The environmental impact of the energy sector and the security and economics of energy supply and utilization have been raising increasing concerns, stimulating the search for innovative solutions for a sustainable use of resources. This article provides an overview of published research in this area, with a focus on papers contributed in special issues of leading journals dedicated to the series of Conferences on Sustainable Development of Energy, Water and Environment Systems (SDEWES), including the articles in the current special issue. Based on this review, research trends are identified and achievements supporting the energy transition are highlighted. The studies that focused on regional or urban energy planning have aimed at (a) increasing penetration of renewable energy sources, (b) optimizing the mix of centralized and distributed technologies (c) introducing additional flexibility in the power sector and d) identifying solutions for sustainable heating. Conversely, researches focused on individual plants or users have targeted the development of technologies for efficient energy use in industry and buildings, with emphasis on multigeneration and waste heat utilisation. The analysis highlights that future scenarios based on sustainable energy systems are viable, although their implementation will require further efforts by researchers and investors and active involvement of consumers.
District heating systems already play an important role in increasing the
sustainability of the heating sector and decreasing its environmental
impact. However, a high share of these systems is old and inefficient and
therefore needs to change towards the 4th generation district heating, which
will incorporate various energy sources, including renewables and excess
heat of different origins. Especially excess heat from industrial and
service sector facilities is an interesting source since its potential has
already been proven to be highly significant, with some researches showing
that it could cover the heat demand of the entire residential and service
sector in Europe. However, most analysis of its utilization in district
heating are not done on the hourly level, therefore not taking into account
the variability of its availability. For that reason, the main goal of this
work was to analyse the integration of industrial excess heat into the
district heating system consisting of different configurations, including
the zero fuel cost technologies like solar thermal. Furthermore,
cogeneration units were a part of every simulated configuration, providing
the link to the power sector. Excess heat was shown to decrease the
operation of peak load boiler and cogeneration, that way decreasing the
costs and environmental effect of the system. However, since its hourly
availability differs from the heat demand, thermal storage needs to be
implemented in order to increase the utilization of this source. The
analysis was performed on the hourly level in the energyPRO software.
Improvements to the characteristics of a centrifugal pump through the addition of a vortex rotor were investigated both experimentally and with computational fluid dynamic (CFD) analysis. The idea behind that improvement is in creating so-called coherent structures of eddies and turbulence in the peripheral area of the vortex rotor mounted at the back side of centrifugal rotor. Research on the energy transformations in the centrifugal vortex pump in this work was carried out using numerical simulations of the flow in the centrifugal and the centrifugal vortex pump. Measurements of relevant parameters that describe the performance of pumps, at their physical models, were gained from experiments. The measurement results were used as experimental validation of numerical simulations. In contrast, flow visualization derived from the numerical simulation was used to interpret measurements. In deriving the experimental procedure, special care was taken with the flow measurements. The reason for this is in the fact that the flow measurements had the biggest influence on the overall measurement uncertainty. However, flow measurements were the most demanding with regards to the experiment design and in taking the measurement readings. This experimental-CFD research made it possible to undertake an assessment of vortex rotor contribution on the head of the centrifugal vortex pump. The influence of the vortex rotor on the efficiency of the centrifugal vortex pump was investigated by comparing it with the efficiency of the centrifugal pump with the same geometry. An analysis of the flow structure was conducted in order to better understand the energy transformations that are the result of the interaction between the flow from the channels of the centrifugal part of the centrifugal vortex rotor and vortices formed at the vortex part of the centrifugal vortex rotor as well as their interactions with the stator. It was shown that this additional energy significantly increases pump head while increasing pump stability. This synergetic work has demonstrated that while vortex rotor gives additional energy to the fluid particles, that did not enter stator due to the energy lack by changing their momentum; at the same time, some of the kinetic energy contained in the vortex rotor induced vortices is also added to those fluid particles.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.