Hitachi, Ltd.

Minoru Kano

Kohji Kamejima

Hideki Tanaka

Toshihiko Fukushima

Motokazu Uchida

Michio Yanadori

Hideo Uzuhashi

Kenzo Takeichi

Taisei Hosoda

Yoritsune Abe

Minoru Makita

Akinobu Takemoto

Ryoichi Hisatomi

A servo motor control system for accurately pointing and controlling the speed of a servo motor using a low resolution PWM signal. A PWM command value given in each control operation cycle for driving other servo motors is divided, and output to a power control device operating signal generation circuit.

Method and apparatus for controlling a servo motor

A heat exchanger for cooling is immersed in a vessel for storing heat filled with a heat-storing material of latent heat type. The heat exchanger for cooling is positioned at an upper level in the vessel when a heat-storing material having a higher specific gravity in a crystal state than in a liquid state, such as calcium chloride hexahydrate, is used, whereas at a lower level in the vessel when a heat-storing material having a lower specific gravity in a cystal state than in a liquid state such as water, is used. Crystals of a heat-storing material formed and deposited on the outer periphery of the heat exchanger for cooling when the apparatus for storing heat is in operation are accumulated in the vessel for storing heat as blocks.

Apparatus for storing heat

In a refrigerating and air-conditioning system provided with a heat storage tank, variation patterns of load and weather conditions are predicted. On the basis of the predicted values, optimum outputs of a refrigerating machine at individual time points within a predetermined operation period are determined for possible water temperatures of the heat storage tank and stored in a memory. In accordance with the actual water temperature of the heat storage tank, the optimum output of the refrigerating machine is retrieved from the memory and utilized for the operation thereof.

Method of operating refrigerating machine

In an operating method for refrigerating machines which is disclosed, a variation pattern of an air-conditioning load on a prearranged day for refrigerating operation and a variation pattern of ambient temperature on the prearranged day are predicted. A period for refrigerating operation on that day is properly divided into plural time intervals. Priority ranking is allotted to those time intervals on the basis of the ambient temperature predicted. The refrigerating machine is operated in accordance with an operating pattern set on the basis of the priority ranking.

Operating method for refrigerating machine

A control system for an air conditioner having detectors for detecting at least the radiation temperature in a room or controlled space, a device for setting a desired room air parameter in response to the detected radiation temperature, and a controller for controlling the air conditioner in accordance with the desired room air parameter.

Growing community of inventors

Shimoinayoshi, Japan

Minoru Kano