scholarly journals Energy Savings in Desalination Technologies: Reducing Entropy Generation by Transport Processes

2019 ◽  
Vol 141 (7) ◽  
Author(s):  
John H. Lienhard V
Keyword(s):  
Energy Efficiency ◽  
Entropy Generation ◽  
Energy Savings ◽  
Technology Development ◽  
Saline Water ◽  
Forward Osmosis ◽  
Membrane Distillation ◽  
Transport Processes ◽  
Power Cycles ◽  
Entropy Generation Minimization

Desalination systems can be conceptualized as power cycles in which the useful work output is the work of separation of fresh water from saline water. In this framing, thermodynamic analysis provides powerful tools for raising energy efficiency. This paper discusses the use of entropy generation minimization for a spectrum of desalination technologies, including those based on reverse osmosis (RO), humidification–dehumidification (HDH), membrane distillation (MD), electrodialysis (ED), and forward osmosis (FO). Heat and mass transfer are the primary causes of entropy production in these systems. The energy efficiency of desalination is shown to be maximized when entropy generation is minimized. Equipartitioning of entropy generation is considered and applied. The mechanisms of entropy generation are characterized, including the identification of major causes of irreversibility. Methods to limit discarded exergy are also identified. Prospects and technology development needs for further improvement are mentioned briefly.

scholarly journals Entropy Generation Minimization for Energy-Efficient Desalination

2018 ◽  
Author(s):  
John H. Lienhard
Keyword(s):  
Energy Efficiency ◽  
Entropy Generation ◽  
Energy Efficient ◽  
Technology Development ◽  
Saline Water ◽  
Forward Osmosis ◽  
Membrane Distillation ◽  
Power Cycles ◽  
Entropy Generation Minimization ◽  
Work Of Separation

Desalination systems can be conceptualized as power cycles, in which the useful work output is the work of separation of fresh water from saline water. In this framing, thermodynamic analysis provides powerful tools for raising energy efficiency. This paper discusses the use of entropy generation minimization for a spectrum of desalination systems, including those based on reverse osmosis, humidification-dehumidification, membrane distillation, electrodialysis, and forward osmosis. The energy efficiency of desalination is shown to be maximized when entropy generation is minimized. Equipartition of entropy generation is considered and applied to these systems. The mechanisms of entropy generation in these systems are characterized, including the identification of major causes of irreversibility. Methods to limit discarded exergy are also identified. Prospects and technology development needs for further improvement are mentioned briefly.

scholarly journals Rescaling the energy label for washing machines: an opportunity to bring technology development and consumer behaviour closer together

2019 ◽  
Vol 13 (1) ◽  
pp. 51-67 ◽  
Author(s):  
Alicia Boyano ◽  
Nieves Espinosa ◽  
Alejandro Villanueva
Keyword(s):  
Energy Efficiency ◽  
Energy Efficient ◽  
Energy Savings ◽  
Technology Development ◽  
Efficiency Index ◽  
Additional Parameter ◽  
The European Union ◽  
Washing Machines ◽  
Energy Label ◽  
Energy Labelling

Abstract Washing machines have in recent years incorporated programmes that are very energy- and water-efficient, but this entails a long programme duration, often beyond 4 h. These are also the programmes that the manufactures use to define, test and declare the overall water and energy efficiency of the machines. In response to these developments, there is evidence that consumers are reluctant to use excessively lengthy programmes, even if they are aware that the programmes are more energy-efficient. This paper analyses this divergence of programme offer and programme use, which jeopardises the energy efficiency policy objectives for these appliances in the European Union (EU). The paper explores several policy measures to address this divergence, discussed in the context of the revision of the Ecodesign and Energy Labelling regulations that apply to washing machines in the EU. Three different measures are studied: the provision of information about the programme duration on the energy label, the inclusion of time as an intrinsic parameter of the energy efficiency index calculations and the setting of a programme duration cap. The paper concludes that introducing programme duration as an additional parameter of the energy efficiency index would result in the highest energy savings. However, this scenario is associated with significant uncertainties since competition among the manufacturers for a better energy label classification will not solely focus on energy efficiency aspects, and the outcome of such competition is unclear. The other two measures investigated are less effective but would also deliver savings. A programme duration cap would bring energy savings if consumers are aware of their existence and select the now shorter yet energy-efficient programmes more often. The provision of programme duration information on the energy label would also be effective but requires that consumers are able to correctly understand it.

An Analysis of Actual Energy Savings in an Indian Cement Industry Through an Energy Efficiency Index

2012 ◽  
Vol 9 (8) ◽  
pp. 829-840 ◽  
Author(s):  
R. Saidur ◽  
M. T. Sambandam ◽  
M. Hasanuzzaman ◽  
D. Devaraj ◽  
S. Rajakarunakaran
Keyword(s):  
Energy Efficiency ◽  
Energy Savings ◽  
Efficiency Index ◽  
Cement Industry

scholarly journals Minimal Monitoring of Improvements in Energy Performance after Envelope Renovation in Subsidized Single Family Housing in Madrid

2020 ◽  
Vol 13 (1) ◽  
pp. 235
Author(s):  
Fernando Martín-Consuegra ◽  
Fernando de Frutos ◽  
Ignacio Oteiza ◽  
Carmen Alonso ◽  
Borja Frutos
Keyword(s):  
Energy Efficiency ◽  
Energy Savings ◽  
Low Cost ◽  
Energy Performance ◽  
Quality Parameters ◽  
Urban Setting ◽  
Single Family ◽  
Nineteen Fifties ◽  
Environment Quality ◽  
Urban Complex

This study quantified the improvement in energy efficiency following passive renovation of the thermal envelope in highly inefficient residential complexes on the outskirts of the city of Madrid. A case study was conducted of a single-family terrace housing, representative of the smallest size subsidized dwellings built in Spain for workers in the nineteen fifties and sixties. Two units of similar characteristics, one in its original state and the other renovated, were analyzed in detail against their urban setting with an experimental method proposed hereunder for simplified, minimal monitoring. The dwellings were compared on the grounds of indoor environment quality parameters recorded over a period covering both winter and summer months. That information was supplemented with an analysis of the energy consumption metered. The result was a low-cost, reasonably accurate measure of the improvements gained in the renovated unit. The monitoring output data were entered in a theoretical energy efficiency model for the entire neighborhood to obtain an estimate of the potential for energy savings if the entire urban complex were renovated.

scholarly journals Real-World Implementation of an ICT-Based Platform to Promote Energy Efficiency

Energies ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2416
Author(s):  
Marina Dorokhova ◽  
Fernando Ribeiro ◽  
António Barbosa ◽  
João Viana ◽  
Filipe Soares ◽  
...  
Keyword(s):  
Energy Efficiency ◽  
Real World ◽  
Energy Savings ◽  
Quality Parameters ◽  
Horizon 2020 ◽  
Flexible Devices ◽  
Information And Communication ◽  
Energy Consuming ◽  
And Behavior ◽  
And Control

The energy efficiency requirements of most energy-consuming sectors have increased recently in response to climate change. For buildings, this means targeting both facility managers and building users with the aim of identifying potential energy savings and encouraging more energy-responsible behaviors. The Information and Communication Technology (ICT) platform developed in Horizon 2020 FEEdBACk project intends to fulfill these goals by enabling the optimization of energy consumption, generation, and storage and control of flexible devices without compromising comfort levels and indoor air quality parameters. This work aims to demonstrate the real-world implementation and functionality of the ICT platform composed of Load Disaggregation, Net Load Forecast, Occupancy Forecast, Automation Manager, and Behavior Predictor applications. Particularly, the results obtained by individual applications during the test phase are presented alongside the specific metrics used to evaluate their performance.

Sign in / Sign up

Export Citation Format

Share Document