Page 12 - North American Clean Energy May June 2015

solar energy

Solar Data Loggers

Verifying performance & securing rebates

by Stew Thompson

Recorded energy data presented in bar graph form using data logger software. Fluctuating current and voltage levels captured by regular sampling throughout a 10-day period.

Lowering energy bills with a green energy one of these rebate programs or to ind savings areas on which quickly allow users to upload all recorded data to a
grant
an existing PV (photovoltaic) installation. hese systems PC for later analysis using the logger software.

Across the country, businesses and schools are qualifying for ultimately become an economical solution by allowing
new federal and state solar energy rebates, grants, and tax businesses to upgrade to solar energy systems, thus in- What’s needed to get started?
credits in order to lower energy costs. To qualify for these creasing energy eiciency, and saving on power costs.
here are a variety of data loggers on the market and
breaks, most inanciers require grant recipients to collect their Solar data loggers record solar irradiation up to a numerous accessories as well. A basic set-up to monitor

own energy performance data and periodically present beneit certain value measured in W/m2 (watts per square solar panel eiciency through logging solar irradiance,
assessment data as a proof of results. With this end in mind, meter), and many models also record the voltage and system current, and voltage should include:
solar data loggers are an ideal way to record a solar system’s current produced by the solar panel. his accurately • a pyranometer to measure solar irradiance;
wattage capacity to allow a comparison to the installer’s quoted assesses the performance of a solar energy installation. • voltage input leads;

output. Using a data logger, energy data is available to verify
Energy upgrades such as solar water heaters can pay • a DC current probe; and
if solar power systems are performing as projected and to for themselves over a few years. Here, data loggers are • data logger software to view, analyze, and print out the
conirm installers’ rates are accurate. With a data logger, it is afordable solutions to maintain funding by proving data.
possible to perform an energy audit to help a facility qualify for
energy savings to government and service providers.

Some loggers come with all the necessary equipment
Record solar irradiance & DC voltage/ included; others, may have an additional cost.
current produced

Many data logger models record the solar irradiation Software shows the whole picture
of PV systems and the current/voltage produced by the By using data logger analysis software, energy data
solar panel. For example, a particular recorder might graphs can be generated as proof, revealing if the prom-
monitor using one or two DC voltage channels from 1V ised savings are really there. his is especially important

to 40Vdc, allowing users to view PV cell output and the when federal or state monies and regulations are in-
voltage and current curves during the day.
volved. For example, contracted service technicians or
Data loggers sample every channel a certain number school board members can use printouts to prove energy
of times per cycle (a cycle being 16ms at 60Hz and 20ms eiciency and HVAC savings.

GreenFasten
TM
at 50Hz). Some data loggers will save and store the Most software applications are fairly straightforward
average voltage (VAvg/TRMS average) and current, if and intuitive. Typically, users can view recorded voltage
applied, for each channel over the period chosen. hese levels, time-stamped data in tabular and graphical form,
loggers can also record the highest (VMax) and lowest export data to a spreadsheet, or print out reports. For

(VMin) cycle values on each of their input channels larger installations, some logger software also features
during the averaging period. To zero in on data, voltage an internal database managing the distribution of
levels are stored with date and time stamps. Viewing multiple units.
these ‘peaks and valleys’ will provide the information

needed to justify the system and give proof to inanciers.
Beneits summary
hese readings can be stored on internal memory, and a Green energy rebate programs are a great way to
non-volatile memory will enable retrieving the data even upgrade to more eicient systems and cut energy
when the logger isn’t powered. Depending on the length costs. A solar data logger records energy data and is

of time needed to record, a unit with a large memory may an afordable way to help qualify for these rebates by
Solar roof mounts for all roof types
be necessary. With a back-up battery, a data logger can
providing proof that the savings are actually achieved.
be left to record unattended. his is ideal for equipment
monitoring applications such as PV installations. Stew hompson is the marketing specialist at CAS Data
www.ecofastensolar.com
Additionally, an external power supply unit (PSU) input Loggers, Inc.
can allow for prolonged logging without batteries. To
quickly retrieve the data, USB ports are a standard feature
CAS Data Loggers | www.dataloggerinc.com

12 nacleanenergy.com
MAY/JUNE 2015