Overview.
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Project No.
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021 C 1
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Industry or Sector
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Commercial Office Building
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Energy Use
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Heating
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Date Added
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January 2006
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Abstract
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The use of high efficiency boilers and dedicated domestic water heaters instead of a calorifier results in gas savings of 50% for this Melbourne office building.
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Situation
The two heating water “boilers” in this 1960s office building needed replacing because of excessive maintenance costs and falling reliability. The client had received quotes for boiler replacement, the lowest quote was $68,000. The boilers supplied hot water for building heating, and domestic hot water via a calorifier.
Genesis Now recommended evaluating a range of energy saving opportunities, including high efficiency condensing boilers and a dedicated domestic water heater.
Solution
Genesis Now investigated water heaters on the Australian market, but could not find any which achieved the energy efficiency of some of the condensing water heaters available in Europe.
However, working with potential suppliers, we were able to arrange for the importation and installation two high efficiency boilers.
We also redesigned the hot water system, to include a dedicated domestic water heater and to dispense with the calorifier. This enabled:
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the heating system to be switched off in mild and warm weather, and
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the heating water temperature to be lowered in all but the coldest weather, thus reducing heat losses from the hot water reticulation system, and improving heater energy conversion efficiency.
Our calculations showed that this solution would have a lower total cost of ownership than the original concept.
The Client accepted this solution, despite the higher initial cost of $97,500 ( $29,500 higher than the cost of replacing “like with like”).
Results
The boiler replacement was carried out during the week of 1 May to 5 May, 2005.
Average daily gas consumption before and after heating system replacement:
- May to Nov 2004 22.2 GJ/day
- May to Nov 2005 11.2 GJ/day (50% saving)
Investment Performance
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Investment (additional)
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$ 29,500
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Elec savings
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TBA
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kWh/year
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TBA
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$ / year
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Gas savings ($5 / GJ)
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$20,100
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/year
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Investment return
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14%
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p.a.
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Maintenance Savings
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$ 10,000
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Total Savings
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$ 13,361
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Investment return (marginal cost)
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68%
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p.a.
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Investment return (project cost)
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21%
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p.a.
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Notes: Electricity savings accrue from switching off the heating water pump and boiler ancillaries, and from reduced cooling to combat heat leaking into the building.
Even though this project was initiated by a maintenance requirement, the total project is financially justified by the energy savings alone.
Despite the gas savings of 50% from this action, Genesis Now and the Client are working together to achieve further gas savings in this building, and are achieving additional large savings; these will be documented in a further case study when more gas consumption data is available.
We will be happy to discuss the opportunities to reduce gas consumption in your building.
For other success stories, please see our Case Study Home Page
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