Tracy Dahl Polar Field Services
Partner in CH2M Hill Polar Services
Ventana Multi-Azimuth Array
(E/S/W) solar PV with wind turbine to LiFePO4 battery.
North Slope, Alaska
Developed for the Deegan/Urban project, the primary criteria for this NSF funded power system are portability, quick set-up and medium range power capability. The system powers a sonar unit, computer and peripheral equipment. Primary power input is via the multi-azimuth PV array and an APRS WT14 wind turbine. A 20 amp AC/DC battery charger provides a back-up power option.
The system is moved multiple times per summer season via R44 helicopter, thus requiring minimum weight and fast set-up time. Because of this and the power requirement (80Watts – 100Watts continuous), a lithium battery was selected for the energy storage. The LiFePO4 battery by OES has 3.2kWh of available energy storage, weighs only 70 lbs, and is “air eligible”. The equivalent energy storage in lead acid would weigh around 250 lbs.
The three sided solar PV array takes advantage of the high latitude summer solar cycle, providing up to 20 hours of battery charging per day. The three Genasun MPPT charge controllers are optimized for the Kyocera KD140 PV panels and the lithium battery chemistry, maximizing the daily energy harvest. There is no conventional array frame. Rather, the three panels each have two adjustable aluminum angle legs that minimize weight, size, complexity and set-up time. The three panels bolt together, creating a self-supporting, three dimensional structure. All electrical connections are tool-less, plug and play design. Water resistant electric trolling motor connectors are used for the PV (any panel can plug into any receptacle). The connector for the APRS wind turbine is a mil-spec water resistant design as well.
The APRS WT14 wind turbine is optimized for the low wind speed conditions typical on the North Slope of Alaska. Capable of up to 750 Watts output, the machine was originally designed for Department of Defense applications and features an excellent power to weight ratio and tool-free assembly. To expedite repeated set-ups at different locations, a special high tech rope is used rather than conventional steel cable and turnbuckles. The entire system can be set up in less than one hour by experienced team members.
Set-Up, Operations and Maintenance ManualDeegan/Urban Power System Photo Document
Solar Generation: Three facets, each deploying one Kyocera KD140 (140W) module. Results in up to 20 hours per day of solar battery charging.
Solar Charge Control: Three Genasun MPPT “Solar Boost” charge controllers, optimized for both the KD140 panels and the lithium battery chemistry. The design optimizes energy production and adds a level of redundancy to the system.
Wind Power: APRS World WT14 turbine. Features an excellent power to weight ratio (22lbs/750W), tool-free installation and is an extremely robust little machine. See: http://www.aprsworld.com/wtaprs/WT10/
Wind Charge Control: Morningstar TS45 and resistive dump load. The modified charge controller and dump load were provided by APRS as part of the wind power package.
Energy Storage: One OES (Optimized Energy Storage) 3.2kWh, 24V (nominal) lithium ferrous phosphate (LiFePO4) battery. Features an excellent energy storage capacity at about ¼ the weight of lead acid battery technology. Built in battery management system (BMS). Air eligible. See: http://www.oesoptimizedenergystorage.com/pdf/OES-3-4-24V-and-48V-Brochure-5-8-15.pdf
DC/AC Inverter: Analytic Systems IPS 300, 300W output @ 115VAC, mil-spec, -40C - +50C temperature range, conformal coated PC board, integral GFCI protection *AC power is available inside and outside of the enclosure. An AC extension cord has been included, but is not expected to be used on the Deegan project.
3ea) Plug/Receptacle: Marinco Connect Pro Combo, 2-wire receptacle/plug. This is a DC rated, water resistant electric trolling motor connector.
Balance of System Components:High quality components used throughout, including Polar Wire “Arctic Ultra-Flex” conductors, DC rated circuit breakers, ferrules on most lug connections, heat shrink crimp connectors, etc.
The aluminum truck box used as the power electronics enclosure was purchased through Northern Tool and Equipment. It has been reinforced as necessary with dimensional lumber and plywood. The battery compartment is insulated with a minimum of 1.5” of Styrofoam to maintain a more consistent temperature.