JPS6327621B2 - - Google Patents

Description

[Detailed description of the invention] The present invention is capable of maintaining a high effective energy ratio (E・E・R, ratio of refrigeration capacity to required power) while increasing dehumidification capacity and ensuring a low sensible heat ratio. Regarding possible air conditioners.

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.

By the way, the air conditioning condition in summer is when the outdoor temperature is 35℃, and the indoor air condition is 27℃ relative temperature 50%.
(dew point temperature of 15.5℃). In this case, the evaporation temperature in the refrigeration equipment is required to be 27℃ or less, and the condensation temperature is required to be 35℃ or higher. has its own limits.

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
It is common to take values of ≒50°C and evaporation temperature Te≒10°C, and E・E・R further decreases.

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.・While aiming to improve R,
This invention was developed in an attempt to provide an air conditioner with a new system that can ensure dehumidification ability, and the specific contents of the device of the present invention will be explained in detail below with reference to device examples and characteristic diagrams shown in the attached drawings. do.

In FIG. 1, 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 includes two compressors _3A and 3. A compression mechanism 3 consisting of _B and a condenser 4
and an outdoor fan 7 are housed in the casing, while an air cooling evaporator 5, a pressure reducing mechanism 6, and an indoor fan 8 are housed in the casing of the indoor unit 2.

In the indoor unit 2, the evaporator 5 and the pressure reducing mechanism 6 each form two refrigerant systems, and the evaporator 5 is divided into a first evaporator _5A and a second evaporator _5B . The pressure reducing mechanism 6 is connected to both evaporators _5A ,
5 _B , the first pressure reducer 6 _A and the second pressure reducer 6 _B
It is formed from.

The first and second evaporators 5 _A and 5 _B are arranged such that the first evaporator 5 _A is disposed on the upstream side and the second evaporator 5 _B is disposed on the downstream side, with respect to the indoor air flow in the casing.
The indoor air flowing in from the suction port 9 is transferred to the first evaporator _5A.
After primary cooling, the second evaporator 5 _B performs secondary cooling to produce cold air, which is then re-sent into the room through the outlet 10.

The refrigeration circuit constructed between the two units 1 and 2 shares a condenser 4 as shown in FIG.
1st compressor 3 _A → condenser 4 → 1st pressure reducer 6 _A → 1st
Evaporator 5 _A → first refrigeration cycle of first compressor 3 _A and second compressor 3 _B → condenser 4 → second pressure reducer 6 _B →
It consists of two refrigerant systems in the second refrigeration cycle: second evaporator 5 _B → second compressor 3 _B , compressors 3 _A , 3 _B ,
By appropriately selecting the capacities of the pressure reducers 6 _A , 6 _B and both evaporators 5 _A , 5 _B , the first evaporator 5 A can be operated at an evaporation temperature Te ₁ higher than the dew point temperature of the indoor air, and the first evaporator 5 _A can be The two evaporators _5B are formed so that they can each be operated at an evaporation temperature _Te2 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 and _3B correspond to the evaporators _5A and _5B .
In addition, in the case of a Sumifuku multi-cylinder compressor, there may be one unit, and in the case of a rotary compressor, there may be one unit.
As long as it has a structure with multiple cylinders, any structure is acceptable.

Furthermore, the condenser 4 may also be of the shared circuit type as in the above example, but of course two condensers may be used corresponding to the evaporators 5 _A and 5 _B to form mutually independent refrigeration cycles. No problem.

Next, to explain the operating mode of the device with the above structure, by energizing both the first compressors _3A and _3B , the indoor air A flowing in from the suction port 9 is transferred to the first evaporator _5A. The temperature decreases due to only sensible heat changes, and the relative humidity increases.

This air is further cooled secondary with dehumidification in the second evaporator _5B , and after changing its latent heat and sensible heat to become low-temperature, dehumidified air, it is sent back into the room from the outlet 10. .

Here, the required power per unit refrigerant circulation amount in the first compressor _3A is W ₁ , the refrigeration capacity is Q ₁ , and the refrigerant circulation amount is G ₁ , and similar values in the second compression 3 _B are W ₂ , Assuming Q ₂ and G ₂ , compressor EER=0.86×G ₁ Q ₁ +G 2 Q 2 /G ₁ W _{1 +} G ₂ W ₂ =0.86× _{Q 1 +} G ₂ /G ₁ Q ₂ /W ₁ +G ₂ /G ₁ W ₂ …
...(A) At that time, condensation temperature Tc = 40℃, first evaporation temperature
Assuming Te ₁ = 20°C and second evaporation temperature Te ₂ = 9°C,
The theoretical values for refrigerant R-22 are determined as follows: W ₁ = 3.3Kcal/Kg, W ₂ 5.0Kcal/Kg, Q ₁ = 40.4Kcal/Kg, Q ₂ = 39.6Kcal/Kg. Note that G ₂ /G ₁ is calculated as follows.

If the air weight flow rate passing through the first evaporator 5 _A is GW ₁ and that of the second evaporator 5 _B is GW ₂ , then GW ₁・△i ₁ = G ₁ Q ₁ ...(B) GW ₂・△ i ₂ = G ₂ Q ₂ ...(C) However, please refer to Figure 2 for △i ₁ and △i ₂ , ∴G ₂ /G ₁ =GW ₂ /GW ₁ ×△i ₂ /△i ₁ ×Q ₁ /Q ₂ ...(D) Here, since GW ₂ /GW ₁ = 1, G ₂ /G ₁ = 1 × 11.8 − 9.3 / 13.25 − 11.8 × 40.4 / 39.6 = 2.5 / 1.45 × 40.4 / 39.6≒1.76 ∴EER＝0.86×40.4＋1.76×39.6／3.3＋1.76×5.0≒7
It becomes .83.

On the other hand, in an air conditioner where the evaporator is a single refrigerant system, the evaporation temperature is 10℃ and the condensation temperature is
Operating at 40°C gives an EER of 7.0, therefore:
It is clear that in the case of the device of the present invention, an improvement of 7.83-7.0/7×100≒11.9% can be achieved.

This is due to _the fact that the refrigerating capacity of the second compressor _3B , which operates at a low evaporation temperature Te2 with poor EER, is made relatively small compared to the conventional single refrigerant system.

The above is a theoretical effect on EER, but in reality, the suction gas pressure in the first compressor _3A becomes higher than in the case of a normal single system, and the specific volume of refrigerant gas decreases, so the same capacity When compared, the compression function increases and the compression ratio decreases, which reduces the values of gas leakage, backflow, mechanical friction loss, etc. inside the compressor, and improves efficiency. The rate of EER improvement mentioned above will further increase.

Therefore, the device of the present invention includes a first compressor _3A to which the first evaporator _5A having a higher evaporation temperature is connected;
The capacity ratio (cylinder volume, cooling capacity ratio under the same operating conditions) with the second compressor 3 _B to which the second evaporator 5 _B is connected is determined as follows: Capacity of the first compressor 3 _A ≦ Second compressor 3 The capacity relationship of _B is maintained.

By providing such a capacity relationship, the following characteristics are exhibited.

In the air conditioner shown in the first figure, the first evaporator 5
The _evaporation temperature Te ₁ of the second evaporator 5 B is raised to mainly perform sensible heat cooling, while the evaporation temperature Te ₂ of the second evaporator 5 _B is lowered to perform dehumidification cooling, thereby dehumidifying the whole. High E・E・ without sacrificing performance
Here, if the capacity of the first compressor 3 _A is relatively large, the amount of heat exchange in the first evaporator 5 _A is proportional to the difference between the indoor air temperature and the evaporation temperature Te ₁ . Therefore, this evaporation temperature Te ₁ inevitably becomes low and becomes Te′ ₁ in Fig. 3, and the second compressor 3
If the capacity of _B is relatively small, the evaporation temperature Te ₂ becomes balanced in a high temperature range Te' ₂ and as a result, the effect of improving E・E・R is suppressed.

Furthermore, regarding the sensible heat ratio, which represents the dehumidification ability,
In particular, as the evaporation temperature Te ₂ becomes as high as Te' ₂ , the dehumidification performance decreases.

These problems can be solved by reducing the capacity of the first compressor _3A relative to the second compressor _3B , thereby reducing the evaporation temperature Te ₁ and reducing the evaporation temperature.
Suppressing the rise in Te ₂ and stabilizing at high E・E・R,
Dehumidification performance can be ensured.

This is a characteristic line drawn on a chart with the horizontal axis representing the ratio of the first compressor 3 _A and the second compressor 3 _B and the vertical axis representing E・E・R and the sensible heat ratio SHF (see Figure 4). ) is further clarified by:

Such characteristics can be achieved by specifying the capacity ratio of the compressor to the above-mentioned conditions, but as described below, the present invention also provides the following features: By appropriately selecting the heat exchange amount), the above-mentioned effects can be further exhibited.

In this case, the relationship is such that the capacity of the first evaporator _5A ≧the capacity of the second evaporator _5B , and by doing so, the evaporation temperature _Te1 will be higher and the evaporation temperature _Te2 will be higher. Since the equilibrium will be even lower, the dehumidification performance will tend to improve, but the evaporation temperature
The main factor that determines Te ₁ and Te ₂ is the compressor.
The capacity ratio of the heat exchanger (evaporator) will also be affected considerably.

In addition, in FIG. 4, when the capacity of the second compressor 3 _B is increased, the evaporation temperature Te ₂ of the second evaporator 5 _B becomes higher, and as a result, the sensible heat ratio becomes higher.
R may become apparently high. (In Figure 3, the capacity ratio is close to 1).

However, since the dehumidification performance is impaired accordingly, if the capacity of the second evaporator _5B is lowered relative to the first evaporator _5A in order to obtain the same sensible heat ratio, E. The E.R. decreases as shown by the solid line, and thus a high E.E.R. can be ensured without impairing the dehumidification performance.

Figure 5 shows the changes in E・E・R and sensible heat ratio (SHF) with respect to the evaporator capacity ratio under the constant condition of compressor capacity ratio 1st compressor/2nd compressor = 0.55. The results show that in the range of first evaporator 5 _A /second evaporator 5 _B = 1 to 2, the dehumidification capacity is large and E·E·R becomes large.

As is clear from the above description, the present invention includes a first refrigeration circuit including a first evaporator _5A disposed upstream of the flow of air introduced from the suction port 9.
By operating the second refrigeration circuit including the second evaporator _5B located on the downstream side at a higher evaporation temperature, and by making the compressor of the first refrigeration circuit the same or smaller in size. Therefore, it is possible to obtain high E・E・R while ensuring a low sensible heat ratio,
Low running cost operation can be guaranteed.

Furthermore, it does not impair dehumidification performance and is highly suitable for use in all seasons.

Furthermore, the present invention reduces the capacity of the first evaporator 5 _A to the second evaporator 5 A.
By adding a configuration that increases the same amount or larger size to the evaporator _5B , the above-mentioned effects can be more stably secured, and each evaporator _5A and _5B can be used without waste, The low cost effect can be further enhanced.

[Brief explanation of the drawing]

FIG. 1 is a device circuit diagram according to an example of the device of the present invention, and FIG.
3 and 3 are psychrometric diagrams for explaining the characteristics of the device of the present invention, and FIG. 4 is the compressor capacity ratio.
E・E・R, sensible heat ratio diagram. FIG. 5 is also an evaporator capacity ratio - E・E・R, sensible heat ratio diagram. 3 _A ...First compressor, 3 _B ...Second compressor, 5 _A
...Second evaporator, 5 _B ...Second evaporator.

Claims (1)

[Scope of Claims] 1. The first evaporator 5 _A is disposed on the upstream side and the second evaporator 5 _B is disposed on the downstream side with respect to the air flow from the suction port 9 to the blowout port 10. _5A and a first refrigeration circuit including a first compressor _3A , and a second refrigeration circuit including a second evaporator _5B and a second compressor _3B , the first refrigeration circuit is connected to a second refrigeration circuit. While operating at a higher evaporation temperature than the circuit, the capacity of the first compressor _3A is made equal to or smaller than the capacity of the second compressor _3B , and the first evaporator _{5A is}
An air conditioner characterized in that the capacity of the second evaporator _5B is the same as or larger than the capacity of the second evaporator 5B. 2. The air conditioner according to claim 1, wherein the evaporation temperature of the first refrigeration circuit is higher than the dew point temperature of indoor air, and the evaporation temperature of the second refrigeration circuit is lower than the dew point temperature.