KR200366285Y1 - Heat source apparatus of heating and cooling system for preventing winter-sowing - Google Patents

Abstract

The present invention condenses or evaporates a gas refrigerant using heat exchange water flowing in an outdoor water circulation circuit, while supplying a heat source having a freeze protection structure configured to automatically prevent freezing of the heat exchange water in the water circulation circuit during non-circulation. The present invention relates to a heat pump supplying / heating system for a heat pump air-conditioning system having a water heat exchanger outdoors and supplying a heating and cooling heat source to an indoor unit, wherein the heat exchange water is circulated by the heat exchange water circulation pump 14 on the water circulation pipe 12. A gas refrigerant passing through the water heat exchanger 26 together with the water circulation circuit 10 and the water circulation circuit 10 while being compressed and condensed or evaporated while switching the gas refrigerant into a reverse flow depending on cooling and heating conditions. A heat exchange water temperature sensor 16 installed on the circulation circuit 20 and the water circulation pipe 12 to detect the heat exchange water temperature in the circulation pipe; In that it comprises a control unit 40 for selectively driving the heat exchanger can be water temperature detection sensor of the first freezing critical temperature is set to the temperature signal detected on the 16 previously (T ₃₎ and the number of the heat exchange as compared to the circulation pump 14 It features.

Description

Heat source supply device for heat pump air conditioning system with freeze protection structure {HEAT SOURCE APPARATUS OF HEATING AND COOLING SYSTEM FOR PREVENTING WINTER-SOWING}

The present invention relates to a heat source supply device for a heat pump cooling and heating system, and more particularly, to condense or evaporate a gas refrigerant using heat exchange water flowing in an outdoor water circulation circuit, and heat exchange the gas refrigerant with a water refrigerant. In the air-conditioning system that supplies air to the room and then heats it, the heat source supply having a freeze protection structure configured to automatically prevent freezing of heat exchange water and / or indoor water coolant in the outdoor water circulation circuit during winter operation stop and non-circulation. An apparatus and a control method thereof are provided.

In the present specification, the 'heat pump air-conditioning system' is a gas engine driven type (GHP; Gas Heat Pump), electric compression type (EHP; Electric Heat Pump) or ground source heat pumps (GSHPs), absorption type (AHP: This refers to the cooling and heating system using Absorption Heat Pump, and the GHP, EHP, GSHPs, and AHP are all equipment for cooling and heating through circulation of the heat pump cycle of the refrigerant.

As is widely known, a heat pump air-conditioning system is used in which a plurality of indoor units (cooling and air conditioning units) are connected to one outdoor heat source supply, or a plurality of outdoor heat source supplies are connected to a single indoor unit, or outdoor The heat source supply and the indoor unit are used in a 1: 1 connection.

In general, a heat pump air-conditioning system uses a 4-way valve of a gas refrigerant circulation circuit called heat pump units (GHP, EHP, GSHPs) to switch the flow of gas refrigerant in the forward and reverse directions depending on whether it is air-conditioned or not, while an outdoor heat exchanger and an indoor heat exchanger are used. The gas refrigerant is selectively evaporated or condensed to form a structure for cooling and heating the room.

In particular, the conventional heat pump air conditioning system has a structure in which an outdoor heat source supply device evaporates or condenses a gas refrigerant using an outdoor cooling fan on an outdoor heat exchanger of a gas refrigerant circulation circuit.

However, in the case of the conventional heat pump air-conditioning system that uses low specific heat air as a medium for heat exchange in the outdoor heat exchanger, the heat exchanger needs to be unnecessarily large. It has caused a problem that the heat exchange capacity by the heat exchanger is reduced, the power consumption is greatly increased, and furthermore, the cooling operation is excessive. In addition, the heating operation of the air-conditioning system at a low outside temperature also lowered the heat exchange efficiency and heating capacity and caused excessive power consumption, and furthermore, the operation itself was not possible at a temperature lower than about 10 degrees Celsius or less. Termination caused even problems.

In addition, the conventional heat pump air-conditioning system performs the cooling and cooling function of the room only through the condensation or evaporation of the refrigerant made of compressed gas (eg, R-22 and R-407c). And various restrictions such as the length of the piping of the refrigerant passage, and also have a problem in that the versatility is greatly reduced since it does not have a separate function other than the cooling and heating function.

In this regard, the present inventors have developed a heat pump air conditioning system that condenses or evaporates gas refrigerant through water heat exchange and uses the condensation or evaporative heat directly or indirectly as an indoor cooling and heating heat source.

However, when the heat pump air-conditioning system is installed in a business building or the like, it is pointed out that the risk of freezing in the outdoor water circulation circuit in the winter and the water refrigerant circulation circuit in the room at the time of operation on-time at night or on holiday is a big problem.

In response to this, the present inventors have developed a heat source supplying device for a heat pump cooling and heating system that is automatically controlled in winter to prevent freezing.

Therefore, the present invention has a water circulation circuit for condensing or evaporating a gas refrigerant through an outdoor water heat exchanger in order to use water, which has a lower specific heat than air and is less affected by outside air, as heat exchange water. And a water refrigerant circulation circuit for heat-evaporating the evaporated gas refrigerant with a water refrigerant, for example, by supplying it to the room for cooling and heating, so that the heat exchange water in the water circulation circuit and / or the water refrigerant in the room are stopped during winter operation and non-circulation. It is an object of the present invention to provide a heat source supplying device for a heat pump heating and cooling system and a control method thereof, wherein the heat exchange water is automatically circulated along a water circulation circuit according to an external temperature in order to prevent freezing by low temperature.

In addition, another object of the present invention, in the water heat exchange and water refrigerant circulation type heat pump air-conditioning system having a water refrigerant circulation indoor unit for indoor air-conditioning together with the water circulation circuit for outdoor heat exchange, In addition, it is to provide a heat source supply device for a heat pump cooling and heating system that can automatically prevent the freezing of the water refrigerant pipe and the water refrigerant circulation indoor unit extended to the water refrigerant circulation indoor unit.

1 is a schematic view showing a heat source supply device for a heat pump air conditioning system according to an embodiment of the present invention.

FIG. 2 is a flowchart illustrating an example of a method of controlling the heat source supply device of FIG. 1. FIG.

3 is a flow chart showing another example of a method of controlling the heat source supply device of FIG. 1.

Figure 4 is a block diagram showing a heat source supply device for a heat pump heating and cooling system according to another embodiment of the present invention.

5 and 6 are block diagrams illustrating examples of overall control of the heat pump cooling and heating system of the present invention.

<Code Description of Main Parts of Drawing>

10: male circulation circuit 12: male circulation piping

14: water circulation pump 16: heat exchange water detection sensor

16: heat exchange water temperature sensor 20: gas refrigerant circulation circuit

22: gas refrigerant circulation piping 23: compressor

24: 4-way valve 26: male heat exchanger

27: electronic expansion valve 28: gas-water refrigerant heat exchanger

30: water refrigerant circulation line 32: on / off valve

34: water refrigerant circulation pump 36: water refrigerant water temperature sensor

In order to achieve the above object, the present invention, while condensing or evaporating the gas refrigerant by using heat exchange water flowing in the outdoor water circulation circuit, while the heat exchange water in the water circulation circuit to prevent freezing during non-circulation automatically The present invention relates to a heat source supply device having a freeze protection structure, comprising a water heat exchanger outdoors and providing a heat source supply device for a heat pump air-conditioning system for supplying a heating / cooling heat source to an indoor unit, wherein the heat source supply device includes heat exchange water on a water circulation pipe. A water circulation circuit through which a heat exchange water is circulated by a circulation pump, and a water refrigerant circuit passing through the water heat exchanger together with the water circulation circuit, and compressing, condensing or evaporating the gas refrigerant into a reverse flow depending on cooling and heating conditions; Is installed on the water circulation pipe for detecting the water temperature of the heat exchange water in the circulation pipe And a control unit for selectively driving the circulation pump by comparing the exchange water temperature sensor and the temperature signal detected by the heat exchange water temperature sensor with a preset first freezing-wave threshold temperature. It is characterized by preventing.

The gas refrigerant circulation circuit may include a compressor, a 4-way valve, the water heat exchanger, an expansion valve, and a gas-water refrigerant (H ₂ O refrigerant) heat exchanger continuously along the gas refrigerant pipe, wherein the gas-water refrigerant The heat exchanger allows the passage of the gas refrigerant pipe and at the same time allows the passage of the water refrigerant circulation line extending to the water refrigerant circulation indoor unit, and a water refrigerant circulation pump and a water refrigerant water temperature sensor are provided on the water refrigerant circulation line. It is preferable that the controller selectively drives the water refrigerant circulation pump by comparing the temperature signal detected by the water refrigerant temperature sensor to a preset second threshold temperature.

In addition, the gas refrigerant circulation circuit has a branched passage connected to an indoor gas refrigerant circulation indoor unit while branching from the gas refrigerant circulation pipeline, and the gas refrigerant circulation circuit passes through the gas refrigerant circulation indoor unit. It is desirable to allow circulation along.

At this time, it is preferable that the water circulation circuit cools or heats the heat exchange water with geothermal heat through the heat exchanger in the ground while being buried in the ground and continuously supplies the heat exchange water to the water heat exchanger according to the operation of the water circulation pump.

Alternatively, the water circulation circuit may continuously supply heat exchange water to the water heat exchanger according to cooling by the cooling tower, heating by the boiler, and driving of the water circulation pump.

The present invention also provides an outdoor water circulation circuit, a gas refrigerant circulation circuit for condensing or evaporating a gas refrigerant using heat exchange water flowing through the water circulation circuit, and a gas-water refrigerant heat exchanger and a water refrigerant of the gas refrigerant circulation circuit. Provided is a control method of a heat pump supply unit for a heat pump air-conditioning system having a water refrigerant circulation line circulating a circulating indoor unit, and the method further comprises: keeping the operation of the heat exchange water circulation pump on the water circulation circuit stopped. And detecting the heat exchange water temperature in the water circulation circuit, comparing the heat exchange water temperature with a preset first freeze threshold temperature, and when the water temperature of the heat exchange water is lower than the first freeze threshold temperature, Operating a heat exchange water circulation pump to circulate the heat exchange water.

Here, the control method of the present invention, the step of detecting the water temperature in the water refrigerant circulation line in the state in which the operation of the water refrigerant circulation pump on the water refrigerant circulation line is stopped, and the second water temperature of the water refrigerant is set in advance Comparing with the freezing threshold temperature, and if the water temperature of the water refrigerant is lower than the second freezing threshold temperature, it is preferable to further include the step of circulating the water refrigerant by operating the water refrigerant circulation pump.

In addition, the control method of the present invention detects the water temperature of the water refrigerant circulating in the water refrigerant circulation line, and compares the water temperature of the water refrigerant with a third freeze threshold temperature, the water temperature of the water refrigerant is the third freeze threshold temperature If it is lower, the outdoor heat source supply device is driven to circulate the refrigerant in the water refrigerant circulation line, and at the same time, the on / off valve of the water refrigerant circulation indoor unit is turned on and the fan of the water refrigerant circulation indoor unit is operated to delay the freezing wave. It is desirable to prevent.

<Example>

Hereinafter, various embodiments of the present invention will be described in detail with reference to the accompanying drawings. Hereinafter, in describing the embodiments of the present invention, overlapping contents will be omitted for the sake of brevity, and in describing different embodiments, the same components throughout the present specification are the same throughout the specification. Reference numerals will be written.

1 is a block diagram showing an outdoor heat source supply apparatus according to an embodiment of the present invention with a plurality of water refrigerant circulation indoor unit connected thereto.

As shown in Fig. 1, the heat source supply device 1 of the present embodiment is a water circulation circuit 10 for supplying a heat source to a plurality of water refrigerant circulation indoor units R, commonly referred to as indoor air conditioners. And a gas refrigerant circulation circuit 20 and a water refrigerant circulation line 30, the plurality of water refrigerant circulation indoor units R having a sensor s for detecting a room temperature, the sensor s It is configured to control indoor air conditioning based on the signal detected by.

In the present embodiment, the water circulation circuit 10 includes a water circulation pipe 12 passing through an underground heat exchanger or cooling tower and a boiler buried in the ground, and the water purification pipe 12 is a water supply pipe 12a. And a recovery tube 12b. A heat exchange water circulation pump 14 is provided on the water circulation pipe 12 so as to continuously circulate the heat exchange water by driving the heat exchange water circulation pump 14.

In addition, the water circulation circuit 10 is a heat exchange water temperature sensing for detecting the water temperature (T ₁ ) of the heat exchange water on the water circulation pipe 12, preferably, the water supply pipe 12a of the water circulation pipe 12. Sensor 16, which is described in detail below, in which there is no flow of heat exchange water in the water circulation pipe 12, the water circulation circuit 10 is It is possible to predict in advance that freezing is caused by freezing of the heat exchange water.

In addition, the water circulation circuit 10 is connected to the gas refrigerant circulation circuit 20 and the gas-water refrigerant heat exchange, which is connected to the water circulation pipe 12 and the gas refrigerant of the water circulation circuit 10. The gas refrigerant circulation pipe 22 of the circulation circuit 20 is realized by simultaneously passing the outdoor water heat exchanger 26.

On the other hand, the gas refrigerant circulation circuit 20 is a structure that allows forward and reverse bidirectional flow of the gas refrigerant in a conventional heat pump unit method, for this purpose, the compressor 23, the 4-way valve along the gas refrigerant circulation pipe 22 24, the water heat exchanger 26, the electromagnetic expansion valve 27, and the gas-water refrigerant heat exchanger 28 are provided continuously. At this time, the compressor 23 and the electromagnetic expansion valve 27 is connected to the gas refrigerant circulation pipe 22 by a pipeline, the water heat exchanger 26 and the gas-water refrigerant heat exchanger 28 is It forms a structure to allow the passage of the gas refrigerant circulation pipe (22).

At the time of cooling, the gas refrigerant circulation circuit 20 compresses the gas refrigerant by the compressor 23 into a gaseous refrigerant of high temperature and high pressure, and compresses the compressed gaseous refrigerant by the four-way valve 24. Direction to the water heat exchanger (26), condensing the gas refrigerant to medium-temperature low-pressure liquid using a cold geothermal or cooling tower in the water heat exchanger (26), and condensing to the liquid state in the electronic expansion valve (27). After expanding the gas refrigerant, in the process of returning the gas refrigerant with the compressor 23, the water refrigerant (H ₂ O refrigerant) in the water refrigerant circulation line 30 to be described below through the gas-water refrigerant heat exchanger (28) To cool.

On the contrary, during heating, the four-way valve 24 reverses the flow direction of the gas refrigerant while the water heat exchanger 26 and the gas-water refrigerant heat exchanger 28 perform opposite functions. The water in the water refrigerant circulation line 30 is heated.

At this time, the water refrigerant circulation line 30 is connected to the water refrigerant circulation type indoor unit R installed in a plurality of rooms so as to be opened and closed by an on / off valve 32 in accordance with a preferred embodiment of the present invention. Meanwhile, a water refrigerant circulation pump 34 for circulating the water refrigerant is provided on its own pipe, and the water refrigerant is continuously passed through the gas-water refrigerant heat exchanger 28 and the water refrigerant circulation indoor unit R. Enables to cycle through

In addition, the water coolant circulation line 30 has a water coolant water temperature sensor 36 to detect the water temperature in its own pipeline, the water coolant water temperature sensor 36 while the heating operation is stopped in winter A function of continuously detecting the water temperature (T ₂ ) of the water refrigerant to predict the freezing of the water refrigerant circulation line 30 in accordance with the freezing of the water refrigerant (cold and hot water).

Meanwhile, the heat source supply device 1 according to the present invention receives a signal from the heat exchange water temperature sensor 16 and the water coolant water temperature sensor 36 on the water circulation circuit 10 mentioned above, and presets the first and the first signals. And a control unit 40 which transmits a driving signal to each of the heat exchange water circulation pump 14 and the water refrigerant circulation pump 34 after comparing with the two freezing wave threshold temperatures T ₃ and T ₄ . At this time, the first freeze threshold temperature T ₃ and the second freeze threshold temperature T ₄ are set differently according to various environments.

When the operation of the aforementioned heat pump air-conditioning system is stopped at night or during the winter season, the heat source supply device 1 of the present invention has a water temperature of the heat exchange water temperature sensor 16 and the water refrigerant temperature sensor 36 respectively. Detect and send the detected signal to the control unit 40, the control unit 40 compares the detected water temperature (T ₁ , T ₂ ) with a predetermined freeze threshold temperature (T ₃ , T ₄ ), respectively, When each of the water temperatures T ₁ and T ₂ is lower than the freezing threshold temperatures T ₃ and T ₄ , the heat exchange water circulation pump 14 and the water refrigerant circulation pump 34 are circulated respectively to obtain the heat exchange water and the water refrigerant. It prevents freezing and the freezing of the heat source supply device 1 and the indoor unit R in advance.

2 is a flowchart illustrating a method of controlling the heat source supply device 1 according to the previous embodiment to prevent freezing of the heat source supply device 1 as an example.

As shown in Figure 2, in order to save energy during the winter holiday or night, the operation of the heat source supply device 1 is stopped (s12). In the operation stop state, the heat exchange water temperature sensor 16 detects the water temperature of the heat exchange water in the water circulation circuit 10 (s14). Thereafter, the control unit 40 compares the detected water temperature T ₁ with a preset first freezing-wave threshold temperature T ₃ to determine whether the heat exchange water circulation pump 14 is driven (S16). If the water temperature T ₁ of the heat exchange water is lower than the first freeze threshold temperature T ₃ , the heat exchange water circulation pump 14 is driven (S16).

3 is a view for explaining another example of a method of preventing the freezing of the heat source supply device 1 by controlling the heat source supply device 1 according to the previous embodiment.

In order to save energy during the winter holiday or night, the operation of the heat source supply device is stopped (s22). In the operation stop state, the water refrigerant temperature detection sensor 36 detects the water temperature T ₂ of the water in the water refrigerant circulation line 30 (s24). Thereafter, the control unit 40 compares the detected water temperature T ₂ with a preset second freezing wave threshold temperature T ₄ to determine whether the heat exchange water circulation pump 34 is driven (S26). If the water temperature T ₂ in the water refrigerant circulation line 30 is lower than the second freeze threshold temperature T ₄ , the water refrigerant circulation pump 34 is driven to circulate the water refrigerant in the water refrigerant circulation line. To prevent freezing in advance (s28).

In addition, by comparing the water temperature (T ₅ ) of the water refrigerant in the water refrigerant circulation line 30 with the preset third freeze threshold temperature (T ₆ ), if the water temperature (T ₅ ) in the water refrigerant circulation line 30 When the temperature is lower than the third freeze threshold temperature T ₆ , the controller 40 compares the detected water temperature T ₅ with a preset third freeze threshold temperature T ₆ to determine the outdoor heat source supply device 1. By driving, the on / off valve 30 on the water refrigerant circulation line is turned on and the freeze wave is prevented by operating the fan of the water refrigerant circulation indoor unit R.

At this time, it is preferable that the control of Figs. 2 and 3 be performed at the same time, but in the present embodiment, they are divided and described for convenience of explanation.

4 is a block diagram illustrating a heat source supply device 1 of the present application together with a water refrigerant circulation indoor unit R and a gas refrigerant circulation indoor unit G connected thereto according to another embodiment of the present invention.

As shown in FIG. 4, the heat source supply device 1 according to the present embodiment is branch pipe line 22 ′ connected to a plurality of gas refrigerant circulation indoor units R while branching from the gas refrigerant pipe 22. It further includes.

Unlike the previous embodiment, the heat source supply device 1 of the present embodiment includes an electromagnetic expansion valve 27 'in each of the plurality of branch pipes 22' branched from the gas refrigerant pipe 22 instead of the water refrigerant pipe. In addition, a plurality of gas refrigerant circulating indoor unit (G) allows to heat and cool the room.

This makes it possible to use both a water refrigerant and a gas refrigerant at the same time as a refrigerant for indoor cooling and heating, so that in case of failure or malfunction of one of the gas refrigerant circulation indoor unit (G) and the water refrigerant circulation indoor unit (R), It is very advantageous in that only one can be selected so that heating and cooling can be continued.

5 is a block diagram illustrating a state in which wired / wireless communication is possible between the indoor unit R and the heat source supply device 1 by a wired / wireless communication device in the heat pump air-conditioning system to which the heat source supply device of the present invention is applied. 6 is a block diagram illustrating a state in which the central control system controls the heat source supply device 1 and the plurality of indoor units R by wired or wireless communication.

5 and 6, reference numeral R denotes an indoor unit including at least one of a gas refrigerant circulation indoor unit and a water refrigerant circulation indoor unit.

Referring to FIG. 5, it can be seen that each of the indoor unit R and the heat source supply device 1 is provided with an operation unit, and the outdoor heat exchanger is controlled by the wired / wireless communication device C via wired or wireless communication through the operation unit of the indoor unit R. have.

Referring to Figure 6, it can be seen that the central control system (M) that can control the heat source supply device and a plurality of indoor units (R) in a group mode through mutual wired and wireless communication is provided separately.

Of course, the present invention can be implemented in a variety of other forms without departing from the spirit constituting the main features. Accordingly, the above examples and embodiments are to be considered in all respects as illustrative and not restrictive, and the invention is not to be limited to the foregoing detailed description.

As described above, the heat source supply apparatus of the present invention uses the water of the groundwater, geothermal or cooling towers and boilers as heat exchange water to provide a heat source for cooling and heating the water refrigerant in the indoor unit for the heat pump cooling and heating system. Despite the suspension, it is possible to prevent the freezing of the heat source supply device and the indoor unit due to the freezing of the heat exchange water and the water refrigerant.

In addition, the present invention, as well as freezing prevention due to the freezing of the heat exchange water, further provides the effect of preventing the freezing of the water refrigerant circulating in the water refrigerant circulating indoor unit and thus the freezing wave in advance.

In addition, the heat source supply apparatus of the present invention includes an electromagnetic expansion valve in each of the plurality of branch pipes branched from the gas refrigerant pipe, not the water refrigerant pipe, so that the plurality of gas refrigerant circulation indoor units can cool and heat the room. Do it.

This makes it possible to use both air and water refrigerants for indoor air conditioning and gas refrigerant at the same time, so that if there is a failure or malfunction of one of the gas refrigerant circulation indoor units and the water refrigerant circulation indoor units, the user may select only one of them to continue heating and cooling. This allows the freezing effect of freezing to be prevented further.

Claims (4)

In the heat pump supply system for a heat pump air-conditioning system which is provided with a water heat exchanger outdoors to supply a cooling and heating heat source to the indoor unit, A water circulation circuit 10 through which the heat exchange water is circulated by the heat exchange water circulation pump 14 on the water circulation pipe 12 of the heat exchange water; A gas refrigerant circulation circuit 20 which passes through the water heat exchanger 26 together with the water circulation circuit 10 and compresses and condenses or evaporates while switching the gas refrigerant into a normal flow according to cooling and heating conditions; A heat exchange water temperature sensor (16) installed on the water circulation pipe (12) to detect a heat exchange water temperature in the circulation pipe; And a control unit 40 for selectively driving the heat exchange water circulation pump 14 by comparing the temperature signal detected by the heat exchange water temperature sensor 16 with a preset first freezing wave threshold temperature T ₃ . Heat source supply device for heat pump cooling and heating system having a freeze protection structure. The method of claim 1, The gas refrigerant circulation circuit 20 includes a compressor 23, a four-way valve 24, the water heat exchanger 26, an expansion valve 27, and a gas-water refrigerant heat exchanger along the gas refrigerant pipe 22. 28) continuously provided, The gas-water refrigerant heat exchanger 28 permits the passage of the gas refrigerant pipe 22 and at the same time allows the passage of the water refrigerant circulation line 30 extending to the water refrigerant circulation indoor unit R, A water refrigerant circulation pump 34 and a water refrigerant water temperature sensor 36 are provided on the water refrigerant circulation line 30, and the control unit 40 previously measures the temperature signal detected by the water refrigerant water temperature sensor 36. Heat source supply device for a heat pump heating and cooling system having a freeze protection structure, characterized in that for selectively driving the water refrigerant circulating pump (34) compared to the set second freeze threshold temperature (T ₄ ). The method according to claim 1 or 2, The gas refrigerant circulation circuit 20 is provided with a branch line 22 'connected to the indoor gas refrigerant circulation indoor unit G while branching from the gas refrigerant circulation pipe 22 to supply gas refrigerant. Heat source supply device for a heat pump heating and cooling system having a freeze protection structure, characterized in that the circulating indoor unit (22 ') is circulated to the gas refrigerant circulation circuit (20). The method according to claim 1 or 2, The water circulation circuit 10 cools or heats the heat exchange water with geothermal heat in the ground while being buried in the ground to continuously supply the heat exchange water to the water heat exchanger 16 according to the operation of the water circulation pump 14. Heat source supply device for a heat pump air conditioning system having a freeze protection structure, characterized in that.