JPH06337128A - Air-conditioner - Google Patents

Abstract

PURPOSE:To prevent a water splashing phenomenon attributable to dust or an oily stain deposited on a heat exchanger from being caused. CONSTITUTION:An air-conditioner according to the present invention comprises a resistant ascending degree detection means A, which detects the degree of ascending DELTAP* of draft resistance of a heat exchanger 4 and a limit wind velocity arithmetic operation means 131, which determines a limit wind velocity of water splash Ulim converted based on the draft wind resistant ascending degree DELTAP* detected by the resistant ascending degree detection means A and an output control means 132, which outputs an operation command to a heat exchanger alarm means 14 when the water splash limit wind velocity Ulim determined by the limit wind velocity arithmetic means 131 is lowered than a design velocity in its operating state.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to an air conditioner,
More specifically, the present invention relates to an air conditioner having a function of warning the necessity of cleaning the heat exchanger.

[0002]

2. Description of the Related Art Generally, an air conditioner is equipped with a means (for example, a warning lamp) that warns of clogging of a filter for adsorbing and removing dust contained in intake air. With the expansion of the range, adhesion of dust and oil stains (oil mist) to the heat exchanger has become a problem.

That is, in a practical environment of an air conditioner (for example, an environment with a lot of dust, an environment in which oil mist is scattered, etc.), dust, oil stains, etc. will adhere to the heat exchanger in the air conditioner. However, there is a problem in that the drain easily adheres to the heat exchanger during the cooling operation, and a phenomenon occurs in which the drain scatters from the air outlet into the room (that is, a water splash phenomenon).

In the conventional air conditioner, unlike the air conditioner disclosed in Japanese Utility Model Laid-Open No. 3-47165, no measures are taken against the above-mentioned water jump phenomenon, and the water jump phenomenon occurs. Therefore, the heat exchanger was washed in a hurry, and the heat exchanger was washed regularly at appropriate intervals.

[0005]

By the way, in order to cope with the expansion of the environment in which the air conditioner is used, the development of a monitoring function that can prevent the phenomenon of water splashing from the heat exchanger to the room is awaited. Has been.

Therefore, the inventors of the present invention used an air conditioner having a structure as shown in FIG. 1 to limit the amount of water, such as dust and oil stains, to the heat exchanger due to the amount X (g / Falm ² ) of water splash. Wind speed Ulim (m
/ Sec) and the degree of increase in ventilation resistance of the heat exchanger (in other words, the rate of change in thermal cross pressure ΔP *) were examined by experiments, and the results shown in FIGS. 9 and 10 were obtained. It was

According to this, the amount of dirt attached to the heat exchanger X
As the thermal cross pressure change rate (in other words, ventilation resistance increase degree) ΔP * increases, the water-spreading limit wind speed Ulim tends to decrease, and in an air conditioner in an actual operating environment, Indicates that the water jump limit wind speed Ulim decreases with the operating time, and the operating wind speed at that time (in other words,
It can be estimated that the water splash phenomenon will occur when the speed becomes smaller than the design wind speed. Therefore, if the degree of increase in ventilation resistance in the heat exchanger can be detected by some means, the water jump limit wind speed can be easily calculated based on this.

The present invention has been made in view of the above points, and it is an object of the present invention to prevent the phenomenon of water splashing caused by the attachment of dust, oil stains, etc. to a heat exchanger. It is what

[0009]

According to the invention of claim 1, as a means for solving the above-mentioned problems, as shown in the drawings, a resistance increase degree for detecting an increase degree ΔP * of ventilation resistance of the heat exchanger 4 Limit wind speed calculation means 131 for calculating the water jump limit wind speed Ulim based on the detection means A and the ventilation resistance increase degree ΔP * detected by the resistance increase degree detection means A.
And the water jump limit wind speed Ulim obtained by the limit wind speed calculation means 131 is the design wind speed U ₁ in the operating state at that time.
The output control means 132 is provided to output an operation command to the heat exchanger cleaning warning means 14 when the temperature becomes lower.

In the invention of claim 2, as means for solving the above-mentioned problems, as shown in the drawings, in the air conditioner of claim 1, the resistance increase degree detecting means A is provided.
Is a rotation speed detection means 11 for detecting the rotation speed N of the fan 5.
And the first arithmetic circuit 12 for calculating the ventilation resistance increase degree ΔP * of the heat exchanger 4 based on the rotational speed N detected by the rotational speed detection means 11 and the fan characteristic.

In the invention of claim 3, as a means for solving the above-mentioned problems, as shown in the drawings, in the air conditioner of claim 1, the resistance increase degree detecting means A is provided.
Is a differential pressure detecting means 16 for detecting the differential pressure ΔP between the upstream side and the downstream side of the heat exchanger 4, and the ventilation resistance of the heat exchanger 4 based on the differential pressure ΔP detected by the differential pressure detecting means 16. The second arithmetic circuit 17 calculates the degree of increase ΔP *.

According to the invention of claim 4, as means for solving the above-mentioned problems, as shown in the drawings, said claim 1,
In the air conditioner according to 2 or 3, the heat exchanger 4 is joined to a plurality of heat transfer tubes 6, 6 ... The mesh fin heat exchanger is composed of a large number of meshed fins 7, 7 ,.

[0013]

According to the first aspect of the invention, the following actions can be obtained by the above means.

That is, when the water-boundary limit wind speed Ulim obtained based on the ventilation resistance increase degree ΔP * in the heat exchanger 4 becomes lower than the design wind speed U ₁ at that time, the heat exchanger cleaning warning means 1
4 is operated to inform the user of the cleaning time of the heat exchanger 4.

According to the second aspect of the invention, the following effects can be obtained by the above means.

That is, the ventilation resistance increase degree ΔP * of the heat exchanger 4 is obtained based on the rotation speed N of the fan 5 and the fan characteristics.

According to the third aspect of the invention, the following actions can be obtained by the above means.

That is, the ventilation resistance increase degree ΔP * of the heat exchanger 4 is obtained based on the pressure difference ΔP between the upstream side and the downstream side of the heat exchanger 4.

According to the invention of claim 4, the following effects can be obtained by the above means.

That is, it is possible to prevent the phenomenon of water splashing when using a mesh fin heat exchanger to which dust, oil stains and the like tend to adhere.

[0021]

According to the invention of claim 1, the resistance increase degree detecting means A for detecting the increase degree ΔP * of the ventilation resistance of the heat exchanger 4, and the ventilation resistance detected by the resistance increase degree detecting means A. The limit wind speed calculating means 131 for calculating the water jump limit wind speed Ulim based on the degree of increase ΔP *, and the water jump limit wind speed Ulim calculated by the limit wind speed calculating means 131 is lower than the design wind speed U ₁ in the operating state at that time. Output control means 132 for outputting an operation command to the heat exchange cleaning warning means 14 when the heat exchange cleaning warning means 14 is reached, and the water jump limit wind speed Ulim obtained based on the ventilation resistance increase degree ΔP * in the heat exchanger 4 is then Since the heat exchange cleaning warning means 14 is made to operate when the wind speed becomes lower than the design wind speed U ₁ , the user can be accurately warned of the cleaning time of the heat exchanger 4, and the drain will be discharged indoors. There is an excellent effect that the splashing of water can be prevented and the maintenance cost can be reduced by optimizing the cleaning time of the heat exchanger.

According to the invention of claim 2, in the air conditioner according to claim 1, the resistance increase degree detecting means A, the rotation speed detecting means 16 for detecting the rotation speed N of the fan 5, and the rotation speed. Based on the rotation speed N and the fan characteristics detected by the detection means 16, the ventilation resistance increase degree ΔP * of the heat exchanger 4
Since it is configured by the first arithmetic circuit 12 for calculating the above, the excellent effect that the ventilation resistance increase degree ΔP * of the heat exchanger 4 can be obtained only by detecting the rotation speed N of the fan 5 is obtained. is there.

According to the third aspect of the present invention, in the air conditioner according to the first aspect, the resistance increase degree detecting means A is used to detect the differential pressure ΔP between the upstream side and the downstream side of the heat exchanger 4. The detection means 16 and the second calculation circuit 17 for calculating the ventilation resistance increase degree P * of the heat exchanger 4 based on the differential pressure ΔP detected by the differential pressure detection means 16 are used. In addition to the excellent effect that the ventilation resistance increase degree ΔP * can be obtained only by detecting the differential pressure ΔP before and after the heat exchanger 4, the differential pressure ΔP of the heat exchanger 4 is directly detected, so that a detection error occurs. It also has the effect of being kept small.

According to the invention of claim 4, in the air conditioner according to claim 1, 2 or 3, a plurality of heat exchangers 4 are arranged in parallel, and the heat transfer tubes 6, 6 ... 6,6
.. is a mesh fin heat exchanger consisting of a large number of mesh fins 7, 7 ... Joined in parallel with the tube axis, so that a mesh to which dust, oil stains, etc. easily adhere There is an excellent effect that the water splash phenomenon in the fin heat exchanger can be prevented in advance.

[0025]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Some preferred embodiments of the present invention will be described below with reference to the accompanying drawings.

Embodiment 1 FIGS. 1 to 3 show an air conditioner according to Embodiment 1 of the present invention. The present embodiment corresponds to the inventions of claims 1, 2 and 4.

In the air conditioner of this embodiment, as shown in FIG. 2, a heat exchanger is installed in a main body casing 1 having a substantially vertically long rectangular parallelepiped shape having an air intake port 2 in the upper front portion and air blown out air 3 in the lower front portion. 4 and a fan (in this embodiment, a cross flow fan) 5 are arranged. In the case of the present embodiment, as shown in FIG. 3, the heat exchanger 4 includes a plurality of heat transfer tubes 6 and 6 arranged in parallel, and the heat transfer tubes 6 and 6.
, And a mesh fin heat exchanger composed of a large number of mesh fins 7, 7 ... Joined in parallel to the tube axis. In the case of the mesh fin heat exchanger 4, since the air flow flows so as to be orthogonal to the mesh fins 7, 7, ..., It has a structure in which dust, oil stains and the like are easily attached. Reference numeral 8 is a filter, 9 is a drain pan, and 10 is a wind direction adjusting blade.

In this air conditioner, the air suction port 2
When the air W sucked from the air is passed through the heat exchanger 4, it is heated or cooled to be conditioned air, and this conditioned air is blown into the room from the air outlet 3 to perform indoor air conditioning. .

Therefore, in the air conditioner of this embodiment, the rotation speed sensor 11 acting as a rotation speed detecting means for detecting the rotation speed N of the fan 5, the rotation speed N detected by the rotation speed sensor 11, and A first calculation circuit 12 for calculating a ventilation resistance increase degree ΔP * of the heat exchanger 4 (where ΔP ₀ is an initial ventilation resistance) based on the fan characteristics;
A control unit 13 that outputs a control signal based on a signal input from the arithmetic circuit 12; a heat exchange cleaning warning lamp 14 that operates as a heat exchange cleaning warning unit that is operated by the control signal output from the control unit 13; A filter cleaning warning lamp 15 which is operated by a control signal output from the control unit 13 is additionally provided. In the case of the present embodiment, the rotation speed sensor 11 and the first arithmetic circuit 12 serve as resistance increase degree detection means A for detecting the ventilation resistance increase degree ΔP * of the heat exchanger 4.

The control unit 13 is composed of, for example, a microcomputer, and as shown in the diagram corresponding to the claim in FIG. 1, the control unit 13 skips water based on the ventilation resistance increase degree ΔP * detected by the resistance increase degree detecting means A. Limit wind speed calculation means 131 for calculating the limit wind speed Ulim by calculation
And the water jump limit wind speed Ulim obtained by the limit wind speed calculation means 131 is the design wind speed U ₁ in the operating state at that time.
Output control means 132 for outputting an operation command (that is, a lighting command) to the heat exchange cleaning warning lamp 14 and the filter cleaning warning lamp 15 when the temperature becomes lower.

Next, the operation of the air conditioner according to this embodiment will be described with reference to the flow chart shown in FIG.

Firstly, after holding the power supply voltage of the fans 5 fixed in step S _1, the rotational speed N ₁ of the fan 5 is inputted from the speed sensor 11 to the first arithmetic circuit 12 in step S _2, Step S ₃ to S in S _5, the design wind speed U at that time by the first arithmetic circuit 12
₁ and the ventilation resistance increase ΔP * are obtained as follows.

That is, in step S ₃ , the in-machine resistance P ₁ at the time of fan rotation speed N ₁ is obtained using the fan characteristic diagram shown in FIG.
Then, the air volume Q ₁ is obtained, and the average air velocity (in other words, design air velocity) U _{1 at} that time is obtained from the air volume Q ₁ .

Next, in step S ₄ , the in-machine resistance P * at the initial air volume Q ₀ is calculated as P * = P ₁ (Q ₀ / Q ₁ ) ² , and then in step S ₅ , it is calculated from P * / P _0. The ventilation resistance increase ΔP * is obtained.

[0035] When the above way ventilation resistance increases degree [Delta] P * is obtained, from where the relationship shown in FIG. 8 and FIG. 9 is between the ventilation resistance increases degree [Delta] P * and water jump limit wind ULIM, Step S ₆ At, the water jump limit wind speed Ulim is obtained by the limit wind speed calculation means 131.

In step S ₇ , the average wind speed U ₁ obtained in step S ₃ is compared with the water jump limit wind speed Ulim obtained in step S ₆ , and when it is determined that Ulim ≧ U _1. from where the water jump phenomenon is not in the state that occurs, the process proceeds to step S _8, the operation of the air conditioner (in this case, the cooling operation) is continued. On the other hand, if it is determined that ULIM <U ₁ in step S _8, from where there is a risk of water skipping, the process proceeds to step S _9, heat exchanger cleaning warning lamp 14 and filter washed with an instruction from the output control unit 132 The warning lamp 15 is turned on to prompt the user to wash the heat exchanger 4 and the filter 8. The operation of the air conditioner is continued until the maintenance starts. here,
In the case of the present embodiment, the reason for issuing the washing warning of the filter 8 is that the limit water speed Uli is determined based on the rate of change of the inboard resistance P.
This is because, since m is determined, it is taken into consideration that the increase in in-machine resistance due to clogging of the filter 8 is also included. Therefore, even if the heat exchanger cleaning warning lamp 14 is not turned off even after the filter 8 is cleaned, it is determined that the heat exchanger 4 is attached with dust, oil stains or the like. Is washed. In this way, the cleaning cycle of the filter 8 can be optimized. By the way, if the cleaning cycle of the filter 8 is too short, on the contrary, dust, oil stains, etc. may easily adhere to the heat exchanger 4, which may increase the frequency of water splashes. Can be prevented by.

As described above, according to the present embodiment, when the water jump limit wind speed Ulim obtained based on the ventilation resistance increase degree ΔP * in the heat exchanger 4 becomes lower than the average wind speed U ₁ at that time, the heat exchange cleaning is performed. Since the warning lamp 14 is operated, it is possible to accurately warn the user of the cleaning time of the heat exchanger 4, and it is possible to prevent the water splash phenomenon in which the drain splashes into the room, and also to prevent the heat exchanger. The maintenance cost can be reduced by optimizing the cleaning time. Moreover, in the case of the present embodiment, there is also an advantage that the ventilation resistance increase degree ΔP * of the heat exchanger 4 can be obtained only by detecting the rotation speed N of the fan 5.

Embodiment 2 FIG. 6 shows an air conditioner according to Embodiment 2 of the present invention. The present embodiment corresponds to the inventions of claims 1, 3 and 4.

In the case of this embodiment, the resistance increase degree detecting means A for detecting the ventilation resistance increase degree ΔP * acts as a differential pressure detecting means for detecting the differential pressure ΔP between the upstream side and the downstream side of the heat exchanger 4. The differential pressure detector 16 and the ventilation resistance increase degree Δ of the heat exchanger 4 based on the differential pressure ΔP detected by the differential pressure detector 16.
The second arithmetic circuit 17 for calculating P * is used. In the case of this embodiment, the pressure difference ΔP ′ between the upstream side and the downstream side of the filter 8 can also be detected by the pressure difference detector 16. Reference numerals 18, 19 and 20 are pressure detection sensors provided on the upstream side of the filter 8, the downstream side of the filter 8 (in other words, the upstream side of the heat exchanger 4), and the downstream side of the heat exchanger 4. Since other configurations are the same as those in the first embodiment, the description will be omitted to avoid duplication.

Next, the operation of the air conditioner according to this embodiment will be described with reference to the flow chart shown in FIG.

First, in step S ₁ , the power source voltage of the fan 5 is kept constant, and then in step S ₂ , the differential pressure ΔP, Δ between the upstream and downstream of the filter 8 and the heat exchanger 4.
P ′ is input from the differential pressure detector 16 to the second arithmetic circuit 17, and in steps S _{3 to} S ₅ , the second arithmetic circuit 12 determines the design wind speed U ₁ and the ventilation resistance increase ΔP * at that time. Is asked in this way.

[0042] That is, the air volume Q ₁ corresponding to ΔP + ΔP '= ΔP ₁ with fan characteristic diagram shown in FIG. 8 obtained in step S _3, if the average wind speed (in other words at the time from the air volume Q _1, design wind speed ) U ₁ is required.

Next, in step S ₄ , the ventilation resistance increase ΔP * in the heat exchanger 4 is obtained from the differential pressure ΔP of the heat exchanger 4 and the initial air flow Q ₀ .

[0044] When the above way ventilation resistance increases degree [Delta] P * is obtained, from where the relationship shown in FIGS. 9 and 10 is between the ventilation resistance increases degree [Delta] P * and water jump limit wind ULIM, Step S ₅ At, the water jump limit wind speed Ulim is obtained by the limit wind speed calculation means 131.

Then, in step S ₆ , the average wind speed U ₁ obtained in step S ₃ and the water jump limit wind velocity Ulim obtained in step S ₅ are compared, and when it is determined that Ulim ≧ U _1. from where the water jump phenomenon is not in the state that occurs, the process proceeds to step S _7, the operation of the air conditioner (in this case, the cooling operation) is continued. On the other hand, if it is determined that ULIM <U ₁ in step S _6, from where there is a risk of water skipping, the process proceeds to step S _8, heat exchange washing warning lamp 14 is caused to light up by a command from the output control means 132 This prompts the user to clean the heat exchanger 4. The operation of the air conditioner is continued until the maintenance starts.

As described above, also in the case of this embodiment, when the water jump limit wind speed Ulim obtained on the basis of the ventilation resistance increase degree ΔP * in the heat exchanger 4 becomes lower than the average wind speed U ₁ at that time, heat exchange occurs. Since the cleaning warning lamp 14 is operated, it is possible to accurately warn the user of the cleaning time of the heat exchanger 4, and it is possible to prevent the water splash phenomenon in which the drain splashes indoors and to prevent the heat exchange. It is also possible to reduce maintenance costs by optimizing the cleaning time of vessels. Moreover, since the ventilation resistance increase degree ΔP * can be obtained only by detecting the differential pressure before and after the heat exchanger 4, the detection error can be suppressed.

The invention of the present application is not limited to the configuration of each of the above-mentioned embodiments, and it goes without saying that the design can be appropriately changed without departing from the gist of the invention.

[Brief description of drawings]

FIG. 1 is a diagram corresponding to a claim of the present invention.

FIG. 2 is a vertical sectional view showing a schematic configuration of the air conditioner according to the first embodiment of the present invention.

FIG. 3 is a front view of the heat exchanger in the air conditioner according to the first embodiment of the present invention.

FIG. 4 is a flow chart for explaining the operation of the air conditioner according to the first embodiment of the present invention.

FIG. 5 is a fan characteristic diagram of a fan used in the air conditioner according to the first embodiment of the present invention.

FIG. 6 is a vertical sectional view showing a schematic configuration of an air conditioner according to a second embodiment of the present invention.

FIG. 7 is a flowchart for explaining the operation of the air conditioner according to the second embodiment of the present invention.

FIG. 8 is a fan characteristic diagram of a fan used in the air conditioner according to the second embodiment of the present invention.

FIG. 9 is a characteristic diagram showing the relationship between the amount X of oil stain attached to the heat exchanger and the rate of change in thermal cross pressure ΔP *.

FIG. 10 is a characteristic diagram showing the relationship between the amount X of oil stain attached to the heat exchanger and the water splash occurrence limit wind speed Ulim.

[Explanation of symbols]

4 is a heat exchanger, 5 is a fan, 6 is a heat transfer tube, 7 is a mesh fin, 8 is a filter, 11 is a rotation speed detecting means (rotation speed sensor), 12 is a first arithmetic circuit, 13 is a control unit, 14 Is heat exchange cleaning warning means (heat exchange cleaning warning lamp), 16 is differential pressure detection means (differential pressure detector), 17 is the second arithmetic circuit, ΔP * is ventilation resistance increase degree, U ₁ is design wind speed, Ul
im is the water jump limit wind speed, N is the fan speed, and ΔP is the differential pressure.

Claims (4)

[Claims] 1. An increase degree (ΔP) of ventilation resistance of the heat exchanger (4)
*) For detecting the resistance increase degree (A) and the degree of increase in ventilation resistance (ΔP) detected by the resistance increase degree detecting means (A).
Limit wind speed calculation means (131) for calculating the water jump limit wind speed (Ulim) based on *), and the limit wind speed calculation means
Output control that outputs an operation command to the heat exchange cleaning warning means (14) when the water jump limit wind speed (Ulim) obtained by (131) becomes lower than the design wind speed (U ₁ ) in the operating state at that time An air conditioner comprising means (132). 2. The resistance increase detection means (A) is a fan
Rotation speed detection means (11) for detecting the rotation speed (N) of (5);
With the first arithmetic circuit (12) for calculating the ventilation resistance increase degree (ΔP *) of the heat exchanger (4) based on the rotational speed (N) detected by the rotational speed detection means (11) and the fan characteristics. The air conditioner according to claim 1, wherein the air conditioner is configured. 3. The differential pressure detecting means (16) for detecting the differential pressure (ΔP) between the upstream side and the downstream side of the heat exchanger (4), and the differential pressure detecting means (A), A second arithmetic circuit (17) for calculating the ventilation resistance increase degree (ΔP *) of the heat exchanger (4) based on the differential pressure (ΔP) detected by the detection means (16). The air conditioner according to claim 1, which is characterized in that. 4. The heat exchanger (4) comprises a plurality of heat transfer tubes (6), (6), ... Arranged in parallel, and the heat transfer tubes (6), (6). Multiple braided fins joined parallel to the axis
The mesh fin heat exchanger consisting of (7), (7) ,.
Air conditioner described.