Joint Development of 'Hybrid Cooling Workwear' (Peltier Device × Fan-Attached Wear) for Construction Sites in Extreme Heat!

Figure 1: Hybrid Cooling Workwear - Wearing Photo

Showa Shokai Co., Ltd. (Headquarters: Nagoya City, Aichi Prefecture, Representative Director: Shuichi Sano) and Todate Construction Co., Ltd. (Headquarters: Chiyoda-ku, Tokyo, President: Kiyosuke Ohtani) have jointly developed a new type of heat stroke prevention wear, 'BIG PLT FAN VEST,' combining 'Peltier Devices' and 'Fan-Attached Wear' to address the increasingly severe summer heat in recent years.

This device combines Peltier devices, which can reduce the surface temperature of the cooling part by a maximum of approximately 22°C under external temperature conditions, even in high-temperature environments exceeding 35°C or humid environments, with conventional fan-attached wear. This ensures reliable cooling even in extreme heat environments where conventional fan-attached wear could not fully respond, thereby strengthening on-site heat stroke prevention measures.

*Note 1: A device using semiconductor thermoelectric elements, which absorb heat on one side of the element and emit heat on the other when direct current is passed through them, as a cooling unit.

Background of Development: Limitations of Conventional Fan-Attached Wear and Mandatory Heat Stroke Prevention Measures

In recent years, the working environment in outdoor and indoor spaces without air conditioning has become harsher due to record-breaking summer heat. Furthermore, the revision of the Labor Safety and Health Regulations has mandated the 'Strengthening of Heat Stroke Prevention Measures in the Workplace' from June 1, 2025, requiring employers to implement more extensive measures than before.

However, conventional fan-attached wear, which has been the mainstream of on-site heat countermeasures, has the challenge of taking in hot air in extreme heat environments where the outside temperature exceeds 35°C, making it difficult to achieve sufficient cooling effects.

To solve this issue, the company first conducted indoor testing with standalone Peltier devices and performed basic verification of cooling performance. (News Release on March 27, 2024: 'Development of a Backpack-Type Large Cooling Device to Suppress Body Temperature Rise in Extreme Heat Environments')

Based on these results, the company prototyped cooling workwear combining Peltier devices and fan-attached wear, conducted on-site verification at multiple sites, and developed the 'Hybrid Cooling Workwear.'

Three Features of 'Hybrid Cooling Workwear'

The hybrid cooling workwear optimally integrates three elements: 'Peltier Devices,' 'Air Conditioning Fans,' and 'Specialized Fabrics.'

Figure 2: Hybrid Cooling Workwear - External View

1. Cooling in High-Temperature Environments Using 'Peltier Devices'

The device is equipped with Peltier devices that cool directly using direct current, confirming that the surface temperature of the cooling part can be reduced by a maximum of approximately 22°C under external temperature conditions. Additionally, by adopting fluctuation control that varies the strength of cooling over time, it prevents the body from getting used to the coldness while enabling continuous operation for more than 4 hours.

Figure 3: Peltier Device - 3D Rendering Image

2. Improved Comfort Through Synergy with High-Power 'Air Conditioning Fans' (15V)

By increasing the battery output to 15V for powerful airflow, the evaporation heat effect*2 is maximized. By integrating the air conditioning fan and Peltier device into a single structure, the issue of heat buildup around the wearing part, which was a challenge with conventional Peltier devices, has been resolved.

*Note 2: The property of absorbing surrounding heat when a liquid evaporates, which cools the body temperature through the evaporation of sweat.

3. Design Fully Compatible with On-Site Safety Equipment

The Peltier device adopts a unique shape that exhausts air from the side, ensuring that the exhaust port is not blocked. This makes it compatible with reflective vests (commonly known as 'tiger vests') and full-harness-type fall arrest equipment. The design is practical and does not interfere with actual on-site operations.

On-Site Verification: Support from Professionals Working in Extreme Heat Environments

Figure 3: Temperature and Cold Sensation Survey Figure 4: Comparison Survey Results with Fan-Attached Wear

In the 2025 fiscal year, the prototype model was verified at actual construction sites. In the survey, approximately 65% of workers responded that it was 'cool and good' or 'a little cool' (Figure 3). Compared to conventional fan-attached wear, more than 70% received equal or higher evaluations, and approximately more than half of them received evaluations of 'cool and good' or 'a little cool' (Figure 4).

Additionally, many comments of expectation were received, such as 'If the battery operation time is extended and compatibility with full-harness-type fall arrest equipment is achieved, I would definitely like to wear it on-site.' Reflecting these opinions, the company has achieved both the extension of battery operation time and compatibility with safety equipment.

Future Developments

Showa Shokai will continue to contribute to the realization of more practical heat stroke prevention solutions by reflecting the voices of those working on-site in product development, leveraging its expertise in proposing safety and security products and heat stroke prevention products over the years.

In various industries, including construction, manufacturing, and logistics, the company will advance its response to heat stroke prevention needs according to work environments and purposes, while also considering separate specifications and OEM development tailored to corporate requests in collaboration with relevant companies.

Showa Shokai will continue to play a role in connecting customers and manufacturers as a company that understands the field, contributing to the reduction of heat stroke disasters and the creation of safe and comfortable workplace environments.

Showa Shokai Co., Ltd.

Showa Shokai Co., Ltd.
Address: 27-27 Meigetsu-cho 2-chome, Showa-ku, Nagoya City, Aichi Prefecture
Representative: Representative Director President Shuichi Sano
Established: February 1961
Business Description: A comprehensive wholesaler specializing in safety and security products for on-site use, infection control, and hygiene products

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