 Client Profile
The client is a property owner who places emphasis on social development and urban regeneration in Johannesburg. The owner has developed more than 3000 residential units providing homes to more than 9000 people in the low to middle income communities. The client operates as a private sector, non-profit social housing institution. Business Problem Statement The building is located in Johannesburg central.
It was historically a commercial building which is now being renovated to accommodate middle income residential apartments. The renovation had to include the maximum energy savings possible, consistent with acceptable aesthetics. Technical Situation Building: | Stuttafords | Storeys: | 12 | Apartments: | 107 | Persons: | 270 |
Analysis of Energy Requirements Water Heating No of Persons | 270 | | Hot Water Per Person Per Day | 70 | litres | Hot Water Temperature | 60 | deg C | Avg Inlet Temperature Winter | 8 | 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 | 18900 | | 18900 | | kCal Demand/Day | 982800 | | 756000 | | kWh per day required | 914 | 540 | 703 | 360 | kW Rating | 60.93 | 36 | 46.87 | 24 | | | | | | Avg kWh saved daily | 358.5 | | | | Annual kWh saved | 130942.13 | | | |
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 In this case, the lighting was considered to be in an adequate condition and incandescent lamps were replaced with CFL on an ad-hoc basis Assessed Benefits of the Proposed Solution Cash Flow - Heating Boiler Cost | R 350 000 | Heat Pump Cost | R 551 651 | kWh Saved Annually | 130 942 | R/kWh | 0.63 | Opportunity Cost | R 201 651 | Discount Rate | 0.12 | Escalation rate | 0.15 |
Year | Yield – Loss of Opportunity | Annual Elec Saving- Rands | Cash Flow | Cumulative | 1 | R 225,849.12 | R 82,493.46 | R-143,355.66 | R-143,355.66 | 2 | R 27,101.89 | R 94,867.48 | R 67,765.58 | R-75,590.08 | 3 | R 30,354.12 | R 109,097.60 | R 78,743.48 | R 146,509.06 | 4 | R 33,996.62 | R 125,462.24 | R 91,465.62 | R 170,209.10 | 5 | R 38,076.21 | R 144,281.58 | R 106,205.37 | R 197,670.99 |
Intangible Benefits Reduction of Carbon Dioxide ( 150583 kg), Sulphur Dioxide and other pollutants. Picture of final installation
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