Press Release Back Number(2006)

Joint development and sale of low-cost,compact high-performance air-conditioning heating tower
- Heating tower capable of both heating and cooling using water chillers -

January 26, 2006
Kuken Kogyo Co., Ltd.
Chubu Electric Power Co., Inc.
The Tokyo Electric Power Company, Inc.
The Kansai Electric Power Company, Inc.

Kuken Kogyo Co., Ltd., Chubu Electric Power Co., Inc., the Tokyo Electric Power Company, Inc., and the Kansai Electric Power Company, Inc. have jointly developed a high-performance heating tower*1 (cooling capacity: 454 kW/heating capability: 235 kW) with low costs and a compact size, for use in air-conditioning equipment in office buildings, factories, and other facilities.


Today, Kuken Kogyo launched sales of this product with an annual sales goal of sales of at least 500 units. The price of a single unit is 5 million yen.


In the field of large-scale air-conditioning equipment for office buildings, factories, and other facilities, efforts in recent years to reduce energy costs by reducing initial costs and promoting improved efficiency have combined with growing interest in global environmental issues to create demand for environmentally sensitive, energy-efficient products with low carbon-dioxide emissions.


Until now, despite their superiority in terms of low energy consumption and capacity to operate at high efficiency, heating-tower air-conditioning systems combined with water chillers*2 have generally meant high initial costs, as well as the cost of installing defroster equipment.


These newly developed heating towers for use with air-conditioning equipment make it possible to use the low-cost high-efficiency water chillers previously used for cooling for both heating and cooling.


Improving the performance of the internal heat exchangers makes possible compact dimensions, which in turn keeps materials costs low. This equipment has also achieved massive reductions in initial costs through the standardization of the components used. Furthermore, the newly developed internal defroster equipment has massively simplified winter use of defroster equipment, slashing installation costs.


This equipment has the following strong points:


1. Low cost and compact dimensions

In addition to using high-performance fins*3 in its heat exchangers that are capable of efficiently exchanging heat with outside air, this device internally circulates a low-viscosity antifreeze*4 liquid with high levels of heat-transfer performance, in this way increasing heat-exchange efficiency. As a result, it is able to demonstrate in a more compact size (with installation surface area decreased by 10% from that of previous equipment from Kuken Kogyo) capabilities similar to those of previous, larger equipment. In addition, it has achieved thorough reductions in manufacturing costs through standardization of components and materials. These advances have cut initial costs by some 60%, compared to earlier versions from Kuken Kogyo.


2. Industry-leading operating efficiency

Combined use with high-efficiency water chillers makes it possible for the system to achieve COP*5 values of 4.7 for cooling and 3.1 for heating. These values represent the industry's highest operating efficiency for air-conditioning systems designed for office buildings, factories, and other facilities.


3. Simplified defrosting

In winter, heating towers installed outdoors must be defrosted to remove the frost that collects on heat exchangers. Previous defrosting methods required external tanks to store storing preheated antifreeze and complex plumbing, making installation costly. But this equipment includes compact defroster units and doesn't need external defroster equipment. In addition, it features an outside-air defroster mode that adjusts the defrosting method based on the air temperature detected outside, thereby reducing energy consumption.


In the past, Chubu Electric Power, Tokyo Electric Power, and Kansai Electric Power have worked to meet the diverse needs of their customers by providing optimal solutions and developing a range of electrical devices. The companies believe that this new equipment will satisfy an even wider spectrum of customers due to its achievements in areas such as low initial costs and compact dimensions.


The new equipment will be introduced at HVAC&R Japan 2006*6 (organized by the Japan Refrigeration and Air Conditioning Industry Association), which is scheduled to begin February 7.



*1 Heating tower:
Also known as a heating/cooling tower, a heating tower is a device installed outdoors for use primarily in large-scale air-conditioning systems such as zone heating and air-conditioning. When used for heating, it functions as a heating tower by absorbing heat from the atmosphere. When used for cooling, it functions as a cooling tower by releasing heat into the atmosphere.


*2 Water chiller:
A water chiller (heat-pump chiller) is used to generate cool water and hot water in air-conditioning systems for use in office buildings, factories, and other facilities. Water chillers are generally more efficient and less expensive to operate than air-cooling. Previously, water chillers were used primarily for cooling alone. In rare cases, they have been used for heating.


*3 High-performance fins
Thin sheet fins are installed on the exterior (outside-air) side of the heat-exchanger tubes in the tower to maximize the heat-transfer surface area on the outside-air side and to allow efficient heat exchange between the atmosphere and the antifreeze. This design replaces traditional flat fins with wave-shaped fins, which are more efficient for heat-exchange purposes.


*4 Low-viscosity antifreeze:
This refers to a low-viscosity liquid that does not freeze even at temperatures below zero degrees Celsius. In heating equipment, low-viscosity antifreeze absorbs heat from the outside air by circulating a liquid inside the tower at a temperature below that of the outside air. Since the temperature of this liquid will sometimes fall below zero degrees Celsius, antifreeze is used. The lower the viscosity of this liquid, the better its heat transfer performance and the more readily it absorbs heat. This equipment uses low-viscosity antifreeze, the viscosity of which is less than one-third that of the antifreeze used in previous equipment (at a temperature of 9.5 degrees Celsius).


*5 System COP:
Coefficient of performance (COP) refers to the value achieved by dividing heating and cooling capabilities by power consumption. The greater this value, the lower a system's energy consumption. System COP is calculated from the power consumption of the water chiller, the antifreeze pump, and the heating tower. (The COP figures used herein are based on testing by Kuken Kogyo.)

Conditions for COP calculations (calculated based on JIS B8613 using the following outside-air and water temperatures):

  • • System COP 4.7 (cooling): outside dry-bulb temperature of 35°C; outside wet-bulb temperature of 24°C; water supply temperature of 7°C; cooled-water temperature of 12°C
  • • System COP 3.1 (heating): outside dry-bulb temperature of 7°C; outside wet-bulb temperature of 6°C; water supply temperature of 45°C; cooled-water temperature of 40°C
    (Each of the above assumes use of the Hi-F Mini 150 [COP: 5.6] from Kobe Steel, Ltd.)

*6 HVAC&R Japan 2006:
34th heating, refrigeration, and air-conditioning trade show
Dates and times: 10:00 a.m. - 5:00 p.m. (4:00 p.m. on the final day), Tuesday, February 7 - Friday, February 10, 2006
Venue: West Hall (Halls 1 and 2), Tokyo International Exhibition Center (Tokyo Big Sight)
Organizer: Japan Refrigeration and Air Conditioning Industry Association (http://www.jraia.or.jp/)
Admission: free of charge (registration required)


Please address any inquiries concerning this product to:

Nagoya Branch, Kuken Kogyo Co., Ltd.(attn.: Noriyoshi Yokoyama; tel. 052-953-3100)

HT Development Department, Engineering Division, Kuken Reiki Co., Ltd. (attn.: Masahiro Inoue; tel. 0949-32-1212)