scholarly journals Improved energy performance of small-scale pneumatic dryers used for processing cassava in Africa

2016 ◽  
Vol 151 ◽  
pp. 510-519 ◽  
Author(s):  
Marcelo Precoppe ◽  
Thierry Tran ◽  
Arnaud Chapuis ◽  
Joachim Müller ◽  
Adebayo Abass
Keyword(s):  
Energy Performance ◽  
Small Scale

Numerical Simulation of the Internal Flow of a New-Type Shaft Tubular Pumping System

2011 ◽  
Author(s):  
Honggeng Zhu ◽  
Longyang Dai ◽  
Rentian Zhang ◽  
Guoxian Zhu ◽  
Linbi Yao ◽  
...  
Keyword(s):  
Flood Control ◽  
Energy Performance ◽  
Structural Features ◽  
Water Diversion ◽  
Small Scale ◽  
Pumping Station ◽  
Pumping System ◽  
Pumping Stations ◽  
Low Head ◽  
New Type

The structural features of a pumping system will directly affect the investment of the pumping station and its pumping efficiency. In the design and construction of low head or extra-low head pumping stations, bulb tubular pumping system and shaft tubular pumping system are widely adopted. So far all the 5 large tubular pumping stations finished or under construction took the form of rear type bulb tubular pumping system (bulb is arranged inside the discharge passage) in China’s Eastern Route Project of South-to-North Water Diversion. However, front type shaft tubular pumping systems (shaft is arranged inside the suction box) are more widely used in city flood-control pumping stations, which are characteristic of large amounts and medium or small scale. To improve the reliability of city flood-control pumping stations, the authors have invented a new-type shaft tubular pumping system featuring shaft suction box, siphon-type discharge passage with vacuum breaker valve as the cutoff device, which is possessed of such advantages as simpler structure, reliable cutoff and better energy performance. Taking an real pumping station in Yancheng city of China as an example, the computational fluid dynamics method was adopted in this paper to simulate the three dimensional turbulent flow of a model new-type tubular pumping system (impeller diameter D = 0.3m, rotational speed n = 1100r/min and specific speed ns is about 1500) and predict its performance, to improve the pumping system efficiency through hydraulic design optimization. Computation results show that the efficiency of the new-type shaft tubular pumping system reached 56.0% when the design head and discharge are 1.15m and 0.326m3/s respectively, and up to 68.8% when the maximum head and relevant discharge are 1.95m and 0.296m3/s respectively, having more extensive foreground for low-head, especially extra-low-head city flood-control pumping stations.

scholarly journals Numerical and Experimental Investigations of Composite Solar Walls Integrating Sensible or Latent Heat Thermal Storage

2020 ◽  
Vol 10 (5) ◽  
pp. 1854 ◽  
Author(s):  
Enghok Leang ◽  
Pierre Tittelein ◽  
Laurent Zalewski ◽  
Stéphane Lassue
Keyword(s):  
Weather Conditions ◽  
Energy Performance ◽  
Cold Season ◽  
Experimental Investigations ◽  
Small Scale ◽  
Storage Element ◽  
Storage Wall ◽  
And Performance ◽  
Set Up ◽  
Solar Wall

This article studies a composite solar wall with latent storage (TES) designed to heat rooms inside buildings during the cold season. No numerical model of the composite solar wall is currently available in the Dymola/Modelica software library. The first objective of this work is to develop one such model. The article describes the elementary components, along with the equations that allow modeling the heat transfers and storage phenomena governing both the thermal behavior and performance of the solar wall. This model was built by assembling various existing basic elements from the software’s “Building” library (e.g., models of heat transfer by convection, radiation and conduction) and then creating new elements, such as the storage element incorporating the phase change material (PCM). To validate this solar wall model, numerical results are compared to experimental data stemming from a small-scale composite solar wall manufactured in our laboratory, and the experimental set-up could be tested under real weather conditions. After verifying the level of confidence in the model, the energy performance of two solar walls, one with a conventional storage wall (sensible heat storage) the other containing a PCM (the same as in the experiment), are compared. The result indicates that the solar wall incorporating a PCM does not in this case release any more energy in the room to be heated.

scholarly journals Evaluation of the energy performance and cost-benefit of innovative technologies in butcher’s shops

2021 ◽  
Vol 246 ◽  
pp. 05003
Author(s):  
Jeroen Lippens ◽  
Saar Lokere ◽  
Wout Barbary ◽  
Hilde Breesch
Keyword(s):  
Energy Use ◽  
Reference Model ◽  
Cost Benefit ◽  
Energy Performance ◽  
Hot Water ◽  
Small Scale ◽  
Small Contribution ◽  
Tertiary Sector ◽  
Domestic Hot Water ◽  
Innovative Technologies

The CO2 emissions and energy use of SMEs in the tertiary sector (e.g. small food and non-food shops, restaurants, offices, pubs, etc.) are high and there are few initiatives to reduce because this target group is difficult to reach due to small scale and diversity. The Flemish-Dutch TERTS project wants (1) to make the sector aware of the potential of and (2) to demonstrate energy transition and energy efficiency of innovative technologies. This paper is focussing on butcher’s shops. A reference model is made based on data of 90 existing shops in Flanders (Belgium). The energy use of the building and systems is calculated according to DIN V 15 899. The cost-benefit of various measures is calculated and compared. Results show that the main energy consumers of a butcher shop are cooling, lighting and domestic hot water, whereas heating only has a rather small contribution. There are several cooling needs: product-cooling (in walk-in freezers, walk-in coolers and the cooling counter) and cooling of the workshop. The combination of the following measures is concluded to be the most favourable and leads to a reduction in final energy consumption of 60 %: a reflective coating on the flat roof and extra roof insulation, relighting with LED, air-to-water heat pump for the generation of domestic hot water and PV panels as local energy generation.

scholarly journals Helium as a Carrier Gas in Humidification Dehumidification Desalination Systems

2011 ◽  
Author(s):  
G. Prakash Narayan ◽  
Ronan H. McGovern ◽  
John H. Lienhard ◽  
Syed M. Zubair
Keyword(s):  
Energy Efficiency ◽  
Energy Consumption ◽  
Specific Energy Consumption ◽  
Energy Performance ◽  
Small Scale ◽  
Potential Solution ◽  
Design Models ◽  
Carrier Gas ◽  
High Specific Energy ◽  
Very High

A promising technology for small scale seawater desalination is the humidification dehumidification (HDH) system. This technology has been widely investigated in recent years. Since existing HDH systems have very high specific energy consumption, the authors have previously invented several ways to increase the energy efficiency of these systems. Even for these relatively higher efficiency systems the dehumidifier is expected to be large, owing to the large thermal resistance associated with the presence of non-condensable carrier gas (air) in the system. In this manuscript, we demonstrate that changing the carrier gas from air to helium a potential solution to this problem. In addition, the energy performance of a brine heated HDH system using helium relative to those using air is analysed in detail through well established on-design models for the components in the system.

scholarly journals Energy performance comparison of two small scale combined geothermal heating plants for greenhouse heating

2020 ◽  
Author(s):  
Alexandros Sotirios Anifantis ◽  
Artur Przywara ◽  
Pawel Sobczak ◽  
Simone Pascuzzi ◽  
Francesco Santoro
Keyword(s):  
Energy Performance ◽  
Performance Comparison ◽  
Small Scale ◽  
Geothermal Heating

scholarly journals Experimental Assessment of a Multi-Variable Control Strategy of a Micro-Cogeneration Solar-ORC Plant for Domestic Application

2021 ◽  
Vol 312 ◽  
pp. 08006
Author(s):  
Diego Vittorini ◽  
Fabio Fatigati ◽  
Davide Di Battista ◽  
Marco Di Bartolomeo ◽  
Roberto Carapellucci
Keyword(s):  
High Temperature ◽  
Flat Plate ◽  
Thermal Power ◽  
Energy Performance ◽  
Hot Water ◽  
Small Scale ◽  
Domestic Hot Water ◽  
Wide Range ◽  
Electrical Generation ◽  
Operating Points

Suitability to off-design operation, applicability to combined thermal and electrical generation in a wide range of low temperatures and pressures and compliance with safety and environmental limitations qualify small-scale Organic Rankine Cycle plants as a viable option for combined heat and power generation in the residential sector. As the plants scale down, the electric and thermal output maximization has to account for issues, spanning from high pump power absorption, compared to the electric output of the plant, to intrinsically low plant permeability induced by the expander, to the intermittent availability of thermal power, affected by the heat demand for domestic hot water (DHW) production. The present paper accounts for a flat-plate solar thermal collector array, bottomed by an ORC unit featuring a sliding vane expander and pump and flat-plate heat exchangers. A high-temperature buffer vessel stores artificially heated water – electric heaters, simulating the solar collector - and feeds either the hot water line for domestic use or the ORC evaporator, depending on the instantaneous demand (i.e., domestic hot water or electric power), the temperature conditions inside the tank and the stored mass availability. A low-temperature receiver acts like the heat sink of the ORC unit and harvests the residual thermal power, downstream the expander: a dedicated control, modelled to properly modulate the mass addition/subtraction to this storage unit allows to restore the operating points of the cycle and to limit the incidence of off-design operation, via real-time adjustment of the cycle operating parameters. Indeed, the possibility of continuous ORC generation depends on (i) the nature of the demand and (ii) the amount of hot water withdrawn from the high-temperature buffer vessel. The time-to-temperature for the mass stored inside the buffer affects the amount of ORC unit activations and eventually the maximum attainable generation of electric energy. The plant energy performance is experimentally assessed, and various characteristic operating points are mapped, based on test runs carried out on a real-scale ORC pilot unit.

scholarly journals Integrated Geothermal Energy Systems for Small-Scale Combined Heat and Power Production: Energy and Economic Investigation

2020 ◽  
Vol 10 (19) ◽  
pp. 6639 ◽  
Author(s):  
Pietropaolo Morrone ◽  
Angelo Algieri
Keyword(s):  
Geothermal Energy ◽  
Energy Demand ◽  
High Efficiency ◽  
Energy Performance ◽  
Combined Heat And Power ◽  
Integrated System ◽  
Operating Conditions ◽  
Economic Viability ◽  
Small Scale ◽  
Partial Load

In recent years, an increasing interest in geothermal energy has been registered in both the scientific community and industry. The present work aims to analyse the energy performance and the economic viability of an innovative high-efficiency geothermal-driven integrated system for a combined heat and power (CHP) application. The system consists of a heat exchanger (HEX) and a transcritical organic Rankine cycle (ORC) that work in parallel to exploit a high-temperature geothermal source (230 °C) and satisfy the energy demand of a commercial centre located in Southern Italy. The ORC and HEX sub-units can operate at partial load to increase the system flexibility and to properly react to continuous changes in energy request. A lumped model was developed to find the proper operating conditions and to evaluate the energy production on an hourly basis over the whole year. In particular, a multi-variable optimisation was implemented to find the most suitable configuration and a 101.4 kWel ORC was selected while the HEX nominal power was 249.5 kWth. The economic viability of the integrated system was evaluated in terms of net present value and payback period and different operating strategies were compared: thermal-driven, electric-driven, and a mixed strategy. The latter turned out to be the best solution according to both energy and economic criteria, with electric and thermal self-consumptions larger than 90%, with no heat dumping and a payback time close to five years.

scholarly journals Comparative Analysis of Small-Scale Integrated Solar ORC-Absorption Based Cogeneration Systems

Energies ◽  
2020 ◽  
Vol 13 (4) ◽  
pp. 946
Author(s):  
Xiaoqiang Hong ◽  
Feng Shi
Keyword(s):  
Power Generation ◽  
Energy Efficiency ◽  
Organic Rankine Cycle ◽  
Rankine Cycle ◽  
Energy Performance ◽  
Primary Energy ◽  
Working Fluid ◽  
Small Scale ◽  
Cascade System ◽  
Cooling Mode

This paper aims to present a comparative study into the cascade and series configurations of the organic Rankine cycle based small-scale solar combined cooling, heating and power system for civil application. The energy performance of the systems is studied by developing a thermodynamic model. The simulation model is validated using the literature results. Analyses of the research results indicated that the cascade system can achieve maximum value of the primary energy efficiency of 13.4% for cooling and power generation under solar collecting temperature of 115 °C in cooling mode. The cascade system has more cooling output and less electricity output in cooling mode compared with the series system. In heating mode, the single solar organic Rankine cycle (ORC) operation can achieve highest primary energy efficiency of 19.6% for heating and power generation under solar collecting temperature of 100 °C. Systems with R141b as ORC working fluid show better performance than those with R123 and R1233zd(E).

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