Comfort Point Of View Research Articles

Integration of PV Systems into the Urban Environment: A Review of Their Effects and Energy Models

Building integrated photovoltaics (BIPVs) consist of PV panels that are integrated into a building as part of its construction. This technology has advantages such as the production of electricity without necessitating additional land area. This paper provides a literature review on recent developments in urban building energy modelling, including tools and methods as well as how they can be used to predict the effect of PV systems on building outdoor and indoor environments. It is also intended to provide a critical analysis on how PV systems affect the urban environment, both from an energy and a comfort point of view. The microclimate, namely the urban heat island concept, is introduced and related to the existence of PV systems. It is concluded that urban building energy models (UBEMs) can be effective in studying the performance of PV systems in the urban environment. It allows one to simultaneously predict building energy performance and microclimate effects. However, there is a need to develop new methodologies to overcome the challenges associated with UBEMs, especially those concerning non-geometric data, which lead to a major source of errors, and to find an effective method to predict the effect of PV systems in the urban environment.

Evaluation of Tactile and Thermophysiological Comfort in Reusable Surgical Gowns Compared to Disposable Gowns

Though the transition from disposable to reusable surgical gowns holds substantial promise, successful implementation faces challenges. This study investigated tactile and thermophysiological comfort in surgical reusable gowns, comparing them with their disposable counterparts. Parameters such as surface roughness, compression, heat flux, and material rigidity were tested using a Fabric Touch Tester. Additionally, the water vapour permeability and static charge of the gowns were assessed. Thermophysiological comfort of the gowns was evaluated by measuring the temperature and relative humidity (RH) on test subjects during wear trials where they were engaged in an activity that mimics a surgeon’s performance. Skin temperature was monitored using iButton sensors and a thermal camera, and the impact on heart rate during the task was analysed. Following each test, participants provided subjective feedback through a questionnaire. The results indicated that reusable gowns boasted a smoother texture, translating to reduced friction on the skin and better heat transfer compared to the disposable fabrics, as indicated using FTT. They also exhibited higher water vapour permeability compared to their disposable counterparts. The wear trials revealed minimal differences in comfort between disposable and reusable gowns. While performing the activity, an increase in body temperature led to decreased RH, yet this rise did not adversely affect subject comfort, as validated using heart rate and questionnaire survey data. From a comfort point of view, switching from disposable to reusable gowns would not have drawbacks, meaning hospitals should be able to switch provided logistics and costs can be managed.

Evaluation of Architectural Design Features in Achieving Sustainability in Hospital Projects

Newly built hospitals need to be assessed to evaluate the performance in the context of sustainability by means of comparing the thermal comfort level of the users and the ambient thermal conditions in hospital environment of high- and low-level designs. A perspective of facility management has been used to decide the responsibility of hospital administrators towards contributing for sustainable design outcome in order to make operational sustainable hospital with newly and restructured construction. To asses this, study data was extracted by using thermal environment equipment and energy simulation applications, through conducting survey of thermal comfort and interviewing authoritative personnel who provide services and care, facility provider and patients. The hypothesis suggests about how sophisticated sustainable ventilation design provisions provide a feel-good fact or from thermal comfort point of view and it helps to push down lower heat index in the wards that are designed with natural ventilation features.

Experimental evaluation of induced human walking vibrations on steel-concrete composite floors

abstract: This work presents the experimental evaluation of the dynamic behavior of Steel and concrete composite floors, from a human comfort point of view, when submitted to human walking. The structural model investigated was a real composite floor system under construction, with a total area of approximately 1300 m2. A preliminary numerical model was developed in order to guide the ideal positioning of excitation and instrumentation to be adopted in the experimental “in situ” evaluation. Next, free vibration tests were carried out to obtain the modal parameters of the structure. More than 180 forced vibration tests with excitation caused by a person walking at different step frequencies and directions were performed to determine de maximum structure’s response. The results found were compared with human comfort criteria recommended by national and international standards and design guides. Subsequently, a people quantity influence analysis on the dynamic response of the floor was carried out, where it was noticed that the increase in the number of users walking on the floor also increased the peak acceleration value. This fact emphasizes the need to carry out experimental evaluations considering the variation of people quantity on floor activity in order to evaluate the real scenario of human vibrations induced in the structure under service.

On Optimal Control of Multichamber Suspensions

This paper deals with the technological analysis, and optimal control of multi-chamber suspensions for automotive applications. Multichamber suspensions are composed by a variable damping shock absorber and an air-spring equipped with at least an auxiliary volume. The auxiliary volume is connected to the air-spring main chamber through a two-state valve. This configuration allows for a rapid change of both the damping and the stiffness of the suspension. The first goal of this paper is to model and analyze the behaviour of the suspension, the second goal is to investigate the potential benefit of this architecture from the comfort point of view. To this aim, the paper proposes an optimal benchmark controller and tests it in simulation showing comfort improvements up to 16% with respect to state-of-the-art solution of a passive soft spring and semi-active damping control.

Automated optimization for the integrated design process: the energy, thermal and visual comfort nexus

Nowadays, the design of energy efficient and comfortable building results as the solution to a complex optimization that involves a great number of interdependent variables. In such a complex system that is characterized by many requirements, sometimes conflicting, the use of an integrated design approach can speed up the design process, allow evaluating and comparing a great number of design options and lead to optimized performance at multiple levels.We present the conception of a replicable methodology, including the integrated tools and metrics, for supporting the integrated design of the building envelope, aiming at minimizing the building total energy demand (resulting from the sum of heating, cooling and lighting energy needs) in a thermal and visual comfort context. The methodology relies on a simulation-based optimization process. For each of the two thousand of design solutions that are analyzed within the design space of the problem, the thermal and visual comfort conditions are evaluated at the same time. A “filter” approach is used for combining the different objectives.The methodology is applied to the design of a school classroom as a reference case study. Results are compared for four different building orientations and two different climatic conditions. The differences in design between the optimized building configurations in the different location and orientation emerge from the study, however resulting in similar energy performance (total primary energy demands in the range 78.6–82.8 kWh/m2y for Turin and 57.7–60.1 for Palermo). In all cases, energy-optimal solutions result as nearly optimal also from the comfort point of view, which demonstrate the validity of the implemented total energy approach.Beyond the numerical results, we provide an effective integrated methodology that is able to support designers in defining a unique energy and comfort optimized solution to be implemented in the real design analyzing the design space and determining the optimal set of passive solutions to minimize the total energy needs of a building in a context of good comfort conditions, going beyond the Pareto optimality concept and without dealing through complex multi-objective optimization processes.

Re-functioning of Inter-War Modernism Buildings in Kaunas (Lithuania): the Aspect of Users’ Comfort

This study is aimed at analysing the possibilities of contemporary use and re-functioning of Kaunas inter-war modernism buildings from the users’ comfort point of view. For the study, we have selected the building of the House of Commerce, Industry and Crafts designed in 1937 - 1939 by the well-known architect of this period V. Landsbergis-Zemkalnis that was continuously used and re-used for the administrative, office, and library purposes through its entire existence. In the frame of this research the analysis of literature, including the peculiarities of heritage building re-functioning from the users’ comfort point of view and the historical context of the case study building, and the field study including the photographical survey and the measurements of thermal conditions during warm and cold seasons were carried out. The research on site has shown the favourable conditions for the users according to the contemporary standards; however, the deterioration of some building’s structures threaten its heritage values and the use possibilities in the future. It can be concluded that the prestige generated by the heritage values and social significance of Kaunas inter-war modernism architecture together with the appropriate thermal conditions for the users encourage sustainable renovation and re-functioning of such buildings for the needs of contemporary society. DOI: http://dx.doi.org/10.5755/j01.sace.20.3.19323

Parametric Investigation Using Computational Fluid Dynamics of the HVAC Air Distribution in a Railway Vehicle for Representative Weather and Operating Conditions

A computational fluid dynamics (CFD) analysis of air distribution in a representative railway vehicle equipped with a heating, ventilation, air conditioning (HVAC) system is presented in this paper. Air distribution in the passenger’s compartment is a very important factor to regulate temperature and air velocity in order to achieve thermal comfort. A complete CFD model, including the car’s geometry in detail, the passengers, the luminaires, and other the important features related to the HVAC system (air supply inlets, exhaust outlets, convectors, etc.) are developed to investigate eight different typical scenarios for Northern Europe climate conditions. The results, analyzed and discussed in terms of temperature and velocity fields in different sections of the tram, and also in terms of volumetric parameters representative of the whole tram volume, show an adequate behavior from the passengers’ comfort point of view, especially for summer climate conditions.

Pilot randomized controlled trial on early and late remote ischemic preconditioning prior to complex cardiac surgery in young infants.

Remote ischemic preconditioning involves providing a brief ischemia-reperfusion event to a tissue to create subsequent protection from a more severe ischemia-reperfusion event to a different tissue/organ. The few pediatric remote ischemic preconditioning studies in the literature show conflicting results. We conducted a pilot randomized controlled trial to determine the feasibility of conducting a larger trial and to gather provisional data on the effect of early and late remote ischemic preconditioning on outcomes of infants after surgery for congenital heart disease. This single-center, double-blind randomized controlled trial of remote ischemic preconditioning vs control (sham-remote ischemic preconditioning) in young infants going for surgery for congenital heart disease at the Stollery Children's Hospital. Remote ischemic preconditioning was performed at 24-48h preoperatively and immediately prior to cardiopulmonary bypass. Remote ischemic preconditioning stimulus was performed with blood pressure cuffs around the thighs. Primary outcomes were feasibility and peak blood lactate level on day 1 postoperatively. Fifty-two patients were randomized but seven patients became ineligible after randomization leaving 45 patients included in the study. In theincluded patients, 7 (15%) had protocol deviations (five infants did not have the preoperative intervention and two did not receive the intervention in the operating room). From a comfort point of view, only one subject in the control group and two in the Remote ischemic preconditioning group received sedation during the preoperative intervention. There were no study-related adverse events and no complications to the limbs subjected to preconditioning. There were no significant differences between the Remote ischemic preconditioning group and the control group in the highest blood lactate level on day 1 postoperatively (mean difference, 1.28; 95%CI, -0.22, 2.78; P-value=0.093). In infants who underwent surgery for congenital heart disease, our pilot randomized controlled trial on early and late remote ischemic preconditioning proved to be feasible but did not find any significant difference in acute outcomes. A larger trial may be necessary.

Conjugate Heat Transfer Analysis in a Glazed Room Modeled as a Square Cavity

ABSTRACTA numerical study of conjugate heat transfer by turbulent natural convection in a room with three different glazed configurations is presented. The room is modeled as a square closed cavity, where the lower wall is adiabatic, the right wall is semitransparent, and the upper and left walls are opaque conductive surfaces. Governing equations of mass, momentum, and energy were solved by the finite volume method with a two equation turbulence model. The results are presented in terms of streamlines, isotherms, heatlines, turbulent viscosity isolines, and thermal parameters, such as indoor temperatures and heat transfer coefficients. From the three cases considered in this study, the reflective glass window was the optimal configuration from the thermal comfort point of view for both design days. On the contrary, the glass-film configuration showed the worst indoor thermal performance inside the cavity despite of being the configuration that allows lower energy transferred into the room through the glazed surface. A set of useful heat transfer correlations are obtained for building design applications and energy codes in temperate climates.

HVAC automotive vents evaluation and their performance

Car passengers’ comfort is increasingly important, not only from good feelings or travel comfort point of view, but also from the transportation safety perspective, where the driver's thermal comfort is of crucial importance. The main components affecting optimal comfort are HVAC vents. This article focuses on the performance assessment of a side dashboard car vent with adjustable horizontal vanes that allow changing the air jet direction vertically along with a complete shut-off. A new measuring methodology is presented here; it simulates real and complete ventilation system conditions using a simple laboratory piece of equipment with a single vent mounted. The flow pattern as generated by the vent jet was first studied with smoke visualization, then using a two-wire constant-temperature anemometer probe. Jet orientations and boundaries were identified for particular vent settings, which are fundamental in the assessment of vent performance. The average air speed and turbulence intensity were determined. Results show that the actual jet direction differs substantially from the direction that was set by the vanes and that further research may lead to a new and improved design of automatic control of a zonal ventilation system and contribute to more accurate control of passengers’ comfort.

Can diaphragm pacing improve gas exchange? Insights from quadriplegic patients

To the Editor: Diaphragm pacing, as obtained by phrenic nerve stimulation through implanted electrodes, is a valid alternative to positive pressure mechanical ventilation (PPV) in patients with high spinal cord injuries [1]. Diaphragm pacing allows such patients to be weaned from PPV, but, to date, the respective effects of diaphragm pacing and PPV on gas exchange have not been compared. PPV is known to reduce ventilation in the lung bases [2]. By contrast, diaphragm pacing, like spontaneous breathing, should direct a larger proportion of the inspired volume to the lung bases. This should improve ventilation/perfusion matching. If this is the case, diaphragm pacing could be of interest as an adjunct to PPV in patients with lung injury. Indeed, in this setting, preserving diaphragmatic activity during mechanical ventilation can improve arterial oxygenation [3]. However, this can be difficult to achieve from a comfort point of view. In a proof-of-concept perspective, we compared blood gases and energy expenditure during PPV and diaphragm pacing in 10 quadriplegics. 10 consecutive, stable and well-nourished tracheotomised quadriplegic patients were studied (six males, aged 15–46 years, mean±sd body mass index 21.9±4.0 kg·m−2). All had a phrenic nerve stimulator (Atrostim; Atrotech, Tampere, Finland) implanted at least 6 months earlier and were considered fully reconditioned. They were studied during planned routine visits, after approval of the ethics committee of the French Learned Society for Intensive Care Medicine. All patients gave their informed consent. Measurements were performed at least 3 h after a meal, with the tracheal cuff inflated. Oxygen consumption ( V ′O2), carbon dioxide production ( V ′CO2) and respiratory quotient were …

Engineering of cotton fabrics for maximizing in vitro ultraviolet radiation protection

Cotton fabrics used in summer do not often provide good protection against solar ultraviolet (UV) radiation. Heavy cotton fabrics can provide good protection against UV radiation. However, heavy fabrics are not good from a comfort point of view as the air permeability and moisture vapour transmission rate is very low. To engineer cotton fabrics which will provide maximum UV protection without sacrificing the minimum requirement of air permeability and thermal resistance for a particular climatic condition. Sixteen plain and sixteen twill woven fabrics were manufactured using different cotton yarn count and picks per cm. Nonlinear regression models were developed to relate the fabric parameters with the ultraviolet protection factor (UPF), air permeability and thermal resistance. Optimization problems were formulated for UPF maximization keeping air permeability and thermal resistance as constraints. Optimization problems were solved to find out the values of yarn count and picks per cm. New fabrics were then woven using optimized combinations of yarn count and picks per cm, and error assessment between the target and the achieved fabric properties was performed. The target, optimized and achieved fabric properties are showing good association. When air permeability requirement is high, the engineered cotton fabric can provide good UV protection (UPF > 15). When the air permeability requirement is low, the engineered cotton fabric can provide excellent UV protection (UPF > 40). It is possible to engineer cotton fabrics to maximize the UV protection without compromising with the comfort properties.

Ride quality and noise in high speed elevators

Ride quality in an elevator is the latest "hot topic" in elevator design and construction. In skyscrapers being built in Asia, Dubai and the US, the new elevators travel close to and beyond 10m/s. The rides to the highest floors will last well over one minute. From a comfort point of view, it is important that the ride be as smooth and quiet as possible. There are many factors that influence the vibration of the elevator and the concomitant noise. In this paper we will examine the sudden forces that the elevator experiences as it passes each floor. The side forces on the elevator are caused by the asymmetric flow field about the elevator cab. The pressure and streamline flow field was evaluated by using the CFD code FLUENT. Comparison between the numerical and the measured results are given and the pressure disturbances caused by the passage of the elevator and its appendages are discussed together with some solutions to alleviate the pressure disturbances.

Determination of the Overall Heat Transfer Coefficient of the Building Envelope from the Bioclimatic Comfort Point of View

This new method to determine the optimum overall heat transfer coefficients for the opaque components of the building envelope in respect to orientation, window characteristics and transparency ratio, is based on the comfort values of the inner surface temperatures of the facade elements. The inner surface temperatures of the transparent components are calculated initially assuming window characteristics and climatic conditions. The inner surface temperatures for the opaque parts can be calculated from the inner surface temperatures of the transparent components, transparency ratios and the comfort value of the inner surface temperatures of the facade elements. The optimum values of the heat transfer coefficients f or the opaque components are determined from these and the sol-air temperatures.