Method for operating a water circulation system

Abstract

The present invention relates to a method for operating a water circulation system, comprising the following steps: providing a water circulation system consisting of an inlet pipeline (1), a return pipeline (2), a branch pipeline (3) connecting the inlet pipeline (1) and the return pipeline (2), a temperature control unit (4) connecting the inlet pipeline (1) and the return pipeline (2), a consumption end (5), a valve (6), at least one temperature sensor (60, 61, 62) and a system control; determining a first temperature, a second temperature and a reduction time; detecting the water temperature; controlling the first temperature by controlling the valve (6); and controlling the second temperature by controlling the valve (6) during the reduction time.

Description

Technical Field

[0001] The invention relates to a method for operating a water circulation system, in particular a method for operating a pipe-bound drinking water or non-drinking water system. Background Art

[0002] From the prior art, operating methods for water circulation systems are known, in which the water temperature must be kept above or below a predetermined temperature in order not to promote the growth of bacteria. The growth of bacteria, such as Pseudomonas aeruginosa or Legionella, is particularly favorable in a temperature range of 20°C to 50°C. For hygienic reasons, i.e. in order to prevent bacterial growth as much as possible, the water temperature should not be kept in this range. For comfort reasons, i.e. in order to be able to quickly reach a sufficiently high mixing temperature, the hot water temperature is usually kept at 55°C. Since the hot water pipes cannot be completely insulated, heat is constantly released from the pipes to the cooler environment, usually 8 to 10 watts per meter. The greater the temperature difference between the hot water and the environment, the greater the heat loss of the pipes. In order to reduce heat losses and thus save energy, it is permissible to reduce the hot water temperature at night. For example, the temperature can be reduced by 10°C for 8 hours. Regulatory requirements in this regard may vary from country to country. As the name suggests, the temperature is preferably reduced at night when less hot water is used or no hot water is used. However, experience shows that nighttime shutdowns are rarely or never carried out out of fear of bacteria or for convenience to avoid long waits for hot water. Therefore, most hot water circulation systems do not take advantage of the energy saving potential.

[0003] The above also applies to the cold water circulation system. Therefore, the cold water should be kept below 20℃. Since it is impossible to completely isolate the cold water pipes, the pipes will constantly absorb heat from the hotter environment. The greater the temperature difference between the cold water and the environment, the greater the heat absorption of the pipes. In order to keep the water temperature in the cold water system below 20℃ at all times, it must be cooled continuously, so energy cannot be saved. Summary of the invention

[0004] The object of the present invention is to provide a method for operating a drinking water or non-drinking water system which is more energy-efficient.

[0005] The method for operating a water circulation system according to the present invention comprises the following steps:

[0006] - Provide a water circulation system, the water circulation system comprising: at least one feed line; at least one return line; at least one branch line (strand) connecting the feed line to the return line; at least one temperature control unit, connecting the feed line to the return line, so that water can circulate according to the flow direction from the at least one feed line through the at least one branch line and the at least one return line back to the at least one feed line; at least one consumer, which is arranged along the at least one branch line and can take water out of the circulation system; at least one valve, which can change the flow rate of water in the circulation system; at least one temperature sensor, which can detect the water temperature in the pipeline section; at least one system control, which can process the data of the temperature sensor and can drive at least one valve;

[0007] - define a first temperature, define a second temperature and define a reduction time;

[0008] - detecting the water temperature with at least one temperature sensor;

[0009] - setting a first temperature by setting a first flow rate with at least one valve;

[0010] - Setting a second temperature by setting a second flow rate with at least one valve during the lowering time.

[0011] By lowering the water temperature in the system, it is possible to reduce the temperature difference between the water and the environment, thereby reducing the heat loss of the water to the environment. Such an approach allows saving energy and water without reducing comfort, while meeting strict hygiene requirements.

[0012] For example, the first temperature of the hot water circulation system can be set in the range of 50°C to 60°C. In the cold water circulation system, the first temperature can be set in the range of 10°C to 20°C. To this end, the temperature control unit (i.e., the boiler or cooling system) must cooperate with the valve to achieve the specified temperature. The higher the flow rate at the valve, the faster the water reaches the consumer end from the boiler. The flow rate required to reach the first temperature at the valve can be stored in the system control in a retrievable manner. Typically, such valves can be used to set the flow rate to a maximum of 1 liter per minute, 10 liters per minute, and a maximum of 30 liters per minute.

[0013] The second temperature can be defined directly or calculated from the first temperature and the temperature difference. For example, the temperature difference can be limited to a range of 1°C to 15°C. For example, the lowering time can be set in a range of 1 to 12 hours. The lowering time and the temperature difference can be defined by rules. For example, the temperature difference can be 10°C during a lowering time of 8 hours. As soon as the water temperature is lowered, i.e. the second temperature is set, the lowering time starts. It does not matter whether the temperature is only slightly lower than the first temperature or whether the temperature corresponds to the second temperature.

[0014] In one embodiment, the method comprises the following steps:

[0015] - define time windows;

[0016] - define thresholds;

[0017] - calculating the absolute difference between the recorded water temperature and the first temperature;

[0018] - Integrate the difference during the time window;

[0019] - setting a second temperature when the integral is less than or equal to a threshold;

[0020] - Detecting the time during which the second temperature is set;

[0021] If the integral is greater than the threshold or the total time during which the second temperature is set is greater than the lowering time, the first temperature is set.

[0022] Due to the integration of the absolute difference between the detected water temperature and the first temperature, the method can be used for hot water systems as well as for cold water systems. The time window moves with the continuous time. This means that if at any point in time it is determined (as looking backwards over the duration of the time window) that the consumption is below the threshold, the water temperature in the branch line can be reduced from this point in time or, if already reduced, kept reduced. Alternatively, the first temperature can be set if the detected water temperature is below the permitted value in the hot water system or above the permitted value in the cold water system (i.e. the permitted minimum temperature difference is exceeded). This applies to both hot water systems and cold water systems.

[0023] Compliance values ​​for the permissible temperature difference and the lowering time can be preset, and the user can adjust these values ​​individually only within the range permitted by the regulations.

[0024] Time windows can be defined as needed. For example, if water is not used within 30 minutes, the temperature can be lowered for hot water systems and raised for cold water systems. Time windows of 5 minutes, 10 minutes, 15 minutes, 30 minutes, 45 minutes, 1 hour or more can be defined.

[0025] The consumption can be determined from the detected temperature curve. In hot water systems, the measured temperature usually decreases during use, while in cold water systems, the measured temperature usually increases.

[0026] In one embodiment, the method comprises the following steps:

[0027] - determining a time period, wherein the second temperature is set only if the current time is within the time period.

[0028] The time period can be defined by a start time and an end time or by a start time and a duration. Usually, the water consumption is highest in the morning, at noon and in the evening. Therefore, several time periods in a day can be defined between the main consumption times. For example, from midnight to 6 am, from 9 am to 11 am, from 2 pm to 6 pm and from 10 pm to midnight.

[0029] In one embodiment, the time window in the boundary region of the time period is larger than the time window in the middle region thereof.

[0030] Typically, activity is more likely to occur in the border regions of the time period than in the middle regions.

[0031] For example, a time period may be set from 10pm to 6am. It is expected that there will be more activity (i.e., consumption) between 10pm and midnight and between 5am and 6am than between midnight and 5am. For example, the time window between 10pm and midnight may be 15 minutes, while the time window between midnight and 5am may be 30 minutes. Time periods may be set at any time of the day, and time windows may be graded as needed.

[0032] In one embodiment, the plan allocates several time periods in a day, the second temperature of all time periods being the same, partially different or different. For example, in a time period in which it is desired to reduce consumption, a second temperature can be predetermined which is only slightly lower than the first temperature, and in a time period in which it is desired to have almost no consumption, a second temperature can be predetermined which is even lower than the first temperature. For example, the second temperature can be 1°C, 2°C, 3°C, 5°C or 10°C lower than the first temperature. The second temperature can be set to a lower temperature higher than the rule allows (for example for comfort reasons).

[0033] In one embodiment, the method comprises the following steps:

[0034] - Record the temperature curve of the detected water temperature;

[0035] - Assigning a specific consumption to the recorded temperature curve during a time interval.

[0036] For example, a small temperature difference in a small time interval corresponds to hand washing, a higher temperature difference in a longer time period corresponds to showering, and a larger temperature difference in a longer time period corresponds to bathing. Different uses can be identified by their different temperature profiles over time. The specifications can be made at the factory or on site. For example, hand washing takes 5 to 15 seconds and consumes 2 to 10 liters of water per minute, showering takes 30 seconds to 15 minutes and consumes 8 to 20 liters of water per minute, and bathing takes 10 to 30 minutes and consumes more than 20 liters of water per minute.

[0037] In one embodiment, the method comprises the following steps:

[0038] - define at least one trigger threshold;

[0039] - Detecting a time interval (I1, I2, I3) exceeding at least one trigger threshold;

[0040] - Assignment of specific consumptions (V1, V2, V3) to recorded time intervals (I1, I2, I3).

[0041] The trigger threshold can be set as a temperature value or a temperature difference from a set temperature. The trigger threshold can also be a set temperature. Several different trigger thresholds can be defined.

[0042] In one embodiment, the method comprises the following steps:

[0043] - Scaling the integral of the water temperature based on a specific consumption.

[0044] If washing hands is only done for a short time and only a small change in temperature is detected, a second temperature that requires less energy to maintain can be maintained. When showering or bathing, this can be recognized by the temperature curve and the first temperature can be set as early as possible.

[0045] In one embodiment, the method comprises the following steps:

[0046] - Record temperature curve based on detected water temperature;

[0047] -Adjusting the time window, threshold, second temperature, reduction time or time period based on the recorded temperature profile.

[0048] For example, usage habits can be determined and used to optimize energy savings. The recorded temperature profiles can be used to create usage statistics. The above parameters can be adjusted based on usage statistics, so that a lot of energy can be saved without reducing comfort, i.e., without having to wait for hot or cold water for a long time. If it is recognized that the usage is quite high during a certain time period, the time window can be selected to be short, the threshold value to be low and the second temperature to be high. In time periods with statistically low usage, the time window can be set to be long, the threshold value to be high and the second temperature to be low.

[0049] In one embodiment, at least one valve is connected downstream of at least one consumer in the flow direction.

[0050] This ensures that in hot water systems the water temperature at the last consumer is higher than the temperature measured at the valve, and in cold water systems the water temperature at the last consumer is lower than the temperature measured at the valve.

[0051] In one embodiment, the water circulation system comprises a hot water circulation having at least one temperature control unit 4, which can supply heat to the circulation system (e.g. a boiler). Alternatively or additionally, the water circulation system comprises a cold water circulation having at least one temperature control unit (4), which can extract heat from the circulation system (e.g. a chiller).

[0052] The above-described embodiments of the method may be used in any combination as long as they do not contradict each other. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] Exemplary embodiments of the present invention are explained in more detail below using the accompanying drawings. These are only for illustration, rather than for restrictive interpretation, wherein:

[0054] Figure 1 It is a schematic diagram of the water cycle system.

[0055] Figure 2 A schematic diagram of a continuous lowering cycle according to the present invention is shown.

[0056] Figure 3 A schematic diagram of a compound reduction cycle according to the present invention is shown.

[0057] Figure 4 Shows Figure 1 Schematic diagram of the temperature profile in the branch lines of the system shown. DETAILED DESCRIPTION

[0058] Figure 1A schematic diagram of a water circulation system for performing the method according to the present invention is shown. The system comprises an inlet pipeline 1, a return pipeline 2, and two branch pipelines 3 for connecting the inlet pipeline 1 to the return pipeline 2. The system also comprises a temperature control unit 4, which connects the inlet pipeline 1 to the return pipeline 2. Water circulates in the direction from the inlet pipeline 1 to the inlet pipeline 1 via two branch pipelines 3, the return pipeline 2 and the temperature control unit 4. The system also comprises several consumer ends 5, which are arranged along the branch pipelines 3 and can take water from the circulation system. In each branch pipeline 3, a valve 6 is provided, which is located in the area of ​​the branch pipeline 3, which leads to the return pipeline 2. This means that the valve 6 is located in the end area of ​​the branch pipeline 3. By means of the valve 6, the flow rate of the water in each branch pipeline can be changed. By changing the flow rate, the temperature can be changed. The higher the flow rate, the closer the temperature of the water in the branch pipeline 3 is to the temperature of the temperature control unit. In the area of ​​the temperature control unit 4, a temperature sensor 60 is provided in the water inlet line 1, by means of which the inlet water temperature T V In the branch line 3, in the region of the valve 6, a further temperature sensor 61 is provided, with which the branch line temperature T S In the return water line 2, in the region of the temperature control unit 4, a further temperature sensor 62 is provided, by means of which the return water temperature T R . In addition, the system comprises a control unit (not shown) for each branch line or the entire system, with which the data from the temperature sensor can be processed and with which at least one valve can be actuated. A circulation pump 7 is provided in the return line 2, with which water can be transported from the branch line 3 to the temperature control unit 4 via the return line 2. A one-way valve 8 is provided between the pump 7 and the temperature control unit, which prevents water from the temperature control unit 4 from flowing back to the pump 7. The water supply line leads from the common water connection to the temperature control unit 4. In the water supply line, there is a filter 9, which can clean the tap water from the common water connection. A one-way valve 8 is set between the filter 9 and the common connection, which prevents water from the temperature control unit 4 from flowing back to the common connection.

[0059] Figure 2A schematic diagram of a continuous reduction cycle according to the present invention is shown. In the simplest case of a method for operating a water circulation system, valve 6 is set to normal operation so that a first temperature T1 is reached. During the reduction time A, valve 6 is set so that a second temperature T2 is reached. The temperature difference between the first and second temperatures can be 10°C and the reduction time is 8 hours. The reduction time can start at 10 pm and therefore end at 6 am the next day. In a further development of the method, the time window ZF is before the reduction time A. In this time window ZF, the temperature curve is used to draw conclusions about the consumption. Alternatively, a flow meter can be used to determine the consumption. If the temperature measured in the time window ZF drops below a specified value, the temperature will not be reduced. The temperature will only be reduced if the temperature measured in the time window has never been lower than the specified value. Alternatively, the difference between the first temperature and the branch line temperature measured on the time window can be integrated. If the integral exceeds a threshold value V0, the temperature will not be reduced. If the value is below the threshold value V0, the temperature will be reduced during the reduction time.

[0060] Figure 3 A schematic diagram of a compound reduction cycle according to the present invention is shown. Figure 2In contrast to the continuous reduction cycle in , the temperature reduction is interrupted as soon as the consumption is too high. The reduction time is interrupted if the temperature measured in the branch line is too low or if the temperature difference between the first temperature integrated within the time window and the strand temperature reaches or exceeds the threshold value. In the diagram shown, the consumption remains below the threshold value V0 during the time window, so the temperature is reduced from the first temperature T1 to the second temperature T2. After the first reduction time A1, the consumption exceeds the threshold value V0, whereupon the temperature is increased to the first temperature again. If the consumption falls below the threshold value again, the consumption is determined again within the time window. If the consumption is still below the threshold value, the temperature is reduced again at the end of the time window. The cycle is repeated until the sum of all reduction times equals the preset reduction time. This cycle can be repeated at will throughout the day. By integrating the temperature difference between the first temperature and the measured temperature over time, temperature changes can be taken into account. For a predetermined reduction of 10°C in 8 hours, the total integral would be 80°C h. Therefore, if the temperature reduction is smaller, the reduction time can be extended. Theoretically, this would be 16 hours at 5°C. Alternatively, the boundary area can be ignored and only the time of measuring the second temperature is considered. In another alternative, the time when the measured temperature drops below a predetermined temperature in a hot water system or exceeds a predetermined temperature in a cold water system is considered. The trigger threshold can be defined in this way, for example, ignoring smaller temperature fluctuations and considering the time of temperature reduction only when the trigger threshold is exceeded. The trigger threshold can be 0.1°C, 0.2°C, 0.4°C, 0.5°C, 1°C, 1.5°C, 2°C, 2.5°C, 3°C or higher. The trigger threshold can also be used to detect specific consumption. Measure the time exceeding the trigger threshold. Very short time (i.e., time less than 5 seconds) can be ignored. If the time is between 5 and 15 seconds, it can be concluded that, for example, someone is washing hands in a sink. For example, a time of 30 seconds to 15 minutes can indicate that a shower is being taken, while a time of 10 to 30 minutes can indicate that a bath is being taken.

[0061] In a further development, additional time periods can be defined in which reduction is fully permitted. For example, reduction is only permitted from 10 pm to 6 am of the following day. The water temperature of all branch lines is then always set to the first temperature outside this time period and can be reduced to the second temperature if permitted as described above.

[0062] Figure 4 The schematic diagram shows the temperature curve in the branch line of the system during the unit consumption V1, V2, V3. If the branch line temperature T SOnly slightly changes, it can be assigned to hand washing V1. A larger change in temperature over a longer time interval I2 can be attributed to showering V2, while a larger change in branch line temperature over a longer time interval I3 can be attributed to bathing V3. The recording of the temperature curve can be designed so that it is recorded only when the measured branch line temperature exceeds the trigger threshold, that is, when the deviation from the set temperature exceeds a certain value. Alternatively, as described above, the time exceeding the trigger threshold can be measured to determine the specific consumption V1, V2, and V3. Therefore, the time interval exceeding the trigger threshold can be used to detect specific consumption. Very short time intervals can be ignored. A short time interval indicates that you are washing your hands, a longer time interval indicates that you are showering, and a longer time interval indicates that you are bathing. Several trigger thresholds can also be determined so that the determination is not based solely on time (i.e., the length of the interval). Therefore, it can be determined which trigger threshold is exceeded in which time period. If only the first trigger threshold is exceeded, it means that you are washing your hands. If the first trigger threshold is exceeded during the first time interval and the second trigger threshold is exceeded during the second time interval, wherein the first trigger threshold is less than the second trigger threshold, and wherein the first time interval is greater than the second time interval, it means that you are showering. Thus, any number of trigger thresholds and time intervals can be combined and compared for evaluation. Preset branch line temperatures can also be used as trigger thresholds.

[0063] Reference numerals list

[0064] 1 Water inlet line T V Inlet water temperature

[0065] 2 Return pipe T S Branch line temperature

[0066] 3 branch pipeline T l , T2, T3 temperature

[0067] 4 Temperature control unit ΔT Temperature difference

[0068] 5 Consumer end T R Return water temperature

[0069] 6 Valve D l , D2 flow rate

[0070] 60 Temperature sensor ZR Time period

[0071] 61 Temperature sensor ZF Time window

[0072] 62 Temperature sensor V l , V2, V3 consumption

[0073] 7 Pump V0 Threshold

[0074] 8 Check valve A Decrease time

[0075] 9Filter A l 、A2 reduces the time segment

[0076] I1, I2, I3 time intervals.

Claims

1. A method for operating a water circulation system, comprising the following steps: - Provide a water circulation system, which includes: - at least one water inlet line (1); - at least one return line (2), - at least one branch line (3) which connects the inlet line (1) to the return line (2), - at least one temperature control unit (4) which connects the water inlet line (1) to the water return line (2), so that water can circulate in a flow direction from the at least one water inlet line through the at least one branch line and the at least one water return line back to the at least one water inlet line; - at least one consumer, which is arranged along the at least one branch line (3) and which is capable of taking water from the circulation system; - at least one valve (6) capable of varying the flow rate of water in the circulation system; - at least one temperature sensor (60, 61, 62) capable of detecting the temperature of the water in the pipe section; - at least one system control capable of processing the data of the at least one temperature sensor (60, 61, 62) and capable of actuating the at least one valve (6); - defining a first temperature (T1); - defining a second temperature (T2); - define the reduction time (A); - detecting water temperature with the at least one temperature sensor (60, 61, 62); - setting the first temperature (T1) in the pipeline section by setting a first flow rate (D1) with the at least one valve (6); - during the lowering time (A), setting a second flow rate (D2) with the at least one valve (6) to set the second temperature (T2) in the pipeline section; - define the time window (ZF); - define the minimum temperature difference; - calculating the absolute difference between the detected water temperature and the first temperature (T1); - if the absolute difference is less than or equal to the minimum temperature difference, setting the second temperature (T2); - Detecting the time for setting the second temperature (T2); - If the absolute difference is greater than the minimum temperature difference or the time for setting the second temperature (T2) is greater than the lowering time (A), then setting the first temperature (T1).

2. The method according to claim 1, comprising the steps of: - define the threshold value (V0); - integrating the absolute difference during the time window (ZF) to obtain an integral; - if the integral is less than or equal to the threshold value (V0), setting the second temperature (T2); - If the integral is greater than the threshold value (V0) or if the time for setting the second temperature (T2) is greater than the lowering time (A), the first temperature (T1) is set.

3. The method according to claim 2, comprising the steps of: - defining a time period (ZR), wherein the second temperature (T2) is set only if the current time is within the time period (ZR).

4. The method according to claim 3, wherein: The time window (ZF) in the boundary region of the time period (ZR) is larger than the time window (ZF) in the central region of the time period (ZR).

5. The method according to claim 3, wherein: Several time periods (ZR) distributed throughout the day are provided, wherein the second temperature (T2) is the same, partially different or different in all time periods (ZR).

6. The method according to claim 1, comprising the steps of: - record the temperature curve of the detected water temperature; In the recorded temperature curve, the consumptions (V1, V2, V3) are assigned to the time intervals (I1, I2, I3).

7. The method according to claim 1, comprising the steps of: - define at least one trigger threshold temperature; - detecting a time interval (I1, I2, I3) during which the at least one trigger threshold temperature is exceeded; - Assigning a specific consumption (V1, V2, V3) to the recorded time interval (I1, I2, I3).

8. The method according to claim 3, comprising the steps of: - record the temperature curve of the detected water temperature; - adjusting the time window (ZF), the threshold value (V0), the second temperature (T2), the reduction time (A) or the time period (ZR) based on the recorded temperature curve.

9. The method according to claim 1, wherein: The at least one valve (6) is connected downstream of the at least one consumer end (5) in the flow direction.

10. The method according to claim 1, wherein: The water circulation system comprises a hot water circulation having at least one temperature control unit (4), the temperature control unit (4) being capable of supplying heat to the circulation system, and / or, The water circulation system comprises a cold water circulation having at least one temperature control unit (4), and the temperature control unit (4) is capable of extracting heat from the circulation system.

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