Air Environment and Energy Performance of a Building Courtyard in the Heating Season

2014 ◽  
Vol 501-504 ◽  
pp. 2231-2239
Author(s):  
Ning Bo Zhang ◽  
Yan Ming Kang ◽  
Ke Zhong ◽  
Jia Ping Liu
Keyword(s):  
Air Temperature ◽  
Natural Ventilation ◽  
Environmental Parameters ◽  
Ambient Air ◽  
Energy Performance ◽  
Building Envelope ◽  
Air Infiltration ◽  
Central Air Conditioning ◽  
Pollutant Source ◽  
New Buildings

Courtyards are now used in many new buildings in China for taking advantage of better natural ventilation and thus improving the microclimate. However, when the building is equipped with a central air-conditioning (AC) system for space heating in winter, the warm air infiltration from the heated rooms enters into the courtyard and leads to changes in the natural ventilation characteristics in the courtyard. In the present study, the air environment and energy performance of a courtyard style office building in Shanghai were monitored in winter. The internal and external environmental parameters such as air temperature, CO2and particle concentrations were measured simultaneously and continuously when the building was heated or was not in use. The results show that when there is no apparent pollutant source in the courtyard, a better microenvironment can be established and the air quality in the space is almost the same as the ambient air, because its natural ventilation is enhanced by the warm air infiltration from the heated rooms. Compared to a building without a courtyard, the building envelope heat loss can be reduced by 20% or 11% in winter for buildings with or without a corridor facing the courtyard enclosed by glass windows, respectively, due to the warm air infiltration which increases the air temperature in the courtyard.

Measurement of indoor environmental parameters and analysis of the condensation phenomenon in urban utility tunnels

2022 ◽  
pp. 1420326X2110564
Author(s):  
Chuanmin Tai ◽  
Guansan Tian ◽  
Wenjun Lei
Keyword(s):  
Water Supply ◽  
Surface Temperature ◽  
Air Temperature ◽  
Natural Ventilation ◽  
Environmental Parameters ◽  
Dew Point ◽  
Control Mode ◽  
Safe Management ◽  
Environmental Test ◽  
Water Supply Pipeline

Condensation is a major issue in the safe operation of utility tunnels. To address the condensation problem, the indoor air temperature, relative humidity (RH) and surface temperature in an urban utility tunnel in Jining were continuously measured, and the condensation conditions were surveyed and analysed. The results indicated that under natural ventilation conditions, the air temperature in the comprehensive cabin varied from 23.4°C to 24.5°C, the RH fluctuated between 86.4% and 95.3%, and the corresponding air dew point temperature (DPT) remained in the range of 22.2°C–22.9°C. The surface temperature of the water supply pipeline ranged from 17.8°C to 18.5°C, which was far lower than the DPT in the tunnel, resulting in serious condensation. A water supply pipeline with an anti-condensation design was developed based on environmental test data. A 25-mm-thick rubber plastic sponge insulation layer was used to thermally insulate the water supply pipeline, preventing further dew condensation. Furthermore, mechanical ventilation had little effect on reducing the RH in the tunnel and may actually cause dew condensation; therefore, a ventilation control mode was proposed in this study. These results are expected to provide basic data for further research and reference for the safe management of utility tunnels.

scholarly journals FROM ENERGY STRATEGIES THROUGH ENERGY RETROFITTING TO FIRE SAFETY OF BUILDINGS

2016 ◽  
Author(s):  
Ivana Banjad Pečur ◽  
Borka Bobovec ◽  
Bojan Milovanovic ◽  
Marina Alagušic
Keyword(s):  
Fire Safety ◽  
Heat Exposure ◽  
Energy Performance ◽  
Building Envelope ◽  
Test Method ◽  
European Policy ◽  
Fire Load ◽  
National Test ◽  
New Buildings ◽  
Energy Strategies

European policy is reflected in a 10-year strategy called 2020 proposed to revive European economy and it is deeply interconnected with Energy Performance of Building Directive and its Recast. Republic of Croatia, as an EU member state, is aligning its national energy policy with European policy. By boosting energy retrofitting of existing and constructing energy efficient new buildings, thermally enhanced building envelope represents significantly increased fire load on building, thus fire safety becomes inevitable segment of energy efficiency of buildings. Croatia has no national test method for determining fire performance of building façade, while harmonized EN test method is currently being developed. In this paper an overview and comparison of BS 8414-1:2002 and DIN Entwurf 4102-20 standards will be presented, since they are proposed as a basis for future harmonized EN test method. For similar configuration of test specimens, BS 8414-1:2002 defines significantly more severe heat exposure compared to DIN Entwurf 4102-20.

Applicable Correlations Based on Field Survey and Theory for Predicting the Indoor Thermal Climate

2012 ◽  
Vol 610-613 ◽  
pp. 2819-2822
Author(s):  
Fen E Hu ◽  
Fan Wang ◽  
Neng Bang Hou ◽  
Fei Xiang Chen
Keyword(s):  
Solar Radiation ◽  
Air Temperature ◽  
Natural Ventilation ◽  
Thermal Sensation ◽  
Environmental Parameters ◽  
Newton’S Iterative Method ◽  
Diffuse Solar Radiation ◽  
Thermal Climate ◽  
One Year ◽  
Radiant Temperature

Fanger’s PMV is the most famous thermal sensation index but it is too complex to be applied in practice. Besides, the PMV index does not take into account the effect of the hourly beam and diffuse solar radiation absorbed by the room on the indoor thermal climate. In order to obtain applicable correlations with consideration of solar radiation, a one-year measurement has been carried out in a naturally ventilated residential room in Qujing Normal University of Yunnan province, China. Based on collected data, PMV indices are calculated by using Newton’s iterative method. The correlations of the PMV and the environmental parameters — outdoor air temperature, indoor mean air temperature, mean radiant temperature, wind velocity, relative humidity, and hourly beam and diffuse solar radiation — have been studied by using the multivariable regression techniques. Lots of correlations with high correlativity have been developed in this paper. It is convenient to use these results to predict the indoor thermal climate in the natural ventilation buildings in the subtropical plateau monsoon climate.

scholarly journals Evaluation of in-situ cooling performance at renovation 2050: comparing zone vs. central based cooling systems for single family dwellings

2021 ◽  
Author(s):  
Anthony Guadagnoli
Keyword(s):  
Relative Humidity ◽  
Energy Use ◽  
Energy Performance ◽  
Building Envelope ◽  
Single Family ◽  
Energy Usage ◽  
Central System ◽  
Cooling Performance ◽  
Central Air Conditioning ◽  
Air Conditioning Systems

The objective of this Major Research Project has been to compare the benefits of cooling performance of zoned and central air conditioning systems using summer 2013 as an evaluation period. Three adjacent houses in Toronto have been studied as part of the Renovation2050 research program. Total cooling energy usage was measured directly from all cooling equipment, along with temperature and cooling energy usage was measured directly from all cooling equipment, along with temperature and relative humidity readings via remote sensors. The goal of this 1-year study was to compare the cooling energy performance of each house, temperature, and relative humidity. The study has used energy simulation, to compare zoned and central systems while accounting for weather, human occupancy, and construction types. Results have shown that there is potential for energy benefits on a zoned system compared to a central system by approximately 95% in total cooling energy use for the study period,and these results are dependent on the building envelope and user types and these results are dependent on the building envelope and user types.

scholarly journals The Influence of Isotropic Surface Roughness of Steel Sliders on Ice Friction Under Different Testing Conditions

Lubricants ◽  
2019 ◽  
Vol 7 (12) ◽  
pp. 106
Author(s):  
Velkavrh ◽  
Lungevičs ◽  
Jansons ◽  
Klien ◽  
Voyer ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Air Temperature ◽  
Normal Load ◽  
Environmental Parameters ◽  
Ambient Air ◽  
Sliding Velocity ◽  
Ice Surface ◽  
Ice Friction ◽  
The Coefficient Of Friction ◽  
Ice Surface Temperature

Ice friction is affected by various system and surface-related parameters such as ice temperature, ambient air temperature and humidity, relative sliding velocity, specific surface pressures and surface texture (waviness, roughness) as well as the macroscopic geometry of the samples. The influences of these parameters cannot be easily separated from each other. Therefore, ice friction is a very complex tribological system and it is challenging to draw sound conclusions from the experiments. In this work, ice friction experiments with stainless steel samples that have different isotropic surface roughness values were carried out. Two tribological experimental setups were used: (i) an inclined ice track where the sliding velocity of the freely sliding steel samples was determined and (ii) an oscillating tribometer, where the coefficient of friction was assessed. For both experimental setups, the environmental parameters such as air temperature, relative humidity and ice surface temperature as well as the test parameters such as normal load and surface pressure were kept as constant as possible. The results of the experiments are discussed in relation to the ice friction mechanisms and the friction regimes.

scholarly journals Energy performance analysis of GE-F5 gas turbines at off-design conditions by applying an innovative convergent–divergent system for the inlet air cooling

2019 ◽  
Vol 52 (9-10) ◽  
pp. 1508-1516
Author(s):  
Seyed Mehdi Arabi ◽  
Hossein Ghadamian ◽  
Mohammad Aminy ◽  
Hassan Ali Ozgoli ◽  
Behzad Ahmadi ◽  
...  
Keyword(s):  
Output Power ◽  
Air Temperature ◽  
Gas Turbines ◽  
Power Plants ◽  
Characteristic Curve ◽  
Ambient Air ◽  
Energy Performance ◽  
Air Cooling ◽  
Design Algorithm ◽  
Ambient Air Temperature

Ambient air temperature increase, in a gas power plant, causes the intake air mass flow rate to be decreased and can have a significant reducing effect on output power and efficiency. To compensate for this reduction, at different climate conditions, various systems can be used to cool the inlet air. To predict the performance of a gas turbine at off-design conditions (by changing surrounding conditions and/or the air cooling method), modeling of the unit performance is required. Due to the high consumption of water and electricity in the conventional cooling systems, in this paper, in addition to introducing an off-design algorithm, governing equations of each cycle elements were inferenced by their characteristic curve. By developing code in MATLAB software, the effect of applying a novel convergent–divergent system on GE-F5 gas units in Yazd Zanbagh power plants was studied. The results show that in a temperature range between 14 and 50 °C, for each degree decrease in ambient air temperature, an approximately 8.99 kW increase in output power can be obtained. The main advantage of this system is the capability of its application in both dry and humid regions. In addition, the refrigerant medium is not required, which makes this system desirable to use in arid areas.

New Correlations Including Hourly Horizontal Radiation for Predicting Indoor Thermal Environment

2011 ◽  
Vol 71-78 ◽  
pp. 2671-2674
Author(s):  
Sheng Xian Wei ◽  
Shi Mei Guo ◽  
Xi Jia He
Keyword(s):  
Solar Radiation ◽  
Air Temperature ◽  
Natural Ventilation ◽  
Thermal Environment ◽  
Thermal Sensation ◽  
Environmental Parameters ◽  
Newton’S Iterative Method ◽  
Indoor Thermal Environment ◽  
One Year ◽  
Radiant Temperature

Fanger’s PMV is the most famous thermal sensation index but it is too complex to be applied in practice. Besides, the PMV index does not include the effect of horizontal solar radiation on the indoor thermal environment. In order to obtain simple and applicable correlations with consideration of solar radiation, a one-year measurement has been conducted in a naturally ventilated residential room in Qujing Normal University of Yunnan province, China. Based on collected data, PMV indices are calculated by using Newton’s iterative method. The relationships of the PMV and the environmental parameters — outdoor air temperature, indoor mean air temperature, mean radiant temperature, wind velocity, relative humidity, and hourly horizontal solar radiation — have been studied by the multivariable regression techniques. Large numbers of correlations with high correlativity have been developed in the present paper. It is convenient to use them to evaluate and predict the indoor thermal environment in the natural ventilation buildings.

scholarly journals Evaluation of in-situ cooling performance at renovation 2050: comparing zone vs. central based cooling systems for single family dwellings

2021 ◽  
Author(s):  
Anthony Guadagnoli
Keyword(s):  
Relative Humidity ◽  
Energy Use ◽  
Energy Performance ◽  
Building Envelope ◽  
Single Family ◽  
Energy Usage ◽  
Central System ◽  
Cooling Performance ◽  
Central Air Conditioning ◽  
Air Conditioning Systems

The objective of this Major Research Project has been to compare the benefits of cooling performance of zoned and central air conditioning systems using summer 2013 as an evaluation period. Three adjacent houses in Toronto have been studied as part of the Renovation2050 research program. Total cooling energy usage was measured directly from all cooling equipment, along with temperature and cooling energy usage was measured directly from all cooling equipment, along with temperature and relative humidity readings via remote sensors. The goal of this 1-year study was to compare the cooling energy performance of each house, temperature, and relative humidity. The study has used energy simulation, to compare zoned and central systems while accounting for weather, human occupancy, and construction types. Results have shown that there is potential for energy benefits on a zoned system compared to a central system by approximately 95% in total cooling energy use for the study period,and these results are dependent on the building envelope and user types and these results are dependent on the building envelope and user types.

scholarly journals AWARENESS OF THE EQUILIBRIUM MOISTURE CONTENT OF CHIA SEEDS IS AN IMPORTANT STEP TO PRESERVING IT

2020 ◽  
Vol 20 (1) ◽  
pp. 12-16
Author(s):  
L. Ovsiannykova ◽  
O. Sokolovskaya ◽  
L. Valevskaya ◽  
S. Orlova
Keyword(s):  
Relative Humidity ◽  
Air Temperature ◽  
Practical Importance ◽  
Environmental Parameters ◽  
Nutrient Content ◽  
Ambient Air ◽  
Main Task ◽  
Hygroscopic Properties ◽  
Grain Moisture

The article presents the results of studies of hygroscopic properties of chia seeds, which is a relatively new culturefor the Ukrainian industry. Chia seeds are a product with a high nutrient content and rich in trace elements, vitamins andminerals that can be of great benefit to human health. Therefore, the main task of post-harvest technology is to bring it to a state that will ensure long-term storage of chia seeds without loss in weight and poor quality. An important influence on the condition of the grain mass during storage and, in particular, during the initial treatment has its hygroscopicity, ie the ability to sorption and desorption of water vapor. Knowledge about the hygroscopic properties of grain are of practical importance for the scientific substantiation of the choice of rational modes of active ventilation, drying. The main characteristic of hygroscopic properties of grain materials is equilibrium moisture, so its determination is an important step for maintaining the quality of grain. The equilibrium moisture of chia seeds has been determined for the first time. The studies were carried out by the generally accepted tensimetric method in the range of air temperatures in the range of 5... 25 °C and iota relative humidity of 33...70 %, which model the conditions of storage of seeds and corresponding to the long-term average data, correspond to the warm and cold seasons in Odessa region. The influence of relative humidity, air temperature and grain moisture on the equilibrium moisture of chia was investigated, numerical values of equilibrium moisture of chia seeds were determined according to environmental parameters: temperature 5, 15, 25 °C and relative humidity 33, 45 and 70 %.The nature of the change in the equilibrium moisture of chia seeds was determined depending on the temperature and relative humidity. With increasing relative humidity and decreasing ambient temperature, the equilibrium moisture of chia seeds increases. The empirical coefficients and the equation that describes the dependence of the equilibrium moisture of chia seeds on the parameters of ambient air - temperature and relative humidity at which its change can be predicted.The data obtained can be used to select drying and active ventilation modes, as well as storage conditions for chia.

scholarly journals Evaluation and use of airspaces for thermal resistance in buildings

2021 ◽  
Vol 2069 (1) ◽  
pp. 012098
Author(s):  
H H Saber ◽  
D W Yarbrough
Keyword(s):  
Thermal Resistance ◽  
Flow Direction ◽  
Energy Performance ◽  
Building Envelope ◽  
Surface Radiation ◽  
Air Infiltration ◽  
Aspect Ratios ◽  
Heat Flow Direction ◽  
R Value ◽  
Bounding Surfaces

Abstract The thermal resistance (R-value) of airspaces depends on the emittance of surfaces around the airspace, dimensions, heat-flow direction, and the temperatures of bounding surfaces. Assessing the energy performance of building envelope components and fenestration systems requires accurate results for the R-values of any enclosed spaces. The evaluation of reflective insulation R-values has evolved to include use of computational fluid dynamics and surface-to-surface radiation to quantify convective and radiation contributions to the heat transfer across airspaces of all types. This paper compares an advanced and validated computational tool for calculating enclosed airspace R-values with the widely-used ISO 6946 and airspace R-values in the ASHRAE Handbook-Fundamentals. The tool evaluates construction defects, air-infiltration impact, and dimensional aspect ratios that 1-D methods do not address. The differences between the methods that are currently being used to evaluate the R-value and the advantages of the advanced method for evaluation of reflective insulation applications are discussed.

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