Dual Black Globe Temperature
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The BARANI Dual Black Globe Temperature Sensor introduces a patented two-globe approach that provides greater versatility than a conventional single-globe instrument. A standard 15 cm black globe is designed around the human body model specified by ISO 7726 and used in WBGT assessment according to ISO 7243. However, the balance between absorbed radiant heat and convective cooling changes with the size of the person, animal, fruit or plant being monitored. A single globe therefore cannot represent every subject equally well.
By combining two simultaneous globe-temperature measurements with a BARANI-developed correlation algorithm, the sensor can determine equivalent Black Globe Temperatures for several representative sizes. These include a 30 cm globe for large farm animals, a 15 cm globe for human WBGT heat-stress assessment, a 5 cm globe for medium-sized fruit and crops, and a 2.5 cm globe for grapes and other small crops. This enables heat-stress and sunburn-risk monitoring to be adapted more closely to the actual size of the subject instead of relying on a single human-centred reference.
The temperature sensors provide ±0.1 °C accuracy from 0 °C to 70 °C and ±0.2 °C across the wider range from -40 °C to 110 °C. Correlation accuracy is specified at ±0.1 °C for the 15 cm, 5 cm and 2.5 cm equivalent globe sizes, and ±0.3 °C for the 30 cm equivalent. Near-normal emittance is 0.957 ±0.004, with emissivity stability better than 1% per year. The thermistors have a 200-second time constant, long-term stability better than 0.5% per year and IP68 protection.
Designed for permanent outdoor installation, the globes are manufactured from a highly thermally conductive, corrosion-resistant aerospace alloy. An industrial-grade, UV-stable flat-black coating preserves stable emissivity and measurement performance under intense sunlight and at temperatures exceeding 100 °C. The construction withstands weather extremes and golf-ball-sized hail, while the robust 3 mm stainless-steel mount offers multiple installation options. Each sensor uses a five-metre, sunlight-resistant, double-insulated TPE cable.
The Dual Black Globe Temperature Sensor is suitable for smart cities, agriculture, livestock management, occupational safety, construction, meteorology,environmental monitoring and professional weather stations. When integrated with the additional atmospheric measurements required for WBGT calculation, it supports more representative heat-stress assessment for humans and animals of different sizes, as well as targeted sunburn-risk monitoring for crops.
