Jun 13 2007

Breakeven Analysis Calculator

Justin | Category: Appropriate Technology | 0 Comments

In response to an energy conservation challenge initiatied by BC Hydro, our home has set a goal to use 15% less power this year. Using less electricity is going to be a challenge as we have already done all the easy things like change our lightbulbs to CFLs and fanatically turning off lights when not in use. The best candidate for upgrade are 3 fixtures from IKEA that use 4 20W Halogen bulbs each that are often on.

I think I found some bulbs that are compatible with my fixtures from LED Liquidators. I’m still waiting a response from them. I found a useful tidbit of information comparing the approximate lumens from LED bulbs to traditional halogen bulbs:

12 White LEDs = 7 W
24 White LEDs = 14 W

I wanted to figure out how long it would take to breakeven on upgrading all 12 lightbulbs to LEDs. Plus I thought it would be good to calculate what sort of energy savings I could expect from the purchase. To solve the problem, I created a little Excel speadsheet to crunch the numbers. Please download and test away. The BOLD values are editable. If anyone finds any flaws in my logic please leave a comment and I will update the spreadsheet.

References

Jun 12 2007

Ingredients for Choise Compost

Justin | Category: Compost | 0 Comments

After a little hunt for tips on optimizing the composting process, I found a short article which covers dimensions and ratios to a useful degree of detail. Below is an excerpt from the compost article.

Ingredients for the compost heap (no matter what method is used) are :

Organic materials – anything that has been alive can be composted! – but like making a cake, there needs to be some balance in the ingredients. The two broad categories of compost materials are high-Carbon (woody, brown, dry) to high-Nitrogen (fresh, wet, green). The microbes that work in the compost digester need a starting ratio of approximately 30 Carbon to 1 Nitrogen to make protein (ie their body mass) – thus as good heap designers, this is what we should be aiming for as an overall ratio. If you want to start getting really technical, you can analyse the compost ingredients. As each have their own balance of C/N, the overall ratio of the assembled heap needs to be adjusted accordingly (see table).

Material C/N ratio

  • Sawdust 450
  • Paper 150
  • Straw 100
  • Leaves 60
  • Fruit wastes 35
  • Lawn clippings 20
  • Food wastes 15
  • Weeds 19
  • Chicken litter (typical) 10
  • Cow manure 12
  • Chicked manure (no straw) 7

References

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