Since posting A Tale of Rechargeable Batteries, the PowerEx charger has earned its keep. Not only does it restore NiMH batteries that were no longer taking an adequate charge from a regular 'quick charger', it also allow me to accurately determine the capacity of NiMH batteries so that they can be matched into sets such that one battery does not become 'the weak link'.
The PowerEx charger also appears to be useful in diagnosing the 'charge lifetime' of batteries. I used 6 AA NiMH batteries of matched capacity in a label printer that gets intermittent usage. When the printer stopped working, I did a normal recharge cycle. Since the 6 batteries were in series, they should all have discharged by the same amount. However, the PowerEX reported varying recharge amounts from 500 mAh to 2000 mAh. Given that all the batteries started with the same capacity, my suspicion is that some were 'self-discharging' at a rate higher than normal. All NiMH batteries will lose their charge over time - quality issues during manufacturing or breakdown of the internal battery components can accelerate this process such that the batteries quickly discharge even if not used.
In this case, I may have matched the 6 batteries in terms of initial capacity, but clearly not in terms of their ability to hold a charge. Of the 6 batteries, the PowerEx charger results suggested that four should either be relegated to recycling or only used in high-draw devices where self-charge is less of an issue.
REGREEN is an initiative by the American Society of Interior Designers' Foundation a d the U.S. Green Building Council to develop:
Characteristics include:
"best practice guidelines and targeted educational resources for sustainable residential improvement projects. This program will increase understanding of sustainable renovation project practices and benefits among homeowners, residents, design professionals, product suppliers and service providers to build both demand and industry capacity."
- a whole-house, systems-thinking approach, focusing on "how systems or the whole building work together to reduce environment impacts" through "cross-listing of strategies by project and environmental category"
- integration of all building professions, by combining "content, resources and case studies that tie together best-practice design and construction"
- recognition that a green project must first be a quality project, and that "the beauty of a building or project ... is the starting point for durability"
- recognising the importance of designing for the specific climate and site
- emphasising the importance of decisions made at the very beginning of each project
Link: Scientist who invented "virtual water" wins prize
The Stockholm International Water Institute awarded Professor John Anthony Allan (University of London, Britain) the 2008 Stockholm Water Prize for introducing the concept of "virtual water", a calculation method that takes into account the water embodied in foods and industrial products throughout their lifecycle. For example, the 140 litres of water consumed to grow, process, package and ship the coffee beans required for a cup of water far outweighs the water that goes into the coffee maker.
Wikipedia has a synopsis of the "virtual water" concept and lists the embodied water in a range of agricultural, household and industrial products. For example:
- 1 kilogram of beef: 15,000 litres of water
- 1 kilogram of jeans: 10,850 litres of water
- a 1,100 kilogram car: 400,000 litres of water
- green water: rainwater evaporation
- blue water: surface or ground water evaporation
- grey water: water the becomes polluted during the process
Although "virtual water" can be used as a way of assessing the impact of different products on water resources, Allan's developed the concept to explain why water scarcity in regions such as the Middle East had not led to 'water wars (Watersheds and Problemsheds: Explaining the Absence of Armed Conflict Over Water in the Middle East). Imports of products, particularly agricultural produce with a high embodied water content can represent a significant import of "virtual water", reducing the stress on local water supplies. According to Virtual Water, 15% of the world's water usage is for export, with USA, Canada and Thailand the leading exporters and Sri Lanka, Japan and Netherlands the leading importers. Allan argues "virtual water" should guide policy decisions, such as allocating water to products that "bring a sound return to water as well as sound returns to the economy" and increasing productive efficiency.
