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1.
A 448 person time field survey of thermal comfort was conducted in rural houses in east Guangdong in 2011-2012, during which the environmental parameters including air tempreture, relative humidity, globe tempreture and air velocity were recorded and the thermal sensation, acceptability and preference of inhabitants were collected. Clothing insulation was found to be a quadratic function of indoor ET*. Thermal sensation was found to be in good linear relationship with air /operation /new effective temperatures, based on which thermal sensation models were established for local inhabitants in rural area. The model shows that the neutral temperature is 26.4℃（ta）, 26.7℃（top）, and 28.5℃（ET*） respectively, and the upper boundary of the 80% acceptable temperature range is 29.0℃（ta）, 29.4℃（top）, and 31.2℃（ET*）in summer respectively. In addition, the preferred temperature in "gray spaces" is higher than that in "absolute spaces" in amount of 0.6℃, indicating that people have lower thermal expectations in gray spaces. Therefore, the architectural features that sets right amount of gray space in traditional architecture should be retained in modern rural residential buildings. 相似文献
2.
Acceptable Temperature Range of Indoor Environment without Air Conditioning and Heating in Hot Summer and Cold Winter Zone 总被引：1，自引：0，他引：1
In order to establish “Evaluation Standard for indoor thermal environment of civil buildings”,acceptable temperature range of indoor environment without air conditioning and heating in hot summer and cold winter zone is indispensable.A two-year field measurement and questionnaire survey were carried on from 2007 to 2009 in Chongqing,which focused on office buildings and residential buildings.After the analysis of indoor and outdoor environment,occupants evaluation and thermal adaptability,a method to obtain the acceptable temperature range,was proposed.Regressing data by temperature range,and combined with human physiological and psychological experiments,the acceptable temperature range of environment without air conditioning and heating in Chongqing was determined according to outdoor air temperature changes in one year.A Comparation of methods to determine the acceptable temperature range in some international standards was discussed. 相似文献
3.
Based on the existing experiment, the heat flux characteristics of green roof in passive indoor thermal environment and thermal parameter suitable for evaluation of the thermal performance of green roof were analyzed. It is found that there is indoor critical temperature in acceptable indoor thermal environment range for green roof, in which there is no heat transfer from roof. Through the correlation analysis of internal surface heat flux of roof and the temperature difference between indoor and outdoor, it is shown that the indoor critical temperature is 1.5℃ lower than air temperature outside for green roof. 相似文献
4.
In this paper, the university teaching buildings in Chongqing are taken as study object, and the indoor thermal environment of classroom is studied with the ways of investigation and testing, in which the indoor thermal environment of classroom is characterized by two aspects: personal and impersonal. The accepted thermal environment range of the classroom in summer is obtained. The difference between predicted thermal sensation and measured one as well as the influence of air velocity on thermal sensation are analyzed. Some measures to improve indoor thermal quality are proposed. 相似文献
5.
Thermal environment in urban public space is considered as an important factor affecting thermal comfort of human beings. In the whole year, thermal environment in public space of the city in hot-summer and cold-winter zone changes dramatically, which has an effect on human thermal comfort. In this study, three typical public spaces including street, park and square of Changsha were selected for a long-term experiment of thermal environment. Based on the analysis of four significant thermal environment parameters-air temperature, relative humidity, global temperature and wind speed, seasonal characteristics of thermal environment in urban public space were obtained. The results show that the characteristics of urban thermal environment are determined by natural climate, while the physical structure of a city has essential impact on the changes of local outdoor thermal environment. Affected by plants (trees) and water (Xiangjiang river) air temperature of the street along the street is much lower, relative humidity is higher and solar radiation is weaker in most of the year. Compared to the street along the river, air temperature of the square is higher and solar radiation is stronger. 相似文献
6.
A physiological and psychological experiment was conducted in summer, 2008 to ascertain the effect of air flow on human thermal comfort in hot summer. The statistics analysis shows that air flow makes physiological index and thermal sensation an obvious drop tendency, which is correlated to the air temperature of indoor environment. The lower the air temperature is, the greater the physiological index and the thermal comfort drop. But when the temperature is up to about 34℃, the air flow almost does not make any change to physiological index while the human sensation is still improved. These results indicate that air flow can improve human thermal comfort to some extent, but the improvement has limits. Higher air temperature, strong wind and long time exposure to wind can lead to uncomfortableness. 相似文献
7.
The uniaxial hot compression test with Gleeble-1500D thermal simulator is performed on AZ31-0.5Sr-1.5Y alloy in the temperature range of 250-450 ℃ and stain rates of 0.01-1 s -1 with the maximum deformation degree of 0.85. The hot deformation behavior and hot workability of the alloy are studied. The constitutive equation and processing map of the alloy are established and studied by optical microstructure observation. The results show that the steady flow stress of AZ31-0.5Sr-1.5Y deforms at elevated temperatures can be described by the hyperbolic sine constitutive equation, and the activation energy is about 186.83 kJ/mol. After analyzing the hot processing map, at the true strain of 0.6, there is one unsafe deformation zone in the deformation temperature range of 250-300 ℃ and the strain rate range of 0.3-1 s -1. The optimal processing parameters obtained in the present work are the temperature range of 300-400 ℃ and strain rates of 0.01-1 s -1. 相似文献
8.
Heat Transfer Characteristics of a New Ceiling Radiant Cooling Panel with Uniform Temperature Distribution in the Surface 总被引：1，自引：0，他引：1
A new ceiling radiant cooling panel(CRCP) with a uniform temperature distribution in the surface was introduced, by analyzing the physical structure and heat transfer mechanism of CRCP. A mathematical model of the radiant heat transfer process was established, through which the cooling capacity of CRCP was calculated using MATLAB. Compared with the results of thermal performance test, the mathematical model was reasonable with a maximum error less than 6%. According to the results of model and experiment, in the constant flow condition, due to the air in the sandwich structure, cooling capacity of CRCP decreases as the temperature drops. Limited by the chilled water temperature, the temperature of CRCP usually is in range of 18~20 ℃. Based on the experimental ,the distribution of relative humidity and the temperature in the room and cold load undertaken by convection and radiation respectively in the room were also studied, aiming at providing some relevant basis for the application of CRCP system. 相似文献
9.
Indoor thermal comfort can be significantly improved by natural ventilation with reasonable architectural design. In order to compare natural ventilation effect, the distribution of velocity field, temperature field and the PMV in different architecture layout and orientation design were analyzed with house types in Best House Type Competition. It was found that indoor natural ventilation effect was obviously improved by means of altering the layout and orientation, where the maximum velocity varied from 0.24m/s to 0.82m/s. And the temperature decreased 0.9℃ and the value of PMV was more approximate to comfort. 相似文献
10.
This paper conducts the experimental study on the natural convection characteristics of cold water near the maximum density in horizontal annulus with the fixed inner radius ri=14 mm and different width l=6~18 mm. The temperature at outer wall is maintained at 0 ℃, and the temperature differences between the inner and outer walls range from 2 to 24 ℃. The results show that the heat transfer coefficient at inner wall increases with the increase of the annulus width. When the temperature difference is bellow 4 ℃ or above 8 ℃, the heat transfer coefficient increases with the increase of the temperature difference. When the temperature difference is between 4 ℃ and 8 ℃, it decreases with the increase of the temperature difference. The formula of heat transfer at inner walls is obtained by using the method of linear regression. 相似文献
11.
Large amounts of high-temperature gases were generated in ironmaking plant and ideal acceptable hood above the heat source was not installed affected by process conditions. At the top of the exhaust hood, dust easily escaped because of thermal plume.Based on the test data of dust composition and size distribution in ironmaking plant, numerical models suitable for high-temperature dust gases were established and key boundary conditions for the gas-solid two-phase flow under high-temperature conditions were determined.The study shows velocity decay of convergence field is sharp at the suction outlet and thermal plume is strong in the exhaust hood. The control method of pressure distribution and the key factor to prevent high-temperature dust escaping are proposed in the exhaust hood. Optimized design and engineering practice of the exhaust hood are given when the suction outlet is on the side after analyzing the flow field resulted from coupling effect of thermal plume and ventilation airflow. 相似文献
12.
The simulation model of hybrid radiant cooling floor and displacement ventilation air conditioning system was built and analyzed by software EnergyPlus. By comparing the simulation results and experimental data, it is shown that the simulated indoor air temperature and cooling capacity provided by radiant floor was ±7% deviated from the experimental data. Based on the model, with the change of supply air parameters or supply water parameters, the cooling capacity provided by radiant floor and displacement ventilation, surface temperature of radiant floor, indoor air average temperature, AUST temperature were obtained. Combined with the indoor thermal comfort model, when indoor thermal comfort index PMV varied between -0.5 and 0.5, the recommended supply air and supply water parameters were obtained to provide reference for engineering design and application. 相似文献
13.
Based on the analysis of defect in oil-paper insulation of transformer, 5 corresponding PD models were made to simulate the actual defects existed in transformers. Aging experiment was carried out at different temperature and test voltage. The developing process of different types of PD was studied and the influence of temperature and voltage on PD in oil-paper insulation, were analyzed. Gray images show differences for different typrs of PD or one type of PD at different precedures. Gray images can be used to recognize PD patterns and discharge stage. The research resalts coutribute for further research on PD pattern recognition and insulation aging of transformer. 相似文献
14.
Microencapsulated paraffin insulation mortar (MPIM) was prepared by using low melting point microencapsulated paraffin (MCP) as phase change material. The phase change temperature, enthalpy, thermal conductivity coefficient and phase change thermal storage properties were tested. The result shows phase change temperature and enthalpy of the MPIM are 33 ℃ and 13.42 J/g, respectively. The thermal conductivity coefficient decreases with the increase in the dosage of silane coupling and binder. The thermal conductivity coefficient decreases with the increase in the dosage of the MCP, and then increases. Compared with blank specimens, the heating rate and cooling rate of the MPIM is definitely lagged, and it has good thermal storage properties. 相似文献
15.
A 33-hour field test of outdoor thermal environment was carried out in a typical teaching building cluster located in the hot and humid zone in summer. From the experiment results of local climate data, air temperature, humidity, wind velocity and wet bulb globe temperature (WBGT) at the pedestrian-level, and the typical ground surface temperature, the main characteristics of summer outdoor thermal environment of teaching building cluster in hot and humid zone are obtained. The results show that the patio, overhead and porous pavement can reduce the pedestrian air temperature and WBGT effectively at summer daytime. And the function of the following design methods to improve the outdoor thermal comfort at the summer daytime has the order like overhead>patio>porous pavement>imporous pavement>concrete road. The WBGT at all measuring points at nighttime are almost the same. The test results are further used to verify the existing mathematical models of outdoor velocity and WBGT. The results show that the relative errors are within 6%. Then, the calculation values are in good agreement with the experimental values. 相似文献
16.
《Medicinal Plant》2014,(1)
[Objective]To investigate the effect of different temperature on the germination of fire hemp seeds,so as to getting the optimal temperature for the germination of fire hemp seeds. [Methods] By setting 10 temperature gradients between 0- 45 ℃ in constant incubators in laboratory,three indicators including the germination vigor,germination rate and germination index were measured and processed by arcsine transformation for significance analysis. [Results]The results showed that fire hemp seeds germinated at the temperature between 5- 35 ℃.The highest germination rate was 95% at 20 ℃; and the germination vigor and germination index of fire hemp seeds reached the peak of92. 3% and 40. 3% at 25 ℃ respectively. The germination rate descended dramatically with the increase or decrease of treatment temperature.Analysis of variance( ANOVA) showed that there was no significant difference in germination vigor and germination rate between 20 and 25℃,but did in germination index. [Conclusions]The temperature suitable for the germination of fire hemp seeds ranges from 5- 35 ℃,with the optimal one of 25 ℃. 相似文献
17.
Numerical simulation on natural convection of water near the maximum density in horizontal annulus
In order to understand the basic characteristics of the heat transfer of natural convection of water near the maximum density in a horizontal annulus, two dimensional numerical simulation was conducted using the finite volume method. The outer wall temperature was maintained at 0 ℃, and the temperature of inner wall at 1 ℃ to 10 ℃. The results show that the heat transfer coefficient at the inner wall first decreases with increased annulus width, then increases, and then constantly decreases with the increased inner radius in the region of calculation. When the temperature difference is below 4 ℃, the heat transfer coefficient increases with increasing temperature difference. When the temperature difference exceeds 4 ℃, it decreases with the increase of the temperature difference. Finally, the formula of heat transfer at the inner wall was obtained by using stepwise linear regression. 相似文献
18.
Xu JingFeng 《保鲜与加工》2005,(3):13-18
With the attention to the comfort degree of living environment, the phenomenon of making use of the PMV -PPD index within the ISO7730 standard to evaluate the indoor thermal comfort degree is more and more widespread. Many papers about indoor thermal environment are based on the PMV - PPD index as the reference or basis to research and analyze. But few people understand and pay attention to the application range of the PMV - PPD index. So some people misuse and abuse the PMV index and deduce some inaccurate conclusions. In this thesis, based on the analysis of the process of deducing PMV equation, the phenomenon that PMV index is different from the fact in the high temperature condition is explained; furthermore the application range of the PMV equation is confirmed. So to obtain the scientific and reasonable evaluation and conclusion in the process of research of the thermal comfort degree can be ensured. 相似文献
19.
The heat conduction characteristic of glass curtain wall was investigated. Based on one dimensional steady heat conduction theory, the numerical calculation model of glass system thermal transmittance was set up by using insulating glass as an example. Based on two dimensional steady heat conduction theory and finite element method, both the thermal transfer matrix and temperature load array of 3 DOFs triangular element were derived. Then the revised formulas about the heat transfer matrix and temperature load array under the boundary conditions of constant heat flux, heat convective, radiation and coupled of them were also derived. Then the numerical calculation models of glass curtain wall frame and linear thermal transmittance were set up. The program TJCW based on the Visual C++ and ObjectARX was developed for calculating the thermal transmittance of glass curtain wall and was validated by contrast with the results calculated by thermal software LBNL. Finally, TJCW program was used to calculate and check the thermal transmittance of glass curtain wall in a practical project. The results indicate that the thermal transmittance of glass curtain wall can be calculated correctly by adopting the presented model, and the program based on this model can be used in energy conservation calculation and analysis in the actual projects. 相似文献
20.
In order to investigate the fire resistance of steel columns with partial fire retardant coating damage in fire, based on the differential equation of equilibrium on each portion of steel column, the deflection of steel column after the fire retardant coating damage was derived, with the pined ends and rigid ends of the columns at elevated temperatures. The critical temperature calculation method was proposed for partial fire protection damage and axial restrained steel columns by taking the edge yielding criteria. The deflection and axial displacement were verified by finite element method at elevated temperature. With a case study, the critical temperature and relationship of axial force and temperature were obtained for pined column with axial restraint. It was shown that the axial force of the steel column at elevated temperatures was increased and the critical temperature was decreased by the axial restraint. The longer the fire retardant coating damage was and the higher the axial restraint was, the lower the critical temperature was. 相似文献