• 专利附录
  • 专利说明
  • 权利要求
  • 类似技术
  • 同族专利
  • 引用文献
  • 法律状态
  • 优先权
    • 专利摘要:
    Summary The invention relates to a method for controlling defrosting of a heat exchanger 1. The method comprises determining the efficiency of the heat exchanger ij, before considering the efficiency of the heat exchanger thereafter and then assessing whether the heat exchanger needs to be defrosted. The invention also relates to a system for a heat exchanger 1. The system for the heat exchanger comprises food equipment 11 in connection with the heat exchanger 1, the food equipment 11 being adapted to collect data for the efficiency of the heat exchanger, which data is intended to be used in a calculation unit 12 for calculating the heat exchanger's efficiency. The calculation unit 12 is adapted to transmit an efficiency signal Su. The system also comprises an evaluation unit 14 adapted to receive the efficiency signal S and to ask if the heat exchanger needs to be defrosted based on the efficiency
    公开号:SE1150905A1
    申请号:SE1150905
    申请日:2011-09-30
    公开日:2013-03-31
    发明作者:Christian Halvarsson；Erik Brisenheim
    申请人:Voltair Systems Ab；
    IPC主号:
    专利说明:

    Title Method and system for controlling defrosting of a heat exchanger Field of the Invention The present invention relates to a method for controlling defrosting of a heat exchanger and a system for a heat exchanger according to the preambles of the independent patent claims.
    Background of the invention Heat exchangers can be installed in ventilation systems in properties such as residential buildings and properties where commercial activities are conducted. The heat exchanger aims to utilize energy in air that is led out of properties, so-called exhaust air, and to utilize energy in the air that is led into the property, so-called supply air. Usually a heat exchanger is built up of an exhaust air duct, a supply air duct, a heat exchanging unit for transferring energy between the two ducts, air filters, batteries and fans to lead out / in the exhaust air and the supply air, respectively. In addition, there may be pre- and post-heaters arranged in connection with the heat exchanger. The heat exchanger may need to work at different times of the day; for a property where commercial activities are conducted, the ventilation system is running during the day, when it is a residential building, the largest use of the ventilation system and thus the heat exchanger for a couple of hours in the morning and during the evening / afternoon, however, the ventilation system in a residential building needs to be more or less active throughout the day.
    The heat exchanger can be installed in a property in a climate where warmer air is desired inside the property than outside during the winter. As it is outdoor temperatures in winter that lead to ice or frost formation, it may be necessary to defrost the heat exchanger. Usually this only needs to be done in residential buildings where the heat exchanger is in operation around the clock. In a property where commercial activities are conducted, defrosting can take place automatically when the heat exchanger is not in operation, ie. usually at night which is the time when no commercial activity is conducted.
    Eli commonly used to control defrosting for heat exchangers has been aft this occurs at regular time intervals during the periods when the outdoor temperature is below 0 ° C or thereabouts. Another way to control the defrosting of heat exchangers can be to feed the moisture content into the exhaust air or supply air in combination with temperature measurements. Another common salt is to calculate the pressure drop across the heat exchanger. A normal method of defrosting a heat exchanger takes place by driving the exhaust air at a higher speed frequency or by using so-called pre- / post-heaters. Another common way may be to use a so-called "bypass" function.
    Defrosting heat exchangers regularly Over time, this is most appropriate for heat exchangers made of metal or similar, as these become ice-covered when the outdoor temperature is below 0 ° C or around. Exactly at what temperature ice is formed also depends on the humidity level of the air. However, it has been shown that it is not mediocre to regularly defrost a heat exchanger made of other materials, such as plastic. Nor have other accepted methods for assessing whether the heat exchanger needs to be defrosted proved to be reliable. As the outdoor temperature is below 0 ° C, ice does not form on a plastic heat exchanger, but rather the freezing takes place in the form of layers of frost or silo.
    The freezing also depends on the size of the heat exchanger. For a large heat exchanger, freezing takes longer than a smaller one. Thus, a smaller heat exchanger may need to be defrosted more often than a larger one.
    There are different types of heat exchangers depending on the system in which the heat exchanger is to be used. In ventilation systems, it is common to use plate heat exchangers. These can, for example, be of the cross-flow heat exchanger type and / or counter-current heat exchanger.
    The object of the present invention is to provide an improved salt to control defrosting of a heat exchanger.
    SUMMARY OF THE INVENTION The above objects are achieved by the invention defined by the independent claims.
    Preferred embodiments are defined by the dependent claims.
    According to a first aspect, the invention relates to a method for controlling defrosting of a heat exchanger. The heat exchanger comprises an exhaust air duct, a supply air duct, a flap for conducting exhaust air through the exhaust air duct and a heat exchange unit for transferring energy between these two ducts. The method includes determining the efficiency of the heat exchanger, to then consider the efficiency of the heat exchanger, and then making an assessment of whether the heat exchanger needs to be defrosted.
    By controlling the defrosting of a heat exchanger with respect to its efficiency, a more precise control is obtained of judging whether a defrosting should be carried out.
    The method of controlling the defrosting of a heat exchanger may include observing a parameter related to the rotation of the Mkt of the exhaust air. By controlling the defrosting of a heat exchanger dven with respect to the pH parameter related to the rotation of the exhaust air surface, an even more precise control is achieved of judging whether a defrosting should be re-effected.
    According to a second aspect, the invention relates to a system for a heat exchanger comprising an exhaust air duct, a supply air duct, a power for conducting exhaust air through the exhaust air duct and a heat exchanging unit for transferring energy between these two ducts. The system for the heat exchanger comprises food equipment in connection with the heat exchanger, the food equipment being adapted to collect data for the efficiency of the heat exchanger, which data is intended to be used in a storage unit for calculating the efficiency of the heat exchanger. The recovery unit is adapted to transmit an efficiency signal.
    The system also includes an evaluation unit adapted to receive the efficiency signal and to determine if the heat exchanger needs to be defrosted based on the pH.
    Brief Description of the Drawings Figure 1 schematically shows a system for a heat exchanger according to an embodiment of the present invention, Figure 2 schematically shows a system for a heat exchanger according to a second embodiment of the present invention, Figure 3 schematically shows a method for controlling defrosting of a heat exchanger according to an embodiment of the present invention. invention, Figure 4 schematically shows the construction of a heat exchanger, and Figure 4 is a flow chart showing the conditions in one embodiment of a method for controlling defrosting.
    Detailed Description of Preferred Embodiments of the Invention Figure 1 schematically shows a system for a heat exchanger according to an embodiment of the present invention. The heat exchanger 1 comprises an exhaust air duct 2, a supply air duct 3, a flat 4 for directing exhaust air through the exhaust air duct and a heat exchanging unit 5 for transferring energy between these two ducts. The system for the heat exchanger comprises feeding equipment 11 in connection with the heat exchanger 1, the measuring equipment 11 being adapted to collect data for the efficiency of the heat exchanger which data is intended to be used in a storage unit 12 for calculating the heat exchanger efficiency. . The system comprises an evaluation unit 14 adapted to receive the efficiency signal and to assess whether the heat exchanger needs to be defrosted based on the efficiency. The food equipment comprises sensors which are connected to the heat exchanger to supply temperature inside the supply air duct, T111 and outside mdta outdoor temperature, Tut ,. With the aid of these temperatures, the efficiency of the heat exchanger is generally calculated in the counting unit.
    Figure 2 schematically shows a system for a heat exchanger according to a second embodiment of the present invention. Several of the integral parts of the figure have been described in connection with Figure 1 above. In Figure 2, the feeding equipment 11 is further adapted to collect data for a parameter related to the rotation of the exhaust air N, which data is intended to be compiled in a recording unit 13, and wherein the recording unit 13 is adapted to transmit a rotation parameter signal SN. The system evaluation unit 14 is further adapted to receive the rotation parameter signal SN. Thus, the evaluation unit 14 can assess whether the heat exchanger needs to be defrosted both with respect to the efficiency and on the parameters related to the rotation of the flat N of the exhaust air.
    The measuring equipment then also comprises sensors which are connected to the exhaust air flow to supply the parameters related to the rotation of the exhaust air flow.
    Figure 3 schematically shows a method for controlling defrosting of a heat exchanger according to an embodiment of the present invention. The method includes determining the efficiency of the heat exchanger in order to take into account the efficiency of the heat exchanger and then assess whether the heat exchanger needs to be defrosted.
    The efficiency of the heat exchanger is compared to a predetermined value in, and then 1The method for controlling the defrosting of a heat exchanger may also comprise considering a parameter related to the rotation of the flat N of the exhaust air, the method may compare vdrmevd, the efficiency of the clare against the predetermined value 112 and compile the parameters related to the rotation of the exhaust air Mkt N during a time for aft berdkna the change of this parameter N 'Over time, N' = kxN. The value of k is thus measured by the change of the rotation parameter and where k2 is a predetermined value. Then the assessment is made that cla k> k2 and <12 should defrost the heat exchanger. The value of k2 is in the range between 0.0001 and 0.1, ddr after the subtracted value is 0.005. The value of 12 is in the range between 0.80 and 0.90, where a preferred value is 0.88. The value of 112 may also be otherwise within the range such as 0.82; 0.84 or 0.86.
    The method allows Liven to use the parameters related to the rotation of the exhaust air flow, N to determine if N> (a + bxNnorm). If this condition is met Ors' assessment that defrosting of the heat exchanger should take place. N0 is the standard value of the parameter related to the rotation of the exhaust air Mkt. The value of a is typically in the range between 0 and 0, and the value of b is probably in the range between 0.6 and 1.3. Preferably a = 0.3 and b = 0.85, but also other values in these ranges may be appropriate as for a 0.1; 0.2 or 0.4 and for b for example 0.7; 1.0; or 1.15.
    The method further comprises detecting whether the heat exchanger has been ice and frost free for at least a time t1 at an average outdoor temperature Tut. This is done in order to calibrate food equipment 11 in connection with the heat exchanger and to calibrate the standard value of the parameter related to the rotation of the exhaust air flow, Nnorm. The lamp is in the range between 12 and 48 hours and Tut is set to +4 ° C. The value that may be suitable for use on Tuesdays is, for example, 24 or 36 hours, or another value this interval. And for Tut, even after something higher or lower can be appropriate, for example +3; +3.5 or 4.5 ° C.
    The method also includes verification if defrosting has taken place within a time tAF. If defrosting has taken place Mom derma time Ors a new beclOmning if the heat exchanger needs defrosting time tAF after the last defrosting. The time for the last defrost, tAF was set at 12 hours. It is also possible that this time is shorter or longer as in the interval between 6 and 24 hours, for example 10, 14, 18 or 21 hours.
    Since the method has detected that a defrost is necessary, there are different ways in which the process for re-defrosting the heat exchanger proceeds as described above in the background of the invention.
    Figure 4 shows schematically how a heat exchanger 1 can be constructed. There is an exhaust air duct 2 for discharging exhaust air Lf out of the property in which the heat exchanger is installed and a supply air duct 3 RV to lead supply air Lt into the property. As mentioned above, temperatures are measured in connection with the heat exchanger to calculate the efficiency of the heat exchanger. Sensors are located next to the heat exchanger to on the inside, called INSIDE the figure, feed temperature in the supply air duct, T1u and temperature in the exhaust air duct, Tfrau and on the outside (OUT) to feed the outside temperature, Tutu. The efficiency of the heat exchanger, ri is calculated as follows: TtiTute = T from Tute The efficiency of the heat exchanger, 1 can be an average efficiency calculated as an average of the efficiency over a certain number of hours, for example 1, 2, 4, 8 or 12 hours. However, continuous registration takes place of the parameters that the food equipment 11 feeds.
    In addition, it is appropriate for a sensor to be adjacent to the exhaust air gap 4 before feeding a parameter related to the rotation of the exhaust air gap. The parameter related to the rotation of the Mkt of the exhaust air can be, for example, feeding the rotational frequency of the flux (usually in the unit vary per minute) or a control signal to the flux which determines its rotation (for example a voltage signal). The exhaust air flap 4 is located in the exhaust air duct on the inside of the heat exchanger. The heat exchanger also includes a Mkt 6 for guiding supply air, this is located on the outside of the heat exchanger in the supply air duct. Furthermore, the heat exchanger comprises a heat exchanging unit 5 for transferring energy between the exhaust air and supply air duct.
    Figure 5 is a flow chart illustrating the conditions in an embodiment of a method for controlling defrosting of a heat exchanger according to the present invention. As described above in connection with Figures 1 and 2, the calculating unit 12 is adapted to transmit an efficiency signal Sri and the recording unit 13 is adapted to transmit a rotation parameter signal SN. These signals contain information about the current efficiency 1 and the current value of the parameter related to the rotation of the Mkt N of the exhaust air, which are evaluated in the river diagram as follows.
    Initially, a verification of defrosting took place within a time tAF. If defrosting has occurred within this time Ors a new assessment if the heat exchanger needs to be defrosted the time tAF after the last defrosting. During colder periods, it may be appropriate for defrosting to take place at most twice a day, ie. at about 12 hour intervals, as described above.
    Thereafter, an assessment of defrosting shall be made by considering the efficiency of the heat exchanger TI, where the efficiency is compared to a predetermined value. value 111, at least one additional condition must be assessed to determine whether a defrost should occur.
    In the next step, it is decided whether a defrost should be carried out by taking into account both the heat exchanger's efficiency r and the parameters related to the rotation of the exhaust air flake N. Then the condition that the current efficiency 1 is lower than the predetermined value TI2 and the current value of the parameter related to the change. of the rotation k of the exhaust air surface is higher than a predetermined value k2, a defrost must be performed. If any of these two conditions are not met, the defrost will not be deemed necessary, but then an additional condition will be assessed to decide whether a defrost should take place.
    Finally, in a final step, the assessment of the defrosting will only be made on the basis of the parameter related to the rotation of the exhaust air flake N. DA the current parameter related to the rotation of the exhaust air flake N is greater than a + bxNnorm, Ors beaming that defrosting of the heat exchanger should take place. N0 is a predetermined norm value of the parameters related to the rotation of the exhaust air flow and a and b are predetermined factors.
    In order for Ora to make an assessment of defrosting, it can therefore only be possible to determine when defrosting needs to take place with the help of the heat exchanger's efficiency. Alternatively, this is combined with also considering the parameters related to the rotation of the exhaust air flow.
    The present invention is not limited to the preferred embodiments described above. Various alternatives, modifications and equivalents can be used. The above-mentioned embodiments should not be construed as limiting the scope of the invention, as defined by the appended claims.
    权利要求:
    Claims (16)
    [1]
    A method for controlling defrosting of a heat exchanger (1), wherein the heat exchanger comprises an exhaust air duct (2), a supply air duct (3), a flap (4) for directing exhaust air through the exhaust air duct and a heat exchanging unit (5) for transmitting energy between these two channels, the method comprising determining the efficiency of the heat exchanger 1, taking into account the efficiency of the heat exchanger i, and - assessing whether the heat exchanger needs to be defrosted.
    [2]
    The method of claim 1, wherein the method further comprises considering a parameter related to the rotation of the air flow N.
    [3]
    A method according to claim 1, wherein the efficiency of the heat exchanger is compared to a predetermined value 111, and then 11
    [4]
    The method of claim 3, wherein i is in the range between 0.60 and 0.90.
    [5]
    The method of claim 3, wherein ii = 0.84.
    [6]
    A method according to claim 2, wherein the efficiency of the heat exchanger in comparison with a predetermined value ri2 and the parameters related to the rotation of the exhaust air N are compiled for a certain time to calculate the change of this parameter N 'Over time, N' = kxN, where da k> k2 and i <112 Ors assessment that defrosting of the heat exchanger should take place.
    [7]
    The method of claim 6, wherein k 2 is in the range between 0.0001 and 0.1, and 12 is in the range between 0.80 and 0.90.
    [8]
    The method of claim 6, wherein k 2 = 0.005 and 112 = 0.88.
    [9]
    Method according to claim 2, wherein the parameter related to the rotation of the exhaust air flake, N> (a + bxNuomi) Ors assessment of defrosting of the heat exchanger shall take place, and where Nuorm is a standard value of the parameter related to the rotation of the exhaust air flake and where a is in the range between 0 and 0.5 and b is in the range between 0.6 and 1.3.
    [10]
    The method of claim 9, wherein a = 0.3 and b = 0.85.
    [11]
    Method according to any one of the preceding claims, comprising det detecting that the heat exchanger has been ice and frost free for at least a time t at an average outdoor temperature Tut, for calibrating food equipment (11) in connection with the heat exchanger and for calibrating the standard value of the parameter related to the rotation of the exhaust air flake Nnorm.
    [12]
    The method of claim 11, wherein tis is in the range between 12 and 48 hours and Tut = +4 ° C.
    [13]
    Method according to one of the preceding claims, comprising verification of defrosting shaft thorn a time tAF, defrosting has taken place within this time Ors a new assessment if the heat exchanger needs to be defrosted time tAF after the last defrosting.
    [14]
    The method of claim 13, wherein the time of last defrost, tAF is in the range between 6 and 24 hours.
    [15]
    A system comprises a heat exchanger (1) comprising an exhaust air duct (2), a supply air duct (3), a flap for conducting exhaust air through the exhaust air duct (4), and a heat exchanging unit for transferring energy between these two ducts (5), the system comprising food equipment (11) in connection with the heat exchanger (1), the food equipment (11) being adapted to collect data for the efficiency of the heat exchanger, which data is intended to be used in a calculation unit (12) for calculating the efficiency (s) of the heat exchanger, and wherein the calculating unit (12) is adapted to transmit an efficiency signal ST1, 11 characterized in that the system comprises an evaluation unit (14) adapted to receive the efficiency signal S and to assess whether the heat exchanger needs to be defrosted based on the pH r.
    [16]
    A heat exchanger system (1) according to claim 15, wherein the food equipment (11) is further adapted to collect data for a parameter related to the rotation of the exhaust air flake N, which data is intended to be co-installed in a recording unit (13), and wherein the recording unit (13) is adapted to transmit a rotation parameter signal SN, characterized by the system comprising an evaluation unit (14) further adapted to receive the rotation parameter signal SN and to assess whether the heat exchanger needs to be defrosted based on the parameter related to the rotation of exhaust air N. N 11 SN 12 evaluation '- 14 Heat exchangers / 12 evaluation 13 14 11
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    同族专利:
    公开号 | 公开日
    WO2013048327A1|2013-04-04|
    SE537165C2|2015-02-24|
    引用文献:
    公开号 | 申请日 | 公开日 | 申请人 | 专利标题
    FI76210C|1986-02-03|1988-09-09|Ilmateollisuus Oy|Method for controlling a heat exchanger in a ventilation system|
    US20060151165A1|2002-08-16|2006-07-13|Bertrand Poirier|Proportional control system for a motor|
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    CA2596151A1|2007-08-03|2009-02-03|Air Tech Equipment Ltd.|Method and apparatus for controlling ventilation system|SE540735C2|2017-03-31|2018-10-23|Flaektgroup Sweden Ab|Method for counteracting the build-up of frost on a heat recycler arranged at an air treatment unit|
    法律状态:
    优先权:
    申请号 | 申请日 | 专利标题
    SE1150905A|SE537165C2|2011-09-30|2011-09-30|Method and system for controlling the defrosting of a heat exchanger|SE1150905A| SE537165C2|2011-09-30|2011-09-30|Method and system for controlling the defrosting of a heat exchanger|
    PCT/SE2012/051034| WO2013048327A1|2011-09-30|2012-09-27|Method and system for controlling defrosting of a heat-exchanger|
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