thermal comfort – OTM Solutions Pte Ltd

Indoor air velocity monitoring with HD403TS2 omni-directional hot wire anemometer

chen.fz@otm.sg Instrumentation 30/06/202523/04/2025air velocity, thermal comfort, wireless data logger 0 Comment

Related instruments Airspeed & wind, Wireless & web data loggers

Shown below is an integrated system for indoor air velocity monitoring, ideal for thermal comfort applications:

Wireless data logger with USB dongle base unit

The system consists of the following components:

HD35APD.E USB dongle base unit
- Acts as the communication bridge between the wireless data logger and a computer.
HD35EDWH.E general-purpose wireless data logger
- Supports up to 4 analog input channels. Compatible with typical analog signals such as 4–20 mA, PT100, and thermocouples.
HD403TS2 omni-directional hot wire anemometer
- Measures air velocity in the range of 0 – 5 m/s. Suitable for accurate indoor air flow measurement.

The system was integrated by OTM, for easy deployment by the end users. Shown below is a screenshot of the computer software interface:

Related instruments

HD35EDWH outdoor general-purpose wireless data logger

HD403TS2 hotwire air velocity transmitter (omnidirectional probe, 4–20 mA)

HD35APD USB dongle base unit

Weather station for outdoor thermal comfort monitoring

chen.fz@otm.sg Instrumentation 27/01/202507/02/2025outdoor, thermal comfort, weather station 0 Comment

Below is a weather station integrated by OTM for outdoor thermal comfort monitoring:

The station measures the following five environmental parameters:

Wind speed and direction
Air temperature and humidity
Globe temperature

These measurements are used for outdoor thermal comfort analysis, such as calculating the Universal Thermal Climate Index (UTCI). The data is automatically logged by the instruments and uploaded to a cloud server.

The following key instruments are used:

We also provided installation and maintenance services for this project.

Related instruments

TP875.1.I globe thermometer probe (radiant heat measurement, Ø150 mm)

HD33MT.4 weather station data logger with 4G connectivity

HD53LS 2-axis ultrasonic anemometer

HD9008TRR temperature & humidity transmitter (4–20 mA output, meteorological grade)

Exhibition in WSH Forum on Heat Stress Management 2023

chen.fz@otm.sg Instrumentation 26/05/202328/05/2023exhibition, thermal comfort, WBGT 0 Comment

Related instruments Thermal comfort

OTM exhibited in WSH Forum on Heat Stress Management 2023 (25/05/2023, NUS Shaw Foundation Alumni House Auditorium), with the following two instruments exhibited:

HD32.3TC handheld instrument for WBGT measurement; key features:
- With a large color touchscreen
- Probes are interchangeable for various thermal comfort and micro-environment measurements
- High accuracy
HD35EDWWBGT wall-mounted instrument for WBGT measurement; key features:
- For long-term WBGT monitoring (up to 500 ml water capacity for the natural wet bulb temperature probe)
- Suitable for outdoor installation
- With a wireless data logger and it is possible to configure it with cloud connectivity
- High accuracy

Shown below is a photo of our booth:

We are grateful for the exhibition opportunity and booth setup assistance provided by WSH Council and MOM, and also the exhibition items provided by Delta OHM.

Instrument for outdoor thermal comfort measurement (with solar panel and cloud service)

chen.fz@otm.sg Instrumentation 10/04/202323/04/2023globe thermometer, thermal comfort 0 Comment

Related instruments Temperature & humidity, Air speed & wind, Thermal comfort

Shown below is an instrument integrated by OTM for outdoor thermal comfort measurement:

Below are the key features of the system:

Four quantities are measured: air temperature, relative humidity, airflow speed and globe temperature
Data logger included
With 4G connectivity and cloud service
With solar panel
Suitable for outdoor 24×7 monitoring
The height of the stand is adjustable in the range of 0.9 m to 1.5 m

Shown below is a screenshot of the cloud service portal:

Listed below are the key components in the systems:

Data logger: HD33MT.4 data logger
Air temperature & relative humidity sensor & solar radiation shield: HD9009TRR & HD9007A-1
Globe thermometer: TP876.1.I
Omni-directional hotwire anemometer: HD4V3TS2

Thermal comfort data logger for UTCI measurement

chen.fz@otm.sg Instrumentation 13/02/202319/02/2023thermal comfort 0 Comment

The Universal Thermal Climate Index (UTCI) is a measure of the thermal environment that influences human comfort and health. The HD32.3TC thermal comfort data logger for PMV/PPD/WBGT/turbulence measurement can be configured to measure UTCI, without hardware changes.

Shown below are some photos of HD32.3TC in the UTCI measurement mode.

WBGT measurement with natural wet bulb temperature probe

chen.fz@otm.sg Instrumentation 10/10/202214/10/2022thermal comfort, WBGT 0 Comment

Related instruments Temperature & humidity, Thermal comfort

An earlier post showed WBGT measurement with a combined temperature and humidity probe. With this configuration, the natural wet bulb temperature is calculated.

Shown below is a configuration of the same HD32.3TC instrument with a wet bulb temperature probe. In this case, the wet bulb temperature is directly measured, in compliance to ISO 7243.

HD32.3TC can be configured in various ways for thermal comfort, indoor air quality and microclimate analysis. Please refer to the data sheet of HD32.3TC for more details.

Omni-directional air speed transmitter for thermal comfort applications

chen.fz@otm.sg Instrumentation 14/02/202207/05/2022air speed, thermal comfort 0 Comment

Related instruments Air speed & wind, Thermal comfort

Shown below is an Delta Ohm HD403TS2 omni-directional air speed transmitter for thermal comfort applications. The measurement range is 0-5 m/s and the output type is 4-20 mA (0-10 V option is available).

The probe can be installed with a standard PG9 or PG11 cable gland.

50 mm globe thermometer for thermal comfort applications

chen.fz@otm.sg Instrumentation 10/01/202224/04/2024globe thermometer, PT100, thermal comfort 0 Comment

Related instruments Temperature & humidity, Thermal comfort

Shown above is a 50 mm diameter globe thermometer, with Class A 4-wire PT100 sensor. The model is Delta Ohm TP876.1.I. An alternative model with 150 mm diameter (TP875.1.I) is also available. Refer to the instrument datasheet for more information.

For the working principle of globe thermometers, please refer to this article.

[updated on 24/04/2024]

Shown below is the photo of the 150 mm model (TP875.1.I):

Thermal comfort data logger for PMV/PPD/WBGT/turbulence measurement

chen.fz@otm.sg Instrumentation 10/08/202119/02/2023thermal comfort 0 Comment

Related instruments Temperature & humidity, Air speed & wind, Thermal comfort

Shown below are two sets of Delta Ohm HD32.3TC thermal comfort data loggers, with the following features:

For PMV/PPD/WBGT/turbulence measurement (ISO 7726, 7730 and 7243)
4 quantities measured: air temperature, humidity, speed and globe temperature
Portable
With large touch screen
With built-in Li-ion battery (chargeable via USB)
With voice recording and camera function
With wi-fi connection for FTP upload

Visit our thermal comfort instrument page for more products.

With the 3 probes connected (globe thermometer probe, combined temperature & humidity probe, and air speed probe), it is possible to display either PMV/PPD results or WBGT (both indoor and outdoor) results, as shown below:

The instrument can also be configured to measure UCTI (Universal Thermal Climate Index), with the same probe set.