Air source heat pump system with host multi-stage regulation and circulating water variable flow

Abstract

The utility model belongs to water ring heat pump technical field. The purpose is to provide a kind of host multi-stage regulation and circulating water variable flow air source heat pump system, and its heat pump unit operation energy efficiency is high, and energy-saving effect is good. Adopt following technical scheme, including first host system and second host system, first host system includes first water pump group and first heat pump group, and second host system includes second water pump group and second heat pump group;Multiple water pumps in first water pump group and second water pump group are all parallelly connected, and multiple heat pumps in first heat pump group and second heat pump group are all parallelly connected;First host system and second host system are parallelly connected, and the water inlet line of first host system and second host system is all communicated with total water inlet line, and the water outlet line of first host system and second host system is all communicated with total backwater line;Multiple water pumps in first water pump group and second water pump group are all for the same lift, and different flow. The utility model is used for air conditioning system, and energy-saving effect is good.

Description

Technical Field

[0001] This utility model relates to an air source heat pump system with multi-stage main unit adjustment and variable flow rate of circulating water, belonging to the field of water loop heat pump technology. Background Technology

[0002] A water-loop heat pump air conditioning system is an application of air-source heat pump units. It uses a water loop to connect multiple air-source heat pump units in parallel to form a closed loop, thus creating a heat pump heating and cooling air conditioning system that recovers waste heat from inside the building as its low-grade heat source.

[0003] Figure 2 From National Building Standard Design Atlas 06K504, Design and Installation of Water-Ring Heat Pump Air Conditioning Systems, such as Figure 2 As shown, in existing water-loop heat pump systems, regardless of the number of air-source heat pump units, it is all a single water-loop system. The water pumps in the water-loop system are either in operation with one on standby or two on operation with one on standby. This presents the following problems and drawbacks.

[0004] 1. The water pump's energy consumption is fixed, with no unnecessary high energy consumption. In a water circulation system, the pump's head must meet the water supply requirements of the most unfavorable end, which is a fixed value; the flow rate must meet the unit's requirements, also a fixed value. These fixed head and flow rate requirements ensure that the pump's operating power is constant. When end-user demand decreases, excess circulating water returns to the return pipe through the differential pressure bypass valve between the supply and return main pipes to meet the unit's flow rate requirements. The pump's power output cannot decrease based on a reduction in end-user demand.

[0005] 2. High-efficiency operation of air source heat pump units cannot be guaranteed at all times. Air source heat pumps are divided into variable frequency units and fixed frequency units. Variable frequency units operate at a high efficiency range of 30%-70% load. Load rates that are too low or too high will cause the unit to deviate from its high-efficiency operating range, resulting in reduced energy efficiency. Fixed frequency units operate at their highest efficiency range at 100% load. Below 30% load, the unit needs to start frequently, resulting in additional energy loss (start-stop losses can reach 15-30%, and the energy consumption of one start-stop operation is approximately equivalent to 3-5 minutes of full-load operation).

[0006] In actual use, the demand at indoor terminals is constantly changing. For example, during the heating season, the indoor heat demand increases or decreases in tandem with the ambient temperature, which fluctuates accordingly. Ambient temperature also varies at different times of the day, causing the heating and cooling demands at indoor terminals to increase or decrease accordingly. Furthermore, the heating and cooling demands of residential buildings, office buildings, and shopping malls with different uses also increase or decrease due to the concentrated flow of people. The fixed operating mode of the generating units causes the unit's operating load rate to deviate from the high-efficiency operating range during many periods, resulting in the unit's operating energy efficiency being lower than the rated energy efficiency and the system's energy efficiency being reduced. Utility Model Content

[0007] In view of the shortcomings of the existing technology, the purpose of this utility model is to provide an air source heat pump system with high operating energy efficiency and good energy-saving effect, featuring multi-stage main unit adjustment and variable flow rate of circulating water.

[0008] To achieve the above objectives, the present invention adopts the following technical solution: an air source heat pump system with multi-stage main unit adjustment and variable flow rate of circulating water, comprising a first main unit system and a second main unit system, wherein the first main unit system comprises a first water pump group and a first heat pump group, and the second main unit system comprises a second water pump group and a second heat pump group. Multiple water pumps in the first water pump group and the second water pump group are connected in parallel, and multiple heat pumps in the first heat pump group and the second heat pump group are connected in parallel. The first water pump group and the first heat pump group are connected through pipelines, and the second water pump group and the second heat pump group are connected through pipelines. The first host system and the second host system are connected in parallel. The water inlet pipes of the first host system and the second host system are both connected to the main water inlet pipe, and the water outlet pipes of the first host system and the second host system are both connected to the main return water pipe. The pumps in the first pump group have the same head but different flow rates. The pump with the smallest flow rate is the one that can meet the flow rate requirement when starting up at least one heat pump in the first heat pump group, and the pump with the largest flow rate is the one that can meet the flow rate requirement when starting up all heat pumps in the first heat pump group. The pumps in the second pump group have the same head but different flow rates. The pump with the smallest flow rate is the one that can meet the flow rate requirement when starting up at least one heat pump in the second heat pump group, and the pump with the largest flow rate is the one that can meet the flow rate requirement when starting up all heat pumps in the second heat pump group.

[0009] Preferably, the number of heat pumps in both the first heat pump group and the second heat pump group is five. The first water pump set includes: The first water pump whose flow rate meets the flow rate requirements of both heat pumps when starting up; The second water pump has a flow rate that meets the startup requirements of the three heat pumps. The third water pump has a flow rate that meets the startup requirements of the five heat pumps; The second water pump set includes: The fourth water pump has a flow rate that meets the startup flow requirements of the four heat pumps. The fifth water pump has a flow rate that meets the startup flow requirements of the five heat pumps.

[0010] Preferably, multiple sensors are installed on both the main inlet pipe and the main return pipe, including a temperature sensor and a differential pressure sensor.

[0011] Preferably, each heat pump in the first heat pump group and the second heat pump group is equipped with an inlet valve on its inlet pipe and an outlet valve on its outlet pipe.

[0012] Preferably, a constant pressure water supply pipeline is connected to the main water inlet pipeline.

[0013] Preferably, the present invention also includes a control system, which is connected to the start / stop switches of all water pumps, the start / stop switches of all heat pumps, the inlet and outlet valves of all heat pumps, and all sensors.

[0014] Preferably, all heat pumps in the first and second heat pump groups are air source heat pumps.

[0015] Compared with the prior art, the present invention has the following beneficial effects.

[0016] 1. This utility model is designed with two main systems. When working, it can be guided by the dynamic demand of the terminal. The cooling / heating of the heat pump unit changes dynamically with the terminal demand, and the water pump output also switches synchronously. Furthermore, by starting and stopping some heat pump units, the heat pump units can maintain a high-efficiency operating state throughout the entire operation process. The water pumps are combined in large, medium and small sizes to adapt to high-efficiency operation.

[0017] 2. The energy-saving effect of this utility model is very obvious. The comprehensive energy consumption of the fixed frequency heat pump unit can be reduced by more than 35%; the comprehensive energy consumption of the variable frequency heat pump unit can be reduced by more than 25%. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 This is a schematic diagram of the present invention.

[0020] Figure 2 This is a schematic diagram of an existing water-loop heat pump system.

[0021] Figure 3 This is a graph showing the relationship between the load factor and COP of an air source heat pump unit.

[0022] In the diagram: 1 is the first main unit system, 11 is the first water pump group, 111 is the first water pump, 112 is the second water pump, 113 is the third water pump, 12 is the first heat pump group, 2 is the second main unit system, 21 is the second water pump group, 211 is the fourth water pump, 212 is the fifth water pump, 22 is the second heat pump group, 3 is the main water inlet pipe, 4 is the main water return pipe, 5 is the sensor, 6 is the constant pressure water supply pipe, and 7 is the control system. Detailed Implementation

[0023] The technical solutions of the present utility model will be clearly and completely described in conjunction with the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other implementation methods obtained by those skilled in the art without creative effort are within the scope of protection of the present utility model.

[0024] It should be noted that the structures, proportions, sizes, etc. shown in the accompanying drawings of this specification are only used to complement the content disclosed in the specification for those skilled in the art to understand and read, and are not intended to limit the conditions under which this utility model can be implemented. Therefore, they have no substantial technical significance. Any modification to the structure, change in the proportional relationship, or adjustment of the size should still fall within the scope of the technical content disclosed in this utility model, provided that it does not affect the effects and purposes that this utility model can produce. It should be noted that in this specification, relational terms such as "first" and "second" are only used to distinguish one entity from several other entities, and do not necessarily require or imply any such actual relationship or order between these entities.

[0025] The present invention provides the following embodiments.

[0026] like Figure 1 As shown, the present invention provides an air source heat pump system with multi-stage main unit adjustment and variable flow rate of circulating water, including a first main unit system 1 and a second main unit system 2. The first main unit system 1 includes a first water pump group 11 and a first heat pump group 12, and the second main unit system 2 includes a second water pump group 21 and a second heat pump group 22. Multiple water pumps in the first water pump group 11 and the second water pump group 21 are connected in parallel, and multiple heat pumps in the first heat pump group 12 and the second heat pump group 22 are connected in parallel. The first water pump group 11 and the first heat pump group 12 are connected through pipelines, and the second water pump group 21 and the second heat pump group 22 are connected through pipelines. The first host system 1 and the second host system 2 are connected in parallel. The water inlet pipes of the first host system 1 and the second host system 2 are both connected to the main water inlet pipe 3, and the water outlet pipes of the first host system 1 and the second host system 2 are both connected to the main return water pipe 4. The pumps in the first pump group 11 have the same head but different flow rates. The pump with the smallest flow rate is the one that can meet the flow rate requirement when starting up at least one heat pump in the first heat pump group 12, and the pump with the largest flow rate is the one that can meet the flow rate requirement when starting up all heat pumps in the first heat pump group 12. The pumps in the second pump group 21 have the same head but different flow rates. The pump with the smallest flow rate is the one that can meet the flow rate requirement when starting up at least one heat pump in the second heat pump group 22, and the pump with the largest flow rate is the one that can meet the flow rate requirement when starting up all heat pumps in the second heat pump group 22.

[0027] In this utility model, the number of heat pumps in the first heat pump group 12 and the second heat pump group 22 is preferably five. The first water pump group 11 preferably consists of three water pumps, including: The first water pump 111 has a flow rate that meets the flow requirements of both heat pumps when they start up; The second water pump 112 has a flow rate that meets the flow rate requirements of the three heat pumps when they are started. The third water pump 113 has a flow rate that meets the flow requirements of the five heat pumps when they start up. The second water pump group 21 preferably consists of two water pumps, including: The fourth water pump 211 has a flow rate that meets the flow requirements of the four heat pumps when they are started. The fifth water pump 212 has a flow rate that meets the start-up flow requirements of the five heat pumps.

[0028] Multiple sensors 5 are installed on both the main inlet pipe 3 and the main return pipe 4. The multiple sensors 5 include temperature sensors and differential pressure sensors.

[0029] Each heat pump in the first heat pump group 12 and the second heat pump group 22 is equipped with an inlet valve on its inlet pipe and an outlet valve on its outlet pipe.

[0030] The main water inlet pipe 3 is connected to a constant pressure water supply pipe 6.

[0031] This utility model also includes a control system 7, which is connected to the start / stop switches of all water pumps, the start / stop switches of all heat pumps, the inlet and outlet valves of all heat pumps, and all sensors 5. The control system 7 is also connected to some valves and meters, such as differential pressure bypass valves and heat meters in bypass pipelines.

[0032] All heat pumps in the first heat pump group 12 and the second heat pump group 22 are air source heat pumps.

[0033] Outdoor temperatures change constantly with the seasons and the alternation of day and night, and the indoor heating and cooling demands also change accordingly. The characteristics of these changes are analyzed below.

[0034] 1. Affected by changes in average outdoor temperature (humidity).

[0035] (1) The impact of changes in average outdoor temperature: The change in average outdoor temperature throughout the cooling / heating season is curved. During the cooling season, the higher the outdoor temperature, the more cooling is needed indoors, and the lower the outdoor temperature, the less cooling is needed indoors; during the heating season, the higher the outdoor temperature, the less heat is needed indoors, and the lower the outdoor temperature, the more heat is needed indoors.

[0036] (2) Affected by the temperature changes during the day and night: The temperature rises continuously in the morning, reaches the highest temperature of the day at 2 pm, and then gradually decreases. During the cooling season, the higher the outdoor temperature, the more cooling is needed indoors, and the lower the outdoor temperature, the less cooling is needed indoors. During the heating season, the higher the outdoor temperature, the less heat is needed indoors, and the lower the outdoor temperature, the more heat is needed indoors.

[0037] 2. Affected by user usage patterns.

[0038] Air conditioning usage rates vary in public buildings such as office buildings, schools, and hospitals at different times of day. The more fan coil units are activated at the terminal level, the greater the cooling / heating demand; conversely, the fewer fan coil units are activated, the smaller the cooling / heating demand. Characteristics of terminal cooling / heating demand variations: (1) During the cooling season, the higher the outdoor temperature, the more fan coil units are turned on; during the heating season, the lower the outdoor temperature, the more fan coil units are turned on; demand increases.

[0039] (2) During working hours, the number of fan coil units is high and the demand is large; after get off work, the number of fan coil units is low and the demand is reduced.

[0040] (3) Office buildings have fewer openings and lower demand on weekends and holidays; shopping malls are the opposite, with more openings and higher demand on weekends and holidays.

[0041] The multi-stage adjustment principle of this utility model will be analyzed below.

[0042] In response to the aforementioned temperature and cooling / heating changes, this invention designs two main systems: a first main system 1 and a second main system 2. In a preferred embodiment of this invention, the first main system 1 includes three water pumps and five air source heat pumps, and the second main system 2 includes two water pumps and five air source heat pumps. By regulating these two main systems, this invention can achieve nine levels of operational adjustment between 20% and 100%.

[0043] In this invention, the first water pump 111 can drive two heat pumps when started alone; the second water pump 112 can drive three heat pumps when started alone; the fourth water pump 211 can drive four heat pumps when started alone; the third water pump 113 or the fifth water pump 212 can drive five heat pumps when started alone; the first water pump 111 and the fourth water pump 211 can drive six heat pumps when started together; the second water pump 112 and the fourth water pump 211 can drive seven heat pumps when started together; the third water pump 113 and the fifth water pump 212 can drive eight heat pumps when started together; the third water pump 113 and the fourth water pump 211 can drive nine heat pumps when started together; and the third water pump 113 and the fifth water pump 212 can drive ten heat pumps when started together. This invention allows for nine energy-saving operating levels—20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, and 100%—based on the terminal's cooling / heating needs. The operating time and water supply temperature can be adjusted through a control system or manual control to regulate the energy-saving mode. The control system can be an intelligent centralized control system, offering faster response, better energy efficiency, and reduced labor costs. This intelligent centralized control system was designed by professionals in the field; with the hardware foundation of this invention, they can design suitable intelligent centralized control systems according to specific requirements.

[0044] In this invention, when the first host system 1 and the second host system 2 are running, only one water pump in each system can be started. When a water pump is started, the valves of the corresponding number of heat pump units are opened. The inlet and outlet valves of the heat pump units that are not in use are kept closed. In winter, the heat pump units that are not in use need to be drained to prevent freezing. In the first water pump group 11, the first water pump 111 and the second water pump 112 are backups for each other, and the first water pump 111 plus the second water pump 112 and the third water pump 113 are backups for each other. In the second water pump group 21, the fourth water pump 211 and the fifth water pump 212 are backups for each other.

[0045] This invention eliminates the need for frequent nine-level adjustments. On days with low peak cooling / heating demand, one water pump can be activated in each of the two main systems, such as the first water pump 111 and the fourth water pump 211. This is achieved by coordinating two heat pumps in the first heat pump group 12 and four heat pumps in the second heat pump group 22, allowing for three-level adjustments of 20%, 40%, and 60% based on daily demand.

[0046] Based on changes in outdoor temperature and operating data of the heat pump units, the water pumps and the corresponding number of heat pumps activated in each main unit system can be adjusted and switched. The adjustment cycle is generally around 10-30 days.

[0047] The following is an analysis of the effects of this utility model.

[0048] The relationship between air source heat pump units and annual comprehensive energy efficiency (APF) is as follows: Load factor: The ratio of actual output capacity to rated capacity; COP: Energy Efficiency; The relationship between load factor and coefficient of performance (COP) of air source heat pump units is nonlinear, and its pattern is influenced by the type of heat pump unit technology (fixed frequency / variable frequency), system design, and operating environment.

[0049] Typical relationship curves (general model) between load factor and COP for all-DC inverter air source heat pump units are shown below. Figure 3 .

[0050] Key interval characteristics: 1. Extremely low load range of <30%.

[0051] COP plummets: (1) Fixed frequency heat pump unit: Frequent start-up and shutdown cause additional energy loss, with start-up and shutdown losses reaching 15-30%, and one start-up and shutdown loss ≈ 3-5 minutes of full load energy consumption.

[0052] (2) Variable frequency heat pump units: The mechanical efficiency of the compressor decreases at low speeds, the refrigerant flow rate is insufficient, and the heat exchange deteriorates (the evaporator is prone to frosting, and the condensation superheat decreases). For example, at 20% load, the COP is only 50%-70% of the rated value. If the rated COP is 4.0, the actual COP is only 2.0-2.8.

[0053] 2. The high-efficiency load range of the variable frequency heat pump unit is 30%-70%, and the peak load range is 50%-70%.

[0054] The variable frequency compressor has a moderate speed, low mechanical loss, high efficiency, and small heat exchange temperature difference (evaporation temperature ↑, condensation temperature ↓).

[0055] The electronic expansion valve precisely controls superheat, reducing throttling losses.

[0056] Peak COP: Can reach 105-120% of the rated value. For example, the rated COP is 3.8, and the COP at 50% load is 4.2.

[0057] In this invention, the load rate of a single unit can be maintained within this range by starting and stopping some heat pump units. For example, when the total load is partially reached, starting one heat pump unit at 60% load is more efficient than starting three heat pump units at 20% load.

[0058] 3. High load range >80%.

[0059] COP slow descent: At high compressor speeds, frictional losses increase, and the heat exchange temperature difference increases (for every 1°C increase in condensing temperature, COP decreases by 2%-3%). Fixed-frequency generator units: When running at full load continuously, the COP is close to the rated value (without start-stop losses). Variable frequency units: COP is 5-10% lower than the peak value, but still higher than that of fixed frequency units.

[0060] The air source heat pump in this invention can be a fixed-frequency unit. Through multi-stage adjustment of the unit's operation, the heat pump can operate without being affected by changes in ambient temperature or indoor heating and cooling demand, and always maintain 100% load rate operation. This ensures that the system's operating energy efficiency reaches the unit's rated energy efficiency, avoiding the problem of existing technologies where 70% of the operating time deviates from the rated energy efficiency range of the main unit. Compared with this, energy saving is no less than 25%.

[0061] The air source heat pump in this invention can be a variable frequency unit. Through multi-stage adjustment of the unit's operation, the heat pump can operate without being affected by changes in ambient temperature or indoor heating and cooling demand. It always operates in the high-efficiency load range of 30%-70% load rate and operates in the peak load range of 50%-70% load rate for most of the time, further improving energy efficiency to 105-120% of the rated value, resulting in energy savings of no less than 15%.

[0062] This invention demonstrates superior energy efficiency in water pumps: Existing water pumps operate at full load throughout their entire lifespan, resulting in 30%-70% of wasted power output for over 80% of the operating cycle. This invention, however, can flexibly utilize different single or dual pumps based on changes in ambient temperature and indoor heating / cooling demands, adjusting the circulating water volume to deliver only the required amount to the terminal. This results in energy savings of at least 60%. While the increased number of pumps raises costs, the reduced pump power and energy consumption ultimately lead to lower overall costs over the year. Furthermore, the longer the pumps are used, the more the cost is amortized, highlighting the significant advantages.

[0063] Overall, the energy consumption of fixed-frequency units is reduced by more than 35%, while that of variable-frequency units is reduced by more than 25%.

[0064] The proper operation of this utility model requires meticulous management and control. The number and power of the heat pump units should be determined based on temperature changes and cooling / heating needs in different regions. Then, a suitable water pump should be selected. During use, multi-level control of the water pump and heat pump units is required based on changes in cooling / heating needs. This model is suitable for specialized organizations to manage the air conditioning system.

[0065] The above description is merely a preferred embodiment of this utility model, but the protection scope of this utility model is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this utility model should be included within the protection scope of this utility model. Therefore, the protection scope of this utility model should be determined by the scope of the claims.

Claims

1. An air source heat pump system with host multi-stage regulation and circulating water variable flow, characterized in that: It includes a first host system (1) and a second host system (2). The first host system (1) includes a first water pump group (11) and a first heat pump group (12). The second host system (2) includes a second water pump group (21) and a second heat pump group (22). Multiple water pumps in the first water pump group (11) and the second water pump group (21) are connected in parallel. Multiple heat pumps in the first heat pump group (12) and the second heat pump group (22) are connected in parallel. The first water pump group (11) and the first heat pump group (12) are connected through pipelines. The second water pump group (21) and the second heat pump group (22) are connected through pipelines. The first host system (1) and the second host system (2) are connected in parallel. The water inlet pipes of the first host system (1) and the second host system (2) are both connected to the main water inlet pipe (3). The water outlet pipes of the first host system (1) and the second host system (2) are both connected to the main return water pipe (4). The pumps in the first pump group (11) have the same head but different flow rates. The pump with the smallest flow rate is the one that can meet the flow rate requirement when starting up at least one heat pump in the first heat pump group (12), and the pump with the largest flow rate is the one that can meet the flow rate requirement when starting up all heat pumps in the first heat pump group (12). In the second water pump group (21), the multiple water pumps have the same head but different flow rates. The pump with the smallest flow rate is the one that can meet the flow rate requirement when starting up at least one heat pump in the second heat pump group (22), and the pump with the largest flow rate is the one that can meet the flow rate requirement when starting up all heat pumps in the second heat pump group (22).

2. The air source heat pump system of claim 1, wherein: The first heat pump group (12) and the second heat pump group (22) each have five heat pumps; The first water pump set (11) includes: The first water pump (111) has a flow rate that meets the flow rate requirements of the two heat pumps when they are started. The second water pump (112) has a flow rate that meets the flow rate requirements of the three heat pumps when they are started. The third water pump (113) has a flow rate that meets the flow rate requirements of the five heat pumps when they start up. The second water pump set (21) includes: The fourth water pump (211) has a flow rate that meets the flow rate requirements of the four heat pumps when they are started. The fifth water pump (212) has a flow rate that meets the flow requirements of the five heat pumps when they start up.

3. The air source heat pump system of claim 1 or 2, wherein: Multiple sensors (5) are installed on both the main water inlet pipe (3) and the main water return pipe (4), including a temperature sensor and a differential pressure sensor.

4. The air source heat pump system of claim 3, wherein: Each heat pump in the first heat pump group (12) and the second heat pump group (22) is equipped with an inlet valve on its inlet pipe and an outlet valve on its outlet pipe.

5. The air source heat pump system of claim 1 or 2, wherein: The main water inlet pipe (3) is connected to a constant pressure water supply pipe (6).

6. The air source heat pump system with multi-stage main unit regulation and variable flow rate of circulating water according to claim 4, characterized in that: It also includes a control system (7), which is connected to the start / stop switches of all water pumps, the start / stop switches of all heat pumps, the inlet and outlet valves of all heat pumps, and all sensors (5).

7. An air source heat pump system with multi-stage main unit regulation and variable flow rate of circulating water according to claim 1 or 2, characterized in that: All heat pumps in the first heat pump group (12) and the second heat pump group (22) are air source heat pumps.

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