Japan's Air Conditioner Makers Take Cooling Outdoors as Summer Heat Intensifies

Daikin and Panasonic Test Relief Beyond Buildings

Daikin Industries and Panasonic are taking cooling technology into Japan's parks, public spaces and outdoor events as increasingly intense summer heat makes daily life outside more uncomfortable and dangerous. Their trials range from equipment that blows refrigerated air to misting systems designed to create small areas of relief in otherwise hot surroundings.

Japan's cities experienced some of their highest temperatures in 2023 and 2024, including in Osaka and Tokyo. Heatwaves lasted for weeks, while warm nights offered little relief. The Japan Meteorological Agency repeatedly issued heatstroke warnings, and public health officials reported a surge in illnesses associated with heat.

As of August 9, 2025, manufacturers are testing how cooling systems perform beyond the enclosed rooms for which air conditioning is usually designed. The work involves more than measuring temperature: companies are examining electricity consumption, comfort and whether people welcome the equipment in shared spaces.

Daikin, a global leader in heating, ventilation and air conditioning, has deployed outdoor cooling units in public parks and event spaces. Panasonic has experimented with misting systems and portable cooling stations at festivals and outdoor markets. Their goal is localized relief for people spending time outside, whether they are working, travelling or enjoying public spaces.

The ambition is to create "oases" of cool air, a description used in the outdoor cooling report. Making those small areas comfortable, while controlling energy and water use, is the central engineering challenge.

Why Cooling a Street Is Different From Cooling a Room

Tokyo, Osaka and other densely built cities face the added pressure of urban heat islands. Concrete and asphalt absorb heat and release it into their surroundings, making outdoor spaces hotter. People encounter that stored heat while walking, waiting for transport, shopping or working outside.

Conventional air conditioning provides relief inside homes and offices, but people cannot always remain indoors. Government and industry are therefore looking for ways to make outdoor environments more comfortable while limiting the resources needed to cool them.

An enclosed room holds cooled air within walls and windows. A park, plaza or street receives continuing heat from the sun, and cooled air can move away. Equipment placed outside must therefore concentrate its effect where people actually stand or sit.

Japanese trials are exploring several approaches: fine water mist, portable air conditioners, wearable cooling devices and more advanced systems for outdoor or partly enclosed settings. Each operates at a different scale. A neck fan serves one person, while a misting installation can serve a shaded walkway or seating area.

The field tests are intended to establish how much comfort these technologies provide, how much energy they consume and how people respond to them. Their wider purpose is to help cities adapt public spaces to increasingly severe summer heat.

How Water Mist Takes Heat From the Air

Misting systems spray fine droplets of water overhead. As those droplets evaporate, they absorb heat from the surrounding air. This process, called evaporative cooling, can lower the temperature without using refrigerants, the substances that carry heat through a conventional air conditioner.

Studies in Mediterranean cities and Japanese urban spaces have found local temperature reductions of up to 8°C, with minimal increases in humidity. The strongest effect occurs within about half a meter of the spray, making placement especially important.

Shaded walkways, bus stops and outdoor seating areas are among the locations suited to this concentrated cooling. A system positioned close to where people gather can provide relief without attempting to cool an entire street.

Humidity affects the result. Evaporation works best in dry or moderately humid air; when the air is already very humid, water evaporates less readily and the cooling effect weakens. Japan's humid summers therefore make local conditions a central part of any installation decision.

Research on mist cooling published through ScienceDirect identifies spray height and placement as important to obtaining the greatest cooling effect while minimizing water use. Field studies in Japan and Europe have also found improvements in outdoor comfort and reductions in heat stress.

What Field Tests Show About Comfort

Surveys in Japanese cities found that people using misted spaces reported less heat stress and greater willingness to spend time outdoors. Installations performed best in shade with light breezes, with the mist suspended just above head height.

An urban planner involved in a Tokyo field test described how the installation changed use of a plaza during the hottest part of the day:

The misting system made the plaza usable even during the hottest part of the day. People gathered under the mist, and we saw a noticeable drop in heat-related complaints.

Mist can make a previously uncomfortable gathering place more usable. The benefits depend on the surrounding conditions, including shade, airflow, humidity and how close people are to the spray.

Water consumption and maintenance remain concerns, particularly in regions prone to drought. Misting systems need a continuing water supply, and outdoor installations must remain reliable despite weather and repeated public use.

Manufacturers and researchers are using these trials to examine both performance and public acceptance. A system that lowers temperatures must also fit the way a plaza, walkway or event space is used.

Portable Air Conditioners Offer Concentrated Relief

Portable air conditioners use fans and a refrigerant cycle to deliver cooled air. Refrigerant absorbs heat in one part of the system and releases it elsewhere, allowing the equipment to blow cooler air toward the people who need it.

Compact mobile units are being deployed at outdoor events and temporary installations. Refrigerated cooling can provide stronger relief within a small area, although operating in the open is less efficient than cooling an enclosed room.

Small spaces that are partly enclosed are particularly suitable. Cooling stations can also serve outdoor events, construction sites and temporary shelters during heat emergencies. Their value lies in directing relief toward a limited area rather than changing conditions across a large public space.

Japanese manufacturers are working on advanced compressors, variable refrigerant flow technology and smart controls to reduce electricity consumption. These improvements matter because cold air disperses outside, increasing the difficulty of delivering useful cooling with limited power.

Variable refrigerant flow, usually shortened to VRF, adjusts the amount of refrigerant moving through the system to match cooling needs. Comparisons with constant refrigerant flow systems, or CRF, in hot climates have found energy savings of up to 27%, making VRF a promising option for outdoor applications.

Portable units still have a limited reach. Field tests indicate that they are best used for targeted relief in small or partly enclosed settings, while wider outdoor spaces require attention to shade, layout and other cooling measures.

Wearable Devices Bring Cooling Closer to the User

Neck fans and wearable air conditioners are becoming popular among commuters and outdoor workers in Japan and abroad. Instead of cooling a shared space, these devices aim to provide a small personal area of relief while someone walks, travels or works.

Some use fans powered by batteries to move air around the wearer. Others use thermoelectric cooling chips, which use electricity to create a cooling effect. Their appeal is portability: a person can carry the device from place to place.

The New York Times' Wirecutter neck fan reviews and CNN Underscored's neck fan assessments highlight convenience and effectiveness for brief relief. Battery life and ease of use also help determine how practical such devices are during a journey or working day.

Popular Mechanics' neck fan guide and Forbes' portable air conditioner guide discuss portability, battery performance and usability. These products supplement broader cooling arrangements, providing individual comfort while larger installations serve shared spaces.

Wearable equipment has little effect on the temperature of a plaza or street. Its role is personal relief, while the wider problem of urban heat requires changes to the places where people spend time.

Ground Heat and Data Centers Offer Other Approaches

Japanese manufacturers are also testing ground source heat pumps and advanced air conditioning systems for outdoor and partly enclosed applications. Ground source systems exchange heat with the ground, offering another way to provide cooling while reducing energy requirements.

Field tests of ground heat exchangers in Japan have demonstrated efficient installation and operation, minimal disturbance at the surface and strong thermal performance. Subway stations and underground shopping malls are among the urban settings being considered for integration.

Trials of advanced systems have shown substantial energy savings compared with traditional air conditioning, particularly when smart controls and renewable energy are incorporated. Upfront costs for VRF equipment and ground source heat pumps are higher, although they offer savings over time.

Japan's data center industry is exploring a different form of cooling. KDDI and NTT Data have carried out field tests of liquid immersion cooling, in which equipment is placed in a liquid that carries away heat.

Those tests have shown reductions of up to 97% in the energy used for cooling. The work provides a benchmark for efforts in other sectors to reduce the electricity needed to manage heat, alongside the separate outdoor trials focused on human comfort.

What Cooler Public Spaces Could Change

Shaded and cooled plazas and walkways could give people more opportunities to walk, cycle and take part in outdoor recreation during hot weather. More usable public spaces can also support local businesses and provide places for people to meet.

Japan's outdoor cooling efforts connect urban design with public health. Older people, children and outdoor workers are among the groups that need protection as heatwaves become more frequent and severe. Cooling installations can provide relief in densely populated areas where heat accumulates.

The intended health benefit is a reduction in the risk of heatstroke and other illnesses associated with heat. The field tests described comfort improvements and fewer heat complaints, while public health officials have reported rising illness during severe summer conditions.

Manufacturers are combining engineering with attention to how people use public spaces. A cooling station at a festival, a misted waiting area and a wearable fan serve different needs, even though all aim to make time outside more tolerable.

More comfortable walking and cycling routes could also reduce reliance on cars. The practical goal is to keep public spaces usable during hot periods, giving residents places to travel, rest and gather beyond air conditioned buildings.

Energy, Water and Cost Shape the Next Tests

Japan's electricity grid already faces pressure during summer peaks. Expanding cooling outdoors adds another demand, making efficiency and the use of renewable energy central to the manufacturers' work.

Misting reduces reliance on refrigerants but requires water. Refrigerated systems provide stronger localized cooling but consume more electricity. Cities and operators must weigh those different resource needs against the conditions at each location.

Outdoor equipment must also withstand weather, vandalism and heavy use. Durable construction and regular maintenance are necessary for systems intended to operate in busy public places over repeated summers.

Cost and scale remain practical constraints. Advanced systems can require substantial initial investment, and an installation that works in a small space may require considerable planning and spending before it can serve an entire city district. No schedule for such wider deployment was given.

Japanese manufacturers are continuing research and pilot projects with urban planners and government agencies. Their experience offers lessons for other cities facing rising temperatures: cooling performance, public comfort, electricity demand, water use and maintenance all need to be considered together.

Key Points

• Daikin Industries and Panasonic are testing outdoor cooling in parks, event spaces, festivals and markets as Japan faces increasingly severe summer heat.
• Misting studies in Japanese urban spaces and Mediterranean cities found local temperature reductions of up to 8°C, with the strongest effect within about half a meter of the spray.
• Portable air conditioners provide targeted relief, while wearable devices serve individual users.
• Comparisons in hot climates found that variable refrigerant flow systems can reduce energy use by up to 27% against constant refrigerant flow systems.
• Ground heat exchangers are being considered for urban infrastructure, including subway stations and underground shopping malls.
• KDDI and NTT Data trials of liquid immersion cooling for data centers showed reductions of up to 97% in cooling energy consumption.
• Electricity use, water demand, maintenance, cost and the difficulty of expanding installations remain central challenges.