JPH0123700B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a heating and cooling system in which two indoor units are connected to one outdoor unit and can be heated and cooled by switching a four-way switching valve.

Traditionally, in this type of air conditioning system, especially when operating in multiple rooms, the heating capacity is extremely reduced, so each indoor unit is equipped with an auxiliary indoor heater to compensate for the lack of capacity, and even more so when operating in fewer rooms. Sometimes, it has been proposed to forcibly turn off the power to the heater to save power since the heater has sufficient capacity.

However, when transitioning from multi-room operation to small-room operation due to room temperature thermostats, etc., the heater of the operator's indoor unit is de-energized. However, even if the number of units in operation decreases, the heating capacity of the indoor units in operation will not immediately increase; the capacity can only be demonstrated when the refrigerant is stabilized, and the heating capacity will increase until the refrigerant stabilizes. It was impossible to eliminate the feeling of insufficient capacity and cold air blowing due to the heater being de-energized.

In view of this, the present invention provides an air-conditioning and heating system that eliminates discomfort when transitioning from multi-room operation to small-room operation and enables fine-grained control, while the main objective is to reduce operating costs due to unnecessary heater energization. One embodiment of the present invention will be described below with reference to the accompanying drawings.

In FIG. 1, two indoor units 2a and 2b are connected to one outdoor unit 1 by refrigerant piping. Inside the outdoor unit 1, a compressor 3, a four-way switching valve 4, an outdoor coil 5 which serves as a condenser during cooling and an evaporator during heating, a pressure reducer 6 for heating, a liquid receiver 7, and an accumulator 8 are connected via piping, and a liquid receiver. Liquid side branch pipes 9a, 9b to each unit 2a, 2b are provided to the device 7, and gas side branch pipes 10a, 10 are similarly provided to each unit 2a, 2b to the switching valve 4.
b. Furthermore, electromagnetic valves 11a, 11b, 12a, and 12b are interposed in these branch pipes to control the flow of refrigerant. 13 is an outdoor fan that cools the outdoor coil 5. On the other hand, each indoor unit 2a, 2b has a cooling pressure reducer 14a, 14b,
Indoor coils 15a and 15b, which serve as an evaporator during cooling and a condenser during heating and cooling, are connected to each branch pipe 9a, 9b, 10a, 1.
0b, and is also connected to the auxiliary heater 16 during heating.
a, 16b, and indoor fans 17a, 17b, respectively. Therefore, the operating state of the above system is that during cooling, the refrigerant flows as shown by the solid line arrow in the figure, and during heating, the refrigerant flows as shown by the broken line arrow by switching the four-way switching valve 4, and the refrigerant flows into two rooms or one room by opening and closing the solenoid valve as appropriate. Can be operated indoors.

Next, a schematic electrical circuit diagram focusing on heating operation in the above device will be explained with reference to FIG. 2. Inside each of the above units 2a and 2b, the room temperature is sensed and the ON-
Room temperature thermostats 18a and 18b that are turned off are provided,
Heating operation switches 19a, 19b operated during heating
connected in series with. Further, electromagnetic valve coils 11a', 12a' and 11b', 1 open and close the electromagnetic valves 11a, 12a, 11b, 12b in response to ON/OFF of the room temperature thermostats 18a, 18b.
2b' and heater relays 16a' and 16 for energizing and de-energizing the respective heaters 16a and 16b.
b′ are connected in parallel. The heater relays 16a' and 16b' are connected in series with room temperature thermostats 18a and 16b'.
Thermostat 19 closes at a set temperature lower than 18b
a, 19b and contacts 20b', 20a', which will be described later, are connected in series, and these thermostats 19a, 19b contact 2
Heater 1 is closed only when both 0b' and 20a' are closed.
6a and 16b are configured to be energized. 20
a, 20b are delay relays connected in parallel with each solenoid valve of each unit 2a, 2b, and its contact 20
a', 20b' are the auxiliary heaters 16 of the other unit.
heater relay 16b', to operate b, 16a;
16a' in series. In other words, the delay relays 20a and 20b immediately close their contact 2 when energized.
0a' and 20b' are closed, and the predetermined time (2
The contacts 20a' and 20b' are opened after a delay (about 3 minutes).

That is, to explain the operation of the above circuit, first, when each unit 2a, 2b is operated together, each heating switch 19a, 19b is closed, and if the room temperature in each room is low, the room temperature thermostat 18a, 18b is also closed, so each electromagnetic switch is closed. Valves 11a, 12a, 11b, 12b are closed and refrigerant flows. In addition, since the two-room operation is performed at this time, if the indoor coils 15a and 15b do not reach their full capacity and the room temperature does not rise, the thermostats 19a and 19b are also closed, and the auxiliary heaters 16a and 16b are also energized to supplement heating. . At this time, relays 20a and 20b
The contacts 20a' and 20b' are closed, and the control of the auxiliary heaters 16a and 16b is controlled by the thermostat 1.
According to 9a, 19b.

On the other hand, when only one room, for example, the indoor unit 2a, is operated, the relay 20b is not energized, so the contact 20b' is closed, and the auxiliary heater 16a is not energized regardless of the thermostat 19a. That is, during single-room operation, since the indoor coil 15a has sufficient capacity, the auxiliary heater 16a is forcibly de-energized, thereby eliminating unnecessary operating costs.

Furthermore, when switching from two-room operation to one-room operation, that is, when the room on the indoor unit 2b side is sufficiently heated and the room temperature thermostat 18b is turned off, the refrigerant flow in this unit 2b and the auxiliary heater 1
Although the power to 6b was immediately stopped, relay 20
The contact 20b' of b opens with a delay of 2 to 3 minutes as described above. In other words, in the indoor unit 2a, the heater relay 16a' is energized for 2 to 3 minutes during this switching, so the heater 16a is in the energized state, and then the auxiliary heater 16a is de-energized by opening the contact 20b'. . That is, the indoor coils 15a, 1
Indoor coil 1 from the state where refrigerant was circulating to 5b
Even if the refrigerant is circulated only through the refrigerant 5a, it is not possible to immediately increase the capacity of the indoor coil 15a until the refrigerant flow becomes stable, and during that time the auxiliary heater 16a is energized to compensate for the lack of capacity.

As described above, according to the present invention, operating costs are reduced by forcibly de-energizing the auxiliary heater when heating a small number of rooms, and when transitioning from multi-room operation to small-room operation, the auxiliary heater is Since the power is turned off with a delay, it is possible to prevent discomfort during this time.

[Brief explanation of drawings]

FIG. 1 is a cooling cycle diagram of a heating and cooling system according to an embodiment of the present invention, and FIG. 2 is a schematic electrical circuit diagram mainly used during heating of the system. 1... Outdoor unit, 2a, 2b... Indoor unit, 4... Four-way switching valve, 16a, 16b... Auxiliary heater for heating, 20a', 20b'... Contact.

Claims (1)

[Claims] 1. In a heating and cooling system in which two indoor units, each equipped with an auxiliary heater for heating, are connected to one outdoor unit, and heating and cooling are possible by switching a four-way switching valve, each unit has a thermostat for the auxiliary heater and a thermostat higher than this thermostat. The room temperature thermometer set to A series circuit of the relay for the thermostat, the auxiliary heater, and the contact of the delay relay of the other indoor unit is installed in parallel, and when the number of operating indoor units decreases, the auxiliary heater of the stopped indoor unit is de-energized, and the indoor unit is switched off. An air-conditioning/heating device characterized in that an auxiliary heater is de-energized after a predetermined time delay.