JPH10292936A - Air conditioning system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To efficiently perform the thermal storage utilizing room cooling operation without increasing the size of an ice thermal storage unit by providing a thermal storage utilizing time regulating means to regulate the thermal storage utilizing time during the thermal storage utilizing room cooling operation. SOLUTION: A timer measures the time, for example, eight o'clock to nine o'clock in the morning, and from the noon to one o'clock in the afternoon, and a timer contact 45 is closed during this time. While the timer contact 45 is opened, a resistor 43 does not function. Thus, if the temperature in an ice thermal storage tank is, for example, <=10 deg.C, the thermal storage utilizing room cooling operation is performed on the condition of the request of the room cooling operation from an indoor unit. The timer contact 45 is closed from eight o'clock to nine o'clock and from the noon to one o'clock in the afternoon. When the contact is closed, the resistor 43 functions, and the temperature is judged to be constantly >=20 deg.C even when the temperature in the ice thermal storage tank is <=10 deg.C. Thus, even at the request of the room cooling operation from the indoor unit, the thermal storage utilizing room cooling operation is not performed, and the regular non-thermal storage room cooling operation is performed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an air conditioning system having an ice heat storage unit and conducting a cooling operation utilizing heat storage by guiding a refrigerant cooled through the ice heat storage unit to an indoor unit.

[0002]

2. Description of the Related Art Generally, an ice heat storage unit is provided between an outdoor unit and an indoor unit. For example, during a low electricity rate period from 10:00 at night to 8:00 in the next morning, the liquid refrigerant from the outdoor unit is supplied to the ice storage unit. Supply ice to the heat storage unit to make ice, for example, in the daytime, when the temperature rises, circulate the liquid refrigerant from the outdoor unit to the ice heat storage unit to produce a supercooled liquid refrigerant, An air conditioning system that supplies a liquid refrigerant to an indoor unit to perform a cooling operation using heat storage is known.

[0003] In this type of air conditioning system, when there is a request for cooling operation from the indoor unit and the temperature in the ice storage tank of the ice storage unit is, for example, 10 ° C or less, the cooling operation utilizing heat storage is unconditionally performed. It is common to do it.

[0004]

However, in an air conditioning system in which the maximum amount of heat stored in the ice heat storage unit is used up, for example, 8 hours, if there is a continuous demand for the above-mentioned cooling operation using heat storage, it will Assuming that the operation is started at 8:00, the amount of heat stored in the ice storage unit is exhausted at 4:00 in the evening. Therefore, after 4:00 in the evening, non-heat storage cooling operation is performed, and the refrigerating capacity is reduced. On the other hand, as the time to use up the maximum heat storage amount of the ice heat storage unit, for example, 10
If the time is set to be longer than the time, the maximum heat storage amount of the ice heat storage unit is increased, so that the equipment is enlarged and the initial cost is increased.

[0005] Therefore, an object of the present invention is to solve the above-mentioned problems of the conventional technology and to provide an air conditioning system capable of efficiently performing cooling operation utilizing heat storage without increasing the size of the ice heat storage unit. It is in.

[0006]

According to the first aspect of the present invention,
In an air conditioning system provided with an ice heat storage unit between an outdoor unit and an indoor unit to enable ice making operation and heat storage use cooling operation, heat storage use time adjustment means for adjusting the heat storage use time during the heat storage use cooling operation is provided. It is characterized by having been provided.

According to a second aspect of the present invention, there is provided an air conditioning system in which an ice heat storage unit is provided between an outdoor unit and an indoor unit to enable an ice making operation and a cooling operation using heat storage. When there is a request and the temperature in the ice heat storage tank of the ice heat storage unit is equal to or lower than a predetermined temperature, means for executing the heat storage utilizing cooling operation, and a request for cooling operation from the indoor unit and the inside of the ice heat storage tank of the ice heat storage unit Even if the temperature is equal to or lower than a predetermined temperature, the heat storage use cooling operation is not performed under predetermined conditions, and the heat storage use time adjustment means for adjusting the heat storage use time during the heat storage use cooling operation is provided. It is characterized by the following.

According to a third aspect of the present invention, in the first or second aspect, the heat storage use time adjusting means includes a timer, and the heat storage use cooling operation is performed within a time set in advance by the timer. It is characterized by not being executed.

According to these inventions, since the heat storage utilization time adjusting means is provided, the heat storage utilization cooling operation is not executed during the time period adjusted by the adjustment means, even if the cooling operation is demanded. Is performed, the heat storage amount of the ice heat storage unit is not easily used up, and the heat storage cooling operation can be performed more efficiently than the conventional one.

[0010]

Embodiments of the present invention will be described below with reference to the drawings.

In FIG. 1, reference numerals 100A and 100B denote outdoor units, respectively. This outdoor unit 100
A and 100B are connected to a plurality of indoor units 300 via an ice heat storage unit 200. The outdoor units 100A, 100B have three compressors 1A, 1B, 1C.
The compressors 1A, 1B and 1C are provided with a four-way valve 3
The outdoor heat exchanger 5 is connected via the. 7 is an electronic control valve, 9 is a receiver tank, and 11 is an accumulator. The outdoor heat exchanger 5 includes an ice heat storage unit 200.
, Three indoor heat exchangers 43, 45, 47 are connected in parallel. Reference numerals 44, 46 and 48 are electronic control valves whose opening degrees are set according to the air conditioning load. The ice storage unit 200 includes a receiver tank 15 and an ice storage tank 1.
7, the electronic control valve MV1, and the electric switching valves SV1, SV2, S
V3 and SV4. E1, E2, and E3 are temperature sensors.

The operation and operation of the refrigerant circuit according to the present embodiment will be described.

Ice making operation For example, during a low electricity rate period from 10:00 at night to 8:00 in the next morning, the liquid refrigerant from the outdoor heat exchanger 5 is stored in the ice heat storage tank 1.
7 to form ice in the heat storage tank 17. The cold stored in the heat storage tank 17 is used for daytime cooling operation as described later.

In this case, as shown in FIG. 1, the electric switching valves SV1 and SV4 in the ice heat storage unit 200 are closed, and the electronic control valve MV1 and the electric switching valve SV2 (SV3) are opened. According to this, the refrigerant from the compressors 1A, 1B, and 1C passes through the outdoor heat exchanger 5 as shown by solid arrows, and then flows into the ice heat storage tank 17 through the electronic control valve MV1,
After passing through the ice heat storage tank 17, the electric switching valve SV2 (S
V3), flows into the gas pipe 29, and is returned to the compressors 1A, 1B, 1C through the four-way valve 3 and the accumulator 11. In this case, the excess liquid refrigerant is stored in the receiver tank 15.

That is, during the ice making operation, the indoor heat exchanger 4
3, 45 and 47 are bypassed, and the refrigerant is evaporated in the ice heat storage tank 17, and the ice making operation is performed in the ice heat storage tank 17. The controller 50 controls opening and closing of various valves.

Cooling operation utilizing heat storage For example, during the daytime when the temperature rises, the liquid refrigerant from the outdoor heat exchanger 5 is circulated to the ice heat storage tank 17 to produce a supercooled liquid refrigerant. The liquid refrigerant in a cooled state is supplied to the indoor heat exchangers 43, 45, and 47, and the cooling operation using heat storage is performed.

The cooling operation using the heat storage is performed by the indoor unit 30.
There is a request for the cooling operation from 0, and the temperature in the ice heat storage tank 17 detected by a temperature sensor (not shown) is, for example, 1
When the temperature is equal to or lower than 0 ° C. (predetermined temperature), the process is executed as follows.

In this case, as shown in FIG. 2, the electric switching valves SV2 and SV3 in the ice heat storage unit 200 are closed, and the electric switching valves SV1 and SV4 (the electronic control valve MV1 if necessary) are opened. According to this, the compressors 1A, 1
After the refrigerant from B and 1C passes through the outdoor heat exchanger 5 as shown by the solid arrow, the ice heat storage tank 17 is passed through the electric switching valve SV1.
After passing through the ice heat storage tank 17, the electric switching valve SV
4. Flow into the indoor heat exchangers 43, 45, 47 through the electronic control valves 44, 46, 48, and
The refrigerant having passed through 47 is returned to the compressors 1A, 1B and 1C through the gas pipe 29 and the four-way valve 3. The controller 50 controls opening and closing of various valves.

That is, during the cooling operation using the heat storage, the refrigerant is supercooled in the ice heat storage tank 17 by the cold stored by the ice making operation, and then the indoor heat exchanger 43,
Since it supplies to 45 and 47, the capacity at the time of cooling operation increases.

Next, control for opening and closing the electronic control valve MV1 will be described.

When any of the indoor heat exchangers 43, 45, and 47 is unloaded during the above-described cooling operation using heat storage, the indoor heat exchangers 43 and 45 that are unloaded are operated.
The openings of the electronic control valves 44, 46, 48 of 45, 47 are reduced via the controller 50. That is, in the ordinary cooling operation (non-heat storage cooling operation) control other than the heat storage cooling operation, the coil temperature (evaporation temperature) E2 of the indoor heat exchangers 43, 45, and 47 and the inlet of the indoor heat exchangers 43, 45, and 47 The electronic control valves 44 and 44 through the controller 50 so that the difference from the temperature E1 (= E2-E1) becomes a predetermined temperature difference.
Since the opening degrees of the valves 46 and 48 are controlled, during the unloading operation, control is performed to reduce the supply amount of the refrigerant in order to increase the inlet temperature E1 by the amount corresponding to the increase in the evaporation temperature E2.

In this case, if the supercooled refrigerant continues to be supplied to the indoor heat exchangers 43, 45, and 47 that are operated to be unloaded through the ice heat storage tank 17, the refrigerant at the outlet of the ice heat storage tank 17 The temperature E3 may be lower than the evaporation temperature E2.

When the refrigerant temperature E3 decreases, the inlet temperature E1 of the indoor heat exchangers 43, 45 and 47 also inevitably decreases. Therefore, the coil temperature (evaporation temperature) E2 of the indoor heat exchangers 43, 45 and 47 is reduced. Since the difference (= E2-E1) from the inlet temperature E1 of the indoor heat exchangers 43, 45, 47 becomes larger than the predetermined temperature difference, the opening of the electronic control valves 44, 46, 48 is adjusted according to the normal cooling operation control. Control for increasing the size is performed.

In short, if this state is left unattended, during the unload operation, the electronic control valves 44, 46, and 48 respond in a so-called reverse response to control the flow rate where the control for reducing the flow rate should normally be performed. Control to increase,
Refrigerant evaporation in the indoor heat exchangers 43, 45, and 47 becomes insufficient, causing a problem of liquid back of the compressor.

In order to prevent this, when the refrigerant temperature E3 at the outlet of the ice heat storage tank 17 becomes lower than the evaporation temperature E2,
The opening degree of the electronic control valve MV1 in the ice heat storage unit 200 in the fully closed state is appropriately opened, and the refrigerant from the outdoor heat exchanger 5 is combined with the supercooled refrigerant to increase the temperature E3 of the refrigerant. The electronic control valves 44, 46,
48 reverse responses are avoided.

According to this embodiment, a plurality of outdoor units can be connected. In the example of FIG. 1, two outdoor units 100A and 100B are connected in parallel.
The number of connected units can be changed. That is, for example, three or four or more outdoor units are connected according to the air conditioning load. Normally, the capacity of the ice heat storage unit 200 is changed according to the number of connected outdoor units.

In this embodiment, the ice heat storage unit 200
The supercooling control is performed without changing the capacity of the heat storage, and the refrigeration capacity during the cooling operation using the heat storage is changed.

In a normal cooling operation (non-heat storage cooling operation) other than the heat storage cooling operation, a refrigeration capacity E0 according to the total horsepower of the outdoor unit 100 is obtained as shown by a dotted line in FIG. In order to increase the refrigerating capacity E0, it is necessary to increase the degree of supercooling SC. In this embodiment, the degree of supercooling SC is increased by reducing the opening of the electronic control valve MV1 (FIG. 2) in the ice heat storage unit 200.

When the opening of the electronic control valve MV1 is reduced, for example, to a small value, the degree of supercooling becomes SC1, as indicated by the thin line, and the refrigerating capacity increases by E1, and the refrigerating capacity in this case is E1 + E0.
Becomes Looking at the degree of increase in the refrigerating capacity with respect to the refrigerating capacity E0 (hereinafter referred to as “shift rate”), the following equation is obtained.

Shift rate = (E1 + E0) / E0 (1) When the opening of the electronic control valve MV1 is greatly reduced, for example, the supercooling degree becomes SC2 and the refrigerating capacity becomes E2 as shown by the thick line.
The refrigerating capacity in this case becomes E2 + E0. Looking at the above-mentioned shift rate with respect to the refrigerating capacity E0, the following equation is obtained.

Shift rate = (E2 + E0) / E0 (2) In this embodiment, for example, by controlling the temperature difference ΔTn shown in FIG. 3, the shift rate shown in the equations (1) and (2) is controlled.

It is assumed that the number of connected outdoor units has changed and the total refrigerating capacity of the outdoor units has changed from 14 hp to 30 hp as shown in FIG.

In this embodiment, when the total refrigerating capacity of the outdoor unit is equal to or more than a predetermined capacity (for example, 20 horsepower), the refrigerating capacity (corresponding to the indoor unit capacity) during the cooling operation utilizing heat storage is determined by the total refrigerating capacity of the outdoor unit. Is adjusted to a refrigeration capacity that is increased by a constant shift rate (for example, 25%) based on. For example, the total refrigerating capacity of the outdoor unit is 24
In the case of the horsepower, the refrigeration capacity during the cooling operation using the heat storage is adjusted to a refrigeration capacity of 30 hp, which is increased by a constant shift rate of 25% based on the total refrigeration capacity of the outdoor unit of 24 hp, and Is 30 hp, the refrigerating capacity during the cooling operation using heat storage is a constant shift rate of 25% based on the total refrigeration capacity of the outdoor unit of 30 hp.
Refrigeration capacity is increased to 37.5 hp.

In this control, the compressors 1A, 1B, 1C
Assuming that the operation has been performed at 00%, the maximum time during which heat storage can be used gradually decreases as shown in FIG. 4, and decreases to 7.1 hours when the total refrigeration capacity of the outdoor unit is 30 horsepower.

In this embodiment, the capacity of the ice heat storage unit 200 is set so as to correspond to the total refrigerating capacity of the outdoor unit of 20 horsepower (predetermined capacity).

Therefore, the maximum time during which heat storage can be used is 7.1.
The reason for the decrease in time is that the capacity of the ice heat storage unit 200 is significantly short of the total refrigerating capacity of the outdoor unit when the total refrigerating capacity of the outdoor unit is 30 horsepower. If the maximum time during which heat storage can be used is too small for 7.1 hours on the air conditioning system, the maximum time can be extended by setting a low shift rate of 25%.

In this embodiment, when the total refrigerating capacity of the outdoor unit is equal to or less than a predetermined capacity (for example, 20 horsepower), the refrigerating capacity (corresponding to the indoor unit capacity) during the cooling operation utilizing the heat storage is determined by the total refrigerating capacity of the outdoor unit. Is adjusted to a refrigeration capacity increased by a predetermined shift rate equal to or more than a fixed shift rate (for example, 25%). For example, when the total refrigeration capacity of the outdoor unit is 18 hp, the refrigeration capacity during the cooling operation using the heat storage is increased by a predetermined shift rate of 28% which is a constant shift rate of 25% or more according to the total refrigeration capacity of the outdoor unit of 18 hp. If the refrigerating capacity is adjusted to 23 hp and the total refrigerating capacity of the outdoor unit is 14 hp, the refrigerating capacity during the cooling operation using heat storage has a constant shift rate of 25% or more according to the total refrigerating capacity of 14 hp of the outdoor unit. Predetermined shift rate 35
The refrigeration capacity has been adjusted to 19 hp, increased by a percentage.

When the total refrigerating capacity of the outdoor unit is equal to or less than the predetermined capacity, according to this combination, the capacity of the ice storage unit 200 is left over the total refrigerating capacity of the outdoor unit. In this embodiment, as described above, a large shift to a constant shift rate of 25% or more allows the excess heat storage amount to be used to the maximum, so that the refrigerating capacity during the cooling operation using heat storage can be increased.

Referring to FIG. 4, when the total refrigerating capacity of the outdoor unit is, for example, 30 horsepower, the maximum time during which heat storage can be used is 7.1 hours as described above. If the cooling operation is demanded from the indoor unit 300 and the temperature in the ice heat storage tank 17 is 10 ° C. or lower as in the related art, the cooling operation using the heat storage is unconditionally performed. As long as there is a continuous demand, the heat storage amount of the ice heat storage unit 200 will be used up at 3:00 during the day assuming that the operation is started from 8:00 in the morning. Therefore, after 3:00 during the day, non-heat storage cooling operation is performed, and the refrigeration capacity is significantly reduced.

In this embodiment, there is provided a heat storage time adjusting means for adjusting the heat storage time during the heat storage cooling operation. This heat storage utilization time adjusting means includes, for example, a thermistor 41 for detecting the temperature in the ice heat storage tank 17 as shown in FIG.
And a resistor 43 connected in parallel with the thermistor 41.
And a timer (not shown) for adjusting the heat storage utilization time, and a timer contact 45 opened and closed by the timer. For example, as shown in FIG. 6, a timer (not shown) measures between 8:00 and 9:00 in the morning and between 12:00 and 1:00 in the day, and closes the timer contact 45 during this time. When the timer contact 45 is open, the resistor 43 does not function as is apparent from FIG. Therefore, if the temperature in the ice heat storage tank 17 is, for example, 10 ° C. or less, the cooling operation using heat storage is executed on the condition that the cooling operation is requested from the indoor unit 300.
The timer contact 45 is closed between 8:00 and 9:00 in the morning and between 12:00 and 1:00 in the afternoon. When this is closed, the resistor 43 functions, and even if the temperature in the ice heat storage tank 17 is lower than
It is determined that the temperature is 0 ° C. or higher. Therefore, the indoor unit 30
Even if there is a request for the cooling operation from 0, the cooling operation using heat storage is not executed, and the normal non-heat storage cooling operation is executed.

It should be noted that, from 8:00 to 9:00 in the morning and from 12:00 to noon,
The time zone is not limited to this, and it is clear that any time zone may be used as long as there is little demand for the cooling operation using heat storage.

In this embodiment, since the heat storage use time adjusting means is provided, the heat storage use cooling operation is not executed during the time period adjusted by the adjustment means even if the cooling operation is requested, and the normal non-operating time. Since the heat storage cooling operation is executed, the heat storage use cooling operation can be efficiently executed as compared with the conventional heat storage cooling operation without easily using up the heat storage amount of the ice heat storage unit 200. In addition, since the heat storage use time adjusting means including the resistor 43 and the timer contact 45 can be externally attached without changing the control circuit of the controller 50, the heat storage use cooling operation can be efficiently performed without increasing the product cost. Can be performed.

[0043]

According to the present invention, since the heat storage use time adjusting means is provided, the heat storage use cooling operation is not executed in the time zone adjusted by this adjustment means even if the cooling operation is requested, Since the normal non-heat storage cooling operation is performed, the heat storage cooling operation is performed more efficiently than the conventional one.

[Brief description of the drawings]

FIG. 1 is a circuit diagram showing an embodiment of the present invention.

FIG. 2 is a circuit diagram during cooling operation using heat storage.

FIG. 3 is a diagram illustrating a shift rate.

FIG. 4 is a diagram illustrating heat storage utilization time.

FIG. 5 is a diagram illustrating heat storage utilization time adjustment means.

FIG. 6 is a diagram illustrating a heat storage / cooling operation use time zone.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1A, 1B, 1C Compressor 3 Four-way valve 5 Outdoor heat exchanger 17 Ice heat storage tank 41 Sensor 43 Resistance 45 Timer contact 50 Controller MV1 Electronic control valve SV1, SV2, SV3, SV4 Electric switching valve 100A, 100B Outdoor unit 200 Ice heat storage Unit 300 Indoor unit

Claims (3)

[Claims] 1. An air conditioning system in which an ice heat storage unit is provided between an outdoor unit and an indoor unit to enable an ice making operation and a heat storage use cooling operation, wherein the heat storage time for adjusting the heat storage use time during the heat storage use cooling operation is provided. An air conditioning system comprising a use time adjusting means. 2. An air conditioning system in which an ice heat storage unit is provided between an outdoor unit and an indoor unit to enable an ice making operation and a cooling operation utilizing heat storage. When the temperature in the ice heat storage tank is equal to or lower than a predetermined temperature, means for performing the heat storage utilizing cooling operation; and a request for cooling operation from the indoor unit, and the temperature in the ice heat storage tank of the ice heat storage unit is equal to or lower than the predetermined temperature. Air, characterized in that heat storage utilization time adjustment means for adjusting the heat storage utilization time during the heat storage utilization cooling operation is provided without executing the heat storage utilization cooling operation under predetermined conditions even in some cases. Harmony system. 3. The air-conditioning system according to claim 1, wherein the heat storage time adjusting means includes a timer, and the heat storage cooling operation is not performed within a time period preset by the timer. .