Solar Power

The sun's energy can be converted to electric or thermal energy with photovoltaic (PV) panels, solar thermal flat plate panels, and solar thermal parabolic-trough collectors. Three simple calculators are provided to determine if solar technologies are a feasible source of energy for a given facility.

These calculators were developed to provide a very general estimation of potential energy savings and simple payback. Any final economic decisions should be based upon the use of more extensive analytical tools.

Photovoltaic Tool

Photovoltaic cells convert sunlight directly into electricity and are made of semiconductors such as crystalline silicon or various thin-film materials. Photovoltaics can provide tiny amounts of power for watches, large amounts for the electric grid, and everything in between.

The photovoltaic array tool estimates possible energy savings if PV panels are used to supply the electricity to a facility instead of conventional methods. The tool takes into consideration current energy consumption, installation area, building specifications, collector specifications, and location specific solar data such as daily solar insolation, mean daily sunshine, and mean ambient temperature.

Download the offline version of Photovoltaic Tool

Flat Plate Water Heater Tool

Flat plate collector solar water heating is a proven technology that harnesses solar radiation from the sun to heat water in place of conventional methods. It uses an insulated, weatherproof box containing a dark absorber plate under one or more layers of transparent or translucent covers. A heat transfer fluid is pumped through a closed loop system, which passes through the absorber plate, to absorb heat. A heat exchanger then transfers the heat from the fluid to water in storage tanks. The hot water produced by the panels can then be used to supplement heating needs. This will significantly reduce hot water heater fuel consumption and associated costs while also reducing CO2 emissions.

The flat plate hot water heating tool calculates the cost savings associated with using solar thermal flat plate collectors to heat water instead of a typical combustion fuel source. The tool takes into consideration the area of the roof that panels can be placed on, annual propane consumption, flat plate collector specifications, and location specific data.

Download the offline version of Flat Plate Water Heater Tool

Parabolic Trough Water Heater Tool

Parabolic-trough collector solar water heating uses mirrored surfaces curved in a linearly extended parabolic shape to focus solar radiation from the sun onto dark glass coated absorber tubes running the length of the trough. Because trough mirrors will reflect only direct solar radiation, a 1-axis solar tracking system is used to keep troughs facing the sun. A heat transfer fluid is pumped through a closed loop system where it picks up heat from the absorber tubes and drops off heat in a water storage tank. This hot water can then be used to heat the greenhouses while the boiler is used to supplement the heating needs. This will significantly reduce boiler fuel consumption and associated costs while also reducing CO2 emissions.

The parabolic-trough hot water heating tool conducts a feasibility analysis for the use of concentrated, parabolic-trough solar heating. The tool provides an estimate for the amount of energy saved if concentrated parabolic-trough solar water heaters are used in place of natural gas water heaters. The tool takes into consideration current energy consumption, installation area, collector specifications, and location specific solar data.

Download the offline version of Parabolic Trough Water Heater Tool

Downloadable Version of the Solar Tools

This version of the tool can be downloaded and installed on a local computer to run the tool. System requirements to use the tool include:

  • Microsoft Excel 2003 or newer

Additional Resources