Energy Use at Home

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Comparing Energy and Heat Units

Keywords: BTU, cost, energy, greenhouse gases, oil barrel, quad, R-value, thermal conductivity, thermal resistance, unit conversion, Watts

How do I compare heat and energy values given in different units?

A look at how to compare the costs of natural gas, gasoline and electricity and how to convert between various heat units including R-values, U-values, BTU/h, W and more.

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6 years 46 weeks ago

Cool Roofs

Keywords: albedo, carbon dioxide, emission, energy, surface temperature

Can painting our roofs white offset tonnes of CO2 emissions??

In this article, we look at how we can save energy, reduce the Earth’s surface temperature and offset carbon dioxide emissions just by making our roofs and pavements a lighter colour!

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6 years 41 weeks ago

Cycling and Showering

Keywords: cycling, energy use, heat capacity, showering

Are cycle commuters, who take an extra shower, doing more damage to the environment than those who commute by car?

A recent letter to the Vancouver Sun claimed that commuting by bicycle was worse for the environment than commuting by car. The reason given was that if a cycle-commuter takes an extra shower at work (because cycling makes you sweaty), that burns the energy equivalent of a litre of gasoline, which is more than a car would burn on an average commute. Fact or rubbish?

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7 years 1 week ago

Energy and Power

Keywords: definition, energy, types, useage

What is energy? Why is it such a useful concept? How does it relate to power?

Energy is the capacity to do work (both are measured in Joules). Power is the rate at which energy is transformed from one state to another, often from a stored state into work (a Joule of energy transformed per second is a Watt of power). Subsistence living requires about 200 W per person. Western living requires about 10 kW per person. Humankind currently uses about 12.5 TW of power, most from fossil fuels. Ten billion people living a western lifestyle (the not-impossible goal of many futurists) would require 100 TW of power.

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5 years 40 weeks ago

Energy Efficiency and the Jevons Paradox

Keywords: consumption, efficiency, energy, jevons, solid state lighting

Will increasing efficiency really reduce energy consumption?

Increases in energy efficiency have been shown to increase, rather than decrease, consumption.

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6 years 28 weeks ago

Fan Efficiency

Keywords: efficiency, electric fan, power

How can we measure the efficiency of an electric fan?

When you're out shopping for an electric fan, it might be a good idea to look for one that not only keeps you cool, but keeps your energy consumption low, too. Using an anemometer, Kill-A-Watt meter and a little bit of math, you can figure out how efficient your fan really is.

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4 years 32 weeks ago

Heat Balance in the Human Body

Keywords: calories, energy, energy use, evaporation, metabolic rate, power, sweat, thermal radiation, thinking

How much energy does our body use? How do we keep cool when it is really hot out? Can we justify eating more when studying?

Treating the human body as a thermodynamic system, with food energy going in and heat flow due to radiation, convection, evaporation and conduction, we can see how we can maintain a constant core temperature in a huge variety of environmental conditions.

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6 years 40 weeks ago

Heating Efficiency

Keywords: efficiency, electric, energy, gas, power

Which is better: gas or electric heat?

Calculating or measuring efficiency means tracking the power all the way from source to end-user.

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6 years 35 weeks ago

Home Heating

Keywords: conduction, cooling, heat exchange, heat loss, heating

Where are these houses losing the most heat to the environment? The picture on the left is taken with visible light, that on the right is taken with infrared light with a wavelength of about 10 μm.

An example of how to model the heating and cooling of thermal systems, including a look at some of the issues surrounding the heating and cooling of buildings.

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7 years 1 week ago

Light Bulb Efficiency and Hand Crank Energy Generation

Keywords: breadboard, circuit, efficiency, electricity generation, energy, energy conversion, Lend an Experiment (LEx), lighting

What does it really take to power a light bulb?

This activity is part of the LEx (Lend an Experiment) Climate Kit. Students compare the power consumption of incandescent and LED bulbs through the use of hand crank generators and a simple circuit. Concepts include the conversion of mechanical to electrical energy, power and efficiency, and measurement estimation. There is an option to also investigate the efficiency of the hand crank generator.

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1 year 35 weeks ago
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