Detection of Suspended SARS-CoV-2 in Indoor Air Using an Electrostatic Sampler

A prototype virus sampler using electrostatic precipitation has been developed to investigate aerosol infection by SARS-CoV-2. The sampler consists of a discharge electrode placed inside a vial, and a thin layer of viral lysis buffer at the bottom, working as a collection electrode. The sampler was operated with the sampling air flow rate of 40 L/min. Collection efficiency of the sampler is about 80% for 25nm to 5.0µm diameter particles. We sampled the air of a food court of a commercial facility, a connecting corridor of a clouded train station, and two office rooms (A and B) in September 2021, just after the 5th peak of COVID-19 in Japan. The analysis using a RT-qPCR detected the virus RNA in the air of the office A, B and the food court. Estimated concentration of the virus in the air determined by calibration curve was 2.0 x 102, 7.8 x 102, and 0.6 - 2.4 x 102 copies/m3, in the office A, B, and the food court, respectively. These results indicate that the sampler using electrostatic precipitation can detect SARS-CoV-2 in indoor air. It could be developed as a risk assessment method for aerosol infection.

Study on the Effect of an Intermittent Ventilation Strategy on Controlling Formaldehyde Concentrations in Office Rooms

Material emission and ventilation are two aspects influencing indoor air quality. In this study, a model predictive control (MPC) strategy is proposed for intermittent ventilation system in office buildings, to achieve a healthy indoor environment. The strategy is based on a dynamic model for predicting emissions of volatile organic compounds (VOCs) from materials. The key parameters of formaldehyde from panel furniture in the model are obtained by an improved C-history method and large-scale chamber experiments. The effectiveness of the determined key parameters is validated, which are then used to predict the formaldehyde concentration variation and the pre-ventilation time in a typical office room. In addition, the influence of some main factors (i.e., vacant time, loading ratio, air change rate) on the pre-ventilation time is analyzed. Results indicate that the pre-ventilation time of the intermittent ventilation system ranges from several minutes to several hours. The pre-ventilation time decreases exponentially with the increase in the vacant time, the air change rate, and with the decrease in the loading ratio. When the loading ratio of the furniture is 0.30 m2/m3 and the vacant time is 100 days, the required pre-ventilation time approaches zero. Results further reveal that an air change rate of 2 h−1 is the most effective means for rapid removal of indoor formaldehyde for the cases studied. The proposed strategy should be helpful for achieving effective indoor pollution control.

Analysis of Office Rooms Energy Consumption Data in Respect to Meteorological and Direct Sun Exposure Conditions

There are many papers concerning the consumption of energy in different buildings. Most describe residential buildings, with only a few about office- or public service buildings. Few articles showcase the use of energy consumption in specific rooms of a building, directed in different geographical directions. On the other hand, many publications present methods, such as machine learning or AI, for building energy management and prediction of its consumption. These methods have limitations and represent a certain level of uncertainty. In order to compare energy consumption of different rooms, the measurements of particular building-room parameters were collected and analyzed. The obtained results showcase the effect of room location, regarding geographical directions, for the consumption of energy for heating. For south-exposed rooms, due to sun radiation, it is possible to switch heating off completely, and even overheating of 3 °C above the 22 °C temperature set point occurs. The impact of the sun radiation for rooms with a window directed east or west reached about 1 °C and lasts for a few hours before noon for the east, and until late afternoon for the west.

Evaluation of air quality in office rooms (case study: the rector’s office building of Syiah Kuala University)

The Rector’s Office Building of Syiah Kuala University is the administrative headquarters at Syiah Kuala University which has a high density schedule. Employees in the building, work for 8 hours a day in the building. Staying in a room for an extended period of time can lead to disease, particularly Sick Building Syndrome (SBS). Poor air quality as a result of air pollution and poor air exchange is the primary cause of SBS. Therefore, it is important to evaluate the air quality in the room to prevent SBS. This research was conducted with a quantitative approach by measuring the physical and chemical quality of the indoor air. The study was conducted on two sample rooms, namely the administration room and the student affairs office. The method of collecting data is descriptive by evaluating based on the regulations of the minister of health and SNI. Air quality is also seen based on the results of room simulations using ANSYS 2019 R3. Based on the results of field measurements, the air quality in the room is not good. Thus, 60% of the employees in the Administration Room and 64.71% of the employees in the Student Affairs Office were infected with SBS.

Impact of Phase Change Material (PCM) glazing on the energy consumption and solar radiation transmission in an office room located in a semi-arid climate: Analysis of a real-scale experiment

Phase Change Materials (PCMs) are materials with high latent heat. When integrated into the glazing, they arise as an innovative strategy to improve thermal performance and provide thermal inertia in office buildings with a lack of opaque. Climates with high solar radiation and great temperature variation between day and night are especially interesting because PCM glazing can vastly improve these buildings’ energy performance. Then, this paper aims to analyze the energy performance of an office room with PCM glazing compared to a reference room with double-clear glazing, in a semi-arid climate. A real-scale experiment was carried out for a year in two office rooms located in Santiago, Chile. The analyses include energy consumption of the HVAC system to keep the interior temperature of the room in the comfort range and the solar radiation transmitted through the windows. Results are presented for three representative weeks of summer, mid-season and winter. An important reduction of the solar radiation transmitted was achieved in the PCM glazing in respect to the double-clear glazing when the phase change occurs, and a decrease of the energy consumption of cooling and heating mainly for sunny and variable days was found.

Data-driven occupant-centric rules of automated shade adjustments: Luxembourg case study

This study presents key findings of observed datasets in a nearly zero-energy office building for over 66 working days from June to mid-September in 2019, Luxembourg. Measurements of indoor and outdoor environmental parameters as well as user-shade override adjustments were extracted from the KNX-based building management system (BMS) in 47 office rooms located in three typical floor levels. Relative frequency and “rate of change” of blind use were analysed in terms of window orientation, occupancy level, and the time of the day. Logistic regression and data mining techniques were used to identify potentially useful and understandable occupant behaviour patterns and reveal the main triggers behind blind adjustments. The well-designed automation system together with the inner glare protection formed the base of very low user-shade interactions. A mean of 0.184 manual blind adjustments per day per office. Eight regression sub-models were developed and all were incapable of predicting user-shade lowering and raising events. Alternatively, two user profiles were mined based on 20 rules gained from clustering analysis: user (ß) was representing the passive user, and user (μ) the medium user. Overall, we conclude that the automated shading system in this building is satisfactory, user-friendly, and a robust control system.

Automatic Room Lights Controller Using Arduino and PIR Sensor

Automatic room lights controller can be installed in which the room lights will turn on automatically upon detection of human motion and will stay tuned until the motion stops or the person has left the room. Such type of system can be implemented where we don’t require continuous light supply but only when a person is present. The common places where we can install the system are washrooms, bathrooms, office rooms, classrooms in schools and colleges, garages, etc. Also, using this controller system, we don’t need to worry about electricity as the room lights will switch off on their own when no person is present. A huge amount of energy and economy will also be saved . The main components of the Automatic Room Lights project are Arduino Uno, PIR Sensor and the Relay Module. Keywords: Arduino Uno, Lights, PIR sensor, Relay Module

Exploring Cross-Modal Influences on the Evaluation of Indoor-Environmental Conditions

The comfort requirements of occupants influence indoor-environmental factors and energy performance of buildings. Occupants are typically exposed to a multitude of indoor-environmental factors, including a variety of different thermal, auditory, visual, and air quality conditions. However, the bulk of past research and derivative indoor-environmental codes and standards concerning the comfort of occupants address the multiple indoor-environmental stimuli in isolation. Starting from a brief review of past research on multi-perceptual indoor-environmental assessments of occupants, the present study pursues an experimental approach to explore the potential cross-modal effects on the evaluation of indoor-environmental thermal, visual, and acoustic aspects. In this context, a laboratory space including two adjacent identical mock-up office rooms was used to conduct multi-aspect parametric studies with human participants. Different thermal, visual, and auditory conditions were maintained in these two units. In the course of the present study, 296 participants were exposed, on a short-term basis, to different combinations of thermal, visual, and auditory conditions. The experiments were intended to explore if the evaluation of one aspect of the indoor environment could be influenced by differences in the values pertaining to the other aspects. The experimental results are presented and discussed, including their limitations.