Understanding occupancy pattern of university libraries in the post-pandemic era

Understanding indoor occupancy patterns is crucial for energy model calibration, efficient operations of fresh air systems, and COVID-19 exposure risk assessment. University libraries, as one of centers of campus life, due to the high mobility and "foot-voting” nature of them, i.e., occupants pick seats in the micro-environments they prefer, provide a non-intrusive opportunity to carry out post-occupancy evaluations. We conducted a long-term online monitoring of occupancy in libraries of a university in China by web-crawling the online seat reservation system, based on which, we constructed two sets of databases consisting of around 70 million records of nearly 3, 000 seats in 4 library sections, with seat-level resolution and sampling frequency up to every 10 seconds. The informative data set depicts not only the overall spatio-temporal occupancy patterns, but also nuances hidden within seats and visits. The daily flow of the main libraries exceeded two visits per seat. Half of the visitors stayed at the libraries for 3-6 hours during a single occupancy. Semester schedules and campus accessibility together influence students' decisions on when and which library to go, while even within the same zone, some seats were always more popular than their neighbours. "Semi-isolation” is one of the candidate attractive features proposed to understand the underlying patterns. © 2022 17th International Conference on Indoor Air Quality and Climate, INDOOR AIR 2022. All rights reserved.

Experimental and numerical evaluation of a novel dual-channel windcatcher with a rotary scoop for energy-saving technology integration

With the increasing requirements for fresh air supply in buildings after the COVID-19 pandemic and the rising energy demand from buildings, there has been an increased emphasis on passive cooling techniques such as natural ventilation. While natural ventilation devices such as windcatchers can be a sustainable and low-cost solution to remove indoor pollutants and improve indoor air quality, it is not as reliable as mechanical systems. Integration with low-energy cooling, heating or heat recovery technologies is necessary for operation in unfavourable outdoor conditions. In this research, a novel dual-channel windcatcher design consisting of a rotary wind scoop and a chimney was proposed to provide a fresh air supply irrespective of the wind direction. The dual-channel design allows for passive cooling, dehumidification and heat recovery technology integration to enhance its thermal performance. In this design, the positions of the supply and return duct are "fixed” or would not change under changing wind directions. An open wind tunnel and test room were employed to experimentally evaluate the ventilation performance of the proposed windcatcher prototype. A Computational Fluid Dynamic (CFD) model was developed and validated to further evaluate the system's ventilation performance. The results confirmed that the system could supply sufficient fresh air and exhaust stale air under changing wind directions. The ventilation rate of the rotary scoop windcatcher was higher than that of a conventional 8-sided multidirectional windcatcher of the same size. © 2023 The Author(s)

Copacabana Promenade: design as heritage

Fresh air became a luxury good in times of Covid-19 pandemic. After lockdowns' stringency is over, former enclosed activities have been adapted to be held in open air spaces, reinforcing the importance of well-designed parks, squares and sidewalks. This paper will address one of the most iconic Brazilian public open spaces: the Copacabana promenade, designed by Roberto Burle Marx. Extending 4,5 kilometers alongside Rio de Janeiro's waterfront, the three sidewalk lanes are a social living spot, housing multiple activities. Appealing to tradition, Burle Marx designed a Portuguese stone mosaic, but innovated by proposing modern and patterns. It is an exceptional case of heritage-valued public landscape combined with social appropriation and very intense use. Unfortunately, Copacabana promenade's integrity has been constantly threatened. Many pubs and restaurants extended their structures over the pavement, ruining both the sidewalk materiality and the landscape;a number of potholes denounce the lack of appropriate maintenance - even if both the stone mosaics and the vegetation designed by Burle Marx are listed as municipal and state heritage. The promenade is also included in the "culture landscape” of Rio de Janeiro, listed as a World Heritage by Unesco, in 2012, highlighted for its contribution to the outdoor living culture. The case of Copacabana Promenade suggests that not always is materiality the real heritage. In some cases - such as some landscape architectures - materiality renovation is a requirement to design conservation and the fundamental document to heritage preservation is the paper and not the stone. © Design: Social Commitment and Quality of Life, Proceedings.All rights reserved.

Study on Heating Performance of Solar Fresh Air Systems

Due to the global spread of COVID-19, indoor air quality has been paid more and more attention by many countries. However, the ventilation of buildings often causes a significant increment in buildings' heating and cooling load, especially in the winter of the Northern Hemisphere. Solar fresh air systems can provide heated fresh air to buildings on sunny days. This system can provide not only fresh air to buildings but also improve indoor air quality. At the same time, the heating load of buildings will be significantly decreased by the application of this new system. Solar fresh air systems can even take the existing heating energy source's place under high solar irradiation. The solar heating performance of the solar fresh air system is affected by many factors. The two most important factors are the structure of the solar heating panel and the performance of solar absorption coating on the solar heating panel. This research project has built three sets of real solar fresh air systems to test the influence of different solar absorption coatings and different solar heating panel structures on the heating performance of the solar fresh air system. This paper focuses on the test of stagnation performance and solar heating efficiency. © 2021. The Authors. Published by International Solar Energy Society Selection and/or peer review under responsibility of Scientific Committee.

How to Cover Additional Cooling Load Needs During COVID-19 Pandemic?

It has been crystal clear to everyone that the fresh air supply is one of the highest priorities to keep people under safe indoor conditions during the COVID-19 pandemic. In many buildings, either there are no mechanical ventilation systems or the air conditioning systems do not have adequate capacity to meet the additional cooling loads for the increased fresh air requirement. Providing fresh air without disturbing the thermal conditions in the building requires a substantially increased cooling load and operating costs. On the other hand, there may not be adequate power infrastructure to meet this additional energy demand item in many regions. In this technical brief paper, we aim to emphasize the importance of heat storage systems and provide a quick solution to illustrate that they can meet the fresh air demands without requiring additional chiller or chiller capacity. In addition, it is observed that heat storage systems can be a convenient solution to meet the urgent and additional cooling loads in a more sustainable way.

Analysis of the impact of a fresh air system on the indoor environment in office buildings.

This study conducted objective physical tests and subjective questionnaire surveys related to the operation of a fresh air system in an office building in Beijing before the outbreak of the coronavirus disease 2019 (COVID-19). The long-term tests on indoor environmental parameters included air temperature, relative air humidity, air velocity, CO2 concentration, PM2.5 concentration, and fresh air volume, and the questionnaire surveyed the satisfaction of office workers in the indoor environment. The results showed that the indoor environmental parameters conformed to the values specified in relevant design standards; however, the satisfaction with the indoor environmental parameters was generally low. The probability of infection of indoor personnel with the virus causing COVID-19 under two existing fresh air system operation modes was calculated and compared, and it was less than 5%. A gray correlation analysis of the measured data with the questionnaire results identified indoor air temperature and quality as the main factors affecting the subjective satisfaction, which was consistent with the results of the questionnaire analysis. A new operation and maintenance method for fresh air systems was proposed for regular epidemic prevention and control to ensure the normal operation of the office building and the health of indoor personnel.

Thermodynamic Analysis of Air-Cycle Refrigeration Systems with Expansion Work Recovery for Compartment Air Conditioning

As a requirement for sustainable development, air-cycle refrigeration has received wide attention as a candidate for environmentally friendly air conditioning technology. In this study, the thermodynamic performance of air refrigeration cycles is investigated in compartment air conditioning. The effects of compressor efficiency, expander efficiency, ambient humidity, all-fresh-air supply and ambient pressure on the cycle performance are presented. The effects of compressor arrangement in the high-pressure cycle and the low-pressure cycle are compared. An open-loop high-pressure cycle has a larger COP than that of an open-loop low-pressure cycle but requires larger heat exchange. The performance of air refrigeration cycles with full fresh air is studied, and the influence of fresh air is discussed. Schemes for condensed water recirculation with wet compression are proposed, which can improve the COPs of open-loop low-pressure cycles by 44.7%, 48.8% and 48.4%. In the air conditioning of plateau trains, open-loop high-pressure cycles have slightly lower COPs, but they can supply air with elevated pressure and oxygen concentration.

Designing and Simulating a Smart Air Purifier to Combat HVAC-induced COVID-19 Transmission

Although heating, ventilation, and air conditioning (HVAC) systems serve the important function of providing fresh air changes for indoor spaces, they have been shown to distribute aerosolized severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) across such spaces and potentially exacerbate the risk of coronavirus disease 2019 (COVID-19) transmission. This paper proposes a solution to this issue in the form of a distributed network of compact air purifier modules stationed on tables, to be implemented alongside an HVAC system. Each module would use a high efficiency particulate air filter to capture SARS-CoV-2 and an ultraviolet C light-emitting diode (UVC LED) to routinely sterilize the filter. The module's structure is outlined using Computer Aided Design, its Internet of Things networking capabilities are mapped out using microcontrollers and a mobile application, and its potential impacts are modeled using computational fluid dynamics (CFD) simulations. The module would capture at least 99.97% of SARS-CoV-2 particles it encounters, fully decontaminate its filter with 108.4s of UVC exposure, and treat potentially contaminated air before an HVAC system pushes such air to others by manipulating airflow. © 2020 IEEE.

Study on indoor air quality and fresh air energy consumption under different ventilation modes in 24-hour occupied bedrooms in Nanjing, using Modelica-based simulation.

COVID-19 has forced people to spend more time working and studying at home; in particular, people who share an apartment stay in their respective bedrooms almost all day. This study investigated the impact of ventilation modes on the indoor air quality (IAQ) of 24-hour occupied bedrooms and provided ventilation suggestions for people who stay in their bedrooms for a long time during the pandemic compared with the study of traditional apartment ventilation. In addition, the fresh air energy consumption of different ventilation modes was compared to help residents save energy. In summer, a window-opening ratio of 25% (0.3 m2) could effectively improve IAQ. However, it is not recommended to use natural ventilation in winter because the outdoor PM2.5 concentration is too high. Moreover, the fresh air energy consumption for the automatic control window-opening ratio was 1/5 of that for a window-opening ratio of 25%. In the whole summer, it can save 196.1 kW·h compared to a fixed window-opening ratio of 25%. Fresh air systems could greatly improve IAQ and lower energy consumption regardless of the season. However, the automatic-control window-opening ratio mode has lower energy consumption, which is approximately 0.37 times that of fresh air systems in summer.

COVID 19 vaccine distribution solution to the last mile challenge: Experimental and simulation studies of ultra-low temperature refrigeration system.

Most COVID-19 vaccines require ambient temperature control for transportation and storage. Both Pfizer and Moderna vaccines are based on mRNA and lipid nanoparticles requiring low temperature storage. The Pfizer vaccine requires ultra-low temperature storage (between -80 °C and -60 °C), while the Moderna vaccine requires -30 °C storage. Pfizer has designed a reusable package for transportation and storage that can keep the vaccine at the target temperature for 10 days. However, the last stage of distribution is quite challenging, especially for rural or suburban areas, where local towns, pharmacy chains and hospitals may not have the infrastructure required to store the vaccine. Also, the need for a large amount of ultra-low temperature refrigeration equipment in a short time period creates tremendous pressure on the equipment suppliers. In addition, there is limited data available to address ancillary challenges of the distribution framework for both transportation and storage stages. As such, there is a need for a quick, effective, secure, and safe solution to mitigate the challenges faced by vaccine distribution logistics. The study proposes an effective, secure, and safe ultra-low temperature refrigeration solution to resolve the vaccine distribution last mile challenge. The approach is to utilize commercially available products, such as refrigeration container units, and retrofit them to meet the vaccine storage temperature requirement. Both experimental and simulation studies are conducted to evaluate the technical merits of this solution with the ability to control temperature at -30 °C or -70 °C as part of the last mile supply chain for vaccine candidates.

Reducing Morbidity and Mortality Rates from COVID-19, Influenza and Pneumococcal Illness in Nursing Homes and Long-Term Care Facilities by Vaccination and Comprehensive Infection Control Interventions.

The COVID-19 pandemic identifies the problems of preventing respiratory illnesses in seniors, especially frail multimorbidity seniors in nursing homes and Long-Term Care Facilities (LCTFs). Medline and Embase were searched for nursing homes, long-term care facilities, respiratory tract infections, disease transmission, infection control, mortality, systematic reviews and meta-analyses. For seniors, there is strong evidence to vaccinate against influenza, SARS-CoV-2 and pneumococcal disease, and evidence is awaited for effectiveness against COVID-19 variants and when to revaccinate. There is strong evidence to promptly introduce comprehensive infection control interventions in LCFTs: no admissions from inpatient wards with COVID-19 patients; quarantine and monitor new admissions in single-patient rooms; screen residents, staff and visitors daily for temperature and symptoms; and staff work in only one home. Depending on the vaccination situation and the current risk situation, visiting restrictions and meals in the residents' own rooms may be necessary, and reduce crowding with individual patient rooms. Regional LTCF administrators should closely monitor and provide staff and PPE resources. The CDC COVID-19 tool measures 33 infection control indicators. Hand washing, social distancing, PPE (gowns, gloves, masks, eye protection), enhanced cleaning of rooms and high-touch surfaces need comprehensive implementation while awaiting more studies at low risk of bias. Individual ventilation with HEPA filters for all patient and common rooms and hallways is needed.