title: Share an idea: AI-augmented urban narrative

authors: Dyer, Mark

subjects: computer science

abstract: Many lessons were learnt from Christchurch City Council's attempt to empower local citizens to co-design the redevelopment of the city centre following the devastating events of a series of major earthquakes between 2011 and 2012. Running against the grain of national politics, the grassroots public consultation exercise was largely over-ridden by the central government's decision to hand over final responsibility for rebuilding of the city to the Canterbury Earthquake Recovery Authority (CERA). Predictably, the centrally administered bureaucratic process attracted considerable criticism with studies indicating that CERA was ill-equipped and unwilling to engage effectively with the public, which resulted in predictably poor public perceptions. The outcome pointed towards the need for greater clarity about the willingness or otherwise of public agencies or government to share decision making before public engagement to avoid disappointment and disillusionment. Without which, the perception of power-sharing becomes an illusion that can quickly turn into public dissatisfaction with public authorities. Furthermore, the problem arose in part due to a focus on solutions rather than prioritising user needs underpinned by shared culture values. To overcome future political impasses between local and national government agencies, an alternative method of collecting and analysing data from public consultation is proposed using AI where large volumes of public data can be readily processed to communicate shared narratives about shared values for future public works such as the rebuild of Christchurch.

text: Share an idea: AI-augmented urban narrative Many lessons were learnt from Christchurch City Council's attempt to empower local citizens to co-design the redevelopment of the city centre following the devastating events of a series of major earthquakes between 2011 and 2012. Running against the grain of national politics, the grassroots public consultation exercise was largely over-ridden by the central government's decision to hand over final responsibility for rebuilding of the city to the Canterbury Earthquake Recovery Authority (CERA). Predictably, the centrally administered bureaucratic process attracted considerable criticism with studies indicating that CERA was ill-equipped and unwilling to engage effectively with the public, which resulted in predictably poor public perceptions. The outcome pointed towards the need for greater clarity about the willingness or otherwise of public agencies or government to share decision making before public engagement to avoid disappointment and disillusionment. Without which, the perception of power-sharing becomes an illusion that can quickly turn into public dissatisfaction with public authorities. Furthermore, the problem arose in part due to a focus on solutions rather than prioritising user needs underpinned by shared culture values. To overcome future political impasses between local and national government agencies, an alternative method of collecting and analysing data from public consultation is proposed using AI where large volumes of public data can be readily processed to communicate shared narratives about shared values for future public works such as the rebuild of Christchurch.

year: 2024

title: Investigation into the effects of flow distribution on the photovoltaic performance of a building integrated photovoltaic/thermal solar collector

authors: Ghani, Faisal Abid

subjects: photovoltaic

abstract: The conversion of solar energy into usable forms of energy such as electricity and heat is attractive given the abundance of solar energy and the numerous issues recently raised in the consumption of fossil fuels. Solar conversion technologies may generally be categorised as either photovoltaic or solar thermal types capable of converting incidental sunlight into electricity and heat respectively. The photovoltaic cell is able to transform incidental sunlight into electricity via the Becquerel effect, however, the single junction crystalline silicon solar cell, the predominant cell type in today’s photovoltaic market is only able to utilise a small portion (less than 20%) of incidental sunlight for this purpose. A majority of the remaining portion is absorbed much like a traditional solar thermal collector and sunk as heat by the cell, elevating its operating temperature. Given the negative effect of temperature on photovoltaic cell operation, where a linearly proportional drop in conversion efficiency with elevated temperature can be expected, photovoltaic conversion can be reduced significantly particularly in areas of high irradiance and ambient temperatures. Based on the intrinsic absorption characteristics of the photovoltaic cell, a third type of solar panel referred to as the hybrid photovoltaic thermal collector (PVT) collector has been developed where fluid channels running along the underside of the photovoltaic panel transfer heat away from the cells to minimise this detrimental effect. Furthermore, heat captured from the cells may then be used for space heating or domestic hot water improving the overall collector efficiency.
In this study a unique building integrated PVT (BIPVT) collector is investigated consisting of an aluminium extrusion with structural ribs, fluid channels, and solar conversion materials. In order to evaluate this design, a mathematical model of the collector was developed in order to determine both thermal and electrical yield of the proposed design. The thermal analyses of the building integrated PVT collector in previous studies have generally adopted the approach applied to traditional solar thermal collectors where the distribution of coolant fluid flowing through the piping array is assumed uniform. For a conventional solar thermal collector this simplification may be reasonable under certain circumstances, however, given the temperature sensitivity of photovoltaic cells and their electrical connection scheme, this assumption may lead to significant modelling error. In order to further investigate this issue, a mathematical model has been developed to determine the photovoltaic yield of a BIPVT collector operating under non-homogeneous operating temperature as a result of flow maldistribution. The model is composed of three steps individually addressing the issues of 1) fluid flow, 2) heat transfer, and 3) the photovoltaic output of a BIPVT array. Fluid analysis was conducted using the finite element method in order to obtain the individual fluid channel flow rates. Using these values, a heat transfer analysis was then conducted for each module forming the BIPVT array to calculate the photovoltaic operating temperature for the constituent cells forming the array. During this step the finite difference method was utilised to approximate the fin efficiency of the building integrated collector, taking into account its irregular geometry. Finally the photovoltaic yield was calculated using a numerical approach which considered the individual operating temperature of the PV cells. During this step a new method was identified to determine the values of series and shunt resistances and also the diode constant required for the modelling of photovoltaic devices based on the multi-dimensional Newton-Raphson method and current-voltage equations expressed using the Lambert W-function. Experimentation was carried out to validate the new modelling methods.
These models were combined to quantify the detrimental impact of flow mal-distribution on photovoltaic yield for a number of scenarios. In the case where flow uniformity was poorest, only a 2% improvement in photovoltaic yield was obtained in comparison to a traditional photovoltaic panel operating under the same environmental conditions. For the case where flow uniformity was optimal however, photovoltaic output was improved by almost 10%.
This work has shown that the effects of poor flow distribution has the potential to have a substantial negative impact on the photovoltaic output of a building integrated solar collector especially given the variability in its physical geometry. The appropriate design of this technology should therefore consider the effects of this phenomenon. The methodology presented in this study can be used to approximate PV output for a BIPVT array with different array geometries and operating characteristics. Furthermore, the method to calculate solar cell modelling parameters developed in this study is not only useful for the analysis of hybrid PVT systems, but for the general analysis of photovoltaic systems based on crystalline silicon solar cells.

text: Investigation into the effects of flow distribution on the photovoltaic performance of a building integrated photovoltaic/thermal solar collector The conversion of solar energy into usable forms of energy such as electricity and heat is attractive given the abundance of solar energy and the numerous issues recently raised in the consumption of fossil fuels. Solar conversion technologies may generally be categorised as either photovoltaic or solar thermal types capable of converting incidental sunlight into electricity and heat respectively. The photovoltaic cell is able to transform incidental sunlight into electricity via the Becquerel effect, however, the single junction crystalline silicon solar cell, the predominant cell type in today’s photovoltaic market is only able to utilise a small portion (less than 20%) of incidental sunlight for this purpose. A majority of the remaining portion is absorbed much like a traditional solar thermal collector and sunk as heat by the cell, elevating its operating temperature. Given the negative effect of temperature on photovoltaic cell operation, where a linearly proportional drop in conversion efficiency with elevated temperature can be expected, photovoltaic conversion can be reduced significantly particularly in areas of high irradiance and ambient temperatures. Based on the intrinsic absorption characteristics of the photovoltaic cell, a third type of solar panel referred to as the hybrid photovoltaic thermal collector (PVT) collector has been developed where fluid channels running along the underside of the photovoltaic panel transfer heat away from the cells to minimise this detrimental effect. Furthermore, heat captured from the cells may then be used for space heating or domestic hot water improving the overall collector efficiency.
In this study a unique building integrated PVT (BIPVT) collector is investigated consisting of an aluminium extrusion with structural ribs, fluid channels, and solar conversion materials. In order to evaluate this design, a mathematical model of the collector was developed in order to determine both thermal and electrical yield of the proposed design. The thermal analyses of the building integrated PVT collector in previous studies have generally adopted the approach applied to traditional solar thermal collectors where the distribution of coolant fluid flowing through the piping array is assumed uniform. For a conventional solar thermal collector this simplification may be reasonable under certain circumstances, however, given the temperature sensitivity of photovoltaic cells and their electrical connection scheme, this assumption may lead to significant modelling error. In order to further investigate this issue, a mathematical model has been developed to determine the photovoltaic yield of a BIPVT collector operating under non-homogeneous operating temperature as a result of flow maldistribution. The model is composed of three steps individually addressing the issues of 1) fluid flow, 2) heat transfer, and 3) the photovoltaic output of a BIPVT array. Fluid analysis was conducted using the finite element method in order to obtain the individual fluid channel flow rates. Using these values, a heat transfer analysis was then conducted for each module forming the BIPVT array to calculate the photovoltaic operating temperature for the constituent cells forming the array. During this step the finite difference method was utilised to approximate the fin efficiency of the building integrated collector, taking into account its irregular geometry. Finally the photovoltaic yield was calculated using a numerical approach which considered the individual operating temperature of the PV cells. During this step a new method was identified to determine the values of series and shunt resistances and also the diode constant required for the modelling of photovoltaic devices based on the multi-dimensional Newton-Raphson method and current-voltage equations expressed using the Lambert W-function. Experimentation was carried out to validate the new modelling methods.
These models were combined to quantify the detrimental impact of flow mal-distribution on photovoltaic yield for a number of scenarios. In the case where flow uniformity was poorest, only a 2% improvement in photovoltaic yield was obtained in comparison to a traditional photovoltaic panel operating under the same environmental conditions. For the case where flow uniformity was optimal however, photovoltaic output was improved by almost 10%.
This work has shown that the effects of poor flow distribution has the potential to have a substantial negative impact on the photovoltaic output of a building integrated solar collector especially given the variability in its physical geometry. The appropriate design of this technology should therefore consider the effects of this phenomenon. The methodology presented in this study can be used to approximate PV output for a BIPVT array with different array geometries and operating characteristics. Furthermore, the method to calculate solar cell modelling parameters developed in this study is not only useful for the analysis of hybrid PVT systems, but for the general analysis of photovoltaic systems based on crystalline silicon solar cells.

year: 2013

title: Culture, Courage and Change: The experiences of a Te Kotahitanga facilitation team

authors: Lamont, Robyn Elizabeth

subjects: culturally responsive pedagogy of relations

abstract: This thesis explores the experiences of the Te Kotahitanga facilitation team in one of the 12 Phase 3 Te Kotahitanga schools between 2003 and 2006. The collaborative story through which those experiences are shared includes the voices of the Lead facilitator, the two co-principals, and an RTLB/facilitator. This thesis begins by seeking to understand the historical impact of culturally located discourses of colonisation on the lives of the indigenous Māori people in New Zealand. From within a platform of Māori theorising it also considers Kaupapa Māori research methodologies and explores Māori people’s aspirations for self determination (tino rangatiratanga). It then considers the principles and practices of engaging as a bicultural partnership to improve educational outcomes for Māori students. Through a discussion of the facilitation team's experiences of learning about a culturally responsive pedagogy of relations through the development and support of culturally responsive contexts for learning, three important themes emerge: culture, courage and change. The impact of deficit theorising and pathologising practices on the culture of Maori students and their teachers is examined. The courage required of the Te Kotahitanga principals and facilitators to challenge and disrupt the assumptions that underpinned the historical status quo in this school and the importance of remaining steadfast in response to the dissonance and resistance that these change processes created is then discussed. Finally, this thesis highlights both the interdependent nature of the change required and the power of the collective in creating change; change within ourselves, within our classrooms and within our schools and communities for the benefit of Māori students, and of all students.

text: Culture, Courage and Change: The experiences of a Te Kotahitanga facilitation team This thesis explores the experiences of the Te Kotahitanga facilitation team in one of the 12 Phase 3 Te Kotahitanga schools between 2003 and 2006. The collaborative story through which those experiences are shared includes the voices of the Lead facilitator, the two co-principals, and an RTLB/facilitator. This thesis begins by seeking to understand the historical impact of culturally located discourses of colonisation on the lives of the indigenous Māori people in New Zealand. From within a platform of Māori theorising it also considers Kaupapa Māori research methodologies and explores Māori people’s aspirations for self determination (tino rangatiratanga). It then considers the principles and practices of engaging as a bicultural partnership to improve educational outcomes for Māori students. Through a discussion of the facilitation team's experiences of learning about a culturally responsive pedagogy of relations through the development and support of culturally responsive contexts for learning, three important themes emerge: culture, courage and change. The impact of deficit theorising and pathologising practices on the culture of Maori students and their teachers is examined. The courage required of the Te Kotahitanga principals and facilitators to challenge and disrupt the assumptions that underpinned the historical status quo in this school and the importance of remaining steadfast in response to the dissonance and resistance that these change processes created is then discussed. Finally, this thesis highlights both the interdependent nature of the change required and the power of the collective in creating change; change within ourselves, within our classrooms and within our schools and communities for the benefit of Māori students, and of all students.

year: 2011