Energy Use at Home

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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?

7 years 18 weeks ago

Turn the Heat Off!

Keywords: energy loss, heat loss, power

Do you save more energy by leaving the heat on at night or by turning it down and reheating the house the next day?

We examine the benefit of turning off the heat when you go out.

7 years 18 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.

7 years 18 weeks ago

Thermal Radiation

Keywords: black body radiation, infrared, thermal radiation

All bodies emit radiation. So why don't we all shine in the dark?

Thermal radiation is a crucial part of our macro and micro environments. Although invisible to the eye it can be measured and imaged.

7 years 14 weeks ago

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.

7 years 10 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!

7 years 5 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.

7 years 4 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.

6 years 52 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.

6 years 45 weeks 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.

6 years 4 weeks ago
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