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Thermal comfort is a primary concern of building design. Accurate and rapid methods are needed to assess thermal comfort in non-air-conditioned buildings. In this work, a new flexible metamodel was developed for assessing long-term thermal comfort in non-air-conditioned buildings. Using five different indices, the metamodel was used to study the thermal comfort in an office during summer for two typical cold and hot European climates. The metamodel was fitted by multiple regression analysis with a low number of dynamic simulations using the design of experiments. A good fit was obtained for indices, such as maximum indoor temperature, that are consistently sensitive to the influencing factors. For the remaining indices, such as overheating degree-hours, the accuracy was dependent on the location and thermal mass of the building. An interpolation method was proposed that can be used when the metamodel fit is not good. This method gave accurate results with all the indices (R2 > 0.98) when the values were obtained from the mean indoor temperature without additional computational efforts. The proposed metamodel could be used to rapidly assess long-term thermal comfort and to understand the relationships between building design and indoor thermal conditions. [ABSTRACT FROM AUTHOR]

Buildings could actively participate in the emerging smart electrical grid if they were able to incorporate dynamic modulations of indoor temperature set-points. But the mechanisms of dynamic thermal perception remain relatively poorly understood and we are still far from being able to design and control temperature fluctuations that would be comfortable for occupants. In this paper, we review the current state of knowledge on thermal comfort during non-steady state conditions. We especially focus on the psycho-physiological phenomena of thermal alliesthesia and thermal habituation, both of which are known to affect the dynamic thermal perception but have received scant attention in previous reviews and are yet to be fully characterized. By drawing from experimental literature (1960 through 2021) on thermal comfort under transient conditions and from recent neurophysiological evidence, we identify major knowledge gaps in the domain of dynamic thermal perception and set future research needs required to fill these gaps. [Display omitted] • Basics of thermal perception described. • Phenomena of thermal alliesthesia and thermal habituation characterized. • 46 dynamic thermal comfort experiments systematically reviewed. • 10 open research questions on dynamic thermal perception identified. • An agenda for future research prioritised. [ABSTRACT FROM AUTHOR]

Abstract: Free-cooling by ventilation is one of the most energy efficient techniques for cooling. When ventilation is used for cooling, variable airflow rates should to be used in order to achieve comfortable room temperatures and to minimize the energy demand for mechanical ventilation. Thus, free-cooling, requires, obviously, the existence of a potential for cooling and needs control mechanisms for the airflow. In this study, the free cooling potential by ventilation for office buildings is evaluated by the free-running temperature. The free-running temperature approach is based on the energy balance of heat gains and losses. It is adapted to evaluate the potential for free cooling by ventilation of office buildings for which the gains through the walls are negligible as compared to the internal and solar gains. The free-running temperature of each office room considers solar and internal heat gains, outdoor temperature, indoor temperatures and ventilation air flow rates. The approach is applied to 14 office rooms in a passively cooled office building in Germany and is used to estimate the potential and to evaluate the total energy saving by free cooling by ventilation. The good fit between monitoring data and calculation procedure proves that the free cooling potential can be accurately estimated by using the difference between the comfort limits, i.e. the target value of the indoor temperature, and the free-running temperature. [Copyright &y& Elsevier]

This study presents a multi-criteria method used for analysing the quality of an air-conditioned indoor environment. Indoor air flow induced by an actual Heating Ventilation and Air Conditioning system was experimentally studied under various conditions. The attention was focused on thermal comfort, acoustical comfort and indoor air distribution by considering spatial statistic studies of comfort indices. The compounded electric power of fan, compressor and pumps was measured in order to get information about energy consumption. A first analysis of these parameters showed that indoor comfort cannot be described by a general law. Thus, to reach the objective of a global approach of comfort by a spatial statistical study of the various discomforts, a multi-criteria analysis based on ELECTRE II method adapted to the comfort of air-conditioned indoor environment was applied. In this way the operating rules for coherent air conditioning systems can be defined, with a requirement for quality of indoor environment. [Copyright &y& Elsevier]

With increasing mean and extreme temperatures due to climate change, it becomes necessary to use—not only future typical conditions—but future heatwaves in building thermal simulations as well. Future typical weather files are widespread, but few researchers have put together methodologies to reproduce future extreme conditions. Furthermore, climate uncertainties need to be considered and it is often difficult due to the lack of data accessibility. In this article, we propose a methodology to re-assemble future weather files—ready-to-use for building simulations—using data from the European Coordinated Regional Downscaling Experiment (EURO-CORDEX) dynamically downscaled regional climate multi-year projections. It is the first time that this database is used to assemble weather files for building simulations because of its recent availability. Two types of future weather files are produced: typical weather years (TWY) and heatwave events (HWE). Combined together, they can be used to fully assess building resilience to overheating in future climate conditions. A case study building in Paris is modelled to compare the impact of the different weather files on the indoor operative temperature of the building. The results confirm that it is better to use multiple types of future weather files, climate models, and or scenarios to fully grasp climate projection uncertainties. [ABSTRACT FROM AUTHOR]

Abstract: The main objective of this study is to develop and test hybrid ventilation systems and control strategies that are suitable for residential buildings. Two ventilation systems were modelled: a mechanical extract ventilation system (called the reference system) and a hybrid low pressure ventilation system that can support two different types of demand control strategies (occupancy detection and CO2 concentration). The newly developed models were assembled with the existing thermal models of the SIMBAD Building and HVAC Toolbox developed by the CSTB. A single family house located in Athens (Greece), Nice (France), Trappes (France) and finally Stockholm (Sweden) was considered as the case study. Yearly simulations were performed to assess the performance of the hybrid ventilation control strategies. The assessment criteria used are related to indoor air quality, thermal comfort, energy consumption and stability of control strategies. The results show that the low pressure ventilation system can improve the indoor air quality and reduce the fan energy consumption compared to the reference system while maintaining the same building energy consumption for heating. [Copyright &y& Elsevier]

Abstract: The beneficial influence of trees and water ponds on summer comfort in urban spaces was studied experimentally in situ and in wind tunnels but the modeling needs further development to become effective in practical applications. This paper introduces a numerical approach based on coupling the CFD model of airflow, in which the influence of trees is considered as source terms, and the radiation exchange, completed with thermal conduction. The CFD, radiation and thermal conduction models use the same discretization grid at their common boundaries. The model was used to estimate the influence of trees and water ponds in a real town square. Comparison of results between two situations, with and without vegetation and water pond, indicate that surface temperatures are reduced in presence of trees and the comfort is improved. [Copyright &y& Elsevier]