Coolzy Portable Air Conditioner

The design challenge appeared in Pakistan where indoor temperatures reach 40°C even at night. Traditional air-conditioners cool whole rooms just to keep people cool. With little insulation, refrigeration air-conditioning is energy-intensive and mostly cools concrete, not people. A back-up generator is needed for frequent power outages. In mega-cities with urban heat islands, air-conditioning is becoming essential for human survival. While treaties are driving the change to more climate-friendly refrigerants, providing air-conditioning for all may still cook the planet. The main challenge is affordability. The 2018 Global Cooling Prize yielded some climate-friendly solutions but at twice the cost of current technology.

Coolzy emerged by thinking differently: let’s cool people, not rooms. The key break-through was to understand that focusing cooling on the face and neck is sufficient for people to feel cool. The team developed technology to focus the cooling where it counts. Whereas conventional air-conditioners mix cool air with room air, Coolzy technology avoids mixing by eliminating conditioned air vorticity. The team developed low-cost, easily-cleaned airflow straighteners. Specially designed bed-tents intensify cooling, enabling Coolzy to provide sufficient comfort to sleep with 40°C indoor temperatures using as little as 150 Watts electricity per person while providing sufficient fresh air exchange.

Around 20,000 Coolzys have been sold in Australia and 32 other countries. The Close Comfort group of companies is close to profitable operation. At scale, coupled with rooftop solar, Coolzys could provide affordable cooling for billions of people on a warming planet with acceptable environmental impact. No other commercially-available technology can do that. Hundreds of millions in South Asia struggle to sleep in temperatures well above human physiological limits for months every year. With mass manufacturing to reduce the cost, Coolzy can transform life in most tropical cities, just like conventional air-conditioning transformed Singapore and other countries last century.

Typical domestic battery backup power supplies sold in the largest target markets determined the target power consumption: 350 Watts. High efficiency heat exchangers designed from research papers enabled a relatively high refrigeration CoP, up to 3, minimizing the discharge of waste heat into the room (typical conventional portables achieve 2.7). In major target markets, reinforced concrete construction with minimal insulation and draft sealing ensures that waste heat is effectively absorbed by the building structure. Relatively open vernacular housing allows warm air to escape easily. In compact, well-insulated rooms, an optional “tail” directs warm air to an open window or door using proprietary air jet focusing technology. An optional exhaust pipe is available for users who prefer a curtain (https://www.youtube.com/watch?v=aRSMcEhy9pk). The bed tent has a relatively impermeable lower section that retains cool air and a permeable upper section for fresh air exchange. Cool air enters with sufficiently low velocity and vorticity to form a cool air layer above the mattress about 60 cm thick, with apparent temperature up to 12°C cooler than the room temperature, matching or exceeding the comfort provided by a conventional split air conditioner (https://www.youtube.com/watch?v=I00zjTd4kPo).