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Demand-controlled ventilation (DCV) is a crucial part of ventilation design used in buildings and its effects are widely studied in modern construction. To assess the effect of DCV, accurate models...

Buildings globally are subjected to climate change and heatwaves, causing a risk of overheating and increasing energy use for cooling. Low- energy cooling solutions such as night cooling are promising to realize energy reduction and climate goals. Apart from energy performances, resilience is gaining importance in assessing the performance of the building and its systems. Resilience is defined as “an ability to withstand disruptions caused by extreme weather events, man-made disasters, power failure, change in use and atypical conditions; and to maintain capacity to adapt, learn and transform.” However, there is a clear lack of Resilience indicators specific for low energy cooling technologies. In this paper, the resilience of the night cooling in a residential building in Belgium is assessed for two external events: heat wave and shading failure. This paper shows the first attempt of a resilience indicator for night cooling as the effect on the shock of solar shading failure, heat wave or combination of both. It takes 3.4 days to bring down the temperature below 25℃, in case of shading failure and heatwaves compared to 9 hours in the reference case. Further research is needed to determine resilience indicators as a performance criteria of low-energy cooling systems. ispartof: iCRBE Procedia vol:1 issue:1 ispartof: 1st International Conference on Climate Resilient Built Environment iCRBE, 21 location:Bali, Indonesia date:21 Sep - 23 Sep 2020 status: Published online

Copyright © 2021 The Author(s). The global effects of climate change will increase the frequency and intensity of extreme events such as heatwaves and power outages, which have consequences for buildings and their cooling systems. Buildings and their cooling systems should be designed and operated to be resilient under such events to protect occupants from potentially dangerous indoor thermal conditions. This study performed a critical review on the state-of-the-art of cooling strategies, with special attention to their performance under heatwaves and power outages. We proposed a definition of resilient cooling and described four criteria for resilience—absorptive capacity, adaptive capacity, restorative capacity, and recovery speed —and used them to qualitatively evaluate the resilience of each strategy. The literature review and qualitative analyses show that to attain resilient cooling, the four resilience criteria should be considered in the design phase of a building or during the planning of retrofits. The building and relevant cooling system characteristics should be considered simultaneously to withstand extreme events. A combination of strategies with different resilience capacities, such as a passive envelope strategy coupled with a low-energy space-cooling solution, may be needed to obtain resilient cooling. Finally, a further direction for a quantitative assessment approach has been pointed out. The research is supported by Det Energiteknologisk Udviklings- og Demonstrationsprogram (EUDP) under grant 64018-0578. It was also supported by the Assistant Secretary for Energy Efficiency and Renewable Energy, Building Technologies Office of the U.S. Department of Energy under Contract No. DE-AC02-05CH11231.

The building sector has to significantly reduce the total energy use. A predictive control could be a solution to control an HVAC system more energy efficiently since it takes into account the current measurements and the future demand. In this study a predictive control framework is implemented in an educational building with two lecture rooms. The airflow rate is controlled by VAV boxes based on measurements of CO2 concentration and operative temperature. The dynamic model used for optimization of the control input is a grey-box model, previously identified using measurement data. Weather forecasts and weekly lecture schedules are used as forecasts for the optimization of future control actions. The control actions resulting from the optimization are written to the set points for supply air temperature and VAV damper position using the BACnet interface. Results of the first trial indicate that the predictive control is able to control the room temperature and CO2 concentration, even with uncertainty introduced by the forecasts. Prediction errors observed were 0.17 ˚C for room temperature and 87 ppm for indoor CO2 concentration.

Rule-based control (RBC) strategies are often unable to execute the optimal control action, which leads to unnecessary energy consumption and suboptimal comfort. Model predictive control (MPC) is a dynamic control strategy for heating, ventilation and air-conditioning (HVAC) systems that is mostly more capable of performing optimal control actions. The identification process of predictive models is an essential aspect of MPC. However, this model identification process remains time consuming due to the large variation in buildings and systems. The aim of this paper is to determine guidelines to identify predictive grey-box models more time efficient, thus enhancing the applicability of MPC. This paper focusses on a case study building equipped with an all-air HVAC system, which combines ventilation, heating and cooling. Making both temperature and CO2-concentration key parameters to predict. The grey-box model represents an open zone in a landscaped office, making the influence of neighbouring zones an additional challenge. Different models for predicting the zone temperature and CO2-concentration are identified, evaluated and validated using CTSM-R. The following aspects are studied: the dataset size, the influence of neighbouring zones, the difference between winter and summer conditions, number of states and the prediction horizon. A three state RC-model with the implementation of the zone temperature of one neighbouring zone is preferred for predicting the indoor temperature with an acceptable prediction horizon of one day. However, this temperature model is not suitable during sunny periods. A simple model representing a mass balance obtains accurate predictions of the zone CO2-concentration for a timestep of 15 minutes. For both model types the utilization of 5-day datasets is favoured over 12-day datasets due to a shorter monitoring period, lower prediction error and an easier parameter convergence. The usage of 12-day datasets is only preferred when an accurate estimation of the thermal inertia is pursued.

The CO2 emissions and energy use of SMEs in the tertiary sector (e.g. small food and non-food shops, restaurants, offices, pubs, etc.) are high and there are few initiatives to reduce because this target group is difficult to reach due to small scale and diversity. The Flemish-Dutch TERTS project wants (1) to make the sector aware of the potential of and (2) to demonstrate energy transition and energy efficiency of innovative technologies. This paper is focussing on butcher’s shops. A reference model is made based on data of 90 existing shops in Flanders (Belgium). The energy use of the building and systems is calculated according to DIN V 15 899. The cost-benefit of various measures is calculated and compared. Results show that the main energy consumers of a butcher shop are cooling, lighting and domestic hot water, whereas heating only has a rather small contribution. There are several cooling needs: product-cooling (in walk-in freezers, walk-in coolers and the cooling counter) and cooling of the workshop. The combination of the following measures is concluded to be the most favourable and leads to a reduction in final energy consumption of 60 %: a reflective coating on the flat roof and extra roof insulation, relighting with LED, air-to-water heat pump for the generation of domestic hot water and PV panels as local energy generation.

The optimal control of the HVAC system in the nearly zero energy buildings (nZEBs) can be considered as a challenge. Indeed, the lack of data given by monitored data does not allow understanding what are the implications of different strategies on thermal comfort and energy consumptions. This paper determines an approach for the evaluation of the management of the heating system in an existing educational nZEB. The aim is to understand how the energy efficiency of the heating system is sensitive to controls strategies and the important role played by the control systems. The test lecture rooms on KU Leuven Ghent Technology Campus (Belgium) have been chosen as case study. A deep analysis, starting from an in-field monitoring, was carried out during the winter period of 2019, in order to assess the actual operation and the energy use of building systems under real conditions. Then, a building energy simulation (BES) model of the building and its systems was developed and calibrated against the real monitoring data. Control strategies of the heating system are simulated and compared to the current configuration. The simulation results show that strategies based on a definition of a heating curve for the boiler can reduce the comfortable time (−23%). Controlling the temperature inside the storage tank as a function of the outdoor temperature together with the control on the activation of the air handling unit result in an energy savings from 32% to 46%, with a correspondent increase of comfort time in the period from 0.6% to 3.4% compared to the baseline scenario, depending to the relationship between the external temperature and water temperature inside the water storage tank.

Robust control systems are essential to guarantee an efficient usage of ventilative cooling. The most important challenges of controlling natural ventilative cooling are the outdoor environmental conditions like wind, rain, noise and pollen; security and interaction with and satisfaction of the user. The main control strategies and components of natural ventilative cooling, including actuators and sensors are described. From case studies, the following lessons are learned. The main driver for control of natural ventilative cooling systems is thermal comfort and outdoor weather conditions. Optimization and commissioning of ventilative cooling control is critical to maximize the cooling potential as well as to prevent overcooling. Conclusions on the interaction of the user with the ventilation cooling control are twofold. On the one hand, automatic control is preferred to manual control of ventilative cooling. On the other hand, the user should be able to overrule this automatic control. Suggestions for design are formulated. The users and their expectations of controllability play a central role. Moreover, the future maintenance of the actuators have to be taken into account in the design phase.

Throughout their lifetime, buildings might face unpredictable shocks leading to fast deterioration of comfort levels. The ability of buildings and systems to absorb the shock and bring back the indoor conditions to their designed state is termed as “resilience”. Ventilation and thermal resilience have been studied under homogeneous conditions. However, the established airflow indoors and hence resilience is non-homogeneous. In this work, the spatial aspect of ventilation and thermal resilience will be assessed in a classroom equipped with displacement ventilation using 3D CFD modeling. Two sources of pollution were considered in the space: CO2 and VOCs. To study resilience, the numerical model was simulated until steady state. Subsequently, a power outage shock of 60 min was induced. The temporal and spatial mappings of temperature, and pollutants’ concentration were recorded in the occupied zone at the breathing height of 1.2 m and compared to that at the exhaust. Building resilience was assessed through ppm.hours and degree.hours and compared at both locations. Results showed that resilience is rather a non-homogeneous field that depends on the location of heat sources and pollution sources in the space. However, results showed that any over or under estimations (~20 − 28%) in assessing the thermal or ventilation resilience are negligible when evaluated at either the breathing plane or the exhaust.

Demand controlled ventilation (DCV) refers to a ventilation system with air flow rates that are controlled based on a measurement of an indoor air quality (IAQ) and/or on a thermal comfort parameter. DCV operates at reduced air flow rates during a large amount of the operation time and thus consumes less energy for fan operation and heating/cooling the supply air. The aim of the present research is to assess the IAQ, ventilation efficiency, and the operation and energy efficiency of real operating DCV systems in moderate climates. Measurements are carried out for at least two weeks in autumn and winter 2015-2016. The following parameters were monitored: CO2 concentrations and air temperatures at different positions in the room and at the extract air grill, position of the variable air volume (VAV) boxes, supply and extract air flow rates and the occupancy of the room. Four case studies with large and varying occupancy rate and with different use and ventilation systems are selected. Two classrooms and three landscaped offices were evaluated. The results show that a DCV is interesting in rooms with a large and varying occupancy rate such as lecture rooms and landscaped offices. A good IAQ is measured in all cases studied even at reduced air flow rates. The effect of the reduced air flow on the ventilation efficiency is negligible. The VAV boxes react well to predefined set points for CO2 concentration. During the measurement period, the reduction for fan energy ranges from 25 to 55% and ventilation heat losses 25–32% compared to a constant air volume system (CAV) with a design airflow rate of 29 m3/(h.pers), i.e., IDA3 in EN 13779. However, commissioning of the DCV is necessary to obtain and maintain these performances. ispartof: pages:349-360 ispartof: Energy and Buildings vol:172 pages:349-360 ispartof: 8th AIVC - 6th TightVent & 4th venticool Conference location:Nottingham date:13 Sep - 14 Sep 2017 status: Published online

The study was performed in Ha Tinh city of Vietnam and aims to investigate the current thermal condition inside houses of different urban neighborhoods by field measurement and survey. This is a starting point to develop sustainable housing and neighbourhood typologies as adaptation to climate change in the city. The survey was conducted in the summer of 2016. The analysis of the survey data showed that the satisfaction level of local inhabitants with actual thermal condition was relatively high, and the perception of those living in various neighborhoods did not differ significantly. To monitor the comfort level during summer in houses of Ha Tinh city, nine houses were selected based on their typologies and locations represented by local climate zones (LCZs). The investigation was conducted from late August to mid-October 2017. With data obtained from the field measurement, psychrometric analysis was performed and based on modified adaptive comfort model for South-East Asian people to evaluate thermal condition of considered houses. The analysis evaluated and showed explicit difference in comfort level between these housing typologies. Result of the analysis also showed a dependence of thermal comfort in different rooms of a house on their position and exposition to solar heat gained, but relation of comfort level to LCZs was not clear.

Analysing the influence of urban planning on the financial and environmental impact of neighborhoods -- The ecological and conservative planning of traditional Vietnam-villages -- Socially inclusive and economically beneficial smart cities -- Affordable housing supply in Belgium – current situation -- Actual situation of high-rise office buildings in Vietnam and strategic development towards sustainability -- Interaction between innovative systems and buildings: a key factor for energy sustainability -- A review of residential grid-connected microgrid energy management strategies for grid power profile smoothing -- Linking neighborhoods into sustainable energy systems -- Wind energy -- Sustainable Cooling with Hybrid Concentrated Photovoltaic Thermal (CPVT) System and Hydrogen Energy Storage -- Energy sustainability through the use of thermoelectric materials in waste heat recovery processes applied to residential buildings -- Sustainability in ports: implementation of energy storage to reduce greenhouse gases emissions -- Novel method and molten salt electrolytic cell for implementing a hydrogen fuel, sustainable, closed clean energy cycle on a large scale -- Denmark on its way towards a 100% renewable energy-system -- Weather data for building energy performance in a context of climate change: literature review and future outlook -- Energy efficiency in residential buildings in Vietnam - high-tech or low-tech? -- Sustainable construction practices in West African countries -- The persistence of alternative energy mutual fund performance in Spanish market -- Community participation in urban planning for sustainable development in Vietnam- Prospect and Challenges -- Analyzing the alternative energy mutual funds’ performance in Spanish market.

In school and office buildings the ventilation system has a large contribution to the total energy use. A control strategy that adjusts the operation to the actual demand can significantly reduce the energy use. This is important in rooms with a highly fluctuating occupancy profile. However, a standard rule-based control is reactive, making the installation ‘lag behind’ in relation to the demand. A model predictive control (MPC) might be a solution. To implement an MPC control first a suitable model must be identified for reliable predictions of room temperature and CO2 concentration. For CO2 predictions three scenarios are proposed respectively counting camera, lecture schedule and motion sensor. Two model identification techniques are evaluated: ARX and RC models. For identifying the heating dynamics of the case study building the 3 state RC model showed a good performance, a 5 step ahead prediction on a 15 minute time interval indicated a RMSE of approximately 0.60 °C. The 3rd order ARX model indicated similar results, however the cross validation demonstrated that the RC model outperforms the ARX model. For CO2 predictions the counting scenario resulted in the most accurate n-step ahead predictions. The RMSE found for the RC model is at maximum 90 ppm while 140 ppm for the ARX model. RC models are recommended for modelling all-air HVAC systems attributed by the higher prediction accuracy over ARX models. In addition, these models still contain physical parameters compared to ARX models.

Unlike other types of buildings, commercial and industrial buildings have been so far “forgotten”. In addition, EPBD requirements are increasingly challenging for this type of buildings. This paper aims to identify the most building determinants of the energy performance of commercial and industrial buildings, focussing on the building envelope. Building energy simulations (BES) in TRNSYS are used to simulate the energy demand for heating and cooling in five building variants. The Pareto optimality approach that considers the economic and energetic objectives equally, is used to determine the cost-optimal solutions. The sensitivity analysis and cost-optimal study clearly reveal that airtightness seems to be the most important factor. Although heat recovery on a balanced mechanical ventilation system has a major impact on the energy demand for heating, this measure is not cost-optimal. The large impact of the U-value of the roof on the energy demand for heating is also reflected in the cost-optimal study. The insulation of the floor do not appear to be cost-optimal. Moreover, attention to construction detailing is important. The additional energy losses that can occur due to thermal bridges quickly reach significant values although solving the thermal bridges seems not to be cost-optimal.

Daylight control systems, which automatically adjust the artificial light levels depending on the daylight penetration, can result in substantial energy savings. However, their energy saving potential cannot be estimated accurately because it depends on several building and system parameters, climate conditions, occupant behaviour and type and commissioning of the daylight control system. The objective of this paper is to compare the energy saving potential and operation of different daylight control systems in school buildings. One year monitoring has been carried out simultaneously in 3 neighbouring classrooms, equipped with a different type of control system. The active power and the electric energy consumption of the artificial lighting were measured continuously on a minute-by-minute basis, as well as the occupancy of the classrooms and the global irradiance outside the building under an unobstructed horizon. Momentary visual comfort assessments were carried out in the classrooms. Although all classrooms have comparable occupancy and identical building characteristics, differences between the annual energy savings of the different daylight control systems are found to be significant: the total annual energy savings varied from 18% to 46%. Under the given conditions, the open loop system with the outward facing daylight sensor was noticed to yield the largest while the closed loop system with centrally positioned sensor produced the smallest savings. However, it has to be made sure that the energy savings are not at the expense of the visual comfort. The performance of the systems regarding both energy savings and visual comfort is related to the operation and the initial commissioning. An in-depth analysis of the monitoring campaign is discussed to explain the differences in energy savings and visual comfort. The energy savings due to the implementation of a daylight control system are divided into on the one hand dimming due to daylight penetration and on the other hand initial dimming to compensate for the over dimensioning of the lighting system and to take into account constant illuminance control.

In Flanders, an obligatory software tool (EPR) is used to assess the energy performance of new buildings offering a simplified procedure to estimate the energy use for heating. This calculation approach is based on the principle of multiplying the building’s heating demand with standardised (sub)system efficiencies. In this paper, the accuracy of this simplified approach is assessed for a traditional, hydronic heating system in non-residential buildings. To do so, integrated dynamic simulations are performed in TRNSYS for a series of building design variants with varying insulation quality, thermal capacity, window-to-wall ratio and orientation. From the integrated simulations, monthly subsystem efficiencies are deduced. Results show that the efficiencies are significantly influenced by the part load ratio. As however losses of efficiencies are noticed only in periods of low heat demands, the overall effect on the annual use is limited. Energy assessment by the simplified method is within an error of

Demand-controlled-ventilation (DCV) refers to a ventilation system with controlled air flow rate based on indoor air quality. DCV operates at reduced air flow rates during most of the operation time. Therefore, less energy is required for fan operation, compared to a constant-air-volume (CAV) ventilation system. Typically, DCV has a two-layer control with variable-air-volume (VAV) valves, and a fan speed control to maintain a constant-static-pressure in the duct system based on a pressure set point. However, this nominal design based fan pressure setpoint is higher than required when all VAV-valves are closed to a certain extent. Therefore, advanced pressure-reset (PR) control - resetting the pressure set point - potentially reduces fan energy use even further. This paper assesses the impact of fan control on both fan energy use and ventilation performance in DCV system of a densely occupied office. Results of a simulation model and realistic measurement setup are compared. The PR control, using air flow rate and VAV-valve position measurements as feedback, causes significantly reduction on fan energy use. These reductions compared to conventional DCV and CAV respectively, are approximately 10% and 72% in case of high occupancy and 50% and 93% in case of low occupancy. Largely, DCV with PR control is strongly considered, especially when occupancy is often expected to deviate significantly from the nominal conditions. Moreover, both simulations and measurements show that there is a clear trade-off between air flow rate deficit and fan energy use, when the fan energy use is lower, the air flow rate deficit is higher and vice versa. Furthermore, the results show that VAV-valve accuracy, characteristics and its lower operational limit hamper the ventilation system in achieving the predicted performance as in the simulation. ispartof: Energy and Buildings vol:174 pages:111-123 status: Published online

© 2015 The Authors. The use of timber frame constructions in dwellings is gaining popularity in Belgium. Continuous improvement of EPBD requirements causes a low heating demand resulting in an increasing risk on overheating in these lightweight dwellings. Designers lack easy-to-use guidelines ensuring robust thermal summer comfort. Therefore, a parametric study with building energy simulations (BES) is conducted for a typical Flemish (Belgian) dwelling. Main design parameters and the effect of boundary conditions are analysed. The results demonstrate the critical role of effective solar protection and increased ventilation rates during occupation. The significant impact of boundary conditions shows the sensitivity of the design parameters. publisher: Elsevier articletitle: Design Recommendations for Robust Thermal Summer Comfort in Residential Lightweight Buildings in a Moderate Climate journaltitle: Energy Procedia articlelink: http://dx.doi.org/10.1016/j.egypro.2015.11.643 content_type: article copyright: Copyright © 2015 The Authors. Published by Elsevier Ltd. ispartof: pages:2832-2837 ispartof: Energy Procedia vol:78 pages:2832-2837 ispartof: 6TH INTERNATIONAL BUILDING PHYSICS CONFERENCE (IBPC 2015) location:Torino date:14 Jun - 17 Jun 2015 status: published

In this paper, the feasibility of passive cooling in newly built office buildings in the temperate climate of Belgium is assessed using the standardized adaptive comfort criteria. This is done through Monte Carlo uncertainty analysis of the simulated weighted exceeding time for different building designs with varying insulation level, glazing-to-wall-ratio, glazing type and air tightness. Two passive cooling schemes are studied: diurnal manual window operation and the combination of diurnal manual window operation and passive night ventilation. Additionally, two possible measures to limit heat gains, external solar shading and daylighting, are considered. The integration of a detailed model of window operation, establishing a real-time coupling between the thermal model and the behavioural model and thus allowing simulating adaptive behaviour, is shown to impact the results significantly and is therefore recommended by the authors. The uncertainty analysis shows that it is possible to cool office buildings solely by diurnal manual window operation, even for highly insulated and air tight buildings. This requires minimizing heat gains to about 900 kJ/m 2 per working day during summer months. When a combination of diurnal window operation and night ventilation is available, limiting the heat gains to about 1500 kJ/m 2 per working day suffices.

The potential of night cooling, a passive cooling technique of growing interest, is typically investigated by numerical means. In particular multi-zone energy simulation is currently appraised for building design. Unfortunately, in addition to the inaccurate approximation of an ideally mixed room, the implemented empirical convective heat transfer coefficients (CHTCs) only apply to specific flow regimes – forcing to use arbitrary correlations and, thus, possibly limiting the usefulness of the simulation results. Therefore, the authors of this paper investigate the sensitivity of the night cooling performance to convection algorithms. First, the authors examine the applicability of convection correlations for real building enclosures, extracted from literature. Subsequently, simulations of a night cooled office room during summertime of a moderate climate (Belgium) are carried out in TRNSYS, using different convection correlations in addition to varying design parameters. The results show that the choice of the convection algorithm strongly affects the energy and thermal comfort predictions. More importantly, the convection algorithm is of the same importance as the design parameters – making an exact definition of the CHTC crucial. Therefore, additional research by experiments or airflow codes, based on fluid dynamics, is regarded necessary.

Natural night ventilation is an interesting passive cooling method in moderate climates. Driven by wind and stack generated pressures, it cools down the exposed building structure at night, in which the heat of the previous day is accumulated. The performance of natural night ventilation highly depends on the external weather conditions and especially on the outdoor temperature. An increase of this outdoor temperature is noticed over the last century and the IPCC predicts an additional rise to the end of this century. A methodology is needed to evaluate the reliable operation of the indoor climate of buildings in case of warmer and uncertain summer conditions. The uncertainty on the climate and on other design data can be very important in the decision process of a building project. The aim of this research is to develop a methodology to predict the performance of natural night ventilation using building energy simulation taking into account the uncertainties in the input. The performance evaluation of natural night ventilation is based on uncertainty and sensitivity analysis. The results of the uncertainty analysis showed that thermal comfort in a single office cooled with single-sided night ventilation had the largest uncertainty. The uncertainties on thermal comfort inmore » case of passive stack and cross ventilation were substantially smaller. However, since wind, as the main driving force for cross ventilation, is highly variable, the cross ventilation strategy required larger louvre areas than the stack ventilation strategy to achieve a similar performance. The differences in uncertainty between the orientations were small. Sensitivity analysis was used to determine the most dominant set of input parameters causing the uncertainty on thermal comfort. The internal heat gains, solar heat gain coefficient of the sunblinds, internal convective heat transfer coefficient, thermophysical properties related to thermal mass, set-point temperatures controlling the natural night ventilation, the discharge coefficient C{sub d} of the night ventilation opening and the wind pressure coefficients C{sub p} were identified to have the largest impact on the uncertainty of thermal comfort. The impact of the warming climate on the uncertainty of thermal comfort was determined. The uncertainty on thermal comfort appeared to increase significantly when a weather data set with recurrence time of 10 years (warm weather) was applied in the transient simulations in stead of a standard weather data set. Natural night ventilation, designed for normal weather conditions, was clearly not able to ensure a high probability of good thermal comfort in warm weather. To ensure a high probability of good thermal comfort and to reduce the performance uncertainty in a warming climate, natural night ventilation has to be combined with additional measures. Different measures were analysed, based on the results of the sensitivity analysis. All the measures were shown to significantly decrease the uncertainty of thermal comfort in warm weather. The study showed the importance to carry out simulations with a warm weather data set together with the analysis under typical conditions. This approach allows to gain a better understanding of the performance of a natural night ventilation design, and to optimize the design to a robust solution. (author)« less

© 2014 Elsevier B.V. All rights reserved. Building energy assessment methods, used in a regulatory context, impose a calculation procedure under restricted and predefined conditions to check preset energy performance levels. Standardized boundary conditions and input data are implemented allowing for objective evaluation of various building designs. Focusing on school buildings in particular, these specific boundary conditions are however often inaccurate or even unavailable. Therefore, throughout this paper, typical school characteristics and their uncertainty are studied. The impact on the energy demand calculations is then demonstrated in an uncertainty analysis using the Monte Carlo analysis method combined with the Latin Hypercube sampling technique. A sensitivity analysis, using the elementary effect method of Morris, reveals the set point temperature, load and users' profiles of lighting and equipment in class rooms as the most dominant input parameters on which additional surveys and questioning are focused to determine possible inaccuracies and to define, where necessary, new, more realistic boundary conditions. As a final result, a list of representative boundary conditions for Flemish schools is determined which can be used directly or can be converted into averaged input data for simplified calculation methods. publisher: Elsevier articletitle: The definition of representative boundary conditions for Flemish schools for use in energy assessment methods journaltitle: Energy and Buildings articlelink: http://dx.doi.org/10.1016/j.enbuild.2014.10.033 content_type: article copyright: Copyright © 2014 Elsevier B.V. All rights reserved. ispartof: Energy and Buildings vol:87 issue:1 pages:1-13 status: published

The quasi steady-state calculation method (based on EN ISO 13790) is commonly used for energy performance checking. This method attempts to accurately represent the building's energy use. However, intermodal comparison of dynamic and static calculations reveals quite some discrepancies often caused by the inaccuracy of the gain utilization factor and the temperature setback approach used for intermittently heated buildings. This paper tries to improve the method for schools buildings focusing on the gain utilization factor η H,gn and the parameters a 0 and τ 0 in particular. These parameters will be adapted to the Flemish climate and the typical characteristics of school buildings. The Monte Carlo analysis technique is applied to cover the broad spectrum of influential parameters. Based on the comparison of dynamic and static calculation results, a regression analysis is performed to determine the correlation between the heat-balance ratio γ H and the gain utilization factor η H,gn. Although more accurate results are found using the adapted dynamic parameters a 0 = 1.4 and τ 0 = 185, the quasi steady-state method for school buildings remains unreliable as the accuracy of the method is simultaneously determined by the value of the gain utilization factor and by the assessment of the adjusted set-point temperature. © 2013 Elsevier B.V. All rights reserved. publisher: Elsevier articletitle: Evaluation of the accuracy of the implementation of dynamic effects in the quasi steady-state calculation method for school buildings journaltitle: Energy and Buildings articlelink: http://dx.doi.org/10.1016/j.enbuild.2013.05.046 content_type: article copyright: Copyright © 2013 Elsevier B.V. All rights reserved. ispartof: Energy and Buildings vol:65 pages:173-184 status: published

In office buildings, the use of passive cooling techniques combined with a reduced cooling load may result in a good thermal summer comfort and therefore save cooling energy consumption. This is shown in the low-energy office building ‘SD Worx’ in Kortrijk (Belgium), in which natural night ventilation and an earth-to-air heat exchanger are applied. In winter, the supply air is successively heated by the earth-to-air heat exchanger and the regenerative heat exchanger, which recovers the heat from the exhaust air. In summer, the earth-to-air heat exchanger cools the ventilation air by day. In addition, natural night ventilation cools down the exposed structure which has accumulated the heat of the previous day. In this article the overall thermal comfort in the office building is evaluated by means of measuring and simulation results. Measurements of summer 2002 are discussed and compared to simulations with a coupled thermal and ventilation simulation model TRNSYS-COMIS. The simulations are used to estimate the relative importance of the different techniques. The evaluation shows that passive cooling has an important impact on the thermal summer comfort in the building. Furthermore, natural night ventilation appears to be much more effective than an earth-to-air heat exchanger to improve comfort. In office buildings, the use of passive cooling techniques combined with a reduced cooling load may result in a good thermal summer comfort and therefore save cooling energy consumption. This is shown in the low-energy office building ‘SD Worx’ in Kortrijk (Belgium), in which natural night ventilation and an earth-to-air heat exchanger are applied. In winter, the supply air is successively heated by the earth-to-air heat exchanger and the regenerative heat exchanger, which recovers the heat from the exhaust air. In summer, the earth-to-air heat exchanger cools the ventilation air by day. In addition, natural night ventilation cools down the exposed structure which has accumulated the heat of the previous day. In this article the overall thermal comfort in the office building is evaluated by means of measuring and simulation results. Measurements of summer 2002 are discussed and compared to simulations with a coupled thermal and ventilation simulation model TRNSYS-COMIS. The simulations are used to estimate the relative importance of the different techniques. The evaluation shows that passive cooling has an important impact on the thermal summer comfort in the building. Furthermore, natural night ventilation appears to be much more effective than an earth-to-air heat exchanger to improve comfort. ispartof: Solar Energy vol:79 issue:6 pages:682-696 status: published

Current HVAC control systems assume occupant-related information, i.e., preferences, occupancy and behaviour. Furthermore, occupants often have limited control over the indoor environment in non-residential buildings. As a result, occupants are often dissatisfied with the indoor environmental quality (IEQ). This study works towards defining a novel occupant-centric control (OCC) framework which integrates occupants’ feedback regarding their satisfaction with the IEQ. This study collected both occupant satisfaction assessments via surveys and IEQ measurement data in various case studies. The collected data is used to (1) determine the statistical relationships between occupant satisfaction and IEQ and (2) develop personalized models to predict occupants’ satisfaction with IEQ. Afterwards, the developed personalized models will be integrated in an occupant-centric controller. A suitable consensus strategy, seeking the most optimal conditions in case of conflicting occupant preferences, is determined to make the OCC system applicable in multi-occupancy spaces, such as, classrooms and open-plan offices. ispartof: pages:224-225 ispartof: The Book of Proceedings of the 42nd AIVC - 10th TightVent - 8th venticool Conference: "Ventilation Challenges in a Changing World" held in Rotterdam, Netherlands on 5-6 October 2022 pages:224-225 ispartof: 42nd AIVC - 10th TightVent - 8th venticool Conference - "Ventilation Challenges in a Changing World" location:Rotterdam, Netherlands date:5 Oct - 6 Oct 2023 status: Published online