Chihui Zhu

Based on the Weber/Fechner's law and PMV, the study puts forward the composition principle of indoor air quality evaluation index, and defines carbon dioxide sub-index PMV CO2, respirable suspended particulate sub-index PMV PM10, formaldehyde sub-index PMV HCHO, and indoor air quality index PMV IAQ. On the basis of indoor air quality comfort evaluation experiment and literatures, the rationality of these models is verified. Compared with the environmental parameters, the new defined comfort evaluation index models establish the link between the objective environment parameters and subjective comfort evaluation and unify the metrics of indoor environmental factors. If other environmental parameters are involved in the evaluation, the corresponding index can be built in the same way.

The purpose of this study was to determine the influences of environmental parameters on common health symptoms in office buildings. A grey preference analysis based on a new indoor environment quality (IEQ) index and a controlled field survey of 91 office occupants were conducted in an office building in Guangzhou, China. The new IEQ index based on Weber/Fechner’s law and predicted mean vote (PMV) was developed and validated by our survey. In the survey, the six environmental parameters (air temperature, illumination intensity, noise level, carbon dioxide, formaldehyde and PM 10 ) were measured. The subjects’ satisfaction levels and the nine health symptoms (eye dryness, lethargy, dry throat, headache, nausea, skin dryness, blocked nose, influenza-like symptom and chest tightness) were determined using questionnaires. The results show that the proposed IEQ index can preferentially predict the subjective sensations of occupants. PM 10 was identified as the most significant environmental parameter, followed by formaldehyde, air temperature, carbon dioxide, noise level and illumination intensity. Eye dryness and lethargy were the most significant symptoms, followed by dry throat, headache, nausea, skin dryness and chest tightness. Blocked nose and influenza-like symptom were hardly reported by subjects. The findings of this study could provide a practical guidance for IEQ management to reduce unhealthy diseases for occupants.

Building-integrated photovoltaic/thermal (BIPV/T) systems can produce both electrical and thermal energy through the use of photovoltaic/thermal modules integrated with building envelope. Exterior shading is a common way to improve summer indoor thermal environment of the buildings in low latitudes. This study presents a BIPV/T solar water heating system for exterior shading of residences. In order to evaluate and optimize the system performances, a model was developed to simulate the thermal and electrical production of such system. The simulations for an example system in Guangzhou, a city in South China, were performed to investigate the influences of tank installation height and panel tilt angle on system performances. According to simulation results, the suggested tank installation height is 0.6~0.8 m. The shading coefficient ranges from 0.797 to 0.828 when the tilt angle varies from 14° to 38°. The reduction of panel tilt angle causes a certain improvement of shading performance. The annual auxiliary heat reaches the minimum when the panel tilt angle equals 28°, and the annual electric energy output changes little when the panel tilt angle ranges from 20° to 28°. Comprehensively considering thermal, electrical, and shading performances, the suggested panel tilt angle is 20°~28°. The average thermal and electrical efficiencies are respectively 38.25% and 11.95% when the panel tilt angle ranges from 20° to 28°. The presented system is a promising way to provide hot water, electricity, and exterior shading for residences.

The indoor air pollutants grey clustering model is proposed to simplify the evaluation of indoor air quality. Because grey absolute relational grade can express the correlation in resource and dissemination characteristics between different indoor air pollutants, so the grey incidence matrix constituted by grey absolute relational grades can be used to group pollutants. Case studies of Shanghai, Shenzhen office verify that the model is reasonable. And case studies show, for office buildings, CO2, RSP, HCHO can be selected as indicator pollutants. Because each indicator represents a class of pollutants which are similar in source and dissemination characteristics, index set induced not only avoid unreliability due to too small indicators, but also overcomes excessive high cost and complex process caused by too many indicators.