Making a Case for Energy Savings

As with many energy audits, the goal of a recent assessment of a commercial office building on Staten Island, New York, was to investigate and identify cost-effective energy conservation as well as operating and maintenance and make recommendations for their implementation. Using instrumented data collection and system efficiency testing techniques applied during the assessment, Paulus, Sokolow...

08/01/2004


As with many energy audits, the goal of a recent assessment of a commercial office building on Staten Island, New York, was to investigate and identify cost-effective energy conservation as well as operating and maintenance and make recommendations for their implementation.

Using instrumented data collection and system efficiency testing techniques applied during the assessment, Paulus, Sokolowski & Sartor/KeySpan and CEC engineers reviewed and evaluated performance parameters for heating and cooling, building envelope, lighting and ventilation systems in order to recommend an appropriate scope of work. Based on the team's experience with energy conservation retrofits and life-cycle costing, they performed an analysis of the measures most likely to result in a substantial reduction in energy.

The following measures were recommended:

  • Replace one existing boiler and chiller with two new gas-fired chiller heaters.

  • Upgrade lighting in common areas and garage with new fixtures, photocells and occupancy sensors.

  • Upgrade MG-set driven elevators with new VVVF controls.

  • Install variable-frequency drive on chilled and hot-water distribution pump.

These recommended measures should result in a 35.6% reduction in fuel use—from 75,472 therms to 48,617 therms—and a 13.3% reduction in electricity consumption—from 627,590 kWh to 544,110 kWh. Electric demand savings for these measures should come to approximately 15 kW.

Additionally, the auditors evaluated the replacement of the ninth floor packaged air-handling units with new AHUs supplied by the central plant. While this analysis yields significant savings, they are not sufficient to justify the capital to replace the units. However, should poor operations and high maintenance costs on the units prompt changeout in the near future, the team recommended installing air handlers with coils supplied by the central plant.

Finally, the consultants recommended that the client apply for the New York Energy $mart Loan Fund. Through this program, the state buys down 400 basis points off any loan for the implementation of energy-efficient measures.

In the end, the client stands to save more than $17,000 annually, if all recommended conservation measures are implented.

Sample Audit Results for a Commercial Office Building
Staten Island, NY

Measure

Installed Cost

Energy Savings

Demand Savings

Cost Savings

Pay Back

(mmBTU)

(kWh)

(kW)

($)

(Years)

1) Boiler/Chiller Replacement

$613,664

2,685

571

0

$20,825

29.5

2) Common Area/Garage Lighting

$9,119

0

31,916

2

$4,590

2.0

3) CHW/HW Pump VFD Existing Plant

$5,000

0

20,402

0

$1,798

2.8

4) CHW/HW Pump VFD New Plant

$5,500

0

24,483

0

$2,157

2.5

5) Window Replacement Package

$189,541

1,005

0

0

$7,379

25.7

6) Upgrade Elevators wit VVVF and AC drives

$60,000

0

50,993

13

$7,599

7.9





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