SCIENTIFIC AND TECHNICAL AEROSPACE REPORTS

A Biweekly Publication of the National Aeronautics and Space Administration
VOLUME 44, ISSUE 8 - April 21, 2006

44 ENERGY PRODUCTION AND CONVERSION
Includes specific energy conversion systems, e.g., fuel cells; and solar, geothermal, windpower, and waterwave conversion systems; energy storage; and traditional power generators.

For technologies related to nuclear energy production see 73 Nuclear Physics.

For related information see also 07 Aircraft Propulsion and Power; 20 Spacecraft Propulsion and Power; and 28 Propellants and Fuels.

20060010318 Geological Survey, Vancouver, WA, USA, Washington Univ., Seattle, WA, USA

Solar Electric Power for Instruments at Remote Sites

McChesney, P. J.; January 2000; 76 pp.; In English Report No.(s): PB2006-105362; USGS/OFR-00-128; No Copyright; Avail.: CASI: A05, Hardcopy

Small photovoltaic (PV) systems are the preferred method to power instruments operating at permanent locations away from the electric power grid. These systems, unlike backup power systems or PV power systems for homes, are lightly loaded. There is a shallow battery discharge each night. At high latitudes or where seasonal weather variations limit sunlight, deep battery discharge may occur. The low-power PV power system consists of a solar panel or small array of panels, lead-acid batteries, and a charge controller. Solar panels are rated from ten to several hundred watts. Battery storage capacity runs from tens to hundreds of ampere hours. Charge controllers vary from simple diodes to microprocessor-based devices. The output from these systems is usually 12 volts DC. The load current relative to the system storage capacity is small and these PV systems are able to operate from weeks to months without sunlight. Even though the small PV power system is simple, the job of supplying power at a remote site can be very demanding. The equipment is often exposed to harsh conditions. The site may be inaccessible part of the year or difficult and expensive to reach at any time. Yet the system must provide uninterrupted power with minimum maintenance at low cost. This requires good design. Local conditions complicate the design process. Weather and obstructions at the instrument site cause variations in sunlight making it difficult to balance loads, storage and power input. Successful small PV systems often require modifications by a knowledgeable fieldworker to adapt to conditions at the site. NTIS

Photovoltaic Effect; Remote Control; Solar Energy; Solar Instruments

Source: NASA