Mitsubishi Plastics, Inc. ("MPI"; head office: Chuo-ku, Tokyo; president: Hiroshi Yoshida) and Mayekawa Manufacturing Co., Ltd. (head office: Koto-ku, Tokyo; president: Akira Naka) have become the first in the world to achieve successful operation of a next-generation adsorption chiller utilizing heat from the sun that uses a zeolite[1] based desiccant. This was part of the Project for the Research and Development of New Systems for Utilizing Solar Energy contracted from fiscal 2005 to 2007 by NEDO[2] to Mayekawa Manufacturing, which has a long and proven record of accomplishment in the manufacture and sale of conventional adsorption chillers using silica gel[3] based desiccants. MPI's AQSOA™ zeolite-based desiccant was mounted in an adsorption chiller manufactured by Mayekawa Manufacturing, and the stable performance of the system was verified in field trials. The stable operation of an adsorption chiller that uses sunlight will help mitigate global warming by enabling the sustained reduction of CO2 emissions.

The first next-generation adsorption chiller using solar heating was introduced at a health and welfare facility in Nagano prefecture

An adsorption chiller is an industrial chilling/cooling device that is friendly to the global environment, as it does not use CFCs, and it uses water as its coolant, and a dedicated desiccant for adsorption, and does not utilize mechanical compressions like other types of chillers. It utilizes vaporization heat captured from the surrounding air as water evaporates, making it possible to continually create cooling (chilled water) of 3 to 25℃, by making effective use of waste heat (heated water) at temperatures of 60 to 100℃. AQSOA™ is a new functional desiccant designed and developed by the Mitsubishi Chemical Group Science and Technology Research Center, Inc. It is made from a safe mineral using zeolites that have several times more adsorptive capacity than conventional silica gel basted desiccants, and features the ability to adsorb and release water vapor extremely efficiently, even at the relatively low temperature ranges of waste heat (50 to 80℃).

The companies have achieved stable operation of a next-generation adsorption chiller using solar heating; this chiller is able to generate two to three times the cooling (chilled water) per unit volume from water heated using the sun's energy than conventional adsorption chillers using silica gel. In fact, calculations from the results of field tests of a pilot system (70 kW) show that if an adsorption chiller were manufactured with 350 kW (100 US refrigerating tons) of cooling capacity, a next-generation adsorption chiller using AQSOA™ would have 70% the desiccant mass of a conventional adsorption chiller using silica gel, have 42% of the adsorption volume, and 44% the mass of the adsorption chiller module device, achieving reductions for each of these properties. Meanwhile, it could reduce CO2 emissions by 64% from those of a conventional air-cooled chiller for chilled water manufacturing. The new adsorption chiller could also use waste heat from factories and the like at lower temperatures of 80℃ or less; such waste heat has not been used widely until now, because these temperatures were too low for efficient operation. This makes it possible to create such applications as cooling systems powered by solar heating, and chilled water supply systems for energy-efficient processing using waste heat from factories that had not been used before. This, coupled with the fact that such systems use water as their coolant rather than CFCs, makes this a truly next-generation adsorption chiller that is friendly to the global environment.
MPI will set up an organization for the manufacture and sale of AQSOA™ functional desiccant, as well as parts and materials using it, such as heat exchangers. It will also cultivate markets for a wide range of applications as desiccants or heat exchangers that help conserve energy and reduce CO2 emissions; examples include chemical plants where waste heat is available, and building HVAC systems using solar energy. Meanwhile, Mayekawa Manufacturing's current "Natural Five Plan"[4] has positioned this adsorption chiller as the optimum device that can be applied to all of the company's target markets (e.g. building A/C, food plants, chemical plants, and beverage plants) for 3 to 25℃ cooling (chilled water) using 60 to 100℃ waste heat (heated water), and it will actively market it through its nationwide network of branches and sales offices.

Notes
[1] Zeolite
 A general term for an aluminosilicate with micropores in the crystal.
[2] Silica gel
 This substance is used for a wide range of applications, including food desiccants, home dehumidifiers, and in industry as an agent for removing carbonic acid gas.
[3] New Energy and Industrial Technology Development Organization (NEDO)
 NEDO is Japan's largest and most central research and development institution. It researches, develops, popularizes, and promotes industrial, energy, and environmental technologies.
[4] Natural Five Plan
This is a plan by Mayekawa Manufacturing to provide its customers with efficient hot-water, heating, A/C, chilling, refrigeration, and freezing systems using only five types of natural coolants that are friendly to the global environment (water, air, ammonia, carbon dioxide, and hydrocarbon gases), and without using any CFC-based coolants, in order to utilize all temperatures in the range of +90℃ to –100℃.

 

■Contact Information
Regarding AQSOA™ zeolite-based functional desiccant:
Public Relations Section
General Administration Dept.
Mitsubishi Plastics, Inc.
Tel: +81-3-3279-3800

Regarding next-generation adsorption chiller:
Public Relations Section
Mayekawa Manufacturing Co., Ltd.
Tel: +81-3-3642-8185