Water Cooler Timers

The following is a simple Energy Conservation Measure identified for a site in Mexico:

Existing Condition: Water Coolers on 24 Hours per Day
There are at least 10 bottled water dispensers, each of which consumes 1.45 kWh per day to heat and cool the water. These units continue to draw some energy during the evenings and weekends when nobody is in the building, consuming up to 5,293 kWh annually and costing 7,430 pesos ($619 U.S.).

Recommendation: Add Timers to Water Coolers
Add a simple programmable timer to each of the water coolers. The should be set to turn on when people are scheduled to first arrive at the building and turn off when the majority of people are scheduled to leave.

Assumptions:
It is assumed that a simple, 7 day, analog timer will be able to reduce annual energy consumption by at least 50%, saving 3,715 pesos ($310 U.S.) annually. It is assumed that these can be purchased for $15 U.S. (180 pesos) each, or $150 U.S. ($1800 pesos) total, and that no cost of labor is needed to install them.

All costs below in Pesos...

Electric Hand Dryers

Conservation Measure from Recent Utiliyt Audit - Electric Hand Dryers

Summary:
$2,000 first cost, $17,200 annual savings, less than 2 month simple payback.

Existing Condition: Paper Towels in Restrooms
There are at least 9 restrooms in the building, all of which have paper towels for hand drying. Historic purchasing records show that 30 units are purchased per week at $15.42 per unit for an annual spend of $23,125.

Recommendation: Electric Hand Dryers
Remove the paper towel dispensers from restrooms and install energy efficient electric hand dryers. A good hand dryer will use 1,500 W or less and require about 12 seconds to dry the user’s hands. The Xlerator is one such option and sells for $400. It is recommended to install electric hand dryers in the two large production area restrooms. Since 90% of the building users are in the production and warehouse areas, these areas will see the greatest savings. Since the payback will be longer in the office area restrooms and the electric hand dryers can be loud, it is not recommended that hand dryers be used in these areas at this time. Most units do not require special wiring and can be installed with in-house labor. Units can be purchased online at sites such as: http://www.restroomdirect.com/high_speed_hand_dryers.aspx

Assumptions:
It is assumed that 2 hand dryers are needed per restroom for each of the two large restrooms. The units are $400 each. It is assumed that labor and mounting costs will be an additional $100 U.S. for each unit or $500 total. The total cost will be $2,000. It is assumed all 1,900 production and warehouse workers will use the restrooms and the hand dryers 3 times per day for 250 days per year. The units will draw 1.5 kW and will run for 12 seconds per use (0.0033 hours) for a total annual electricity consumption of 7,125 kWh. At $0.12 per kWh, this is $855 per year. It is assumed that 75% of the total annual paper towel cost is attributed to the two large restrooms, which represents $18,038 annually.

Notes:
This measure was identified for a factory in Tijuana. All prices were converted from Pesos.

Calculating Energy Savings

On Friday, I presented a brown bag lunch presentation on Calculating Energy Savings to the OFS staff. The presentation started with a look at some spreadsheets I'd created to quickly calculate the savings from two easy energy retrofits... reduced pressure drop air filters and premium efficiency motors. The Excel file had pages started for calculating a number of other types of savings, but wasn't quite ready to share at this time. Next we went over part of the attached Power Point starting with how to calculate lighting fixture requirement using the Lumen Method (the agenda on the second page of the presentation was never changed to represent the actual presentation). We then went over the Fundamental Law of Illumination and how fixture distance affects illuminance. The presentation continued with an explanation of energy models and how they work. We then finished by looking at an eQUEST version 3.62 model for one of the undergraduate houses and quickly reviewing some of the inputs and summary reports. About 6 people attended.

Dunster Kitchen Controls

Our Dining Services group recently worked with National Resources Management to reduce energy consumption in their kitchens. They put in controls to to reduce short cycling of the walk-in cooler and freezer compressors, run the evaporator fans only when needed, and run the defrost cycle based on coil temperature. NRM also installed anti-sweat door heater controls and replaced the small evaporator fans with much more efficient Electronically Commutated Motors (ECM) motors, as is being done in the picture on the right in a cooler at Dunster House, where 2 coolers and 2 freezers were upgraded. The new controls are able to be monitored remotely to track refrigerator and cooler performance and to verify energy savings (the small image on the bottom right shows a screen shot tracking the Dunster House kitchen). The overall project covered 14 walk-in coolers and 8 walk-in freezers in 4 kitchens, cost about $80,000 after utility rebates, is estimated to save over $28,000 annually (simple payback in less than 3 years), and will reduce greenhouse gas emissions by over 62 metric tons of carbon dioxide equivalent per year. Details of the Dunster project are included on the bottom left. The whole project was funded through the Green Campus Loan Fund and the loan will be repaid as the energy savings are realized.