Zhaojun Wang

Harbin Institute of Technology | HIT · School of Municipal and Environmental Engineering

Heating and cooling in buildings accounts for over 20% of total energy consumption in China. Therefore, it is essential to understand the thermal requirements of building occupants when establishing building energy codes that would save energy while maintaining occupants’ thermal comfort. This paper introduces the Chinese thermal comfort dataset, e...

People spend most of their time indoors. However, indoor temperature and individual thermal exposure are generally not considered in epidemiological studies of temperature and health. Based on the American Society of Heating, Refrigerating, and Air-Conditioning Engineers (ASHRAE) RP-884 Database, the ASHRAE Global Thermal Comfort Database II and th...

Guidelines for low energy building design based on the adaptive thermal comfort concept - Technical report: IEA EBC Annex 69: Strategy and Practice of Adaptive Thermal Comfort in Low Energy Buildings. The adaptive thermal comfort concept has been developed over many years and proven in numerous field studies (e.g. Webb 1964, Nicol and Humphreys 1...

In order to explore the acceptable temperature limits of humans in temperature ramps by intermittent heating in the north China, the research was conducted in an office-lab. Four indoor dynamic heating environments with different initial temperatures (15–18 °C) and change rates (0.02–0.18 °C/min) were created. The room temperature gradually rose as...

The predicted mean vote (PMV) and its several revised models are widely used for the prediction of thermal comfort. This study aims to assess their performances using the Chinese Thermal Comfort Database (N = 41977). In air-conditioned buildings, the PMV prediction accuracy (P) and the mean absolute error (MAE) are 41.2% and 0.86, respectively, whi...

Air-source heat pumps (ASHP) are increasingly used to improve space heating. However, few relevant studies have focused on the rural residential buildings that use ASHP air-conditioners for heating conditions. Therefore, this paper presents experiments and numerical simulations to analyse the impact of ASHP air-conditioners on the indoor thermal en...

Asymmetry thermal radiation from a cold surface, could easily cause local thermal discomfort and even health problems, such as knee osteoarthritis. An experiment with subjects was conducted to study the radiant asymmetry caused by a cold wall at a room temperature of 18 °C, which is the lower limit of the room temperature for heating design in Chin...

This paper compares indoor thermal environment and thermal comfort between radiant and convective systems in continuous operating mode using large field test samples from Chinese Thermal Comfort Database. Hypothesis tests are performed to compare thermal environment parameters and human subjective responses. We are concerned not only with statistic...

Adjusting clothing for changing climates is an effective way for the perseverance of human thermal comforts. In this study, the clothing insulation (Iclo) of occupants and their thermal adaption to cold climates are discussed based on the Chinese Thermal Comfort Database. Particularly, the raw data was selected from five climate zones of China: sev...

In winters of the severe cold areas, low surface temperatures of exterior building elements (both opaque and transparent) can easily cause cold radiation to the indoor environments and lead to local discomfort of inhabitants. Therefore, not only the non-condensation on the walls is required in the building thermal design, but also the demand to sat...

To prevent the downdraft of windows, the radiator heating temperature needs to be sufficiently high. The prevailing method of estimating the radiator temperature is based on the principle that the reference velocities of natural convective flow over the radiator and window are comparable. However, this method overestimates the heating temperature,...

Large space buildings play a significant role in modern society because of their environmental advantages and market value. While the zonal model is promising for the efficient and rapid evaluation of the stratified thermal environment, there is a lack of a reasonable and convenient zoning strategy with the advent of modern computing. This paper pr...

Traditional building design education in the disciplines of building services, civil engineering, mechanical engineering, etc. focusses on quantifiable factors, i.e. factors which can be subject of calculation, simulation and dimensioning. Since non-quantifiable factors are not part of calculation or simulation models, there is a tendency that they...

Stack-driven airflow is extensively utilized to improve thermal comfort and exploit energy saving potential during summertime. However, the thermal environment in large spaces is obviously stratified, and the stack ventilation is complex and dynamic. This paper presents a practical zonal stack ventilation method by combining the merits of the intui...

Radiator heating (RH) and floor heating (FH) exhibit disparate indoor asymmetric environments. In addition, the indoor microenvironment at different locations remarkably varies owing to the cold radiation generated by the surface of exterior walls and windows (EWWs) in winter in the severe cold region of China. The impacts of the exposure distance...

Adaptive thermal comfort guidelines have been developed within the work of Annex 69: "Strategy and practice of adaptive thermal comfort in low energy buildings". The guidelines have been established based on a framework for adopting adaptive thermal comfort principles in building design and operation developed by the authors. The guidelines target...

Severe haze episodes characterized by fine particles have occurred frequently in severe cold areas of China during the winter, which poses a serious health concern to humans. Currently, there is an increasing trend in China to build energy efficient passive houses that are capable of tolerating poor outdoor air pollution with tighter envelopes etc....

Window opening behaviors influence natural ventilation and thermal comfort greatly and add huge uncertainty of energy consumption. So, it is essential to propose realistic behavior models. Many researches have been focused on behaviors in dwellings. But there exists big difference between residential and office buildings, and survey in offices shou...

Kang heating mode at rural houses in China is quite different from central heating system in urban areas. The relevant conclusions drawn from the research on thermal comfort of urban residential buildings are not applied to rural houses. It is necessary to study indoor thermal environment and thermal comfort at rural houses in China. A field study...

In order to accurately design a healthy indoor environment, it is important to consider spatial distributions of particles. In this paper, with a simplified passive household as a physical model, the concentration fields of the PM2.5 in displacement ventilation were simulated by CFD, to analyze the influence of smoking and cooking on indoor PM2.5 d...

One of the major challenges of building industry today is to provide indoor spaces allowing the occupants to make themselves comfortable while achieving low energy consumption. Considering the observed increasing temperatures and a more extreme climate, this becomes even more urgent and difficult to accomplish. It is therefore necessary to rely on...

Recognizing the value of open-source research databases in advancing the art and science of HVAC, in 2014 the ASHRAE Global Thermal Comfort Database II project was launched under the leadership of University of California at Berkeley's Center for the Built Environment and The University of Sydney's Indoor Environmental Quality (IEQ) Laboratory. The...

Harbin is in the severe cold climate zone in China, where the outdoor air temperature is low in winter. The central heating system without terminal control is used in buildings in the area. A field study on thermal comfort was conducted in four types of buildings in Harbin during a same winter. Due to the broad range of outdoor air temperatures and...

To survey the indoor particulate matter in a passive low energy consumption residential building in the severe cold area of China, a field study was conducted in Harbin during the winter of 2015~2016. The indoor and outdoor concentrations of PM10 and PM2.5 as well as outdoor air flow rates were tested, and the subjective evaluation on indoor air qu...

An investigation on indoor air quality was carried out in urban apartments in Harbin, China. The indoor and outdoor concentrations of PM2.5, PM10, CO, CO2, SO2, NOX, TVOC, HCHO and NH3 were monitored. Simultaneously, questionnaire surveys on the indoor perception of air quality among occupants were conducted. In addition, a continuous measure on in...

The winter in the severe cold area of China is long and cold. The mean outdoor temperature is about −10.0 °C during the winter in Harbin, while the indoor air temperature is often above 24 °C. How does the indoor environment influence human thermal comfort and adaptation in such an overheated environment? A combined approach of spot-reading measure...

Along with the improvement of living quality, indoor thermal comfort has been drawing increasing attentions. In this paper, a comparison between South Europe, North America and Asia on winter indoor thermal environments, occupants' clothing insulations and their thermal sensations was conducted. The compared regions all locate in similar latitude r...

The heating period is very long in Harbin in China. This paper describes a field study in university classrooms and dormitories in heating period in Harbin. The survey shows that the neutral temperature in classrooms at 3 periods was 17.7̊C, 19.3̊C and 19.4̊C, and in dormitories the neutral thermal temperatures were 20.9̊C, 21.8̊C and 21.2̊C, respe...

In this paper, a mathematical model of connection method between ring-shaped heat-supply systems with multi-heat sources was established based on the requirement of limited-heating in accident conditions. The limited-heating coefficient, pressure bearing capacity of pipeline, heating capacity of heat source, operating parameters of circulating pump...

A field investigation was carried out in a university campus in Harbin winter to study students' thermal comfort and adaptation. 30 students were selected as the participants. They were tracking surveyed and their environmental parameters were monitored in dormitories and classrooms. The results show that the indoor air temperatures were close to t...

A field survey was conducted on students’ thermal comfort in typical university dormitories from the late autumn to the early spring covering the whole space heating period in Harbin, China. It aims to research the influence of climatic adaptation and indoor thermal history on university students in the severe cold area of China. The indoor physica...

Harbin is located in Chinese severe cold area. Local people stay indoors by most of time in winter. The occupants’ behavioural regulation was greatly different between residents and office staffs, which might lead to the differences of human thermal responses. A field study was conducted in residential and office buildings from September 2013 to Ma...

This paper focuses on a field investigation on indoor environment at a rural passive solar house in Yushu City, Jilin Province in the severe cold region of China. The air temperature and relative humidity at the solar house were monitored from Dec. 15th, 2014 to Mar. 15th, 2015. During the period, the authors went to the solar house every 3 or 4 we...

To explore the indoor air pollution at rural houses in severe cold region in winter, a field study was conducted at 10 rural houses in two villages around Harbin. The indoor pollutants including PM2.5, PM10, CO, CO2, SO2, NOx, TVOC and NH3 were tested and the correlation of pollutants were analyzed. The results showed that PM2.5, PM10, SO2, NOx, CO...

This study aimed at investigating the thermal comfort and thermal sensation of subjects in an asymmetric radiant thermal environment; 16 healthy subjects were participated in the experiments. According to the results in non-uniform environments with the cold radiation of outer window and floor heating, the local thermal sensations of body parts wer...

In order to investigate indoor thermal environment and thermal comfort at rural houses, a field study was carried out at 10 rural houses in 2 villages near Harbin from December 2012 to January 2013. The environmental parameters and the subjects’ thermal sensation were collected simultaneously. The results showed that the indoor air temperature rang...

Chinese Kang is one of the most important heating facilities at rural houses in China. The biomass materials such as wood and straw are the primary fuels, which release many pollutants. Inadequate ventilation prevents the pollutants from discharging out. In this study, we investigated the indoor air quality at rural houses in severe cold region of...

Many previous studies on human thermal and physiological sensation were done in the box-like chambers which are different from the real environments. The subjects wore summer clothing in the earlier studies which was different from Chinese northern people's clothing in winter.In order to investigate the effect of cold radiation from the outer windo...

In China, adding space heating in residential buildings is normally scheduled at the end of October each year, with heat supplied by district heating systems. This paper describes a field study of thermal comfort conducted in Harbin during the winter from 2009 to 2010 before and after the space heating is added. The aim is to study human responses...

This field study was conducted during summer 2009 in Harbin, northeast of China in order to investigate human responses to the thermal conditions in naturally ventilated residential buildings in cold climate. We visited 257 families in six residential communities and collected 423 sets of physical data and subjective questionnaires. The neutral tem...

In moderate climates night ventilation is an effective and energy-efficient approach to improve the indoor thermal environment for office buildings during the summer months, especially for heavyweight construction. However, is night ventilation a suitable strategy for office buildings with lightweight construction located in cold climates? In order...

On the base of ANSYS simulation of heat transfer and the theory of moisture permeation, moisture transfer of two slotted light steel-framed composite walls is calculated. The factors which affect moisture accumulation of insulation material during heating period, such as insulation material, finishing material, thickness of insulation layer, indoor...

Based on the theory of moisture permeation, moisture transfer of the slotted light steel-framed composite wall is analyzed. The results show that the condensation of moisture is easily occurred in the insulation layer far away from the steel-framed component and its moisture accumulation is also more than that of other places. From the point of moi...

The sectional parameters of the slotted light steel-framed composite wall include the flange width, frame thickness, frame width and frame distance. Hear transfer among the composite wall was simulated as the changes of sectional parameters. The results show that the frame thickness and frame width can influence heat transfer evidently, while the f...

This field study was performed during the winter of 2000–2001 in order to investigate the thermal environment and thermal comfort in residential buildings in Harbin, northeast of China. A total of 120 participants provided 120 sets of physical data and subjective questionnaires. An indoor climate analyzer and a thermal comfort meter made in Denmark...

A mathematical and physical model on night ventilation is set up. The fields of indoor air temperature, air velocity and thermal comfort are simulated using Airpak software. Some main influencing factors of night ventilation in office rooms in Harbin are simulated and analyzed. The results show that the inlet velocity and area can influence the eff...

This paper presents the main findings of Project HIT.2000.25 supported by the Scientific Research Foundation of Harbin Institute of Technology, a field study of indoor climates and occupant comfort in 66 residential buildings in Harbin, located in northeastern China. One hundred and twenty sets of questionnaire responses were provided from 120 subj...

As a new way of air conditioning, task air conditioning (TAC) system is often used in combine with background air conditioning (traditional central air conditioning) system. In this research, the Computational Fluid Dynamics (CFD) technique is used to analyze the impact on thermal environment of task zone when these two air conditioning systems are...

The three-dimensional heat transfer performance of the slotted light steel-framed composite wall at minimum temperature is simulated using the finite element software of ANSYS. Based on the simulated results of heat transfer and the theory of moisture permeation, moisture transfer of the composite wall is calculated. The results show that there is...