energy efficiency

When adopting energy saving bulbs, in most cases owners, managing agents and residents of commercial buildings are more concerned with reducing power consumption – with the ultimate goal being the reduction of electricity costs. However, this overlooks another important component, which consumes just as much power, the HVAC system. Babalwa Bungane reports.

According to Sustainable Energy Africa (a not-forprofit organisation promoting equitable, low carbon, clean energy development) in fully air conditioned buildings the HVAC component ranges between 30 and 60% of the building’s overall energy use. In addition, lighting takes up between 20 and 30% of energy consumption. On the other hand, a Commercial Buildings Energy Consumption Survey (CBECS), conducted in 2012 by the US Energy Information Administration, found that 17% of all electricity consumed in US commercial buildings was for lighting. The survey argues that the advent of new lighting technologies and changes to lighting efficiency standards have contributed to steep reductions in the percentage of electricity used by commercial buildings for lighting in the US.

In terms of new lighting technologies, a Navigant Research report, Market Data: Intelligent Lighting Controls, analyses the growth of networked lighting control systems across all building types globally. Intelligent lighting systems comprise multiple lighting fixtures such as occupancy sensor, timer, and daylight sensor connected in a network to provide automatic control of lighting levels to meet users’ needs. The research firm states that market revenue is expected to grow at a 14.3% compound annual growth rate between 2017 and 2026; with building codes and standards being the leading driver in the lighting controls market.

Another energy efficiency movement concerned with encouraging green building professionals to prioritise energy efficiency and use renewable energy in their planning was launched last year by the World Green Building Council (WorldGBC) in London. The initiative, titled Advancing Net Zero, is a global project that aims to ensure that all buildings are ‘net zero’ carbon by 2050. Green Building Council Brasil (GBC Brasil) has already adopted this initiative. “We will be rewarding the best buildings in the market which demonstrate excellence in planning, integrated project conception, team communication, automation, technology, renewable energy stimulation, occupant awareness and excellence in the operation,” said Felipe Faria, Executive Director of GBC Brasil and Chair of WorldGBC’s Americas Regional Network.

The Green Building Council of South Africa (GBCSA), as part of this programme, also launched a net zero programme in July 2017, including carbon, water, waste and ecology, which will allow projects to be independently certified as net zero or net positive.

In line with promoting energy efficiency standards, in 2011 the South African government published the South African National Building 10400–XA Regulations (SANS 10400-XA), which is aimed at environmental sustainability and energy usage in buildings. SANS 10400-XA is purely focused on energy consumption and maximum energy demand for new buildings or major refurbishments.

Thus far, many businesses have effectively incorporated lighting efficiency products and standards – driven by their affordability and implementation with little disruption to the business day-today operation, explains Manfred Braune, Executive Director: Certifications at GBCSA.

Meanwhile, incorporating energy efficient HVAC systems requires significantly more investment in terms of planning and capital cost, but the cost savings from energy reductions can be significant, Braune told ESI Africa. “Often, a barrier to changing HVAC systems is the lease agreement where in many cases the landlord is the owner of the HVAC system and doesn’t want to over-capitalise on the property, whilst the tenant has to pay for the cost of energy consumed, and so the landlord doesn’t benefit from the savings,” Braune says, adding: “A solution is where landlords and tenants amend the lease to allow for shared savings when the landlord invests in more efficient equipment. This can be called a green lease.”

According to GBCSA, a green lease is a term that describes a document for negotiating green building attributes between the owner and the tenant of a building, and is typically an amendment or addition to a current lease agreement. The document is basically a vehicle for both parties to unpack the shared benefits of ‘going green’ and lay out certain contractual lease obligations between a landlord and a tenant of a building that require or encourage the adoption of environmentally friendly practices.

In general, green buildings invest more in making the building more efficient, often focusing on the buildings’ systems including HVAC. While it is still challenging to incorporate both lighting and HVAC in the design or refurbishment of buildings, Braune suggests that in South Africa owners should adhere to the two key standards, namely:

• SANS 10400 Part XA -legislated minimum standard for energy efficiency for new buildings and major refurbishments

• Green Star for new buildings sets out a standard to exceed the legislated minimum

Taking all of these new initiatives and improvements of energy and lighting efficiency standards into consideration – the efficiency of energy use in commercial buildings requires collaborative efforts between architects, mechanical and electrical engineers and their clients to achieve best results. ESI

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