Heat exchange energy-saving pipe-in-pipe circulation system

Abstract

The invention belongs to the technical field of residential heating systems, and particularly relates to a heat exchange energy-saving pipe-in-pipe circulation system. Comprising a main pipeline unit and at least one home-entry unit. The main pipeline unit comprises a water heater, at least one main liquid inlet pipe, at least one main return pipe and at least one main circulating pump; the home-entry unit comprises a pipe-in-pipe pipeline, a home-entry liquid inlet pipe, a home-entry pump, a home-entry return pipe and a heat exchanger; the main pipeline unit is used for supplying hot water in a centralized mode, the home-entry unit is used for daily hot water use of each household, in the home-entry unit, the home-entry pump, the first channel, the second channel, the home-entry backflow pipe and the heating channel form the circulating preheating loop, and when the home-entry pump is started, a medium in the circulating preheating loop flows, so that the heat exchange efficiency is improved. And heat conduction is carried out through the heat exchanger, so that the medium is preheated. When the water consumption point is opened, hot water can be instantly discharged from each water consumption point of the pipe-in-pipe pipeline.

Description

Technical Field

[0001] The present invention belongs to the technical field of residential heating systems, and particularly refers to a heat exchange energy-saving pipe-in-pipe circulation system. Background Art

[0002] A hot water circulation system is a system used to provide instant hot water. The cold water in the hot water pipe is sent back to the water heater for reheating through a circulation pump to ensure that hot water can be obtained immediately when the user turns on the faucet.

[0003] Patent No. CN109611944B discloses a pipe-in-pipe hot water circulation system, which includes a water heater, a circulation pump, a check-type starting valve, a hot water pipeline composed of hot water pipes and pipe joints, and a tail valve connected to an external device in sequence. The liquid inlet end of the circulation pump is connected to the output end of the water heater, and its output end is connected to the check-type starting valve; a hot water flow channel communicating with the liquid inlet cavity of the starting valve and a return water flow channel communicating with the return cavity of the starting valve are arranged in the hot water pipe, and the hot water pipes are connected to each other through pipe joints; a tail valve is arranged at the liquid outlet end of the hot water pipe, and the tail valve includes a tail valve body. A tail valve liquid inlet cavity communicating with the hot water flow channel and a tail valve return cavity communicating with the return water flow channel are arranged in the tail valve body, and the tail valve liquid inlet cavity and the tail valve return cavity can communicate with an external device. This pipe-in-pipe hot water circulation system has the characteristics of energy conservation and environmental protection, convenient pipeline layout, and rapid water outlet.

[0004] The above-mentioned pipe-in-pipe hot water circulation system is mainly applicable to single-family residences or hotels. When applied to multi-family residences with centralized hot water supply, the following problems will occur:

[0005] 1. Each household has an independent water meter. When the hot water pipe of each household only circulates internally and does not use hot water, the hot water will generate a reading and be charged when passing through the water meter, but in fact, no hot water is used, resulting in incorrect water meter readings.

[0006] 2. For pipelines with low hot water usage frequency, heat waste will occur during hot water circulation, increasing the usage cost. Summary of the Invention

[0007] The purpose of the present invention is to provide a heat exchange energy-saving pipe-in-pipe circulation system with a simple structure, accurate billing, and instant hot water supply.

[0008] The purpose of the present invention is achieved as follows:

[0009] A heat exchange energy-saving pipe-in-pipe circulation system includes a main pipeline unit and at least one household unit connected to the main pipeline unit;

[0010] The main pipeline unit includes a water heater, at least one main liquid inlet pipe communicating with the liquid outlet end of the water heater, at least one main return pipe communicating with the return end of the water heater, and at least one main circulation pump;

[0011] The household unit includes:

[0012] A pipe-in-pipe pipeline, having a first channel and a second channel;

[0013] A household inlet liquid pipe, connecting the main inlet liquid pipe and the first channel;

[0014] A household pump, installed between the household inlet liquid pipe and the pipe-in-pipe pipeline;

[0015] A household return pipe, connecting the second channel and the inlet end of the household pump, and a water meter is installed; and

[0016] A heat exchanger, having a heat medium channel connecting the main inlet liquid pipe and a heating channel connected in series on the household return pipe;

[0017] A circulating preheating loop is formed among the household pump, the first channel, the second channel, the household return pipe and the heating channel,

[0018] The medium in the circulating preheating loop can conduct heat through the heat exchanger.

[0019] The present invention is further provided with a heat medium inlet end and a heat medium outlet end which are connected to the heat medium channel and are arranged on the heat exchanger,

[0020] The heat medium inlet end is connected to the main inlet liquid pipe or the household inlet liquid pipe through a heat medium inlet pipe, and the heat medium outlet end is connected to the main return pipe through a heat medium outlet pipe.

[0021] The present invention is further provided with that the main pipeline unit includes a plurality of main inlet liquid pipes and main return pipes with the same number,

[0022] All the main inlet liquid pipes are connected to the outlet end of the water heater through a total inlet liquid pipe,

[0023] All the main return pipes are connected to the return end of the water heater through a total return pipe,

[0024] A plurality of household units are respectively installed between the corresponding main inlet liquid pipe and the main return pipe.

[0025] The present invention is further provided with that the heat medium channel of the heat exchanger is connected in series on the main inlet liquid pipe, and the main inlet liquid pipe is connected to the main return pipe.

[0026] The present invention is further provided with that the main pipeline unit includes a plurality of main inlet liquid pipes and one main return pipe, and all the main inlet liquid pipes are connected to the outlet end of the water heater through a total inlet liquid pipe;

[0027] A plurality of household units are respectively installed on the corresponding main inlet liquid pipes.

[0028] The present invention is further provided with a household valve arranged on the household inlet liquid pipe.

[0029] The present invention is further provided with a plurality of main circulation pumps connected in parallel at the liquid outlet end or the reflux end of the water heater, and a main inlet check valve is connected in series at the liquid outlet end of each main circulation pump.

[0030] The present invention is further provided with that the household unit further includes a pipe-in-pipe inlet valve, which has a pipe-in-pipe installation end connecting the pipe-in-pipe pipeline, a first inlet installation end for communicating with the first channel, and a reflux installation end for communicating with the second channel.

[0031] The household inlet pipe is connected to the first inlet installation end through a household pump.

[0032] A liquid outlet check valve for discharging liquid is arranged at the reflux installation end and is connected to the household reflux pipe.

[0033] The present invention is further provided with that the pipe-in-pipe inlet valve is further provided with a second inlet installation end for communicating with the second channel, and a liquid inlet check valve for inletting liquid is arranged at the second inlet installation end and is connected to the household inlet pipe.

[0034] The present invention is further provided with that the pipe-in-pipe pipeline includes a pipe-in-pipe main path and at least one pipe-in-pipe branch path. At least one pipe-in-pipe circulation end or / and at least one pipe-in-pipe liquid outlet end is arranged on the pipe-in-pipe branch path. An electric actuator for controlling the on-off of the first channel and the second channel is arranged on the pipe-in-pipe circulation end.

[0035] The household unit further includes a control module for controlling the operation of the household pump and the electric actuator.

[0036] The prominent and beneficial technical effects of the present invention compared with the prior art are as follows:

[0037] 1. The main pipeline unit of the present invention is used for centralized hot water supply, and the household unit is used for daily hot water use of each household. In the household unit, a circulating preheating loop is formed among the household pump, the first channel, the second channel, the household reflux pipe and the heating channel. When the household pump is started, the medium (water) in the circulating preheating loop flows and heat conduction is carried out through the heat exchanger, so as to realize the preheating of water. When the water use point is opened, hot water can be instantaneously discharged at each water use point of the pipe-in-pipe pipeline. In addition, when the water use point is closed, the circulation of the circulating preheating loop will not increase the water meter reading, protecting the rights and interests of users.

[0038] 2. The household unit of the present invention further includes a control module for controlling the operation of the household pump and the corresponding electric actuator. The control module is preferably an induction switch, which is generally arranged on the necessary path of the water use point, such as at the door or on the wall near the water use point. Cold water is stored in the pipelines that are not used for a long time. When the induction switch senses a user, it controls the household pump and the corresponding electric actuator to work, realizing the circulation of the in-pipe branch. Then, preheating is carried out through the heat exchanger, so that before the user uses the water, the pipeline where the water use point is located becomes hot water through circulation, ensuring that hot water can be instantaneously discharged as soon as the user opens the water use point. At the same time, the in-pipe branches where no user is detected do not circulate, which is beneficial to reducing the loss of hot water in other pipelines. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 is a schematic structural diagram of the first heat exchange energy-saving in-pipe circulation system of the present invention.

[0040] Figure 2 is a schematic structural diagram of the first household unit of the present invention.

[0041] Figure 3 is a schematic structural diagram of the water use point of the in-pipe pipeline of the present invention.

[0042] Figure 4 is a schematic structural diagram of the second heat exchange energy-saving in-pipe circulation system of the present invention.

[0043] Figure 5 is a schematic structural diagram of the third heat exchange energy-saving in-pipe circulation system of the present invention.

[0044] Figure 6 is a schematic structural diagram of the fourth heat exchange energy-saving in-pipe circulation system of the present invention.

[0045] Figure 7 is a schematic structural diagram of the second household unit of the present invention.

[0046] The meanings represented by the reference numerals in the drawings:

[0047] Main pipeline unit 1; Household unit 2; Cold water inlet pipe 3;

[0048] Water heater 11; Main liquid inlet pipe 12; Main liquid inlet control valve 121; Main return pipe 13; Main return control valve 131; Main return check valve 132; Main circulation pump 14; Main liquid inlet check valve 141; Total liquid inlet pipe 15; Total return pipe 16;

[0049] In-pipe pipeline 21; In-pipe circulation end 211; In-pipe liquid outlet end 212; Electric actuator 213; Inductive control module 214; Liquid outlet valve 215; Liquid outlet valve core 216; Three-way tail valve 217;

[0050] Inlet liquid pipe 22; Inlet pump 23; Inlet return pipe 24;

[0051] Heat exchanger 25; Heat medium inlet end 251; Heat medium outlet end 252; Heat medium inlet pipe 253; Heat medium outlet pipe 254; Heat medium check valve 255; Heat medium control valve 256; Heating inlet end 257; Heating outlet end 258;

[0052] Inlet valve 26; Water meter 27;

[0053] Inlet valve for pipe-in-pipe 28; Pipe-in-pipe installation end 281; First inlet installation end 282; Return installation end 283; Outlet check valve 284; Second inlet installation end 285; Inlet check valve 286. Detailed implementation mode

[0054] The present invention will be further described below in conjunction with specific embodiments:

[0055] Embodiment 1:

[0056] As Figure 1 shown, a heat exchange energy-saving pipe-in-pipe circulation system is used in multi-family residences and includes a main pipeline unit 1 and at least one inlet unit 2 connected to the main pipeline unit 1. The main pipeline unit 1 is used for centralized supply of hot water, and the inlet unit 2 is used for daily hot water use of each household.

[0057] The main pipeline unit 1 mainly includes a water heater 11, at least one main inlet pipe 12, at least one main return pipe 13, and at least one main circulation pump 14.

[0058] The water heater can be an electric water heater, a gas water heater, a solar water heater, a heat pump water heater, a boiler system, an instant water heater, a storage water heater, etc. The water heater in this embodiment has a hot water outlet, a hot water return port, and a cold water inlet. The main inlet pipe 12 is connected to the hot water outlet (i.e., the liquid outlet end of the water heater 11), the main return pipe 13 is connected to the hot water return port (i.e., the return end of the water heater 11), and a cold water inlet pipe 3 is connected to the cold water inlet. The cold water inlet pipe 3 is generally a tap water pipe for replenishing cold water. In another embodiment, the hot water return port and the cold water inlet can also be combined into one interface for use.

[0059] The main circulation pump 14 can be arranged at the liquid outlet end of the water heater 11 or the return end of the water heater 11 for hot water pressurization, and its quantity depends on the demand of the system. When the demand is relatively small, the system is generally equipped with one main circulation pump 14, and a main inlet check valve 141 is arranged at the liquid outlet end of the main circulation pump 14 to prevent the hot water inside the main inlet pipe 12 from flowing back; when the system demand is relatively large, generally two or more main circulation pumps 14 are configured. As Figure 1As shown in the figure, a main inlet control valve 121 is provided at the liquid outlet end of the water heater 11. The main inlet control valve 121 is preferably a manual control valve. Two main circulation pumps 14 are connected in parallel on the main inlet pipe 12 connecting the main inlet control valve 121. A main inlet check valve 141 is connected in series at the liquid outlet end of each main circulation pump 14. During peak water usage, the two main circulation pumps 14 work simultaneously; during low peak water usage, one of the main circulation pumps 14 works, so as to reduce the operating cost on the premise of meeting the user's needs. In addition, when one of the main circulation pumps 14 fails, the other main circulation pump 14 can replace it to work, ensuring that the system works without stopping for 24 hours, thereby reducing the user's losses.

[0060] On the main return pipe 13 close to the water heater 11, a main return control valve 131 and a main return check valve 132 are arranged in sequence, as Figure 1 shown. In this embodiment, there are two main return control valves 131, one is an electric control valve and the other is a manual control valve. The two are respectively installed at both ends of the main return check valve 132. The main return check valve 132 is used to prevent the main return pipe 13 from flowing back.

[0061] As Figure 2 shown, the household unit 2 includes a pipe-in-pipe pipeline 21, a household inlet pipe 22, a household pump 23, a household return pipe 24, a pipe-in-pipe inlet valve 28, and a heat exchanger 25.

[0062] The pipe-in-pipe pipeline 21 has a first channel and a second channel. Specifically, the pipe-in-pipe pipeline 21 includes a pipe-in-pipe main path and at least one pipe-in-pipe branch path. Both are spliced by corresponding pipe-in-pipes and pipe-in-pipe joints. Each pipe-in-pipe includes an inner pipe and an outer pipe arranged coaxially. An inner flow path is formed inside the inner pipe, and an outer flow path is formed between the inner pipe and the outer pipe. The inner flow path and the outer flow path correspond to the first channel and the second channel respectively. On the pipe-in-pipe main path or the pipe-in-pipe branch path, corresponding water outlet devices such as faucets and shower heads are arranged according to the position of each hot water usage point.

[0063] For example: for a household, generally, the pipe-in-pipe main path can be understood as the pipeline arranged between each room, and the pipe-in-pipe branch path can be understood as the pipeline arranged in a single room. The corresponding pipe-in-pipe branch paths are set according to the number of rooms. The number of water usage points on the pipe-in-pipe branch path can be set according to the water usage points required in each room. For example: generally, one hot water usage point is set in the kitchen, two hot water usage points (corresponding to the washbasin and the shower head) are set in the bathroom, and one hot water usage point is set in the balcony room, etc.

[0064] The in-pipe-in-pipe liquid inlet valve 28 is used to connect the in-pipe-in-pipe pipeline 21, the household liquid inlet pipe 22 and the household return pipe 24. It has an in-pipe-in-pipe installation end 281 for connecting the in-pipe-in-pipe pipeline 21, a first liquid inlet installation end 282 for communicating with the first channel, and a return installation end 283 for communicating with the second channel. A liquid outlet check valve 284 for liquid outlet is provided at the return installation end 283 and is connected to the household return pipe 24.

[0065] As Figure 2 shown, in this embodiment, the first channel is the inner flow channel and the second channel is the outer flow channel.

[0066] The household liquid inlet pipe 22 is an ordinary pipe, one end is connected to the main liquid inlet pipe 12, and the other end is connected to the first liquid inlet installation end 282 through the household pump 23, that is, the household pump 23 is installed between the household liquid inlet pipe 22 and the first channel of the in-pipe-in-pipe pipeline 21. And a household valve 26 and a water meter 27 are provided on the household liquid inlet pipe 22. The household valve 26 is preferably a manual control valve for controlling the entry of hot water; the water meter 27 is used to calculate the hot water consumption, which is convenient for the hot water operator to charge.

[0067] The heat exchanger 25 has a heat medium channel communicating with the main liquid inlet pipe 12 and a heating channel connected in series on the household return pipe 24. Specifically, a heat medium inlet end 251 and a heat medium outlet end 252 communicating with the heat medium channel are provided on the heat exchanger 25. The heat medium inlet end 251 is communicated with the main liquid inlet pipe 12 or the household liquid inlet pipe 22 through the heat medium inlet pipe 253, and the heat medium outlet end 252 is communicated with the main return pipe 13 through the heat medium outlet pipe 254. A heat medium check valve 255 for preventing backflow and / or a heat medium control valve 256 for controlling the operation of the heat medium channel are provided on the heat medium outlet pipe 254.

[0068] In this embodiment, the inlet end of the heat medium inlet pipe 253 is arranged on the household liquid inlet pipe 22 between the household valve 26 and the water meter 27. In this way, when not living for a long time, the household valve 26 is manually closed, and the hot water in the main liquid inlet pipe 12 will not enter the in-pipe-in-pipe pipeline 21 and the heat exchanger 25, preventing the heat exchanger 25 from generating additional energy loss; at the same time, during normal use, the amount of hot water in the heat medium channel of the heat exchanger 25 is not consumed, only a part of the heat is consumed, and the hot water in the heat medium inlet pipe 253 does not pass through the water meter 27, which will not affect the reading of the water meter 27. In addition, a heat medium control valve 256 is provided on the heat medium outlet pipe 254. The heat medium control valve 256 is preferably a manual control valve to control the flow rate of the heat medium channel.

[0069] The heat exchanger 25 is also provided with a heating liquid inlet end 257 and a heating liquid outlet end 258 communicating with the heating channel. The household return pipe 24 includes a first household return pipe and a second household return pipe. The first household return pipe is installed between the return installation end 283 and the heating liquid inlet end 257, and the second household return pipe is installed between the heating liquid outlet end 258 and the liquid inlet end of the household valve 26. That is, the second household return pipe is connected to the household liquid inlet pipe 22 behind the water meter 27, so that a circulating preheating loop is formed among the household pump 23, the first channel and the second channel of the pipe-in-pipe pipeline 21, the first household return pipe, the heating channel and the second household return pipe. When the household pump 23 is started, the medium (water) in the circulating preheating loop flows and conducts heat through the heat exchanger 25, thereby realizing the preheating of water. When the water usage point is opened (the user uses the water outlet device), hot water can be instantaneously supplied at each water usage point of the pipe-in-pipe pipeline 21. At the same time, when the water usage point is closed, the circulation of the circulating preheating loop will not increase the reading of the water meter 27, protecting the rights and interests of users.

[0070] Generally, the hot water in the main pipeline unit 1 is continuously circulated and heated, and there is always hot water in the heat medium channel of the heat exchanger 25. For users, as long as the household pump 23 starts to work, the heat exchanger 25 can transfer heat to the circulating preheating loop to meet the needs of users. However, the operation of the heat exchanger 25 will cause heat loss in the main liquid inlet pipe 12, which is disadvantageous for the hot water operator. To solve this problem, the hot water operator can make up for it in the form of policy subsidies, including the loss in the hot water cost, or installing a hot water meter on the heat medium liquid inlet pipe 253 or the heat medium liquid outlet pipe 254 for separate billing.

[0071] In addition, the hot water operator can control the return flow of the main return pipe 13 by adjusting the main return control valve 131. Generally, during low water demand periods (such as late at night), the main return control valve 131 needs to be closed slightly to prevent excessive hot water circulation in the pipeline and resulting in excessive losses; during normal water demand periods (such as during the day), the main return control valve 131 needs to be opened wide to ensure that the household unit 2 can normally use the heat exchanger 25; during peak water demand periods (such as in the morning or evening), the main return control valve 131 needs to be closed slightly or closed to give priority to ensuring the hot water supply at the water usage points. In this embodiment, the purpose of designing the electric control valve is to achieve precise control and intelligent control.

[0072] Among them, in order to increase the water consumption of users at the water-using point, the in-pipe-in-pipe liquid inlet valve 28 is preferably further provided with a second liquid inlet installation end 285 for connecting the second channel. The second liquid inlet installation end 285 is provided with a liquid inlet check valve 286 for liquid inlet and is connected to the household liquid inlet pipe 22. That is, the household liquid inlet pipe 22 is provided with a first liquid inlet branch pipe connecting the liquid inlet end of the household pump 23 and a second liquid inlet branch pipe connecting the second liquid inlet installation end 285. When the main circulation pump 14 is in working state, the water inlet pressure of the main liquid inlet pipe 12 is sufficient to open the liquid inlet check valve 286. At this time, when the water-using point of the in-pipe-in-pipe pipeline 21 is opened, the main liquid inlet pipe 12 can output hot water through the first channel and the second channel simultaneously to ensure the water volume at the water-using point.

[0073] As Figure 2 and 3 shown, at least one in-pipe-in-pipe loop end 211 or / and at least one in-pipe-in-pipe liquid outlet end 212 are provided on at least one in-pipe-in-pipe branch. An electric actuator 213 for controlling the on-off of the first channel and the second channel is provided on the in-pipe-in-pipe loop end 211.

[0074] Specifically, a three-way tail valve 217 is provided at the water-using point of the in-pipe-in-pipe branch. The three-way tail valve 217 includes an in-pipe-in-pipe connection end connecting the in-pipe-in-pipe, an in-pipe-in-pipe liquid outlet end 212 for installing a water outlet device, and an in-pipe-in-pipe loop end 211 for installing the electric actuator 213. Channels connecting the inner flow path and the outer flow path are respectively provided between the in-pipe-in-pipe connection end, the in-pipe-in-pipe liquid outlet end 212, and the in-pipe-in-pipe loop end 211. The electric actuator 213 realizes the opening and closing of the two by sealing the inner flow path or the outer flow path. Normally, the electric actuator 213 is in a closed state. When internal circulation preheating is required, the inner flow path or the outer flow path is opened to realize the conduction of the two.

[0075] A liquid outlet valve core 216 and a liquid outlet valve 215 are provided on the in-pipe-in-pipe liquid outlet end 212. The liquid outlet valve 215 is preferably an angle valve, and the liquid outlet valve core 216 is preferably a delayed temperature control valve core. When it does not sense hot water, it will block one of the flow paths (block the inner flow path or the outer flow path), and the other flow path always remains unblocked. After the liquid outlet valve 215 is opened, the unblocked flow path gives priority to discharging liquid. When the delayed temperature control valve core senses hot water, the other flow path is opened, and liquid is discharged simultaneously through the inner and outer flow paths. For the specific structure of the delayed temperature control valve core, please refer to patent documents such as patent CN 213271075U and CN 214367847U.

[0076] Among them, the household unit 2 further includes a control module for controlling the operation of the household pump 23 and the corresponding electric actuator 213. The control module includes an induction control module 214, a mechanical control module, or a remote control module. In this embodiment, the induction control module 214 is preferably selected. The induction control module 214 is an induction switch, and the number of induction switches corresponds to that of the electric actuators 213, which can be one-to-one or one induction switch corresponding to multiple electric actuators 213, mainly used to control the operation of the household pump 23 and the corresponding electric actuators 213. The induction control module 214 is generally arranged on the only way to the water use point, such as at the door or on the wall near the water use point. The pipelines that are not used for a long time all store cold water. When the induction switch senses a user, it controls the household pump 23 and the corresponding electric actuator 213 to work, realizing the circulation of the in-pipe branch, and then preheating through the heat exchanger 25, so that before the user uses it, the pipeline where the water use point is located becomes hot water through circulation, ensuring that the user can get hot water immediately when opening the water use point. At the same time, the other in-pipe branches that do not detect users do not participate in the circulation, which is beneficial to reducing the loss of hot water in other pipelines.

[0077] The preheating time of the circulation preheating loop is determined by the working time of the household pump 23. This working time can be set through the program of the control module or feedback-controlled by a temperature sensor. For example, a temperature sensor is arranged near the water use point or on the household return pipe 24. When the water temperature detected by the temperature sensor reaches the preset temperature, the household pump 23 can be controlled to turn off.

[0078] In this embodiment, as Figure 1 shown, assume there are five water use points, namely the 1st water use point, the 2nd water use point, the 3rd water use point, the 4th water use point, and the 5th water use point. Among them, a liquid outlet valve core 216, a liquid outlet valve 215, and an electric actuator 213 are arranged on the 1st water use point, the 2nd water use point, the 3rd water use point, and the 4th water use point. Corresponding 1st induction switch, 2nd induction switch, 3rd induction switch, and 4th induction switch are arranged near different water use points. Assume that when a user passes by the 1st induction switch, it will control the household pump 23 and the 1st electric actuator of the 1st water use point to open. At this time, the inlet chamber of the household pump 23, the in-pipe branch, the inner and outer flow channels of the part of the in-pipe main road connecting the in-pipe branch, and the household return pipe 24 form the current circulation preheating loop, and the cold water in the pipeline is preheated through the heat exchanger 25. When the 1st water use point is opened, hot water can be enjoyed immediately, avoiding long-term waiting for hot water and saving the initial cold water discharge volume, thus improving the quality of life.

[0079] In addition, only a liquid outlet valve core 216 and a liquid outlet valve 215 are provided on the pipe-in-pipe branch of the 5th water usage point. It is located near the 2nd water usage point with a relatively high usage frequency. By using or preheating the hot water at the 2nd water usage point, it can ensure that a certain amount of hot water is stored in the pipeline adjacent to the 5th water usage point, enabling the 5th water usage point to achieve hot water supply relatively quickly.

[0080] Embodiment 2:

[0081] This embodiment is basically the same as Embodiment 1, and the differences are as follows:

[0082] This embodiment is applicable to multi-family residential buildings and villa groups with relatively small hot water demand.

[0083] As Figure 4 shown, the main pipeline unit 1 mainly includes a water heater 11, a main liquid inlet pipe 12, a main return pipe 13, and a main circulation pump 14. The main circulation pump 14 is installed at the return end of the water heater 11, that is, on the main return pipe 13.

[0084] A plurality of household units 2 are provided on the main pipeline unit 1. Among them, four household units 2 are shown in this embodiment. The household unit 2 includes a pipe-in-pipe pipeline 21, a household liquid inlet pipe 22, a household pump 23, a household return pipe 24, a pipe-in-pipe liquid inlet valve 28, and a heat exchanger 25.

[0085] The heat exchanger 25 is provided with a heat medium inlet end 251 and a heat medium outlet end 252 communicating with the heat medium channel. The heat medium inlet end 251 communicates with the main liquid inlet pipe 12 through a heat medium inlet pipe 253, and the heat medium outlet end 252 communicates with the main return pipe 13 through a heat medium outlet pipe 254. A heat medium check valve 255 for preventing backflow is provided on the heat medium outlet pipe 254.

[0086] In another installation method, the heat medium inlet pipe 253 of the heat exchanger 25 of the first household communicates with the main liquid inlet pipe 12. The heat medium outlet pipe 254 of the first household is directly connected to the heat medium inlet pipe 253 of the heat exchanger 25 of the second household. Then, the heat medium outlet pipe 254 of the second household can be directly connected to the heat medium inlet pipe 253 of the heat exchanger 25 of the third household or directly connected back to the main return pipe 13 through the heat medium check valve 255. At this time, the household liquid inlet pipe 22 of the second household can also be directly installed on the heat medium outlet pipe 254 (equivalent to the heat medium inlet pipe 253 of the second household) of the first household.

[0087] The household inlet liquid pipe 22 is an ordinary pipe. Its front end is connected to the main inlet liquid pipe 12 and is provided with a household inlet valve 26 and a water meter 27. Its rear end contains a first inlet liquid branch pipe connected to the inlet liquid end of the household inlet pump 23 and a second inlet liquid branch pipe connected to the second inlet liquid installation end 285. The first inlet liquid branch pipe is connected to the first inlet liquid installation end 282 of the in-pipe inlet valve 28 through the household inlet pump 23 connecting pipe. The second inlet liquid branch pipe is connected to the second inlet liquid installation end 285 of the in-pipe inlet valve 28 through the inlet liquid check valve 286. The return installation end 283 of the in-pipe inlet valve 28 is connected to the household return pipe 24 through the outlet liquid check valve 284.

[0088] The heat exchanger 25 is also provided with a heating inlet liquid end 257 and a heating outlet liquid end 258 that communicate with the heating channel. The household return pipe 24 includes a first household return pipe and a second household return pipe. The first household return pipe is installed between the return installation end 283 and the heating inlet liquid end 257. The second household return pipe is installed between the heating outlet liquid end 258 and the inlet liquid end of the household inlet valve 26. It is equivalent to the second household return pipe being connected to the household inlet liquid pipe 22 behind the water meter 27, so that a circulating preheating loop is formed among the household inlet pump 23, the first channel, the second channel, the first household return pipe, the heating channel, and the second household return pipe.

[0089] Embodiment Three:

[0090] This embodiment is basically the same as Embodiment One, and the differences are as follows:

[0091] This embodiment is applicable to multi-family residential buildings with a large demand for hot water, especially in unit buildings.

[0092] As Figure 5 shown, the main pipeline unit 1 includes multiple main inlet liquid pipes 12 and main return pipes 13 with the same quantity. All the main inlet liquid pipes 12 are connected to the outlet liquid end of the water heater 11 through the total inlet liquid pipe 15. All the main return pipes 13 are connected to the return end of the water heater 11 through the total return pipe 16. For example, in a unit building, a total inlet liquid pipe 15 and a total return pipe 16 are vertically arranged. In each floor, there is a corresponding main inlet liquid pipe 12 connected to the total inlet liquid pipe 15 and a main return pipe 13 connected to the total return pipe 16.

[0093] In this embodiment, a main inlet liquid control valve 121 is provided at the outlet liquid end of the water heater 11. The main inlet liquid control valve 121 is preferably a manual control valve. Two main circulation pumps 14 are connected in parallel on the total inlet liquid pipe 15 connected to the main inlet liquid control valve 121. The outlet liquid end of each main circulation pump 14 is connected in series with a main inlet liquid check valve 141. A main return control valve 131 and a main return check valve 132 are sequentially arranged on the total return pipe 16 near the water heater 11. Specifically, an electric control valve, a main return check valve 132, and a manual control valve are provided.

[0094] The household unit 2 of this embodiment is basically the same as that of the first embodiment. Each user on each floor can connect the household inlet liquid pipe 22 of the household unit 2 to the main inlet liquid pipe 12 of the corresponding floor and connect the heat medium outlet pipe 254 of the heat exchanger 25 to the main return pipe 13 of the corresponding floor, so as to achieve parallel pipe layout.

[0095] Embodiment Four:

[0096] This embodiment is basically the same as the first embodiment, and the difference lies in:

[0097] This embodiment is applicable to multi-family residential buildings with large hot water demand, especially unit buildings.

[0098] As Figure 6 shown, the main pipeline unit 1 includes multiple main inlet liquid pipes 12 and one main return pipe 13. All the main inlet liquid pipes 12 are connected to the outlet end of the water heater 11 through the total inlet liquid pipe 15. For example, in a unit building, a total inlet liquid pipe 15 and a main return pipe 13 are vertically arranged, and one main inlet liquid pipe 12 is arranged between the total inlet liquid pipe 15 and the main return pipe 13 on each floor.

[0099] In this embodiment, a main inlet liquid control valve 121 is arranged at the outlet end of the water heater 11. The main inlet liquid control valve 121 is preferably a manual control valve. Two main circulation pumps 14 are connected in parallel on the total inlet liquid pipe 15 connected to the main inlet liquid control valve 121. The outlet end of each main circulation pump 14 is connected in series with a main inlet liquid check valve 141. A main return control valve 131 and a main return check valve 132 are sequentially arranged on the total return pipe 16 close to the water heater 11, specifically including an electric control valve, a main return check valve 132 and a manual control valve.

[0100] As Figure 7 shown, each user on each floor connects the household inlet liquid pipe 22 of the household unit 2 to the main inlet liquid pipe 12 of the corresponding floor, and directly connects the heat medium channel of the heat exchanger 25 in series on the main inlet liquid pipe 12, so as to achieve series-parallel hydraulic balance pipe layout.

[0101] Embodiment Five:

[0102] This embodiment is basically the same as the first embodiment, and the difference lies in:

[0103] A liquid outlet valve 215 is directly arranged at the water-using point of the pipe-in-pipe branch, so that the inner flow channel and the outer flow channel can be connected at the pipe-in-pipe outlet end 212 of the pipe-in-pipe branch. In this way, without the need for an electric actuator 213, when the household pump 23 is started, the pipe-in-pipe branch will automatically circulate, thereby preheating the pipeline and forming hot water. This method is applicable to water-using points with high water-using frequency.

[0104] Embodiment Six:

[0105] This embodiment is basically the same as Embodiment Five, with the difference being that:

[0106] A tail valve spool is provided inside the liquid outlet valve 215. Under normal conditions, the spool of the tail valve spool abuts against the inner flow channel or the outer flow channel through an elastic member. A small channel for conducting the inner flow channel or the outer flow channel is provided on the spool, or a structure that can be deformed by pressure change to conduct the inner flow channel or the outer flow channel is provided on the spool. When the household pump 23 is started, the in-pipe branch will also automatically circulate, thereby preheating the pipeline and forming hot water. Compared with Embodiment Five, the circulation volume is relatively small and is suitable for water-using points with high water-using frequencies.

[0107] For the specific structure of the tail valve spool, please refer to patent documents such as Patent No. CN108302227B and CN207921407U.

[0108] The above embodiments are only preferred embodiments of the present invention, and do not limit the protection scope of the present invention accordingly. Therefore, all equivalent changes made according to the structure, shape, and principle of the present invention should be covered within the protection scope of the present invention.

Claims

1. A heat exchange energy-saving tube-in-tube circulation system, characterized in that: It comprises a main pipeline unit (1) and at least one entry unit (2) connected to the main pipeline unit (1); The main pipeline unit (1) comprises a water heater (11), at least one main liquid inlet pipe (12) connected to a liquid outlet end of the water heater (11), at least one main return pipe (13) connected to a return end of the water heater (11), and at least one main circulation pump (14); The entry unit (2) comprises: A tube-in-tube pipeline (21) having a first channel and a second channel; A household liquid inlet pipe (22), connected with the main liquid inlet pipe (12) and the first channel, and equipped with a water meter (27); A household pump (23) installed between the household liquid inlet pipe (22) and the pipe-in-pipe pipeline (21); an inlet return pipe (24) connecting the second channel with the liquid inlet end of the inlet pump (23); and A heat exchanger (25) having a heat medium channel connected to the main liquid inlet pipe (12) and a heating channel connected in series to the inlet return pipe (24); A circulating preheating loop is formed between the inlet pump (23), the first channel, the second channel, the inlet return pipe (24) and the heating channel, and the medium in the circulating preheating loop can be heat-conducted through the heat exchanger (25).

2. A heat exchange energy-saving tube-in-tube circulation system according to claim 1, characterized in that: The heat exchanger (25) is provided with a heat medium liquid inlet (251) and a heat medium liquid outlet (252) connected to the heat medium channel. The heat medium liquid inlet end (251) is connected to the main liquid inlet pipe (12) or the household liquid inlet pipe (22) via a heat medium liquid inlet pipe (253), and the heat medium liquid outlet end (252) is connected to the main return pipe (13) via a heat medium liquid outlet pipe (254).

3. A heat exchange energy-saving tube-in-tube circulation system according to claim 2, characterized in that: The main pipeline unit (1) comprises a plurality of main liquid inlet pipes (12) and main return pipes (13) of the same number, All the main liquid inlet pipes (12) are connected to the liquid outlet of the water heater (11) through the main liquid inlet pipe (15). All the main return pipes (13) are connected to the return end of the water heater (11) through the main return pipe (16). A plurality of household units (2) are respectively installed between corresponding main liquid inlet pipes (12) and main return pipes (13).

4. The heat exchange energy-saving tube-in-tube circulation system according to claim 1, characterized in that: The heat medium channel of the heat exchanger (25) is connected in series to the main liquid inlet pipe (12), and the main liquid inlet pipe (12) is connected to the main return pipe (13).

5. A heat exchange energy-saving tube-in-tube circulation system according to claim 4, characterized in that: The main pipeline unit (1) comprises a plurality of main liquid inlet pipes (12) and a main return pipe (13), and all the main liquid inlet pipes (12) are connected to the liquid outlet end of the water heater (11) via a main liquid inlet pipe (15); The plurality of household units (2) are respectively installed on corresponding main liquid inlet pipes (12).

6. The heat exchange energy-saving tube-in-tube circulation system according to claim 1, characterized in that: The house inlet liquid inlet pipe (22) is provided with a house inlet valve (26).

7. A heat exchange energy-saving tube-in-tube circulation system according to any one of claims 1 to 6, characterized in that: A plurality of main circulation pumps (14) are connected in parallel at the liquid outlet end of the water heater (11) or the return end of the water heater (11), and a main liquid inlet check valve (141) is connected in series at the liquid outlet end of each main circulation pump (14).

8. A heat exchange energy-saving tube-in-tube circulation system according to any one of claims 1 to 6, characterized in that: The household unit (2) further comprises a pipe-in-pipe liquid inlet valve (28), wherein the pipe-in-pipe liquid inlet valve (28) comprises a pipe-in-pipe installation end (281) connected to the pipe-in-pipe pipeline (21), a first liquid inlet installation end (282) for communicating with the first channel, and a return installation end (283) for communicating with the second channel. The household liquid inlet pipe (22) is connected to the first liquid inlet installation end (282) through the household pump (23). The reflux installation end (283) is provided with a liquid discharge check valve (284) for discharging liquid and is connected to the household reflux pipe (24).

9. A heat exchange energy-saving tube-in-tube circulation system according to claim 8, characterized in that: The tube-in-tube liquid inlet valve (28) is also provided with a second liquid inlet installation end (285) for communicating with the second channel, and the second liquid inlet installation end (285) is provided with a liquid inlet check valve (286) for liquid inlet and is connected to the household liquid inlet pipe (22).

10. The heat exchange energy-saving tube-in-tube circulation system according to claim 8, characterized in that: The pipe-in-pipe pipeline (21) comprises a pipe-in-pipe main line and at least one pipe-in-pipe branch line, the pipe-in-pipe branch line is provided with at least one pipe-in-pipe circulation end (211) and / or at least one pipe-in-pipe liquid outlet end (212), and the pipe-in-pipe circulation end (211) is provided with an electric actuator (213) for controlling the opening and closing of the first channel and the second channel; The home entry unit (2) further comprises a control module for controlling the operation of the home entry pump (23) and the electric actuator (213).

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