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Optimization modeling is popular for evaluating the design of energy systems in a given urban area. This is largely because the design of urban energy systems requires to make complex decisions about the choice of technologies, their location, and the fuels they use. This study presents an approach for modeling and optimizing decisions for retrofitting urban energy systems, with a focus on the optimal...
A cooling water system requires a large amount of power to send water to coolers installed at high platform. In spite of pressure drop, most power is not consumed, but turns to potential energy. The potential energy will turn back to pressure once cooling water goes down from high, but the pressure is wasted in current cooling water system. In this work, hydro turbines are used to recover surplus...
The current study presents an experimental analysis for integrating a phase change material (PCM) in a typical direct flow evacuated tube solar water heater with a U-tube heat exchanger (HX). Each evacuated tube is filled with 0.8 kg of paraffin wax to store the absorbed incident solar energy. As water flows through the U-shape copper tube inside the PCM, the stored energy is transferred to the water...
In recent years, wind power has played a significant role in energy generation of micro-grids (MGs). However, randomness nature of wind speed leading to uncertainty in wind power forecast, imposes some problems such as overestimating wind power on optimized scheduling of MG. In this paper, we propose an adaptive probabilistic concept of confidence interval (APCCI) to address these problems. The main...
The work focuses on the experimental study of the heat diode mechanism in an Integrated Collector Storage Solar Water Heater (ICSSWH) for domestic applications. The solar device combines a horizontal cylindrical vessel with an asymmetric reflector trough (Compound Parabolic Concentrator – CPC). The cylindrical storage tank comprises two concentric cylindrical vessels: the outer absorbing vessel and...
This paper considers cost allocation in networks where agents are characterized by stochastic demand and supply of a non-storable good, e.g. green energy. The grid itself creates possibilities of exchanging energy between agents and we propose to allocate common costs in proportion to the economic gain of being part of the grid. Our model includes a set of fundamental requirements for the associated...
A considerable amount of energy consumed by machine tools is attributable to non-cutting operations, including tool path, tool change, and change of spindle rotation speed. The non-cutting energy consumption of the machine tool (NCE) is affected by the processing sequence of the features of a specific part (PFS) because the plans of non-cutting operations will vary based on the different PFS. This...
Electricity storage (ES) has the potential of offering several energy system benefits but different technologies also offer different services which can be traded on different markets. In this study, a combined assessment methodology is proposed, enabling a benchmark comparison of stationary electricity storage technologies for different time and system scales, considering their technical, economic...
This paper presents the analysis of the impact of dispersed source production on the electric distribution network. The focus is on the production of electric energy by photovoltaic systems in public distribution networks. Photovoltaic systems may in certain cases influence voltage quality in public distribution networks, which is determined by the EN 50160 standard. Photovoltaic systems affect the...
A heat pipe based pyrolysis chamber has been developed and tested as an efficient, cost effective and space saving municipal waste treatment unit. The performance of the chamber was evaluated based on the temperature distributions inside the chamber, its electricity consumption and the chemical characteristics of the final pyrolysis products (bio-chars and pyro-oils) obtained from the process and...
This paper compares the electricity, heating, and cooling sectors at national level for various European countries. Annual energy demands are compared for all 28 EU countries, while peak hourly demands are compared for four countries that vary significantly. The results indicate that the heat demand is currently the largest of the three demand types considered in terms of both annual and peak demands:...
Pinus Patula is widely distributed in Colombia and has become a useful timber specie for reforestation programs. Forest biomass can be used to produce directly hydrogen through thermochemical technologies (e.g. gasification). The aim of this work is to assess the environmental impact of hydrogen production via gasification using P. patula as raw material. The life cycle assessment was carried out...
Chemical heat pump are promising alternatives in waste heat recovery applications. The present paper focuses on the technical and economic feasibility analysis of the Isopropanol-Acetone-Hydrogen Chemical Heat Pump (IAH-CHP) system. A small scale prototype of the IAH-CHP was established. Coefficient of performance (COP), exergy efficiency and entransy efficiency analysis were adopted to evaluate the...
Particle suspensions can be used in Solar Power Towers to capture the solar heat at a high temperature, and convey it to the storage and the subsequent use in the power block. Thermal Energy Storage (TES) needs to be integrated. Temperatures of 600–900 °C foster the use of high-efficiency power generation cycles. Appropriate Phase Change Materials (PCMs) in that temperature range were examined, i...
The organic Rankine cycle (ORC) is a promising method of generating power that utilizes low-enthalpy renewable energy and industrial waste heat. Given that the exergy loss and capital investment cost of heat exchangers account for a large proportion of the components in the ORC, research on the development of novel heat exchangers and configuration optimization coupling with other components and cycle...
This work aims at proposing a sliding mode observer (SMO) based nonlinear multivariable sliding mode controller (SMC) and globally linearizing controller (GLC) for a proton exchange membrane fuel cell (PEMFC). First, a nonlinear dynamic model of a methanol reformer is developed to produce hydrogen for the PEMFC. The reformer model has been verified and then its parameter values are modified to scale-up...
Acetone–Butanol–Ethanol (ABE), the intermediate product to produce bio-butanol is used as an alternative fuel directly to eliminate needless production costs. In this study, the droplet burning characteristics of neat ABE, diesel and ABE-diesel blends (10%, 20%, 30%, 50% of ABE (vol%)) fuels are investigated by the droplet free falling technique under atmospheric pressure. The initial droplet temperature...
The modelling of whole urban districts requires an automated process to parameterize simulation tools. This paper presents a validated methodology for fully automated building modelling within urban districts based on publicly available data. Dynamic building models with detailed heating systems are created in the simulation environment IDA ICE. The method of data collecting and processing and result...
The membrane electrode assembly plays an important role in determining performance of a PEM fuel cell but the mass transport and electrochemical reactions inside are extremely complex. Recently more research efforts are made on modeling cathode catalyst layer to explain phenomena related to water content. In this paper, a pseudo two-dimensional model of cathode catalyst layer together with a one-dimensional...
Using high-throughput sequencing technology based on 16S rRNA genes and the determination of abiotic factors, the metabolic pathways and microbial community dynamics were analyzed in a batch biogas fermentation process with pig manure as the feedstock at 15 °C. The results showed the followings. 1) The decomposition rate of cellulose and semi-cellulose were close to maximal level at day 40.2) At the...
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