JP2688979B2 - heat pump - Google Patents

Description

TECHNICAL FIELD The present invention relates to a heat pump, and particularly to a molecular formula C _k H _L Cl _m F _n (where k is an integer of 2 or more and l is an integer of 1 or more) as a working refrigerant. , M + n is a compound of an integer of 1 or more), and a refrigerant whose internal pressure in the evaporator is equal to or lower than atmospheric pressure (hereinafter, "main refrigerant"
That is) related to the heat pump.

Note that the heat pump here includes not only a heat pump in a narrow sense for producing a warm fluid but also a refrigerator for producing a cold fluid.

[Conventional technology]

BACKGROUND ART Conventionally, trichloromonofluoromethane (hereinafter referred to as “R-11”) is mainly used as a working refrigerant in a centrifugal compression type heat pump used for air conditioning of buildings.

However, the use of this type of CFCs has been internationally regulated in recent years because it destroys the ozone layer in the atmospheric stratosphere.

In other words, the ozone layer in the atmospheric stratosphere has a wavelength harmful to living organisms.
It has the function of absorbing light of 0 to 320 nm and preventing this light from reaching the ground, but chlorine (Cl) contained in this kind of Freon decomposes and destroys this ozone. For this reason,
Because harmful light reaches the ground surface, the use of this type of CFC has been restricted.

A specific example of this type of chlorofluorocarbon regulation is 1987
There is a protocol adopted at the Montreal Diplomatic Conference based on the Ozone Protection Treaty in September 1998. Where R
-11, R-113, R-12, R-114, R-115, etc. are subject to the regulation, and the production and consumption of them will be reduced stepwise.

For this reason, development of a heat pump using an alternative working refrigerant instead of R-11 mainly used for a centrifugal compression heat pump is urgently required.

A promising alternative working refrigerant is a compound of molecular formula C _k H _L C1 _m F _n (where k is an integer of 2 or more, is an integer of 1 or more, and m + n is an integer of 1 or more), and is vaporized. There is a refrigerant (main refrigerant) whose internal pressure is lower than atmospheric pressure. Since this refrigerant contains hydrogen atoms in its molecular formula, it is safe and non-polluting with almost no destruction of the ozone layer in the atmospheric stratosphere.

[Problems to be solved by the invention]

However, when actually considering the application of this refrigerant to a heat pump, it was found from the studies by the present inventors that the following problems would occur.

Table 1 is a table showing the results of thermal stability tests by a shield tube test performed by mixing C ₂ HCl ₂ F ₃ (hereinafter referred to as R-123) with turbine oil or air as a typical example of this refrigerant. is there.

As shown in the table, even if a mixture of R-123 and turbine oil was placed at 150 ° C for 5 days, R-123 was colorless and transparent, and the amount of hydrochloric acid generated was as small as 0.2 mg / 4 ml. Not only R-123 becomes brown when mixed with air,
The amount of hydrochloric acid generated is as much as 10.0 mg / 4 ml. In Table 1, when mixing turbine oil, C
u, Fu, and Al are used as catalysts, and when air is mixed, only Cu is used as a catalyst.

From the results of the above thermal stability test, R-123 has very excellent thermal stability when mixed with oil, but when air is mixed into it, it is decomposed and its thermal stability becomes extremely poor. .

The results are shown for R-123 as a representative example, but the present refrigerant containing hydrogen in other molecules and containing two or more carbon atoms also has similar properties.

Here, a compressor driven by an electric motor, a condenser, an evaporator, and a pressure reducing mechanism are provided, and these devices are connected by a path through which a working refrigerant passes to form a refrigerant circulation path, and an electric motor of the compressor. In the conventional heat pump that cools the refrigerant with the working refrigerant, the highest temperature portion in the heat pump with which the refrigerant contacts is the electric motor portion.

Therefore, when the air in the atmosphere leaks into the heat pump refrigerant path inside the electric motor and the main refrigerant is used as the working refrigerant, the main refrigerant is decomposed and the performance as the working refrigerant is obtained as in the test results. Is reduced. Therefore, there is a problem that a highly reliable heat pump cannot be provided.

In order to solve this problem, conventionally, when the heat pump is stopped, load water, heat source water or the like is caused to flow so that the internal pressure of the heat pump does not fall below the atmospheric pressure so that the temperature of the heat pump does not fall below a certain temperature. However, in this case, the power for driving the pump becomes very large, which is not economical.

The present invention has been made in view of the above points, and an object of the present invention is to provide an economical and highly reliable heat pump in which air in the atmosphere does not leak into the working refrigerant.

[Means for solving the problem]

In order to achieve the above object, the present invention provides a heat pump,
A compressor driven by an electric motor, a condenser, an evaporator, and a pressure reducing mechanism are provided, and these devices are connected by a refrigerant passage through which a working refrigerant passes to form a refrigerant circulation passage, and the electric motor of the compressor operates. A compound of molecular formula C _{k HL} Cl _m F _n (where k is an integer of 2 or more, l is an integer of 1 or more, and m + n is an integer of 1 or more) is used as the working refrigerant. In the heat pump in which the internal pressure of the evaporator is equal to or lower than the atmospheric pressure, the heat pump includes a bleed device for bleeding the non-condensable gas mixed in the refrigerant circulation path, and the bleed device is automatically operated before the operation of the heat pump compressor is started. It is configured with a means to be operated in a dynamic manner.

Further, the heat pump of the present invention is configured such that the extraction device can extract air from the electric motor portion.

Further, the heat pump of the present invention is configured such that the working refrigerant that cools the electric motor is the working refrigerant liquid that has been rectified so as not to contain air. The rectified working refrigerant liquid is the refrigerant liquid condensed in the condenser, and the liquid refrigerant passage extending from the condenser to the electric motor is composed of at least a descending passage and an ascending passage.

The extraction device used in the present invention compresses the working refrigerant gas in the condenser with the pressurizing device, then cools and condenses the working refrigerant gas with the cooling water or the outside air in the small condenser, and the working refrigerant liquid The structure is such that the air inside the small condenser is discharged to the outside while returning to the evaporator.

[Action]

By configuring the heat pump as described above, the extraction device attached to the heat pump can be operated before starting the heat pump operation.Therefore, the air mixed in the refrigerant in the refrigerant circulation path should be removed before the heat pump operation. The working refrigerant containing air does not circulate during operation of the heat pump.

Further, since the cooling of the electric motor is performed by the working refrigerant liquid that has been rectified so as not to contain air, there is no decomposition of the refrigerant in the electric motor portion having the highest temperature.

Further, since the present refrigerant containing hydrogen in the molecule is used as the working refrigerant, the ozone layer in the atmospheric stratosphere is hardly destroyed, and it is safe and pollution-free.

〔Example〕

Hereinafter, one embodiment of the present invention will be described in detail with reference to the drawings, but the present invention is not limited to these embodiments.

Example 1 FIG. 1 is a diagram showing a schematic configuration of a heat pump according to the present invention.

As shown in the figure, this heat pump includes a compressor 1 driven by an electric motor 24, condensed air 2, an evaporator 3, and a pressure reducing mechanism 4.
And each of these devices are connected by refrigerant paths 5, 6, 7, and 8 through which a working refrigerant passes to form a refrigerant circulation path. Here, the working refrigerant is composed of this refrigerant. The electric motor 24 is connected by the refrigerant paths 14 and 16 to form an electric motor cooling path. In the heat pump configured as described above, the working refrigerant gas compressed by the compressor 1 is cooled and condensed by the cooling fluid sent to the flow passage 9 in the condenser 2. Then, the condensed working refrigerant liquid passes through the refrigerant path 6 and is depressurized by the decompression mechanism 4 before reaching the evaporator 3.

In this evaporator 3, the working refrigerant liquid is heated and evaporated by the load fluid sent from the flow path 10, and returns to the compressor 1 again in the gas state through the refrigerant path 8 to form a heat pump cycle.

On the other hand, the load fluid flowing through the flow path 10 is cooled in the evaporator 3 and supplied to a load (not shown) such as cooling or freezing.

In the figure, the electric motor 24 that drives the compressor 1 is the condenser 2
Is cooled by the working refrigerant liquid sent by the pressurizing device 15 through the refrigerant passage 14 from. Then, this working refrigerant is heated and evaporated in the electric motor 24 and is sent to the condenser 2 again through the refrigerant path 16.

On the other hand, the cooling fluid flowing in the flow passage 9 heated by the condenser 2 is cooled by the cooler 11. Then, the cooled cooling fluid is circulated to the condenser 2 again by the pump 12.

In the present invention, in order to prevent the working refrigerant from being decomposed at the outlet of the electric motor or the compressor, the extraction device 30 for extracting the air leaking into the refrigerant path is provided.

In FIG. 1, the working refrigerant extracted from the condenser 2 is pressurized by a pressure device 18 through a pipe 17, is sent to a small condenser 19, and is sent to a pipe 22 as a cooling fluid (cooling water or outside air). Etc., the working refrigerant is cooled and condensed, and the decompression mechanism
Return to the evaporator 3 through 21 and the pipe 20.

On the other hand, air and the like contained in the working refrigerant sent to the small condenser 19 does not condense in the small condenser 19 and therefore gradually accumulates in the small condenser 19 and its internal pressure gradually increases. . Here, since the pressure valve 23 is configured to open when the force exceeds a certain level, the non-condensable refrigerant such as air in the small condenser 19 is exhausted from the pressure valve 23, and therefore the air in the heat pump is It is kept almost absent.

In the present embodiment, since the pressurizing device 18 is provided in the pipe 17, the bleeding device 30 before starting the heat pump operation.
Can drive Therefore, the air previously mixed in the working refrigerant can be extracted before starting the operation of the heat pump, and the air concentration can be kept low. This operation includes a method of automatically operating the bleed air recovery device for a certain period of time before starting the compressor during operation of the heat pump, and a method of operating the bleed air recovery device even when air is mixed by the pressure switch even when the air extraction is stopped.

Since the extraction device equipped in the conventional heat pump adopts a method of cooling the working refrigerant in the small condenser 19 by flowing the working refrigerant liquid in the condenser 2 into the pipe 22 in the small condenser 19, The pressure device 18 is not used. Therefore, conventionally, bleeding was possible only when the heat pump was operating.

As described above, with this configuration, the air concentration in the heat pump system is low, so no matter which part the working refrigerant for cooling the electric motor is sent from, there is no concern about the decomposition of the refrigerant.

Second Embodiment Next, another embodiment will be described with reference to FIG.

In this example, the operation before the heat pump operation of the extraction device 30 as described above is not necessary. That is, the place where the refrigerant is most easily decomposed, that is, the working medium that cools the electric motor 24 is configured to be the working medium that has been rectified so as not to contain air.

In FIG. 2, this rectified working refrigerant stream is the refrigerant stream condensed in the condenser 2 and is sent to the electric motor 24 through the refrigerant path 14 to cool the electric motor 24. On the other hand, this working refrigerant is heated and evaporated by the electric motor 24 and returns to the condenser 2 through the refrigerant path 16. Since air is not condensed in the condenser 2, the condensed refrigerant liquid does not contain air. Therefore, there is no concern that the refrigerant will be decomposed in the electric motor 24. However, when air may be contained in the condensed refrigerant, it is preferable to further provide a gas-liquid separator and remove the air component. Alternatively, it is desirable to provide a descending flow path and an ascending flow path 40 as the flow path 14 between the condenser and the electric motor so that air is not mixed in at the time of stop.

That is, during the stop, the liquid refrigerant in the condenser moves to the evaporator, and air easily enters from this flow, so that the liquid trap 41 is provided.

The above effects are the same in all cases where the electric motor 24 is cooled by the refrigerant liquid condensed so as not to contain air as described above.

Further, in FIG. 1, the bleeding device 30 is bleeding from the condenser 2, so that the non-condensable gas accumulated in the condenser 2 can be bleeded before and during the operation of the heat pump.
However, in order to completely extract the non-condensable gas before starting the heat pump operation, as shown in FIG.
It is preferable to extract air from Of course, it is more effective to extract air from the condenser 2 while the heat pump is operating.
17 may be branched into the condenser 2 and the electric motor 24, and controlled so as to effectively extract air from each.

The case where the extraction device 30 can be operated before starting the heat pump operation has been described above. However, as in the configuration of FIG. Of course, if the air in the electric motor 24 can be extracted effectively within the time, even if the extraction device 30 cannot be operated before the start of the heat pump operation, the same effect as that of the present invention can be obtained.

〔The invention's effect〕

As described in detail above, the heat pump according to the present invention has the following effects.

(1) Since the extraction device attached to the heat pump is automatically operated before the operation of the heat pump compressor is started, air or the like in the refrigerant circulation path can be extracted in advance when the heat pump is operated. It is possible to provide a highly reliable heat pump in which the working refrigerant is not decomposed in the high temperature part (electric motor or compressor pressurizing part).

(2) Since the electric motor is cooled by the working medium liquid rectified so as not to contain air, the working refrigerant is not decomposed in the electric motor section.

(3) Since this refrigerant is used as the working refrigerant, the ozone layer in the atmospheric stratosphere is hardly destroyed, and it is safe and pollution-free.

[Brief description of the drawings]

FIG. 1 is a diagram showing a schematic configuration of a heat pump according to the present invention, and FIGS. 2 and 3 are schematic configuration diagrams showing another embodiment of the present invention. 1 ... compressor, 2 ... condenser, 3 ... evaporator, 4 ... decompression mechanism, 24 ... motor, 5,6,7,8,14,16 ... refrigerant path, 1
3 ... Cooling fluid temperature control device, 13a ... Temperature sensor, 18 ...
… Pressurizer, 19 …… Small condenser, 30 …… Bleak device,

Claims (4)

(57) [Claims] 1. A compressor, a condenser, an evaporator, and a pressure reducing mechanism driven by an electric motor are provided, and these devices are connected by a refrigerant path through which a working refrigerant passes, and a refrigerant circulation path is formed.
The electric motor is cooled by a working refrigerant, and
As the working refrigerant, a molecular formula C _k H _L Cl _m F _n (where k is an integer of 2 or more, l is an integer of 1 or more, and m + n is an integer of 1 or more)
In the heat pump using the compound of, and the internal pressure of the evaporator is equal to or lower than the atmospheric pressure, the heat pump is equipped with an extraction device for extracting noncondensable gas mixed in the refrigerant circulation path,
The bleeding device is provided with means for automatically operating before the start of operation of the heat pump compressor. 2. The heat pump according to claim 1, wherein the extraction device is configured to extract air from the electric motor portion. 3. A compressor, a condenser, an evaporator, and a pressure reducing mechanism driven by an electric motor, which are connected by a refrigerant path through which a working refrigerant passes to form a refrigerant circulation path,
The electric motor is cooled by a working refrigerant, and the working refrigerant has a molecular formula of C _{k HL} Cl _m F _n (where k is an integer of 2 or more, l is an integer of 1 or more, and m + n is an integer of 1 or more). A heat pump using a compound and having an internal pressure of an evaporator equal to or lower than atmospheric pressure, wherein the working refrigerant for cooling the electric motor is a working refrigerant liquid rectified so as not to contain air. 4. The working refrigerant liquid rectified so as not to contain air is the liquid refrigerant condensed in the condenser, and the liquid refrigerant passage from the condenser to the electric motor is at least the descending passage. The heat pump according to claim 3, wherein the heat pump includes an ascending flow path.