JPS6150211B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a cooling air conditioner that can improve the effective energy ratio (E・E・R; ratio of refrigeration capacity to required power) without impairing dehumidification performance. Regarding.

In the current situation where energy saving is desired, it is extremely desirable to improve the E/E/R of an air conditioner and reduce its running cost.

It is well recognized that in order to improve E・E・R, it is theoretically possible to operate with a high evaporation temperature Te and a low condensation temperature Tc. Easy to understand.

By the way, it is said that the preferred cooling conditions in summer are when the outdoor temperature is 35°C and the indoor air condition is 27°C and relative humidity 50% (dew point temperature 15.5°C).In this case, the evaporation temperature in the refrigeration equipment is below 27℃,
Since the condensation temperature is required to be 35℃ or higher,
E・E・R has its own limits to what it can achieve.

In actual operation, it is necessary to maintain a temperature difference between the indoor and outdoor heat exchangers with the above temperature conditions, and further dehumidification is required regarding the evaporation temperature Te. Condensing temperature Tc
Generally, the values are ≒50°C and the evaporation temperature Te≒10°C, and E・E・R further decreases.

The movement of the indoor air on the psychrometric chart during the above operation is expressed as a line from A to B in Figure 3, and the intersection point △ of the extension of this line and the saturation line is Te = 10
℃, it is 12.5℃, but this is a temperature difference of this degree in an actual indoor heat exchanger.
This means that the outlet state point is on the line marked with 2.5℃.

In this way, there is a limit to the improvement of E・E・R in a single refrigerant system, and in view of the fact that no improvement can be expected, the present invention goes beyond such theoretical limits and further improves E・E・R. This invention was developed in an attempt to provide an air conditioner with a new system that can improve E/R.The specific details of the device of the present invention will be explained below with reference to the device examples and characteristic diagrams shown in the attached drawings. explain in detail.

In FIG. 2, the right half divided by the two-dot chain line is the outdoor unit 1, and the left half is the indoor unit 2. The outdoor unit 1 has two compressors 3A and 3B. Compression mechanism 3 and condenser 4
and an outdoor fan 9 are housed in the casing, while the indoor unit 2 includes an air cooling evaporator 5, a pressure reduction mechanism 6, a sensible heat recovery device 7, and indoor fans 10, 11. is housed inside the casing.

In the indoor unit 2, the evaporator 5 and the pressure reducing mechanism 6 each form two refrigerant systems, and the evaporator 5 is connected to the first evaporator 5A and the second evaporator 5B.
At the same time, the decompression mechanism 6 is connected to both evaporators 5 and 5.
It is formed from a first pressure reducer 6A and a second pressure reducer 6B corresponding to the pressure reducers A and 5B.

The first and second evaporators 5A and 5B are based on the indoor air flow inside the casing, and the first evaporator 5A and the second evaporator 5B are
is disposed on the windward side and the second evaporator 5B is disposed on the leeward side, and the indoor air flowing in from the suction port 12 is primarily cooled in the first evaporator 5A and then secondarily cooled in the second evaporator 5B to produce cold air. The air is then re-sent into the room through the air outlet 13.

The refrigeration circuit constructed between the two units 1 and 2 shares a condenser 4 as shown in FIG.
First compressor 3A → condenser 4 → first pressure reducer 6A → first evaporator 5A → refrigeration cycle of first compressor 3A and second compressor 3B → condenser 4 → second pressure reducer 6B
→Second evaporator 5B→Second compressor 3B Consists of two refrigerant systems in the refrigeration cycle, compressors 3A, 3
B, pressure reducer 6A, 6B and both evaporators 5A, 5B
By appropriately selecting the capacity of the first evaporator 5
A is the evaporation temperature Te ₁ higher than the dew point temperature of the indoor air
Further, the second evaporator 5B is formed so as to be able to operate at an evaporation temperature Te ₂ lower than the dew point temperature.

Note that, as in the above example, the device of the present invention has the first and second
Two compressors 3A, corresponding to the evaporators 5A, 5B,
In addition to providing 3B, in the case of a reciprocating multi-cylinder compressor, it may be one unit, and in the case of a rotary compressor, as long as it has a structure in which one unit has multiple cylinders, it may be used.

Further, the condenser 4 may also be of the shared circuit type as in the above example, but it is of course possible to use two condensers corresponding to the evaporators 5A and 5B to form mutually independent refrigeration cycles. .

The structure described above is for the refrigeration system, but the sensible heat recovery device 7 is provided to play an important role in improving E.E.R. When interposed in the air flow path in the interior, it is provided so as to cross the air flow at each position between the first evaporator 5A and the second evaporator 5B and on the downstream side of the second evaporator 5B.

By adopting the above-described arrangement, this sensible heat recovery device 7 transfers a part of the cold heat held by the secondary cooling air after passing through the second evaporator 5B to the first evaporator 5A.
It has the function of recovering heat to the primary cooling air after passing through it.

The operating mode of the apparatus having the above structure will be explained with reference to FIGS. 2 and 3.

When the compressors 3A, 3B and the fans 9, 10, 11 are energized and the sensible heat recovery device 7 is rotated to perform cooling operation, the indoor air A flowing in from the suction port 12 (see Fig. 3 below) is , first evaporator 5A (evaporation temperature Te ₁ ≒
The relative humidity increases as the temperature decreases due to primary cooling (20℃) and sensible heat change.

The air B in this state is further cooled by the cooling side heat exchange section 7b of the sensible heat recovery device 7 to become air in the state C, and the relative humidity becomes higher.

Next, the second evaporator 5B (evaporation temperature Te ₂ ≒10
The air is subjected to secondary cooling with dehumidification at a temperature (°C) to become the air in state D, which is heated through the heating side exchange part 7a of the sensible heat recovery device 7, and becomes air in state E, which is sent out from the air outlet 13 into the room. .

In addition, the sensible heat ratio connecting indoor air A and outlet air E
It is desirable to set SHF to about 0.75, for example, and this can be achieved by appropriately selecting the capacities of the first evaporator 5A, the second evaporator 5B, and the heat recovery device 7.

Here, the required power per unit refrigerant circulation amount in the first compressor 3A is W ₁ , the refrigeration capacity is Q ₁ , the refrigerant circulation amount is G ₁ , and the similar values in the second compression geometry 3B are W ₂ , Assuming Q ₂ and G ₂ , At that time, condensation temperature Tc = 40℃, first evaporation temperature Te ₁
= 20℃, second evaporation temperature Te ₂ = 10℃, the theoretical values for refrigerant R-22 are W ₁ = 3.3Kca/Kg, W ₂ = 4.9Kcal/Kg, Q ₁ = 40.4Kcal/Kg , Q ₂ = 39.6Kcal/Kg, is determined. G ₂ /G ₁ is calculated as follows.

The air weight flow rate passing through the first evaporator 5A is GW ₁ ,
Similarly, if GW ₂ is that of the second evaporator 5B, then Gw ₁・△i ₁ =G ₁・Q ₁ ………(B) Gw ₂・△i ₂ =G ₂・Q ₂ ………(C) However, please refer to Figure 4 for △i ₁ and △i ₂ , ∴G ₂ /G ₁ =Gw ₂ /Gw ₁ ×△i ₂ /△i ₁ ×Q
₁ /Q ₂ ...(D) In addition, Gw ₂ = Gw ₁ , and △i ₂ /△i ₁ = 1.1/1.45≒0.76 ∴G ₂ /G ₁ = 1×1.24×40 .4/39.6≒0.78
8 ∴EER=0.86×40.4+0.774×39.6/3
．． 3+0.774×4.9≒8.62.

On the other hand, in an air conditioner in which the evaporator is a single refrigerant system, when operated at an evaporation temperature of 10°C and a condensation temperature of 40°C, the EER is 7.0 as shown in Figure 1. In this case, it is clear that an improvement of 8.62-7.0/7.0×100≒23% can be achieved.

The reason why E・E・R can be improved in this way is as follows.

That is, the cooling capacity of the second evaporator 5B, which has a low evaporation temperature, is the same as that of the evaporator of a general air conditioner, which is a single refrigerant system, as shown by △i ₂ in the psychrometric diagram (Figure 3). It is possible to reduce it compared to that.

As shown in FIG. 4, the second invention further includes a mixed flow in the indoor unit 2 in which a part of the primary cooling air is blown out from the outlet 13 after passing through the sensible heat recovery device 7. Bypass path 8 for
is provided in the air flow path in the unit 2, but if the sensible heat recovery device 7 is of a rotating heat storage type structure as illustrated in FIG. A bypass path can be easily formed by providing an opening in the partition wall that partitions the cooling side flow path and the cooling side flow path.

In addition, in order to smoothly circulate air through the bypass path 8, the indoor air circulation system is equipped with two fans 1.
0 and 11, and the bypass passage 8 communicates with the suction port of the fan 11 facing the blowout port 13 at the rear stage.

Further, the bypass passage 8 is provided with an air volume adjusting device, such as a damper, for increasing or decreasing the bypass air volume.

Here, as mentioned above, the device shown in the fourth figure shows an example in which the sensible heat recovery device 7 has a rotating heat storage structure. This is an example in which the recovery device 7 is used, and the condenser 7
a is placed in the upper part, and the evaporator 7b is placed in the lower part, and both vessels 7a,
7b is cyclically connected through a liquid pipe and a gas pipe, and an appropriate amount of condensable gas refrigerant is sealed in this circulation path.

This example of the device is further characterized by being in the form of a compact package with an integrated structure in which the outdoor unit 1 and the indoor unit 2 are arranged at the bottom and the top, and is suitable as a practical device.

Note that, in addition to the above-mentioned two examples, a cross-flow stationary heat recovery device, a heat pipe type heat recovery device, etc. can also be applied to the sensible heat recovery device 7 according to the device of the present invention.

The operation mode of the device having the above structure is explained in the fourth section.
This will be explained below with reference to the figures and FIG.

When the compressors 3A, 3B and the fans 9, 10, 11 are energized and the sensible heat recovery device 7 is rotated to perform cooling operation, the indoor air A flowing in from the suction port 12 (see Fig. 6 below) is , first evaporator 5A (evaporation temperature Te ₁ ≒
The relative humidity increases as the temperature decreases just by changing the sensible heat caused by primary cooling (20℃).

A part of the air in this state is further cooled by the cooling-side heat exchange section 7b of the sensible heat recovery device 7 to become air in the state shown in C, and the relative humidity becomes higher.

Next, the second evaporator 5B (evaporation temperature Te ₂ ≒10
The air is subjected to secondary cooling with dehumidification at a temperature of 100° C.) to become the air in state (d), passes through the heating-side heat exchange section 7a of the sensible heat recovery device 7, is heated, and becomes the air in state (e).

This air is mixed with the rest of the air in the state B as it flows in from the bypass passage 8 to become the air in the state B, and is then sent out from the air outlet 13 into the room.

In addition, it is desirable that the sensible heat ratio SHF connecting indoor air A and the blown air in this state is set to, for example, about SHF = 0.75, so the bypass air volume can be adjusted by operating the air volume adjustment damper. There is.

When E·E·R in the above device is calculated in the same manner as in the calculation example for the device according to the first invention, the results are as follows (the specifications are the same as the above conditions except for the following).

That is, Gw ₂ /Gw ₁ is the line segment Loh/Gw 1 in FIG.
As a result of calculating from the line segment Roho on the psychrometric diagram,
It becomes 0.623.

Further, △i ₂ /△i ₁ =1.8/1.45≒1.24.

∴G ₂ /G ₁ = 0.623×1.24×40.4/39.6≒0
.788 ∴EER=0.86×40.4+0.788×39.6/3
．． 3+0.788×4.9≒8.60.

On the other hand, in an air conditioner in which the evaporator is a single refrigerant system, when operated at an evaporation temperature of 10°C and a condensation temperature of 40°C, the EER is 7.0 as shown in Figure 1. In the case of , it is clear that an improvement of 8.60-7.0/7.0×100≒23% can be achieved.

The reason why E・E・R can be improved in this way is as follows. In other words, the second compressor 3B operates at a low evaporation temperature Te ₂ with poor EER.
This is due to the fact that by using the sensible heat recovery device 7 and the bypass path 8, it has become possible to reduce the refrigeration processing capacity of the refrigerating system compared to that of a conventional single refrigerant system.

Note that when the bypass path 8 in the above example is not used, the amount of indoor air passing through the second evaporator 5B increases compared to the above example, and the refrigeration processing capacity of the second compressor 3B increases, but the blown air condition does not change as described above. Similarly to the example, the fourth
As shown in the figure, if the state shown in _FIG .

The above is a theoretical effect on EER, but in reality, as is clear from FIG. Evaporation temperature Te ₂ of the second evaporator 5B when cooling and dehumidifying from state C to state D
This means that it can be higher than in the case of a conventional single refrigerant system, which leads to an improvement in E・E・R.

Furthermore, the suction gas pressure in the first compressor 3A becomes higher than in the case of a normal single refrigerant system, and the specific volume of refrigerant gas decreases, so the compression function increases when comparing the same capacity, Since the compression ratio is also reduced, the values of gas leakage, backflow, mechanical friction loss, etc. inside the compressor are all reduced, which has the effect of improving efficiency, and the above-mentioned rate of improvement in EER further increases.

Next, to explain Fig. 7 and Fig. 8,
This is a modification of the device of the above example, in which the second evaporator 5B is further divided into an upstream evaporator 5B- ₁ and a downstream evaporator 5B- ₂ , and the evaporation temperature of the former is 12°C. The temperature is set higher than the latter 10℃, and lower than the dew point temperature of indoor air.

With such a structure, when the same calculation as in the above example was performed, E・E・R≒8.62, which shows that the EER is improved, albeit slightly.

In addition, as an operating method, when the indoor humidity is low and there is no need to dehumidify, the second evaporator 5B
If the evaporator 5A is stopped and only the first evaporator 5A is operated, the EER can be further improved. In addition, when only dehumidification is required, only the second evaporator 5B is operated and the first evaporator 5B is operated.
Of course, EER will improve even if A is stopped.

As clarified by the above description, the first invention includes an outdoor unit 1 having a compression mechanism 3 and a condenser 4, a first evaporator 5A, a second evaporator 5B, and a refrigerator. It consists of an indoor unit 2 having a heat recovery device 7, and the first evaporator 5A is disposed on the upstream side and the second evaporator 5B is disposed on the downstream side with respect to the flow direction of the indoor air flow in the indoor unit 2. Then, the first evaporator 5A is replaced with the second evaporator 5B.
A refrigeration circuit is formed between the two units 1 and 2, each operating at an evaporation temperature higher than that of placed on the side, the second
It is characterized by a configuration in which a part of the cold heat held by the secondary cooling air after passing through the evaporator 5B can be recovered into the primary cooling air after passing through the first evaporator 5A. Conventional so-called single-system evaporator type air conditioners, which maintain a large temperature difference between indoor air temperature and evaporation temperature and perform cooling operation with one evaporator in order to maintain cooling capacity, have reached their limits. This is an economical air conditioner that can save energy by further improving the E・E・R.

Furthermore, according to the embodiments, latent heat changes can be utilized in addition to sensible heat changes, further improving efficiency.

Next, the second invention reduces the amount of indoor air passing through the second evaporator by providing a bypass path,
Since the refrigeration processing capacity of the second compressor, which has a low evaporation temperature and poor E・E・R, can be reduced, the E・E・R is low.
It is possible to improve E/R.

Furthermore, if the second invention is as described in the embodiment section,
E・E・R can be improved while maintaining comfortable air conditioning conditions.

[Brief explanation of the drawing]

Figure 1 is a diagram showing the relationship between the theoretical effective energy ratio of the compressor and the evaporation temperature in a refrigeration system.
The figure is a refrigeration circuit diagram of an example of the device according to the first invention,
The figure is also an psychrometric diagram to explain the driving characteristics.
FIG. 4 is a refrigeration circuit diagram of an example of a device according to the second invention;
FIG. 5 is a front view schematically showing the specific structure of the device of the present invention, FIG. 6 is an psychrometric diagram for explaining the operating characteristics of the device of the present invention shown in FIG. 4, and FIGS. 7 and 8. 1 is a schematic structural diagram and an psychrometric diagram according to an example of the device of the present invention. 1...Outdoor unit, 2...Indoor unit,
3... Compression mechanism, 3A... First compressor, 3B...
2nd compressor, 4... Condenser, 5... Evaporator, 5A
...First evaporator, 5B...Second evaporator, 6A, 6
B... Pressure reducer, 7... Sensible heat recovery device, 8... Bypass path, 9... Outdoor side fan, 10, 11... Indoor side fan, 12... Suction port, 13... Air outlet.

Claims (1)

[Scope of Claims] 1 Consists of an outdoor unit 1 having a compression mechanism 3 and a condenser 4, and an indoor unit 2 having a first evaporator 5A, a second evaporator 5B, and a sensible heat recovery device 7. The first evaporator 5A is disposed on the upstream side and the second evaporator 5B is disposed on the downstream side with respect to the flow direction of the indoor air flow in the inner unit 2. Refrigeration circuits each operating at an evaporation temperature higher than the evaporation temperature are formed between the two units 1 and 2, while the sensible heat recovery device 7 has a heat exchanger located upstream and downstream of the second evaporator 5B. A part of the cold heat held by the secondary cooling air after passing through the second evaporator 5B can be recovered to the primary cooling air after passing through the first evaporator 5A. An air conditioner featuring: 2. The air conditioner according to claim 1, wherein the first evaporator 5A is operated at an evaporation temperature higher than the dew point temperature of indoor air, and the second evaporator 5B is operated at an evaporation temperature lower than the dew point temperature. . 3 Consists of an outdoor unit 1 having a compression mechanism 3 and a condenser 4, and an indoor unit 2 having a first evaporator 5A, a second evaporator 5B, and a sensible heat recovery device 7, and indoor air flow in the indoor unit 2. The first evaporator 5A is located on the upstream side with respect to the flow direction of
The second evaporators 5B are arranged on the downstream side, and the first evaporator 5A is operated at an evaporation temperature higher than the dew point temperature of indoor air, and the second evaporator 5B is operated at an evaporation temperature lower than the dew point temperature. A refrigeration circuit is formed between the two units 1 and 2, while the sensible heat recovery device 7
In this method, heat exchangers are arranged upstream and downstream of the second evaporator 5B, and a part of the cold heat held by the secondary cooling air after passing through the second evaporator 5B is transferred to the first evaporator 5B.
Heat can be recovered to the primary cooling air after passing through the evaporator 5A, and a part of the primary cooling air after passing through the first evaporator 5A is converted into the blowout cooling air after passing through the sensible heat recovery device 7. An air conditioner characterized in that a bypass passage 8 for mixed flow is provided in an indoor unit 2. 4. The air conditioner according to claim 3, wherein the bypass passage 8 has a bypass air volume adjusting device interposed therebetween in order to maintain a constant sensible heat ratio between the intake air and the blown air.