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eCharge for No Idle HVAC

Volatile fuel prices and increasingly stringent anti-idling regulations are prompting class 8 fleet owners and operators to search out new solutions to power to in-cab HVAC. Through a new strategic partnership, eNow, Inc. and Bergstom, Inc. are marketing solar powered No Idle HVAC systems for class 8 vehicles.
eNow’s proprietary solar battery charging system stores power generated by the sun in an on-board battery system and distributes it to various truck/trailer functions, including the Bergstrom battery-powered NITE HVAC system. The solar powered NITE system generates cooling capacity and helps reduce emissions and comply with anti-idling laws. As demonstrated below, the system also saves money on fuel.
eNow tested 1200 Watt and 600 Watt solar charging systems in two separate NITE HVAC applications to measure cost savings and recharge efficiency and reliability. As described below, the test data show:
• A system use for 23 days over a nearly two-month period resulted in $867 in fuel savings, or
$6,936 annually. Most of this savings is the result of fuel savings from reduced idling to run the HVAC system ($675/$5,400), while additional savings ($192/$1,536) results from reducing the alternator load. This translates into a payback period of approximately 1.3 years using a 30% federal tax credit.
• The system was used an average of 7.33 hours a day during test period, and up to 10 hours a day. Savings increases with the amount of time HVAC is used. If the driver had used all of the solar power generated to run the NITE system more hours, total savings could have been up to $1,600 over the test period or $12,800 annually.
• Under concurrent daytime use of the NITE system with solar production, NITE system batteries were fully recharged by the solar system by 1 PM the next day, even in cloudy/rainy conditions.
Test Design – Arpin Van Lines
eNow worked with Arpin Van Lines to monitor cost savings from a solar powered NITE system. The 600 Watt system was installed on Arpin’s class 8 moving van consisting of a tractor and trailer. The NITE system was operated an average of 7.33 hours per day on 23 days from May through June 2012. The system generated $867 in savings during the test period Chart 1), or $6,936 in annualized savings (Table 1).  Savings increases with the amount of time HVAC is used. If the driver had used all of the solar power generated to run the NITE system more hours during the test period, total savings could have been up to
$1,600 over the test period or $12,800 annually.


Test Design – eNow Demonstration Truck
The eNow demonstration truck is installed with a 1200 watts solar panel system. Power generated by the panels is used to run the several vehicle systems, including safety lights, computer screens and the Bergstom Nite Phoenix HVAC system.   An Onset Hobo data logger is to track the amount of power generated from the solar panels as well as the power consumption of the Nite Phoenix system. This test period spanned two months (7/19/13 through 9/18/13). During that time the truck traveled to various shows and demonstrations. Most of the time the truck was not in use. Since the Nite Phoenix system was not run every day, auxiliary batteries were normally in a fully charged state. Whenever the Nite Phoenix system was used, the batteries were replenished by the solar system. During the test period the Nite Phoenix system consumed 48.6 kWh of energy and the solar charging system replenished 56.6 kWh of energy. During this time energy used for other auxiliary systems (computers, lights, etc.) also was recovered by the solar charging system.
The test was undertaken to measure the ability of the solar charging system to recharge NITE Phoenix system batteries while the system was in use during cloudy/rainy conditions.
The test ran the Nite Phoenix system concurrently with solar production on a partially cloudy day with an afternoon rain shower. Weather conditions lowered solar output and the battery was not fully recharged on the first day. At the end of the 5 ½ hours of operation the deficiency of the battery was a net of 151 amp- hours. However, solar charging made up the deficiency the next day. By 11:00 AM the charge controller went into absorption phase for completing  the charging of the battery. The battery was completely recharged by 1:30 PM (Chart 2). It is noted that the cooling area of the demonstration truck is 970 cubic feet, larger than most cabs, and is uninsulated.


Conclusion
The solar powered NITE HVAC system provides class 8 vehicles with reliable cabin comfort while reducing fuel costs and helping to achieve no idle and emissions reductions regulations. Annualized fuel savings from the solar powered no idle HVAC system amounted to $6,900 during the test period, but could have reached $12,800 under full use of the solar power available to run the HVAC. Battery recharge by the solar system is reliable even under cloudy rainy conditions.