Plum Rain-Season-Oriented Modelling and Intervention of Indoor Humidity with and without Human Occupancy

Jin Ye; Hua Qian; Xiaohong Zheng; Guoqing Cao

doi:10.3390/atmos10020097

Plum Rain-Season-Oriented Modelling and Intervention of Indoor Humidity with and without Human Occupancy

Atmosphere ◽

10.3390/atmos10020097 ◽

2019 ◽

Vol 10 (2) ◽

pp. 97

Author(s):

Jin Ye ◽

Hua Qian ◽

Xiaohong Zheng ◽

Guoqing Cao

Keyword(s):

Indoor Air ◽

Indoor Environment ◽

Meteorological Data ◽

Internal Source ◽

Mold Growth ◽

Outdoor Air ◽

Rain Season ◽

Reduction Methods ◽

Indoor Humidity

The plum rain season, caused by precipitation along a persistent stationary Mei-Yu front in East Asia, creates favorable temperatures and relative humidity (RH) for mold growth indoors. This paper investigates the effects of human occupancy on indoor humidity and investigates the efficient RH reduction methods to prevent mold growth in moist climates. The research is carried out based on a case study which compares a family-occupied home and another unoccupied one during typical plum rain season in Nanjing. Firstly, by analyzing the factors that can influence the indoor air RH, this paper develops a comprehensive model to evaluate the efficiency of various RH intervention methods. Secondly, this paper collects the meteorological data in Nanjing at different time scales, from days to hours. Thirdly, a specific case study is carried out based on the model and data. The results show that dehumidification and heating can always reduce RH below the critical value under which the mold growth could be inhibited. However, the effects of ventilation are more sophisticated and depend upon the human occupancy, outdoor air temperature, and air change per hour (ACH). In certain unoccupied cases, the ventilation may be inappropriate and may continuously bring moisture outside into the indoor environment, which has adverse effects on mold suppression. In the occupied cases, the condition changes significantly because the human is deemed as an internal source of heat and moist. Special care should be exercised for occupied ventilation in order to determine the optimal ACH and appropriate outdoor temperatures. Finally, some guidance is given to prevent mold growth in the general area that suffers from the plum rain season.

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Mitigation Strategies for Overheating and High Carbon Dioxide Concentration within Institutional Buildings: A Case Study in Toronto, Canada

Buildings ◽

10.3390/buildings10070124 ◽

2020 ◽

Vol 10 (7) ◽

pp. 124 ◽

Cited By ~ 1

Author(s):

Claire Tam ◽

Yuqing Zhao ◽

Zaiyi Liao ◽

Lian Zhao

Keyword(s):

Carbon Dioxide ◽

Air Quality ◽

Indoor Air Quality ◽

Air Temperature ◽

Indoor Air ◽

Indoor Environment ◽

Thermal Conditions ◽

Co2 Concentration ◽

Hvac System

Indoor air quality and thermal conditions are important considerations when designing indoor spaces to ensure occupant health, satisfaction, and productivity. Carbon dioxide (CO2) concentration and indoor air temperature are two measurable parameters to assess air quality and thermal conditions within a space. Occupants are progressively affected by the indoor environment as the time spent indoors prolongs. Specifically, there is an interest in carrying out investigations on the indoor environment through surveying existing Heating, Ventilation, Air Conditioning (HVAC) system operations in classrooms. Indoor air temperature and CO2 concentration in multiple lecture halls in Toronto, Canada were monitored; observations consistently show high indoor air temperature (overheating) and high CO2 concentration. One classroom is chosen as a representative case study for this paper. The results verify a strong correlation between the number of occupants and the increase in air temperature and CO2 concentration. Building Energy Simulation (BES) is used to investigate the causes of discomfort in the classroom, and to identify methods for regulating the temperature and CO2 concentration. This paper proposes retro-commissioning strategies that could be implemented in institutional buildings; specifically, the increase of outdoor airflow rate and the addition of occupancy-based pre-active HVAC system control. The proposed retrofit cases reduce the measured overheating in the classrooms by 2-3 °C (indoor temperature should be below 23 °C) and maintain CO2 concentration under 900 ppm (the CO2 threshold is 1000 ppm), showing promising improvements to a classroom’s thermal condition and indoor air quality.

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Optical Sensing Approach to the Recognition of Different Types of Particulate Matters for Sustainable Indoor Environment Management

Sustainability ◽

10.3390/su122410568 ◽

2020 ◽

Vol 12 (24) ◽

pp. 10568

Author(s):

Hosang Ahn ◽

Jae Sik Kang ◽

Gyeong-Seok Choi ◽

Hyun-Jung Choi

Keyword(s):

Indoor Air ◽

Indoor Environment ◽

Particulate Matters ◽

Outdoor Air ◽

Household Dust ◽

Tree Pollen ◽

Contaminant Source ◽

Pine Tree ◽

Reflected Light ◽

And Control

The indoor environment is a crucial part of the built environment where our daily time is mostly spent. It is governed not only by indoor activities, but also affected by interconnected activities such as door opening, walking and routine tasks throughout the inside and outside of buildings and houses. Pollutant control is one of the major concerns for maintaining a sustainable indoor environment, and finding the source of pollutants is a relatively hard part of that task. Pollutants are emitted from various sources, transformed by sunlight, react with vapor in ozone and are transported into cities and from country to country. Due to these reasons, there has been high demand to monitor the transportation of particulate matters and improve air quality. The monitoring of pollutants and identification of their type and concentration enables us to track and control their generation and consequently discover reliable suitable mitigation measures to control air quality at regulated levels by contaminant source removal. However, the monitoring of pollutants, especially particulate matter generation and its transportation, is still not fully operated in atmospheric air due to its open nature and meteorological factors. Even though indoor air is relatively easier to monitor and control than outdoor air in the aspect of specific volume and contaminant source, meteorological parameters still need to be considered because indoor air is not fully separated from outdoor air flow and contaminants’ transportation. In this study, an optical approach using a spectral sensor was attempted to reveal the feasibility of wavelength and chromaticity values of reflected light from specific particles. From the analysis of reflected light of various particulate matters according to different liquid additives, parameter studies were performed to investigate which experimental conditions can contribute to the enhanced selective sensing of particulate matter. Five different particulate matters such as household dust, soil, talc powder, gypsum powder and yellow pine tree pollen were utilized. White samples were selectively identified by the peak at 720 nm for talc and 433 nm and 690 nm in wavelength for gypsum under chemical additives. Other grey household dust and yellowish soil and pine tree pollen revealed a distinct chromaticity x, y coordinates shift in vector within the maximum range from (0.22, 0.19) to (0.55, 0.48). Applicable approaches to assist current particle matter sensors and improve the selective sensing were suggested.

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A DIGITAL METHOD FOR MEASURING THE THERMAL COMFORT OF THE AIR

Biomedical Engineering Applications Basis and Communications ◽

10.4015/s1016237202000267 ◽

2002 ◽

Vol 14 (04) ◽

pp. 175-181

Author(s):

TANG-JEN LIU ◽

MING-SHING YOUNG

Keyword(s):

Thermal Comfort ◽

Indoor Air ◽

Indoor Environment ◽

Comfort Level ◽

Digital Method ◽

Outdoor Air ◽

Air Movement ◽

Mathematical Expressions ◽

Temperature And Humidity ◽

The Mathematical Model

Opening windows is frequently done to refresh the indoor air for the occupants. To maintain the cleanliness and freshness of the indoor air, more outdoor air is needed. But its high temperature and humidity are harmful to the thermal comfort of the indoor environment. Therefore, determining the amount of outdoor air allowed to enter the room is very important for the optimum conditioning of the indoor air. The ASHRAE comfort charts indicate the percentage of subjects feeling comfortable during various combinations of dry-bulb temperature, humidity, and air movement. A set of mathematical expressions were proposed to model the charts in order to calculate the comfort degree of the outdoor air automatically with its temperature and humidity. In this paper, the measurement of temperature and humidity was completed by a self-developed digital method. Besides, the comfort level of the sampled air was also simultaneously determined by this digital method based on the mathematical model of comfort charts. The system implemented based on our method is portable. This will let us make good use of the outdoor air and controll the ventilation machine more effectively.

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The Impact of Carbon Dioxide Concentration on the Human Health - Case Study

Journal of Applied Engineering Sciences ◽

10.2478/jaes-2018-0008 ◽

2018 ◽

Vol 8 (1) ◽

pp. 61-66 ◽

Cited By ~ 5

Author(s):

P. Kapalo ◽

F. Domniţa ◽

C. Bacoţiu ◽

Nadija Spodyniuk

Keyword(s):

Carbon Dioxide ◽

Human Health ◽

Indoor Air ◽

Indoor Environment ◽

Carbon Dioxide Concentration ◽

Carbon Dioxide Production ◽

Human Respiration ◽

Office Rooms ◽

The Impact

Abstract From various other studies, it is known that the maximum carbon dioxide concentration in different countries is between 1,000 ppm up to 1,500 ppm. Therefore, the research is focused on indoor environment, namely the production of pollutants from the persons inside office rooms. The article presents the trend of the carbon dioxide concentration from the occupants inside an office. It is examined the carbon dioxide production separately for men and women, for persons of different mass and for persons of different ages. It is also analyzed the carbon dioxide production during a sedentary and physical activities. In parallel with the production of carbon dioxide is presented the monitoring of the human pulse and blood pressure. All these parameters are monitored together with relative humidity and indoor air temperature. The aims of this paper is to describe the partial results of human respiration impact on indoor air quality in closed spaces and to research the connection between carbon dioxide concentration and human health.

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Comparison of Effects of Ventilation, Filtration, and Outdoor Air on Indoor Air at Telephone Office Buildings: A Case Study

Design and Protocol for Monitoring Indoor Air Quality ◽

10.1520/stp10142s ◽

2008 ◽

pp. 9-9-26 ◽

Cited By ~ 4

Author(s):

CJ Weschler ◽

HC Shields ◽

SP Kelty ◽

LA Psota-Kelty ◽

JD Sinclair

Keyword(s):

Indoor Air ◽

Office Buildings ◽

Outdoor Air

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A Case Study on Indoor Comfort of Lecture Rooms in University Buildings

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.393.821 ◽

2013 ◽

Vol 393 ◽

pp. 821-826

Author(s):

H.A. Harun ◽

Norsheila Buyamin ◽

Mohamad Asyraf Othman ◽

Shaharin Anwar Sulaiman

Keyword(s):

Relative Humidity ◽

Indoor Air ◽

Indoor Environment ◽

Comfort Level ◽

Learning Ability ◽

University Buildings ◽

Ventilation Rates ◽

Indoor Comfort ◽

Recommended Level

The indoor environment of lecture rooms in universities can affect the learning of students. Nevertheless, study on the actual conditions of air in relation to indoor air quality is rare. This paper presents a case study on the indoor comfort of selected lecture rooms in a university. Two rooms of different sizes and ventilation rates were selected, in which the indoors air temperature, CO2 content and relative humidity were measured both when occupied and unoccupied. The study revealed that occupancy by students did not directly affect the relative humidity in the lecture rooms, probably due to the dominating influence of the outdoor air. It was found from the study that under high occupancy, the room temperature and CO2 content would be higher than the recommended level and thus affected the comfort level of students and consequently their learning ability during the lecture.

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