Sustainable Engineering
Sustainabilty is a wide field covering Social. Economic and Environmental improvement.
Zero Carbon Engineering works primarily in the field of Environmental and Economic improvement.
We focus on a given business area and its use of resources and ask:-
- Do we have to use the resource at all or can it be avoided?
- Can we use the resource more efficiently?
- Can we reuse or recycle a resource?
- Can we use a resource that is less polluting?
However whatever is proposed has to make good business sense to ~Board Members and Shareholders.
"Do We have to use it at all": In the example above, daylighting panels let in natural light and light sensors turn the LED lighting down, so only as much electricity is used as is needed to supplement natural light. Other options are behavioural programmes to encourage people to turn things off, or automation to turn things on and off automatically, as they are needed.
As an example of "using something more efficiently", the two GU10 lamps to the left come from the same manufacturer.
The halogen unit use 50Watts to generate 340 lumens. It has a life of 2,000hours.
The LED unit uses 5.5 watts to generate 360 lumens. It has a life of 25,000hours.
Over the life of the LED lamp (assume 6 years) you will have replaced the halogen unit 12 times. On top of that the electricity will have cost you 9 times more. At February 2018 costs that adds up to £117 saving per LED GU10 over about 6 years. When looking at new technologies it is important to consider life cost and not just capital cost.
In terms of "recycle and reusing resources", recycling of plastics and card are common place in both the public and private sector.
Wood waste can be recycled into wood pellets and as such used for heating and hot water, and also as part of Biomass-CHP to generate power and heat.
This is sustainable as it avoids burning fossil fuels - replacing them with carbon that is already in the natural cycle.
It is possible to produce gas either for heating or making electricity from food waste or animal and vegetable waste from farming. Again this avoids the burning of fossil fuels but also where decomposition of these product produce methane with a GWP of 25 (DEFRA 2017), this captures the methane and through combustion converts it to CO2 with a GWP of 1.
In terms of "using resources with less environmental impact" a significant amount of the UK's electrical generating capacity has been converted to solar, wind and it is possible to generate power using biofuels.
Biofuels - based on wood or vegetable oils - can be used to run heating rather than burning gas.
As an alternative it is also possible to raise the effiency of using electricity for heating by making use of ground or air source heat pumps. This uses electricity to move and intensify heat from the environment for heating.
With the above in mind, it is necessary to change ones mindset away from the "we'll take raw resources - be they mineral, vegetable or otherwise - shape them into something we need, and when it's used or broke and there's a waste product we'll throw it away".
We need to consider the value we can take out of waste by recycling and reuse.
As a good example - in the early days of LED design, GE developed spotlights with LED chips that were 80 lm/watt. They had the foresight to make the chips replaceable so that when newer more efficient chips came along, it was possible just to replace the LED chip and the circuit board it was mounted on - rather than the whole spotlight.