Browsing by Author "Collins, Matt"
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Item Open Access Comparative evaluation of competing technologies through rapid prototyping(2018-07) Hart, Connor; Collins, Matt; Jarvis, PeterA major difficulty often experienced by multidisciplinary teams, particularly between scientific and design led approaches, is how to resolve the conflict which arises between competing ideas, in order to facilitate the most efficient path towards a successful technological innovation. This project has attempted to demonstrate the vital role which agile innovation, made possible only through rapid prototyping, can optimise two competing technologies in-order that they can be tested and evaluated across a spectrum of qualitative and quantitative parameters. The results of which can enable the wider project team to select the correct path forward. A systematic review of literature revealed that design literature in this space is limited, with few real-world case studies conducted in this area. This research provides a valuable practical case study which shows agile innovation in action and the critical role which rapid prototype plays in that process. A multi-category matrix was newly created, providing metrics for both qualitative and quantitative data, and which uses a colour-coded scoring system to give a detailed and overall rating for each technology. The findings were controversial, but unequivocal, and could have a major impact on the development of the wider project going forward.Item Open Access Faeces - Urine separation via settling and displacement: Prototype tests for a novel non-sewered sanitation system(Elsevier, 2020-08-23) Hennigs, Jan; Ravndal, Kristin T.; Parker, Alison; Collins, Matt; Jiang, Ying; Kolios, Athanasios J.; McAdam, Ewan; Williams, Leon; Tyrrel, Sean F.The development of novel, non-sewered sanitation systems like the Nano Membrane Toilet requires thorough investigation of processes that may seem well-understood. For example, unlike the settling of primary sludge, the separation of solids from liquids in a small-volume container at the scale of a household toilet has not been studied before. In two sets of experiments, the settling of real faeces and toilet paper in settling columns and the settling of synthetic faeces in a conical tank are investigated to understand the factors affecting the liquid quality for downstream treatment processes. Toilet paper is found to be a major inhibitor to settling of solids. While a lower overflow point results in better phase separation through displacement of liquid, a higher overflow point and frequent removal of solids may be more advantageous for the liquid qualityItem Open Access Field testing of a prototype mechanical dry toilet flush(Elsevier, 2019-02-17) Hennigs, Jan; Ravndal, Kristin T.; Blose, Thubelihle; Toolaram, Anju; Sindall, Rebecca C.; Barrington, Dani J.; Collins, Matt; Engineer, Bhavin; Kolios, Athanasios J.; McAdam, Ewan; Parker, Alison; Williams, Leon; Tyrrel, SeanA prototype of a non-fluid based mechanical toilet flush was tested in a semi-public, institutional setting and in selected peri-urban households in eThekwini municipality, Republic of South Africa. The mechanism's functionality and users' perception of the flush were assessed. User perception varied depending on background: Users accustomed to porcelain water flush toilets were open to, yet reserved about the idea of using a waterless flush in their homes. Those who commonly use Urine Diversion Dehydration Toilets were far more receptive. The user-centred field trials were complemented by a controlled laboratory experiment, using synthetic urine, -faeces, and -menstrual blood, to systematically assess the efficiency of three swipe materials to clean the rotating bowl of the flush. A silicone rubber with oil-bleed-effect was found to be the best performing material for the swipe. Lubrication of the bowl prior to use further reduced fouling. A mechanical waterless flush that does not require consumables, like plastic wrappers, is a novelty and could – implemented in existing dry toilet systems – improve acceptance and thus the success of waterless sanitation.Item Open Access Impact of fouling, cleaning and faecal contamination on the separation of water from urine using thermally driven membrane separation(Taylor & Francis, 2018-02-12) Kamranvand, Farhad; Davey, Christopher; Sakah, H.; Autin, Olivier; Mercer, E.; Collins, Matt; Williams, Leon; Kolios, Athanasios; Parker, Alison; Tyrrel, Sean; Cartmell, Elise; McAdam, EwanIn this study, membrane distillation is evaluated as a technology for non-sewered sanitation, using waste heat to enable separation of clean water from urine. Whilst membrane fouling was observed for urine, wetting was not evident and product water quality met the proposed discharge standard, despite concentration of the feed. Fouling was reversible using physical cleaning, which is similar to previous membrane studies operating without pressure as the driving force. High chemical oxygen demand reduction was achieved following faecal contamination, but mass transfer was impeded and wetting occurred which compromised permeate quality, suggesting upstream intervention is demanded to limit the extent of faecal contamination.Item Open Access Non-isothermal thermogravimetric kinetic analysis of the thermochemical conversion of human faeces(Elsevier, 2018-08-29) Fidalgo, Beatriz; Chilmeran, M.; Somorin, Tosin Onabanjo; Sowale, Ayodeji; Kolios, Athanasios; Parker, Alison; Williams, Leon; Collins, Matt; McAdam, Ewan J.; Tyrrel, Sean F.The “Reinvent the Toilet Challenge” set by the Bill & Melinda Gates Foundation aims to bring access to adequate sanitary systems to billions of people. In response to this challenge, on-site sanitation systems are proposed and being developed globally. These systems require in-situ thermal treatment, processes that are not well understood for human faeces (HF). Thermogravimetric analysis has been used to investigate the pyrolysis, gasification and combustion of HF. The results are compared to the thermal behaviour of simulant faeces (SF) and woody biomass (WB), along with the blends of HF and WB. Kinetic analysis was conducted using non-isothermal kinetics model-free methods, and the thermogravimetric data obtained for the combustion of HF, SS and WB. The results show that the devolatilisation of HF requires higher temperatures and rates are slower those of WB. Minimum temperatures of 475 K are required for fuel ignition. HF and SF showed similar thermal behaviour under pyrolysis, but not under combustion conditions. The activation energy for HF is 157.4 kJ/mol, relatively higher than SS and WB. Reaction order for HF is lower (n = 0.4) to WB (n = 0.6). In-situ treatment of HF in on-site sanitary systems can be designed for slow progressive burn.Item Open Access Planning and communicating prototype tests for the Nano Membrane Toilet: A critical review and proposed strategy(Gates Open Research, 2019-08-30) Hennigs, Jan; Parker, Alison; Collins, Matt; Jiang, Ying; Kolios, Athanasios; McAdam, Ewan J.; Williams, LeonUrban sanitation in growing cities of the Global South presents particular challenges. This led to the Bill & Melinda Gates Foundation’s Reinvent The Toilet Challenge, which sparked the development of various non-sewered sanitation technologies like the Nano Membrane Toilet. Complex disruptive technologies like this entail an extensive product development process, including various types of prototype tests. While there is an abundance of literature discussing how to build prototypes, and the optimal number of tests, there has been little focus on how to plan and conduct tests, especially in a development endeavour of this complexity. Four approaches to testing are reviewed, and their strengths and weaknesses compared. A visualised testing strategy is proposed that encompasses the entire product development process and can be used to plan and communicate prototype tests for the Nano Membrane Toilet to ultimately achieve compliance with international standards.Item Open Access Probabilistic performance assessment of complex energy process systems - The case of a self-sustained sanitation system(Elsevier, 2018-02-22) Kolios, Athanasios; Jiang, Ying; Somorin, Tosin; Sowale, Ayodeji; Anastasopoulou, Aikaterini; Anthony, Edward J.; Fidalgo, Beatriz; Parker, Alison; McAdam, Ewan; Williams, Leon; Collins, Matt; Tyrrel, SeanA probabilistic modelling approach was developed and applied to investigate the energy and environmental performance of an innovative sanitation system, the “Nano-membrane Toilet” (NMT). The system treats human excreta via an advanced energy and water recovery island with the aim of addressing current and future sanitation demands. Due to the complex design and inherent characteristics of the system’s input material, there are a number of stochastic variables which may significantly affect the system’s performance. The non-intrusive probabilistic approach adopted in this study combines a finite number of deterministic thermodynamic process simulations with an artificial neural network (ANN) approximation model and Monte Carlo simulations (MCS) to assess the effect of system uncertainties on the predicted performance of the NMT system. The joint probability distributions of the process performance indicators suggest a Stirling Engine (SE) power output in the range of 61.5–73 W with a high confidence interval (CI) of 95%. In addition, there is high probability (with 95% CI) that the NMT system can achieve positive net power output between 15.8 and 35 W. A sensitivity study reveals the system power performance is mostly affected by SE heater temperature. Investigation into the environmental performance of the NMT design, including water recovery and CO2/NOx emissions, suggests significant environmental benefits compared to conventional systems. Results of the probabilistic analysis can better inform future improvements on the system design and operational strategy and this probabilistic assessment framework can also be applied to similar complex engineering systems.Item Open Access Thermodynamic analysis of a gamma type Stirling engine in an energy recovery system(Elsevier, 2018-04-01) Sowale, Ayodeji; Kolios, Athanasios J.; Fidalgo, Beatriz; Somorin, Tosin; Parker, Alison; Williams, Leon; Collins, Matt; McAdam, Ewan; Tyrrel, SeanThe demand for better hygiene has increased the need for developing more effective sanitation systems and facilities for the safe disposal of human urine and faeces. Non-Sewered Sanitary systems are considered to be one of the promising alternative solutions to the existing flush toilet system. An example of these systems is the Nano Membrane Toilet (NMT) system being developed at Cranfield University, which targets the safe disposal of human waste while generating power and recovering water. The NMT will generate energy from the conversion of human waste with the use of a micro-combustor; the heat produced will power a Stirling engine connected to a linear alternator to generate electricity. This study presents a numerical investigation of the thermodynamic analysis and operational characteristics of a quasi steady state model of the gamma type Stirling engine integrated into a combustor in the back end of the NMT system. The effects of the working gas, at different temperatures, on the Stirling engine performance are also presented. The results show that with the heater temperature of 390 °C from the heat supply via conduction at 820 W from the flue gas, the Stirling engine generates a daily power output of 27 Wh/h at a frequency of 23.85 Hz.