DENIS VAN ES Energy Research Institute University of Cape Town 2 October 2002 Energy Efficiency National Electricity Regulator 526 Vermeulen Street, Pta

Project objectives Overall: establish a more sustainable energy sector in South Africa through an increased use of renewable energy and greater energy efficiency on the demand side Immediate: specific building energy audit with recommendations for energy reductions in government buildings

Acknowledgements This project is part of “Capacity Building in DME in Energy Efficiency (EE) and Renewable Energy (RE)” The project is funded by DANCED and is being implemented for the DME by COWI A/S

Preparatory comments The building was not seen by the ERI prior to acceptance of the project Drawings and system data were not made available as required The building was very recently refurbished and underwent a change of use Low occupancy HVAC system partially inoperative Installed HVAC capacity ~40% above requirement No maintenance plan or energy saving plan

Comparative consumption data Benchmark data is not in the public domain for buildings in South Africa Reliance on local anecdotal and foreign data kWh/sq.m-yrTypicalGood practice Overall258? Lighting5427 Small power3123 Hot water104

Building construction Solar shading – overhangs Reflective glazing Internal window blinds Courtyard arrangement

Building services HVAC - VAV Single hot water storage vessel Incandescent, T12 fluorescent tubes, halogen, CFL Small power

Energy accounting Tariff 13 of the Tshwane Metropolitan Municipality – 11kV Values differ from billed amounts TMM could not explain their own tariff Essentially standing charge + demand charge + and energy charge Average monthly energy kWh Average monthly demand 457 kVA Average monthly bill R51 292

Energy conservation opportunities Case 1: switch off lights at night Case 2: replace T12 with T8 & incandescent with CFL Case 3: switch off halogen lamps VSD - little scope Hot water – little scope

Comfort audit ConditionsAcceptable Temperature31% Humidity40% Lighting89% Air movement17% Fresh air23%

Key figures kWh/sq.m-yr HVAC161 Lighting110 [27 – 54] Small power 45 [23 – 31] Hot water 15 [4 – 10] OVERALL331 [258]

Recommendations (energy) RecommendationsPotential Savings (R/yr) Estimated implementation cost (R) Simple payback (yrs) 1Reduce lighting hours Replace light types Add light switches Adopt a good maintenance strategy varies 5Install BMS – – Improve HVAC controls

Recommendations (general) Engage a competent HVAC consulting engineer Detail & price HVAC refurbishment Include energy efficiency techniques Draw up & implement a maintenance programme Appoint competent staff member to oversee maintenance and implement EE programme

Future developments Extend project to produce comprehensive EE guide for all buildings Extend project to audit a number of other buildings in several other cities to create benchmarks Raise public awareness of EE Devise & implement EE standards