title: Unified Total Site Heat Integration: Targeting, Optimisation and Network Design

authors: Tarighaleslami, Amir Hossein

subjects: Total Site Heat Integration

abstract: Process industries in New Zealand use 214.3 PJ of process heat, of which approximately 65 % is fossil fuels. Despite increasing energy demands, depleting fossil fuel resources, and pressure to reduce Greenhouse Gas emissions, low grade heat in large-scale processing sites is still not fully utilised. This thesis presents methods to target, optimise and design more practical heat recovery systems for large industrial sites, i.e. Total Sites, and overcome technical limitations of current methods. Original contributions of this thesis to literature include novel developments and applications in six areas: i) a new Total Site Heat Integration (TSHI) targeting method – Unified Total Site Targeting (UTST) –  which sets realistic targets for isothermal and non-isothermal utilities and heat recovery via the utility system; ii) a new TSHI optimisation and utility temperature selection method to optimise Total Cost of the utility system; iii) a new Utility Exchanger Network synthesis and design method based on the targets achieved by the UTST method and optimal temperatures from optimisation method; iv) a new method for calculating assisted heat transfer and shaft work to further improve TSHI cogeneration and performance; v) examination of heat transfer enhancement techniques in TSHI to achieve higher heat recovery and lower required area by substituting conventional utility mediums by nanofluids in the utility system; and vi) a spreadsheet software tool called Unified Total Site Integration to apply the developed methods to real industrial cases. 
The developed methods have been applied to three large industrial case studies. Results confirm that heat recovery and utility targets obtained from the UTST method were lower but more realistic to achieve in practice when compared to conventional TSHI methods. The three industrial case studies represent a wide variety of processing industries. In summary, the over-estimation of TSHI targets for the three case studies from using the conventional method compared to the new method are 0.2 % for the Södra Cell Värö Kraft Pulp Mill, 22 % for a New Zealand Dairy Factory, and 0.1 % for Petrochemical Complex. The Total Annualised Costs (TAC) for the three case studies are minimised using a new derivative based approach. Results show TAC reductions 4.6 % for Kraft Pulp Mill, 0.6 % for Dairy Factory, and 3.4 % for Petrochemical Complex case studies. In addition, sensitivity analysis for the optimisation is undertaken. The UTST method with its modified targeting procedure is demonstrated to generate simpler Utility Exchanger Network designs compared to conventional methods, which confirm the original targets are realistic and achievable. A new method for calculating assisted heat integration targets applied to an example Total Site problem increased heat recovery by 1,737 kW, which is a 21% increase in Total Site heat recovery, and increased shaft work by 80 kW. Lastly, the addition of nanoparticles to create a closed nanofluid heat recovery systems shows heat recovery from liquid-liquid heat exchangers increases of 5 % to 9 % using an intermediate fluid with 1.5 vol. % CuO/water.

text: Unified Total Site Heat Integration: Targeting, Optimisation and Network Design Process industries in New Zealand use 214.3 PJ of process heat, of which approximately 65 % is fossil fuels. Despite increasing energy demands, depleting fossil fuel resources, and pressure to reduce Greenhouse Gas emissions, low grade heat in large-scale processing sites is still not fully utilised. This thesis presents methods to target, optimise and design more practical heat recovery systems for large industrial sites, i.e. Total Sites, and overcome technical limitations of current methods. Original contributions of this thesis to literature include novel developments and applications in six areas: i) a new Total Site Heat Integration (TSHI) targeting method – Unified Total Site Targeting (UTST) –  which sets realistic targets for isothermal and non-isothermal utilities and heat recovery via the utility system; ii) a new TSHI optimisation and utility temperature selection method to optimise Total Cost of the utility system; iii) a new Utility Exchanger Network synthesis and design method based on the targets achieved by the UTST method and optimal temperatures from optimisation method; iv) a new method for calculating assisted heat transfer and shaft work to further improve TSHI cogeneration and performance; v) examination of heat transfer enhancement techniques in TSHI to achieve higher heat recovery and lower required area by substituting conventional utility mediums by nanofluids in the utility system; and vi) a spreadsheet software tool called Unified Total Site Integration to apply the developed methods to real industrial cases. 
The developed methods have been applied to three large industrial case studies. Results confirm that heat recovery and utility targets obtained from the UTST method were lower but more realistic to achieve in practice when compared to conventional TSHI methods. The three industrial case studies represent a wide variety of processing industries. In summary, the over-estimation of TSHI targets for the three case studies from using the conventional method compared to the new method are 0.2 % for the Södra Cell Värö Kraft Pulp Mill, 22 % for a New Zealand Dairy Factory, and 0.1 % for Petrochemical Complex. The Total Annualised Costs (TAC) for the three case studies are minimised using a new derivative based approach. Results show TAC reductions 4.6 % for Kraft Pulp Mill, 0.6 % for Dairy Factory, and 3.4 % for Petrochemical Complex case studies. In addition, sensitivity analysis for the optimisation is undertaken. The UTST method with its modified targeting procedure is demonstrated to generate simpler Utility Exchanger Network designs compared to conventional methods, which confirm the original targets are realistic and achievable. A new method for calculating assisted heat integration targets applied to an example Total Site problem increased heat recovery by 1,737 kW, which is a 21% increase in Total Site heat recovery, and increased shaft work by 80 kW. Lastly, the addition of nanoparticles to create a closed nanofluid heat recovery systems shows heat recovery from liquid-liquid heat exchangers increases of 5 % to 9 % using an intermediate fluid with 1.5 vol. % CuO/water.

year: 2018

title: Evaluation of agri-environmental policies for reducing nitrate pollution from New Zealand dairy farms accounting for firm heterogeneity

authors: Doole, Graeme J.

subjects: diffuse pollution

abstract: Policy makers worldwide are interested in the identification of cost-effective policy instruments to reduce diffuse pollution. A large economic model representing heterogeneous farms is used to evaluate a broad set of policies for reducing nitrate regulation within a large catchment dominated by dairy production. A policy instrument that allows the level of abatement to vary among producers according to differences in abatement cost is most cost-effective. The primary goal of 26 kg N ha(-1) can be achieved at a cost of $15 ha(-1) under this cap and trade policy, while a uniform cap on emissions for all farmers would be more than three times as expensive ($49 ha(-1)). In contrast, requiring uniform reductions in stocking rate, banning the application of nitrogen fertiliser, and land retirement perform poorly. These instruments are at least three times more costly than a cap and trade policy over all simulated reductions. Moreover, the differentiated policy does not greatly alter the distribution of farm profit, relative to what exists without regulation. The use of a large, complex economic model incorporating disaggregated farms provides unique insight into the economic benefits accruing to a differentiated policy.

text: Evaluation of agri-environmental policies for reducing nitrate pollution from New Zealand dairy farms accounting for firm heterogeneity Policy makers worldwide are interested in the identification of cost-effective policy instruments to reduce diffuse pollution. A large economic model representing heterogeneous farms is used to evaluate a broad set of policies for reducing nitrate regulation within a large catchment dominated by dairy production. A policy instrument that allows the level of abatement to vary among producers according to differences in abatement cost is most cost-effective. The primary goal of 26 kg N ha(-1) can be achieved at a cost of $15 ha(-1) under this cap and trade policy, while a uniform cap on emissions for all farmers would be more than three times as expensive ($49 ha(-1)). In contrast, requiring uniform reductions in stocking rate, banning the application of nitrogen fertiliser, and land retirement perform poorly. These instruments are at least three times more costly than a cap and trade policy over all simulated reductions. Moreover, the differentiated policy does not greatly alter the distribution of farm profit, relative to what exists without regulation. The use of a large, complex economic model incorporating disaggregated farms provides unique insight into the economic benefits accruing to a differentiated policy.

year: 2013

title: Kimihia, rangahaua ngā tikanga heke iho. He taonga huahua e riro mai: Exploring whakapapa as a tool towards a kaupapa Māori assessment framework in early childhood education

authors: Paki, Vanessa Anne

subjects: kaupapa Maori assessment

abstract: This study explores whakapapa as a tool, which can be used as a kaupapa Māori assessment framework in early childhood education, positioning kaupapa Māori theory as a paradigm base underpinning a philosophical and theoretical discourse towards assessment for children's learning. This thesis represents the culmination of a personal and professional journey, derived from the writer's longstanding interest in and commitment to kaupapa Māori early childhood education, and more specifically, philosophies and practices for assessment in this context. The study has canvassed a vast terrain of kaupapa Māori philosophy in its search for a theoretical grounding for a kaupapa Māori assessment framework for early childhood education.
Foundation to the study has been the premise that the notion of whakapapa serves as an overarching philosophical matrix, encompassing the interconnected realms of genealogy, spirituality, and knowledge that precede, surround, and embrace the Māori child. Throughout the thesis, diagrams are employed to demonstrate and model the whakapapa underpinning the conceptualisations being explored. After contextualising the study within a historical overview of the impact of colonisation of kaupapa Māori education and research, it is suggested that a re-examination of key concepts from tikanga Māori will illuminate transformative possibilities applicable to the study's focus on the development of a theoretical base for an assessment tool within kaupapa Māori early childhood settings. Drawing from the literature, the thesis re-positions the view of the Māori child to one of being nurtured within a philosophical construct underpinned and immersed in tikanga such as whakapapa, ira tangata, whanaungatanga, mana and tapu, and ako, providing a strongly Māori theoretical base for the envisioning of the assessment process. The outcome of this study is to propose an assessment framework, which embodies and reflects these core kaupapa Māori philosophies as praxis.

text: Kimihia, rangahaua ngā tikanga heke iho. He taonga huahua e riro mai: Exploring whakapapa as a tool towards a kaupapa Māori assessment framework in early childhood education This study explores whakapapa as a tool, which can be used as a kaupapa Māori assessment framework in early childhood education, positioning kaupapa Māori theory as a paradigm base underpinning a philosophical and theoretical discourse towards assessment for children's learning. This thesis represents the culmination of a personal and professional journey, derived from the writer's longstanding interest in and commitment to kaupapa Māori early childhood education, and more specifically, philosophies and practices for assessment in this context. The study has canvassed a vast terrain of kaupapa Māori philosophy in its search for a theoretical grounding for a kaupapa Māori assessment framework for early childhood education.
Foundation to the study has been the premise that the notion of whakapapa serves as an overarching philosophical matrix, encompassing the interconnected realms of genealogy, spirituality, and knowledge that precede, surround, and embrace the Māori child. Throughout the thesis, diagrams are employed to demonstrate and model the whakapapa underpinning the conceptualisations being explored. After contextualising the study within a historical overview of the impact of colonisation of kaupapa Māori education and research, it is suggested that a re-examination of key concepts from tikanga Māori will illuminate transformative possibilities applicable to the study's focus on the development of a theoretical base for an assessment tool within kaupapa Māori early childhood settings. Drawing from the literature, the thesis re-positions the view of the Māori child to one of being nurtured within a philosophical construct underpinned and immersed in tikanga such as whakapapa, ira tangata, whanaungatanga, mana and tapu, and ako, providing a strongly Māori theoretical base for the envisioning of the assessment process. The outcome of this study is to propose an assessment framework, which embodies and reflects these core kaupapa Māori philosophies as praxis.

year: 2007