1. A heat pump exhaust temperature adjustment method, comprising:

s1, collecting exhaust temperature T1, effluent temperature T2 and environment temperature T3 of a heat pump unit;

s2, the heat pump unit enters a starting stage;

s3, judging whether the heat pump unit is in a low-environment-temperature high-water-temperature section or not, if so, executing first starting adjustment of a main valve by a main electronic expansion valve (7) after a compressor (1) is started, and executing first starting adjustment of an auxiliary valve by an auxiliary electronic expansion valve (5); if not, the main electronic expansion valve (7) executes the second starting adjustment of the main valve after the compressor (1) is started, and the auxiliary electronic expansion valve (5) executes the second starting adjustment of the auxiliary valve;

s4, the heat pump unit enters an operation stage;

s5, if the exhaust temperature T1 is lower than a first preset temperature, the opening degree of the auxiliary electronic expansion valve (5) is controlled according to preset exhaust superheat degree logic, and the opening degree of the main electronic expansion valve (7) is controlled according to preset return air superheat degree logic; if the exhaust temperature T1 is greater than or equal to a first preset temperature and less than a second preset temperature, the main electronic expansion valve (7) and the auxiliary electronic expansion valve (5) execute a first exhaust suppression stage; if the exhaust temperature T1 is greater than or equal to a second preset temperature and less than a third preset temperature, the main electronic expansion valve (7) and the auxiliary electronic expansion valve (5) execute a second exhaust suppression stage; and if the exhaust temperature T1 is greater than or equal to a third preset temperature, performing shutdown protection on the heat pump unit.

2. The heat pump exhaust temperature adjusting method according to claim 1, wherein if the outlet water temperature T2 is greater than a fourth preset temperature and the ambient temperature T3 is less than a fifth preset temperature, the heat pump unit is in a low ambient temperature high outlet water temperature section; if not, the heat pump unit is not in the low-environment-temperature high-water-outlet-temperature section.

3. The heat pump exhaust temperature adjustment method according to claim 1, wherein the main valve first actuation adjustment is: and the main electronic expansion valve (7) is switched to adjust the opening according to a normal initial opening logical table after maintaining the initial opening for a first preset time, and is switched to control the opening according to the preset return air superheat degree logical table after a second preset time.

4. The heat pump exhaust gas temperature regulation method of claim 1, wherein the auxiliary valve first actuation regulation is: and after maintaining the initial opening degree for a third preset time, the auxiliary electronic expansion valve (5) is switched to control the opening degree according to the preset exhaust superheat degree logic.

5. The heat pump exhaust gas temperature regulation method according to claim 4, wherein the initial opening degree of the auxiliary electronic expansion valve (5) is P, P being 50K1-120, where K1 is (0.02T3^3-0.2T3^2+7T3^2-50)/(-0.06T2^2+4.7T 2-40).

6. The heat pump exhaust temperature adjustment method according to claim 1, wherein the main valve second actuation adjustment is: and the main electronic expansion valve (7) adjusts the opening according to a normal initial opening logic table, and after a fourth preset time, the opening is changed to be controlled according to the preset return air superheat degree logic.

7. The heat pump exhaust gas temperature regulation method of claim 1, wherein the secondary valve second actuation regulation is: and after maintaining the initial opening degree for a fifth preset time, the auxiliary electronic expansion valve (5) is switched to control the opening degree according to the preset exhaust superheat degree logic.

8. The heat pump exhaust gas temperature adjusting method according to claim 1, characterized in that in the first exhaust gas suppression phase, the main electronic expansion valve (7) controls the opening degree according to the preset return gas superheat degree logic, but the opening degree is not allowed to be increased; the auxiliary electronic expansion valve (5) controls the opening degree according to the exhaust superheat degree inhibiting logic, wherein the exhaust superheat degree target value in the exhaust superheat degree inhibiting logic is the sum of the exhaust superheat degree target value and a preset value in the preset exhaust superheat degree logic.

9. The heat pump exhaust gas temperature adjusting method according to claim 1, wherein the second exhaust gas suppression stage is divided into a first stage and a second stage, and if the exhaust gas temperature T1 is greater than or equal to a second preset temperature and less than a sixth preset temperature, the main electronic expansion valve (7) and the auxiliary electronic expansion valve (5) execute the first stage; and if the exhaust temperature T1 is greater than or equal to a sixth preset temperature and less than a third preset temperature, the main electronic expansion valve (7) and the auxiliary electronic expansion valve (5) execute the second stage.

10. The heat pump exhaust gas temperature adjusting method according to claim 9, wherein in the first stage, the main electronic expansion valve (7) controls the opening degree according to the preset return gas superheat degree logic, but the opening degree is not allowed to be increased; the opening degree of the auxiliary electronic expansion valve (5) is increased by a first preset opening degree every sixth preset time;

in the second stage, the opening degree of the main electronic expansion valve (7) is reduced by a second preset opening degree every seventh preset time, and the opening degree of the auxiliary electronic expansion valve (5) is increased by a third preset opening degree every eighth preset time.

Background

At present, in the air source heat pump industry, if a higher outlet water temperature is operated at a lower environmental temperature, the phenomenon of overhigh exhaust temperature is very easy to occur in a heat pump unit due to overhigh compression ratio, so that the heat pump system is triggered to carry out exhaust protection. At present, the existing scheme for restraining the overhigh exhaust temperature under the condition is to directly open a main valve or an auxiliary valve, but the method cannot effectively reduce the exhaust temperature, so that the fluctuation capability of the operating state of the heat pump system is poor, and the compressor is easy to cause overheat protection, thereby causing the continuous liquid return or the burnout of the compressor.

Disclosure of Invention

The invention aims to provide a heat pump exhaust temperature adjusting method, which can effectively reduce the exhaust temperature and ensure the stable operation of a heat pump unit.

A heat pump exhaust temperature conditioning method comprising:

s1, collecting exhaust temperature T1, effluent temperature T2 and environment temperature T3 of a heat pump unit;

s2, the heat pump unit enters a starting stage;

s3, judging whether the heat pump unit is in a low-environment-temperature high-water-temperature section or not, if so, executing first starting adjustment of a main valve by a main electronic expansion valve after the compressor is started, and executing first starting adjustment of an auxiliary valve by an auxiliary electronic expansion valve; if not, the main electronic expansion valve executes the second starting adjustment of the main valve after the compressor is started, and the auxiliary electronic expansion valve executes the second starting adjustment of the auxiliary valve;

s4, the heat pump unit enters an operation stage;

s5, if the exhaust temperature T1 is lower than a first preset temperature, the auxiliary electronic expansion valve logically controls the opening degree according to a preset exhaust superheat degree, and the main electronic expansion valve logically controls the opening degree according to a preset return air superheat degree; if the exhaust temperature T1 is greater than or equal to a first preset temperature and less than a second preset temperature, the main electronic expansion valve and the auxiliary electronic expansion valve execute a first exhaust suppression stage; if the exhaust temperature T1 is greater than or equal to a second preset temperature and less than a third preset temperature, the main electronic expansion valve and the auxiliary electronic expansion valve execute a second exhaust suppression stage; and if the exhaust temperature T1 is greater than or equal to a third preset temperature, performing shutdown protection on the heat pump unit.

As a preferable scheme of the heat pump exhaust temperature adjusting method, if the outlet water temperature T2 is greater than a fourth preset temperature and the environment temperature T3 is less than a fifth preset temperature, the heat pump unit is in a low-environment-temperature high-outlet-water-temperature section; if not, the heat pump unit is not in the low-environment-temperature high-water-outlet-temperature section.

As a preferable mode of the heat pump exhaust temperature adjusting method, the first actuation adjustment of the main valve is: and after the main electronic expansion valve maintains the initial opening degree for the first preset time, the opening degree is adjusted according to a normal initial opening degree logic table, and after the second preset time, the opening degree is controlled according to the preset return air superheat degree logic.

As a preferable scheme of the heat pump exhaust temperature adjusting method, the auxiliary valve first start adjustment is that: and after maintaining the initial opening degree for a third preset time, the auxiliary electronic expansion valve is switched to control the opening degree according to the preset exhaust superheat degree logic.

As a preferable scheme of the heat pump exhaust temperature adjusting method, the initial opening degree of the auxiliary electronic expansion valve is P, P is 50K1-120, wherein K1 is (0.02T3^3-0.2T3^2+7T3^2-50)/(-0.06T2^2+4.7T 2-40).

As a preferable scheme of the heat pump exhaust temperature adjusting method, the second starting adjustment of the main valve is as follows: and the main electronic expansion valve adjusts the opening according to the normal initial opening logical table, and after the fourth preset time, the opening is changed to be controlled according to the preset return air superheat degree logical table.

As a preferable scheme of the heat pump exhaust temperature adjusting method, the second starting adjustment of the auxiliary valve is as follows: and after maintaining the initial opening degree for a fifth preset time, the auxiliary electronic expansion valve is switched to control the opening degree according to the preset exhaust superheat degree logic.

As a preferable scheme of the heat pump exhaust temperature adjusting method, in the first exhaust suppression stage, the main electronic expansion valve controls the opening according to the preset return air superheat degree logic, but the opening is not allowed to be increased; the auxiliary electronic expansion valve controls the opening degree according to the exhaust superheat degree inhibiting logic, wherein the exhaust superheat degree target value in the exhaust superheat degree inhibiting logic is the sum of the exhaust superheat degree target value and a preset value in the preset exhaust superheat degree logic.

As a preferable scheme of the heat pump exhaust gas temperature adjusting method, the second exhaust gas suppression stage is divided into a first stage and a second stage, and if the exhaust gas temperature T1 is greater than or equal to a second preset temperature and less than a sixth preset temperature, the main electronic expansion valve and the auxiliary electronic expansion valve execute the first stage; and if the exhaust temperature T1 is greater than or equal to a sixth preset temperature and less than a third preset temperature, the main electronic expansion valve and the auxiliary electronic expansion valve execute the second stage.

As a preferable scheme of the heat pump exhaust temperature adjusting method, in the first stage, the main electronic expansion valve controls the opening degree according to the preset return air superheat degree logic, but the opening degree is not allowed to be increased; the opening degree of the auxiliary electronic expansion valve is increased by a first preset opening degree every sixth preset time;

in the second stage, the opening degree of the main electronic expansion valve is closed by a second preset opening degree every seventh preset time, and the opening degree of the auxiliary electronic expansion valve is increased by a third preset opening degree every eighth preset time.

The invention has the beneficial effects that:

the invention provides a heat pump exhaust temperature adjusting method, wherein a heat pump unit judges whether the heat pump unit is in a low-environment-temperature high-water-temperature section or not before starting, if so, a main electronic expansion valve executes first starting adjustment of a main valve, and an auxiliary electronic expansion valve executes first starting adjustment of an auxiliary valve. After the heat pump unit enters the operation stage, the auxiliary electronic expansion valve and the main electronic expansion valve perform different opening degree adjustments according to different ranges of exhaust temperature T1, so that the heat pump unit operates stably, the fluctuation capacity of the operation state of the heat pump unit is improved, and the exhaust temperature can be effectively reduced.

Drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings used in the description of the embodiments of the present invention will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the contents of the embodiments of the present invention and the drawings without creative efforts.

FIG. 1 is a flow chart of a method of regulating the temperature of a heat pump exhaust according to an embodiment of the present invention;

fig. 2 is a schematic structural diagram of a heat pump system according to an embodiment of the present invention.

In the figure:

1. a compressor; 2. a four-way valve; 3. a condenser; 4. an economizer; 5. an auxiliary electronic expansion valve; 6. a reservoir; 7. a main electronic expansion valve; 8. an evaporator; 9. a gas-liquid separator.

Detailed Description

In order to make the technical problems solved, technical solutions adopted and technical effects achieved by the present invention clearer, the technical solutions of the embodiments of the present invention will be described in further detail below with reference to the accompanying drawings, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

In the description of the present invention, unless expressly stated or limited otherwise, the terms "connected," "connected," and "fixed" are to be construed broadly, e.g., as meaning permanently connected, removably connected, or integral to one another; can be mechanically or electrically connected; either directly or indirectly through intervening media, either internally or in any other relationship. The specific meanings of the above terms in the present invention can be understood in specific cases to those skilled in the art.

In the present invention, unless otherwise expressly stated or limited, "above" or "below" a first feature means that the first and second features are in direct contact, or that the first and second features are not in direct contact but are in contact with each other via another feature therebetween. Also, the first feature being "on," "above" and "over" the second feature includes the first feature being directly on and obliquely above the second feature, or merely indicating that the first feature is at a higher level than the second feature. A first feature being "under," "below," and "beneath" a second feature includes the first feature being directly under and obliquely below the second feature, or simply meaning that the first feature is at a lesser elevation than the second feature.

The technical scheme of the heat pump exhaust temperature adjusting method provided by the invention is further explained by the specific implementation mode.

The embodiment provides a heat pump exhaust temperature adjusting method, as shown in fig. 1, the heat pump exhaust temperature adjusting method includes the following steps:

s1, collecting exhaust temperature T1, effluent temperature T2 and environment temperature T3 of a heat pump unit.

That is, before the heat pump unit is started, the exhaust temperature T1, the effluent temperature T2 and the ambient temperature T3 of the heat pump unit are collected, so that the temperature section where the heat pump unit is located can be conveniently judged. It should be noted that, after the heat pump unit is started, the exhaust temperature T1, the outlet water temperature T2 and the ambient temperature T3 of the heat pump unit are continuously detected, so as to determine the temperature section where the heat pump unit is located in real time.

S2, the heat pump unit enters a starting stage.

That is, the heat pump unit enters the startup phase and is ready to start. Preferably, the main electronic expansion valve 7 and the auxiliary electronic expansion valve 5 are both reset before the heat pump unit enters the start-up phase (before the compressor 1 is turned on).

S3, judging whether the heat pump unit is in a low-environment-temperature high-water-temperature section or not, if so, executing first starting adjustment of a main valve by a main electronic expansion valve 7 after the compressor 1 is started, and executing first starting adjustment of an auxiliary valve by an auxiliary electronic expansion valve 5; if not, after the compressor 1 is started, the main electronic expansion valve 7 executes the second starting adjustment of the main valve, and the auxiliary electronic expansion valve 5 executes the second starting adjustment of the auxiliary valve.

It should be noted that, if the effluent temperature T2 is greater than the fourth preset temperature and the ambient temperature T3 is less than the fifth preset temperature, the heat pump unit is in the low ambient temperature and high effluent temperature section; if not, the heat pump unit is not in the low-environment-temperature high-water-outlet-temperature section. In this embodiment, the fourth preset temperature is set to 50 ℃ and the fifth preset temperature is set to-10 ℃. That is, if the leaving water temperature T2 is higher than 50 ℃ and the environmental temperature T3 is lower than-10 ℃, the heat pump unit is in the low-environmental-temperature high-leaving-water-temperature section.

Preferably, the main valve first actuation adjustment is: the main electronic expansion valve 7 is switched to adjust the opening according to a normal initial opening logical table after maintaining the initial opening for a first preset time, and is switched to control the opening according to a preset return air superheat degree logical table after a second preset time. It should be noted that the initial opening degree of the main electronic expansion valve 7 is 350 steps, and it can be understood that the steps are units of the opening degrees of the main electronic expansion valve 7 and the auxiliary electronic expansion valve 5 in this embodiment, and those skilled in the art can set the specific opening degrees according to actual situations, and the specific opening degrees are not described herein again. It can be understood that the normal initial opening degree logic table and the preset return air superheat degree logic are both preset opening degree adjusting logics, and opening degree adjustment is performed according to the logics, which is not described herein again. In this embodiment, the first preset time is 90 seconds, and the second preset time is 30 seconds, that is, the main electronic expansion valve 7 maintains the initial opening of 350 steps for 90 seconds, then turns to adjust the opening according to the normal initial opening logic table, and after 30 seconds, turns to control the opening according to the preset back air superheat logic.

In this embodiment, the first actuation adjustment of the auxiliary valve is: and the auxiliary electronic expansion valve 5 maintains the initial opening degree for a third preset time and then turns to control the opening degree according to a preset exhaust superheat degree logic. It should be noted that the initial opening of the auxiliary electronic expansion valve 5 is P, where P is 50K1-120, where K1 is (0.02T3^3-0.2T3^2+7T3^2-50)/(-0.06T2^2+4.7T 2-40). It can be understood that the preset exhaust superheat degree logic is preset opening degree adjusting logic, and opening degree adjustment is performed according to the preset opening degree adjusting logic, which is not described herein again. In this embodiment, the third preset time is 30 seconds, that is, the opening of the auxiliary electronic expansion valve 5 is controlled according to the preset exhaust superheat logic after maintaining the initial opening for 30 seconds.

Specifically, the main valve second actuation adjustment is: and the main electronic expansion valve 7 adjusts the opening according to the normal initial opening logic table, and after the fourth preset time, the opening is changed to be controlled according to the preset return air superheat logic. It should be noted that the preset return air superheat degree logic is an opening degree adjusting logic that is set in advance, and here, opening degree adjustment is performed according to the logic, which is not described herein again. In this embodiment, the fourth preset time is 90 seconds, that is, the main electronic expansion valve 7 adjusts the opening according to the normal initial opening logic table, and after 90 seconds, the opening is changed to control according to the preset back air superheat logic.

The second start adjustment of the auxiliary valve is: and after maintaining the initial opening degree for the fifth preset time, the auxiliary electronic expansion valve 5 is switched to control the opening degree according to the preset exhaust superheat degree logic. In this embodiment, the fifth preset time is 90 seconds, that is, the auxiliary electronic expansion valve 5 maintains the calculated initial opening degree first, and after 90 seconds, the opening degree is changed to the preset exhaust superheat degree logic control opening degree.

S4, the heat pump unit enters an operation stage.

That is, the heat pump unit enters the run phase after the start phase is finished.

And S51, if the exhaust temperature T1 is lower than a first preset temperature, the auxiliary electronic expansion valve 5 controls the opening degree according to a preset exhaust superheat degree logic, and the main electronic expansion valve 7 controls the opening degree according to a preset return air superheat degree logic.

In the present embodiment, the first preset temperature is 95 ℃, that is, if the exhaust temperature T1 is less than 95 ℃, the auxiliary electronic expansion valve 5 controls the opening degree according to the preset exhaust superheat degree logic, and the main electronic expansion valve 7 controls the opening degree according to the preset return superheat degree logic.

S52, if the exhaust temperature T1 is greater than or equal to the first preset temperature and less than the second preset temperature, the main electronic expansion valve 7 and the auxiliary electronic expansion valve 5 execute the first exhaust suppression stage.

In the present embodiment, the second preset temperature is 105 ℃, that is, the discharge temperature T1 is greater than or equal to 95 ℃ and less than 105 ℃, and the main electronic expansion valve 7 and the auxiliary electronic expansion valve 5 perform the first discharge suppression stage. Specifically, in the first exhaust suppression phase, the main electronic expansion valve 7 controls the opening according to the preset back air superheat degree logic, but the opening is not allowed to be increased; the auxiliary electronic expansion valve 5 controls the opening degree according to the exhaust superheat degree suppression logic, wherein the exhaust superheat degree target value in the exhaust superheat degree suppression logic is the exhaust superheat degree target value in the preset exhaust superheat degree logic plus a preset value. It should be noted that the preset exhaust superheat degree logic is preset exhaust gas regulation logic with a target exhaust superheat degree value, and the preset value is 3 ℃, that is, here, the opening degree of the auxiliary electronic expansion valve 5 is regulated according to the preset exhaust superheat degree logic and by adding 3 ℃ to the target exhaust superheat degree value in the exhaust superheat degree suppression logic according to the control opening degree size in the exhaust superheat degree logic.

In step S52, if the exhaust temperature T1 is less than 95 ℃, the heat pump unit proceeds to step S51.

S53, if the exhaust temperature T1 is greater than or equal to the second preset temperature and less than the third preset temperature, the main electronic expansion valve 7 and the auxiliary electronic expansion valve 5 execute the second exhaust suppression stage.

In the present embodiment, the third preset temperature is 118 ℃, that is, the exhaust temperature T1 is greater than or equal to 105 ℃ and less than 118 ℃, and the main electronic expansion valve 7 and the auxiliary electronic expansion valve 5 perform the second exhaust suppression stage. Specifically, the second exhaust suppression stage is divided into a first stage and a second stage, and if the exhaust temperature T1 is greater than or equal to a second preset temperature and less than a sixth preset temperature, the main electronic expansion valve 7 and the auxiliary electronic expansion valve 5 execute the first stage; if the exhaust temperature T1 is greater than or equal to the sixth preset temperature and less than the third preset temperature, the main electronic expansion valve 7 and the auxiliary electronic expansion valve 5 execute the second stage.

Specifically, in the first stage, the main electronic expansion valve 7 controls the opening degree according to the preset return air superheat degree logic, but the opening degree is not allowed to be increased; the opening degree of the auxiliary electronic expansion valve 5 is increased by the first preset opening degree every sixth preset time. In the second stage, the opening degree of the main electronic expansion valve 7 is decreased by the second preset opening degree every seventh preset time, and the opening degree of the auxiliary electronic expansion valve 5 is increased by the third preset opening degree every eighth preset time.

In this embodiment, the sixth preset temperature is 110 ℃, the sixth preset time is 30 seconds, the first preset opening degree is 5% of the maximum opening degree of the auxiliary electronic expansion valve 5, the seventh preset time is 60 seconds, the second preset opening degree is 1 step of the opening degree of the main electronic expansion valve 7, the eighth preset time is 30 seconds, and the third preset opening degree is 10% of the maximum opening degree of the auxiliary electronic expansion valve 5.

That is, if the exhaust temperature T1 is greater than or equal to 105 ℃ and less than 110 ℃, the main electronic expansion valve 7 and the auxiliary electronic expansion valve 5 execute the first stage, that is, the main electronic expansion valve 7 controls the opening according to the preset back air superheat degree logic, but the opening is not allowed to be increased; and the opening degree of the auxiliary electronic expansion valve 5 is increased by 5% of the maximum opening degree every 30 seconds.

If the exhaust temperature T1 is greater than or equal to 110 ℃ and less than 118 ℃, the main electronic expansion valve 7 and the auxiliary electronic expansion valve 5 perform the second stage, i.e., the opening degree of the main electronic expansion valve 7 is reduced by 1 step every 60 seconds; and the opening degree of the auxiliary electronic expansion valve 5 is increased by 10% of the maximum opening degree every 30 seconds.

In step S53, if the exhaust gas temperature T1 is less than 105 ℃, the heat pump unit proceeds to step S52.

S54, if the exhaust temperature T1 is greater than or equal to a third preset temperature, the heat pump unit is subjected to shutdown protection.

That is, if the exhaust temperature T1 is greater than or equal to 118 ℃, the heat pump unit performs shutdown protection.

The embodiment also provides a heat pump system, and the method for adjusting the exhaust temperature of the heat pump provided by the technical scheme can adjust the exhaust temperature of the heat pump system. As shown in fig. 2, the heat pump system includes a compressor 1, a four-way valve 2, a condenser 3, an economizer 4, an auxiliary electronic expansion valve 5, a liquid reservoir 6, a main electronic expansion valve 7, an evaporator 8, and a gas-liquid separator 9, wherein the compressor 1 is connected to the condenser 3 through the four-way valve 2, the condenser 3 is provided with a water inlet and a water outlet, and the circulating water exchanges heat with the condenser 3 to provide outlet water at a temperature required by the outside. An economizer 4, an auxiliary electronic expansion valve 5, a liquid storage device 6 and a main electronic expansion valve 7 are sequentially connected between the condenser 3 and the evaporator 8, the main electronic expansion valve 7 is connected with a gas-liquid separator 9 through a four-way valve 2, the gas-liquid separator 9 is connected with the compressor 1, and the components jointly form a heat pump system.

It should be understood that the above-described embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention. Numerous obvious variations, adaptations and substitutions will occur to those skilled in the art without departing from the scope of the invention. And are neither required nor exhaustive of all embodiments. Any modification, equivalent replacement, and improvement made within the spirit and principle of the present invention should be included in the protection scope of the claims of the present invention.

It is noted that reference throughout this specification to "some embodiments," "other embodiments," or the like, means that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, the schematic representations of the terms used above do not necessarily refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.