What’s the most environmentally friendly way to stoke your woodstove? Johannes Ludvig Zachrisson Daae worked on this question as part of his PhD. Image: Maren Agdestein, NTNU

Saving energy through environmentally friendly design

Have you ever used a water boiler to make yourself a cup of tea, but boiled enough water for two cups? Then you wasted energy. But good design can help.

Simple design changes may be enough to make everyday items much more environmentally friendly.

Have you ever had trouble getting the airflow to your woodstove just right, so that it will burn correctly? Then you’ve not only wasted energy, but also created more particulate matter and greenhouse gases than you would otherwise.

A few simple design changes could help us make smarter decisions. Johannes Ludvig Zachrisson Daae recently completed his PhD at NTNU on how good design can help people use tools in the way they were actually intended.

Saved 30 percent

It doesn’t cost you personally a lot to boil a little extra water. But a study performed by the British research organization DEFRA compared the electricity bills of people who used a regular water boiler with those who used a boiler designed to avoid boiling too much water.

The electricity wasted every year in overfilled water boilers in England is equivalent to the amount of electricity used annually on street lights in England.

The electricity wasted every year in overfilled water boilers in England is equivalent to the amount of electricity used annually on street lights in the country.

The study concluded that the improved design reduced energy consumption by 30 per cent. If all Britons swapped out their water boilers for the improved boiler, energy consumption in England could be reduced by 1.26 TWh/year. This number might not means much to you, but it is equivalent to the amount of electricity used to light all of England’s streets annually.

Small savings can add up to a lot.

As people grow more environmentally conscious, small energy savings have received more attention. Greater energy consumption creates more pollution and increased environmental impacts. For businesses, the energy efficiency of a product has become a competitive selling point. Developing products with energy efficiency in mind has the potential to create larger energy savings from small investments.

Two methods

Design can control the way a product is used by giving the user more or less control of how the product is used.

At one end of the design spectrum is giving the user complete freedom as to how they use a product. This freedom may be dictated by instructions, for example on how much dishwasher detergent to put in a dishwasher, or feedback, such as a meter showing how many litres of gas a car burns per 10 km driven.

At the other end of the design spectrum is giving the user no choice as to how they use the product. The user is then forced to behave a certain way. An example of this is a speed bump that forces you to slow down, or automatic systems like a key card holder in a hotel room that also controls the lights. When you take the card out of the holder, the lights automatically turn off.

In between these two extremes lie a variety of ways to make a consumer behave a certain way.

The goal is to make good behaviour easier, like presized dishwasher detergent tablets, or to make the undesirable behaviour harder, like ATMs that return your credit card before your money, so that you won’t forget the card.

The optimal amount of control to give the user depends on the user and the situation the product is used in. In his PhD, Daae has focused on how to help designers make good decisions about this.

Your woodstove

Daae worked on one specific example: How can wood be burned in a woodstove in the most environmentally friendly manner?

Forty-two percent of all airborne particulate matter in Norway comes from burning wood. However, given the right combustion conditions, emissions can be reduced dramatically.

The single lever had clearly designed icons that showed how to start a fire as well as how to get it to burn fast or slow. Image: Johannes Ludvig Zachrisson Daae, NTNU

The single lever had clearly designed icons that showed how to start a fire as well as how to get it to burn fast or slow. Image: Johannes Ludvig Zachrisson Daae, NTNU

Most woodstoves have two levers that control the airflow to the fire through two vents. One of the vents adjusts the airflow under the wood while the fire is being started. The second lever adjusts the airflow above the wood, which should be open after the fire has been started to allow exhaust gases to be burnt.

Ideally, both of the vents should be completely open when starting the fire. Once the fire has been lit, the airflow under the wood should be stopped while the airflow over the wood should be adjusted to achieve the ideal combustion intensity.

If you close the wrong lever, you might have trouble getting your fire to burn correctly, and the emission of greenhouse gases and particulate matter increases. To avoid this, Jøtul has made a woodstove with only one lever, where the first part of the movement controls the airflow below the wood. This makes it impossible to close the wrong vent first.

The experiment

An experiment was performed to compare a regular woodstove with two levers to the woodstove with only one lever. The single lever woodstove also had simple icons that showed how to start a fire as well as adjust it for high and low intensity burning.

Two test groups of 10 people each were asked to use both of the woodstoves. None of the groups were told how the woodstoves worked.

Half of the group that used the woodstove with only one lever noticed the icons and were able to use it correctly immediately, resulting in one-third less particulate matter emissions than the group using the woodstove with two levers.

The researchers could also see that the woodstove with one lever had burnt better, because the glass doors were clean after the ten testers had used it. The glass door on the conventional woodstove with two levers was black with soot after the trial.

«This shows how the right design can have big consequences, even when the user isn’t told how to use the product», says Daae.