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Abstract The central role of occupants for achieving energy savings in residential buildings is increasingly recognised. Simulation programmes able to take into account occupant behaviour are considered to be powerful tools for bridging the gap between the predicted and the actual energy consumption for new buildings. Nevertheless, the majority of residential buildings that will constitute the housing stock in 2050 have already been built today, therefore occupant behaviour and building simulation tools need to be fully exploited for supporting the renovation of existing housing stock. The aim of this paper is to explore the role of occupant behaviour modelling in supporting decision-makers dealing with the design of renovation strategies for residential buildings. An Italian multi-family public housing building is assumed as case study to estimate the influence of three dimensions linked with occupant behaviour – management of the thermostat, management of the heating system, variation of building characteristics – on energy heating consumption. The results show that, while the occupant behaviour influences the heating loads up to 1/3 in case of high level of building retrofit, the less the building is renovated, the higher is the behavioural impact in absolute terms of energy reduction. Therefore, in order to be effective, renovation strategies are required to design appropriate informative instruments at an early stage to support behaviour changes towards responsible energy consumption.

Abstract In recent years living walls have increasingly spread, thus becoming a diffuse architectural envelope cladding technology. Consequently, a more precise understanding of their thermal behavior and impact on the building energy balance are needed. One of the most important effects provided by the use of living walls is the shading of the building envelope, with clear benefits during the cooling period. Furthermore, many features characterize the thermal behavior of living walls, namely plant species, leaf area index (LAI), evapotranspiration, emissivity and air cavity type. All these particular characteristics have been accounted in the mathematical model developed in the frame of the presented research, whose aim is to provide a tool for the prediction of the thermal behavior of living walls. Two kinds of living walls, one with grass and closed air cavity and the other one with vertical garden and open air cavity were considered. The results achieved by means of the developed model show a good agreement with the measurements also supported by model efficiency indexes such as Nash–Sutcliffe efficiency index (NSEC). Values of around 0.7 were obtained for the NSEC index for both the investigated living walls.

The TOBUS software has been developed to facilitate the implementation of the TOBUS building diagnosis and decision-making method for retrofit studies. This user-friendly software runs under the Windows® operating system and includes several modules, each of which addresses a particular aspect of the diagnosis including: building description, dimensions, cost coefficients, building diagnosis of current physical state and functional obsolescence, indoor environmental quality (IEQ), energy use, elaboration of retrofit scenarios, cost analysis, reporting results. The software also includes comprehensive databases on the physical state of degradation, including hundreds of illustrations, retrofit work details, cost, etc.

Abstract Dynamic modeling of HVAC system is extremely important for control analysis toward building energy saving. In order to provide researchers a simulation platform to analyze different control strategies, this paper introduces a simulation platform with customized Simulink block library based on dynamic HVAC component model. As an initiating effort, the current simulation platform is composed of basic modular HVAC components, including conduit, damper/valve, fan/pump, flow merge, flow split, heating coil, cooling coil, and zone. These modules are developed into Simulink customized blocks. The simulation platform is capable to calculate the flow rates of fresh air, exhaust air, and return air based on system characteristic and fan curve with customizable basic/advanced control strategies. A case study is proposed using single-zone, constant volume system by comparing the uncontrolled, fixed temperature and damper position controlled, and schedule based reset controlled cases. The simulation result proves that schedule based temperature and damper position reset has a significant impact on energy saving for both heating and cooling seasons. This simulation platform can be especially useful for analyzing the dynamic performance of different HVAC control strategies.

Abstract A new method for providing ventilation in large enclosures, which utilizes the principle of ‘selective withdrawal’ of contaminants while ensuring energy-efficiency and allowing a better use of space, is presented in this study. The concept is based on dividing the enclosed space ventilation-wise into separate zones using a combination of horizontal partitions by stratification and vertical partitions by temporary walls. This gives a high degree of flexibility in the use of available space. The relative influence of all the parameters on the flow patterns inside an enclosure is discussed in order to identify the design parameters that should be controlled to apply the technique successfully. An experimental study in a scale model was conducted, which provided a better understanding of the physical processes that occur in such enclosures. The influence of exhaust location on the flow field was studied in particular. It was found that by controlling the position of exhaust the stratification effects are enhanced and maintained at a desired level in order to achieve a successful utilization of the selective ventilation system.

This study investigates the feasibility of a device to improve summer comfort in wood-frame houses using a Ventilated Internal Double Wall (VIDW). The idea is to increase the house's thermal inertia and to evacuate accumulated heat during the night with a mechanical ventilation system. The VIDW is a cooling wall. Numerous studies on night ventilation have been conducted, but the active ventilation inside the air gap of a double wall with high thermal inertia has not been studied. The first part of this study examines the impact of VIDWs on the thermal comfort in a timber-frame house. The VIDW is modeled in transient mode based on an electrical analogy with the assumption that the exchange coefficients are constant for a given air velocity. In addition, modeling a stationary CFD in forced convection of the VIDW air gap allowed us to study the cooling potential and the benefit of installing obstacles.