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The Conservation, Efficiency and Renewable Use of Energy

Scientists have warned that global warming is one of the most urgent environmental problems that we are presently faced with. The ‘developed’ world’s dependence on fossil fuels to run economies is currently perpetuating a rise in the planets’ temperatures resulting from the powering of buildings, industries and transport systems together with various polluting activities. Scientists and environmentalists all over the world are calling for a major rethink on our present use of energy. Existing energies need to be conserved, used more efficiently and ultimately switched over to cleaner, more renewable sources of energy.

 

• Global Warming & CO2 Emissions Emissions

The ‘developed’ world is presently responsible for approximately 50% of the planet’s greenhouse gases. The construction industries, and those involved in designing building services, have a major part to play in averting the catastrophes of global warming (Ref 5).

• Certain gases in the atmosphere, known as greenhouse gases, act like the glass of a greenhouse. They allow incoming short-wave radiation to enter and warm the surface of the Earth while preventing longer-wave radiation from escaping back into space. Their increase is causing the present rise in the earth’s temperatures. This is called the “greenhouse effect.”

• The principal greenhouse gas contributing to present global warming is Carbon Dioxide (C02), and is generated from our use of electricity as well as the burning of fossil fuels to power motor vehicles. (In addition, CFC’s, HCFC’s and halons are other major greenhouse gases, which are related to the building industry).

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• Energy Conservation Energy Conservation

Strategies to promote a greater conservation of existing energy are as follows:

• Urban and landscape design:

> Cities need to reduce their reliance on the motorcar, maximizing the use and potential for       public transport, with more compact mixed-use, planning, and the concentration of                 development within existing urban areas and along transport corridors. Create attractive         and safe cycle and footpath systems.

> Minimize land-use separation, zoning and sub-division, with the integration of buildings to       facilitate a multi layering of uses while maximizing the potential for making beneficial             interconnections.

> Enhance local urban microclimates with the use of dense belts of planting to protect various     urban edges from adverse weather conditions. Planting trees, creating parkland and               localized storm water and ‘waste’ water recycling systems with the use of planting in,             around and on buildings will improve urban microclimates. In addition, planting will help in     countering the effects of air pollution and global warming by their ability to enhance air         quality and absorb excess C02.

 

• Building Design & Construction:

Consider the possibilities for the conservation and adaptive reuse of existing buildings and materials, rather than continually building new structures and manufacturing new materials. Existing structures and materials represent considerable investments in energy. Use construction techniques, which allow for recycling, dismantling and re-erection of structures and materials.

> Consider the life cycle costing of materials and products.

> Try to avoid, or use sparingly those materials known for their high-embodied energy. 

> Avoid high transport costs by using locally sourced natural building materials. Source materials and           products as close as possible to the site, while trying not to use imported products.

> Avoid designing deep plan offices, which are reliant on costly and highly energy inefficient operating       systems, such as artificial lighting and air-conditioning.

> Maximize the use of natural light. Use skylights; make use of fanlights; design light shelves to bounce         light further into spaces while also doubling up as sun shields and design courtyards and atriums to           bring light further into spaces.

> Create comfortable internal and external environments with passive solar design. Note:For more               information on Passive Solar Design, refer to Appendix D.

>  Maximize the use of natural ventilation, with windows and vents, operated by simple, user-friendly            means.

>  Use insulating materials or layers to reduce the effects of heat transfer, while avoiding thermal bridging      within the building fabric, where poor insulators provide a bridge for the easy loss, or gain of heat.

> Design for adequate sun shading to avoid the build up of excess heat in summer, while allowing for         good sun penetration during winter.

> Use double-glazing, other insulating types of glass, or insulated shutters for large glazed openings, so       as to prevent excess heat loss or gain.

> Avoid the excess use of un-insulated glazing on the cold side of buildings.

> Use draft proofing around windows and doors to avoid excess heat loss (while avoiding potential             problems with indoor air pollution – refer to chapter on healthy non-polluting environments).

> For large buildings (typically offices), avoid false ceilings, as they inhibit proper energy conservation.         By exposing the underside of a concrete floor slab, the heat rising during the day will be absorbed by       the structure and can either be flushed out at night to cool the building down in time for the next day, or     else retained during winter for heating.

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• Energy Efficiency

As part of an overall strategy to curb our reliance on fossil fuels, there is also a need to find ways of using energy much more efficiently. While investments to achieve this end may initially be higher, the longer-term effect is reduced running costs, with considerable savings both financially as well as to the environment. Some of the measures to improve on energy efficiency within the construction process are listed below:

• Use geyser blankets and pipe lagging with hot water systems. Hot water systems are usually the biggest consumers of energy in an average household and as such, fitting insulating devices provides an excellent option with retrofitting as well as when installing new geysers. In addition avoid foamed insulating materials that use CFC’s in their production. 

• Position the geyser as close as possible to its point of use. This will save energy as well as water.

• Geyser timing devices can be set to respond to a routine so as to reduce overall consumption of electricity.

• Consider using instantaneous heaters for small uses, rather than piping water from a distance away. However, these should not be used for heating larger quantities of hot water, such as in a bathroom. This will require that they draw greater Kilowatts of power, loading the peak demands for power supply.

• Use energy saving lights such as halogen or compact fluorescent lights (taking care with the placement of their transformers. 

• Use intelligent lighting systems such as occupancy sensors and lumostats.

• Specify energy efficient appliances i.e. the most energy efficient ones on the market.

• Make use of heat exchangers to recycle ‘waste’ heat.

• Consider using natural gas as a fuel as opposed to electricity as it is more efficient in its conversion of energy. Furthermore, methane also produces less CO2 when burnt than other types of fuel. It burns cleanly unlike coal, (from which most of South Africa’s power is generated) which is heavily polluting and causes problems with smog and acid rain.

• For large typically office type buildings, where passive design measures are not possible, consider the use of evaporative coolers in preference to air conditioning systems.​

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• Renewable Energy

Maximize the use of non-polluting renewable energy sources:

• Solar hot water heaters are, at present, the simplest and most highly effective means of saving energy and promoting renewable energy sources.

• Solar ovens are a simple, non-polluting way of cooking food without the use any fuel source other than what is freely available from the sun. They can be purchased or easily and cheaply built by oneself.

• Solar Ponds extract heat from specially designed salt pools for heating or power generation.

• Solar Pumps are an effective, renewable means of drawing water from one place to another for storage or use and do not require polluting batteries for their operation.

• Bio-gas Digesters are localized systems for obtaining fuel with the collection of methane gas. Methane burns relatively cleanly and furthermore, while it is a powerful greenhouse gas (contributing to approx.18% of the global warming effect; Ref: 6.) by collecting it, these systems are preventing its escape into the atmosphere. Although fairly easy to construct, these systems do require on-going maintenance and control.

• Wind pumps are used for pumping water from lower to higher levels.

• Water Turbines used on a localized scale are most effective when one has a reliable source of water that is either fast flowing or has sufficient level change to power a turbine.

• Wave Power generators have been developed, but are difficult and expensive to operate on a localized scale. Use with caution those renewable sources of energy, which can cause pollution:

• Photovoltaic cells – are panels mounted to face the sun, which are capable of generating electric power. While the technologies for these are improving all the time - 14 with the development of more efficient panels and integrated roofing and cladding systems (not yet locally available) - they still rely on heavily polluting technologies, in particular the use of batteries creating an ongoing source of toxic wastes. However if Eskom were to allow solar power producers to sell their excess electricity back to the grid, then this would alleviate the use of batteries.

• Wind Turbines – are highly effective at generating power. However unless it is possible to sell power directly to the grid, potentially polluting batteries are required. Some countries like Denmark have large wind farms that power whole towns and cities.

• Firewood is a completely renewable and sustainable energy source. However where its use is not accompanied by replanting, it will result in deforestation and the accumulation of the greenhouse gas, carbon dioxide, into the atmosphere.