DE102011122163A1 - Method for operating a heat pump device - Google Patents

Abstract

The invention relates to a method for operating a heat pump device, wherein the fluid is held by a fluid reservoir (2), a temperature sensor (4) detects the temperature of the fluid, and a heater (6) heats the fluid, and due to a lowering of the temperature of the Fluid at or below a minimum value, a heating of the fluid to a value above the minimum value, in particular 64 ° C, takes place. According to the invention, the value of the minimum temperature (8) is variable and depends on a period of time which has elapsed since prior heating.

Description

The present invention relates to a method for operating a heat pump device according to the preamble of patent claim 1.

Heat pump devices are used very economically because of their high thermal efficiencies and energy efficiency and used in large quantities.

The publication DE 10 2009 022 246 B4 discloses a hot water treatment device having a regulator. This regulator is provided in the lower storage area to ensure a quick recharging of water when taking off hot water. For this purpose, the temperature of the water in the reservoir is determined. This is done by a sensor. The sensor detects an integral temperature of the memory, so that conclusions can be drawn on the loading of the memory. The charging level can in turn be used to control the hot water tank. This regulation takes place, for example, in an automatic mode. In the automatic mode, the DHW cylinder charge level is reduced to a lower threshold when no tap is applied. However, if a tapping takes place, the loading level is raised again to the previous value. Thus, a heating of the water takes place when falling below a constant threshold. Depending on a subsequent or non-completed tapping process, the heating is carried out to an operating temperature or a temperature in the range above the threshold.

It has been recognized that the life and efficiency of a heat pump device or its individual components are affected by a relatively high clock frequency. Unfavorable is, for example, the frequency of switching on and off the compressor and the associated states in the connected refrigerant circuit. When using older or suboptimal storage containers falls below a threshold or a minimum temperature occur more frequently than optimally insulated hot water tanks or optimal container heat pump constellations, which in the case of suboptimal constellations, the life of the system decreases.

In the case of components which do not fit together optimally, for example a relatively small volume of water in the reservoir, the heat pump device frequently cycles. Or even in hot water tanks that are suboptimal insulated, there are creeping heat losses. As a result of the heat losses in the prior art takes place within a short period repetitive controls the heater or heat pump, whereby their life may be impaired.

The heat pump device known from the prior art always heats the water to the setpoint temperature in a normal operating state, starting from a constant switch-on value as the minimum temperature of the hot water supply. As a result, in the case of an unfavorable fluid storage heat pump apparatus constellation, frequent short operation ensues, followed by relatively short breaks. This impairs the life of the device or of the entire system.

Each start and stop of the heat pump also has a negative effect on the coefficient of performance (COP) of the heat pump. Each time the heat pump is started, it takes a while until the compressor or the refrigeration cycle works optimally. Therefore, in order to achieve the required long service life, it is generally always an objective of the system design that the heat pump starts as little as possible and runs for a long time.

It is therefore an object of the present invention to optimize the operation of a heat pump device, in particular in the hot water preparation operation, in particular with regard to life and efficiency of the entire heat pump device and its components.

The solution of the above object is achieved by a method for operating a heat pump device, in particular for hot water or for dhw. In this case, the fluid is, in particular, water, which is stored in a fluid reservoir, that is to say a hot water storage. In a first method step, the temperature of the fluid is detected by a sensor device, in particular a temperature sensor. In a second method step, the heating of the fluid is carried out to a desired temperature. As a result of the lowering of the temperature of the fluid at or below a minimum value, the fluid is heated to a value above the minimum value, in particular to the target temperature of preferably 64 ° C.

According to the invention, the value of the minimum temperature is variable and depends on a period of time which has elapsed since prior heating.

The task is thus started by means of a variable starting temperature, which each time preferably starts with a default value of 40 ° C, when the Heat pump finished the domestic water heating, and increases to the desired starting temperature, solved. In particular 56 ° C within a certain period, in particular 6 hours, are provided.

Irrespective of the respective component composition of the heat pump device, a variable temperature control method optimized to the needs and properties of the respective composition is thus provided. This leads in particular to the fact that the method can be used with optimally matched device components and with suboptimal matched device components and the largest possible period between heating periods - in compliance with comfort requirements - allows, resulting in the reliability and efficiency of all heat pump devices each on a respective Maximum value.

Thus, for example, in a normal single- or two-family house, activation of the heat pump device components for domestic hot water heating is normally sufficient every four to six hours, resulting in a significantly reduced overall control number or a significant service life extension.

According to a further preferred embodiment of the present invention, starting from a predeterminable minimum temperature in constant time intervals, an increase in the value of the minimum temperature takes place. It is also conceivable that the time periods each comprise only one second or substantially one second or any other suitable period of time. However, a calculation of the time segments is preferably carried out, this is advantageous because the individual time segments are optimally adaptable to the properties of the components of the heat pump device.

According to a further preferred embodiment of the present invention, the increase takes place in predeterminable and preferably as a function of the respective heat pump device components calculated iteration steps, in particular by constant values. The values may, for example, be between 0.01 ° C and 1 ° C, and preferably at substantially or exactly 0.1 ° C. This embodiment is advantageous because within a defined period of time, the minimum temperature can be raised to a target value for an optimal constellation for the entire system. As a result, the optimum minimum temperature can be set or adjusted for different heat pump systems.

According to a further preferred embodiment of the present invention, the value of the minimum temperature is returned to the predetermined value upon reaching a desired temperature of the fluid. In this case, it is conceivable that the period of time passed between the last reset is stored or output, whereby a change in the component behavior of the heat pump device can be determined on the basis of changing periods.

This embodiment is advantageous since it provides an automatic self-adjustment / control by the heat pump device which avoids human-machine interaction.

According to a further preferred embodiment of the present invention, the first period of time begins with the reset and the increase takes place automatically. This embodiment is advantageous since a permanent and repetitive provision or initiation of the method according to the invention is also automatically realized.

According to another preferred embodiment of the present invention, the length of the time segments is divided by the amount by dividing a predetermined maximum time period (in seconds) from a minimum start temperature (in ° C) to a minimum target temperature (in ° C) the difference of a x times, in particular 10 times, the minimum target temperature and the x-times, in particular 10 times, determines the minimum starting temperature.

This embodiment is advantageous since a determination of the respective or optimum values can be carried out simply and thus in a manner that conserves resources, in particular since the calculation has only a low complexity. Furthermore, the simple embodiment is always extremely reliable, cheap and easy to maintain.

According to a further preferred embodiment of the present invention, the predetermined period of time is between 3 and 9 hours, preferably between 4 and 8 hours and more preferably substantially or exactly 6 hours. For example, a 6 hour period may correspond to a heat pump optimum heat pump fluid storage combination heating cycle, thus allowing optimum efficiency adjustment.

According to another preferred embodiment of the present invention, the minimum starting temperature is between 30 ° C and 50 ° C, and more preferably between 30 ° C and 45 ° C, and more particularly preferably substantially or exactly 40 ° C. A temperature of 40 ° C is particularly preferred because at this temperature the fluid, especially water, is still usable for a variety of uses. For example, with 40 ° C warm water, a heating device can still be operated or a shower process can be carried out.

According to another preferred embodiment of the present invention, the minimum target temperature is a temperature between 50 ° C and 70 ° C and preferably a temperature between 50 ° C and 60 ° C and more preferably the minimum target temperature is substantially or exactly 56 ° C. This embodiment is advantageous in view of the usual, economical design and work area of a heat pump.

According to a further preferred embodiment of the present invention, the fluid in a feed device, such as a line, in particular a pipeline or a hose, the fluid reservoir is supplied and the fluid is passed from the fluid reservoir to a hot water consumer or a supply device. As hot water consumers, for example, a tap, a hot water pipe or a heating element, such as a radiator or a heating cable, are considered.

Furthermore, it is conceivable that a heat pump device is designed such that it implements or executes a method according to the aforementioned features.

Further advantages, objects and features of the present invention will be explained with reference to appended drawings in which heat pump devices or temperature profiles of heat pump devices are shown by way of example. Components of the heat pump device, which in the figures at least essentially coincide with regard to their function, can be identified by the same reference symbols, these components not having to be numbered or explained in all figures. It shows:

1 : an exemplary system for controlling the temperature of a fluid comprising a multiplicity of functionally connected devices,

2 a heating course of a known from the prior art system, and

3 : a heating course according to the invention.

In 1 is a structure of a device for heating 1 shown at least one fluid. Such a device thus comprises in addition to a receiving device 2 , which is preferably a fluid reservoir or fluid tank, a sensor device 4 for detecting the temperature of the fluid, in particular in the tank, a heat transfer system 5 , in particular a radiator, a heating device 6 , in particular a heat pump 6 , as well as other in-line components, such as a delivery device 16 , in particular a tapping point or a tap, a valve device 18 and a compressor 20 ,

Preferably, the heating takes place in the tank 2 held water when passing through the sensor device 4 detected temperature in the tank 2 is less than or equal to 56 ° C. The sensor device 4 is preferred in the bottom area of the tank 2 it is also conceivable that a plurality of sensor devices 4 are arranged distributed in the tank, in particular at different distances to the bottom of the tank 2 , In case of multiple sensor devices 4 a control device (not shown) is preferably provided, which performs an evaluation of the detected values, for example via an averaging. The heating of the water preferably ends when passing through the sensor device 4 a target temperature 9 (see. 3 ) of preferably> 56.5-57 ° C is detected or output. The aforementioned temperatures may have higher or lower values depending on other detected temperatures, in particular in a range of deviation of 0.1-3 ° C.

The outer area of the tank 2 preferably comprises 20-300 l and more preferably 60-150 l and the heat pump 6 has a heat output of preferably 1-20 kW and more preferably 5-14 kW. In case of interaction one for a specific tank 2 too big heat pump 6 ie a heat pump 6 With a too large power output, there is a very rapid heating of the outer area of the tank 2 , whereby the heat does not have enough time to go to the inside of the tank 2 penetrate. This is particularly problematic because the output of the heat pump 6 not adjustable. The of the sensor device 4 recorded target temperature 9 is thus achieved quickly and the heat pump 6 is stopped. Critical here is further that the exemplary heat pump 6 can not operate at temperatures higher than 57 ° C inlet temperature and 64 ° C outlet temperature, whereby the target temperature can not be raised. As between the interior of the tank 2 and the outer area of the tank 2 initially there is a relatively high temperature difference, there is a rapid decrease in the temperature in the outer region, whereby the sensor device 4 another falls below the critical temperature or the minimum temperature detected and as a result, a further control the heat pump 6 he follows. This is repeated within relatively short time intervals several times until the temperature is above the critical temperature or minimum temperature for a longer period of time.

In contrast, the functionality according to the invention makes possible a method and / or a device for heating 1 to provide at least one fluid, depending on the composition, ie with a specific heat pump 6 and a fluid reservoir 2 Such as a domestic hot water tank (DHW tank) or heating water tank, as well as with only suboptimal matching components, in any case, a heating of the fluid to make as far apart points in time.

This means that in the case of an unfavorable component constellation, the temperatures of the fluid can be temporarily slightly lower but the installer does not have to make any adjustments, since the variable start temperature solves the problem of too frequent launches for hot water heating.

In 2 is an example of a prior art heating curve resulting in less favorable component constellations 25 or the course of an actual temperature 7 represented The abscissa 23 indicates the time course and the ordinate 24 indicates the temperature.

By the reference numeral 8th A minimum temperature is indicated, if it falls below or reaches a heating of the water to the target temperature 9 he follows. Due to the relatively high temperature differences in the fluid region into which the heat is introduced during heating, and in the fluid region in which the heat must propagate, a first relatively steep temperature drop zone forms 21 out. The second temperature drop range 22 , which is significantly flatter, only adjusts itself to a very small temperature difference in the aforementioned areas. Because when reaching the target temperature 9 the heat pump device 1 ceases to provide heat, due to the high temperature difference of the heating process decreases 25 or the actual temperature 7 below the minimum temperature, thereby initiating further heating. This happens so often until the course of the actual temperature 7 the course of the second Temperaturabsinkbereichs 22 equivalent.

In 3 is a minimum temperature profile 8th represented, which adjusts in a method according to the invention. The minimum temperature 8th changes over time starting from a minimum starting temperature 10 towards a minimum target temperature 12 , The change can be as shown, flowing or in stages.

The minimum temperature 8th therefore changes with optimally matched components of the minimum starting temperature 8th within the desired time or standard time 13 to the minimum target temperature.

In the case of suboptimal matched components cut or meet the progress of the actual temperature 7 and the minimum temperature 8th temporally before the end of the standard time 13 (Not shown). With a high consumption of tempered water, a coincidence of the first Temperaturabsinkbereichs occurs 21 with the minimum temperature 8th , whereby a heating is initiated.

However, in the case of a lowering of the actual temperature only due to the temperature difference between the water area in which the heat propagates and the water area into which the heat is introduced 7 and / or small withdrawals tempered water is preferably a coincidence of the second Temperaturabsinkbereichs 22 with the curve of the minimum temperature 8th , This thus takes place as a function of the respective component constellation, whereby in each case a response frequency adapted or reduced to the respective component constellation is set. The minimum temperature 8th is preferred if the actual temperature 7 the target temperature 9 corresponds to the minimum starting temperature 10 reset.

LIST OF REFERENCE NUMBERS

1

Device for heating

2

recording device

4

sensor device

5

Heat transfer system

6

heater

7

Actual temperature

8th

minimum temperature

9

target temperature

10

Minimum starting temperature

12

Minimum target temperature

13

standard time

14

feeding

16

Providing device

18

valve means

20

compressor

21

First temperature drop range

22

Second temperature drop range

23

abscissa

24

ordinate

25

heat curve

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 102009022246 B4 [0003]

Claims (10)

Method for operating a heat pump device ( 1 ), wherein a fluid in a fluid reservoir ( 2 ), at least one temperature sensor ( 4 ) detects the temperature of the fluid, a heating device ( 6 ) heats the fluid to a predetermined temperature setpoint, and as a result of lowering the temperature of the fluid at or below a minimum value, the fluid is heated to a value above the minimum value, characterized in that the value of the minimum temperature ( 8th ) is variable and depends on a period of time that has elapsed since prior heating. Method for operating a heat pump device ( 1 ) according to claim 1, characterized in that starting from a predeterminable minimum temperature in constant time intervals an increase in the value of the minimum temperature ( 8th ) he follows. Method for operating a heat pump device ( 1 ) according to claim 2, characterized in that the increase, in particular by constant values, takes place in predefinable iteration steps. Method for operating a heat pump device ( 1 ) according to claim 3, characterized in that the value of the minimum temperature ( 8th ) is reset to the predetermined value when a desired temperature of the fluid is reached. Method for operating a heat pump device ( 1 ) according to claim 4, characterized in that with the reset of the first period begins to run and the increase takes place automatically. Method for operating a heat pump device ( 1 ) according to one of the preceding claims, characterized in that the length of the time segments is determined by dividing a predetermined maximum time period (in seconds) starting from a minimum starting temperature (in C °) ( 10 ) a minimum target temperature (in C °) ( 12 ), by the amount of the difference of x times, in particular 10 times, the minimum target temperature ( 12 ) and x times, the minimum starting temperature ( 10 ) is determined. Method for operating a heat pump device ( 1 ) according to claim 5, characterized in that the predetermined period is between 3 and 9 hours, preferably between 4 and 8 hours and more preferably 6 hours. Method for operating a heat pump device ( 1 ) according to claim 5 or 6, characterized in that the minimum starting temperature ( 10 ) is a temperature between 30 ° C and 50 ° C and is preferably between 35 ° C and 45 ° C, and more preferably 40 ° C. Method for operating a heat pump device ( 1 ) according to one of claims 5, 6 or 7, characterized in that the minimum target temperature ( 12 ) is a temperature between 50 ° C and 70 ° C, and is preferably between 50 ° C and 60 ° C, and more preferably 56 ° C. Method for operating a heat pump device ( 1 ) according to one of the preceding claims, characterized in that the fluid in a feed device ( 14 ) the fluid reservoir ( 2 ) and the fluid in a supply device ( 16 ) from the fluid reservoir ( 2 ) to a hot water consumer ( 16 ).

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