Discomfort Degree Research Articles

Achieving natural ventilation potential in practice: Control schemes and levels of automation

A major challenge to fully achieve the natural ventilation (NV) potential in green buildings is the control and coordination of windows and the HVAC system. Three main types of control schemes with increasing levels of automation were examined in this study: spontaneous occupant control driven by thermal comfort, informed occupant manual control that follows instructional signals, and the fully automatic window/HVAC control system governed by either rule-based heuristic control criteria or a computational backend for model predictive control (MPC). Energy saving performance, indoor thermal comfort, and frequency of operation were used as metrics to evaluate various control schemes. We assessed the effectiveness of these control schemes using five representative climates in China that range from hot to severely cold. Our results demonstrated the advantage of fully automatic system, especially integrated with MPC, which showed energy savings of 17–80% with zero discomfort degree hours. In contrast with MPC, the fully automatic system with heuristic control showed 10–66% energy savings and the same discomfort degree hours. Neither the informed nor the spontaneous occupant control cases studied were able to maintain the indoor air temperature within the comfort range at all times. The informed occupant control in particular resulted in thousands of discomfort degree hours in the worst cases. The spontaneous occupant control showed moderate to no energy savings, whereas the informed occupant control introduced excessive energy usage in certain cases. Overall, the fully automatic NV control system exhibited the best energy saving performance and occupant satisfaction among studied control schemes despite of the additional initial investment. It is particularly true in climates where NV control has a considerable impact on building energy performance and employing improper NV control can cause energy waste and excessive thermal discomfort. In the selection of natural ventilation control system, our analysis suggests that developers and building owners should not only consider the initial system investment and maintenance cost, but also take into account the annual energy savings and occupant satisfaction to fully realize natural ventilation potential.

Development of Building Thermal Load and Discomfort Degree Hour Prediction Models Using Data Mining Approaches

Thermal load and indoor comfort level are two important building performance indicators, rapid predictions of which can help significantly reduce the computation time during design optimization. In this paper, a three-step approach is used to develop and evaluate prediction models. Firstly, the Latin Hypercube Sampling Method (LHSM) is used to generate a representative 19-dimensional design database and DesignBuilder is then used to obtain the thermal load and discomfort degree hours through simulation. Secondly, samples from the database are used to develop and validate seven prediction models, using data mining approaches including multilinear regression (MLR), chi-square automatic interaction detector (CHAID), exhaustive CHAID (ECHAID), back-propagation neural network (BPNN), radial basis function network (RBFN), classification and regression trees (CART), and support vector machines (SVM). It is found that the MLR and BPNN models outperform the others in the prediction of thermal load with average absolute error of less than 1.19%, and the BPNN model is the best at predicting discomfort degree hour with 0.62% average absolute error. Finally, two hybrid models—MLR (MLR + BPNN) and MLR-BPNN—are developed. The MLR-BPNN models are found to be the best prediction models, with average absolute error of 0.82% in thermal load and 0.59% in discomfort degree hour.

Optimal control of HVAC and window systems for natural ventilation through reinforcement learning

Natural ventilation is a green building strategy that improves building energy efficiency, indoor thermal environment, and air quality. However, in practice, it is not always clear when and how to utilize the natural ventilation and coordinate its operation with the HVAC system. This paper introduces a reinforcement learning control strategy, specifically through model-free Q-learning, that makes optimal control decisions for HVAC and window systems to minimize both energy consumption and thermal discomfort. This control system evaluates the outdoor and indoor environments (temperature, humidity, solar radiation, and wind speed) at each time step, and responds with the best control decision that targets both immediate and long-term goals. The reinforcement learning control is evaluated through numerical simulation on a building thermal model and compared with a rule-based heuristic control strategy. Case studies in hot-and-humid Miami and warm-and-mild Los Angeles demonstrated the superior performance of reinforcement learning control, which led to 13% and 23% lower HVAC system energy consumption, 62% and 80% lower discomfort degree hours, and 63% and 77% fewer high humidity hours compared to heuristic control. Unlike heuristic control that requires specific knowledge of individual buildings and the creation of exhaustive decision-making scenarios to improve performance, reinforcement learning control guarantees optimality through self-advancement on given goals and cost functions and is able to adapt to stochastic occupancy and occupant behaviors, which is difficult to accommodate by heuristic control.

Design Optimization Considering Variable Thermal Mass, Insulation, Absorptance of Solar Radiation, and Glazing Ratio Using a Prediction Model and Genetic Algorithm

This paper presents the optimization of building envelope design to minimize thermal load and improve thermal comfort for a two-star green building in Wuhan, China. The thermal load of the building before optimization is 36% lower than a typical energy-efficient building of the same size. A total of 19 continuous design variables, including different concrete thicknesses, insulation thicknesses, absorbance of solar radiation for each exterior wall/roof and different window-to-wall ratios for each façade, are considered for optimization. The thermal load and annual discomfort degree hours are selected as the objective functions for optimization. Two prediction models, multi-linear regression (MLR) model and an artificial neural network (ANN) model, are developed to predict the building thermal performance and adopted as fitness functions for a multi-objective genetic algorithm (GA) to find the optimal design solutions. As compared to the original design, the optimal design generated by the MLRGA approach helps to reduce the thermal load and discomfort level by 18.2% and 22.4%, while the reductions are 17.0% and 22.2% respectively, using the ANNGA approach. Finally, four objective functions using cooling load, heating load, summer discomfort degree hours, and winter discomfort degree hours for optimization are conducted, but the results are no better than the two-objective-function optimization approach.

Thermal performance evaluation of a mineral-based cement tile as roofing material

In tropical climates like India, solar radiation is the major source of heat gain through roofs as they are exposed to the sun throughout the day. As the ambient conditions are dynamic, it is important to look at periodic variation of heat flow through roofs. In this context, apart from U-values that the Energy Conservation Building Code of India (ECBC-2007) prescribes for envelopes, more specific performance indicators should be considered for designing energy efficient buildings. The study presented in this paper evaluates thermal performance of Cement Tile as roofing material and compares it with the performance of two other typical roof insulation materials monitored in hot and dry climate of India. The results are supported with physical structures using Scanning Electron Microscope (SEM) images and energy simulations. Despite having higher overall U-value (over six times), Model 1 (with Cement Tile) shows better thermal performance and negligible energy savings than Model 2 (with extruded polystyrene as insulation material) and Model 3 (with POP false ceiling). Therefore, the overall U-values calculated from the layer wise thermal conductivity along with Discomfort Degree Hour, Building Index, and Average heat flux would provide a better understanding of thermal performance of the roof as was demonstrated by our experiments.

Does immobilization position after arthroscopic rotator cuff repair impact work quality or comfort?

The purpose of this study was to quantify subjective discomfort and decrease in working performance in patients submitted to arthroscopic rotator cuff repair. We enrolled 101 asymptomatic administrative employees (mean age 55). Subjects were asked to write a text using Microsoft Word and to make a table using Microsoft Excel, with and without shoulder braces which kept the right shoulder in neutral (brace A) and internal rotation (brace B). Total time needed to complete the tests and number of mistakes committed were annotated. Furthermore, a questionnaire to assess the subjective and interpersonal discomfort caused by the braces was compiled. Data were submitted to statistical analysis. When any brace is worn, both times and mistakes are higher than those registered without brace (p<0.02). Both times and mistakes are higher for brace B in comparison with brace A (p<0.02). Subjects wearing brace B had a severe/very severe discomfort degree three times higher than that registered in subjects wearing brace A. Finally, 91% of subjects preferred brace A to brace B. If the choice of the brace is not supported by biological or clinical advantages, we recommend to use the brace that keeps the arm at the side, since it ensures better working performance and lower discomfort. It also received the greatest satisfaction of the respondents. IV.

Raman spectroscopy: a tool for biomechanical characterization of Stratum Corneum

The mechanical properties of the Stratum Corneum (SC) have been studied by different authors at the macroscopic level, but the modification of its ultra structure during mechanical extension remains unknown. Moreover, little is described about the effect of the mechanical stress on SC barrier function. In this study, we have examined the SC structure changes, at the molecular level, during uniaxial tensile experiments. This was performed on isolated SC samples using Raman spectroscopy. We could identify the strain status of the analyzed samples by using combination of Raman spectra and Partial Least Squares processing. In addition, this approach provided information about lipids and proteins behavior during the sample extension. The structure of the intercellular lipids bilayer became less organized up to ~9% deformation. For higher strains, a plateau corresponding to the minimum organization is observed till the complete failure of the sample. In the same time, protein structures including desmosomes, were characterized by monotonic secondary structure modifications for deformations up to ~9% followed by a plateau. These observations are relevantly demonstrating the effect of extension on the skin barrier state. Such an approach could be objectively used for clinical applications to evaluate skin discomfort degree and skin elastic behavior. This could therefore help with proof of efficacy for cosmetic and dermatologic products. Copyright © 2013 John Wiley &amp; Sons, Ltd.

Envelope wall/roof thermal performance parameters for non air-conditioned buildings

Many parameters have been used to evaluate the thermal performance of envelope wall/roofs, most of them for air-conditioned buildings. In this paper, the interest is focused on parameters to assess the thermal performance of envelope wall/roofs for non air-conditioned buildings. Five groups of parameters, some previously used and some newly proposed, have been analyzed. To test the evaluation parameters, numerical simulations of the periodic heat transfer through five different roof configurations have been carried out. This research shows the suitability of the energy transferred through the wall/roof during a day, the decrement factor, the discomfort degree hours, and the hot (or cold) thermal performance index to be used for thermal evaluation of wall/roofs in non air-conditioned buildings. The sensitivity of these parameters with climatic conditions and with the outdoor surface solar absorptance is analyzed. Additionally, it has been shown that the steady-state thermal transmittance, the thermal admittance modulus, the periodic thermal transmittance modulus, and the surface decrement factor, calculated with surface temperatures, are not suitable parameters to evaluate wall/roofs in non air-conditioned buildings.

Comparison of skin prick test and skin press test in detecting allergen

Objective To observe the tolerance and positive reaction of skin prick test and skin press test in patients with anaphylactic disease. Methods 80 cases of patients with allergic asthma, rhinitis and other anaphylactic disease were tested by the two tests with specific allergens simultaneously and patients discomfort and scare degree was evaluated, the detection results of specific allergens by the two tests were al-so compared.The results underwent statistical description andχ2 test. Results The difference of the posi-tive rates of allergens between two tests had no significance.Most patients were willing to accept skin press test. Conclusions The results of two tests were similar. But patients receiving skin press test suffer little pain and less fear and are easy to accept the test. So skin press test can substitute for skin prick test in clinical practice. Key words: Allergen; Skin prick test; Skin press test

Clinical study about the effect of modified mi-type elastic bandage on hemostasis of puncture point of radial artery

Objective To compare the effect of hemostasis of puncture point of radial artery be-tween using modified mi- type elastic bandage and TR- Band tourniquet after the operation of coronary in-tervention. Methods 142 patients who were to undergo transradial coronary intervention were divided in-to the observation group (73 cases)and the control group(69 cases). The observation group applied modi-fied mi- type elastic bandage and the control group adopted TR- Band tourniquet. The effect of hemostasis, discomfort degree and incidence rate of local complication were observed in the two groups. Results The success rate of hemostasis of the observation group (98.63%) was higher than that of the control group (94.20%), but the difference between two groups was of no statistical significance. For the discomfort de-gree: the feeling of pain was higher in the control group, incidence of swelling was higher in the observa-tion group,the difference between the two groups had statistical significance,for the incidence of numb-hess,the test was of no statistical significance,for the local skin complication,the difference between two groups was of no statistical significance. Conclusions Putting modified mi- type elastic bandage into the application after the operation of coronary intervention,we find that choosing material is convenient,it is easy to observe and operate,the effect of hemostasis is safe and reliable,the rate of complication is low. So it is one safe, effective and ecnomical hemostasia method. Key words: Modified mi- type elastic bandage; Coronary artery intervention; Radial artery; Hemostasis; Nursing

Studies of the Thermal Environment in Enclosures Exposed on a Single Side: A Case Study in Northern India

Simulation study of thermal performance of enclosures located at Roorkee, India, on a typical peak summer day with exposure on one side, revealed that the indoor environmental temperature in rooms having an exposed roof with low reflectivity remains above the outdoor air temperature throughout the day. Provision of a heat reflecting coating on walls enhancing their reflectivity from normal value of 0.5 to 0.7 does not result in any significant benefit in respect of reduction in indoor environmental temperature. However application of these coatings on the roof helps bring down the indoor environmental temperature during daytime. In rooms with a fully shaded roof, the indoor environmental temperature is reduced by about 1°C and duration of the excessive indoor environmental temperature is being lower than the respective outside air temperature is also enhanced. Shading of the roof reduces the discomfort degree hours significantly. The provision of night ventilation contributes towards amelioration of the indoor thermal environment during late night hours but the benefit accruable on the following day is insignificant compared to the reduction in indoor environmental temperature produced due to application of heat reflecting coatings on the exposed surface or shading of the roof.

Thermal simulation of roof surface evaporative cooling system for India using “TRNSYS”

SYNOPSIS Cooling of buildings by employing evaporation of water is a well-recognised concept for the reduction of mechanical cooling loads of buildings, especially in hot and dry climates. Evaporation of water may be used directly inside the building, as in desert coolers which are quite commonly used in tropical countries; this results in reduction of air temperature and increase in humidity of the indoor air. Alternatively, the exposed surface of the roof may be treated with water producing a cooling effect on the inside air without any increase in humidity. The latter method, referred to as roof surface evaporation cooling (RSEC) technique, has been practiced for a long time now, and has been established as an effective passive cooling technique. This paper presents results of a computer simulation carried out using “TRNSYS” for a single zone building treated with a roof surface evaporative cooling system corresponding to five locations in India representing different climatic conditions. The results of the simulation are analysed in terms of performance parameters, namely, discomfort degree hours (DDH) for a conditioned building and monthly cooling load for a conditioned building. Various walls/roof configurations having different U-values have been considered and calculations have been made corresponding to different set-point temperatures (25°C to 30°C) for indoor temperature. It is observed that a reduction in number of DDH and cooling load could be substantial for hot & dry and composite climatic zones, though less effective for warm & humid climates. The effectiveness of the RSEC system as a function of difference in roof composition and External Shade Factor of windows has also been presented.

Efficacy of intrarectal lidocaine hydrochloride gel for pain control in patients undergoing transrectal prostate biopsy

To determine the efficacy of intrarectal lidocaine hydrochloride gel in reducing pain in patients undergoing transrectal prostate biopsy. During the period from June to November 2002, 72 patients undergoing transrectal prostate biopsy at an outpatient service were prospectively randomized. Patients were divided into 2 groups. In group 1, 20 mL of 2% lidocaine gel were administered by intrarectal route 15 minutes before biopsy. In group 2 (placebo), 20 mL of ultrasound gel were administered under the same conditions. At the end of the procedure, patients were asked to classify the discomfort degree observed during the procedure through a verbal pain scale. Statistical analysis was performed through qui-square test. The majority of patients in both groups presented slight pain on the examination, and 26 patients (76.4%) from group 1, and 26 (68.3%) patients from group 2 reported slight pain or no pain at all (p > 0.05). Moderate or intense pain was felt by 23.4% of patients in group 1 and 31.5% of patients in group 2 (p > 0.05). We concluded that lidocaine probably exerts a minimal effect on patients' tolerance to pain on transrectal prostate biopsy.

Competência social na formação do psicólogo

O objetivo deste estudo foi avaliar dimensões do repertório de competência social de alunos de início e término do curso de Psicologia e verificar se eventuais deficits são acentuados ou superados ao longo da formação acadêmica. Aplicou-se um questionário com 13 situações críticas de interação social em relação às quais o aluno deveria indicar: o grau de incidência da situação em sua experiência, o grau de incomodo produzido, a emissão (ou não) da resposta indicadora de competência social sugerida para a situação e a satisfação ou insatisfação com a resposta emitida. Os resultados evidenciaram um padrão amplo de semelhanças e bastante restrito de diferenças entre alunos de início e término do curso em todas as dimensões, exceto na de incômodo, com implicações para outras pesquisas.