High and Low Temperature Conditions (HTC, LTC): definition and testing

HTC is the acronym for High Temperature Conditions and LTC is the acronym for Low Temperature Conditions. HTC is geared to testing panel performance at higher temperature levels, while LTC aims at testing solar panels at low temperatures.

High Temperature Conditions (HTC)

What are the specifications of HTC?

High Temperature Conditions specify testing at irradiance of 1000W/ m², 75°C module temperature, an air mass AM of 1.5 and zero wind speed. It is an extreme-conditions testing standard applied to measure a solar PV module's performance under high temperature conditions which do usually not occur in standard operating situations.

Purpose of High Temperature Conditions testing

Usually, HTC is a very specific testing standard that is used by manufacturers, testing labs and certification bodies to proof a solar panel's resistance against high temperatures, e.g. in desert regions.. It is not a standard test conducted during mass production of solar panels though. LTC is geared to testing panel performance at low temperature levels.

Low Temperature Conditions (LTC)

What are the specifications of LTC?

In contrast to High Temperature Conditions (HTC) testing, the low temperature conditions (LTC) test the performance of solar panels under low irradiance and temperature levels. The solar panel testing parameters are defined as follows: irradiance of 500W/ m², 15°C module temperature, zero wind speed and air mass (AM) of 1.5.

Purpose of High Temperature Conditions testing

Unlike HTC testing, LTC testing parameters are much more likely common in the real world and a good method to measure how a solar PV module performs under low temperature conditions. However, like all other non-mass production major testing conditions such as HTC and LIC, LTC is usually applied during internal and lab tests. During mass production quality testing, manufacturers will still mostly recourse to use Standard Testing Conditions (STC) or (less) Normal Operating Cell Temperature (NOCT)