Study on Simulation Method of Heating and Air - conditioning Energy Consumption of Residential Buildings

The heating and air conditioning energy consumption of residential buildings is influenced by the behavior of indoor living personnel.On the basis of research and analysis,two kinds of calculation modes reflecting the behavior of indoor living personnel are estimated.Under two kinds of different calculation modes,by using the building thermal environment simulation Toolkit DeST to simulate the energy consumption calculation for certain residential building in Shanghai,and the simulation results are compared with the research results.The influence of calculation mode on heating and air conditioning energy consumption of residential buildings in Shanghai is analyzed in this paper.In order to obtain the right simulation calculation method correctly reflecting the energy consumption of residential buildings.This method can be used for analysis and evaluation of heating and air conditioning energy consumption of residential buildings in Shanghai,and it can serve as instruction for right energy design of residence building.     

Performance in Full Fresh Air Mode of Centralised Air-conditioning System for Shopping Malls in Chinas Hot Summer Region

Based on the analysis of the outdoor weather condition in Chinas hot summer region, it is found that the full fresh air mode can work in the whole winter and half of the time in transition season. Thus, about 30%-60% runtime of the artificial cold source can be reduced. It studies the control strategies at different conditions of indoor load, ventilation and indoor air temperature and humidity by analyzing two control modes-enthalpy control and temperature control. It shows that the higher the indoor load is, the more efficient the full fresh air mode is. And the airflow is better to be set as 6~8 h-1. Since the indoor air parameter has great influence on energy saving, it is necessary to set different indoor air parameters in different seasons by taking the effect of temperature difference on human thermal comfort into consideration. It is also found that the enthalpy control mode can be used in winter and in transition season, while the temperature control mode can be applied in summer. If the full fresh air mode were adopted, it would cut down the energy consumption by 100~180 kWh/m2 and the carbon emission by 30~50 kg/m2 each year.     

Acceptable Temperature Range of Indoor Environment without Air Conditioning and Heating in Hot Summer and Cold Winter Zone

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.     

Effects of Operation Mode of Air Conditioning on Energy Consumption of Heating and Air Conditioning in Residential Buildings

By using the building thermal environment simulation Toolkit DeST to simulation calculation of a residential building in Shanghai,the quantitative relationship between the factors of operation mode of air conditioning affecting the energy consumption of heating and air conditioning in residential buildings has been obtained in this paper,moreover,it has come to a conclusion that the tolerable temperature is superior to control temperature of air conditioning in respect of sensitivity and the living mode of indoor personnel has certain effect on the cold energy consumption.     

Numerical study of airflow distribution in air-conditionedtrain in Qinghai-Tibet Railway

To obtain the influence of outer environmental condition on the indoor airflow distribution for the 25T air-conditioned train in Qinghai-Tibet, the Realizable k-ε model is adopted to numerically analyze the indoor temperature and velocity fields of the running train. The results indicate that solar radiation has great effect on the indoor temperature field and it is meaningful for improving the thermal comfort to adjust the air supply parameters with the outer environmental condition. Under different air supply conditions, it is the conjugating relation between the indoor temperature field and velocity field that leads to different thermal comfort in different regions of the running train. In addition, the operating modes exchange under different outdoor environmental conditions is also discussed and some additional functions of the using air-conditioning system are put forward too.     

Operational Parameters of Hybrid Radiant Cooling Floor and Displacement Ventilation Air Conditioning System

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.     

Influence of Indoor Temperature and Humidity on Thermal Comfort and Energy Consumption of Air-Conditioning Systems

Taking a central air-conditioning system as an example,this paper presents the influence of indoor design temperature and relative humidity on thermal comfort and energy consumption in an office building in Guangzhou,P.R.China.The study shows that under the identical indoor thermal comfort conditions,the air-conditioning system cooling load increases with the increase of indoor temperature.Increasing the indoor temperature can not decrease energy consumption.In order to reduce the energy consumption in a central air-conditioning system meeting the required indoor thermal comfort condition,an indoor design condition with larger relative humidity and lower temperature is recommended.     

THE WAYS FOR IMPROVING INDOOR ENVIRONMENT AND AIR-CONDITIONING SYSTEMS IN DANCLING HALLS

Since 1988, air temperature, humidity, air quality, noise level and intensity of illumination in lots of dancing halls in China have been investigated and tested. This paper introduces the present situation of indoor environment and air conditioning systems in dancing halls of China. The design indexes of cooling load for room and ontside air are recommended. The reasons for indoor environment deterioration have been found out. From the actual situation of China, the ways for imoroving indoor environment and approach of energy conservation in air conditioning systems are explored.     

Ventilation regulating methods adapting by climate for residential housing

To study the climatic control strategies of the residential building indoor acceptable thermal environment, firstly, based on adaptive model, integrated indoor activities, clothes and spot investigation on air velocity of residential building, this paper calculates an acceptable temperature range. Secondly, through state-space techniques, common passive regulating technologies in residential building have been simulated, including different ventilation rates and divided-period setting ventilation effect on indoor temperature. Meanwhile, monthly regulating methods for ventilation have been proposed. Thirdly, through ventilation technology, effective regulating zone of outdoor climate parameters have been analyzed, which is combined with hythergraph of outdoor temperature, humidity, solar radiation and air velocity. Taking the characteristics of the human thermal comfort adaptability into consideration, the energy-saving potential of the study results is also analyzed.     

Research on Classroom Thermal Environment during the Summer in Chongqing

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.     

Physiological Experiment for Human Thermal Comfort of Air Flow in Summer

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.     

Evaluation and Analysis of Bacteria Pollution in Dwelling Indoor Air

Tests and study were carried out on indoor air bacteria pollution in dwelling house inChongqing city. Based on the data of measured bacteria concentration of the indoor air,the reasons for indoor air pollution were analyzed. Ith was found that the bacteria seriously polluted the indoor air. The main factors influencing the indoor air bacteria pollution are moisture, natural ventilation and lighting conditions. The construction forms and decoration of the dwelling house are the secondary reasons for indoor air bacteria pollution. Measures and suggestions of preventing the indoor air bacteria pollution and improving the indoor air quality and environmental quality were presented.     

A Theoretical Study on Thermal Dynamics Model and the Dehumidification Capacity of Hybrid Desiccant Cooling System with Condensation Heat Recovery

The structure and energy conservation characteristics of hybrid desiccant cooling system with condensation heat recovery are introduced briefly. Based on the first and second law of thermodynamics, a system thermodynamic model is established and the solution process given in a diagram. The dehumidification capacity is calculated under different exergy efficiency and indoor sensible heat conditions. The calculation results show that the desiccant wheel barely can compensate for the humidity load of outdoor air under with a ventilation rate of providing fresh air once per hour; when the fresh air rate of ventilation is limited to 0.5 times per hour, however, the desiccant wheel possess sufficient capacity under relatively large wheel exergy efficiency and high sensible heat load.     

Field Study on The Effects of Indoor Climate on Human Productivity and Its Economical Consequence in ofFice Buildings

In this study we carried out field studies in two office buildings in Shanghai, China to investigate the effects of indoor environmental quality on human productivity. The overall perception of occupants on indoor climate (including thermal sensation, perceived air quality, and perceived noise etc.), the influence of human factors and indoor climate factors on productivity, as well as their sick building syndrome (SBS) symptoms were assessed with subjective questionnaires. The building operating cost and employee’s salaries were record objectively. Meanwhile the indoor air temperature, humidity, air velocity, noise, concentration of formaldehyde and carbon dioxide were measured. The results indicate that about 50% occupants complained SBS symptoms when exposed to their office. Most occupants require to increase fresh air and lower the indoor noise level (especially for open-plan office), even though the physical parameters meet the requirement of standards. Thermal environment, indoor air quality and noise assessed to be the three main indoor climate factors that affect human productivity. The employee’s salaries were over 100 times of the electrical energy cost in this two buildings, which indicate great financial benefit can be achieved in China to increase occupants’ productivity by improving the indoor climate.     

Residential Environment Ethic and Green Building Materials

The environment ethic deals with the research on relation between human beings and the nature. The residential environment ethic is a detail study of environment ethic, which studies the relation between human beings and residential environment. The residential environment ethic presents the human duty to care about and protect residential environment and actually to protect human beings themselves. But the residential environment is facing many dangers, such as city pollution and indoor air pollution, which are closely related to building materials. So, one of the ways for improving the residential environment quality is to use green building materials.     

Discussion on the Application Range of the PMV Equation

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.     

Tests and analysis on energy consumption of heating ventilating and air conditioning systems in commercial buildings

Three typical commercial buildings in Chongqing, P.R. China were selected to study the actual summertime operation and energy situations of heating ventilating and air conditioning (HVAC) systems in commercial buildings. Based on tests of energy consumption of HVAC systems in these three buildings, we analyzed the electricity consumption of the main components of the air conditioning systems. The energy efficiency of the chillers and air conditioning water distribution systems were studied. The indoor thermal environment in these three buildings were also tested and discussed. It is concluded that problems exist in the air conditioning systems of commercial buildings. Among the problems are over sized system design, low equipment operating efficiencies, poor operation management, and lack of indoor temperature controls. To reduce energy consumption of HVAC systems in commercial buildings, we propose energy efficient strategies such as sizing systems based on accurate load calculation and automatic control under partial load conditions.     

Modification for evaluation indexes of air distribution

In order to evaluate the air distribution using CFD method scientifically, former evaluation indexes of air distribution are modified by quality weighting method. A numerical simulation model is developed for the calculation and verified by experiment. Indoor air distribution in four operating modes of ceiling mounted indoor unit is simulated with the model. Comparing the existing evaluation indexes and the modified ones, it is found that significant differences in the indexes result in different evaluation results and the modified ones are more reasonable and appropriate.     

Calculating the Cooling Load of Cars'' Air-Conditioning System

This paper adopts harmonic reaction method to calculate the cooling load of the air conditioning system of the NO.1011A loaded miniature cars in Chongqing Chang'an Automobile Company .The study indicates that harmonic reaction method is more exact than traditional steady method to show the dynamic characteristic of cooling load. The maximum cooling load appears on 2:00 pm, it's 3 098 W. Among the whole cooling load,heat load through windows and heat load through components are the biggest,they occupy 50% of the whole amount. Heat load of air leaks occupies 27.3%,which shows that it is necessary to improve the seal of cars. Chongqing Chang'an Automobile Company develops optimize design for the air condition system with this result, which reaches a perfect climate effect.     

Electre Multi-Attribute Evaluation Model to the Operating Performance of Air Conditioning Systems

An ELECTRE performance evaluation model was developed to outrank the different operating conditions of air conditioning systems. Five evaluation criteria covers total energy consumption, thermal comfort PMV and PPD, indoor air quality indices such as CO2 concentration and TVOC concentration. The performance under seven different operating conditions was outranked on the TRNSYS (transient system) simulation platform. Three assignment alternatives of weight coefficients were selected to calculate the relevant credibility scores respectively. The results indicate that the proposed evaluation model can outrank the different operating conditions and select the optimum one, Moreover different weight assignments have little influence on the outranking scores. Further investigation should focus on the more evaluating criteria such as control performance and others in the comprehensive evaluation of operating conditions.