JPS63290365A - Engine drive type air conditioner - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Field of Application) The present invention relates to an engine-driven air conditioner that utilizes engine exhaust heat to increase the heating cycle capacity.

(Prior Art) Some air conditioners use a gas engine as a power source to drive a compressor. Conventionally, this gas engine-driven air conditioner has a compressor 2 driven by a gas engine 1, a four-way valve 3, and a four-way valve 3, as shown in FIG.
An outdoor heat exchanger 4, a pressure reducing device 7 formed by connecting a check valve 5 and an expansion valve 6 in parallel, a pressure reducing device 10 formed by connecting a check valve 8 and a cooling capillary tube 9 in parallel, and an indoor heat exchanger. A heat pump type refrigeration cycle is used in which eleven refrigeration cycle devices are sequentially connected through refrigerant pipes 12. By driving the compressor 2 and switching the four-way valve 3, a cooling cycle or a heating cycle is configured.

However, this heat pump type has a drawback in terms of heating capacity. Therefore, in such an engine-driven heat pump type refrigeration cycle, a structure is provided in which the exhaust heat discarded from the gas engine 1 is utilized to increase the heating capacity. As shown in FIG. 4, a branch passage 13 is provided between the indoor heat exchanger 11 and the pressure reducing device 10 and a cylinder (not shown) of the compressor 2, and this branch passage 13 is A gas injection solenoid valve 14 (for branching the refrigerant during heating operation) and a refrigerant heater (heat exchanger) 15 for heating the refrigerant flowing through the branch path 13 are provided, and the injection circuit 16
Configure. During the heating cycle, hot water heated by the exhaust heat of the gas engine 1 is guided to the refrigerant heater 15, and the refrigerant from the indoor heat exchanger 11 is converted into high-temperature gas through heat exchange and returned to the compressor 2. things are being done. More specifically, the hot water circuit 17 shown in FIG. and arrange the radiator 19 (this is the - group fan 2).
This is due to the fact that air can be blown at 0). And the circulation pump 22
The hot water pipe 21 is equipped with an exhaust heat recovery heat exchanger 18.
18 and the radiator 19 are connected to form a hot water closed circuit 23. Further, the refrigerant heater 15 is connected in parallel to the inflow and outflow sides of one radiator using a hot water pipe 24 to form a hot water supply circuit 25. Further, solenoid valves 26a and 26b are provided on the inflow side of one radiator and the inflow side of the refrigerant heater 15, respectively, and the solenoid valves 26a and 26b are provided as necessary.
Hot water was guided to the refrigerant heater 15 by opening and closing 6b.

In other words, during the heating cycle, hot water circulates through the exhaust heat recovery heat exchanger 18, 18, solenoid valve 26a1, refrigerant heater 15, and circulation pump 22 until the temperature rises to the set temperature, and when the hot water temperature exceeds the set temperature, the solenoid The valve 26 opens and the cold water from the radiator 19 side is mixed with the circulating hot water to control the temperature. Note that during the cooling cycle, the solenoid valve 26a is closed to allow hot water to circulate through the radiator 19.

(The problem that the invention is trying to solve) However,
The conventional system shown in FIG. 4 has the following drawbacks. In other words, when an overload condition occurs in the heating cycle, the discharge pressure increases in proportion to the engine speed, but if left unchecked, it is likely to be affected by gas injection and cause a high pressure cut phenomenon or engine breakdown. Easy to wake up.

On the other hand, even if the gas injection is simply shut off while the discharge pressure is rising, the remaining refrigerant and residual heat will often overshoot and cause a high-pressure cut phenomenon.

Note that even if gas injection is shut off from the beginning, the heating capacity will be significantly reduced, making it impossible to achieve the original purpose of improving capacity.

The present invention has been made in view of the above-mentioned problems, and its purpose is to enable an engine that continues to operate stably without high pressure cut or engine breakdown even under overload conditions during heating operation of a heat pump. An object of the present invention is to provide a drive type air conditioner.

[Structure of the Invention] (Means and Effects for Solving the Problems) In order to solve the above problems, the present invention provides an engine-driven air conditioner in which a compressor of a refrigeration cycle is driven by an engine to perform a heat pump. A refrigerant heater is installed to exchange heat between a hot water circuit that receives exhaust heat from the engine and an injection circuit, and a solenoid valve inserted in the hot water circuit and a solenoid valve inserted in the gas injection circuit are used to control the discharge pressure of the compressor. A two-step pressure switch is provided to detect and close each of the electromagnetic valves in a low pressure cut region, and a bypass pressure reducing device is connected in parallel to the injection electromagnetic valve.

(Example) The present invention will be described below based on the example shown in FIGS. 1 and 3. However, in FIG. 1, parts that are the same as those described in the "Prior Art" section above are given the same reference numerals, and their explanations are omitted, and different parts will be described in this section.

That is, in this embodiment, first, a three-way mixing valve 30 is interposed at the connection point between the outflow side of the hot water supply circuit 25 and the outflow side of the radiator 19.

Specifically, this three-way mixing valve 30 is made of heat-expandable wax. That is, as shown in FIG. 2, the three-way mixing valve 30 has an inlet/outlet (high-temperature water inlet) 33 and a water inlet (low-temperature water inlet) 34 formed on the lower side of the valve body 32 that are connected in series in the vertical direction. The hot and cold water passages 35 and water passages 36 are arranged alternately. Furthermore, a mixed water outlet 37 is provided at the upper stage of the valve body 32 and opens in a direction perpendicular to the direction in which the inlets 33 and 34 are lined up, and a passage portion 38 is formed in the center of the interior of the valve body 32 so that the mixed water Exit 37 and each hot water passage 35. It communicates with the water communication path 36. Then, wax (not shown) is placed inside the passage portion 38.
A structure is used in which a shaft-shaped Fuchs filling section 39 filled with Fuchs is installed along the vertical direction, and valves 40 and 41 provided between passages 35 and 36 are moved up and down. That is, in the three-way mixing valve 30, the opening degrees of the two valves of the hot water passage 35 and the water passage 36 are automatically adjusted in inverse proportion according to the temperature of the mixed water flowing around the outer periphery of the wax filling part 39 and flowing out to the outside. It has a structure.

The inlet/outlet 33 is placed on the outlet side of the hot water supply circuit 25, the water inlet 34 is placed on the outlet side of the radiator 19, and the mixed water outlet 37 is placed on the outlet side of the radiator 19.
are connected to the pump 22 side, and the entire three-way mixing valve 30 is provided at the connection point to automatically change the mixing ratio in response to the temperature on the outlet side so as to keep the mixed water temperature constant. Note that initially, the hot water passage 35 and the mixed water outlet 37 are in communication. Note that 42 is an adjustment dial provided at the upper part of the valve body 32 for adjusting the hot water temperature to a desired temperature.

On the other hand, the radiator 19 has a structure in which a part of the heat exchange surface further includes an independent heat exchange portion 19a.

The hot water piping 21 of the hot water closed circuit 23 is connected to the large-area heat exchange section 19b serving as the main body, as in FIG. 4. In addition, a branch pipe 21a branched from the hot water pipe 21 is connected to the inlet part of the divided heat exchange section 19b, and the outlet side is also connected to the outflow side (inlet/outlet 33 side) of the hot water supply circuit 25. Hot water piping 43 (equivalent to passage)
is connected to the radiator 19, and in order to stabilize the temperature of the hot water, a part of the hot water flowing out from the radiator 19 is always circulated (during both cooling and heating operations). Furthermore, as shown in FIG. 1, the gas injection solenoid valve 14 inserted in the injection circuit 16 is equipped with a capillary tube 5, for example, as a bypass pressure reducing device for releasing liquid.
0 are connected in parallel. Further, an accumulator 51 for removing liquid refrigerant is inserted in the middle of the injection circuit 16 located between the compressor 2 and the refrigerant heater 5, and this accumulator 51 stores and compresses the liquid refrigerant. This prevents liquid refrigerant from directly flowing into the machine 2.

Further, a pressure guide pipe 53a is connected to the discharge side of the compressor 2, and a two-step pressure switch 53 for detecting the discharge pressure of the compressor 2 is connected to the pressure guide pipe 53a. As shown in FIG. 3, this pressure switch 53 detects overload leading to engine stop, that is, the discharge pressure PH in the high pressure cut region.
The discharge pressure PL in the low cut region, which is the overload discharge pressure before reaching the discharge pressure PH, is detected. Each detection signal is then sent to the control section 54.

Further, the gas injection solenoid valve 14 and the hot water supply circuit solenoid valve 26a are connected to the control section 54, and the pressure switch 53 is set to the discharge pressure PL in the low cut range.
When it is detected, it is closed by a signal from the control section 54.

Next, the operation of the configuration of this embodiment will be explained. First, when this air conditioner performs cooling, the four-way valve 3 is switched to the cooling side, and the solenoid valve (flow path switching valve) 26a on the hot water pipe 24 is switched to "close" to compress the power of the gas engine 1. Transmit it to machine 2.

As a result, in the refrigerant circuit 44 surrounded by the two-dot chain line, the refrigerant is transferred to the compressor 2. Four-way valve 3. Outdoor heat exchanger4. Capillary tube for cooling 9. Indoor heat exchanger 11. The cooling cycle operation is performed by sequentially flowing to the four-way valve 6 and the suction side of the compressor 1 and circulating.

On the other hand, in the hot water circuit 17, the circulation pump 22 starts operating in conjunction with this operation. Note that the solenoid valve 2a is closed. The circulation pump 22 feeds the hot water in the hot water circuit 17, causing the hot water to flow through the heat recovery heat exchanger 18.
．． The exhaust heat of the gas engine 1 is recovered at the stage of passing through the gas engine 18. Then, this hot water is transferred to the branch pipe 21a and the heat exchange section 19a.

Hot water piping 43. Hot water input hole 33 of three-way mixing valve 30. Similarly, the mixed water flows sequentially through the mixed water outlet 37 and returns to the suction side of the circulation pump 22. Due to this circulation of hot water (engine cooling), the temperature of the hot water inside the pipes gradually rises. When the temperature of this hot water exceeds the set value, the wax in the three-way mixing valve 30 expands and contracts, causing the valve 40.
41 is raised, and low-temperature hot water (cooled by heat radiation) from the heat exchange section 19b is mixed into the hot water.

That is, due to the displacement of the wax, the opening degrees of the hot water inlet 33 and the water inlet 34 are controlled in inverse proportion. As a result, the mixing ratio changes in response to changes in temperature,
The hot water temperature is maintained constant. In other words, the automatic temperature adjustment function of the three-way mixing valve 30 ensures that the hot water is at an appropriate temperature (set value).
It is maintained. Even if a load fluctuation occurs, the automatic temperature adjustment function of the three-way mixing valve 30 follows it, so it can be seen that a stable temperature is maintained.

On the other hand, when performing heating, the four-way valve 3 is switched to the heating side and the gas injection solenoid valve 14 is opened. Furthermore, the electromagnetic valve (flow path switching valve) 26a is also switched to "open" to transmit the power of the gas engine 1 to the compressor 2.

As a result, in the refrigerant circuit 44, the refrigerant is supplied to the compressor 2, the four-way valve 3. Indoor heat exchanger 11. Expansion valve 6° outdoor heat exchanger 4. The air flows in sequence to the four-way valve 3 and the suction side of the compressor 1 to perform a circulating heating cycle operation. Also, at the same time,
The refrigerant that is diverted from the indoor heat exchanger 11 to the gas injection solenoid valve 14 flows into the refrigerant heater 15 through the gas injection solenoid valve 14 and the capillary tube 50, where it is heated (engine exhaust gas, which will be described later). due to heat). Furthermore, this heated refrigerant gas is injected into the cylinder of the compressor 2.

This increases heating capacity by utilizing engine exhaust heat. Note that the liquid component in the injected refrigerant is removed by an accumulator 51 on the way. Therefore, liquid compression in the compressor 1 can be prevented.

Also, during this heating operation, in the hot water circuit 17, the exhaust heat of the gas engine 1 is recovered through the heat recovery heat exchangers 18 and 18 using hot water flowing through the pipes, as in the previous cooling operation. This recovered hot water then flows through the solenoid valve 26.
a. Hot water input hole 33. of refrigerant heater 15° three-way mixing valve 30. Similarly, the mixed water flows sequentially through the mixed water outlet 37 and returns to the suction side of the circulation pump 22. Also, at this time, some of the hot water that has flowed into the branch pipe 21H flows through the heat exchange section 19a, the hot water pipe 43,
After joining the hot water flowing through the hot water pipe 24, the hot water inlet 33. The mixed water flows sequentially through the mixed water outlet 37 and returns to the circulation pump 22.

This supplies the refrigerant heater 15 with the exhaust heat of the gas engine 1 necessary to gasify the refrigerant.

As the hot water circulates, the temperature of the hot water in the pipe increases, and when the temperature exceeds the set value, the wax in the three-way mixing valve 30 expands and contracts, causing the valve 40. is raised, and the low-temperature hot water from the heat exchange section 19b is mixed into the hot water. As a result, the mixing ratio changes in response to changes in temperature, and the hot water temperature is maintained constant. In other words, the hot water is kept at an appropriate temperature (set value).

Here, even if load fluctuations occur, as in the case of cooling,
Since the automatic temperature adjustment function of the three-way mixing valve 30 follows load fluctuations, a stable temperature is maintained.

By the way, in the normal operating state during this heating operation, the discharge pressure of the compressor 1 is equal to the discharge pressure PL in the low cut region shown in FIG.
In the following pressure range, the gas injection solenoid valve 14 and the hot water supply circuit solenoid valve 26a are "open".
It becomes. However, when heating overload conditions occur,
The rotational speed of the gas engine 1 increases, and the discharge pressure Pd of the compressor 1 increases in proportion to this.

If left as is, high pressure cut or engine breakdown will occur. However, as shown in Figure 3, the engine speed is in the low rotation range (for example, 1000 to 15
00 rpm), the pressure switch 53 sets the discharge pressure PL in the low cut range (e.g. 23 kg/ci G).
is detected and this detection signal is sent to the control section 54. Control unit 5
When the valve 4 receives this signal, it sends a closing signal to the gas injection solenoid valve 14 and the hot water supply circuit solenoid valve 26a, thereby closing both of them. As a result, both the gas injection action and the hot water circulation action stop.
It is possible to suppress an increase in the discharge pressure Pd.

Incidentally, if only the gas injection solenoid valve 14 is closed when the discharge pressure increases, the hot water circulation action continues, and this heating action causes the cycle to overheat and the discharge pressure Pd to rise, which poses a risk of reaching the high cut pressure PH. . Further, when only the solenoid valve 26a for the hot water supply circuit is closed, a so-called liquid back phenomenon is likely to occur. Therefore, it is necessary to close the solenoid valves 14.26a at the same time.

On the other hand, even when both electromagnetic valves 14 and 26a are closed at the same time, there is residual heat in the refrigerant remaining in the injection circuit 16 and the hot water remaining in the hot water supply circuit 24. Then, due to this residual heat, the pressure may overshoot and reach the discharge pressure PH in the high pressure cut region. However, here, since the bypass capillary tube 50 is connected in parallel to the injection solenoid valve 14, the refrigerant is released through the capillary tube 50 even when the solenoid valve 14 is closed. Therefore, the fluid release prevents the cycle from overheating and high pressure cuts.
Continuation of operation can be ensured. Figure 3 shows the discharge pressure P of compressor 1.
d does not exceed the low cut range and the gas engine 1 operates within a safe discharge pressure range even if the rotation speed of the gas engine 1 exceeds the low rotation range (for example, 1500 rpm or more).

Note that the present invention is not limited to the above embodiments. For example, the pressure switch may be of any mechanical or electrical type.

[Effects of the Invention] As described above, according to the present invention, even under overload conditions during operation of heat pump heating, stable pressure control can be obtained without easily cutting off high pressure.

In addition, stable operation can be continued without engine breakdown due to large load fluctuations.

Furthermore, in order to stabilize the cycle, liquid is released through the bypass cavity during overload, preventing overheating and reducing pressure. Since the discharge pressure can be suppressed within a certain range, even compressors using mechanical seals can be used safely. In other words, it leads to an expansion of the range of use.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an engine-driven air conditioner according to an embodiment of the present invention, and FIG. 2(a) is a block diagram showing an engine-driven air conditioning apparatus. (b) is a side sectional view and a half sectional view showing the structure of a three-way mixing valve according to the same example, FIG. 3 is a characteristic diagram of the compressor according to the example, and FIG. FIG. 2 is a configuration diagram showing the engine-driven air conditioner used. 1... Gas engine, 2... Compressor, 3... Four-way valve, 4... Outdoor heat exchanger, 6... Expansion valve, cooling capillary tube, indoor heat exchanger (refrigeration) cycle equipment), 14... solenoid valve for gas injection, 15
... Refrigerant heater, 18 ... Heat exchanger for exhaust heat recovery, 1
9...Radiator, 23...Hot water closed circuit, 25...
- Hot water supply circuit, 26a... Solenoid valve, 50... Capillary tube, 53... Pressure switch, 54...
control section. Applicant's agent Patent attorney Atsushi Tsuboi (a) (b) Figure 2 Figure 3

Claims (1)

[Claims] An engine equipped with an exhaust heat recovery heat exchanger, a heat pump refrigeration cycle formed by sequentially connecting refrigeration cycle equipment to a compressor driven by the engine, the exhaust heat recovery heat exchanger, a circulation pump, and a refrigerant. A hot water supply circuit connected to a heating machine to form a closed circuit, a hot water solenoid valve inserted in the middle of this hot water supply circuit, and a discharge port of the indoor heat exchanger of the heat pump refrigeration cycle. an injection circuit connecting the side and the inlet side of the compressor via the refrigerant heater, a gas injection solenoid valve inserted in the middle of this injection circuit, and a gas injection solenoid valve connected in parallel to the gas injection solenoid valve. A connected pressure reducing device, a two-step pressure switch that detects the discharge pressure of the high-pressure cut of the discharge pressure of the compressor and the discharge pressure of the low-pressure cut before this, and this pressure switch detects the discharge pressure of the low-pressure cut region. A drive type air conditioner comprising: a control section that sends a closing signal to the hot water solenoid valve and the gas injection solenoid valve when detected.