Probabilistic performance assessment of complex energy process systems – The case of a self-sustained sanitation system

Athanasios Kolios,Ying Jiang,Tosin Somorin,Ayodeji Sowale,Aikaterini Anastasopoulou,Edward J Anthony,Beatriz Fidalgo,Alison Parker,Ewan Mcadam,Leon Williams,Matt Collins,Sean Tyrrel

doi:10.1016/j.enconman.2018.02.046

Athanasios Kolios, Ying Jiang + Show 10 more

Open Access

https://doi.org/10.1016/j.enconman.2018.02.046

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Journal: Energy Conversion	Publication Date: Feb 22, 2018
Citations: 14	License type: cc-by

Affiliation: Cranfield University

Abstract

A 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.

Highlights

In many developing countries, providing people with access to safe drinking water and hygienic sanitation facility is a key challenge to prevent the spread of infectious diseases
The results show that the main energy-intensive component of the Nano-membrane toilet (NMT) system is the dryer, which requires 41.2 W, i.e. ∼62% of the Stirling Engine (SE) power output
This study demonstrated the feasibility of a novel design of an NMT powered by energy produced from human faeces

Summary

Introduction

In many developing countries, providing people with access to safe drinking water and hygienic sanitation facility is a key challenge to prevent the spread of infectious diseases. Sustainable ‘offgrid’ decentralised sanitation technologies are widely promoted by many international initiatives [3], as they are more suitable for regions with poor infrastructure. Sanitation systems such as rainwater-flushedtoilets, waterless urinals and composting toilets have been suggested in various studies as potential solutions to reduce or eliminate the use of potable water and improve rural health conditions [3,4]. There are still strong technological and humanitarian incentives for the development of novel sanitation systems to improve the quality of life and disease control

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Results

Conclusion