Principle: lighter, simpler, less work

This post is part of a series on the principles of energy reduction.


Simple systems, that do less, and cause fewer changes from their natural state, use less energy.

Consequences

This is another argument against motor cars. Cars are

• large and heavy: compare the weight of the car with the typical weight of their occupants and cargo,
• complicated: these days, cars are not really serviceable or fixable -- replacement parts are ordered from the manufacturer and the original is thrown away

Similarly, air-conditioning is so expensive because it is artificially maintaining a space at a temperature different from its environment, which requires a lot of work.

Another way of expressing this idea is that human-built systems should work with, instead of against, natural systems as much as possible.


This post was written by Angus Wallace, and first appeared on guesstimatedapproximations.blogspot.com

Principle: use the lowest form of energy possible

This post is part of a series on the principles of energy reduction.


Some kinds of energy are harder to get/make than others. High-grade energy, such as electricity and petrol, are very hard to produce and thus have great effects on the natural systems that support us. Thus, it's beneficial to use low-grade energy where possible, and avoid high-grade energy.

An approximate heirarchy is, from lowest (on the left) to highest (on the right) grade:

Heat << Fuel << Movement << Electricity

This means that it takes a lot of heat energy to make movement energy [1], and a lot of movement energy to make electricity (ie. a lot of energy is wasted at each stage. Generally speaking, a lot of heat energy has been use to make the electricity we have in our homes. If we then use that electricity to produce heat, we have wasted a lot of energy.

How to optimise this

We can use heat energy to heat. An excellent example of this is solar hot water which uses heat from the sun to directly heat water (a process that otherwise uses considerable amounts of fuel or electricity). Similarly, heat from the sun can be used to heat our houses (using either passive-solar [2] or active solar space heaters [3]) -- this saves a lot of fuel and/or energy. Solar heat can also be used directly for cooking via a solar oven [4].

A more subtle point is that if you have solar-heated hot water, and want a cup of tea, put solar hot water in the kettle and boil that.

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[1] For example, the internal combustion engine in our car uses fuel to create movement. It does this at about 25% efficiency [5]. This means that it takes for units of fuel energy to produce one unit of movement energy.

[2] en.wikipedia.org/wiki/Passive_solar_building_design

[3] www.dummies.com/how-to/.../how-to-build-a-solar-space-heater.html

[4] en.wikipedia.org/wiki/Solar_cooker

[5] http://en.wikipedia.org/wiki/Engine_efficiency#Gasoline_.28petrol.29_engines



This post was written by Angus Wallace, and first appeared on guesstimatedapproximations.blogspot.com