Variation of biological and hydrological parameters and nitrogen removal optimization of modified Carrousel oxidation ditch process

To enhance the nitrogen removal,a systemic monitoring of the biological and hydrological parameters of Carrousel oxidation ditch in Chongqing Jingkou Wastewater Treatment Plant was carried out to study the feasibility of simultaneous nitrification and denitrification(SND).The variation and distribution of parameters such as flow velocity,concentration of dissolved oxygen(DO) and mixed liquor suspended solids(MLSS) in oxidation ditch were monitored and analyzed,which were major control factors for SND.The results showed that,the dimensional distribution of flow velocity,DO and MLSS were affected significantly by the operation condition of the aeration wheels.With all the four aeration wheels being in operation,DO and flow velocity were higher and the mixing of MLSS was sufficient.With three aeration wheels being in operation,the flow velocity in most of the bottom areas was enough to meet the basic requirements of no deposition,and the anaerobic region and aerobic region could exist simultaneously in one oxidation ditch,which was helpful to the process of SND.According to spatial distribution characteristics of the flow velocity,DO and soluble components under optimized condition,different functional zones of biochemical reaction in the Carrousel oxidation ditch system were defined,which might contribute to the optimization control and SND of Carrousel oxidation ditch.

Impact of cold indoor thermal environmental conditions on human thermal response

To explore the thermal responses under the non-thermal equilibrium cold environmental conditions,a laboratory study was conducted in climate chamber.The local skin temperatures and thermal sensation of 20 subjects were recorded at 10 min intervals for 90 min under air temperatures of 7.4,9.1,11 and 15 °C.The results show that both local skin temperatures and mean skin temperature decrease not only with the drop of ambient air temperature but also with the exposure time.Local thermal sensation and overall the thermal sensation have the similar temperature-varying and time-varying characteristics.Predicted mean vote(PMV) model cannot correctly predict the thermal sensation under non-thermal equilibrium cold environment.The correlation between local thermal sensation and local skin temperatures shows that thermal sensation is closely related to skin temperature.Skin temperature is an effective indicator of thermal sensation.A linear relationship model between overall thermal sensation and mean skin temperature,considering both ambient temperature and exposure time,was established in the non-thermal equilibrium cold environment,which makes the evaluation of thermal sensation more objective.

Impact of summer office set air-conditioning temperature on energy consumption and thermal comfort

To explore the relationship between summer office set air-conditioning temperature and energy consumption related to air conditioning use to provide human thermal comfort,a comparison experiment was conducted in three similar offices at temperatures of 24,26 and 28 ℃ respectively. A thermal comfort questionnaire survey was conducted. It is demonstrated that air-conditioner energy consumption at the set temperature of 28 ℃ is 113% and 271% lower than at 26 ℃ and 24 ℃,respectively. A linear relationship exists between air-conditioner energy consumption and the indoor and outdoor temperature difference. When comfortably dressed,over 80% of research participants accept the set temperature of 28 ℃. The regression analysis leads to a neutral temperature of 26.2 ℃ and an acceptable temperature of 28.2 ℃ for over 80% of the research participants subjects,indicating that the current 26 ℃ set temperature for offices in summer,required by Chinese General Office of the State Council,can be increased to 28 ℃. Moreover,analysis of predicted mean vote(PMV) index shows that a set temperature of 27 ℃,not 26 ℃,is sufficiently comfortable for office staff wearing long-sleeve shirts,long pants and leather shoes.

Analysis and forecast of residential building energy consumption in Chongqing on carbon emissions

Carbon emissions mainly result from energy consumption. Carbon emissions inevitably will increase to some extent with economic expansion and rising energy consumption. We introduce a gray theory of quantitative analysis of the energy consumption of residential buildings in Chongqing,China,on the impact of carbon emission factors. Three impacts are analyzed,namely per capita residential housing area,domestic water consumption and the rate of air conditioner ownership per 100 urban households. The gray prediction model established using the Chongqing carbon emission-residential building energy consumption forecast model is sufficiently accurate to achieve a measure of feasibility and applicability.

Role of urban remnant evergreen broad-leaved forests on natural restoration of artificial forests in Chongqing metropolis

The effects of urban remnant natural evergreen broad-leaved forest (EBLF) on the restoration of artificial pine forests surrounding it were studied with reference to species composition,biodiversity,dominant species and stand structure on Mt. Tieshanping in Chongqing metropolis,Southwest China. The seeds from the remnant EBLF naturally facilitate the restoration process of artificial Pinus massoniana forests near it. The similarity of species composition between the artificial Pinus massoniana forests and the remnant EBLF and biodiversity index of the artificial Pinus massoniana forests decrease as the distance from the remnant EBLF increases. Castanopsis carlesii var. spinusa is the dominant species in the ground vegetation,shrub layer and sub-tree layer of the Pinus massoniana forests near the remnant EBLF. However,the natural restoration processes of those farther away from the remnant EBLF are restricted for the absence of seed source of the inherent components of the remnant EBLF,and the anthropogenic measures should be taken to facilitate the restoration process.

THE INFLUENCE OF IMPURITIES ON THE DISSOLUTION OF CA- AND SR-BEARING BARITE AT ROOM TEMPERATURE

The reaction path in the (Ba, Sr, Ca)SO-4 solid-solution aqueous-solution (SSAS) system was experimentally studied using a batch-reactor method. The effect of the impurities "fluorite" and "iron sulfides" admixed in a natural barite sample on the reaction path was followed by analyzing the aqueous solution continuously. The dissolution and precipitation of the impurity "fluorite" affected strongly the reaction path in the SSAS system, especially the Ca/Sr/Ba ratio in the aqueous solution. This influence became stronger with decreasing CaSO-4 in the solid solution. The dissolution and precipitation of fluorite could hinder the CaSO-4 component from dissolving into water, and reduce the release rate of SO{2-}-4 from the solid solution to the aqueous solution and the removing rate of Ba{2} from the aqueous solution. In the presence of fluorite and sulfides, the aqueous Ba{2} and Sr{2} concentrations were controlled by the dissolution-precipitation of the end-members BaSO-4 and SrSO-4, respectively; the aqueous F-, Ca{2} and SO{2-}-4 concentrations were controlled by the dissolution-precipitation of fluorite. The incongruent dissolution of the (Ba, Sr, Ca)SO-4 solid solution caused the solid phase to become progressively more enriched in the more insoluble component (BaSO-4), while the aqueous composition shifted towards the more soluble end-members (SrSO-4 and CaSO-4) as equilibrium was approached to.

Embodied coefficient of energy carriers and its calculation method

To quantify the energy consumption in the process of production,transportation and processing of energy carriers,the life cycle of building energy used can be divided into two phases:on-site phase and embodied phase.As for the embodied phase,with the data in existing statistic yearbook,the consumption items of energy production and transportation were investigated.And based on the life cycle theory,an embodied coefficient of energy carriers was proposed to quantify the embodied energy consumption.Moreover,a calculation method for the embodied coefficient of energy carriers was deduced using Leontief inverse matrix based on the existing data sources.With relevant data of 2005-2007 in China,the embodied coefficients in 2005-2007 were obtained,in which the values for natural gas and thermal power are around 1.3 and 3.1,respectively;while they are 1.03-1.08 for other selected energy carriers.In addition,it is also found that the consumption in the production and processing accounts for more than 75%.

Heat transfer performance of fresh-air handing device using earth energy

In order to reduce the fresh-air handing energy consumption,a fresh-air handing device using earth energy was presented. The major part is a double pipe soil-air heat exchanger. Its performance was tested in summer and winter. The results show that while the volume of the treated fresh-air is 125 m3/h,in summer,at the outlet of the device,the air temperature is 21.5-24.0 ℃,the air humidity ratio is about 17 g/kg,the greatest temperature drop is about 9 ℃ ,and the largest dehydration quantity is about 6 g/kg. In winter,at the outlet of the device,the air temperature is 15-17 ℃,the air humidity ratio is about 11 g/kg,the largest temperature rise is about 11 ℃,and the largest humidification quantity is about 6 g/kg. Therefore,the application of this new fresh-air handing device can take full advantage of the natural energy,thus effectively reduce the traditional energy consumption for fresh-air handing.

Field study of thermal comfort and preferences in air-conditioned offices in Chongqing,P. R. China

A large-scale field survey to measure indoor environmental parameters such as air temperature,air velocity and relative humidity was conducted in Chongqing,P. R. China,a city in a hot summer and cold winter zone. Subjective questionnaires and the ASHRAE seven-point thermal sensation scale were used to evaluate thermal,humidity and velocity sensations. Probability methods were employed to calculate the preferred temperatures. The results show that the preferred temperatures are 25.1 ℃ in summer and 21.1 ℃ in winter,respectively. Based on a comparison of the difference between neutral and preferred temperatures,it is proposed that human temperature sensitivity influences preferred temperature.

Outdoor thermal environmental research of the mountainous city by GIS

The study of urban outdoor thermal environment was carried out in one of the mountainous cities by using geography information system(GIS) technique which is connected with predicting and evaluating models for the outdoor thermal environment, monitoring data and simulating data. A prediction and evaluation system were set up. A typical mountainous city, i.e., Yunyang city in Chongqing in China, was taken as an example, its urbanization trend and population growth was predicted and evaluated. The heat island intensity and its trend were simulated, the temperature field, velocity field and the humidity field were analyzed. The results show that GIS is an effective tool to deal with the outdoor thermal environment, especially for the mountainous cities with special geographical particularities. GIS can be used in the environmental management and the city planning especially for the mountainous cities.

Artificial neural network modeling of water quality of the Yangtze River system:a case study in reaches crossing the city of Chongqing

An effective approach for describing complicated water quality processes is very important for river water quality management. We built two artificial neural network(ANN) models,a feed-forward back-propagation(BP) model and a radial basis function(RBF) model,to simulate the water quality of the Yangtze and Jialing Rivers in reaches crossing the city of Chongqing,P. R. China. Our models used the historical monitoring data of biological oxygen demand,dissolved oxygen,ammonia,oil and volatile phenolic compounds. Comparison with the one-dimensional traditional water quality model suggest that both BP and RBF models are superior; their higher accuracy and better goodness-of-fit indicate that the ANN calculation of water quality agrees better with measurement. It is demonstrated that ANN modeling can be a tool for estimating the water quality of the Yangtze River. Of the two ANN models,the RBF model calculates with a smaller mean error,but a larger root mean square error. More effort to identify out the causes of these differences would help optimize the structures of neural network water-quality models.

Impact of light-weight external thermal insulation materials on building surrounding thermal environment in summer

The method for calculating wall surface heat storage coefficient was introduced,and the coefficients of several common walls with light-weight external thermal insulation materials and the traditional solid clay brick wall were calculated.In order to study the impact of light-weight external thermal insulation materials,a contrasting experiment was carried out between an external insulated room and an uninsulated room in August,2010,in Chongqing,China.The result shows that outside surface heat storage coefficient of the insulated wall is much less than that of the traditional wall.However,during sunny time,the surface temperature of external walls of the insulated room is obviously higher than that of the uninsulated room.In different orientations,due to different amounts of solar radiation and being irradiated in different time,the contrasting temperature difference(CTD) appears different regularity.In a word,using light-weight external thermal insulation materials has a negative impact on building surrounding thermal environment and people's health.Finally,some suggestions on how to eliminate the impact,such as improving the surface condition of the building envelop,and plating vertical greening,are put forward.

Utilization of municipal solid waste incineration fly ash in lightweight aggregates

Washing pre-treatment of municipal solid waste incineration(MSWI) fly ash blended with shale and sludge was utilized in the manufacture of light-weight aggregates and processed to form ceramic pellets.A formula uniform design was performed to arrange the mixture ratio of the materials.The optimal mixture ratio of the materials was determined by measuring the bulk density,granule strength,and 1 h water absorption of the pellets.It is shown that the optimal mixture ratios of materials,MSWI fly ash,shale,and sludge,are 23.16%,62.58%,and 14.25%(mass fraction),respectively.The performance testing indicators of light-weight aggregates are obtained under the optimum mixture ratio:bulk density of 613 kg/m3,granule strength of 821N,and 1 h water absorption of 11.6%,meeting 700 grade light-aggregate of GB/T 17431.2-1998 standard.The results suggest that utilization of MSWI fly ash in light-weight aggregates is an effective method and a potential means to create much more values.

Heat balance of solar-soil source heat pump compound system

Based on the state-of-the-art studies of solar-soil source heat pump compound system,operation patterns of solar-soil compound system were analyzed,particularly the advantages of parallel operation pattern.It is found that parallel operation pattern is better for solar-soil compound system.Furthermore,the heat balance issue of solar-soil compound system was emphatically analyzed from four aspects,which were annual analysis of heating and cooling load,the heat exchange of ground heat exchanger,capacity determination of solar-assisted heat source and heat balance calculation of solar-soil compound system.Moreover,annual rate of heat balance in a solar-soil source heat pump compound system was calculated with a case study.It is shown that the annual heat unbalance ratio is 19%,which is less than 20%.As a result,the practical solar-soil compound system can basically maintain the heat balance of soil.

Energy saving effect of building envelope in summer

To explore the energy saving effect of building envelope,the experiments were carried out through a comparison of basic cubicle in summer.Experiments show that if energy efficiency measures are applied only in the external walls and windows,the energy saving cubicles have an average energy efficiency ratio of 27.75% and 27.05% when the air change rates are 1.1 and 1.4 h-1 in summer,with both values being over the standard target value by 25%.And the indoor air temperature of the energy saving cubicle is below that of the basic cubicle.The daily mean temperature difference between the interior surface of insulation wall and no insulation reaches 1.47 °C,and the mean temperature difference is up to 8.52 °C between the interior surface and exterior surface of insulating glass and single glass.The two cubicles were simulated for energy consumption using VisualDOE4.0 software under real weather conditions in summer.The results show that the mean deviation is 10.02% between experimental and simulated energy efficiency ratio.The correctness and validity of simulation results of the VisualDOE4.0 software are proved.

Impact of indoor thermal comfort on physiological parameters of human body

With the living standards gradually improved,the buildings with safe,comfortable,healthy indoor thermal environment would be the ideal pursuit. But to create the preferable indoor thermal environment,it is necessary to research physiological influence of indoor thermal environment on human body. So a typical region of hot-humid climate in Chongqing,China,was considered as the object to study physiological indexes of human body. And the indoor thermal environment parameters and physiological indexes of human body were the main measurements. 20 volunteer students were organized to take part in the experiments in the laboratory during this summer. And two methods,physical measuring and questionnaire investigation,were used in the experiments. The results show that the increase in indoor air temperature reduces the uncomfortable feeling of air draft. Indoor air temperature has visible effects on MCS (motor nerve conduction speed),SCS (sensory nerve conduction speed),HR (heart rate),the ECG (electrocardiogram)-QT segment and SSEP (short somatosensory evoked potential)-latent period of N9. Therefore,a safe,comfortable and healthful indoor environment can be created by considering these factors.

Thermal comfort in naturally ventilated indoor environment in hot and humid climate zone in P. R. China

To identify human thermal comfort in naturally ventilated buildings,the research based on both subjective and objective data was carried out in Chongqing,P. R. China. The characteristics of subjects' clothing regulation function,changes of actual mean thermal comfort vote (AMV) varying with time and acceptable operative temperature in natural conditions were analyzed. In addition,the indicator actual mean vote-actual percentage dissatisfied (AMV-APD) was used to study the actual dissatisfaction with thermal environment. The results indicate that regulative ability by changing clothing under natural ventilated conditions is very significant but limited simultaneously,about 1.7 ℃ per 0.1 clo. Under naturally ventilated conditions,people may have an acceptable operative temperature of 16-28 ℃. Based on the AMV-APD,the actual minimum percentage dissatisfied can reach 4% at AMV of -0.36.

Method for acquiring part load distribution coefficient of air conditioning system

This paper presents a method to acquire runtime distribution ratio of building air conditioning system under part load condition (part load coefficient of system) through practical energy consumption data. By utilizing monthly energy consumption data of the entire year as the analysis object,this paper identifies data distribution,verifies distribution characteristics and analyzes distribution probability density for the issue of running time distribution ratio of air conditioning system in part load zones in the whole operation period,thus providing a basic calculation basis for an overall analysis of energy efficiency of air conditioning system. In view of the general survey of public building energy consumption carried by the government of Chongqing,this paper takes the governmental office building as an example,the part load ratio coefficient corresponding to practical running of air conditioning system of governmental office building in Chongqing is obtained by utilizing the above probability analysis and the solving method of probability density function. By utilizing the ratio coefficient obtained using this method,the part load coefficient with any running ratio of air conditioning system can be obtained according to the requirement of analysis,which can be used in any load ratio for analyzing running energy efficiency of air conditioning system.

Application of natural ventilation of residential buildings in hot-humid regions

The current ventilation condition of the hot and humid regions was analyzed through on-site investigation. It is found that residents in this region expect to improve indoor thermal environment through natural ventilation as much as possible. Then,it comes to a conclusion by the field test that natural ventilation has certain practical effect on improving indoor thermal environment. CFD simulation software is employed to verify the test result. Based on PMV modified model,and according to norms,geography and climate combined with the measured and simulated results,the application of the time and effectiveness of natural ventilation in hot and humid region were analyzed,to some extent,providing a basis for reducing the air-conditioner's runtime with natural ventilation.

Thermal environment analysis of mountainous towns based on GIS

Outdoor thermal environment prediction and evaluation system was established based on a geographic information system. The system uses digital elevation model data and satellite imagery of mountainous towns. The system can conveniently provide a three-dimensional view of a town as well as predict the urbanization rate and urban heat island intensity. In addition,the system also permits quick inquiry and analysis of the temperature field,moisture field,and wind field tendency and current conditions of towns. The system was tested using the town of Yunyang,Chongqing Municipality,China,as a case study. The system was used to analyze and predict the climate comfort of the entire town and the outdoor thermal environment comfort of certain town districts,squares and streets. The results are in accordance with the measured data. This outdoor thermal environment prediction and evaluation method thus can provide a feasible reference for the general plan of mountainous town and promote the sustainable development of mountainous towns.