Massey Research Online - Browsing by Author "Boulic M"

Browsing by Author "Boulic M"

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Experimental Performance of a Solar Air Collector with a Perforated Back Plate in New Zealand
(MDPI AG, 18/03/2020) Wang Y; Boulic M; Phipps R; Plagmann M; Cunningham C
This study investigates the thermal efficiency of a solar air heater (SAH), when it was mounted on a custom-made support frame, and was operated under different air mass flow rate. This SAH is composed of a transparent polycarbonate cover plate, a felt absorber layer, a perforated aluminium back plate and an aluminium frame. The ambient inlet air of this SAH is heated as it passes through the perforated back plate and over the felt absorber layer. The heated air is blown out through the outlet. Studies of SAHs with a similar design to this SAH were not found in the literature. The experiment was carried out at Massey University, Auckland campus, NZ (36.7◦ S, 174.7◦ E). The global horizontal solar irradiance, the ambient temperature and the wind speed were recorded using an on-site weather station. Temperature and velocity of the air at the outlet were measured using a hot wire anemometer. During the experiment, the air mass flow rate was between 0.022 ± 0.001 kg/s and 0.056 ± 0.005 kg/s. Results showed that when the SAH was operated at the airflow between 0.0054 kg/s and 0.0058 kg/s, the inlet air temperature and the wind speed (between 0 and 6.0 m/s) did not impact the temperature difference between the outlet air and the inlet air. The thermal efficiency of the SAH increased from 34 ± 5% at the airflow between 0.021 kg/s and 0.023 kg/s, to 47 ± 6% at the airflow ranging from 0.032 kg/s to 0.038 kg/s, to 71 ± 4% at the airflow of 0.056 ± 0.005 kg/s. The maximum thermal efficiency of 75% was obtained at the airflow of 0.057 kg/s. The effective efficiency of the SAH was 32 ± 5% at the airflow between 0.021 kg/s and 0.023 kg/s, 42 ± 6% at the airflow ranging from 0.032 kg/s to 0.038 kg/s, and 46 ± 11% at the airflow of 0.056 ± 0.005 kg/s.
Gender-perceived workplace stressors by New Zealand construction professionals
(Taylor and Francis Group, 2024-02-19) van Heerden A; Boulic M; McDonald BW; Chawynski G
The construction workplace is male-dominated and stressful, but little is known about gender-based differences in its stressors. This research examined the effect of gender and personal attributes on stressors in the New Zealand construction industry at four major levels: (1) individual, (2) group, (3) organizational, and (4) extra-organizational. Target respondents were professional construction members from Site Safe New Zealand, with 317 completed questionnaires and statistical analysis using the two-sample t-test, Kruskal-Wallis test, and Levene’s test. The findings show that females have higher qualifications than males, but males have about ten years more experience and more completed projects than their female counterparts. Males reported significantly higher technical skills than females and there was no significant difference between genders regarding sector involvement. At the individual level, females were most affected by role conflict stress and the perception of different treatment because of gender. Males felt significantly higher stress over the variable 'on/off-site office/administration building conditions’. At the group level, there were no significant gender differences, but sexual harassment warranted further investigation. Within the organizational and extra-organizational levels, no variables differed significantly between genders. The construction workforce has a strong gender imbalance and efforts are needed to address this through better work-life balance.
He Kāinga Oranga: reflections on 25 years of measuring the improved health, wellbeing and sustainability of healthier housing
(Taylor and Francis, on behalf of Te Aparangi, The Royal Society of New Zealand, 2023-02-06) Howden-Chapman P; Crane J; Keall M; Pierse N; Baker MG; Cunningham C; Amore K; Aspinall C; Bennett J; Bierre S; Boulic M; Chapman R; Chisholm E; Davies C; Fougere G; Fraser B; Fyfe C; Grant L; Grimes A; Halley C; Logan-Riley A; Nathan K; Olin C; Ombler J; O’Sullivan K; Pehi T; Penny G; Phipps R; Plagman M; Randal E; Riggs L; Robson B; Ruru J; Shaw C; Schrader B; Teariki MA; Telfar Barnard L; Tiatia R; Toy-Cronin B; Tupara H; Viggers H; Wall T; Wilkie M; Woodward A; Zhang W
This paper reflects on the influences and outcomes of He Kāinga Oranga/Housing and Health Research Programme over 25 years, and their impact on housing and health policy in Aotearoa and internationally. Working in partnership particularly with Māori and Pasifika communities, we have conducted randomised control trials which have shown the health and broad co-benefits of retrofitted insulation, heating and remediation of home hazards, which have underpinned government policy in the Warm Up NZ-Heat Smart programme and the Healthy Homes Standards for rental housing. These trials have been included as evidence in the WHO Housing and Health Guidelines and led to our designation as a WHO Collaborating Centre on Housing and Wellbeing. We are increasingly explicitly weaving Māori frameworks, values and processes with traditional Western science.
Heater choice, dampness and mould growth in 26 New Zealand homes: A study of propensity for mould growth using encapsulated fungal spores
(MDPI AG, 2015) Boulic M; Phipps RA; Cunningham MJ; Cleland DJ; Fjallstrom P; Keiko P; Howden-Champan P
The relationship between the use of unflued gas heaters (UGH, N = 14) and heat pump heaters (HP, N = 12) located in the living rooms, and mould growth on the living room and bedroom walls, of 26 New Zealand (NZ) occupied homes was investigated during winter. Two methods were employed to evaluate the potential of mould growth on walls: (i) measurement of daily hyphal growth rate using a fungal detector (encapsulated fungal spores); and (ii) estimation of fungal contamination based on a four level scale visual inspection. The average wall psychrometric conditions were significantly different between the two heater type groups, in both the living rooms and the bedrooms with the UGH user homes being colder and damper than HP user homes. The UGHs were found to be a significant additional source of moisture in the living rooms which dramatically increased the capacity for fungi to grow on wall surfaces. The average daily hyphal growth rates were 4 and 16 times higher in the living rooms and in the bedrooms of the UGH user homes, respectively. Results from both mould detection methods gave good agreement, showing that the use of a fungal detector was an efficient method to predict the potential of mould growth on the inside of the external walls in NZ homes.
Retrofitting solar air heaters in New Zealand schools – A randomized crossover intervention study
(Elsevier B.V, 2024-06-15) Wang Y; Phipps R; Boulic M; Plagmann M; Cunningham C; Guyot G
Most New Zealand (NZ) schools rely on natural ventilation and are often inadequately ventilated in winter. NZ school hours typically span from 9 a.m. to 3 p.m. and are well aligned with optimum solar radiation. Existing classrooms could therefore be heated and ventilated using retrofitted solar energy applications. To investigate the suitability of a commercially available solar air heater (SAH) to improve ventilation, a randomized crossover intervention study was conducted in 12 classrooms from six primary schools in Palmerston North, NZ, during the winter of 2014. Typical performance results showed a mean (standard deviation, SD) SAH outlet air temperature of 29.2 (10.4) °C at a mean (SD) velocity of 0.7 (0.3) m·s-1. During most school periods (64–99%) classrooms maintained required thermal comfort. The concurrent use of the extant heaters was reduced, and carbon dioxide levels were improved, lowering exposure for occupants. This study confirmed that retrofitting SAHs contributed to improved classroom ventilation, increased thermal comfort and reduced energy use. Optimising performance would require design improvements to improve airflow in order to comply with NZ ventilation and indoor air quality requirements for schools.
Review of the thermal efficiency of a tube-type solar air heaters
(Elsevier B.V., 2024-05-11) Pardeshi PS; Boulic M; van Heerden AH; Phipps R; Cunningham CW
There is an urgent need to provide evidence that solar air heaters can be effective for heating and ventilating low-rise buildings. Solar air heaters are devices that can convert solar energy into thermal energy for moderate and low-temperature applications such as space heating, preheating, crop drying, and the food industry. However, its efficiency is low due to the low heat transfer coefficient between the absorber and the flowing air, but they are also simple to construct and operate as there is low-risk leakage of heat transfer liquids. The two main types of solar air heaters are flat plate and tube-type. To date, flat plate solar air heaters have received the most attention in the research literature, but evidence of the efficiency gains from using tube-type solar air heaters is growing. The study aims to provide up-to-date information on tube-type solar air heaters, which will help advance the development and uptake of solar air heaters. The research showed that thermal efficiency gains could be achieved by altering the design of the solar air heater including different artificial roughness geometries inside the tubes, integrating solar thermal energy systems, application of coatings or reflectors inside the solar air heaters, or using evacuated tubes and micro heat pipe array systems. This literature study showed that evacuated tubes and micro heat pipe array systems have higher thermal efficiency than other techniques. Based on the detailed discussion of various techniques for improving the thermal efficiency of solar air heaters, a new roughness geometry was proposed.
The built environment - A missing ‘cause of the causes’ of non- communicable diseases
(MDPI AG, 2016) Walls K; Boulic M; Boddy JWD
The United Nations “25 × 25 Strategy” of decreasing non-communicable diseases (NCDs), including cardiovascular diseases, diabetes, cancer and chronic respiratory diseases, by 25% by 2025 does not appear to take into account all causes of NCDs. Its focus is on a few diseases, which are often linked with life-style factors with “voluntary” “modifiable behavioral risk factors” causes tending towards an over-simplification of the issues. We propose to add some aspects of our built environment related to hazardous building materials, and detailed form of the construction of infrastructure and buildings, which we think are some of the missing causes of NCDs. Some of these could be termed “involuntary causes”, as they relate to factors that are beyond the control of the general public.
Using trickle ventilators coupled to fan extractor to achieve a suitable airflow rate in an Australian apartment: A nodal network approach connected to a CFD approach
(Elsevier B.V., 2023-12-26) Boulic M; Bombardier P; Zaidi Z; Russell A; Waters D; van Heerden A
The level of airtightness is increasing in newly built Australian apartments. Due to the COVID-19 pandemic, restrictions have forced many people to work from home. An appropriate ventilation rate is needed to decrease virus transmission and provide occupants with a healthy environment. As occupants tend not to open windows, they need to be informed about the potential benefit of using trickle ventilators, in connection with exhaust systems, to ventilate their apartments. In 2022, a provision for lower rates of continuous ventilation (10 L.s−1 for the bathroom exhaust system and 12 L.s−1 for the kitchen exhaust system) was considered for inclusion in the National Construction Code of Australia. This provision was not adopted; however, this is still a valid reference for good practice. Based on this provision for continuous ventilation, our study aims to investigate the airflow velocity and the ventilation efficiency to remove the carbon dioxide (CO2) generated across winter and summer seasons in a Melbourne apartment occupied by two adults and a child over four hours. The study's objectives are 1) to connect two modelling approaches (Computational Fluid Dynamics and nodal networks), and 2) to investigate the potential benefits of using trickle ventilators across winter and summer seasons. The results show that wind conditions have limited effects (4% decrease in the extracted air flow rate) if the extraction network output is protected from the wind. Comparing winter and summer conditions, we found that indoor airflows differed, highly influenced by the temperature difference between outside and inside. We observed that the airflow patterns were more inclined to create “CO2 pockets” during winter, which could increase virus transmission due to ineffective ventilation in this area. However, in winter, ventilation performed better in reducing the CO2 concentration in the kitchen/living room area and the whole apartment than it did during summer.
Validation of low-cost air quality monitoring platforms using model-based control charts
(Elsevier Ltd, 2024-04-01) Boulic M; Phipps R; Wang Y; Vignes M; Adegoke NA
The SARS COVID-19 pandemic highlighted the importance of routine indoor air quality (IAQ) monitoring. Recent advances in IAQ sensors and remote logging technologies offer opportunities to use low-cost platforms to monitor indoor air. The sensor's accuracy and stability are critical for reliable monitoring and health protection. Data from our low-cost IAQ platform (SKOMOBO) was validated against a commercial platform for carbon dioxide, temperature, and relative humidity measurements to test the reliability of the low-cost instrument. The traditional statistical method to test the variability between two data sets is the coefficient of determination method. We identified that this traditional method did not detect drifts in measurements, when comparing data from two platforms, in a controlled and uncontrolled environment. In our paper, we propose two complementary methods to detect potential drifts in measurements (a modified Shewhart method and a cumulative sum control chart method). The traditional coefficient of determination method indicated strong consistency (between 0.70 and 0.99) in the measurements between SKOMOBO and the reference platforms for both tested environments. Our more sensitive methods detected 100 % data matching for the controlled environment between the SKOMOBO and the reference platform but detected some drifts for the uncontrolled environment (between 81 % and 100 % data matching). It was expected that the uncontrolled environment would create more drifts in measurements than the controlled environment. Our new statistical methods achieved two important results; namely it advanced the validation process and proved the reliability of our low-cost platform for IAQ monitoring and assurance.

Browsing by Author "Boulic M"

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