JP2013137124A - Refrigeration cycle device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To efficiently remove moisture and non-condensable gas, particularly, oxygen and carbon dioxide in air mixed during construction work on site, to shorten a construction time by eliminating special work even in particular when a connection pipe is long or there are many use-side heat exchangers to be connected, to stably start a compressor, and to improve reliability and performance of a refrigeration cycle device.SOLUTION: In a refrigeration cycle device which is configured by sequentially connecting the compressor, a heat source-side heat exchanger, a first expansion device, a liquid-side connection pipe, a second expansion device, a use-side heat exchanger, and a gas-side connection pipe, an adsorbent which adsorbs at least oxygen in the non-condensable gas and a drier which adsorbs moisture contained therein are arranged between the first expansion device and the second expansion device, a gas pump is provided is provided through an on-off valve in at least one of the liquid-side connection pipe and the gas-side connection pipe, and the gas pump is operated before a refrigerant is introduced into the liquid-side connection pipe and the gas-side connection pipe.

Description

  The present invention relates to a refrigeration cycle apparatus such as an air conditioner or a refrigerator using a refrigeration cycle.

  In the construction method of connecting the unit including the heat source side heat exchanger and the unit including the use side heat exchanger with connection piping, moisture and non-condensable gases (oxygen, nitrogen, carbon dioxide, etc.) in the atmosphere are connected and used. It remains in the unit including the side heat exchanger, and possibly in the unit including the heat source side heat exchanger. When a large amount of moisture is mixed into the unit, it binds to the refrigerant molecules, generates a hydrate at the low temperature part, and clogs an expansion device such as a capillary. Therefore, lubrication of the refrigerant and the refrigerating machine oil is hindered, and the temperature of the compressor rises abnormally, or the refrigerating machine oil amount necessary for lubricating the compressor sliding portion cannot be secured.

  Also, when ester oil is used as refrigerating machine oil, or when ester additives are added to refrigerating machine oil, these ester compounds are hydrolyzed to produce acid, and oxygen is enclosed in the unit in advance. The refrigeration machine oil is oxidized and deteriorates. Further, carbon dioxide gas reacts with moisture to generate carbonic acid (acid). The acid increases the wear of the compressor bearing, accelerates the deterioration of the refrigerating machine oil, or corrodes the copper pipe, elutes copper ions, and precipitates copper (copper plating phenomenon) at the compressor bearing. This may cause abnormal noise.

  Therefore, it is necessary to prevent moisture, oxygen, and carbon dioxide from circulating through the refrigeration cycle by discharging moisture, oxygen, and carbon dioxide outside the machine or not bringing them into the machine. The portion where moisture and non-condensable gas are mixed is evacuated by a vacuum pump, and the moisture and non-condensable gas are discharged outside the apparatus.

  However, in the method of evacuating with a vacuum pump at the time of on-site construction, the contents of the space to be evacuated in a system where the piping length is long and there are multiple units including the use side heat exchanger connected to the piping The product becomes large, the time for evacuation becomes long, and about 2 to 3 hours are required.

  Therefore, as a method for efficiently removing moisture and non-condensable gas in the refrigeration cycle, especially oxygen and carbon dioxide, shortening the construction time, and further improving the reliability, the first filter filled with the desiccant A refrigeration system having a configuration of a second filter filled with a reactive non-condensable gas removing agent is known, and is described in Patent Document 1, for example.

JP-A-4-302967

  Particularly in the above-described prior art, the non-condensable gas remaining in the connection pipe and the use side heat exchanger circulates in a gas state without phase change in the refrigeration cycle. The refrigerant condenses in the condenser and changes to a liquid single phase or a state with a small degree of cuteness. However, since the non-condensable gas is not condensed, the liquid pipe always has two phases. When the degree of opening at the throttle device at the evaporator inlet is constant, the degree of pressure of the fluid at the inlet of the evaporator inlet varies depending on the amount of non-condensable gas mixed in, so the pressure loss at the throttle device changes. To do.

  In particular, when the length of the connection pipe that increases the amount of non-condensable gas is mixed, and when the number of connected use-side heat exchangers is large, the degree of fluidity at the inlet of the expansion device at the evaporator inlet is remarkably increased. For this reason, the pressure loss in the expansion device increases.

  Furthermore, when the compressor is started, the opening degree of the throttle device at the evaporator inlet is a predetermined opening degree, and when the amount of non-condensable gas increases, the degree of fluidity of the inlet of the throttle device at the evaporator inlet becomes remarkably high. As the pressure increases, the pressure loss in the expansion device increases, and the compressor suction pressure becomes 0 [MPa (abs)], which reduces the reliability of the compressor. Therefore, there is a possibility that the compressor cannot be started and the refrigeration cycle apparatus cannot be operated.

  The object of the present invention is to solve the above-mentioned problems of the prior art and efficiently remove moisture and non-condensable gas in the atmosphere and particularly oxygen and carbon dioxide mixed in the field construction work, and particularly, the length of the connecting pipe is long, or An object of the present invention is to provide a refrigeration cycle apparatus capable of eliminating special work and shortening construction time even when the number of connected use side heat exchangers is large.

  In order to solve the above problems, for example, the configuration described in the claims is adopted. The present application includes a plurality of means for solving the above-described problems. For example, a compressor that compresses a refrigerant, a heat source device side heat exchanger, a first expansion device, a liquid side connection pipe, a second In a refrigeration cycle apparatus configured by sequentially connecting an expansion device, a use side heat exchanger, and a gas side connection pipe, a non-condensable gas is interposed between the first expansion device and the second expansion device. An adsorbent that adsorbs at least oxygen and a dryer that adsorbs moisture, and a gas pump is connected to at least one of the liquid side connecting pipe or the gas side connecting pipe, and the gas pump is connected to the liquid side connecting pipe Or by operating before a refrigerant | coolant is introduce | transduced into the inside of the said gas side connection piping, the non-condensable gas inside these connection piping is open | released to air | atmosphere.

According to the present invention, atmospheric moisture and non-condensable gas mixed in the field construction work, particularly oxygen and carbon dioxide gas are reduced by the gas pump and then adsorbed by the non-condensable gas adsorbent disposed in the refrigeration cycle. Therefore, the number of processes does not increase with respect to the conventional piping work, and clogging of the refrigeration cycle and deterioration of refrigeration oil can be efficiently suppressed. Therefore, it is not necessary to perform evacuation even when the length of the connecting pipe is long or the number of use side heat exchangers to be connected is large, so that the construction time can be shortened.
Problems, configurations, and effects other than those described above will be clarified by the following description of embodiments.

The cycle system diagram which shows one embodiment by this invention. The cycle system diagram which shows other embodiment by this invention. The cycle system | strain diagram which shows other embodiment by this invention. The graph which analyzed the abundance of the non-condensable gas in a refrigerating cycle. The graph which showed the minimum compressor suction side pressure after the compressor start by the amount of non-condensable gas. Graph showing the relation between the vacuum p ₂ of the inner and outer volume ratio β and the connection pipe and the utilization-side heat exchanger.

  Embodiments of the present invention will be described below with reference to the drawings.

In the present embodiment, the refrigeration cycle that can start the compressor stably without performing evacuation even when the length of the connecting pipe is long or the number of connected use side heat exchangers is large. An example of the apparatus will be described. FIG. 1 is a cycle system diagram showing this embodiment. In the local construction work, after installing the outdoor unit 40a and the indoor units 20a and 20b, the outdoor unit 40a and the indoor units 20a and 20b are connected using the connection pipes 7 and 8 at the time of construction. The outdoor unit 40a is shipped with refrigeration oil sealed at the time of manufacture, vacuumed to a pressure p ₁ or less, and filled with a refrigerant. Air (non-condensable gas) and moisture in the air remain in the connection pipes 7 and 8 and the indoor units 20a and 20b. At this time, the pressure in the connection pipes 7 and 8 and the indoor units 20a and 20b is atmospheric pressure.

  In the present embodiment, the gas pump 50 built in the outdoor unit 40a is connected in the vicinity of the gas blocking valve 9 of the gas side connection pipe 8 via the gas pump connection pipe 52a and the on-off valve 51a. You may connect in the liquid blocking valve 6 vicinity. The on-off valve 51a may be an electric valve that opens and closes according to the operation of the gas pump 50, or a valve that is manually opened and closed. The on-off valve 51a operates by opening the on-off valve 51a before driving the gas pump 50, and closing the on-off valve 51a after operating the gas pump 50 for a predetermined time.

  The power source for driving the gas pump 50 is taken out from the substrate of the outdoor unit 40a, and the operation and stop of the gas pump 50 are controlled by the substrate of the outdoor unit 40a. Further, when the gas pump 50 is operated, the second expansion devices 21a and 21b are set to be fully open. Thereby, the non-condensable gas in the connection pipe on the side where the gas pump 50 is not connected can be discharged to the atmosphere.

  When the second expansion devices 21a and 21b cannot be set to fully open, as shown in FIG. 2, the gas pump 50 is connected to the gas blocking valve 9 in the vicinity of the gas blocking valve 9 with a gas pump connection pipe 52a and an on-off valve 51a. In addition, the liquid side connection pipe 7 may be connected to the vicinity of the liquid blocking valve 6 via a gas pump connection pipe 52b and an on-off valve 51b.

  The gas pump 50 operates immediately before introducing the refrigerant into the connection pipes 7 and 8 and the indoor units 20a and 20b, and discharges the air in the connection pipes 7 and 8 and the indoor units 20a and 20b to the atmosphere. Here, the charging of the refrigerant is performed by opening the blocking valves 6 and 9 and introducing only the refrigerant sealed in the outdoor unit 40a into the connection pipes 7 and 8 and the indoor units 20a and 20b, and from the refrigerant cylinder to the connection pipe. In some cases, the connecting pipes 7 and 8 and the indoor units 20a and 20b are additionally filled in accordance with 7 and 8.

The operating time of the gas pump 50 is such that the pressure in the connection pipes 7 and 8 and the indoor units 20a and 20b is V _{h for} the internal volume of the outdoor unit 40a, V _{o is} the amount of oil in the outdoor unit 40a, When the sum of the internal volumes of the gas side connecting pipe 8 and the indoor units 20a and 20b is V _p and the internal / external volume ratio is β (= (V _h −V _o ) / V _p ), 94.7β + 95.5 [kPa (abs )], Preferably 65.7β + 66.5 [kPa (abs)] or less.

  At this time, even if the pressure in the connection pipes 7 and 8 and the indoor units 20a and 20b is determined by a pressure gauge, the content obtained from the pipe length of the connection pipes 7 and 8, the types of the indoor units 20a and 20b, and the number of connected units It may be determined based on the product and the discharge speed of the gas pump 50.

  Further, the maximum of the gas pump 50 based on the maximum pipe length of the connection pipes 7 and 8 connectable to the outdoor unit 40a, the type of the indoor units 20a and 20b, the maximum number of connected units, and the discharge speed of the gas pump 50. The operation time may be the operation time of the gas pump 50 in the outdoor unit 40a.

  The pressure in the connection pipes 7 and 8 and the indoor units 20a and 20b is reduced to less than 94.7β + 95.5 [kPa (abs)] by the gas pump 50, preferably 65.7β + 66.5 [kPa (abs)] or less. 7, 8 and the indoor units 20a and 20b are introduced with a refrigerant, and a cooling operation or a heating operation is performed.

  In the cooling operation, the high-temperature and high-pressure gas refrigerant compressed by the compressor 1 is discharged from the compressor 1, and the gas refrigerant flows into the heat source side heat exchanger 3 through the four-way valve 2 to exchange heat. Condensed liquid. The condensed and liquefied refrigerant passes through the fully expanded first expansion device 4, passes through the main flow pipe 31 and the dryer 32 in FIG. ) Is stored in the receiver 5, and the remainder is sent to the blocking valve 6 and the indoor units 20a and 20b. The sent liquid refrigerant flows into the second expansion device 21 and is depressurized to a low pressure to be in a low-pressure two-phase state, and exchanges heat with the use-side medium such as air in the use-side heat exchangers 22a and 22b to evaporate / Gasify. Thereafter, the gas refrigerant returns to the compressor 1 through the blocking valve 9, the four-way valve 2, and the accumulator 10.

  In the heating operation, the high-temperature and high-pressure gas refrigerant compressed by the compressor 1 is discharged from the compressor 1 and flows into the use-side heat exchanger 22 through the four-way valve 2 and the blocking valve 9, and the use-side medium such as air and the like. Heat exchange to condense. The condensed and liquefied refrigerant flows into the blocking valve 6, the receiver 5, the main flow pipe 31 and the dryer 32, is decompressed by the first expansion device 4, and is heated by a heat source medium such as air / water and heat in the heat source machine side heat exchanger 3. Replace and evaporate and gasify. The evaporated and gasified refrigerant returns to the compressor 1 through the four-way valve 2 and the accumulator 10.

During the above operation, moisture and non-condensable gas remaining in the connection pipes 7 and 8 and the indoor units 20a and 20b circulate in the refrigeration cycle together with the refrigerant.
FIG. 5 shows the experimental results of measuring the minimum compressor suction side pressure after starting the compressor 1 based on the amount of non-condensable gas remaining in the connection pipes 7 and 8 and the indoor units 20a and 20b. In the experiment, a 4 hp store inverter was used. The result of the cooling operation is indicated by a thin solid line. In the cooling operation, there was no event that the compressor 1 could not be started even if the amount of non-condensable gas increased. Therefore, the result of the cooling operation is set to the lowest pressure that can be stably started. In heating operation, when the amount of non-condensable gas exceeds a certain amount, the minimum suction pressure after start-up suddenly decreases, and when the amount of non-condensable gas is 1.15 [g / L], the suction pressure of the compressor 1 is zero. [KPa (abs)] and the compressor 1 could not be started.

  In order to start the compressor 1 stably, it is sufficient that the minimum suction pressure after starting the compressor 1 is not less than the minimum suction pressure that can be stably started. From FIG. 5, it is 0.8 [g / L] or less.

  Therefore, at a minimum, if the amount of non-condensable gas is less than 1.15 [g / L], the compressor 1 can be started, and in order to start stably, the amount of non-condensable gas is 0.8 [g / L] or less.

Here, the pressure p ₂ in the connecting pipes 7 and 8 and the indoor units 20a and 20b is defined as α [g / L] when the amount of non-condensable gas (air) in the connecting pipes 7 and 8 and the indoor units 20a and 20b is α. , Α and β, and p ₂ = (83.07α−0.80) β + 83.07α. Therefore, as the ultimate pressure in the connection pipes 7 and 8 and the indoor units 20a and 20b by the gas pump 50, in order to start the compressor 1 at a minimum, the non-condensable gas amount α <1.15 [g / L]. , P ₂ <94.7β + 95.5 [kPa (abs)], and in order to start stably, the amount of noncondensable gas α ≦ 0.8 [g / L], so p ₂ ≦ 65.7β + 66.5 [kPa] (abs)].

FIG. 6 shows a graph of the above results. Before exhausting the non-condensable gas in the connection pipes 7 and 8 and the indoor units 20a and 20b to the atmosphere by the gas pump 50, the connection points of the connection pipes 7 and 8 and the connection pipes 7 and 8 and the outdoor unit 40a and the indoor unit In order to confirm that there is no gas leakage at the connection points with 20a and 20b, the connection pipes 7 and 8 and the indoor units 20a and 20b are pressurized and filled with nitrogen, and a leak check is performed. Thereafter, connection pipe 7, 8 and the indoor unit 20a, since the nitrogen in 20b is opened to the atmospheric pressure, the pressure p ₂ in the immediately preceding connection pipe 7, 8 and the indoor units 20a, within 20b that run gas pump 50 is atmospheric pressure It is. Therefore, the internal / external volume ratio β = 0, which is the intersection of p ₂ = 65.7β + 66.5 [kPa (abs)] and the atmospheric pressure, which is the relationship between p ₂ and the internal / external volume ratio β when stable starting is possible. If it is 0.53 or more, it is possible to satisfy p ₂ ≦ 65.7β + 66.5 [kPa (abs)], which is a condition for stable operation, even if the gas pump 50 is not operated.

  The vacuum pump used when evacuating the inside of the connection pipes 7 and 8 and the indoor units 20a and 20b at the time of construction is a rotary type, but the gas pump 50 realizes a necessary ultimate pressure even if it is a diaphragm type, for example. It is possible.

  FIG. 4 shows a state in which a predetermined amount of air remains in the connection pipes 7 and 8 and the indoor units 20a and 20b. The result of extracting the phase refrigerant and analyzing the amount of non-condensable gas is shown. From this result, it can be seen that there is more non-condensable gas in the gas phase above the receiver 5 than the refrigerant circulating in the refrigeration cycle. It was. And by operating an air conditioner, non-condensable gas collects in the upper vapor phase part of the receiver 5, Therefore The adsorbent 33 for adsorb | sucking non-condensable gas was arrange | positioned in the vapor phase part of the receiver 5 upper part. Thereby, non-condensable gas can be adsorbed and removed efficiently.

  Further, moisture is adsorbed and removed by a dryer 32 disposed between the first expansion device 4 and the second expansion devices 21a and 21b, and the dryer 32 is disposed in a bypass portion that bypasses the main flow portion 31. The refrigerant flow rate flowing through the dryer 32 can be set to 10% or less as compared with the main flow portion. Therefore, it is possible to suppress wear of the dryer agent (desiccant) due to fluid force.

  Furthermore, for example, when the compressor 1 mounted on the outdoor unit 40a fails, the compressor 1 needs to be replaced. At the time of repair, after the refrigerant in the outdoor unit 40a, the connecting pipes 7 and 8, and the indoor units 20a and 20b is recovered by the refrigerant recovery device, the refrigeration cycle is opened to the atmosphere in order to repair the failed part. After repairing, seal the refrigeration cycle.

After that, the same work as at the time of construction will be carried out, but at the time of construction, it is only necessary to discharge the non-condensable gas in the connecting pipes 7 and 8 and the indoor units 20a and 20b to the atmosphere, but at the time of repairing the outdoor It is also necessary to discharge the non-condensable gas in the machine 40a. The pressure p ₁ of the outdoor unit 40a at the time of manufacture is lower than the pressures p ₂ in the connecting pipes 7 and 8 and the indoor units 20a and 20b that can stably start the compressor 1, and therefore the ultimate pressure of the gas pump 50 is the connecting pipe. 7 and 8 and the value determined from the internal volume of the indoor units 20a and 20b, the non-condensable gas is mixed in the refrigeration cycle for the pressure difference p ₂ -p ₁ in the outdoor unit 40a, and the compressor 1 is started. It may not be possible.

  For this reason, the ultimate pressure by the gas pump 50 is implemented until the internal / external volume ratio when all the internal volumes to be discharged by the gas pump 50 are the connection pipes 7 and 8 and the indoor units 20a and 20b, that is, a pressure that satisfies β = 0. There is a need to. At this time, in order to start the compressor 1 at a minimum, since the non-condensable gas amount α <1.15 [g / L], the ultimate pressure by the gas pump 50 <95.5 [kPa (abs)] and stable start Therefore, since the amount of non-condensable gas α ≦ 0.8 [g / L], it is desirable that the ultimate pressure by the gas pump 50 ≦ 66.5 [kPa (abs)].

  For the ultimate pressure of the gas pump 50 built in the outdoor unit 40a, a pump having the above value may be selected in consideration of repair or may be replaced with a pump having the above value during repair.

  In the present embodiment, an example of a refrigeration cycle apparatus will be described in which a non-condensable gas adsorbent 33a that adsorbs a non-condensable gas mixed in the refrigeration cycle is disposed at a location other than the gas phase portion above the receiver 5. FIG. 3 is an example of a cycle diagram in the second embodiment. The description of the components having the same functions as those shown in FIG. 1 already described with reference to FIG. 1 is omitted.

  As shown in FIG. 3, instead of the dryer 32 of FIG. 1, an adsorbent 34 that adsorbs moisture and non-condensable gas is disposed between the first expansion device 4 and the second expansion devices 21a and 21b. Although the efficiency of adsorbing and removing non-condensable gas is lower than that of FIG. 1, it is not necessary to enclose the non-condensable gas adsorbent 33 in the receiver 5. The development period can be shortened because there are fewer changes to the harmonic machine.

  Further, if non-condensable gas, in particular, adsorbent 33 for adsorbing oxygen and carbon dioxide is used, at least iron oxide and calcium oxide are used, iron oxide is oxygen, calcium oxide is moisture and carbon dioxide. Can be adsorbed and removed, and the efficiency is high. Since the non-condensable gas once adsorbed is firmly adsorbed in the adsorbent 33 by chemical adsorption, it is not released again during the refrigeration cycle.

DESCRIPTION OF SYMBOLS 1 Compressor 2 Four-way valve 3 Heat source machine side heat exchanger 4 1st expansion apparatus 5a, 5b, 5c Receiver 6, 9 Stop valve 7 Liquid side connection piping 8 Gas side connection piping 10 Accumulator 20a, 20b Indoor units 21a, 21b Second expansion device 22a, 22b Use side heat exchanger 30a Impurity recovery kit 31a Main pipe 32a, 32c Desiccant 33a, 33c Noncondensable gas adsorbent 34b Moisture and noncondensable gas adsorbent 35c, 36c Refrigerant inlet / outlet pipe 40a, 40b Outdoor unit 50 Gas pump 51a, 51b On-off valve 52a, 52b Gas pump connection piping 321c, 322c Bypass piping

Claims (7)

The compressor for compressing the refrigerant, the heat source device side heat exchanger, the first expansion device, the liquid side connection piping, the second expansion device, the use side heat exchanger, and the gas side connection piping are sequentially connected. In the refrigeration cycle equipment
Between the first expansion device and the second expansion device, an adsorbent that adsorbs at least oxygen and a dryer that adsorbs moisture in the non-condensable gas are disposed,
A gas pump is connected to at least one of the liquid side connection pipe or the gas side connection pipe,
The gas pump operates before the refrigerant is introduced into the liquid side connection pipe or the gas side connection pipe, thereby opening the non-condensable gas inside these connection pipes to the atmosphere. Cycle equipment. The refrigeration cycle apparatus according to claim 1,
After the refrigerant is introduced into the liquid side connection pipe and the gas side connection pipe, the refrigerant inside these connection pipes is recovered by the refrigerant recovery device, and further, after these connection pipes are opened to the atmosphere, These connecting pipes are sealed,
Thereafter, the gas pump is operated before the refrigerant is introduced into the connection pipes, thereby opening the non-condensable gas inside the connection pipes to the atmosphere. The refrigeration cycle apparatus according to claim 1,
A receiver for holding a refrigerant is provided in the liquid side connection pipe,
A refrigeration cycle apparatus, wherein the adsorbent is disposed inside the receiver. In the refrigeration cycle apparatus according to any one of claims 1 to 3,
A bypass pipe that bypasses the liquid side connection pipe is connected to the liquid side connection pipe,
The refrigeration cycle apparatus, wherein the dryer is disposed in the bypass pipe. In the refrigeration cycle apparatus according to any one of claims 1 to 3,
The internal volume of the heat source machine on which the compressor and the heat source machine side heat exchanger are mounted is V _h ,
Let V _o be the amount of oil in the heat source machine,
On the other hand, the sum of the internal volumes of the equipment on which the liquid side connection pipe, the gas side connection pipe and the use side heat exchanger are mounted is V _p , and the volume ratio is β (= (V _h −V _o ) / V _p ). Then,
The ultimate pressure of the gas pump is less than 94.7β + 95.5 [kPa (abs)]. In the refrigeration cycle apparatus according to any one of claims 1 to 3,
The internal volume of the heat source machine on which the compressor and the heat source machine side heat exchanger are mounted is V _h ,
Let V _o be the amount of oil in the heat source machine,
On the other hand, the sum of the internal volumes of the equipment on which the liquid side connection pipe, the gas side connection pipe and the use side heat exchanger are mounted is V _p , and the volume ratio is β (= (V _h −V _o ) / V _p ). Then,
The ultimate pressure of the gas pump is 65.7β + 66.5 [kPa (abs)] or less. In the refrigeration cycle apparatus according to any one of claims 1 to 3,
The internal volume of the heat source machine on which the compressor and the heat source machine side heat exchanger are mounted is V _h ,
Let V _o be the amount of oil in the heat source machine,
On the other hand, the sum of the internal volumes of the equipment on which the liquid side connection pipe, the gas side connection pipe and the use side heat exchanger are mounted is V _p , and the volume ratio is β (= (V _h −V _o ) / V _p ). Then,
When the volume ratio β is 0.53 or more, the gas pump is not operated.