title: Investigation of thermal aspects of building integrated photovoltaic/thermal solar collectors

authors: Anderson, Timothy Nicholas

subjects: photovoltaic thermal

abstract: In this study a novel building integrated photovoltaic/thermal (BIPVT) solar collector was developed, tested, modelled and optimised both experimentally and theoretically. Experimental testing found that glazing the prototype collector improved the maximum thermal efficiency by approximately 25% and decreased heat loss, by a factor of two, relative to an unglazed collector. Additionally, the spectral absorptance of a photovoltaic (PV) cell and several coloured absorber samples were characterised.

The experimental data was subsequently used in the development and validation of an optimisation model for BIPVT style collectors. Numerical optimisation showed that the collector thermal efficiency could be improved by maximising the geometric fin efficiency, reducing the thermal resistance between the PV cells and the absorber, and by increasing the transmittance-absorptance product of the PV cells and/or the absorber. The results showed that low cost materials, such as mild steel, could be used without significantly affecting the BIPVTs thermal efficiency. It was also shown that there was potential to develop coloured BIPVT collectors with acceptable thermal efficiencies. Finally, the model showed that potentially the air space in an attic could be used rather than  traditional  insulating materials.

Subsequent computational and experimental fluid dynamics studies found that the heat transfer coefficients in a scale-model attic would result in R-values similar to mineral wool type insulation and therefore may provide sufficient insulation of a BIPVT in a cold roof building. In these studies the validity of an existing correlation for natural convection in an attic-shaped enclosure was extended to Grashof numbers in the range 10^7 to 10^9 from its previous range, 2.9 x 10^6 to 9 x 10^6. 

The use of a single vertically mounted baffle was also found to reduce the natural convection heat transfer coefficients in attic-shaped enclosures. This led to the development of a new generalised correlation that can be used to determine the Nusselt number in an attic-shaped enclosure with regard to the proportions of the baffle.

This work has shown that it is possible to achieve satisfactory thermal performance from BIPVT style collectors fabricated from low cost materials such as colour coated mild steel. Further it has demonstrated that there is potential to reduce the cost of such systems by integrating them into a building rather than onto a building.

text: Investigation of thermal aspects of building integrated photovoltaic/thermal solar collectors In this study a novel building integrated photovoltaic/thermal (BIPVT) solar collector was developed, tested, modelled and optimised both experimentally and theoretically. Experimental testing found that glazing the prototype collector improved the maximum thermal efficiency by approximately 25% and decreased heat loss, by a factor of two, relative to an unglazed collector. Additionally, the spectral absorptance of a photovoltaic (PV) cell and several coloured absorber samples were characterised.

The experimental data was subsequently used in the development and validation of an optimisation model for BIPVT style collectors. Numerical optimisation showed that the collector thermal efficiency could be improved by maximising the geometric fin efficiency, reducing the thermal resistance between the PV cells and the absorber, and by increasing the transmittance-absorptance product of the PV cells and/or the absorber. The results showed that low cost materials, such as mild steel, could be used without significantly affecting the BIPVTs thermal efficiency. It was also shown that there was potential to develop coloured BIPVT collectors with acceptable thermal efficiencies. Finally, the model showed that potentially the air space in an attic could be used rather than  traditional  insulating materials.

Subsequent computational and experimental fluid dynamics studies found that the heat transfer coefficients in a scale-model attic would result in R-values similar to mineral wool type insulation and therefore may provide sufficient insulation of a BIPVT in a cold roof building. In these studies the validity of an existing correlation for natural convection in an attic-shaped enclosure was extended to Grashof numbers in the range 10^7 to 10^9 from its previous range, 2.9 x 10^6 to 9 x 10^6. 

The use of a single vertically mounted baffle was also found to reduce the natural convection heat transfer coefficients in attic-shaped enclosures. This led to the development of a new generalised correlation that can be used to determine the Nusselt number in an attic-shaped enclosure with regard to the proportions of the baffle.

This work has shown that it is possible to achieve satisfactory thermal performance from BIPVT style collectors fabricated from low cost materials such as colour coated mild steel. Further it has demonstrated that there is potential to reduce the cost of such systems by integrating them into a building rather than onto a building.

year: 2009

title: Ethnic and religious discrimination? A multicultural analysis of muslim minorities in the west

authors: Foroutan, Yaghoob

abstract: Using a discrimination approach, this paper analyzes the consequence of religious affiliation on the status of female migrants in the labor market. Available literature emphasizes the fact that the combination of a set of major sources of discrimination such as gender, migration, ethnicity, and religion makes more severe the existing discrimination. In order to examine this relationship, the paper utilizes the statistical method of logistic regression to determine the effect of religion while other competing determinants such as ethnic and migration characteristics as well as human capital and family characteristics are held constant in the analysis. Accordingly, it is proposed that the analysis undertaken in this paper has a good potential to advance the existing knowledge on the role of religion and ethnicity from a discrimination perspective. Key findings of this empirical investigation suggest that employment differentials tend to be mainly the consequence of achieved characteristics such as human capital and length of residence in the country of destination rather than the act of discrimination in the labor market per se, arising from characteristics such as migration status, religion, and ethnicity. However, further collaborations especially qualitative studies are required to shed further light on the complicated issue of ethnic and religious discrimination.

text: Ethnic and religious discrimination? A multicultural analysis of muslim minorities in the west Using a discrimination approach, this paper analyzes the consequence of religious affiliation on the status of female migrants in the labor market. Available literature emphasizes the fact that the combination of a set of major sources of discrimination such as gender, migration, ethnicity, and religion makes more severe the existing discrimination. In order to examine this relationship, the paper utilizes the statistical method of logistic regression to determine the effect of religion while other competing determinants such as ethnic and migration characteristics as well as human capital and family characteristics are held constant in the analysis. Accordingly, it is proposed that the analysis undertaken in this paper has a good potential to advance the existing knowledge on the role of religion and ethnicity from a discrimination perspective. Key findings of this empirical investigation suggest that employment differentials tend to be mainly the consequence of achieved characteristics such as human capital and length of residence in the country of destination rather than the act of discrimination in the labor market per se, arising from characteristics such as migration status, religion, and ethnicity. However, further collaborations especially qualitative studies are required to shed further light on the complicated issue of ethnic and religious discrimination.

year: 2011

title: The display and conservation of taonga Māori - establishing culturally appropriate dislay and conversation facilities: Mahi Māreikura - a work in progress

authors: Whaanga, Hēmi

subjects: Māori art objects

abstract: This paper examines issues relating to the appropriate display and conservation of taonga Māori in the context of a discussion of the establishment of Mahi Māreikura, a room in the University of Waikato library that is dedicated primarily to the display and conservation of the collected taonga and works of the late Dr. Pei te Hurinui Jones and a collection of the work of his colleague and close relative, Professor Bruce Biggs.

text: The display and conservation of taonga Māori - establishing culturally appropriate dislay and conversation facilities: Mahi Māreikura - a work in progress This paper examines issues relating to the appropriate display and conservation of taonga Māori in the context of a discussion of the establishment of Mahi Māreikura, a room in the University of Waikato library that is dedicated primarily to the display and conservation of the collected taonga and works of the late Dr. Pei te Hurinui Jones and a collection of the work of his colleague and close relative, Professor Bruce Biggs.

year: 2006