 Client Profile Units under management provide affordable; safe and well maintained value for money accommodation in an environment where tenants can feel proud of their homes. This is achieved through maintaining good relationships and communication with the tenant base, enforcing building rules, preventing overcrowding and noise pollution, and through effective building maintenance. Business Problem Statement The building is located in Johannesburg central. It was historically a commercial building which is now being renovated to accommodate upmarket residential apartments.
The renovation had to include the maximum energy savings possible, consistent with acceptable aesthetics. Technical Situation Building: | Central Jhb | Storeys: | 8 | Apartments: | 133 | Persons: | 399 |
Analysis of Energy Requirements 1. Water Heating No of Persons | 399 | | Hot Water Per Person Per Day | 60 | litres | Hot Water Temperature | 60 | deg C | Avg Inlet Temperature Winter | 5 | deg C | Avg Inlet Temperature Summer | 20 | deg C | Boiler Efficiency | 0.8 | | kCal to kWh Conversion | 1.16E-003 | | Operational Hours per Day | 15 | |
| Winter | Summer | | Boiler | Heat Pump | Boiler | Heat Pump | Litres Demand/Day | 23940 | | 23940 | | kCal Demand/Day | 1316700 | | 957600 | | kWh per day required | 1225 | 552 | 890 | 414 | kW Rating | 81.67 | 36.8 | 59.33 | 27.6 | | | | | | Avg kWh saved daily | 574.5 | | | | Annual kWh saved | 209836.13 | | | |
2. Lighting Essentially, the lighting solution consists of energy – efficient CFL lamps and induction lamps as well as corridor sensors. The installation costs and annual savings are summarised below: Description | Total Cost | Annual Savings – kWh compared to Incandescent etc | Rand Savings Year 1 | Floor 2 | R 224 074.60 | 50 320.36 | R 31 701.83 | Floor 3 | R 224 136.10 | 50 066.32 | R 31 541.78 | Floor 4 | R 223 459.10 | 67 455.22 | R 42 496.79 | Floor 5 | R 217 630.60 | 49 812.28 | R 31 381.74 | Floor 6 | R 218 178.60 | 49 812.28 | R 31 381.74 | Floor 7 | R 186 830.30 | 39 577.68 | R 24 933.94 | Floor 8 | R 155 323.80 | 33 419.4 | R 21 054.22 | Floor 9 | R 151 011.40 | 32 911.32 | R 20 734.13 | Total | R 1 621 164.50 | 373 374.86 | R 235 226.16 |
Solution Heating Gas, Oil, Coal and other forms of direct heating all have comparable costs to direct heating by electricity – the alternative that we are comparing against. Solar heating was not considered because it is not feasible for high-rise apartments and in urban areas where there is insufficient area to provide adequate heat collection. Heat pumps work by moving heat, in this case from hot molecules in the atmosphere to cold molecules inside the hot water supply using the same principles as a refrigerator. Moving heat is very much ore efficient than generating it in the first place and savings of 50 to 60% are routinely achieved compared to direct heating by electricity. Lighting Compact fluorescent lamps remain one of the most energy efficient and cost-effective forms of residential lighting. The CFL downlights provide a considerable saving compared to halogen (50W) whilst maintaining a low level of glare. The Induction fittings used in the public areas are reasonably energy efficient and will discourage theft. The only upcoming alternative to CFL technology is LED, but at present is not acceptable in terms of light quality or cost. Sensors Passive infra-red sensors have been included in the overall solution in public areas where they can save money by only providing lighting when needed. Assessed Benefits of the Proposed Solution Cash Flow - Heating Boiler Cost | R 376 200 | Heat Pump Cost | R 565 200 | kWh Saved Annually | 209836 | R/kWh | 0.63 | Opportunity Cost | R 189 000 | Discount Rate | 0.12 | Escalation rate | 0.15 |
Year | Yield – Loss of Opportuity | Annual Elec Saving- Rands | Cash Flow | Cumulative | 1 | R 211 680 | R 132196.68 | R -79 483.32 | R -79 483.32 | 2 | R 25 401.6 | R 152026.18 | R 126 624.58 | R 47 141.26 | 3 | R 28 449.79 | R 174830.11 | R 146 380.32 | R 273 004.9 | 4 | R 31 863.77 | R 201 054.63 | R 169 190.86 | R 315 571.18 | 5 | R 35 687.42 | R 231 212.82 | R 195 525.4 | R 364 716.26 |
Cash Flow - Lighting The small additional cost of providing CFL lamps compared to incandescent is ignored in the analysis, since the bulk of the cost is that of providing wiring and fittings. kWh Saved Annually | 373374.86 | R/kWh | 0.63 | Escalation rate | 0.15 |
Year | Annual Elec Saving- Rands | 1 | R 235,226.16 | 2 | R 270,510.09 | 3 | R 311,086.60 | 4 | R 357,749.59 | 5 | R 411,412.03 | Total | R 1,585,984.46 |
Total Savings – 5 Year = R 364 716.26+R 1,585,984.46 = R 1 950 700.72 Intangible Benefits Reduction of Carbon Dioxide ( 743384 kg), Sulphur Dioxide (5866 kg) and Total Savings – 5 Year = other pollutants. Products and Services used in the solution | 
| 
| 
| Induction Lighting - Consistent Light Output
- Non Interchangeable
| Deron Heat Pumps | B.E.G Luxomat Detectors | | 
| 
| 
| | LS Flush Populated DB | LS Moulded Circuit Breakers | Lear Switches and Sockets |
|
