ENERGY MODELLING OF A HIGH-RISE OFFICE COMPLEX IN LAGOS, NIGERIA
Energy conservation and reduction in carbon emissions is often neglected in Nigeria as commercial buildings and industries rely heavily on fossil fuel generators for power due to Nigeria’s enduring energy crises. In a bid to pioneer energy conservation in the real estate sector, a property development company (UPDC) has now completed ‘Victoria Mall Plaza II (VMPII)’ - a 15-storey office complex designed to be more energy efficient than its contemporaries. This development is perceived by UPDC and the Lagos state Government as a giant stride forward towards the conservation of fuel and power in the real estate sector. In line with this, there is need to investigate the energy performance of VMPII so that it may form part of a series of consultations, leading to the development of an energy benchmark for buildings in Nigeria.
Thus this study investigates the energy performance of VMPII, to establish if its performance matches its potential by comparing its performance with other best practice benchmarks and also give recommendations for future improvements, so that its systems and constructions may be adopted in full or in part as a notional reference for buildings in Nigeria.
The research was conducted by creating computerized thermal models of the building using IES-VE software and subsequently performing series of linked simulations. Model data was derived from a complete set of as-built drawings supplied by the project’s consultant – AIM Group based in Lagos, Nigeria. The building’s overall environmental performance was evaluated using BREEAM international bespoke procedure.Thermal analysis results show that operational annual carbon emissions stood at 699tC02 from a total annual energy demand of 2426MWh, equivalent to an annual energy use of 198Kwh/m2/yr which improves on ECON 19 energy use benchmark of 220Kwh/m2/yr for offices, but exceeds the CIBES guide F benchmark of 128Kwh/m2/yr. Sensitivity analysis reveal that improving the thermal performance of the external fabric of office buildings in Lagos, through better insulation, has minimal effect on operational energy demand.
On environmental performance, VMPII scores strong points on water, ‘health and well-being’, but lags on waste, ‘land use and economy’, materials and management, giving it a BREEAM rating of GOOD.
Feasible retrofit additions to VMPII will include the use of daylight sensors in a combined lighting design to reduce lighting loads, Onsite electricity generation of up to 54MWh annually through solar PV and energy conservation through the use of inverters and battery bank. Future constructions will feature HVAC systems with specific fan power of 2 or less.