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Nursing homes are designed and operated to meet general thermal specifications outlined by existing standards. This paper presents adaptive thermal comfort models for nursing homes based on the field survey administered in 100 common rooms of five nursing homes in the Mediterranean climate. The survey included simultaneous measurements of outdoor and indoor environmental parameters and an assessment of the occupants’ thermal comfort sensations using questionnaires. In total, 1,921 subjective questionnaires were obtained. The analysis focused on: Building Operation Mode (naturally ventilated and air-conditioned mode (cooling and heating)); and type of occupant (residents and non-residents (caregivers and therapists)). In naturally ventilated rooms residents were found to be more adaptive than what EN and ASHRAE 55:2020 standards propose (Tc (naturally ventilated) = 0.26 Trm + 18.83 (R2 = 0.81)). Residents in air-conditioned rooms were found to be less sensitive to outdoor conditions (Tc (air-conditioned) = 0.16Trm + 20.41 (R2 = 0,91)) than in naturally ventilated rooms. Both adaptive thermal models fall in limits set by these standards but in the lower acceptable levels. These adaptive thermal comfort models for nursing homes will allow extending the use of natural ventilation and the adoption of setpoint temperatures when air-conditioning is needed with the consequent reduction of heating and cooling use. The authors thank the International Center on Aging (CENIE), the General Foundation of the University of Salamanca (FGUSAL) and the Programa de Cooperación Interreg V-A España – Portugal (POCTEP) 2014-2020 and the FEDER funds for their financial support of this study under project reference 6/2018_CIE_6. This research was also supported by the Spanish Ministry of Economy, Industry and Competitiveness under R&D project Thecoelen, reference no. PID2019-106777RB-C21. We would also like to thank Sanitas Mayores and specially the Eng. Marc Vallet and Eng. Albert Ayala for providing their nursing homes and helping to collect all the required data. We would also like to extend our appreciation to all the caregivers, maintenance staff and elderly people who participated in this project. Peer Reviewed

Abstract As the size of buildings and demands on large centralized heating and cooling systems increases concurrent with rapid worldwide urbanization, the energy impact of hydronic distribution systems will become increasingly important in reducing greenhouse gas emissions. Further, in the U.S., the growth in multi-family buildings and the share of residential units in large multifamily buildings is far outpacing single-family construction. This paper describes a study of the pumping energy requirements of an urban 23-story mixed-use, primarily multifamily residential building before and after a suite of energy conservation measures. The retrofit focused on waterside technologies: Variable frequency drives (VFDs), constant and variable speed pumps, and pressure-independent control valves. In the original building, the central pumping equipment was found to be responsible for 55% of total annual owner-metered electricity usage and 29% of all annual owner-paid utility bills. Using extensive in-situ monitoring and analytical models developed for this effort, the full retrofit was computed to achieve a 41% reduction in annual central pumping electricity, representing an annual savings of 12% of all owner-paid energy bills. The most significant energy impact is attributable to the VFDs, and it can be inferred that additional savings could be achieved by installing VFDs on constant speed pumps.

Abstract Driven by wind and buoyancy effects in the urban environment, ventilation performance and pollutant transmission are highly related to human health. In order to investigate characteristics of the single-sided natural ventilation and interunit dispersion problem, this study conducted scaled outdoor experiments in summer and winter periods in two-dimensional street canyons. Tracer gas method was adopted to predict the ventilation rate and simulate the pollutant dispersion. It was found the ventilation performance of windward and leeward rooms showed different trends with wind velocities. Archimedes number Ar was used to examine the interactions of the buoyancy and the wind forces. It revealed that the non-dimensional ventilation rates of all rooms were generally smaller than the results of buoyancy effect only. It indicates that interactions between the buoyancy and wind effects were destructive, which reduced the ventilation rates. The interunit dispersion characteristics with the wind effect were highly dependent on source locations. The results of the tracer gas concentrations of the reentered rooms were not showing simple increasing or decreasing trends. This study provides authentic and instant airflow and pollutant dispersion information in an urban environment. The dataset of this experiment can offer validations for further numerical simulations.

Abstract Lighting is the highest consumer of electrical energy in office buildings and it is one of the areas that offer many opportunities for improving the energy efficiency thereby reducing the energy consumption. This paper presents control strategy for energy efficient office lighting system design. The energy efficiency of a typical office building lighting system in Dubai is examined in this paper. The impact of use of natural lighting and artificial lighting on the HVAC system is assessed and highlighted. Lighting control algorithm is developed with the ultimate goal of achieving energy efficiency and health aspects of occupants into consideration. It is simulated using control systems simulation software functional explorer (FX) tools and recommendations are forwarded. The proposed control algorithm can be used as a reference to other new buildings to be built in Dubai or Middle East in general.

Abstract Renewable energy utilisation, latent energy storage, optimal system design, and robust system operation are critical elements for carbon-free buildings and communities. Machine learning methods are effective to assist the energy-efficient renewable systems during multi-criteria design and multi-level uncertainty-based operation periods. However, the current literature provides little knowledge on this topic. In this study, a state-of-the-art-review on phase change materials for cooling applications is presented, in terms of smart ventilations, intelligent PCMs charging/discharging, deterministic parametrical analysis, stochastic uncertainty-based performance prediction and optimisation. Furthermore, technical effectiveness of machine learning methods in single and multi-objective optimisations has been presented, through hybrid PCMs integrated renewable systems. Multivariables involved in the review include thermo-physical, geometrical and operating parameters of PCMs. Multi-criteria employed in the review include heat transfer rate, cooling energy storage density, heat storage and release efficiency, and indoor thermal comfort. The literature review presents technical challenges, such as tradeoff solutions between computational accuracy and efficiency, generic methods for effective selection amongst multi-diversified optimal solutions along the Pareto front, the general methodology for multi-level uncertainty quantification, smart controllers with accurate predictions under high-level parameters’ uncertainty and stochastic occupants’ behaviors. The future outlook and recommendations of machine learning methods in PCMs integrated cooling systems have also been presented as avenues for upcoming research.

Abstract The replacement of old equipment in multi-residential apartment buildings with bearing-wall structural systems requires demolition and reconstruction. Several issues arise when performing such tasks, including the degradation of the urban environment, the wasting of resources, and the generation of construction waste. As a potential solution to these issues, a hybrid composite structural system for use in an apartment building was proposed. This system provides a level of architectural flexibility that is not offered by a conventional bearing-wall structure. The architectural flexibility extends the service life of apartment buildings by reducing the need for demolishing and reconstructing bearing-wall apartment buildings. In addition, the alternative system maximizes the efficiency of material use through the optimized relocation of structural steel, cast-in-place concrete, and precast concrete, thereby reducing material quantities and minimizing CO 2 emissions. When compared to a conventional bearing-wall apartment, the hybrid composite system consisting of structural steel, cast-in-place concrete, and precast concrete is expected to improve energy efficiency during construction. In this work, the results of analytical and experimental investigations of a hybrid composite beam to be used in multi-residential apartment buildings are presented. The beam was found to yield enhanced energy efficiency when compared to a conventional bearing-wall apartment. The developed analytical prediction method based on the strain compatibility theory was validated by experiment.

Data availability: Data will be made available on request. ; Copyright © 2023 The Author(s). Urban settings and climate change both impact on energy use and thermal comfort inside buildings. This paper first presents a study of changes in energy demand in residential buildings considering the overlapping effect of climate change and urban heat island intensity in two European locations; Cadiz (Spain) and London (United Kingdom), representing temperate and hot European climates and moderate and dense urban settings. Future-urban weather files were generated and simulations were run considering energy demand and indoor thermal comfort. In hot climate regions such as the one of Cadiz, future climate will increase the cooling demand and the additional impact of the UHI leads to a further increase of up to +28% of total energy demand compared to the current climate without considering urban effects. Future-urban weather conditions will be detrimental also for buildings in London, where the annual energy demand is predicted to increase by up to the 16% if future climate and urban effects are included. This is due to a higher increase in cooling demand compared to the reduction for the heating need. The paper also presents a method to take into account microclimatic conditions in naturally ventilated buildings, especially the effect of wind variations around the building which impacts natural ventilation rates. Air and surface temperature and wind speeds were studied using ENVImet and the resulting microclimatic conditions were used as inputs to the EnergyPlus Airflow Network model for the calculation of the building ventilation rates. It was found that ventilation rates are reduced (in comparison to meteorological weather files) and this reduction impacts negatively on internal operative temperatures. A thermal comfort analysis was carried out indicating that the selection of a suitable weather file and microclimatic conditions is essential for more accurate predictions of internal thermal comfort and will assist in ...

Abstract With the rise of awareness of health and well-being in cities, urban environmental analysis should expand from energy performance to new environmental quality-based considerations. The limited potential to annually evaluate outdoor thermal comfort, predominant among these considerations, has restricted the exploration of the interrelations between urban morphology and annual energy performance. This study aims to bridge this gap by capitalizing on the new capabilities of Eddy3D – a Grasshopper plugin which enables effective calculations of hourly microclimatic wind factors via OpenFOAM which in turn are used to generate annual outdoor thermal comfort plots. Using this method, a parametric study was conducted for different typology and density scenarios in three different hot climatic contexts in Israel. The automated analytical workflow evaluated a total of 60 design iterations for their energy balance, outdoor thermal comfort autonomy (OTCA) and self-shading levels using the shade index. The high correlation found here between the annual shade index and the OTCA, across all climatic contexts, shows the potential of the shade index to serve as an effective indicator, in these contexts, for comparative or optimization outdoor comfort studies. Further results are both the superiority of the courtyard typology in both energy and outdoor comfort studies, and the contrasting impact of higher density on the annual energy balance (lower performance) and outdoor thermal comfort (higher performance) in hot climates. The annual plots of both the energy balance and OTCA reveal various seasonal and monthly trends in the three different climatic zones which can lead to localized and seasonal urban design strategies.

Abstract This paper empirically investigates the influence of building fabric, services and occupant related factors on actual energy use of six case study dwellings, located in three new low energy social housing developments in UK, covering a variety of built forms and construction systems (timber frame, hempcrete, steel-frame). Physical monitoring of indoor environment and window-opening is cross-related with building fabric and systems’ performance, and qualitative data gathered through occupant surveys, review of control interfaces and handover guidance, to understand the causes of the gap between modelled and measured energy use. Actual energy use is found to exceed design expectations by a factor of three, questioning the need for whole-house mechanical ventilation heat recovery (MVHR) systems at measured air permeability rates of 6 m³/(h.m²) against the design target of 3 m³/(h.m²). Lack of proper commissioning of MVHR and heating systems, combined with inadequate user comprehension about their operation and control leads to occupant ‘misuse’ wherein systems are de-activated, thereby negatively affecting indoor air quality. This is confounded by occupant factors related to higher demand temperatures, unexpected opening of windows during winters due to under-performance of MVHR combined with habitual behaviours, and over-use of heating systems to compensate for higher than expected air permeability.