Energy-Efficient Address-Generation Units and Their Design Methodology

2011 ◽  
pp. 317-351
Keyword(s):  
Energy Efficient ◽  
Design Methodology ◽  
Address Generation

Must attic ventilation be preserved in energy retrofits?

2019 ◽  
Vol 37 (4) ◽  
pp. 461-472
Author(s):  
William Rose
Keyword(s):  
Vapor Pressure ◽  
Energy Efficient ◽  
Design Methodology ◽  
Air Leakage ◽  
Content Type ◽  
Buoyancy Flow ◽  
Spreadsheet Model ◽  
Radiation Exchange ◽  
Moisture Performance ◽  
Ashrae Standards

Purpose The addition of thermal insulation into attics along with air-tightening of the ceiling plane is a common first step in making homes more energy efficient. Attic ventilation was introduced decades ago on the assumption that air leakage across the ceiling was inevitable and not correctible – this was before the era of spray-applied foams. Often attic ventilation is provided at roof eaves, and ensuring good insulation in their location is critical to avoid cold corners in the rooms below. So may vents be blocked in the course of energy retrofits? The paper aims to discuss this issue. Design/methodology/approach This study consists of a simple spreadsheet model of attic performance. The model is built using material from ASHRAE Handbook Fundamentals and ASHRAE Standards. It includes: Glaser calculations for temperature, vapor pressure and vapor pressure excess; radiation exchange – solar and sky; buoyancy flow assumption for leakage from indoors; wind flow assumption for leakage from outdoors; and change in attic air RH as assumed indicator of change in sheathing moisture performance. Findings The model results show that lowered moisture contributions across air-tightened ceilings may compensate effectively for added insulation (which lowers the attic air temperature) and reduced moisture dilution from attic ventilation. Originality/value These results provide support for the policy of allowing attic ventilation reductions that are proportionate to ceiling air leakage reductions as part of weatherization efforts. Given the limitations of the model, continued field observations remain critical.

Energy consultants calculating sustainability for residential buildings

Facilities ◽  
2019 ◽  
Vol 37 (11/12) ◽  
pp. 825-838 ◽  
Author(s):  
Roger Andre Søraa ◽  
Håkon Fyhn ◽  
Jøran Solli
Keyword(s):  
Design Process ◽  
Energy Efficient ◽  
Design Methodology ◽  
Residential Buildings ◽  
Qualitative Interviews ◽  
Implementation Process ◽  
Building Sector ◽  
Content Type ◽  
Practical Implications

PurposeThis paper aims to investigate the role of a particular energy calculator in enhancing the energy efficiency of existing homes by asking how this calculator was developed and how it is domesticated by craftspeople working as energy consultants.Design/methodology/approachThe study is based on qualitative interviews with users and producers of the energy calculator (n= 22), as well as participation in energy consultation training.FindingsThe paper finds that, in the energy calculator, there is a striking lack of connection between the domestication and script because of lack of energy consultants’ involvement in the design and implementation process.Practical implicationsThe enrolment of energy consultants as energy calculator users earlier in and throughout the design process could be valuable in making the transition to an energy-efficient and environmentally friendly building sector.Social implicationsThe paper argues for recognition of the role of energy consultants, especially craftspeople, as participants in the design process for tools of governance. This is a call to acknowledge the value of particular skills and experiences possessed by craftspeople doing home consultation.Originality/valueBy understanding the intricate developer–user synchronicity in tools developed for upgrading the building sector, energy mitigation can be made more effective.

DC-link voltage selection for a multi-MW wind turbine

2014 ◽  
Vol 33 (5) ◽  
pp. 1722-1740
Author(s):  
Poopak Roshanfekr ◽  
Torbjörn Thiringer ◽  
Sonja Lundmark ◽  
Mikael Alatalo
Keyword(s):  
Wind Turbine ◽  
Energy Efficient ◽  
Design Methodology ◽  
Synchronous Generators ◽  
Maximum Torque ◽  
Voltage Level ◽  
Content Type ◽  
Permanent Magnet Synchronous Generators ◽  
Selection For ◽  
Maximum Torque Per Ampere

Purpose – The purpose of this paper is to investigate how the dc-link voltage for the converter of a wind generator should be selected, i.e. to determine the losses in the generator and the converter when using various dc-link voltage levels. Design/methodology/approach – To presents the efficiency evaluation of 5 MW wind turbine generating systems, two 5 MW surface mounted permanent magnet synchronous generators (PMSG) with medium and low rated voltage is designed. A two-level transistor converter is considered for ac/dc conversion. Three different dc-link voltage levels are used. By using these voltage levels the PMSG is utilized in slightly different ways. Findings – It is found that the system with the lower voltage machine has slightly higher annual energy efficiency compare to the higher voltage system. Furthermore, it is shown that the best choice for the dc-link voltage level is a voltage between the minimum voltage which gives the desired torque and the voltage which gives Maximum Torque Per Ampere. Originality/value – A procedure as well as investigations with quantified results on how to find the highest complete drive system efficiency for a wind turbine application. Based on two given PMSG, the most energy-efficient dc-link voltage has been established.

scholarly journals Evaluating the Impact of Architectural Decisions on the Energy Efficiency of FDCT/IDCT Configurable IP Cores

2012 ◽  
Vol 7 (1) ◽  
pp. 23-36
Author(s):  
Vinícius Dos S. Livramento ◽  
Bruno G. Moraes ◽  
Brunno A. Machado ◽  
Eduardo Boabaid ◽  
José Luiz Güntzel
Keyword(s):  
Energy Efficiency ◽  
Energy Efficient ◽  
Design Methodology ◽  
Building Blocks ◽  
Total Power ◽  
Mobile Multimedia ◽  
Battery Lifetime ◽  
Minimum Latency ◽  
Ip Cores ◽  
The Impact

The development of mobile multimedia devices follows the platform-based design methodology in which IP cores are the building blocks. In the context of mobile devices there is a concern of battery lifetime which leads to the need of energy-efficient IP cores. This paper presents four energy-efficient FDCT/IDCT configurable IP cores. These architectures are based on Massimino’s algorithm, which was chosen due to its high accuracy and parallelism. The four architectures were built by combining fully-combinational or pipelined datapaths, using either a single or two 1-D DCT blocks with a transpose buffer that assures the optimal minimum latency of eight cycles. Synthesis results for 90nm showed that our most efficient architecture, which uses two pipelined 1-D blocks, achieved 250 MHz as maximum frequency at a total power of 14.03 mW. Such frequency was enough to process 16x 1080p@30fps videos in real time (nearly 2 GigaPixels/s). Comparisons with related work, in terms of energy efficiency (μJ/MPixels), revealed that our most energy-efficient architecture is at least 2 times as efficient as other DCT architectures. Moreover, the four designed architectures were also synthesized by using common low-power techniques. These results showed that pipelined versions at high throughput tend to take more benefit from using Low-Vdd and High-Vt combined than the combinational ones, thus becoming the most energy efficient.

Enabling energy-efficient renovation: the case of vertical extension to buildings

2019 ◽  
Vol 19 (1) ◽  
pp. 2-14 ◽  
Author(s):  
Rikard Sundling ◽  
Åke Blomsterberg ◽  
Anne Landin
Keyword(s):  
Life Cycle ◽  
Environmental Impact ◽  
Energy Efficient ◽  
Design Methodology ◽  
Data Gathering ◽  
Low Energy ◽  
Content Type ◽  
Vertical Extension ◽  
Profit Analysis ◽  
Energy Plus

Purpose This paper is based on a study of six similar buildings built in Gothenburg, Sweden, in 1971, which were in urgent need of renovation. A life cycle profit analysis shows how four competing concepts were evaluated to find a financially viable renovation concept; additionally, the environmental impacts of these renovation concepts using a life cycle assessment are presented. Design/methodology/approach Four renovation concepts are compared to find the most appropriate concept, namely, minimalist, code-compliant, low-energy and low-energy plus vertical extension concepts. The methods used for comparison are life cycle profit analysis and life cycle impact assessment; the methods used for data gathering included site visits, interviews, document study, co-benefits study and energy simulation. Findings The findings show that vertical extension supported the energy-efficient renovation of the buildings and that the combination of low-energy and the vertical extension had the highest return on investment and the lowest environmental impact. The selected concept for renovating the remaining five buildings combined was the low-energy plus vertical extension. Additional benefits from vertical extension include more apartments in central locations for the housing company, a wider variety of apartment layouts and a wider range of tenants. Drawbacks include increased use of infrastructure, green space and common appliances, as well as gentrification. Originality/value This study shows how a vertical extension can financially enable an energy-efficient renovation and further lower its environmental impact. Benefits and drawbacks of densification are also highlighted to better understand the implementation of vertically extending a building.

Green publishing with green technologies

2012 ◽  
Vol 30 (3) ◽  
pp. 381-383 ◽  
Author(s):  
Katja Metz ◽  
Michael Seadle
Keyword(s):  
Energy Efficient ◽  
Design Methodology ◽  
Energy Sources ◽  
Energy Costs ◽  
Green Product ◽  
Electronic Publication ◽  
Green Technologies ◽  
Content Type ◽  
Dark Green ◽  
The Impact

PurposeIf libraries truly want to be ecologically responsible, they need also to consider the impact of book and journal production on the environment. This paper seeks to address this issue.Design/methodology/approachThe methodology looks at energy consumption in journal production.FindingsElectronic publication does not produce a perfectly green product, but more of a dark green one with many aspects where energy costs could be saved. A genuinely ecologically friendly publication process requires conscious planning and determination.Originality/valueUsers can stop demanding paper as well as electronic copies, and can also choose more energy‐efficient hardware and energy sources.

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