| RSS Web Feed for Renewable Energy UK |  | REUK Shop | Directory | Bookmark Site | About Us  

Effect of Temperature on Solar Panels



Effect Of Temperature On Solar Panels

Experiment to show the effect of temperature on PV solar panel power output

solar | education
Printer Friendly Version Print Article     

All PV Solar Panels are affected by heat. The hotter the solar panel, the lower the power output - but how significant is the effect. We decided to test one of our small 6V 250mA Solar Panels to find out.

Solar Panel next to halogen lamp with temperature probe.

Reproducing the kind of temperatures solar panels experience in hot climates is not easy on a cloudy May day in the UK, so a 150 Watt halogen office lamp was used at a distance of 55mm from the solar panel as a sun substitute (see image above). This guaranteed a constant level of light would be incident upon the solar panel ensuring the quality of the results collected.

Measuring Voltage and Current Under Load

To measure the voltage and current under load, a power resistor was used across the positive and negative outputs of the solar panel. Previous experiments had shown us that the peak power output of these panels is obtained with a load resistance of around 56 Ohms.

56 Ohm Power Resistor to test Solar Panel Under Load

Not having a 56 Ohm power resistor, a 33, 18, and 4.7 Ohm 5 Watt power resistor were connected in series to provide a measured resistance of exactly 55.8 Ohms (see above). The maximum power output of these panels under the halogen light was previously measured at around 750mW, so our 5W power resistors barely got warm.

Measuring Temperature Effect on Solar Panel

Taking voltage, current, and temperature readings manually at one second intervals would be impossible. We were expecting the temperature of the solar panel to increase very rapidly and we wanted the change in power output to be accuarately tracked. Therefore we used the Power Analyzer PRO from Medusa Products.

Power Analyzer PRO measuring voltage, current, and temperature of solar panel under load

This device (pictured above) will measure the voltage and current flowing through the load to 0.005V and 0.01A accuracy, and also temperature to 0.1 degree Celcius accuracy with its probe. Readings are taken of all three values approximately four times every second. By connecting the Power Analyzer to a PC via the included USB cable, the results can be displayed and graphed in real time as well as being stored for later analysis.

Real time data streaming from the Power Analyzer PRO to the PC via USB cable

Solar panels are very dark and so absorb a lot of light (and heat). Therefore the shiny silver coloured temperature probe was wrapped in a single layer of black insulation tape to increase its heat absorption. The temperature of the probe will not exactly match that across the whole surface of the solar panel, however it should be close enough for the purposes of this experiment.

Running The Experiment

Everything was set up and the Power Analyzer initialised with the lamp turned off. When the lamp was turned on it took almost one minute to come to full brightness. Over the next 40 minutes the temperature measured by the probe (and therefore the solar panel) rose to a peak of 75 degrees Celcius. This is similar to the sorts of temperatures the solar panels at the Dubai Energy Tower will reach when that project is completed.

Experiment Results - How Does Temperature Affect Solar Panel Power Output


Graph to show the relationship between temperature and power output of a PV solar panel

The graph above shows the relationship between temperature in degrees Celcius (horizontal axis) and the solar panel power output measured in milliwatts (vertical axis). Because of the way the halogen lamp took one minute to reach full brightness the results from 25-30 degrees Celcius should be ignored.

Between 30 and 42 degrees there was only a small drop in power output from a peak of 749 mW down to 730 mW. After that there was a consistent drop in power output of around 8.3mW (1.1% of peak output) per degree rise in temperature. Voltage under load went from a peak of 6.21V at 0.12 Amps down to just below 5V at 0.09 Amps.

The total power loss due to the increase in temperature was from around 750 mW down to just 458 mW - a fall of almost 40%! Had the solar panel been pre-cooled in the fridge before the experiment was started the peak power output would certainly have been even higher.
Article Last Modified: 16:00, 17th May 2007

Comment on this Article

If you have any comments on this article, please email them to neil@reuk.co.uk.


Recommended Related Articles

People who read this article also enjoyed the following articles:

Measuring the Power of A Solar Panel
Find out how to measure the power output of a PV solar panel
Article Last Modified: 16:22, 17th May 2007
solar | education

Wind and Solar Powered Dubai Skyscraper
Skyscraper to be built in Dubai will generate 100% of its energy needs with wind and solar power
Article Last Modified: 11:40, 22nd May 2007
news | energy efficiency | general

EEStor Battery Ultracapacitor
Find out about a new battery for electric vehicles - 10 times the power of lead acid
Article Last Modified: 08:54, 2nd Feb 2007
storage | news | transport

Calculation of Wind Power
Calculate the power of the wind hitting your wind turbine generator
Article Last Modified: 15:06, 18th Apr 2008
wind | education

Using The LM317T To Regulate Voltage
Use an LM317T to regulate voltage in renewable energy projects
Article Last Modified: 15:04, 7th Mar 2008
electric circuit | electronics

LM317 Voltage Calculator
A handy online output voltage calculator for the LM317, LM338, and other linear voltage regulators
Article Last Modified: 12:47, 12th Mar 2008
electric circuit | electronics | general

Zener Diode Voltage Regulator
Make a simple zener diode voltage regulator
Article Last Modified: 17:31, 7th Mar 2008
electric circuit | education

Power Inverters
Find out about the uses of power inverters in renewable energy generation
Article Last Modified: 16:41, 21st Jul 2008
storage | general | electronics

Storing Wind Power with Compressed Air
Find out how wind power can be stored and sold at times of peak demand
Article Last Modified: 17:17, 11th Apr 2009
wind | storage | news

How to Fit a Small Solar Panel
Find out how to securely attach small solar panels to roofs and other surfaces
Article Last Modified: 11:04, 9th Jan 2009
solar | general

© 2006-2009 REUK - All Rights Reserved
Page Last Updated on 10th July 2009 at 09:47:17am

Latest
Articles


OWL Micro
OWL Micro (CM130) - a leaner and cheaper version of the Owl wireless energy monitor now available
shopping
09:44, 10th Jul 2009

OWL CM119 Wireless Energy Monitor
Find out more about the new OWL CM119 wireless electricity monitor
shopping
09:44, 10th Jul 2009

Freeloader Pro
Introduction to the new Freeloader Pro - the ultimate professional solar charger
solar
16:56, 9th Jul 2009

Solar Roof Tiles
Find out about solar cells built into roof tiles / shingles
solar
12:03, 29th Jun 2009

Automatic Hen House Door Closer Opener
Find out how to put together a DIY automatic hen house door opener and closer
electric circuit
11:47, 27th Jun 2009

Freeloader Solar Charger
Find out more about the Freeloader solar charger for mobile phones, iPods, PDAs, and GPS
solar
12:01, 25th Jun 2009

SolarMate Solar Shed Light Review
A review of the SolarMate 0.5 remote control utility light
solar
10:35, 25th Jun 2009

Immersion Heaters to help Renewable Energy
Find out how the electric immersion heater could enable almost full renewable electricity supply in the UK
general
14:34, 18th Jun 2009



REUK Shop

Popular Items


12 VOLT 5 WATT SOLAR PANEL
Waterproof 12 Volt 5 Watt Solar Panel with aluminium frame - 290mm x 205mm x 17mm with fitted 5m leads
£33.99 each.
Solar Power



300 WATT POWER INVERTER
Convert 12V DC battery power into 230 AC to power portable televisions, computers, video recorders etc. 300 Watt power rating - peak power 600 Watts
£29.99 each.
Renewable Energy System Parts



SOLAR PUMP CONTROLLER WITH RELAY
Solar water heating system microprocessor controlled circuit with fitted 10A relay
£25.99 each.
Complete Circuits



CONVERTED PROGRAMMABLE DIGITAL TIMER RELAY
Mains powered programmable timer converted to low voltage with relay board
£21.99 each.
Renewable Energy System Parts



12 VOLT REGULATOR
Supply a fixed 12.0 Volt DC to your devices (up to 1 Amp output)
£4.99 each.
Complete Circuits



MR16 CERAMIC BULB HOLDER
Bulb holder for 12 Volt LED spotlight bulbs
£1.39 each.
Energy Efficient Lighting