建筑環(huán)境與設(shè)備工程(暖通)外文翻譯---未來的熱舒適性——優(yōu)越性和期望值(編輯修改稿)
2025-02-14 00:17 本頁(yè)面
【文章內(nèi)容簡(jiǎn)介】 may be to , while it may be to where there are many airconditioned buildings. In regions with only brief periods of warm weather during the summer, the expectancy factor may be to 1. Table 1 proposes a first rough estimation of ranges for the expectancy factor corresponding to high, moderate and low degrees of expectation.ExpectationClassification of buildingsExpectancyfactor, eHighNonairconditioned buildings located in regions where airconditioned buildings are mon. Warm periods occurring briefly during the summer season. ModerateNonairconditioned buildings located in regions with some airconditioned buildings. Warm summer season. LowNonairconditioned buildings located in regions with few airconditioned buildings. Warm weather during all seasons. Table 1. Expectancy factors for nonairconditioned buildings in warm climates.A second factor that contributes to the difference between the PMV and actual thermal sensation in nonairconditioned buildings is the estimated activity. In many field studies in offices, the metabolic rate is estimated on the basis of a questionnaire identifying the percentage of time the person was sedentary, standing, or walking. This mechanistic approach does not acknowledge the fact that people, when feeling warm, unconsciously tend to slow down their activity. They adapt to the warm environment by decreasing their metabolic rate. The lower pace in warm environments should be acknowledged by inserting a reduced metabolic rate when calculating the PMV.To examine these hypotheses further, data were downloaded from the database of thermal fort field experiments. Only quality class II data obtained in nonairconditioned buildings during the summer period in warm climates were used in the analysis. Data from four cities (Bangkok, Brisbane, Athens, and Singapore) were included, representing a total of more than 3200 sets of observations . The data from these four cities with warm climates were also used for the development of the adaptive model.For each set of observations, recorded metabolic rates were reduced by % for every scale unit of PMV above neutral, . a PMV of corresponded to a reduction in the metabolic rate of 10%. Next, the PMV was recalculated with reduced metabolic rates using ASHRAE’s thermal fort tool . The resulting PMV values were then adjusted for expectation by multiplication with expectancy factors estimated to be for Brisbane, for Athens and Singapore and for Bangkok. As an average for each building included in the field studies, Figure 1 and Table 2 pare the observed thermal sensation with predictions using the new extended PMV model for warm climates.Comparison of observed mean thermal sensation with predictions made using the new extension of the PMV model for nonairconditioned buildings in warm climates. The lines are based on linear regression analysis weighted according to the number of responses obtained in each building.CityExpectancyfactorPMV adjusted toproper activityPMV adjustedfor expectationObservedmean voteBangkokSingaporeAthensBrisbaneTable 2. Nonairconditioned buildings in warm climates. Comparison of observed thermal sensation votes and predictions made using the new extension of the PMV model.The new extension of the PMV model for nonairconditioned buildings in warm climates predicts the actual votes well. The extension bines the best of the PMV and the adaptive model. It acknowledges the importance of expectations already accounted for by the adaptive model, while maintaining the PMV model’s classical thermal parameters that have direct impact on the human heat balance. It should also be noted that the new PMV extension predicts a higher upper temperature limit when the expectancy factor is low. People with low expectations are ready to accept a warmer indoor environment. This agrees well with the observations behind the adaptive model.Further analysis would be useful to refine the extension of the PMV model, and additional studies in nonairconditioned buildings in warm climates in different parts of the world would be useful to further clarify expectation and acceptability among occupants. It would also be useful to study the impact of warm office environments on work pace and metabolic rate.ConclusionsThe PMV model has been validated in the field in buildings with HVAC systems, situated in cold, temperate and warm climates and studied during both summer and winter. In nonairconditioned buildings in warm climates, occupants may perceive the warmth as being less severe than the PMV predicts, due to low expectations.An extension of the PMV model that includes an expectancy factor is proposed for us
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