Subway Drive-Thru Restaurant – Case Study

A Subway Drive-Thru Restaurant conducted a full energy audit to consider the savings by installing an energy management system and power factor correction on their sandwich store.

The table below outlines the scenario and savings after the AuziMAX EMS and power factor correction equipment from Edge Electrons was installed.

With annual savings of approximately $3,300 per year, the equipment and installation has a return on investment of 24 months.

Energy Costs per Annum

$35,000

Average Energy Use per day

480 kWh

Network Demand

35 kVA

Power Factor

0.85

Energy Reduction Solution

1. Install AuziMAX EMS (20 channel) with Demand Management
2. Install 10kVAR Power Factor Correction Unit

kVAR Savings

4.1 kVA – The PFC unit is increasing the Power Factor from 0.90 to unity, and saving 4.1 kVA from network demand charges.

Demand Savings

kWh Savings

The AuziMAX EMS is controlling the main restaurant Air Conditioning unit plus the hot water system with a combined kVA saving of 6.8kVA

AuziMAX EMS is providing incremental kWh savings of 0.4MWh / mth in association with demand management. This could be increased by the addition of standby power relay for overnight savings.

Equipment Investment

20Ch AuziMAX EMS incl. load controls – $3900
Edge 10 KVAR PFC – $1300
Installation – $1200
Total $6,400

Total Savings and Expected Return on Investment

Approx. $3,300 annual saving – ROI of 24 months – comprising of network demand reduction of 10.9 kVA (30% of max demand), and Energy Efficiency saving of 4.8MWh per annum.

Future Energy Saving Initiatives

Based on the energy data gathered the following initiatives are to be implemented:
a) Reduction of known standby consumption
b) Reduce 7am peak demand by having staff fill the hot water sink 15mins earlier so water heating does not coincide with bread baking

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