of energy efficiency upgrading on the Life Cycle Energy Consumption (LCEC) and Life Cycle CO2 (LCCO2) emission. Within the scope of the study, a primary school building is selected to be analysed. Through analysis, the total embodied and operational energy use and CO2 emission regarding the life cycle phase of the building is quantitatively defined and investigated in the framework of life cycle inventory. The paper concentrates on the operation and embodied energy consumption arising from the application of a variety of measures on the building envelope. An educational building with low LCCO2 emissions and LCEC in Turkey is proposed. To exemplify the approach, contributions are applied to a case study in Istanbul as a representative school building. The primary energy consumption of the case study building is calculated with a dynamic simulation tool, EnergyPlus. Afterwards, a sort of architectural energy efficient measures is implemented in the envelope while the lighting and mechanical systems remain constant. The energy used in the production and transportation of materials, which are the significant parts of the embodied energy, are taken into account as well.
Development of an integrated low-carbon heating system for outdoor swimming pools for winter application
Authors: Li Yantong , Huang Gongsheng
Published: August 2019

This paper presents an integrated low-carbon heating system for outdoor swimming pools, which aims to make outdoor swimming pools in subtropical climates available in winter season with economic feasibility. The heating system consists of solar heat collectors, air-source heat pumps, and PCM storage tanks. The solar heat collectors collect heat from solar radiation; while the air-source heat pumps collect heat from ambient air. The PCM storage tanks are used to store the heat collected by the air-source heat pumps during off-peak hours and supply heat during the open hours of outdoor swimming pools when the solar heat is insufficient. We investigated the collaboration of the two heating sources at the design stage regarding energy and economic performance using numerical simulation. Three cases with different percentage of heat contribution from these two sources were studied and compared using the indices of initial investment, operational cost, energy use and thermal comfort unmet percentage. Results were analysed to show how the percentages of the heat contribution from the two sources affect the energy and economic performance of the proposed heating system.
Techno-economic and environmental performances of heating systems for single-family code-compliant and passive houses
Authors: Dodoo Ambrose
Published: August 2019

In this study the implications of different energy efficiency requirements and heating solutions for versions of a single-family house in southern Sweden is explored. Final energy use, primary energy use, climate impacts and lifecycle cost of heat supply are analyzed for the building versions designed to meet the current Swedish BBR 2015 building code and heated with district heating or exhaust air heat pump. A case where the building is designed to the Swedish passive house criteria and heated with exhaust air heat pump is also analyzed. The district heating is assumed to be supplied from combined heat and power plants using bio-based fuels. For the heat pump solutions, cases are analyzed where the electricity supply is from coal-fired condensing power plant or fossil gas combined cycle power plant as baseline scenario, and from a combination of improved fossil power plants and non-fossil power plants as long-term scenario. The analysis considers the entire energy chain from natural resources to the final energy services. The results show that the BBR heat pump heated building use the most primary energy compared to the other two alternatives. Lifecycle cost is reduced by about 7-12% when district heating is used instead of heat pump for a BBR code-compliant building. This study shows the importance of lifecycle and system-wide perspectives in analyzing the resource efficiency and climate impacts as well as economic viabilities of heating solutions for houses.
Experimental investigation of the wind direction influence on the cooling of photovoltaic panels integrated in double skin façades
Authors: Hudișteanu Sebastian Valeriu , Popovici Cătalin George
Published: August 2019

The paper presents a wind tunnel experimental investigation of a small-scale building model (1:30). The main objective of the study is to determine the influence of the reference wind direction over the ventilation inside the double skin façade (DSF) channel. The analyzed system consists of a building equipped with photovoltaic panels as the exterior glazing of DSF. The tests were achieved by conceiving and implementation of an experimental program using a wind tunnel with atmospheric boundary layer. The aim is to determine with acceptable probability the velocities that can be reached in the ventilated façade channel during the warm season and to establish a correlation between the external reference velocity magnitude and direction and the velocity field generated inside the channel of the façade. Measurements were carried out for the reference wind speed, total, dynamic and static pressure both in the reference point and inside the façade channel. The results of the investigation highlighted the correlation between the velocity and direction of the reference wind and the dynamics of the air movement inside the double skin façade. The measurements showed that for the analyzed configuration of the double skin façade, there is an optimal wind direction that ensures the best cooling effect to photovoltaic panels. Also, the convective heat transfer coefficients were determined under these conditions. The decrease of the photovoltaic panel’s temperature determines a raise of its efficiency and generated power.
An industry perspective on building simulations with solar shading
Authors: Foldbjerg Rasmussen Helle , Skov Pedersen Tobias
Published: August 2019

This case study illustrates the difficulties that designers encounter when trying to simulate building performance taking both daylight, indoor climate and view out into account. An example of a workflow for combined climate-based daylight and indoor climate calculations using two separate software is shown for illustrating the challenges. Furthermore, the study shows how the evaluation of indoor climate, daylight and view out, in accordance with EN 15251, EN 17037 and EN 14501, can be linked together as a basis for comparison of different solar shading technologies for ZEB buildings.
Retrofit solutions for an historic building integrated with geothermal heat pumps
Authors: Carnieletto Laura , Emmi Giuseppe , Artuzzi Marco , Piazza Maria Celeste , Zarrella Angelo , De Carli Michele
Published: August 2019

Since the beginning of this century, according to EPBD Directive, Italian legislation has been focusing on existing buildings’ retrofit, as they represent a large part of the national building stock. In this context, the most difficult challenge is preserving heritage and obtaining energy saving at the same time, which is the aim of the European Standard EN 16883 published in 2017. Currently there are few energy efficiency actions that can be applied to improve the energy performance of these buildings, due to the strict regulation on ‘protected status’.

The case study presented in this paper gives an overview of refurbishment solutions that can get around Italian legislation for one of the oldest heritage buildings in Padova. The building complex that can be seen nowadays is the result of the grouping of several surrounding buildings, renaissance palaces and medieval towers. Energy simulations have been implemented using EnergyPlus software. The thermal behaviour of the building has been investigated considering the peculiarities of the envelope and real weather data. Internal loads and generation system schedules have been estimated based on the information obtained from the system monitoring the energy consumption. Envelope and system retrofit have been considered.
A Cradle-to-Grave Carbon Index (CI) for Design, Construction and Operations of Site-Specific Buildings
Authors: Setty Boggarm , Woods James
Published: August 2019

During the 1970s, the Energy Utilization Index (EUI) was introduced in terms of the annual rate of energy used per unit of floor area in site-specific buildings. It indicates energy but not total resource use effectiveness of design alternatives compared to baseline values (i.e., targets). Because of increasing concerns about indoor and outdoor emissions from carbon-based products and processes, an analogous “Carbon Index” (CI) is here introduced as a cradle-tograve design tool for evaluating the performance of design alternatives in terms of carbon emitted throughout the five stages of a building’s lifespan: siting, design, construction, operations, and demolition/recycling. This CI is expressed as equivalent mass of CO2 per unit floor area (CO2e). At each stage, this CI is determined as the sum-of-products of two factors: 1) “Primary Factors” (PF), scalars that are defined and quantified by the designer; and 2) “Carbon Impact Factors” (CIF), which are standardized 2x1 matrices that characterize the PFs in terms of “embodied” CO2e emissions in the materials, assemblies, and equipment that are installed in the building, and as CO2e emissions that are released during the “operations” of the building. This design tool is posited to foster more accurate calculations of carbon emissions for design alternatives.
Energy Modeling with Nonlinear-Autoregressive Exogenous Neural Network
Authors: Syed Asad Hussain , Richard Kwok Kit Yuen , Eric Wai Ming Lee
Published: August 2019

The model-based predictive control (MPC) is considered to be an effective tool for optimal control of building heating, ventilation, and air-conditioning (HVAC) systems. MPC need to update the operating set points of the local control loops that have a significant influence on the energy performance of the system. Performance of MPC relies on the accuracy of the system performance model. There are two commonly used modeling approach – conventional or analytical approach that is the way of process modeling for some time, but it tends to increase the online computational load as it requires a full mathematical description of the real system. Furthermore, such techniques rely on different simplifying assumptions that limit the accuracy of the performance model. A second commonly used technique is the data-driven approach. The neural network (NN) is the most potent data-driven approach. NN can accurately model complex nonlinear systems without even knowing the structure of the system and it also addresses the problem of the online computational load since the computational load moves to the offline training step.

In order to set up neural network model-based predictive control (NNMPC), it is important to build a reliable energy model of HVAC system that can be used to perform multi-step-ahead prediction of system energy performance. In this paper, the energy modeling of the chiller plant is conducted. Data for the training of chiller plant energy model is generated from HVAC testbed build in TRNSYS simulation environment. The nonlinear-autoregressive neural network with exogenous input (NARX) is used to model the energy performance of the chiller plant. The NARX is a powerful method for forecasting of time series data and dynamic control problems. NARX model is first trained in the open-loop form with the actual output instead of feedback, using back-propagation with the Levenberg-Marquardt method; this model can be used to perform only one-step-ahead prediction. Open-loop NARX model is transformed into a closed-loop form, by connecting the internal feedback, i.e. actual output is replaced by predicted output, to perform multi-step-ahead prediction (for predictive control).

Comparative analysis of developed NARX-based chiller model is carried out with respect to process data from testbed, which demonstrated the good accuracy of the NARX-based chiller model.
Vulnerabilities and resilience in Danish housing stock: A comparative study of architectural answers to climate change in Danish housing in relation to other oceanic climates
Authors: Poulsen Rydborg Mikkel , Lauring Michael , Brunsgaard Camilla
Published: August 2019

Climate change will affect the same climate zones relatively similarly. When considering how to design residential architecture for future climates it is therefore relevant to understand how residential architecture can adapt within the specific climate zone.

Denmark is placed within the oceanic climate zone and shares many of the same problems that countries in similar climates do. However, the architectural responses have developed radically different. Denmark has been building heating efficient housing for the last decade, which have lately caused increased overheating problems and surging energy demands for cooling.

This paper compares the architecture of different oceanic zones with Danish architecture. The strategies for adapting to climate change represents a broad variety.

Western European tradition has itself created varied methods for coping with the climatic struggles their societies meet. Danish architecture has for centuries been focused on heavy robust constructions that would withstand the large amount of precipitation and wind that is predominant in the country. In Holland flood danger has been a constant threat to society, which has led both to defensive and reactive measures in the form of dykes and amphibious housing. On the other side of the globe, New Zealand’s traditional architecture has adapted to similar problems but with a much lighter construction, leading to architecture that is resilient to lateral forces like wind and earthquakes. While lacking the thermal properties of northern European houses the New Zealand homes show a remarkable flexibility and mobility through simple timber-frame constructions.

The vulnerabilities in the Danish building stock is due to an unwillingness to invest in adaptive measures. It might be necessary to integrate a flexible building style to future sustainable housing and build up a different expectation for how a house is used. In the face of climate change, architecture need to be adapted to the problems apparent on the building site and draw on experiences from other cultures that might have faced similar problems in the past. Danish architects might likewise use the non-rocky ground for water retention through planting and landscaping strategies in relation to architecture.
Impact of space layout on energy performance of office buildings coupling daylight with thermal simulation
Authors: Du Tiantian , Jansen Sabine , Turrin Michela , van den Dobbelsteen Andy
Published: August 2019

Space layout design is one of the most important phases in architectural design, and current studies have shown that it can affect building energy performance. However, its influence has not been quantified. This paper aims at investigating the impact of space layouts on building energy performance. We use the floor plan of an office building in the Netherlands as reference, and propose eleven space layouts based on the reference. Calculations are performed with the tools Honeybee and Ladybug in Grasshopper, which are developed based on Daysim and EnergyPlus, to simulate lighting, cooling and heating demand of these layouts. In addition, we couple daylight with thermal simulation, by importing the artificial lighting schedule calculated in Daysim to EnergyPlus. The result shows that the heating demand of the worst layout is 12% higher than the best layout, the cooling demand of the worst layout is 10% higher than the best layout, and the lighting demand of the worst layout is 65% higher than the best layout. The total final energy use of the worst layout is 19% higher than the best layout.
Climate change impact on energy balance of net-zero energy buildings in typical climate regions of China
Authors: Chai Jiale , Huang Pei , Sun Yongjun
Published: August 2019

Net-zero energy building (NZEB) is widely considered as a promising solution to the current energy and environmental problems. The existing NZEBs are designed using the historical weather data (e.g. typical meteorological year-TMY). Nevertheless, due to climate change, the actual weather data during a NZEB’s lifecycle may differ considerably from the historical weather data. Consequently, the designed NZEBs using the historical weather data may not achieve the desired performance in their lifecycles. Therefore, this study investigates the climate change impacts on NZEB’s energy balance in different climate regions, and also evaluates different measures’ effectiveness in mitigating the associated impacts of climate change. In the study, the multi-year future weather data in different climate regions are firstly generated using the morphing method. Then, using the generated future weather data, the energy balance of the NZEBs, designed using the TMY data, are assessed. Next, to mitigate the climate change impacts, different measures are adopted and their effectiveness is evaluated. The study results can improve the understanding of climate change impacts on NZEB’s energy balance in different climate regions. They can also help select proper measures to mitigate the climate change impacts in the associated climate regions.
Experimental study of radiator, underfloor, ceiling and air heater systems heat emission performance in TUT nZEB test facility
Authors: Võsa Karl-Villem , Ferrantelli Andrea , Kurnitski Jarek
Published: August 2019

This paper reports the results of different heat emitter system measurements, which were carried out at the nZEB test facility near Tallinn University of Technology in early 2018. Radiators, underfloor heating, air heaters and radiant ceiling panels are studied as coupled with different control schemes ranging from ON-OFF to PI-type control. The objective is to assess and quantify the control accuracy and thermal comfort parameters among different configurations.

Scheduled heating dummies are used to simulate internal heat gains within the otherwise unoccupied test rooms. Along with outdoor temperature variation, the heating demand is therefore constantly changing and the control systems are continuously adjusting the heat output to maintain the desired indoor air temperatures. Control accuracy is then determined from the temperature deviations against this set value. Air stratification within the room is assessed with vertical temperature gradient calculations from measured air temperatures at different heights. The operative temperature at the point of expected occupancy is calculated from surrounding air and enclosing surface temperatures.

The quantified results provide a comprehensive comparison between the different system configurations, enabling further energy simulations in related software packages since these parameters directly influence the energy usage within a system.
House owners’ experience and satisfaction with Danish low-energy houses - focus on ventilation
Authors: Knudsen Henrik N.
Published: August 2019

The purpose of this study was to evaluate house owners’ experience and satisfaction with the first Danish detached low-energy single-family houses, built according to energy class 2015 before these supplementary requirements became standard for all new dwellings. A questionnaire survey was carried out among owners of newly built energy class 2015 houses. The paper presents the house owners answers to questions on their overall satisfaction, their heat consumption, and their satisfaction with the indoor environment (temperature, draught, air quality, noise and daylight). There is a focus on issues related to having a mechanical ventilation system, i.e. satisfaction with the air quality, does the air feel dry in winter, and does the ventilation system make noise and how the airing behaviour is in winter. As many as 370 out of 869 house owners, corresponding to a response rate of 43%, answered the questionnaire. There was an overall satisfaction with the new low-energy houses. More than 90% of the house owners perceived the indoor environment as satisfactory. The energy consumption was as low as expected by 59%, while only 7% answered that it was higher than expected. Compared with previous similar studies, problems with technical installations have decreased. However, there is a need for continued focus on the commissioning of new and not necessarily thoroughly tested, high-performance installations and new designs. Based on the survey a series of recommendations are given that might help to achieve both a low energy consumption and satisfied occupants of new low-energy dwellings.
Design and integration of heat pumps for nZEB in IEA HPT Annex 49
Authors: Wemhoener Carsten , Buesser Simon , Rominger Lukas
Published: August 2019

Heat pumps are a promising building technology, especially for nearly Zero Energy Buildings (nZEB) to be introduced in the EU by the beginning of 2021 for all new buildings. Despite heat pumps already range among the most efficient heat generators, further efficiency and cost optimisation is seen in system integration as well as in adapted design and control for the application in nZEB. IEA HPT Annex 49 investigates heat pump application in nZEB by simulation and field monitoring in order to evaluate integration options with other building technologies, thermal and electrical storages, the building envelope and the ground. Moreover, design and control for the loads in nZEB and the integration of nZEB into connected energy grids are considered. The investigations are accompanied by field monitoring of heat pumps in different nZEB applications and climate conditions in order to relate calculation results to the real operation and identify optimisation potentials. Expected results of the Annex 49 are recommendations regarding heat pump integration options and related design and control as well as real world heat pump performance in monitored nZEB. The paper gives an overview on the Annex 49 project and national contributions and will present first interim results of the Annex Tasks.
Identifying typical hourly DHW energy use profiles in a hotel in Norway by using statistical methods
Authors: Ivanko Dmytro , Nord Natasa , Sørensen Åse Lekang , Plesser Thale Sofie Wester , Walnum Harald Taxt , Sartori Igor
Published: August 2019

The aim of this research is to improve the existing approaches of domestic hot water (DHW) energy use analysis in buildings. A comprehensive statistical analysis of hourly DHW energy use for a hotel in Oslo, Norway, was performed. To recognize the trend of DHW energy use over several years, Centered Moving Average method was applied. To increase the accuracy of DHW energy use analysis, it was proposed to identify the months and days of the week with similar characteristics of DHW energy use and build unified profiles for them. For this purpose, the approaches based on the student’s t-tests and Fisher’s test was proposed. The analysis allowed us to detect two seasons of DHW energy use. In addition, it was revealed that behavior of DHW energy use on Mondays significantly different from other working days. To recognize the timing of peak and average and low DHW energy use, method of statistical grouping of the hourly energy use was utilized. The typical profiles of DHW energy in the hotel were obtained. The profiles proposed in the present article more reliably reflect the regimes of DHW energy use in the hotel and take into account factors that have influence on DHW use.
Properties of the Triangular Excitation Pulse and the 3D Heat Transfer Effects in the Excitation Pulse Method
Authors: Rasooli Arash , Itard Laure
Published: August 2019

Concerning the high levels of energy consumption in the existing building stock, the necessity for characterization of the building envelop is a well-known issue. Accordingly, numerous methods and practices have been developed and studied to measure the thermal resistance and other thermal characteristics of the walls in-situ. In the current paper, a previously proposed method, the Excitation Pulse Method, EPM, based on the theory of thermal response factors, is further studied and investigated through simulations, to rapidly measure the thermal resistance of existing walls. A prototype is built and introduced to carry out larger number of measurements on site. The triangular pulse’s properties such as the relation between its magnitude and its time interval on its corresponding response are investigated. It is shown how changes in time interval can make the method sensitive to the number of residuals and affect its reliability. General constraints and validity domain of the method are studied. In addition, the effect of 3D heat transfer on the performance of the method is further illustrated in light and heavy constructions. It is shown in which cases it is possible to apply the method in-situ and measure the thermal resistance within a couple of hours.
Minimization procedure of experimental tests for calibration purposes, within HVAC&R energy efficiency framework
Authors: Morales-Ruiz S. , Oliet C. , Castro J. , Rigola J. , Oliva A.
Published: August 2019

Simulation models and predictive tools need to be fast, accurate and robust at the same time. The models that have to provide numerical solutions under transient conditions for a long period of time need to be simple with the aim of minimizing the time respond, without losing the accuracy. Thus, previous experimental data and a calibration methodology are necessary to assure this objective, both are strictly necessary to reproduce the behaviour with accuracy expected. Consequently, even accurate information (e.g. look-up tables) for HVAC&R components (e.g. heat exchangers, fan/compressor, auxiliary elements, etc.) is known and all coupling system is developed, the minimization of experimental tests for calibration purposed based scattered data interpolation is now an important aspect, which looks for reducing the quantity of experiments necessary to assure the accuracy expected from an optimization point of view. The present work shows an optimization procedure based on test number minimization according detailed error comparison against existing previous data. Illustrative results for a specific component are presented highlighting test number reduction without losing accuracy.
Evaluation of in-depth energy modelling for the design and operation of a net-positive energy Solar Decathlon house
Authors: Banfield Brendan , McDowell Clayton , Robinson Duane A. , Agalgaonkar Ashish
Published: August 2019

The Solar Decathlon is an international competition that challenges collegiate teams from around the world to design and build functioning, sustainable, solar powered houses. The competition is split into ten sub-contests which vary from competition to competition. Contests are a combination of juried (judged by a panel experts) or measured (such as energy usage and thermal comfort) contests. This paper will focus on the measured contests, in particular; energy management, comfort conditions and house functioning. To ensure optimal house performance during the competition, extensive energy and thermal modelling is required to ensure the solar PV and on-site energy storage can achieve net-zero energy while also ensuring the heating, ventilation and air conditioning (HVAC) system can meet the strict indoor thermal comfort requirements set by the competition. This paper will review the energy and thermal modelling process of Team UOW Australia’s net-positive energy house, the ‘Desert Rose’, that achieved second place in the Solar Decathlon Middle East (SDME) competition in 2018. Upon reviewing the energy modelling process, the results from the energy simulations will be compared to the real data that was obtained during the SDME competition to determine the validity of the energy simulations and the subsequent benefits of in-depth energy modelling for competing in a Solar Decathlon.
Metamodeling of building energy consumption focused on climate, operation, space use and users related factors
Authors: Novel Aymeric , Allard Francis , Joubert Patrice
Published: August 2019

Energy performance guarantee projects aim at achieving a given energy consumption in real life conditions. Building energy consumption monitoring during operation phase often reveals that energy consumption is sensitive to building spaces use and systems operation quality, especially for buildings with high energy performance characteristics [7]. Other investigations show the impact of building users’ behaviour on energy consumption [28]. These factors must be added to climate factors for energy consumption prediction during operation phase. Number of factors and possible combinations is very high. Building energy modeling is limited regarding this issue and metamodeling has been used to solve this problem [25]. We developed metamodels that are polynomial functions using D-optimal design of experiment (DOE) approach. Such metamodels can become operational tools to use in the IPMVP framework, associated with a M&V plan. This paper shows the application of the method on a cultural building that comprises numerous systems and usages. We obtain a reliable metamodel of the energy consumption as a function of climate, operation, and space use factors. which meets IPMVP [11] and ASHRAE Guideline 14 [3] modeling uncertainties criteria. We also determine the global uncertainty resulting from predictors’ uncertainties propagation and modelling uncertainty associated with the metamodel.
Energy Efficient Control of the Dehumidification Process in Heat Exchangers with Air Bypass
Authors: Kusche Stephan , Badura André
Published: August 2019

This paper deals with an energy efficient approach for the dehumidification process of supply air. The basic concept consists of an air bypass, which separates the airstream. Later the unprocessed air is mixed with the conditioned air. This mixing allows one to avoid the energy consuming reheating of the air stream. Application of this concept demands for a sophisticated controller. In this case a state space controller is designed. Therefore, the underlying model for the heat exchanger is derived and a Krylov Space based reduction method is applied. This model is broadened for the bypass. The overall linear model is derived via numerical linearization.
Optimizing production efficiencies of hot water units using building energy simulations - Trade-off between Legionella pneumophila contamination risk and energy efficiency
Authors: Van Kenhove Elisa , De Backer Lien , Laverge Jelle
Published: August 2019

The energy needed for domestic hot water represents an important share in the total energy use of well-insulated and airtight buildings. One of the main reasons for this high energy demand is that hot water is produced at temperatures above 60°C to mitigate the risk of contaminating the hot water system with Legionella pneumophila. However, this elevated temperature is not necessary for most domestic hot water applications, and has a negative effect on the efficiency of hot water production units. A simulation model has been developed which proposes an alternative to this constant 60°C by predicting the Legionella pneumophila concentration dynamically throughout the hot water system. Based on this knowledge, a hot water controller is added to the simulation model that sets a lower hot water comfort temperature in combination with heat shocks. In this paper, the simulation model is used to estimate the energy saving potential in a case study building, at the level of the heat production system by reaching higher production efficiencies. Three different production units, namely an electric boiler, heat pump and solar collector have been investigated. The controller is expected to become an alternative for the current, energy intensive, high temperature tap water heating systems.
Proposal and Evaluation of an Equipment Operating Method Using Solar Radiation Prediction in a Zero Energy House
Authors: Oki Reina , Tsuneoka Yugo , Yamaguchi Shingo , Sugano Soma , Nakagawa Jun , Watanabe Naoya , Kobayashi Tatsuhiro , Tanabe Shin-ichi , Akimoto Takashi , Hayashi Yasuhiro , Wakao Shinji
Published: August 2019

Because of the increasing promotion of renewable energy such as photovoltaic (PV) panels in Japanese houses, the voltage increase and frequency adjustment of a city electrical distribution network sys-tem will be of concern. Therefore, self-consuming surplus electricity and leveling the reverse power flow is important in terms of reducing the smart grid network load and reducing the peak load of the smart grid network. The aim of this study was to acquire knowledge regarding methods of self-consuming surplus power as well as leveling the reverse power flow. An equipment operation method, termed “schedule control,” was proposed that changes the operational time of a heat pump water heater and the charging time of a storage battery according to solar radiation prediction. Because PV power fluctuates depending on weather and time zone, this method helps in self-consuming as much PV power generation as possible. By actual measurement and simulation results, it was confirmed that the schedule control of the heat pump water heater and storage battery was useful in self-consuming surplus power and leveling reverse power flow.
Towards Next Generation Building Management Systems
Authors: Noran Ovidiu , Sota Ion , Bernus Peter
Published: August 2019

The Internet of Things (IoT) paradigm is gradually finding its way in virtually every industry; however, beyond adding more sensors and measuring and controlling previously inaccessible domains, it is also about transforming ‘legacy’ approaches to control systems, such as those used in Building Management Systems (BMS), by leveraging on the advantages brought by Cyber Physical Systems (CPS). The purpose of this paper is to address several issues gradually emerging in the process of applying the CPS and IoT paradigms to revolutionise BMS. The results of this on-going research aim to help avoid potential pitfalls and provide a sound platform for taking advantage of the benefits brought by this technology in a feasible, effective and controlled manner. More specifically, the paper will address i) the changing meaning of interoperability in the context of the explosion in the number of IoT devices, ii) the need for guidance in adopting sustainable CPS and IoT platforms supporting BMS, based on appropriate non-functional and viable systems principles, iii) emerging issues in the BMS ‘cloudification’ endeavour and iv) the lack of data sources’ correlation resulting in sub-optimal data quality and detail in using Big Data technologies to enable effective analytics for prompt BMS decision-making.
Validity of CO2 based ventilation design
Authors: Melikov Arsen K. , Markov Detelin G.
Published: August 2019

The present ventilation design practice as well as the ventilation standards and building regulations are based on the assumption for complete mixing of air in occupied spaces. Required flow rate of outdoor air for dilution of metabolic CO2 generated by occupants is calculated to keep the CO2 concentration below certain required level. The CO2 concentration measured in the exhaust air or in the room but far from the occupants is assumed to be the same as the CO2 concentration in the air inhaled by the occupants. However, this assumption is seldom accurate, especially in spaces with closely seated occupants, such as classrooms, meeting rooms, etc. In such spaces the CO2 sources, i.e. the people, are close to each other and the CO2 concentration in the inhaled air may be much above the CO2 concentration level recommended as a limit in standards. This is because the upward free convection flow that exists around human body entrains the air with high CO2 concentration exhaled by seated people and move it to their breathing zone. Furthermore, the thermal flows generated by occupants’ body interact with the ventilation flow, which often results in insufficient dilution of the generated CO2 (as well as other pollution) and high levels of CO2 concentration at the breathing zone of occupants. This problem is discussed in the present paper in detail. The discussion is supported by results of measurements in a meeting room with mixing air distribution. People were used to generate metabolic CO2 and a breathing thermal manikin was used to measure accurately the CO2 concentration in the inhaled air. The results confirmed that inhaled CO2 concentration was much higher than the one at the exhaust and that there is need for changes in the present CO2 based ventilation design practice. Possible solutions are suggested.
ANN Based Optimized AHU Discharge Air Temperature Control of Conventional VAV System for Minimized Cooling Energy in an Office Building
Authors: Lee Jong Man , Kang Won Hee , Lee Kwang Ho
Published: August 2019

In most conventional forced-air systems, the guidelines for the air handling unit(AHU) discharge air temperature(DAT) are not fully established and thus AHU DAT are constantly fixed to a particular set-point, regardless of dynamic changes of operating variables. In this circumstance, this study aimed at developing a control algorithm that can operate a conventional VAV system with optimal set-points for the AHU DAT. Three-story office building was modeled using co-simulation technique between EnergyPlus and Matlab via BCVTB(Building Controls Virtual Test Bed). In addition, artificial neural network(ANN) model, which was designed to predict the cooling energy consumption for the upcoming next time-step, was embedded into the control algorithm using neural network toolbox within Matlab. By comparing the predicted energy for the different set-points of the AHU DAT, the control algorithm can determine the most energy-effective AHU DAT set-point to minimize the cooling energy. The results showed that the prediction accuracy between simulated and predicted outcomes turned out to have a low coefficient of variation root mean square error (CvRMSE) value of approximately 24%. In addition, the predictive control algorithm was able to significantly reduce cooling energy consumption by approximately 10%, compared to a conventional control strategy of fixing AHU DAT to 14°C.
Energy performance optimization of buildings using data mining techniques
Authors: Corten Kai , Willems Eric , Walker Shalika , Zeiler Wim
Published: August 2019

The operational energy consumption of buildings often does not match with the predicted results from the design. One of the most dominant causes for these so-called energy performance gaps is the poor operational practice of the heating, ventilation and air conditioning (HVAC) systems. To improve underperforming HVAC systems, analysis of operational data collected by the building management system (BMS) can provide valuable information. In order to completely use and interpret operational data, the building sector is urging for methods and tools. Data mining (DM) is identified as an emerging powerful technique with great potential for discovering hidden knowledge in large data sets. In this study, the performance of HVAC systems was analysed using regression analysis as DM technique. This leads to valuable insights to control and improve the building energy performance. The results show that a reduction of 7-13% on the heating demand and 41-70% on the cooling demand can be obtained.
Hit2Gap Project: Highly Innovative building control Tools Tackling the energy performance gap
Authors: Costa Andrea , Pietrobon Marco , Messervey Thomas
Published: August 2019

Measurement campaigns have shown major discrepancies in buildings energy performance between planned energy demand and real energy consumption, while nowadays most of the newly constructed offices buildings are equipped with BMS systems, integrating a more or less extended measurement layer providing large amounts of data. The HIT2GAP project has developed a new generation of building monitoring and control tools based on advanced data treatment techniques allowing new approaches to assess building energy performance data, getting a better understanding of building’s behaviour and hence a better performance. From a strong research layer on data, HIT2GAP solution builds on existing measurement and control tools that are embedded into a new software platform for performance optimization. The HIT2GAP solution is applied as a novel intelligent layer offering new capability of the existing BMS systems and offering the management stakeholders opportunities for services with a novel added value. Applying the solutions to groups of buildings also allows to test energy demand vs. local production management modules. This solution is being tested in various pilot sites across Europe. HIT2GAP work has been carried out with a permanent concern about market exploitation of the solutions developed within the project. This paper will present the project solution in detail and showcase the achievement so far in the real case demo sites.
The “HumFlow” Project – Developing a minimal invasive measurement system for estimating energy and humidity transfer processes through building walls
Authors: Cavaterra Alessio , Böttcher Andreas , Lambeck Steven
Published: August 2019

Establishing suitable indoor climate conditions for exhibits in historical buildings is one of the main goals for curators in museums and exhibitions. Different guidelines in the field of preventive conservation provide therefore useful criteria and methods to prevent or to delay the deterioration of the objects of cultural heritage. Maintaining such a suitable indoor climate often needs the usage of expensive HVAC-equipment, whose installation occasionally damages the historical structure of such buildings and poses a problem for protection standards for historical monuments. The ongoing “HumFlow” project contributes to the solution of two problems: Firstly, avoiding damages to building structures provoked by installation of measurement devices and, secondly, gaining enough measurement data and information of humidity and energy transfer processes of walls and other surfaces by developing a minimal invasive measurement system. This paper focuses on the overall project goals, describes the test bed including experiment design, discusses the first results and provides a simple hygrothermal model of a flat wall. Therefore, it can be seen as an introduction for subsequent contributions of this project.