Hitachi, Ltd.

Other

Hitachi Cable, Inc.

Masaaki Itoh

Mari Uchida

Toshihiko Fukushima

Hideyuki Kimura

Hiroshi Kogure

Takeo Tanaka

Toshio Hatada

Masakatsu Hayashi

Hiroaki Matsushima

Minetoshi Izushi

Tadao Otani

Akira Tomita

Minoru Sato

Naoki Shikazono

Mitsuo Kudoh

Yuichi Ishikawa

Kensaku Oguni

Wataru Nakayama

Takao Senshu

Izumi Ochiai

Hiromu Yasuda

Hirokiyo Terada

Kunio Fujie

Mitsutaka Shizuya

Yoshihiko Mochizuki

Masahiro Miyagi

Takehiko Yanagida

Tamio Innami

Tatsuya Sugiyama

Makoto Nagai

Chie Kobayashi

Naoto Katsumata

Mituo Kudo

Sumiyoshi Takeda

Yukio Kitayama

Masanori Musoh

Mituo Kudoh

Syoji Takaku

Tsuneyoshi Takasuna

Mituo Kodoh

Kenji Iino

Hiromi Tsuji

To provide a high heat transfer performance with a heat transfer pipe used to a condenser and an evaporator in a refrigerating cycle using a refrigerant mixture, the heat transfer pipe includes main grooves and auxiliary grooves each formed on the inner surface of the heat transfer pipe with the main grooves intersecting the auxiliary grooves, wherein the main grooves are separate by ridges, and the ridges are divided into ribs by the auxiliary grooves, and wherein a length of the ribs formed along the direction of the main grooves is made longer than the length of the ridges, a width of the auxiliary grooves is made smaller than the length of the ribs and further the auxiliary grooves are formed in a direction where a pressure gradient in the heat transfer pipe is reduced.

Heat transfer pipe for refrigerant mixture

A heat exchanger composed by overlapping a plurality of heat exchanger units each of which is formed by inserting a plurality of fins over one or a plurality of heat transfer tubes. The fins are worked so that a pair of opposed fins of the overlapped heat exchanger units are brought into contact with each other at one or more points. This heat exchanger constitutes an air conditioner when the heat exchanger units are overlapped in a direction of gravity.

Heat exchanger and air conditioner using same

In a heat transfer tube for a zeotropic refrigerant mixture, the inner surface of the tube in which the zeotropic refrigerant mixture flows is formed with grooves having cross portions where the grooves intersect with each other, or the inner surface of the tube is formed with a plurality of independent projections. Thus, concentration boundary layers generated in the zeotropic refrigerant mixture are stirred to reduce the thickness of the concentration boundary layers, thereby decreasing the diffusion resistance and promoting the stirring effect. Consequently, there can be provided a heat transfer tube for a zeotropic refrigerant mixture which exhibits a high heat transfer performance, and a heat exchanger of a cross-fin tube type, a refrigerator and an air conditioner which include such heat transfer tubes.

Refrigeration cycle

A heat exchanger, in which a plurality of fins formed on either an internal or an external face of a heat transfer tube, wherein each of the plurality of fins has a first portion including a fin top and a second portion including a fin root, and wherein the first portion has a ridgeline formed in a raised and recessed shape, or in a wave-like or corrugated shape, and the second portion has a substantially straight outline in a fin longitudinal direction in a cross section parallel to either the internal or the external face on which the plurality of fins are formed.

Heat exchanger

An air-conditioner of a heat pump type includes a refrigeration cycle including an interior heat exchanger, an exterior heat exchanger, a compressor, a four-way valve, and an expansion mechanism, and a non-azeotrope refrigerant composed of not less than two kinds of refrigerants is used as a working medium. A refrigerant path in each of the interior and exterior heat exchangers is divided into a group of first refrigerant passages located at a region where a proportion of the liquid-phase refrigerant is large and a group of second refrigerant passages located at a region where a proportion of the liquid-phase refrigerant is small. At least part of the group of first refrigerant passages of each of the interior and exterior heat exchangers is located at the windward side. Heat transfer tubes of the group of first refrigerant passages of each of the interior and exterior heat exchangers are smaller in flow-passage cross-sectional area than those of the corresponding group of second refrigerant passages.

Air-conditioner employing non-azeotrope refrigerant

A fin-tube type heat exchanger has parallel heat transfer tubes and a stack of a plurality of plate fins mounted on the tubes. Heat exchange is conducted between a first fluid flowing through the tubes and a second fluid flowing through the stack across each of the fins. Each fin has flat tube-mounting portions spaced in the longitudinal direction of the fin and formed with tube-mounting holes and a louver section disposed between each adjacent pair of tube-mounting portions. The louver section has elongated slats extending longitudinally of the fin and having side edges each spaced from an adjacent side edge of an adjacent slat. The slats are classified into two groups in respect of the cross-sectional shape. The slats of one group have generally flat cross-sections to reduce the resistance of the fin to the flow of the second fluid through the stack and are disposed in planes offset from the plane of the tube-mounting portions. The slats of the other group have V-shaped or inverted V-shaped cross-sections to increase stiffness of the fin in the longitudinal direction thereof.

Fin-tube type heat exchanger

Disclosed is an air conditioner and, in particular, an air conditioner which is capable of blowing out warm air in heating mode. In the air conditioner of this invention, the condenser is thermally separated into an air-upstream-side and an air-downstream-side heat exchanger, and the heat exchange capacity of the air-downstream-side heat exchanger is adjusted, so that, under preset operating conditions, the entire refrigerant in the air-downstream-side heat exchanger can be kept in the superheated-gas phase, thus making it possible to blow out warm air having a temperature higher than the condensation temperature. Further, the refrigerant temperature at the outlet of the air-downstream-side heat exchanger is measured by a temperature sensor, and the revolving speed of the compressor, the revolving speed of the fan, etc., is so controlled that the temperature measured is kept at a level higher than the condensation temperature. Thus, under all operating conditions, the entire refrigerant in the air-downstream-side heat exchanger can be kept in the superheated gas phase, thereby making it possible to blow out warm air having a temperature higher than the condensation temperature.

Air conditioner and heat exchanger used therein

A fin-and-tube type heat exchanger is disclosed in which the height of each raised, slotted louver from a fin base portion continuously changes in a direction crossing at right angles both the direction of the air flow and the direction of lamination of fins, and two or three kinds of such louver pairs, each consisting of louvers symmetric with each other with respect to the fin base portion, are arranged regularly.

Fin-and-tube type heat exchanger

A fin assembly for heat exchangers used in air conditioners or the like. The fin assembly is formed from a thin plate material which is bent and wound to have a plurality of alternating turns each of which constitutes a fin. The fin is provided with a multiplicity of louvers cut-out and raised from the major plane thereof. The fins are inclined at an angle .theta. which is 30.degree. or smaller to the direction of flow of the gas entering the fin assembly, while the louvers are inclined at an angle .gamma. which is 20.degree. or smaller to the direction of flow of the gas entering the fin assembly in the direction opposite to the direction of inclination of the fin plates.

Fin assembly for heat exchangers

A heat exchanger fin according to the invention has a multiplicity of fins arranged substantially in parallel with the direction of air flow and at least one heat transfer tube to which said fins are connected in a heat conducting relation. A multiplicity of louvers inclined by a small angle to the direction of air flow are formed in said fins. According to this construction, it is possible that the air as a whole can flow substantially straight across the heat exchanger and can strongly collide with all louvers, thereby to ensure a reduced flow resistance encountered by the air flow, as well as improved heat transfer performance of the heat exchanger.

Heat exchanger fin

In a crossed fin-tube type heat exchanger wherein tubes are attached at right angles to a large number of fin elements arranged in parallel with one other, the surfaces of these fin elements are roughened to have an unevenness satisfying a relation

Method of making fin elements for heat exchangers

A heat transfer pipe for use in a heat exchanger such as air conditioner, freezer and boiler, wherein grooves are formed in the inner wall surface of the pipe, which are by far finer in size than the grooves that have been provided for the purpose of increasing the heat transfer area in general, and slanting relative to the axis of pipe, to thereby improve the heat transfer rate without increasing the pressure loss caused to the fluid flowing through the pipe.

Heat transfer pipe

Growing community of inventors

Tsuchiura, Japan

Masaaki Itoh