JPH0359347B2 - - Google Patents

Description

Detailed Description of the Invention The present invention provides an outdoor unit in which a plurality of indoor units are connected in parallel, in which a refrigerant heater is provided upstream of a compressor, and high-temperature refrigerant gas from the compressor is supplied to the condenser. A bypass passage is provided for bypassing the refrigerant, and a flow switching valve is provided for selectively supplying refrigerant to the condenser and the bypass passage. The present invention relates to a multi-type air-conditioning/heating device provided with a bypass passage with a valve that detours the air from the indoor unit to the indoor unit.

Conventionally, as shown in Japanese Unexamined Patent Publication No. 52-15161, the entire amount of low-temperature refrigerant from the condenser is supplied to the indoor unit by a compressor during cooling, and part of the high-temperature refrigerant gas is supplied during heating. The refrigerant heater was configured to be returned downstream of the refrigerant heater via a bypass path.

However, in multi-type air conditioning systems, there are cases where only some of the indoor units are used for cooling, and in that case, a large amount of refrigerant is used between the outdoor unit and the indoor unit, even though the cooling load is significantly reduced. Disadvantages: The refrigerant is circulated through long refrigerant piping, which unnecessarily increases the load on the compressor, increases operating costs due to increased power consumption, and increases heat loss due to heat input through the refrigerant piping. It was hot.

Additionally, during heating, high-temperature refrigerant gas returns from the bypass path to the downstream side of the refrigerant heater, resulting in a significant reduction in the amount of refrigerant in the refrigerant heater, resulting in a reduction in heat transfer efficiency in the refrigerant heater. .

An object of the present invention is to sufficiently suppress rising operating costs and heat loss even when the cooling load decreases, and also to eliminate a decrease in heating efficiency in a refrigerant heater during heating.

In an outdoor unit in which a plurality of indoor units are connected in parallel, which is a feature of the present invention, a refrigerant heater is provided upstream of the compressor, and a bypass bypasses the high-temperature refrigerant gas from the compressor to the condenser. A flow path switching valve is provided for selectively supplying refrigerant to the condenser and the bypass path, and when the high temperature refrigerant gas is being supplied to the bypass path, a portion of the high temperature refrigerant gas from the compressor is transferred to the room. In a multi-type air-conditioning/heating system that is provided with a bypass passage with a valve that detours around the indoor unit, the inlet is provided with a bypass passage with a valve that detours a part of the low-temperature refrigerant to the indoor unit when the refrigerant is being supplied to the condenser. The high-temperature refrigerant gas bypass is provided in a downstream path of the condenser, with an outlet connected to an upstream side of the compressor, and an inlet of the high-temperature refrigerant gas bypass path is connected to the downstream side of the compressor, and an outlet is connected to the upstream side of the refrigerant heater. The functions and effects are as follows.

When the cooling load decreases, the valve of the bypass path extending from the downstream side of the condenser to the upstream side of the compressor is opened to an appropriate opening degree, so that part of the low-temperature refrigerant can be circulated without being sent to the indoor unit.

Therefore, it is possible to reduce the amount of refrigerant circulated through the long pipes between the outdoor unit and the indoor unit, and the load on the compressor can be kept small. Increases in power consumption by the compressor can be sufficiently suppressed, and cooling operating costs can be reduced. It can be done cheaply. At the same time, the amount of heat input through the piping can be reduced, and heat loss during cooling can be kept to a sufficiently low level.

Furthermore, since high-temperature refrigerant gas is returned from the bypass path to the upstream side of the refrigerant heater during heating, a large amount of refrigerant is constantly flowing in the refrigerant heater, allowing efficient heating of the refrigerant and reducing heating operating costs.

As a result, it has become possible to provide a multi-type air-conditioning and heating system with even higher performance, which can reduce operating power costs and reduce heat radiation loss when cooling and heating loads are reduced.

Next, an example will be described with reference to FIGS. 1 to 3.

The multi-type air conditioning system includes a compressor 1, a condenser 2, and multiple expansion valves 3, 3' (two are shown in the drawing, but
It is possible to have three or more. ), two indoor units B, B' are connected to one outdoor unit A, and branch refrigerant flow paths 12, 12' connecting pipes 13, 13' with the expansion valves 3, 3'interposed; 14 and 14' are connected in parallel.

A valve 10 that detours a part of the low-temperature refrigerant to the indoor units B and B' when the refrigerant is supplied to the condenser 2.
Bypass passages 11, 11″ are connected to the condenser 2.
The outlet is connected to the downstream side of the compressor 1 and the outlet is connected to the upstream side of the compressor 1, and when the cooling load becomes less than the set value during cooling operation, a part of the low-temperature refrigerant from the condenser 2 is transferred to the indoor units B and B. By returning the refrigerant to the compressor 1 without sending it to the refrigerant pipe, the operating cost can be reduced by reducing the load on the compressor 1, and the heat loss due to heat input in the refrigerant piping can be reduced.

Note that the three-way valve 18 connects the compressor 1 to the bypass path 1.
1'', and an expansion valve 19 is provided in the bypass passage 11''.

A refrigerant heater 4, such as a gas combustion type, which operates on and off in conjunction with the room thermostat built into the indoor units B and B', is installed in the outdoor unit A upstream of the compressor 1, and the condenser A bypass path 5 is provided to bypass the high temperature refrigerant gas from the compressor 1 to the condenser 2 and the expansion valves 3 and 3', and the refrigerant is transferred to the condenser 2 and the bypass path 5.
Flow path switching valves 6 and 7 are provided for selectively supplying the water.

Bypass passages 11' and 11'' with valves 10' that detour a part of the high temperature refrigerant gas to the indoor units B and B' when the high temperature refrigerant gas is supplied to the bypass passage 5;
is provided with an inlet connected to the downstream side of the compressor 1 and an outlet connected to the upstream side of the refrigerant heater 4, and when the heating load becomes less than the set value during heating operation, the compressor 1
A part of the high-temperature refrigerant gas from the refrigerant is returned to the refrigerant heater 4 without being sent to the indoor units B and B', reducing operating costs by reducing the load on the compressor 1 and reducing heat loss due to heat radiation in the refrigerant piping. It is designed to reduce the amount of

Bypass passages 9 and 9' are provided for the expansion valves 3 and 3', so that the refrigerant in the condenser 2 can be sufficiently expelled through the bypass passages 9 and 9' at the beginning of heating operation.

In addition, 15 and 15' are on-off valves that cut off the refrigerant supply to the indoor units B and B', and 16 is the branch refrigerant flow path 1.
It is the flow path resistance connecting 2 and 12′, and 1
7 is a bubble separator. Further, the refrigerant heater 4
is provided spatially higher than the compressor 1 and condenser 2, and suppresses insufficient refrigerant circulation amount due to refrigerant liquid remaining in the compressor 1 and condenser 2 during the heating operation cycle described later. We have taken this into consideration.

Next, each operation cycle of the multi-type heating and cooling system configured as described above will be briefly explained.

○B Cooling operation Cooling of one or more rooms is performed using a commonly known refrigeration cycle. Specifically, the refrigerant is transferred from the compressor 1 to the condenser 2 to the expansion valves 3 and 3'. The air is circulated in the order of indoor units B, B'→compressor 1. At this time, valves 6, 15, 15' are open, and valves 8, 8', 7, and 10' are closed.

When the cooling load on the indoor side becomes less than the set value, the three-way valve 18, the bypass flow path 11''
A part of the compressed refrigerant gas is returned to the suction side of the compressor 1 through the above, and the load is adjusted, and the power consumption of the compressor 1 is also reduced.

○B Initial stage of heating operation The refrigerant liquid accumulated in the condenser 2 is expelled to ensure the amount of refrigerant necessary for heating. Specifically, the refrigerant is transferred from the refrigerant heater 4 to the compressor 1. The refrigerant is circulated in the following order: → condenser 2 → bypass paths 9, 9' → indoor units B, B' → refrigerant heater 4. At this time, valves 6, 8, 8' are open, and valves 7, 1
5, 15' and 10, 10' are closed, and combustion in the refrigerant heater 4 is started after the operation of the compressor 1 is confirmed.

○C Normal heating operation This is a mode in which one or more rooms are heated by switching the flow paths as the valves 6 and 7 are closed and opened.
→Compressor 1→Bypass path 5→Indoor unit B, B'→
The refrigerant is circulated in the order of the refrigerant heater 4. At this time, valves 7, 15, 15' are open, valves 6, 8, 8', and 10, 10' are closed, and the heating load on the indoor unit is below a certain level, and the compressor 1 discharge When the detected pressure value on the side reaches a certain level or more, a part of the compressed refrigerant gas is returned to the suction side of the compressor 1 through the three-way valve 18 and the bypass path 11'', load adjustment is performed, and the compressor 1 power consumption is reduced.

Although it is desirable for the device of the present invention to have the above-mentioned initial cycle of heating operation, it is preferable that the device does not have this cycle, that is, it does not have the bypass passages 9, 9' with the valves 8, 8'. Also good.

[Brief explanation of drawings]

The drawings illustrate embodiments of the multi-type air-conditioning and heating system according to the present invention, and FIG. 1 is an explanatory diagram of refrigerant flow during refrigerant operation, FIG. 2 is an explanatory diagram of refrigerant flow during initial heating operation, and FIG. 3 is a diagram of steady state flow. It is an explanatory diagram of a refrigerant flow during heating operation. 1... Compressor, 2... Condenser, 3, 3'... Expansion valve, 4... Refrigerant heater, 5... Bypass path,
6, 7...Flow path switching valve, 11''...Bypass path,
18...Valve, A...Outdoor unit, B, B'...Indoor unit.

Claims (1)

[Claims] 1. In an outdoor unit A in which a plurality of indoor units B and B' are connected in parallel, a refrigerant heater 4 is installed upstream of a compressor 1.
is provided, and the compressor 1 is connected to the condenser 2.
A bypass passage 5 is provided to detour high-temperature refrigerant gas from the bypass passage 5, and passage switching valves 6 and 7 are provided for selectively supplying refrigerant to the condenser 2 and the bypass passage 5. The multi-type air-conditioning and heating system is provided with bypass passages 11' and 11'' with valves 10' for detouring a part of the high-temperature refrigerant gas from the compressor 1 to the indoor units B and B' in the above-mentioned state, A bypass passage 11, 11'' with a valve 10 for detouring a part of the low-temperature refrigerant to the indoor units B, B' when the refrigerant is supplied to the condenser 2 is provided with an inlet on the downstream side of the condenser 2 and an outlet. is connected to the upstream side of the compressor 1, the inlet of the high-temperature refrigerant gas bypass path 11', 11'' is located downstream of the compressor 1, and the outlet is located upstream of the refrigerant heater 4. 2. The multi-type air-conditioning and heating device according to claim 1, wherein the refrigerant heater 4 is provided at a spatially higher position than the compressor 1 and the condenser 2. Device. 3 A plurality of expansion valves 3, 3' connected to the indoor units B, B' respectively are provided in the outdoor unit A, and a bypass path with a plurality of valves 8, 8' is provided for each of the expansion valves 3, 3'. 9, 9' are provided. The multi-type air-conditioning device according to claim 1 or 2.