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Client Profile
Landlord of large building in the Inner City of Johannesburg. The Landlord renovated his building which was previously a hotel in which no water meters, and all pipes, and hot and cold ring mains supplying individual flats were concealed in inaccessible blind ducts. Business Problem Statement
With the conversion to individualised rented units it became necessary to measure both hot and cold water consumption for each flat.
 Technical Situation
| Building: | Stuttafords | | Storeys: | 12 | | Apartments: | 324 | | Persons: | 972 |
Analysis of Energy Requirements
1. Water Heating
| No of Persons | 972 | | | Hot Water Per Person Per Day | 50 | litres | | Hot Water Temperature | 60 | deg C | | Avg Inlet Temperature Winter | 5 | deg C | | Temperature Rise Requirement | 55 | deg C | | Energy Requi | 2 673 000 | kCal | | kCal to kWh Conversion | 1.16E-003 | | | Operational Hours per Day | 15 | | | Heat Pump Requirement | 79.7 | kW |
| | Winter | Summer | | | Boiler | Heat Pump | Boiler | Heat Pump | | Litres Demand/Day | 50000 | | 50000 | | | kCal Demand/Day |
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| | | kWh per day required | 3901 | 993.6 | 3601 | 993.6 | | kW Rating |
| 9.2 |
| 9.2 | | | | | | | | Annual Rand Saving | R 506,825.28 | | | | | Two Year Rand Saving (12% Incr) | R1 074,469.59 | | | | | Five Year Rand Saving (12% Incr) | R3 219,783.64 | | | | | Annual kWh saved | 974664 | | | |
 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.
Assessed Benefits of the Proposed Solution
Cash Flow - Heating
| Boiler Cost | R | | Heat Pump Cost | R 796,000.00 | | kWh Saved Annually | 974664 | | R/kWh | 0.63 | | Opportunity Cost | R 189 000 | | Discount Rate | 0.12 | | Escalation rate | 0.15 |
Intangible Benefits
Reduction of Carbon Dioxide ( 743384 kg), Sulphur Dioxide (5866 kg) and other pollutants.
Products and Services used in the solution | Deron Heat Pumps 
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