6.4 Operating Energy for Buildings

 

 

6.4 Operating Energy for Buildings

As well as the embodied energy contained in the materials of a building, and that of the processes used to construct a building, the main environmental impact will be the energy used during its lifetime. The figure below shows different scenarios of energy use over a lifetime of a building compared to the embodied energy

Figure 6.4.1 Operating Energy of Buildings [see reference 5]

Figure 6.4.1 sourced from MIT opencourseware under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 United States License
http://dspace.mit.edu/bitstream/handle/1721.1/39134/1-964Fall-2004/OcwWeb/Civil-and-Environmental-Engineering/1-964Fall-2004/LectureNotes/index.htm


According to the US Department of Energy, in the USA buildings account for 37% of primary energy consumption, and 65% of electricity use. This is the biggest use, followed by industry which is 36% and transportation which is 27%. This energy use by building accounts for 30% of greenhouse gases. [see reference 5]

Energy is used in buildings for heating, ventilation, lighting and electrical appliances used within the building. The majority of the energy use is for space heating, in fact 4-7% of a developed nation's energy consumption is due to heat losses from domestic windows alone . In EC countries, at least one quarter of the domestic heating bill is due to the thermal energy loss through windows because they are the weakest thermal component in the exterior envelope. [see reference 5]

Some of this energy can be reduced through behavioural changes conducted by the residents of the buildings, such as turning the heating down, switching off lights when not in rooms, or turning electrical devices off when not in use. However a larger amount can be reduced through effective design of the building to make use of natural resources such as solar energy and effective insulation, which will be covered in the next section.

Table 6.4.1 Energy needs and sustainable solutions of a building

Need

Current Solution

Sustainable Solution

Lighting

Electric Lights fed by the grid

Daylight

Renewable energy

Heating

Mains electricity, gas

Better insulation

Cooling

Air-conditioning

Natural ventilation

(Source Ochsendorf [see reference 5])

Having briefly covered the main negative implications of the construction industry, we will now examine sustainable alternatives.