Refrigeration – Automatic control – Refrigeration producer
Reexamination Certificate
1999-05-17
2002-12-31
Tanner, Harry B. (Department: 3744)
Refrigeration
Automatic control
Refrigeration producer
C062S228400
Reexamination Certificate
active
06499308
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an apparatus for controlling a compressor, a heat exchanger for evaporation, and a heat exchanger for condensation in a refrigeration cycle constituting a refrigerating air conditioner and a method of controlling the refrigeration cycle.
2. Discussion of Background
FIG. 14
 schematically shows a refrigeration circuit of a conventional multi-chamber type air conditioner disclosed in JP-A-8-2534926. In 
FIG. 14
, numerical reference 
31
 designates an outdoor unit; numerical reference 
32
 designates a variable capacity compressor; numerical reference 
33
 designates a four-way valve; numerical reference 
34
 designates an outdoor heat exchanger; numerical reference 
37
 designates a distributor; numerical references 
41
a 
through 
41
c 
designate three indoor units; numerical references 
42
a 
through 
42
c 
designate indoor electronic expansion valves; numerical references 
43
a 
through 
43
c 
designate electromagnetic switching valves; numerical references 
44
a 
through 
44
c 
designate electromagnetic switching valves; numerical reference 
45
 designates a controller; numerical reference 
46
 designates an outdoor blower; numerical reference 
47
 designates an electronic expansion valve; numerical references 
48
a 
through 
48
c 
designate indoor heat exchangers; numerical reference 
49
 designates a gas-liquid separator; numerical references 
51
 and 
52
 designate connection pipes for connecting the outdoor unit 
31
 to the distributor 
37
; numerical reference 
53
 designates a high-pressure pipe in the distributor 
37
; numerical reference 
54
 designates a low-pressure pipe in the distributor 
37
; numerical reference 
55
 designates an intermediate pressure pipe; numerical reference 
56
 designates a four-way valve; numerical reference 
57
 designates an accumulator; numerical reference 
58
 designates a pressure detector for a high pressure; and numerical reference 
59
 designates a pressure detector for a low pressure.
The distributor 
37
 and each of the indoor units 
41
a 
through 
41
c 
are connected by two pipes. The indoor units 
41
a 
through 
41
c 
are composed of the indoor heat exchangers 
48
a 
through 
48
c 
and the electronic expansion valves 
42
a 
through 
42
c, 
wherein the electronic expansion valves 
42
a 
through 
42
c 
are connected to the intermediate pressure pipe 
55
, and the indoor heat exchangers 
48
a 
through 
48
c 
are connected to the low-pressure pipe 
54
 and the high-pressure pipe 
53
 through the electromagnetic switching valves 
43
a 
through 
43
c 
and 
44
a 
through 
44
c. 
Further, the pressure detectors 
58
 and 
59
 are installed in the outdoor unit 
31
, wherein detection signals from the pressure detectors are inputted in the controller 
45
. The controller 
45
 controls a capability of exchanging heat between a refrigerant circulating in piping and the outdoor heat exchanger 
34
 using the compressor 
32
, the four-way valve 
33
, and the blower 
46
.
In the next, operation will be described. A case that the indoor unit 
41
a 
is in a heating mode and the indoor units 
41
b 
and 
41
c 
in a cooling mode will be described. A high-temperature high-pressure gas refrigerant compressed by the compressor 
32
 passes through the four-way valve 
33
 and is partially condensed by the outdoor heat exchanger 
34
 to be transformed into a two-phase refrigerant. Thereafter, the refrigerant passes through the high-pressure connection pipe 
51
 and flows into the distributor 
37
 located in a room.
The two-phase refrigerant in the distributor 
37
 passes through the four-way valve 
56
 and is separated into a gas and a liquid by the gas-liquid separator 
49
. Thus obtained high-pressure gas refrigerant flows into the indoor unit 
41
a 
through the electronic switching valve 
44
a, 
and dissipates heat to be condensed by the indoor heat exchanger 
48
a. 
Thereafter, the refrigerant flows into the intermediate pressure pipe 
55
 through the electronic expansion valve 
42
a 
and joins with a liquid refrigerant flowing into the intermediate pressure pipe. from a liquid-phase portion through the electronic expansion valve 
47
 and flows into the indoor units 
41
b 
and 
41
c. 
In the indoor units 
41
b 
and 
41
c, 
the refrigerant is respectively changed to have a low pressure by the electronic expansion valves 
42
b 
and 
42
c 
and is endothermically evaporated by the indoor heat exchangers 
48
b 
and 
48
c. 
Thereafter, it joins with the low-pressure pipe 
54
 through the electromagnetic switching valves 
43
b 
and 
43
c. 
Further, it passes through the four-way valve 
56
 and circulates by passing through the low-pressure connection pipe 
52
, the four-way valve 
33
, and the accumulator 
57
 and returning to the compressor 
32
. As described, a refrigeration circuit for simultaneously heating and cooling, in which a cooling operation is conducted in the indoor heat exchanger 
48
a 
and a heating operation is conducted in the indoor heat exchangers 
48
b 
and 
48
c, 
is realized.
In the above refrigeration circuit, a high pressure discharged from the compressor 
32
 and a low pressure sucked by the compressor 
32
 are detected by the pressure detector 
58
 provided in the high-pressure pipe in the outdoor unit 
31
 and the pressure detector 
59
 provided in the low-pressure pipe, and the result of this detection is transmitted to the controller 
45
. The controller 
45
 compares each detected value respectively with preset high-pressure or low-pressure target value after receiving signals transmitted from the detectors 
58
 and, 
59
. Further, the controller 
45
 calculates a requisite capacity of the compressor 
32
 based on a result of this comparison and a requisite capacity of the outdoor heat exchanger 
34
 based on a result of this calculation. Further, the controller 
45
 controls a capacity of compressor 
32
 based on the result of this calculation and simultaneously controls a capability of exchanging heat in the outdoor heat exchanger 
34
 by adjusting the revolutional numbers of the blower 
46
.
Further, when a variation of a load is estimated large, a capacity of the compressor 
32
 and a capacity of the outdoor heat exchanger 
34
 are controlled and simultaneously the four-way valve 
33
 is switched based on determination of whether or not the outdoor heat exchanger 
34
 is used as a condenser of heat dissipator or as an evaporator of heat absorber from the result of calculation, whereby a drastic variation of the load is managed.
By such a control, it is possible to deal with changes of a load on an outdoor unit side in response to environmental conditions of weather and a climate, opening and closing of side doors of the indoor units 
41
a 
through 
41
c, 
a change of a preset indoor temperature, and a change of the load of the indoor unit caused by switching between cooling and heating modes.
In controlling thus constructed conventional multi-chamber type air conditioner, the high-pressure target value and the low-pressure target value necessary for calculating a degree of controlling the compressor, of the outdoor heat exchanger, and of the four-way valve were fixedly preset in designing the refrigeration cycle and were constant regardless of a preset value of indoor air temperature and an outdoor air temperature.
Specifically, the high-pressure target value and the low-pressure target value were set so as to be able to deal with a large load for obtaining a general purpose apparatus which can deal with any load.
Since the method of controlling the conventional multi-chamber type air conditioner had the above-mentioned structure and operation, the air conditioner was not always energy-saving as a whole as long as the capability for exchanging heat of the indoor heat exchangers 
41
a 
through 
41
c 
were not controlled by the controller 
45
 in the outdoor unit 
31
.
Further, energy consumption of the compressor 
32
, which occupied the largest ratio in the entire energy consumption of the air conditioner, was substantially constant irre
Inoue Seiji
Miyamoto Moriya
Nonami Keiji
Burns Doane , Swecker, Mathis LLP
Mitsubishi Denki & Kabushiki Kaisha
Tanner Harry B.
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