CN1584449A - Air-cooled hot pumping hot air cold water set driven by gas engine - Google Patents

Abstract

The air-cooled heat pump type cold and hot water unit driven by a gas engine is composed of a gas engine engine, a set of vapor compression heat pump system, and a gas engine cooling and waste heat recovery system, mainly including a gas engine, a compressor, and a four-way valve , plate heat exchanger, expansion valve, finned tube heat exchanger, water-water heat exchanger, cooling water valve group, bypass solenoid valve, water-refrigerant heat exchanger, the waste heat utilization of the engine is through the gas engine The water-refrigerant heat exchanger and the water-water heat exchanger arranged between the heat pump part and the heat pump part are realized. The present invention also designs a cooling water flow control valve group. According to different application occasions, different climate environments and different working conditions of the gas engine heat pump, the controller of the valve group controls the cooling water valve group to switch the engine correctly. Flow direction of cooling water, reasonable distribution and utilization of waste heat of gas engine. Realize the effective utilization of energy, and have remarkable energy-saving effect.

Description

Air-cooled heat pump type chiller and hot water unit driven by gas engine

technical field

The invention relates to an air-cooled heat pump type cold and hot water unit, in particular to a gas engine-driven air-cooled heat pump type heat pump driven by a gas engine that drives a vapor compression heat pump cycle and can provide cold and hot water for air conditioning. A water unit belongs to the technical field of refrigeration and air conditioning.

Background technique

With the rapid development of my country's economy, air conditioners in urban buildings are becoming more and more popular. Air-cooled heat pump type cold and hot water units, as a cold and heat source device that is easy to install and can provide cold and hot water for air conditioning, occupy an increasing proportion of air-conditioning equipment in urban buildings in my country. At present, air-cooled heat pump chillers and hot water units are generally driven by electric motors. The use of a large number of air-cooled heat pump chillers and other air-conditioning equipment makes the consumption of power resources in heating and heating seasons continue to increase, and the peak-to-valley difference in power is becoming increasingly serious. .

The vapor compression heat pump unit driven by a gas engine instead of an electric motor has many advantages: (1) Non-electric resources such as natural gas, city gas, and petroleum gas can be used as the energy source of the unit, thus reducing the consumption of electric resources by the air conditioning system and alleviating the power consumption. (2) The engine waste heat can be recovered during the heating process, and the system has a high energy utilization rate; (3) The gas engine can realize variable speed adjustment, and the part-load performance of the heat pump system is better. However, in the design of gas engine heat pumps, how to rationally utilize the waste heat of the engine in the heat pump system and design a gas engine heat pump with high energy efficiency according to the climatic conditions in different regions is an important issue in the design of gas engine driven heat pumps.

In the prior art, there is a kind of "one drags many" gas heat pump type air conditioner (patent application number: 02130144.1 and 02105515.7) with an outdoor unit equipped with multiple indoor units. It uses refrigerant-air direct heat exchange (referred to here as "refrigerant gas engine heat pump") to achieve the purpose of cooling and heating. The "refrigerant type gas engine heat pump" is characterized in that a refrigerant-water heat exchanger is connected in parallel on the side of the outdoor finned tube heat exchanger, through which the waste heat recovered from the engine is released to the low pressure heat pump system The side refrigerant bears part of the load of the evaporator, increases the evaporation temperature of the heat pump in cold regions, and improves the efficiency of the heat pump. For areas where the outdoor temperature is relatively mild in winter, the use of "refrigerant gas engine heat pump" can indeed increase the evaporation temperature of the heat pump, thereby increasing the heating coefficient of the heat pump. But at the same time, the "refrigerant gas engine heat pump" also reduces the absorption of renewable heat from the environment. That is to say, the "refrigerant gas engine heat pump" replaces the heat that could have been absorbed from the air with the waste heat of the engine. Especially when the use of waste heat causes the evaporation temperature to be higher than the ambient temperature, the finned tube evaporator can no longer absorb heat from the outdoor air, so it cannot fully utilize the characteristics of the heat pump that can use low-grade heat sources. In addition, the "refrigerant type gas engine heat pump" uses refrigerant as the cold and heat transmission medium, so the range of cold and heat transmission is limited, the capacity of the unit should not be too large, and the system piping design must fully consider the oil return of the compressor and the cooling capacity. Distribution and other technical issues, high initial investment in equipment, and difficult installation.

Contents of the invention

In order to make up for the deficiencies of the existing technology and expand the application range of the gas engine-driven heat pump, the air-cooled heat pump type cold and hot water unit driven by the gas engine is designed. The unit consists of a gas engine, a vapor compression heat pump system, and a gas engine cooling and waste heat recovery system. The power transmission between the engine and the heat pump system is realized through the direct connection of the clutch and the rotating shaft, while the waste heat utilization of the engine is realized through a water-water heat exchanger and a water-refrigerant heat exchanger.

The main feature of the present invention is that a water-refrigerant heat exchanger and a water-water heat exchanger are arranged between the gas engine part and the heat pump part, and a cooling water flow control valve group is designed, which can be controlled according to the cold and hot water unit In different applications, different climate environments, and different unit working conditions, through the control program of the valve group, the flow direction of the engine cooling water can be correctly switched, and the waste heat of the gas engine can be reasonably distributed and utilized. For example, when the unit is working at a lower ambient temperature (the finned tube heat exchanger of the heat pump is frosted), and the heating coefficient of the heat pump itself is very low, switch the engine cooling water to the water-refrigerant heat exchanger to utilize the waste heat of the engine Bear part of the load of the evaporator, thereby improving the heating capacity of the heat pump chiller and hot water unit; when the unit works in a general low temperature environment, switch the engine cooling water to the water-water heat exchanger, so that the heat pump unit can fully absorb the heat in the air, And the waste heat of the engine is directly supplied to the hot water of the air conditioner; when the unit is in the cooling condition, in order to ensure the normal operation of the engine, the waste heat of the engine is released to the environment through the unit fan. In addition, in order to avoid the engine cooling water inlet temperature being too low, a bypass circuit is set in the cooling water valve group to fully ensure the normal operation of the engine.

The invention can rationally utilize the waste heat of the gas engine, realize the effective utilization of energy, and has remarkable energy-saving effect.

Description of drawings

Fig. 1 is the structural schematic diagram of the air-cooled heat pump type cold and hot water unit driven by the gas engine of the present invention

Figure 2 is a schematic diagram of the flow direction switching control structure of the cooling water valve group of the present invention

Fig. 3 is a schematic diagram of the first embodiment of the present invention when the unit is in heating operation

Fig. 4 is a schematic diagram of the second embodiment of the unit heating operation of the present invention

Fig. 5 is a schematic diagram of the embodiment of the present invention when the unit is in cooling operation

In the figure, 1 is a gas engine, 2 is a clutch, 3 is a compressor, 4 is a gas-liquid separator, 5 is a four-way valve, 6 is a plate heat exchanger, 7 is A check valve, 8 is B check valve , 9 is C one-way valve, 10 is D one-way valve, 11 is A stop valve, 12 is B stop valve, 13 is expansion valve, 14 is sight glass, 15 is filter, 16 is liquid reservoir, 17 is Fan, 18 is a finned tube heat exchanger, 19 is a radiator, 20 is a water-refrigerant heat exchanger, 21 is a bypass solenoid valve, 22 is a cooling water valve group, 23 is a water-water heat exchanger, 24 is the flue gas heat exchanger, 25 is the cooling water pump, 26 is the gas pressure reducing valve, and 27 is the valve group controller

In the figure, the flow direction of the fluid in the pipeline is indicated by the direction of the arrow. The thick solid line represents the refrigerant cycle, the thin solid line represents the cold and hot water cycle of the air conditioner, and the dotted line represents the engine cooling water cycle.

Detailed ways

The specific embodiments of the present invention will be further described below in conjunction with the accompanying drawings.

As shown in Fig. 1 and Fig. 2, the present invention includes gas engine 1, clutch 2, compressor 3, gas-liquid separator 4, four-way valve 5, plate heat exchanger 6, A check valve 7, B check valve 8. C one-way valve 9, D one-way valve 10, A stop valve 11, B stop valve 12, expansion valve 13, mirror 14, filter 15, liquid reservoir 16, fan 17, fin tube heat exchanger 18. Radiator 19, water-refrigerant heat exchanger 20, bypass solenoid valve 21, cooling water valve group 22, water-water heat exchanger 23, flue gas heat exchanger 24, cooling water pump 25, gas pressure reducing valve 26. Valve group controller 27.

The cold and hot water unit of the present invention can be divided into two parts: the gas engine part and the heat pump system part, and the heat exchange between the gas engine part and the heat pump part is realized by the water-refrigerant heat exchanger 20 and the water-water 23 heat exchanger, The flow direction of the gas engine cooling water is switched by the cooling water valve group 22 controlled by the valve group controller 27 .

In the part of the heat pump system, the outlet of the compressor 3 is connected to the inlet (D pipe) of the four-way valve 5, and the E pipe of the four-way valve 5 is connected to one end of the refrigerant channel of the plate heat exchanger 6, and the plate heat exchanger 6 The other end of the refrigerant passage is connected to the outlet of check valve A 7 and the inlet of check valve D 10, the outlet of check valve B 8 and the inlet of check valve C 9 are connected to the finned tube One end of the refrigerant flow channel of the heat exchanger 18 is connected, the other end of the refrigerant flow channel of the finned tube heat exchanger 18 is connected with one end of the refrigerant flow channel of the water-refrigerant heat exchanger 20, and the water-refrigerant heat exchanger 20 The other end of the refrigerant passage is connected to the C pipe of the four-way valve 5 . A bypass solenoid valve 21 is connected to the inlet and outlet ports of the refrigerant passage of the water-refrigerant heat exchanger 20 . The outlet of the four-way valve 5 (S pipe) is connected with the inlet of the gas-liquid separator 4, and the outlet of the gas-liquid separator 4 is connected with the inlet of the compressor 3. The outlets of C one-way valve 9 and D one-way valve 10 are connected to the inlet of liquid reservoir 16, and the outlet of liquid reservoir 16 passes through A cut-off valve 11, filter 15, sight glass 14, and is connected with expansion valve 13 Then through the B cut-off valve 12, it is connected with the inlets of the A check valve 7 and the B check valve 8. In the air-conditioning water circulation loop, the return pipe of the air-conditioning system is connected to the inlet of the air-conditioning water channel of the plate heat exchanger 6, and the outlet of the air-conditioning water channel of the plate heat exchanger 6 is connected to the inlet of the air-conditioning water channel of the water-water heat exchanger 23 , the outlet of the air-conditioning water channel of the water-water heat exchanger 23 is connected with the water inlet pipe of the air-conditioning system.

In the engine system part, the cooling water outlet of the engine is connected with the inlet of the cooling water channel of the flue gas heat exchanger 24, and the outlet of the cooling water channel of the flue gas heat exchanger 24 is connected with the a end of the cooling water valve group 22, The b-end, c-end and d-end of the cooling water valve group 22 are respectively connected with the inlet of the engine cooling water passage of the water-water heat exchanger 23, the inlet of the engine cooling water passage of the water-refrigerant heat exchanger 20, and the inlet of the radiator 19 . The outlet of the engine cooling water passage of the water-refrigerant heat exchanger 20, the outlet of the engine cooling water passage of the water-water heat exchanger 23, the outlet of the radiator 19 and the e end of the cooling water valve group 22 are all connected to the engine cooling water pump 25 The imports are connected. The outlet of the engine cooling water pump 25 is connected to the cooling water inlet of the gas engine 1 . The gas engine 1 is connected with the flue inlet of the flue gas heat exchanger 24 through the exhaust flue. The fan 17 is installed above the radiator 19 and the finned tube heat exchanger 18, and is used for heat dissipation of the cooling water of the gas engine 1 and heat exchange between the refrigerant and the air.

The gas engine 1 and the compressor 3 are shaft-connected via a clutch 2 . The fuel supply pipe is connected to the fuel inlet of the gas engine 1 through a pressure reducing valve 26 . The three input ends of the valve group controller 27 are electrically connected to the output ends of the outdoor temperature sensor, the finned tube outlet air temperature sensor and the engine inlet water temperature sensor respectively, and the other input end is electrically connected to the cooling and heating operation mode switching switch. The three output ports of the valve group controller 27 are respectively connected to the control ports of the three solenoid valves inside the cooling water valve group 22 , and the other output port is connected to the control port of the bypass solenoid valve 21 .

The unit of the present invention has two implementation modes during heating operation.

The first embodiment of heating operation

As shown in FIG. 3 , the first embodiment of the heating operation of the chiller and hot water unit of the present invention occurs outdoors in a generally low-temperature environment. In this heating mode, the four-way valve 5 is switched to the heating mode, so that the gas discharged from the compressor 3 releases heat in the plate heat exchanger 6, and the refrigerant flows out of the plate heat exchanger 6 and passes through the liquid accumulator. 16. Filter 15, sight glass 14, and expansion valve 13 enter the finned tube heat exchanger 18 to absorb air heat. Because in this heating operation mode, the water in the engine cooling water channel in the water-refrigerant heat exchanger 20 is in a static state, in order to prevent the water in the heat exchanger from freezing, the refrigerant flow in the finned tube heat exchanger 18 A bypass solenoid valve 21 capable of bidirectional flow is arranged at both ends of the channel, so that the refrigerant returns to the C pipe of the four-way valve 5 through the bypass solenoid valve.

In the engine cooling water circuit, the three-way valve inside the cooling water valve group 22 is controlled by the valve group controller 27, so that the a end and the b end are connected. At this time, the cooling water heated by the cylinder liner of the gas engine 1 and the flue gas heat exchanger 24 goes to the water-water heat exchanger 23 to release the heat to the air-conditioning water and then returns to the gas engine 1 to realize the waste heat of the gas engine 1 use.

Second embodiment of heating operation

As shown in Fig. 4, the second embodiment of the heating operation of the chiller and hot water unit of the present invention occurs in an outdoor environment with a relatively low ambient temperature. Due to the frequent frosting of air source heat pumps at low temperatures, the coefficient of performance of the heat pump unit will drop sharply, and it may even fail to heat. In order to ensure that the unit can still heat at low temperature, this implementation method can be adopted.

In this embodiment, the refrigerant circulation mode of the heat pump system is basically the same as that of the first embodiment in heating operation. The difference from the first embodiment is that, at such a low outdoor ambient temperature, the bypass solenoid valve 21 is controlled by the valve group controller 27 to close, and the refrigerant flows through the water-refrigerant heat exchanger 20 and then passes through the The four-way valve 5 and the gas-liquid separator 4 return to the compressor 3 .

In the engine cooling water circuit, the three-way valve inside the cooling water valve group 22 is switched by the valve group controller 27, so that the a end and the c end are connected. At this time, the flue gas heat exchanger 24 and the water-refrigerant heat exchanger 20 are connected, so that the gas engine 1 , the flue gas heat exchanger 24 and the water-refrigerant heat exchanger 20 form a circuit. The cooling water heated by the cylinder liner of the gas engine 1 flows out from the cylinder liner of the gas engine 1, enters the flue gas heat exchanger 24 to be heated again, and then releases heat to the low-pressure refrigerant through the water-refrigerant heat exchanger 20 and returns to The gas engine 1 realizes waste heat utilization.

Implementation of cooling operation

As shown in Figure 5, the embodiment of the cooling operation of the cold and hot water unit of the present invention is to switch the four-way valve to the cooling mode, so that the exhaust port of the compressor 3 is connected to the finned tube heat exchanger 18, and the high temperature After the high-pressure refrigerant releases heat to the environment through the finned tube heat exchanger 18, it passes through the liquid receiver 16, the filter 15, the mirror 14, and the expansion valve 13, and then enters the plate heat exchanger 6 to absorb heat, and then passes through the four-way valve 5, The gas-liquid separator 4 returns to the compressor 3 . In order to prevent the stationary cooling water in the cooling water channel of the water-refrigerant heat exchanger 20 from being heated by the high-temperature and high-pressure refrigerant discharged from the compressor, resulting in the generation of water vapor, the bypass solenoid valve 21 is opened by the valve group controller 27, so that The refrigerant at the outlet of the compressor 1 is bypassed to the finned tube heat exchanger 18 . Under refrigeration conditions, due to the effect of pressure difference, the A check valve and C check valve connected between the plate heat exchanger 6 and the finned tube heat exchanger 18 conduct, and the B check valve and D check valve The valve is blocked, which can ensure that the refrigerant always passes through the expansion valve 13 from the same direction.

In the cooling operation, in order to ensure the normal operation of the engine and avoid the accumulated water in the flue gas heat exchanger 24 from being heated to boiling during the cooling operation. Connect an engine waste heat radiator 19 in the system. The radiator 19 is connected with the e end of the cooling water valve group 22 and the cooling water inlet port of the gas engine 1, and forms a heat dissipation circuit with the engine 1 and the flue gas heat exchanger 24, and releases heat by exchanging heat with the outdoor air. Get rid of the waste heat of the gas engine 1.

Structural principle of valve group control

As shown in FIG. 2 , the input signals of the valve group controller 27 are the outdoor temperature, the outlet temperature of the finned tube heat exchanger, the inlet water temperature of the engine, and the working mode of the unit. The specific implementation process is as follows: the unit first determines whether the unit is in the heating or cooling mode according to the working mode of the system. When it is in the heating mode, the cooling water valve group 22 connects the two ends of a and b or the two ends of a and c; When the unit is in cooling mode, the cooling water valve group 22 connects both ends of a and d. In the heating mode, firstly, the cooling water valve group 22 connects both ends of a and b to add residual heat to the air-conditioning water. During operation, judging from the outdoor temperature and the outlet temperature of the finned tube 18, if the outlet temperature of the finned tube heat exchanger is too low, connect the two ends of a and c of the cooling water valve group 22, so that the residual heat of the engine bears the finned heat. Part of the heat of the tube evaporator 18, if the outlet temperature of the finned tube heat exchanger 18 is not very low, the two ends of a and b of the cooling water valve group 22 are connected to add waste heat to the air-conditioning water. When the outdoor temperature is very low, and the units a and c of the cooling water valve group 22 are connected and the unit is still in the frosting state, the ports a and b of the cooling water valve group 22 are connected, and the four-way valve is switched so that The heat pump unit itself is in defrosting operation.

Regardless of the working mode, in order to ensure the normal and efficient operation of the engine, the temperature of the cooling water entering the engine cannot be lower than 80°C. The cooling water at the outlet of the flue gas heat exchanger 24 is bypassed back to the engine, and when the engine inlet water temperature rises to 85°C, the cooling water valve group 22 is switched to the corresponding waste heat recovery or heat dissipation position through the valve group controller 27 .

The bypass solenoid valve 21 is closed only when the two ends a and c of the cooling water valve group 22 are connected. In other cases, the valve is always open. The switching control mode of the engine cooling water valve group 22 ensures that the unit always operates in an efficient and safe mode.

Claims (4)

1. An air-cooled heat pump type cold and hot water unit driven by a gas engine, comprising a gas engine (1), a clutch (2), a compressor (3), a gas-liquid separator (4), a four-way valve (5), Plate heat exchanger (6), A check valve (7), B check valve (8), C check valve (9), D check valve (10), A stop valve (11), B stop valve (12), expansion valve (13), sight glass (14), filter (15), liquid reservoir (16), fan (17), finned tube heat exchanger (18), radiator (19), The flue gas heat exchanger (24), the cooling water pump (25), the gas pressure reducing valve (26), are characterized in that it also includes a water-refrigerant heat exchanger (20), a bypass solenoid valve (21), a valve group ( 22), water-water heat exchanger (23), valve group controller (27), the heat exchange of the gas engine part and the heat pump part passes through the water-refrigerant heat exchanger (20) and the water-water heat exchanger (23 ) to realize that the cooling water flow of the gas engine (1) is switched through the cooling water valve group (22) controlled by the valve group controller (27). 2. The gas engine-driven air-cooled heat pump type chiller and hot water unit according to claim (1), characterized in that in the heat pump part, the outlet of the compressor (3) and the inlet (D pipe) of the four-way valve (5) ), the E pipe of the four-way valve (5) is connected to one end of the refrigerant flow path of the plate heat exchanger (6), and the other end of the refrigerant flow path of the plate heat exchanger (6) is connected to the A check valve ( 7) and the inlet of the D check valve (10) are connected, the outlet of the B check valve (8) and the inlet of the C check valve (9) are both connected to the finned tube heat exchanger (18) for cooling One end of the refrigerant flow channel is connected, the other end of the refrigerant flow channel of the finned tube heat exchanger (18) is connected with one end of the refrigerant flow channel of the water-refrigerant heat exchanger (20), and the water-refrigerant heat exchanger (20) The other end of the refrigerant passage is connected to the C pipe of the four-way valve (5), and a bypass solenoid valve (21) is connected to the inlet and outlet ports of the refrigerant passage of the water-refrigerant heat exchanger (20). ), the outlet (S pipe) of the four-way valve (5) is connected with the inlet of the gas-liquid separator (4), the outlet of the gas-liquid separator (4) is connected with the inlet of the compressor (3), and the C check valve The outlets of (9) and D one-way valves (10) are all connected to the inlet of the liquid reservoir (16), and the outlet of the liquid reservoir (16) passes through the A cut-off valve (11), the filter (15), the sight glass (14), connected with the expansion valve (13) and then connected to the inlets of the A check valve (7) and the B check valve (8) through the B cut-off valve (12), in the air-conditioning water circulation loop, the air-conditioning system The return pipe is connected with the inlet of the air-conditioning water channel of the plate heat exchanger (6), the outlet of the air-conditioning water channel of the plate heat exchanger (6) is connected with the inlet of the air-conditioning water channel of the water-water heat exchanger (23), and the water- The outlet of the air-conditioning water channel of the water heat exchanger (23) is connected with the water inlet pipe of the air-conditioning system. 3. The air-cooled heat pump type cold and hot water unit driven by a gas engine according to claim 1, characterized in that in the gas engine system part, the cooling water outlet of the gas engine (1) is the same as the flue gas heat exchanger (24) The inlet of the cooling water channel is connected, the outlet of the cooling water channel of the flue gas heat exchanger (24) is connected with the a end of the cooling water valve group (22), the b end, the c end of the cooling water valve group (22) and The d end is respectively connected with the inlet of water-water heat exchanger (23) engine cooling water passage, the inlet of engine cooling water passage of water-refrigerant heat exchanger (20) and the inlet of radiator (19). The outlet of the engine cooling water passage of the heater (20), the outlet of the engine cooling water passage of the water-water heat exchanger (23), the outlet of the radiator (19) and the e end of the cooling water valve group (22) are all connected to the engine The inlet of the cooling water pump (25) is connected, the outlet of the engine cooling water pump (25) is connected with the cooling water inlet of the gas engine (1), and the gas engine (1) is connected to the flue gas heat exchanger (24) through the exhaust flue. The flue inlets are connected, the fan (17) is installed above the radiator (19) and the finned tube heat exchanger (18), the gas engine (1) and the compressor (3) are shaft-connected through the clutch (2), The fuel supply pipe is connected with the fuel inlet of the gas engine (1) through a pressure reducing valve (26). 4. The air-cooled heat pump type cold and hot water unit driven by a gas engine according to claim 1, characterized in that the three input ends of the valve group controller (27) are connected with the outdoor temperature sensor and the finned tube outlet air temperature sensor respectively. It is electrically connected to the output end of the engine inlet water temperature sensor, and the other input end is electrically connected to the hot and cold operation mode switch. The three output ends of the valve group controller (27) are respectively connected to the three solenoid valves inside the cooling water valve group (22). The control end of the valve is connected, and the other output end is connected with the control end of the bypass solenoid valve (21).

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