JPS6225645Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to an air conditioning system having a heat pump cycle, and more particularly to an air conditioning system that utilizes combustion heat from a combustor as a heat source for a heat pump during heating.

Conventionally, heating devices using a heat pump cycle have been proposed, but since the air is used as the heat source for the heat pump, in winter or in cold regions, when the outside temperature drops, sufficient heat cannot be obtained, the heating capacity decreases, and the heating If the load has a characteristic that the temperature rises slowly and the temperature of the refrigerant flowing into the heat source side heat exchanger is lowered to increase the amount of heat absorbed from the atmosphere, frost will form on the heat exchanger and the heat will increase. This has disadvantages in that the exchange capacity is reduced and the operation of the compressor has to be stopped for defrosting, forcing the heat exchange on the heat radiation side to be stopped.

The present invention provides an air-conditioning and heating system that compensates for the above-mentioned drawbacks by supplying heat using a combustion device, thereby making it possible to increase the heating capacity and eliminate defrosting operation, as well as maintain the heating capacity regardless of the outside temperature. The condensation pressure of the condenser changes depending on the heat exchange efficiency of the heat exchanger that serves as the condenser during heating, and the amount of refrigerant that passes through the bypass passage provided by bypassing the compressor is changed, and the heat exchanger on the heat radiation side The purpose is to obtain a refrigerant circulation amount according to the load.

An embodiment of the present invention will be described below with reference to FIG. FIG. 1 is a refrigerant circuit diagram in the air conditioning system of the present invention.

1 is a compressor, 2 is a four-way valve, 3 is an outdoor heat exchanger, 4 is a pressure reduction mechanism, 5 is an indoor heat exchanger, and 6 is an accumulator, each of which is connected through a refrigerant pipe 7 to form a refrigerant circuit. There is. 8 is a first check valve provided between the outdoor heat exchanger 3 and the pressure reduction mechanism 4 to allow the refrigerant to flow during cooling; 9 is a refrigerant heating heat exchanger, which is connected via piping in parallel with the outdoor heat exchanger 3; A second check valve 10 that allows the refrigerant to flow during heating is provided in the refrigerant inflow pipe 11.

Reference numeral 12 denotes a third check valve, which is connected in parallel to the pressure reducing mechanism 4. A burner 13 is provided adjacent to the refrigerant heating heat exchanger 9 to heat it.
14 is a bypass passage, one of which is connected between the four-way valve 2 and the accumulator 6, the other between the compressor 1 and the four-way valve 2, and a capillary tube 15, a solenoid valve 16 and a pressure expansion valve 17 are connected in series. Connected. A pressure detector 18 is provided in a pipe 19 between the four-way valve 2 of the refrigerant circuit and the indoor heat exchanger 5, and is connected to the pressure expansion valve 21.

In this case, the refrigerant flow in the heating cycle is
In the figure, a gas phase refrigerant discharged from a compressor 1 passes through a four-way valve 2, enters an indoor heat exchanger 5, exchanges heat with indoor air, and is condensed and liquefied.

The liquefied refrigerant flows into the refrigerant heating heat exchanger 9 via the third check valve 12 and the second check valve 10.
Here, the refrigerant is heated by high-temperature combustion gas generated by the burner 13, absorbs heat, evaporates, becomes a gas phase, and enters the compressor 1 via the four-way valve 2 and the accumulator 6. Repeat heating cycle. A pressure expansion valve 17 is provided in the bypass passage 14 that bypasses the compressor 1.
Since the electromagnetic valve 16 and the capillary tube 15 are provided in series, a part of the refrigerant discharged from the compressor 1 is allowed to pass through during heating operation.

On the other hand, in the cooling cycle, the gas phase refrigerant discharged from the compressor 1 passes through the four-way valve 2, radiates heat into the air in the outdoor heat exchanger 3, condenses and liquefies, passes through the first check valve 8, and then passes through the pressure reducing mechanism 4. The indoor heat exchanger 5 expands adiabatically.
It evaporates into a gas phase and returns to the compressor 1 via the four-way valve 2 and the accumulator 6, forming a known refrigeration cycle.

Here, a pressure detector 18 is provided in the refrigerant circuit which is on the high pressure side during heating. The pressure sensor 18 can be controlled by the displacement of a bellows, or controlled by detecting strain, or can produce a mechanical change or a change in electrical signal output based on pressure.

Here, in the refrigerant circuit according to the present invention, there is no pressure reduction mechanism between the indoor heat exchanger 5 and the refrigerant heating heat exchanger 9, and therefore the effect of adiabatic expansion is small, so the compression ratio is The temperature of the refrigerant at the outlet of the compressor 1 is equal to or higher than the temperature of the refrigerant sucked into the compressor 1 in the conventional system. In other words, since the temperature rise value is small, the degree of superheating can be increased, and since the evaporation pressure is supplied with heat from the burner 13, it is possible to increase the evaporation pressure, and the difference from the condensation pressure is small. The compression ratio is small, so the compression work is smaller than that of conventional heat pumps.

However, because the compression ratio is small and the evaporation pressure is high, the amount of refrigerant sucked up by the compressor increases, and the amount of refrigerant circulated increases.Assuming that the heating capacity is constant, as the evaporation pressure increases, the compressor 1
It is necessary to reduce the discharge amount. The purpose of this invention is to balance the increase in discharge amount with the required circulation amount by providing a bypass passage 14 from the discharge side to the suction side of the compressor 1 and returning a part of the discharged refrigerant from the discharge side to the suction side. It's been a long time since I've been in the middle of a long time. Since the bypass passage 14 is not needed during cooling, a solenoid valve 16 is provided and closed during cooling operation.

In the refrigerant circuit of the present invention, the required circulation amount of the main refrigerant circuit which discharges from the compressor 1 and returns to the compressor 1 via the indoor heat exchanger 5 and endothermic heat exchanger 9 is determined by the condensation pressure and the evaporation pressure. The condensation pressure changes depending on the degree of condensation of the indoor heat exchanger 5 serving as a condenser, that is, the condensation pressure changes depending on the temperature of the air passing through the indoor heat exchanger 5 and the amount of air.

Therefore, in order to stabilize the system of the main refrigerant circuit, it is necessary to adjust the amount of refrigerant passing through the bypass passage 14. A capillary tube 15 is provided as a mechanism for adjusting the temperature and volume of air passing through the indoor heat exchanger 5 to an optimal circulation volume that maximizes the heating capacity and minimizes the compressor input under certain conditions, and the amount of refrigerant passing through the bypass passage 14 is adjusted.
The flow rate of refrigerant passing through the bypass passage 14 by this means is an optimum amount under certain conditions as described above, and the amount deviates from the optimum circulation amount range for various conditions of the air passing through the indoor heat exchanger 5.
In this device, the bypass amount is adjusted according to the temperature and volume of the air passing through the outdoor heat exchanger 5. During heating, the indoor heat exchanger 5 acts as a condenser and is the high-pressure side of the refrigerant circuit. The condensation pressure (high-pressure pressure) changes as follows depending on the air temperature and volume:

Low indoor temperature. Large air volume...low pressure and high indoor temperature. Low air volume...high pressure When the condensing pressure is low, the ratio of the bypass volume to the circulation volume of the main refrigerant circuit becomes large, and the main refrigerant circuit
Shows signs of refrigerant deficiency. A high condensing pressure exhibits the opposite symptoms to that of a low condensing pressure. Here, a pressure expansion valve 17 for flow rate adjustment is provided which changes the degree of opening of the valve depending on the condensation pressure. The pressure expansion valve 17 has a pressure sensor 18 that detects condensation pressure.
According to the pressure change, the amount of bypass is changed so as to match the pressure condition. Further, by arranging the pressure expansion valve 17 in series with the capillary tube 15, the change in bypass amount due to the degree of opening of the pressure expansion valve 17 is made gentle.

As described above, in this invention, during heating, by adjusting the amount of refrigerant passing through the bypass path according to changes in condensing pressure, fluctuations in the refrigerant circuit due to changes in air passing through the indoor heat exchanger are suppressed and stabilized. I can drive.

[Brief explanation of the drawing]

The figure is a refrigerant circuit diagram showing the heating and cooling device of the present invention. 1 is a compressor, 5 is an indoor heat exchanger, 9 is a refrigerant heating heat exchanger, 14 is a bypass path, 15 is a capillary tube,
16 is a solenoid valve, 17 is a pressure expansion valve, and 18 is a pressure detector.

Claims (1)

[Scope of utility model registration request] In a heating and cooling system configured to heat a refrigerant flowing in a heat exchanger that serves as an evaporator during heating with high-temperature gas generated by combustion, a bypass path that bypasses a compressor, a solenoid valve,
A pressure expansion valve and a capillary tube are installed in series to increase the amount of refrigerant passing through the pressure expansion valve when the condensation pressure increases.
1. An air-conditioning and heating system characterized in that a pressure sensor is used to control the amount of refrigerant passing through a pressure expansion valve when the condensing pressure is low.