Senseca PYRAsense03 class C pyranometer with MODBUS-RTU output

Shown below is a Senseca PYRAsense03 class C pyranometer with MODBUS-RTU output:

Top view
Botton view

The new PYRAsense series pyranometers are equipped with diagnostic sensors of internal temperature, pressure, and humidity. The meters are with compact size and easy to mount.

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Outdoor WBGT monitoring station with large water tank and cloud service

Related instruments Thermal comfort & microclimate, Wireless & web data loggers

Shown below is an HD35EDWWBGT outdoor WBGT monitoring station with a large water tank and cloud service.

Data logger and WBGT probes
Base unit with 4G connectivity

The features include:

  • Meets MOM workplace WBGT monitoring requirements
  • Safe for outdoor installations, with solar radiation shield for the temperature probe
  • Large water tank (500 cc), with expected autonomy longer than 1 month in Singapore
  • Data logger is battery power, with 2-year typical life
  • Base unit is with 4G connectivity and supporting cloud reading (note: local 4G subscription required, 230 VAC power supply required, base unit cannot be exposed to rain)

Shown below are the software and cloud portal screenshots:

Shown below is a photo taken from a site:

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Wireless data logger for CO2 and indoor environment measurement

Related instruments Air quality sensors, Wireless & web data loggers

Shown below is a wireless data logger from Senseca for temperature, humidity, pressure, CO2 and VOC index measurement:

Shown below is the screenshot from the data logger software. An HD35APD base unit is used by this customer.

The absolute humidity and wet bulb temperature are calculated from the temperature and relative humidity.

This instrument is great for long-term indoor thermal environment and air quality monitoring. The instrument is powered by USB, and it is possible to be powered by standard phone chargers or power banks.

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Thermal conductivity of 90° rotated mineral wool material

Related services Thermal conductivity

We noticed that some customers provided us with samples with 90° rotated mineral wool insulation material. Shown below is an example. The mineral wool material was rotated by 90°. The test result is significantly higher than the typical thermal conductivity of mineral wool materials. The reasons are explained in this post.

As shown in the sketch below. the mineral wool fibers are aligned in a layered structure.

  • In the normal installation, the heat flow direction is perpendicular to the layered structure. The thermal resistance is greater and the thermal conductivity is lower.
  • In the 90° rotated installation, the heat flow direction is parallel to the layered structure. The thermal resistance is smaller and the thermal conductivity is greater.

A comparison is presented in this page. In this study, the thermal conductivity is 39% higher when the mineral wool material is 90° rotated.

Handheld instrument for VOC index and CO2 measurement

Related instruments Air quality sensors

Shown below is a handheld instrument for CO2 and VOC index measurement, in addition to temperature, humidity, barometric pressure, and air speed measurement.

The meter is HD32.3TC thermal comfort data logger for microclimate index and indoor air quality (IAQ) measurement. There are two probes in the system:

  • Left: HP3217BV4 probe for CO2, VOC index, temperature, relative humidity, and barometric pressure measurement
  • Middle: AP3203.2 probe for omnidirectional air speed measurement

The HD32.3TC can be used for other applications, as described in other posts:

Diffuse daylight reflectance of glasses

Related services Glass optical & thermal properties, Daylight reflectance

As discussed in the glass daylight reflectance page, the diffuse daylight reflectance of a glass is negligible, with the following two relationships:

Diffuse daylight reflectance = 0
Total daylight reflectance = Specular daylight reflectance

In the test report, we will report the glass daylight reflectance only. Below is an example:

There is only 1 result, without the separate total/diffuse/specular reflectance components.

If the result above is expressed in the conventional total/diffuse/specular daylight reflectance format, it would be:

  • Total daylight reflectance = 0.088 (8.8%)
  • Diffuse daylight reflectance = 0.000 (0.0%)
  • Specular daylight reflectance = 0.088 (8.8%)

The diffuse daylight reflectance is negligible, but not exactly 0. It is related to the haze level of the glass. The haze level of typical glasses is less than 0.5%. The diffuse daylight reflectance can be calculated as 0.088 × 0.005 = 0.00044 (0.044%) ≈ 0.000 (0.0%)

In practice, the instrument is not able to accurately measure (or resolve) the diffuse daylight reflectance of a glass. The test method of measuring glass diffuse reflectance is also not defined in the standards.

Therefore, there is only 1 result in the test report, without 3 separate components. The diffuse daylight reflectance of a glass can be estimated theoretically, but cannot the determined by an instrument.

LoRaWAN data logging system for micro-climate monitoring

Related instruments Temperature & humidity, Wireless & web data loggers

Shown in the photo below is a LoRaWAN data logging system for micro-climate monitoring (soil temperature, air temperature & humidity), deployed in a public garden in Singapore:

The following instruments were used:

There are two LoRaWAN data loggers in the system:

  • LR35W1NTC temperature & humidity LoRaWAN data logger: this data logger supports 1 combined temperature & humidity probe
  • LR35WH general purpose data logger: this data logger supports 4 general input channels. In this installation, 4 PT100 temperature probes were connected.

The battery life of both loggers is longer than 2 years.

A few outdoor-type LoRaWAN gateways with 4G connectivity were deployed to provide network access. The signal coverage is around 1 km in an environment without tall buildings (with trees and other structures). The signal strength is reliable, based on the first few weeks of operation.

The data are automatically uploaded to the Delta OHM cloud. The end users can review the results online in real-time. The cloud service is free of charge.

OTM supplied all instruments and provided installation and maintenance services for this project.