JPH04251147A - Air conditioner - Google Patents

Abstract

PURPOSE:To provide a multi-room type air conditioner capable of preventing any disadvantages such as frosting at an indoor device and a blowing of frost or the like independent of the humidity in a room and further capable of preforming an operation of each of the rooms with a wide capability control range. CONSTITUTION:An indoor device 28 is provided with humidity sensors 29a and 29b. During a cooling operation, the lowest opening of a valve 25 for controlling a flow rate of the indoor device 28 is changed according to detected values of the humidity sensors 29a and 29b, a superheat upper limit value of each of the indoor devices 28 is varied with the detected value of each of the humidity sensors and then the opening of a valve 25 for adjusting the flow rate is controlled in such a way that value does not exceed this upper limit value.

Description

[Detailed description of the invention]

[Object of the invention]

0002

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a so-called multi-type air conditioner having a plurality of indoor units.

0003

2. Description of the Related Art FIGS. 7 and 8 show one conventional example of this type of air conditioner.

That is, as shown in FIG. 7, the compressor 1,
A closed refrigeration cycle is constructed by sequentially connecting a four-way valve 2, an outdoor heat exchanger 3, an expansion valve 4, a electronic flow control valve (PMV) 5, an indoor heat exchanger 6, and a solenoid valve 7. . Here, the electronic flow rate adjustment valves 5 (5a, 5b), the indoor heat exchangers 6 (6a, 6b), and the solenoid valves 7 (7a, 7b) are arranged in multiple sets corresponding to the number of rooms that require air conditioning. They are provided as indoor units 8a and 8b, thereby configuring a multi-type air conditioner.

[0005] In such an air conditioner, during cooling operation, the capacity of each room is changed in accordance with the capacity required from the room. That is, each indoor unit 8
For example, as shown in the table of FIG. 2, the opening degrees of the electronic flow rate regulating valves 5a and 5b corresponding to the valves 5a and 8b are changed to various opening degrees (from 0 pulses to 120 pulses), and ，
Capacity control is performed by changing the amount of super heat of 6b.

In this case, in an indoor unit (for example, 8a) in a room where the capacity requirement is very small, the evaporation of the refrigerant is completed in the middle or near the inlet of the indoor heat exchanger 6a and becomes superheated gas. The amount of superheating (superheat) in the inner heat exchanger 6a becomes extremely large.

However, in a situation where the capacity requirement is very small but the indoor humidity is very high, when the amount of super heat increases in the indoor heat exchanger 6a as described above, the indoor heat exchanger 6a The indoor air passing through the indoor unit 8a is cooled, causing the air to reach the dew point, which results in the indoor air passing through the indoor unit 8a
However, problems such as condensation may occur.

Furthermore, when there is a mixture of air that reaches its dew point through cooling and air that simply passes through the indoor heat exchanger 6a without being cooled much, the mixture of these two types of air causes the air that has reached its dew point to become foggy. The phenomenon of blowing out may occur.

Next, another conventional example will be explained with reference to FIGS. 9 and 10.

In the example shown in FIG. 9, the variable capacity compressor 1,
An outdoor heat exchanger 3 as a condenser, one expansion valve 4 as a refrigerant throttling mechanism, and a plurality of parallelly arranged indoor heat exchangers 6a and 6b as evaporators are sequentially connected and closed. A refrigeration cycle is configured. A control circuit section 9 for varying capacity is connected to the compressor 1, and an expansion valve heat sensing section 10 and an expansion valve pressure sensing section 11 are connected to the expansion valve 4.

In this example, one refrigerant throttling mechanism is used to divide the refrigerant into each chamber and control the refrigerant gas sucked into the compressor 1 to have a constant degree of superheat. Further, the cooling capacity control is performed by calculating a capacity request signal from a controller (not shown) of each indoor unit, and increasing or decreasing the capacity of the compressor by controlling the rotation speed, for example.

However, in such a configuration, although it is possible to control the capacity of the entire apparatus, it is inconvenient that the capacity cannot be controlled individually for each indoor unit.

Therefore, as shown in FIG. 10, a plurality of expansion valves 4 are provided so as to correspond to each indoor unit. Based on the detected values of the evaporation temperature sensor 12 and the compressor suction refrigerant temperature sensor 13,
A system has been proposed in which the opening degree of each expansion valve 4 is adjusted so as to keep the degree of superheat constant. Note that 14 is a capillary tube. By the way, if the capacity requests in each room are unbalanced, for example, one side requests a large capacity and the other one requests a small capacity, the opening degree of the expansion valve 4 will be reduced in the indoor unit with the smaller required capacity. Become. However, the evaporation temperature is determined by controlling the refrigerant that has passed through a plurality of indoor units and joined to maintain a constant degree of superheating, so there is less refrigerant on the side where the expansion valve 4 is narrowed down and it evaporates easily, so the indoor heat is At the outlets of the exchangers 6a and 6b, as in the first conventional example, the degree of superheat increases and phenomena such as dew formation occur on the indoor unit. Therefore, the expansion valve 4 cannot be narrowed down to a large extent, resulting in a problem that the range of capacity variation is limited to a certain extent.

[0014]

In the configurations of the above-mentioned conventional examples, when the indoor humidity is extremely high, problems such as dew buildup and fog blowing occur in indoor units that are highly overheated. Additionally, there is a problem in that the range of capability variability is subject to certain limitations.

The present invention was made in view of the above circumstances, and its first purpose is to provide a multifunction device that can prevent problems such as dew buildup and mist from blowing out of indoor units, regardless of indoor humidity conditions. Our objective is to provide type of air conditioner.

A second object is to provide a multi-type air conditioner that is capable of controlling the capacity of each room over a wide range of operation while suppressing dew formation and the like.

[Configuration of the invention]

[0018]

[Means for Solving the Problems] The invention according to claim 1 includes a plurality of indoor units arranged in parallel in a refrigeration cycle, and a valve for controlling the refrigerant flow rate for each of these indoor units,
In a multi-type heat pump air conditioner that determines the opening degree of each flow rate control valve based on the required capacity from each indoor unit, and controls the refrigerant flow rate to each indoor unit to perform variable capacity control. A humidity sensor is provided in each of the indoor units, and the minimum opening degree of each of the flow rate control valves can be changed during cooling operation according to the detected value of the humidity sensor.

[0019] According to the second aspect of the invention, the refrigeration cycle is provided with a plurality of indoor units arranged in parallel and a valve for controlling the refrigerant flow rate for each of these indoor units, based on the required capacity from each of the indoor units. A multi-type multi-type device that sets the compressor function power by setting the compression function, and also determines the opening ratio of the valves for controlling the flow rate, and controls the opening degree of the valves for controlling the flow rate so that the amount of superheat in all units is constant. In the air conditioner, a humidity sensor is provided for each indoor unit, and the superheat upper limit of each indoor unit is set according to the detected value of the humidity sensor of each indoor unit and the detected value of the amount of superheat of the refrigerant during cooling operation. By changing the value, it is possible to control the opening degrees of the respective flow rate control valves so as not to exceed the upper limit value.

Specifically, this is a multi-air conditioner with multiple indoor units, each indoor unit is equipped with an electric expansion valve that controls the refrigerant flow rate, and the compression function power is set in response to the capacity request signal from each indoor unit. In a multi-air conditioner that determines the opening ratio of each electric expansion valve and controls the opening of the electric expansion valve so that the overall amount of superheat remains constant, a humidity sensor is installed in each indoor unit, and a humidity sensor is installed in each indoor unit. Detects the amount of superheat of refrigerant for each unit,
The superheat upper limit value of each indoor unit is changed according to the detected value of the humidity sensor during cooling operation, and the opening degree of each electric expansion valve is controlled so as not to exceed this upper limit value.

[0021]

According to the invention of claim 1, the indoor unit is provided with a humidity sensor, and during cooling operation, the minimum opening degree of the valve for controlling the flow rate of the indoor unit is changed according to the detected value of the humidity sensor. Therefore, for example, even if the capacity request from one indoor unit is a minimum value that would increase the amount of superheat, if the humidity is above a certain level, the minimum opening degree of the valve for adjusting the flow rate will be reduced. By doing so, the amount of superheat can be reduced. Therefore, phenomena such as dew forming on the indoor unit or dew blowing out from the indoor unit can be prevented.

[0022] Note that when the humidity is below a certain level, the minimum valve opening degree for flow rate adjustment becomes large, but in this case, since the humidity is low, dew condensation does not occur, and therefore the original temperature requirements can be adequately met. be able to.

[0023] Therefore, under any humidity conditions, it is possible to prevent dew from forming on the indoor unit and from blowing out from the indoor unit.

Further, according to the invention of claim 2, a humidity sensor is provided for each indoor unit, and the amount of superheat of the refrigerant is detected for each indoor unit, and the amount of superheat in each indoor unit is determined according to the detected value of the humidity sensor during cooling operation. By changing the super heat upper limit value of the unit and controlling the opening degree of the flow rate adjustment valve so as not to exceed this upper limit value, even when the required capacity of each room becomes unbalanced, it is possible to Do not over-tighten the valve. Therefore, it is possible to reliably prevent phenomena such as superheat becoming large and causing dew on the indoor unit.

In other words, a humidity sensor is installed in each room, and the upper limit of the degree of superheating of the refrigerant in each room is made variable depending on the humidity situation, so the valve can be throttled down to the minimum while suppressing dew formation. As a system, it is possible to operate with a wide range of capacity control for each room.

[0026]

Embodiments Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIGS. 1 and 2 show an embodiment of the invention according to claim 1.

As shown in FIG. 1, a compressor 21, a four-way valve 2
2. Outdoor heat exchanger 23, expansion valve 24, electronic flow control valve (PMV) 25, indoor heat exchanger 26, and solenoid valve 27
are connected in sequence to form one closed refrigeration cycle. Here, the electronic flow rate adjustment valve 25 (25a, 25
b), the indoor heat exchanger 26 (26a, 26b) and the solenoid valve 27 (27a, 27b) are connected to two sets of indoor units 28a, 28a, 27b, corresponding to the number of rooms that require air conditioning, for example, 2 rooms;
28b, thereby configuring a multi-type air conditioner.

Each indoor unit 28a, 28b is provided with a humidity sensor 29a, 29b for detecting indoor humidity and an indoor control circuit section 30a, 30b.

For example, as shown in FIG. 2, when the detected value of each humidity sensor 29a, 29b is 70%RH or more, the minimum opening degree of the electronic flow rate regulating valves 25a, 25b is 50%RH or more.
When set to pulse and the detection value of each humidity sensor 29a, 29b is 70% or less, the electronic flow rate adjustment valve 25a
, 25b is set to 10 pulses. Therefore, when operating two air conditioners, for example, the capacity request from one indoor unit 28a is Max (see SF in FIG. 8), and the capacity request from the other indoor unit 28b is Mi.
In the case of n (see S3 in FIG. 8), when the humidity is 70% or more, the opening degrees of the electronic flow rate regulating valves 25a and 25b are 120 and 50 pulses, respectively. Then, the ability requirement Mi
The amount of super heat in the indoor unit 28b of n is also reduced, and dew does not adhere to the indoor unit 28b or blow out from the indoor unit 28b.

On the other hand, when the humidity is 70% or less, the opening degrees of the electronic flow rate regulating valves 25a and 25b are 120 and 1, respectively.
It becomes 0 pulse. In this case, since the humidity is low, no dew formation occurs.

According to the above embodiment, the electronic flow rate regulating valve 2
In a multi-type heat pump type air-conditioning system that can perform variable capacity control by controlling the flow rate using the indoor units 28a and 25b, a humidity sensor 29a is installed in the indoor units 28a and 28b.
, 29b are provided, and the minimum opening degrees of the electronic flow rate regulating valves 25a, 25b are changed according to the detected values, so that dew condensation in the room can be prevented regardless of humidity conditions.

FIGS. 3 to 6 show an embodiment according to the second aspect of the invention.

In this embodiment, a variable capacity compressor 31, an outdoor heat exchanger 33 as a condenser, an electric expansion valve 34 as a refrigerant throttling mechanism, and an indoor heat exchanger 36 as an evaporator are sequentially installed. are connected to form a closed refrigeration cycle. Here, the electric expansion valves 34 (34a, 34b
) and the indoor heat exchanger 36 (36a, 36b) are provided as two sets of indoor units 42a, 42b corresponding to the number of rooms that require air conditioning, for example, two rooms, thereby creating a multi-type air conditioner. is configured.

A control circuit section 39 for varying the capacity is connected to the compressor 31, and the detected values of the evaporation temperature sensor 52 and the compressor suction refrigerant temperature sensor 53 are input thereto. Note that 54 is a capillary tube.

In this device, each indoor heat exchanger 36
Temperature sensors 43a and 43b for detecting the refrigerant temperature are provided at the refrigerant outlet portions of the indoor units 42a and 36b.
a, 42b, a humidity sensor 44a that detects indoor humidity
, 44b are provided. And each of these sensors 4
Signals from 3a, 43b, 44a, 44b, 52, 53 are input to the control circuit section 39 and processed, and the electric expansion valves 34a, 34b are controlled as described below.

That is, FIG. 4 is a flowchart showing the control procedure, and FIGS. 5 and 6 are graphs showing the operation.

Here, the room in which one indoor heat exchanger 36a is installed is designated as room A, and the room in which the other indoor heat exchanger 36b is installed is designated as room B.

Let the required ability value of room A be QA, and the required ability value of room B be QB.

Let VA be the opening degree of the electric expansion valve 34a corresponding to the indoor heat exchanger 36a in room A, and VB be the opening degree of the electric expansion valve 34b corresponding to the indoor heat exchanger 36b in room B. Let ts be the detected value of the temperature sensor for detecting the temperature of the refrigerant sucked into the compressor 31, let tsa be the detected value of the outlet refrigerant temperature sensor from the indoor heat exchanger 36a of room A, and let the outlet from the indoor heat exchanger 36b of room B be Let the refrigerant temperature sensor detection value be tsb.

Let te be the detected value of the evaporation temperature sensor.

[0042] As shown in FIG. 4, first, each room A
, B are read (step a), and the output setting (QA+Q) is performed based on the compression function calculation.
B) is done (step b).

Next, each temperature sensor detection value tsa, tsb
, te, and ts are measured, and calculations are performed based on the measurements (step c). That is, the refrigerant superheat degree ΔTSH (
= ts-te), refrigerant superheat degree ΔTSHA (=ts
a-te), ΔTSHB (=tsb-te), and the upper limit value ΔMax of the degree of superheating.

[0044] Then, the refrigerant superheat degree ΔTSHA, Δ
Judgment whether TSHB does not exceed the upper limit value ΔMax (Δ
TSHA≦ΔMax, ΔTSHB≦ΔMax) is performed (step d). Here, if YES, the expansion valve opening ratio (VA/VB) corresponding to the capacity ratio (QA/QB) of each chamber.
) is set (step e), and then the refrigerant superheat degree Δ
TSH is a constant value ΔTO (ΔTO is a positive value, for example 5d
The full opening degree (VA+VB) is adjusted so that the opening degree (VA+VB) becomes (eg, eg° C.) (step f). Note that the opening ratio VA/VB remains constant.

In step d, if NO, that is, if it is determined that either of the refrigerant superheat degrees ΔTSHA or ΔTSHB in each chamber exceeds the upper limit value ΔMax, the process proceeds to determination and adjustment.

First, ΔTSHA>ΔMax is determined (step g). If YES, the opening degree VA of the electric expansion valve 34a is adjusted so that ΔTSHA≦ΔMax (step h). Further, in the case of NO and after step h, it is determined that ΔTSHB>ΔMax (step i). If YES here, the opening degree VB of the electric expansion valve 34b is adjusted so that ΔTSHB≦ΔMax (
If NO in step j), no adjustment is necessary and the process proceeds to step f.

The above control will be explained in detail as follows. That is, the expansion valve full opening degree VA+VB is based on the detection value of the temperature sensor for detecting the temperature of the refrigerant sucked into the compressor and the detection value of the evaporation temperature sensor (temperatures ts°C, te°C), so that ts-te=ΔTSH becomes a constant value ΔTO. However, the outlet refrigerant temperature of each chamber is different from the sensor detection value. In other words, the refrigerant superheat degree (TSA
-te)=ΔTSHA, (tsb-te)=ΔTSHB
In general, the expansion valve opening degree is small in the room with less demand for capacity (Room A), and ΔTSHA>ΔTO, ΔTSHB<ΔTO
becomes.

In this case, the sensor detection value tsa-tA=A
, tsb-tB=A, if the opening degree of the electric expansion valve is controlled, the refrigerant branch flow will no longer comply with the capacity requirements of each chamber.

However, when the difference in capacity requirements between rooms A and B increases (assuming that the capacity of room B becomes constant and the capacity of room A decreases, as shown in FIG. 5), Although the degree of superheat ΔTSHB does not change much, the degree of superheat ΔTSHA on the side of room A becomes extremely large. Therefore, in room A, the refrigerant in the indoor heat exchanger completes evaporation in the middle of the heat exchanger and near the inlet, and becomes superheated gas. In this state, the indoor air that passes through the heat exchanger is cooled and reaches the dew point, and air that passes through the heat exchanger without being cooled much, and these two types of air mix and reach the dew point. A phenomenon occurs in which dew adheres or blows out from the air that reaches the surrounding area. Therefore, the A chamber expansion valve cannot be narrowed down to an extreme degree, and the capacity control range cannot be widened in response to imbalances in each chamber.

However, the occurrence of such a condition becomes more pronounced as the indoor humidity increases, and when the humidity is low,
It has been found that ΔTSHA can be made quite large. Therefore, the humidity of the indoor air is detected by the humidity sensors 44a and 44b of each indoor unit 42a and 42b.
As shown in FIG. 2, an upper limit value ΔMax is set for the superheat degrees ΔTSHA and ΔTSHB of each room, and this value is set to increase as the humidity decreases. During operation, this upper limit value ΔMa
When x is exceeded, if the electric expansion valve is controlled not to be throttled any further, control can be performed to widen the capacity variable range as much as possible. The entire superheat is performed by ΔTO control.

According to the present embodiment described above, the humidity sensors 44a and 44b are provided for each indoor unit 42a and 42b, and the amount of superheat of the refrigerant is detected for each indoor unit 42a and 42b. 44a
, 44b, each indoor unit 42a, 42
By changing the superheat upper limit value of b, and controlling the opening degrees of the electric expansion valves 34a and 34b so as not to exceed this upper limit value, even when the required capacity of each room is unbalanced, a specific Avoid over-throttling the chamber valve. Therefore, the superheat becomes large and the indoor unit 42
It becomes possible to reliably prevent phenomena such as occurrence of dew on parts a and 42b.

That is, humidity sensors 44a, 44 are provided in each room.
b, and the upper limit of the degree of superheating of the refrigerant in each room is made variable depending on the humidity situation, so the electric expansion valves 34a and 34b can be throttled down to the minimum while suppressing dew formation, and each room can be used as a multi-system. This enables operation with a wide range of capacity control.

[0053]

Effects of the Invention As detailed above, according to the invention of claim 1, in a multi-type heat pump type air conditioner whose capacity can be variably controlled by controlling the flow rate with an electronic flow rate adjustment valve, the humidity in the room can be adjusted. Since a sensor is provided and the minimum opening degree of each flow rate control valve is changed according to the detected value, it is possible to prevent phenomena such as dew formation or misting in the room, regardless of humidity conditions.

Further, according to the invention of claim 2, each indoor unit is provided with a humidity sensor, and the upper limit of the degree of superheating of the refrigerant in each room is made variable depending on the humidity condition, so that the flow rate can be adjusted while suppressing the dew formation phenomenon. You can narrow down the valve for use to the minimum,
As a multi-system, operation with a wide range of capacity control for each indoor unit is possible.

[Brief explanation of the drawing]

FIG. 1 is a system diagram showing an embodiment of the invention according to claim 1.

FIG. 2 is a graph showing the effect of the above embodiment.

FIG. 3 is a system diagram showing an embodiment of the invention according to claim 2.

FIG. 4 is a flowchart showing the operation of the above embodiment.

FIG. 5 is a graph showing the effect of the above embodiment.

FIG. 6 is a graph showing the effect of the above embodiment.

FIG. 7 is a refrigeration cycle diagram showing a conventional air conditioner.

FIG. 8 is a diagram showing the relationship between the indoor required capacity and the electronic flow control valve in a conventional air conditioner.

FIG. 9 is a refrigeration cycle diagram showing another conventional air conditioner.

FIG. 10 is a refrigeration cycle diagram showing another conventional air conditioner.

[Explanation of symbols]

21 Compressor 22 Four-way valve 23 Outdoor heat exchanger 24 Expansion valve 25 Electronic flow control valve 26 Indoor heat exchanger 27 Solenoid valve 28 Indoor unit 29a, 29b Humidity sensor 31 Compressor 33 Outdoor heat exchanger 34 Electric expansion valve 36 Indoor heat exchanger 42 Indoor unit 44a, 44b Humidity sensor

Claims (2)

[Claims] 1. A refrigeration cycle includes a plurality of indoor units arranged in parallel and a valve for controlling a refrigerant flow rate for each indoor unit, and each flow rate is controlled based on the required capacity from each indoor unit. In a multi-type heat pump type air conditioner that performs variable capacity control by determining the opening degree of a valve for each indoor unit and controlling the flow rate of refrigerant to each indoor unit, each indoor unit is provided with a humidity sensor,
An air conditioner characterized in that during cooling operation, the minimum opening degree of each of the flow rate control valves can be changed according to the detected value of the humidity sensor. 2. A refrigeration cycle includes a plurality of indoor units arranged in parallel and a valve for controlling the refrigerant flow rate for each indoor unit, and the compression function is adjusted based on the required capacity from each of the indoor units. In a multi-type air conditioner, the opening ratio of each flow rate control valve is determined and the opening degree of each flow rate control valve is controlled so that the superheat amount of all units is constant. A humidity sensor is provided for each indoor unit, and a superheat upper limit value of each indoor unit is changed according to a detection value of the humidity sensor for each indoor unit and a detection value of a superheat amount of the refrigerant during cooling operation. An air conditioner characterized in that the opening degree of each of the flow rate control valves can be controlled so as not to exceed this upper limit value.