Experimental investigation of ventilation efficiency in a dentistry surgical room

As a response to the need to provide an acceptable thermal comfort and air quality in indoor environments, various ventilation performance indicators were developed over the years. These metrics are mainly geared towards air distribution, heat and pollutant removals. Evidence exists of influencing factors on these indicators as centered on ventilation design and operations. Unlike other indoor environments, health care environment requires better performance of ventilation system to prevent an incidence of nosocomial and other hospital acquired illnesses. This study investigates, using in-situ experiments, the ventilation efficiency in a dentistry surgical room. Thermal and hygric parameters were monitored on the air terminal devices and occupied zone over a period of one week covering both occupied and unoccupied hours. The resulting time-series parameters were used to evaluate the room's ventilation effectiveness. Also, the obtained parameters were benchmarked against ASHRAE 170 (2013) and MS1525 (2014) requirements for ventilation in health care environment and building energy efficiency respectively. The results show that the mean daily operative conditions failed to satisfy the provisions of both standards. Regarding effectiveness, the findings reveal that the surgical room ventilation is ineffective with ventilation efficiency values ranging between 0 and 0.5 indicating air distribution short-circuiting. These results suggest further investigations, through numerical simulation, on the effect of this short-circuiting on thermal comfort, infection risk assessments and possible design improvements, an endeavour that forms our next line of research inquiries

Cost effectiveness of ward based non-invasive ventilation for acute exacerbations of chronic obstructive pulmonary disease: economic analysis of randomised controlled trial

OBJECTIVE: To evaluate the cost effectiveness of standard treatment with and without the addition of ward based non-invasive ventilation in patients admitted to hospital with an acute exacerbation of chronic obstructive pulmonary disease. DESIGN: Incremental cost effectiveness analysis of a randomised controlled trial. SETTING: Medical wards in 14 hospitals in the United Kingdom. PARTICIPANTS: The trial comprised 236 patients admitted to hospital with an acute exacerbation of chronic obstructive pulmonary disease and mild to moderate acidosis (pH 7.25-7.35) secondary to respiratory failure. The economic analysis compared the costs of treatment that these patients received after randomisation. MAIN OUTCOME MEASURE: Incremental cost per in-hospital death. RESULTS: 24/118 died in the group receiving standard treatment and 12/118 in the group receiving non-invasive ventilation (P=0.05). Allocation to the group receiving non-invasive ventilation was associated with a reduction in costs of £49 362 ($78 741; 73 109), mainly through reduced use of intensive care units. The incremental cost effectiveness ratio was £645 per death avoided (95% confidence interval £2310 to £386), indicating a dominant (more effective and less costly) strategy. Modelling of these data indicates that a typical UK hospital providing a non-invasive ventilation service will avoid six deaths and three to nine admissions to intensive care units per year, with an associated cost reduction of £12 000-53 000 per year. CONCLUSIONS: Non-invasive ventilation is a highly cost effective treatment that both reduced total costs and improved mortality in hospital

Useful energy transfer in air-to-air heat recovery units in partly heated low energy buildings

In this study, the performance of ventilation systems with heat recovery in residential buildings with a low energy demand for heating was evaluated. In a completely heated building, the percentage of useful recovered heat will be equal to the nominal effectiveness of the heat exchanger. In the case some rooms are not heated, they will still receive preheated air. This part of the recovered heat will not directly increase comfort, so it does not completely contribute to the energy savings of the building. Simulations were done with TRNSYS to assess the percentage of usefully recovered heat. This value was found to be lower than the nominal effectiveness, but varying with several parameters

High-Performance Integrated Window and Façade Solutions for California

The researchers developed a new generation of high-performance façade systems and supporting design and management tools to support industry in meeting California’s greenhouse gas reduction targets, reduce energy consumption, and enable an adaptable response to minimize real-time demands on the electricity grid. The project resulted in five outcomes: (1) The research team developed an R-5, 1-inch thick, triplepane, insulating glass unit with a novel low-conductance aluminum frame. This technology can help significantly reduce residential cooling and heating loads, particularly during the evening. (2) The team developed a prototype of a windowintegrated local ventilation and energy recovery device that provides clean, dry fresh air through the façade with minimal energy requirements. (3) A daylight-redirecting louver system was prototyped to redirect sunlight 15–40 feet from the window. Simulations estimated that lighting energy use could be reduced by 35–54 percent without glare. (4) A control system incorporating physics-based equations and a mathematical solver was prototyped and field tested to demonstrate feasibility. Simulations estimated that total electricity costs could be reduced by 9-28 percent on sunny summer days through adaptive control of operable shading and daylighting components and the thermostat compared to state-of-the-art automatic façade controls in commercial building perimeter zones. (5) Supporting models and tools needed by industry for technology R&D and market transformation activities were validated. Attaining California’s clean energy goals require making a fundamental shift from today’s ad-hoc assemblages of static components to turnkey, intelligent, responsive, integrated building façade systems. These systems offered significant reductions in energy use, peak demand, and operating cost in California

Modelling the air cleaning performance of negative air ionisers in ventilated rooms

Negative air ionisers have seen increasing use as devices for improving indoor air quality, including some success in clinical environments for reducing the transmission of infection. This study uses a ventilation model and a CFD model to examine the physical effects of negative ionisers in indoor environments. The results demonstrate how the negative ion distribution and electric field due to an ioniser are influenced by both the room airflow and the ion generation rate. It is shown that ion concentrations greater than 1010 ions/m3 are necessary for the electrical effects to be significant. The effect on particles is also considered, with the results demonstrating that the ioniser will only increase the deposition of particles when the particle concentration is high enough to contribute to the space charge in the room

Penguasaan kemahiran komunikasi interpersonal dalam kalangan pelajar tahun satu Fakulti Pendidikan Teknikal dan Vokasional di UTHM

Terdapat pelbagai kerangka pembangunan dan pendekatan yang boleh dilaksanakan oleh IPT dalam usaha untuk membangunkan kemahiran generik dalam kalangan pelajar antaranya adalah pembangunan kemahiran generik melalui aktiviti formal pengajaran dan pembelajaran, berasaskan program sokongan dan berasaskan kehidupan di kampus. Kajian ini dilaksanakan untuk mengenal pasti kemahiran komunikasi interpersonal pelajar dalam pembelajaran yang merangkumi aspek komunikasi lisan, komunikasi bukan lisan, kemahiran berucap, kemahiran mendengar, kemahiran maklum balas dan kemahiran menulis maklumat di universiti melibatkan seramai 74 orang responden dari pelajar tahun satu program Sarjana Pendidikan Teknik dan Vokasional di Universiti Tun Hussein Onn. Metodologi yang dijalankan adalah berbentuk deskriptif dan inferensi menggunakan instrumen soal selidik dengan skala lima mata. Nilai pekali Alpha Cronbach untuk kajian ini adalah 0.937. Perisian yang digunakan untuk melakukan analisis kajian ialah SPSS versi 16.0. Hasil analisis mendapati aspek komunikasi lisan mencatatkan nilai bacaan skor min yang tinggi iaitu sebanyak 4.01 manakala komunikasi bukan lisan mencatatkan nilai bacaan skor min sebanyak 3.82. Aspek kemahiran komunikasi lain juga mencatatkan skor min yang tinggi iaitu kemahiran ucapan mempunyai nilai sebanyak 3.91, kemahiran mendengar sebanyak 4.03, kemahiran maklum balas sebanyak 3.92 dan kemahiran menulis maklumat mencatatkan nilai skor min sebanyak 4.02. Secara keseluruhannya, tahap kemahiran komunikasi interpersonal pelajar berada pada tahap yang tinggi dan hasil kajian juga mendapati wujud perbezaan yang signifikan penguasaan kemahiran komunikasi interpersonal berdasarkan latar belakang pendidikan. Pada kajian akan datang, dicadangkan supaya mempelbagaikan instrumen kajian seperti secara temu duga dan kajian kes agar dapat melihat perbezaan di antara kedua-duanya

Airborne Particles in Museums

Presents one in a series of research activities aimed at a better understanding of the origin and fate of air pollution within the built environment

Nexus of thermal resilience and energy efficiency in buildings: A case study of a nursing home

Extreme weather events become more frequent and severe due to climate change. Although energy efficiency technologies can influence thermal resilience of buildings, they are traditionally studied separately, and their interconnections are rarely quantified. This study developed a methodology of modeling and analysis to provide insights into the nexus of thermal resilience and energy efficiency of buildings. We conducted a case study of a real nursing home in Florida, where 12 patients died during Hurricane Irma in 2017 due to HVAC system power loss, to understand and quantify how passive and active energy efficiency measures (EEMs) can improve thermal resilience to reduce heat-exposure risk of patients. Results show that passive measures of opening windows and doors for natural ventilation, as well as miscellaneous load reduction, are very effective in eliminating the extreme dangerous occasions. However, to maintain safe conditions, active measures such as on-site power generators and thermal storage are also needed. The nursing home was further studied by changing its location to two other cities: San Francisco (mild climate) and Chicago (cold winter and hot summer). Results revealed that the EEMs' impacts on thermal resilience vary significantly by climate and building characteristics. The study also estimated the costs of EEMs to help stakeholders prioritize the measures. Passive measures that may not save energy may greatly improve thermal resilience, and thus should be considered in building design or retrofit. Findings from this study indicate energy efficiency technologies should be evaluated not only by their energy savings performance but also by their influence on a building's resilience to extreme weather events

Modelling the air cleaning performance of negative air ionisers in ventilated rooms

Negative air ionisers have seen increasing use as devices for improving indoor air quality, including some success in clinical environments for reducing the transmission of infection. This study uses a ventilation model and a CFD model to examine the physical effects of negative ionisers in indoor environments. The results demonstrate how the negative ion distribution and electric field due to an ioniser are influenced by both the room airflow and the ion generation rate. It is shown that ion concentrations greater than 1010 ions/m3 are necessary for the electrical effects to be significant. The effect on particles is also considered, with the results demonstrating that the ioniser will only increase the deposition of particles when the particle concentration is high enough to contribute to the space charge in the room