Systems, methods, and controller for adaptive fouling detection for heat exchangers

Abstract

A controller is configured to implement a process including automated valve control, sensor feedback integration, and real-time performance monitoring. By recalibrating pressure drop baselines post-cleaning while preserving initial startup values, the process ensures accurate fouling detection and efficient heat exchanger operation. The process includes calculating a similarity parameter that normalizes the pressure drop over flow rate, viscosity and density. In other words, if two operating conditions have the same similarity parameter, they will create the same pressure drop across the heat exchanger — even if their actual flow rate, viscosity and density values differ. The process reduces the need for manual recalibration after cleaning cycles, improving system reliability and reducing maintenance costs. In examples, the process is applicable to simplex and multiplex configurations (i.e. one heat exchanger or multiple heat exchangers in parallel) and enhances operational efficiency by continuously adapting to changing system conditions.

Description

SYSTEMS, METHODS, AND CONTROLLER FOR ADAPTIVE FOULING DETECTION FOR HEAT EXCHANGERS CROSS-REFERENCE

[0001] This application claims the benefit of priority to U.S. Provisional Patent Application No. 63 / 755,791 filed February 7, 2025 entitled SYSTEMS, METHODS, AND CONTROLLER FOR ADAPTIVE FOULING DETECTION FOR HEAT EXCHANGERS, the entire contents of which are herein incorporated by reference into the Detailed Description herein below.TECHNICAL FIELD

[0002] Example embodiments generally relate to heat transfer systems and heat exchangers.BACKGROUND

[0003] Heating Ventilation and Air Conditioning (HVAC) systems for a premises such as a building can contain central chilled water plants that are designed to provide air conditioning units with cold water as to reduce the temperature of the air that leaves the conditioned space before it is recycled back into the conditioned space during summer conditions. Similarly applicable for heating application where hot water from the boiler is used for heating the air in the building during winter conditions.

[0004] Chilled water plants are used to provide cold water or air for a building. Chilled water plants can comprise of active and passive mechanical equipment which work in concert to reduce the temperature of warm return water before supplying it to the distribution circuit. In chilled water plants, a heat exchanger is used to transfer heat energy between two or more circuits of circulation mediums. Similarly, a heating plant can include heat sources such as one or more boilers that provide hot water or air to the distribution circuit, from one or more boilers or from a secondary circuit having the heating source.

[0005] It can be challenging to detect fouling and performance of a heat exchanger, for example during after startup, or after maintenance, or during real-time operation. It can be challenging to determine when automated or manual maintenance is required.

[0006] Other difficulties with existing systems may be appreciated in view of the Detailed Description of Example Embodiments, herein below.SUMMARY

[0007] An example embodiment is a controller that is configured to perform adaptive fouling detection for heat exchangers.

[0008] An example embodiment is a process implemented by a controller includes automated valve control, sensor feedback integration, and real-time performance monitoring. By recalibrating pressure drop baselines post-cleaning while preserving initial startup values, the process ensures accurate fouling detection and efficient heat exchanger operation. The process includes calculating a similarity parameter that normalizes the pressure drop overflow rate, viscosity and density. In other words, if two operating conditions have the same similarity parameter, they will create the same pressure drop across the heat exchanger — even if their actual flow rate, viscosity and density values differ. The process reduces the need for manual recalibration after cleaning cycles, improving system reliability and reducing maintenance costs. In examples, the process is applicable to simplex and multiplex heat exchanger configurations (i.e. one heat exchanger or multiple heat exchangers in parallel) and enhances operational efficiency by continuously adapting to changing system conditions.

[0009] An example embodiment is a method for a heat transfer module for connection to a first fluid circuit and a second fluid circuit and configured for flow of at least one fluid, wherein the heat transfer module includes at least one heat exchanger, the method being performed by at least one controller and comprising: receiving data indicative of measurement of flow, temperature, and pressure drop of the at least one fluid; calculating, for each heat exchanger based on the data, a similarity parameter that normalizes the pressure drop across that heat exchanger over flowrate, fluid viscosity and fluid density; and generating, for each heat exchanger, a function of the pressure drop versus the similarity parameter.

[0010] In another example embodiment of any of the above, the calculating comprises calculating:similarity parameter = density0 75x flow1 75x viscosity0 25(Equation 1);wherein:density = the fluid density of one fluid of the at least one fluid,viscosity = the fluid viscosity of the one fluid, andflow = the flow of the one fluid through the heat transfer module.

[0011] In another example embodiment of any of the above, the fluid density of the one fluid and the fluid viscosity of the one fluid are dependent on the temperature.

[0012] In another example embodiment of any of the above, the data is measured during real-time operation of the heat transfer module or during real-time operation by the heat transfer module to satisfy a load.

[0013] In another example embodiment of any of the above, the data is measured at different flow values.

[0014] In another example embodiment of any of the above, the flow values include 50% of maximum design flow.

[0015] In another example embodiment of any of the above, the flow values include 50% to 100% of maximum design flow at 10% increments.

[0016] In another example embodiment of any of the above, the similarity parameter defines the pressure drop so as to be comparable for all operating ranges of the flow rate, the fluid viscosity and the fluid density of the fluid.

[0017] In another example embodiment of any of the above, the at least one heat exchanger comprises a plurality of heat exchangers in parallel, wherein the calculating and the generating is performed individually for each heat exchanger that has been activated one at a time.

[0018] In another example embodiment of any of the above, the calculating includes calculating a plurality of the similarity parameter at respective different pressure drop.

[0019] In another example embodiment of any of the above, the generating the function includes inferring from the plurality of similarity parameter at the respective different pressure drop.

[0020] In another example embodiment of any of the above, the calculating of the similarity parameter is performed individually for a first fluid of the at least one fluid in the first fluid circuit and a second fluid of the at least one fluid in the second fluid circuit.

[0021] In another example embodiment of any of the above, the method further includes determining, based on the comparison of previous pressure drops and current pressure drops for the similarity parameter, that the heat transfer module is fouled.

[0022] In another example embodiment of any of the above, the function includes an ordered set, a model, a straight-line function, and / or a polynomial function.

[0023] In another example embodiment of any of the above, the calculating and the generating is for an initial state of the at least one heat exchanger prior to operation in a heat transfer system or at or prior to installation in the heat transfer system, and wherein the function includes an initial function for the initial state.

[0024] In another example embodiment of any of the above, the heat transfer system includes a chilled water process, space cooling system, a hot water process, and / or space heating system.

[0025] In another example embodiment of any of the above, the calculating and the generating is for a clean state of the at least one heat exchanger after cleaning or flushing of the at least one heat exchanger, further comprising recording a set of data including a post-clean similarity parameter at a post-clean pressure drop for the clean state, and wherein the function includes a post-clean function for the clean state.

[0026] In another example embodiment of any of the above, the generating the clean function includes mathematically scaling the initial function to the post-clean pressure drop at the post-clean similarity parameter.

[0027] In another example embodiment of any of the above, the generating the clean function includes mathematically scaling a previous clean function to the post-clean pressure drop at the post-clean similarity parameter.

[0028] In another example embodiment of any of the above, the method further includes determining that a percentage difference of the post-clean function to the initial function exceeds a threshold, and in response to the determining, generating an alert of a fouling of the heat transfer module.

[0029] In another example embodiment of any of the above, the threshold is user adjustable.

[0030] In another example embodiment of any of the above, the initial function is inferred.

[0031] In another example embodiment of any of the above, the calculating is for a clean state of the at least one heat exchanger after cleaning or flushing of the at least one heat exchanger, wherein the similarity parameter includes a post-clean similarity parameter at a post-clean pressure drop for the clean state, further comprising determining that a percentage difference of the post-clean pressure drop at the postclean similarity parameter to the initial pressure drop at the post-clean similarity parameter exceeds a threshold.

[0032] In another example embodiment of any of the above, the determining of the percentage difference of the post-clean pressure drop at the post-clean similarity parameter to the initial pressure drop at the post-clean similarity parameter is determined for maximum design flow, and in response to the determining, generating an alert of a fouling of the heat transfer module.

[0033] In another example embodiment of any of the above, the threshold is user-adjustable.

[0034] In another example embodiment of any of the above, the at least one controller is attached to or part of the heat transfer module.

[0035] In another example embodiment of any of the above, the at least one controller is separate from the heat transfer module.

[0036] Another example embodiment is a method for an apparatus configured to have flow of at least one fluid, the method being performed by at least one controller and comprising: calculating, for the apparatus, a similarity parameter of a fluid of the at least one fluid that normalizes the pressure drop across the apparatus over flow rate, fluid viscosity and fluid density; and generating, for the apparatus, a function of the pressure drop versus the similarity parameter.

[0037] In another example embodiment of any of the above, the similarity parameter defines the pressure drop so as to be comparable for all operating ranges of the flow rate, the fluid viscosity and the fluid density of the fluid.

[0038] In another example embodiment of any of the above, the calculating includes calculating a plurality of the similarity parameter at respective different pressure drop.

[0039] In another example embodiment of any of the above, the calculating comprises calculating:similarity parameter = density075x flow1-75x viscosity025(Equation 1);wherein:density = the fluid density of one fluid of the at least one fluid,viscosity = the fluid viscosity of the one fluid, andflow = the flow of the one fluid through the apparatus.

[0040] In another example embodiment of any of the above, the fluid density of the one fluid and the viscosity of the one fluid are dependent on temperature.

[0041] In another example embodiment of any of the above, the method further includes receiving data indicative of measurement of flow, temperature, and the pressure drop of the apparatus, wherein the calculating uses the data.

[0042] In another example embodiment of any of the above, the data is measured during real-time operation of the apparatus or during real-time operation by the apparatus to satisfy a load.

[0043] In another example embodiment of any of the above, the apparatus is a heat transfer module including at least one heat exchanger and configured for connection to a first fluid circuit and a second fluid circuit, wherein the calculating of the similarity parameter is performed individually for a first fluid of the at least one fluid in the first fluid circuit and a second fluid of the at least one fluid in the second fluid circuit.

[0044] In another example embodiment of any of the above, the at least one heat exchanger comprises a plurality of heat exchangers in parallel, wherein the calculating and the generating is performed individually for each heat exchanger that has been activated one at a time.

[0045] In another example embodiment of any of the above, the method further includes determining, based on comparison of previous pressure drops and current pressure drops for the similarity parameter, that the apparatus is fouled.

[0046] Another example embodiment is a method performed by at least one controller configured to perform any one of the above.

[0047] Another example embodiment is a non-transitory computer readable medium having instructions stored thereon executable by at least one controller for performing the method of any one of the above.

[0048] Another example embodiment is a heat transfer system, comprising: a heat transfer module, comprising: a sealed casing that defines a first port and a second port configured for connection to a first fluid circuit across the first port and the second port, and that defines a third port and a fourth port configured for connection to a second fluid circuit across the third port and the fourth port, and at least one heat exchanger within the sealed casing configured for connection to the first fluid circuit port and the second fluid circuit; a first differential pressure sensor configured to detect first pressure drop across the first fluid circuit of the heat transfer module; a second differential pressure sensor configured to detect second pressure drop across the second fluid circuit of the heat transfer module; a first temperature sensor configured to detect first temperature measurement of first input of the first fluid circuit of the heat transfer module; a second temperature sensor configured to detect second temperature measurement of first output of the first fluid circuit of the heat transfer module; a third temperature sensor configured to detect third temperature measurement of second input of the second fluid circuit of the heat transfer module; a fourth temperature sensor configured to detect fourth temperature measurement of second output of the second fluid circuit of the heat transfer module; a first flow metering device configured to detect first flow measurement of the first fluid circuit; a second flow metering device configured to detect second flow measurement of the second fluid circuit; and at least one controller configured to: receive data from the first differential pressure sensor, the second differential pressure sensor, the first temperature sensor, the second temperature sensor, the third temperature sensor, the fourth temperature sensor, the first flow metering device, and the second flow metering device, and perform the method of any of the above.BRIEF DESCRIPTION OF THE DRAWINGS

[0049] Reference will now be made, by way of example, to the accompanying drawings which show example embodiments, and in which:

[0050] Figure 1 A illustrates a graphical representation of a building system, illustrated as a chilled water plant for providing cold water to a building, to which example embodiments may be applied.

[0051] Figure 1 B illustrates a graphical representation of further aspects of the chilled water plant shown in Figure 1A.

[0052] Figure 2A illustrates a graphical representation of a heat exchanger, in accordance with an example embodiment.

[0053] Figure 2B illustrates a perspective view of an example heat transfer module with two heat exchangers, in accordance with an example embodiment.

[0054] Figure 3A illustrates a graphical representation of network connectivity of a heat transfer system, having local setup.

[0055] Figure 3B illustrates a graphical representation of network connectivity of a heat transfer system, having remote setup.

[0056] Figure 4A shows an example graph which illustrates an example method for determining that a heat exchanger is fouled.

[0057] Figure 4B shows an example of a method performed for initializing the method illustrated in Figure 4A.

[0058] Figure 40 shows an example of a method performed after each cleaning for the method illustrated in Figure 4A.

[0059] Similar reference numerals may have been used in different figures to denote similar components.DETAILED DESCRIPTION

[0060] Example embodiments generally relate to adaptive fouling detection for heat exchangers.

[0061] At least some example embodiments relate to processes, process equipment and systems in the industrial sense, meaning a process that outputs product(s) (e.g. hot water, cool water, air) using inputs (e.g. cold water, fuel, air, etc.). In such systems, a heat exchanger or heat transfer system can be used to transfer heat energy between two or more circuits (fluid paths) of circulation mediums. In some systems, an air separator can be used to remove air (and sometimes dirt) from the circulation medium.

[0062] At least some example embodiments relate to equipment in a system such as an HVAC system, temperature control system, heat transfer system, hydronic system, or flow control system.

[0063] Figure 1A illustrates an example building system 100 such as a chilled water plant, in accordance with an example embodiment. In an example, the building system 100 is a HVAC building system. As shown in Figure 1A, the building system 100 can include, for example: one control pump 102a for load, one chiller 120, one control pump 102b for source, an air separator 132, and two cooling towers 124. The chilled water control pump 102 can include a heat exchanger 118. The heat exchanger 118 can include sensors 150. The heat exchanger 118 defines a first fluid path 204 (of a first fluid circuit) for a first circulation medium, and a second fluid path 206 (of a second fluid circuit) for a second circulation medium. In an example embodiment, more or fewer numbers of device can exist within each equipment category. Other types of equipment, rotary devices, and flow control devices (e.g. valves) may be included in the building system 100.

[0064] The building system 100 can be used to source a building 104 (as shown), campus (multiple buildings), premises, district, vehicle, plant, generator, heat exchanger, or other suitable infrastructure or load, with suitable adaptations. The control pump 102a may include one or more respective pump devices 106a (one shown here) and a controldevice 108a for controlling operation of the pump device 106a. The control pump 102b can have a variably controllable motor, and can include a pump device 106b and a control device 108b. The particular circulation medium may vary depending on the particular application, and may for example include glycol, water, air, fuel, and the like. The chiller 120 can include at least a condenser and an evaporator, for example, as understood in the art. The condenser of the chiller 120 collects unwanted heat through the circulation medium before the circulation medium is sent to the cooling towers 124. The chiller 120 itself is (or is part of) a heat exchanger, and examples embodiments that refer to a heat exchanger can be applied to the chiller 120, as applicable. The evaporator of the chiller 120 is where the chilled circulation medium is generated, and the chilled circulation medium leaves the evaporator and is flowed to the building 104 by the control pump 102a. Each cooling tower 124 can be dimensioned and configured to provide cooling by way of evaporation, and can include a respective fan, for example. Each cooling tower 124 can include one or more cooling tower cells, in an example.

[0065] The building system 100 can be configured to provide air conditioning units of the building 104 with cold water to reduce the temperature of the air that leaves the conditioned space before the air is recycled back into the conditioned space. The building system 100 can comprise of active and passive mechanical equipment which work in concert to reduce the temperature of warm return water before supplying it to the distribution circuit.

[0066] Referring to Figure 1 B, the building system 100 may include a heat exchanger 118 which is an interface in thermal communication with a secondary circulation system, for example via the chiller 120 (Figure 1A), ambient, or a temperature source. The heat exchanger 118 can be placed in various positions in the building system 100 of Figure 1B. The air separator 132 can be placed in various positions in the building system 100 of Figure 1B, and is typically positioned upstream of the control pump 102a. The building system 100 may include one or more loads 110a, 110b, 110c, 110d, wherein each load 110a, 110b, 110c, 110d may be a varying usage requirement based on requirements of an air conditioner, HVAC, plumbing, etc. Each 2-way valve 112a, 112b, 112c, 112d may be used to manage the flow rate to each respective load 110a, 110b, 110c, 110d. In some example embodiments, as the differential pressure across theload decreases, the control device 108a responds to this change by increasing the pump speed of the pump device 106a to maintain or achieve the output setpoint (e.g. pressure or temperature). If the differential pressure across the load increases, the control device 108a responds to this change by decreasing the pump speed of the pump device 106a to maintain or achieve the setpoint. In some example embodiments, an applicable load 110a, 110b, 110c, 110d can represent cooling coils to be sourced by the circulation medium the chiller 120, each with associated valves 112f, 112b, 112c, 112d, for example. In some examples, an applicable load 110a, 110b, 110c, 110d can represent fan coils that each include a cooling coil and a controllable fan (not shown) that blows air across the coiling coils. In some examples, the fan has a variably controllable motor to control temperature in the region to be cooled. In other examples, the fan has a binary controllable motor (e.g., only on state or off state) to control temperature in the region to be cooled. The control devices 108a and the control valves 112a, 112b, 112c, 112d can respond to changes in the chiller 120 by increasing or decreasing the pump speed of the pump device 106a, or variably controlling an amount of opening or closing of the control valves 112a, 112b, 112c, 112d, or control of the fans, to achieve the specified output setpoint.

[0067] In Figure 1A, the control pump 102b (more than one control pump is possible) is used to provide flow control from the cooling towers 124 to the chiller 120 (which can include the heat exchanger 118). In various examples, the control pump 102b can be used to control flow from a cooling or heating source to the heat exchanger 118. In some examples, the heat exchanger 118 is separate from the chiller 120. In other examples, the chiller 120 is integrated with the heat exchanger 118. In some examples, the heat exchanger 118 is integrated with one or both control pumps 102a, 102b. In other examples, the heat exchanger 118 is separated from the control pumps 102a, 102b using piping, fittings, intermediate devices, etc. The control pumps 102a, 102b can be referred to as variable control pumps. The control pumps 102a, 102b are variable flow control mechanical devices. Other types variable flow control mechanical devices can be used in other example embodiments, such as variable control valves or pressure independent control valves (PICVs). In an example, not shown here, the secondary circulation system sourced by the control pump 102b can also include a respective air separator 132.

[0068] Referring to Figure 1 B, the output properties of each control pump 102a, 102b can be controlled to, for example, achieve a temperature setpoint or pressure setpoint at the combined output properties represented or detected by external sensor 114, shown at the load 110d at one point of the building 104 (e.g., the highest point in this example). The external sensor 114 represents or detects the aggregate or total of the individual output properties of all of the control pumps 102a, 102b at the load, in one example, flow and pressure. Information on flow and pressure local to the control pump 102a, 102b can also be represented or detected by a respective sensor 130, in an example embodiment. The external sensor 114 can be used to detect temperature and heat load (Q) in example embodiments. Heat load (Q) can refer to a hot temperature load or a cold temperature load. In an example, the external sensor 114 for temperature and heat load can be placed at each load (110a, 110b, 110c, 11 Od), or one external sensor 114 is placed at the highest point at the load 110d. Other example operating parameters are described in greater detail herein.

[0069] One or more controllers 116 (can be generally denoted controller 116 or controllers 116), which can include one or more processors, may be used to coordinate the output (e.g. temperature, pressure, and flow) of some or all of the devices of the building system 100. The controllers 116 can include a main centralized controller in some example embodiments, and / or can have some of the functions distributed to one or more of the devices in the overall system of the building system 100 in some example embodiments. In an example embodiment, the controllers 116 are implemented by a processor which executes instructions stored in memory. In an example embodiment, the controllers 116 are configured to control or be in communication with the loads (110a, 110b, 110c, 110d), the valves (112a, 112b, 112c, 112d), the control pumps 102a, 102b, the heat exchanger 118, and other equipment and devices.

[0070] Referring again to Figures 1 A and 1 B, in some example embodiments, the building system 100 can represent a heating circulation system (“heating plant”), with suitable adaptation. The heating plant may include a heat exchanger 118 which is an interface in thermal communication with a secondary circulation system, such as a boiler system. Instead of a chiller 120, the boiler system can include one or more boilers 140 (not shown here). In an example, control valves 112a, 112b, 112c, 112d manage the flowrate to heating elements (e.g., loads 110a, 110b, 110c, 110d). The control devices 108a, 108b and the control valves 112a, 112b, 112c, 112d can respond to changes in the heating elements (e.g., loads 110a, 110b, 110c, 110d) and the boiler system by increasing or decreasing the pump speed of the pump device 106a, or variably controlling an amount of opening or closing of the control valves 112a, 112b, 112c, 112d, to achieve the specified output setpoint (e.g., temperature or pressure). In some examples, the one or more boilers 140 is separate from the heat exchanger 118. In other examples, the one or more boilers 140 is integrated with the heat exchanger 118. In other examples, other heat sources or cooling sources can be used to source the secondary circulation system.

[0071] Each control device 108a, 108b can be contained in a Pump Controller card 226 (“PC card”) that is integrated within the respective control pump 102a, 102b. A controller (with communication device) of the heat exchanger 118 can be contained in a Heat exchanger card 222 (“HX card”) that is integrated within the heat exchanger 118. In an example, the PC card 226 can be a tablet style device that includes a touch screen, processor, and communication subsystem, that can be stand alone manufactured and then integrated into the respective control pump 102a, 102b. The HX card 222 is integrated with heat exchanger 118, and can be a similar tablet style device as the PC card 226 having a touch screen 228 in some examples, and in some examples does not have the touch screen 228. In an example, the PC card 226 can be the control device 108a, 108b of the control pump 102a, 102b (Figure 1 A).

[0072] Figure 2A illustrates a graphical representation of the heat exchanger 118, in accordance with an example embodiment. The heat exchanger 118 is a plate type counter current heat exchanger in an example. The heat exchanger 118 includes a frame 200 that is a sealed casing. The heat exchanger 118 defines a first fluid path 204 (of a first fluid circuit) for a first circulation medium, and a second fluid path 206 (of a second fluid circuit) for a second circulation medium. The first fluid path 204 is not in fluid communication with the second fluid path 206. The first fluid path 204 is in thermal contact with the second fluid path 206. The first fluid path 204 can flow in an opposing flow direction (counter current) to the second fluid path 206. In an example, the heat exchanger 118 is a brazed plate heat exchanger (BPHE). A plurality of brazed plates 202 are parallel plates that facilitate heat transfer between the first fluid path 204 and thesecond fluid path 206. The first fluid path 204 and the second fluid path 206 flow between the brazed plates 202, typically the first fluid path 204 and the second fluid path 206 are in alternating fluid paths of the brazed plates 202. The plurality of brazed plates 202 are dimensioned with braze patterns for causing turbulence to promote heat transfer between the first fluid path 204 and the second fluid path 206. Turbulent flow in the heat exchanger 118 is increased (decreases probability of turbulent flow), and as a result there is a higher pressure drop across the heat exchanger 118. Turbulent flow promotes loosing of fouling on the braze patterns of the brazed plates 202. For a smaller heat exchanger 118 (which uses less material), a higher pressure drop increases turbulent flow (decreases probability of turbulent flow) but also requires higher pump energy consumption. In other examples, the heat exchanger 118 is a shell and tube (S&T) type heat exchanger, or a gasketed plate heat exchanger (PHE)).

[0073] The load side is the side that is connected to the load requiring heat such as a building or room. Variable flow through the load side is controlled by the control pump 102a. The source side is connected to the source of heat that is to be transferred such as the chiller 120, boiler 140, or district source. Variable flow through the source side is controlled by the control pump 102b. There are two conventions that can be used to notate parameters in heat transfer loops. The first convention, parameters such as temperature and flow are taken with reference to the heat exchanger 118. That is, for example, the water temperature going in to the heat exchanger 118 from the source side is called Tsource, in. The water temperature going out of the heat exchanger 118 from the source side is called Tsource, out.

[0074] An alternate convention is that parameters are notated such that, on the source side, the supply is taken as the fluid provided from the source to the heat exchanger 118 and the return is taken as the fluid returned to the source. For the load side, the supply is taken as the fluid provided to the load and the return is the fluid returned from the load. This is taken from chiller and fan coil conventions. For the purpose of calculations, examples herein will mainly refer to the first convention referencing the in and out looking from the heat exchanger 118.

[0075] In example embodiments, any or all of control pumps 102a, 102b can be replaced with, or used in combination with, other types of variable flow controlmechanical devices such as variable control valves or pressure independent control valves (PICVs). For example, in example embodiments, rather than the load side control pump 102b, another type of flow control mechanical device such as a variable control valve is used instead of the control pump 102b. The source side can be connected to the source of heat that is to be transferred such as the chiller 120, boiler 140, or district source, which may have their own pumps (not necessarily controllable by the controllers 116) and provide a constant or variable flow to the heat exchanger 118. The variable flow on the source side of the heat exchanger 118 is controlled by the variable control valve. Information detected by one or more of the described sensors can be used to determine the variable control of the variable control valve (e.g., the amount of opening), to achieve the desired amount of flow. For example, municipal flow has a variable source pressure to the heat exchanger 118, and the variable control valve can be used to control the flow to the heat exchanger.

[0076] In an example, not shown, the variable control valve includes a controller and a variable valve that is controlled by the controller. The controller of the variable control valve can be configured for communication with the controllers 116, for example to receive instructions on the variable amount of opening or flow, and for example to send the current status of the variable amount of opening or flow. The variable control valve can include a variably controllable ball valve in some examples. Other example variable control valves include cup valves, gear valves, screw valves, etc. The variable control valve can include onboard sensors, and may perform self-adjustment, monitoring and control using its controller. The variable control valve can be pressure independent in some examples. The variable control valve can be a 2-way variable control valve in some examples.

[0077] The frame 200 of the heat exchanger 118 can include four ports 208, 210, 212, 214, as shown in Figure 2A. Port 208 is for Source, In or Source, Supply. Port 210 is for Source, Out or Source, Return. Port 212 is for Load, Out or Load, Supply. Port 214 is for Load, In or Load, Return. In an example, the frame 200 is an integrated sealed casing that cannot be disassembled, because maintenance is performed by way of flushing through the ports 208, 210, 212, 214.

[0078] Various sensors can be used to detect and transmit measurement of the heat exchanger 118. The sensors can include sensors that are integrated with the heat exchanger 118, including sensors for: Temperature Source, In (TSource, In) sensor 150a; Temperature Source, Out (TSource, In) sensor 150b; Temperature Load, Out (TLoad, Out) sensor 150c; Temperature Load, In (TLoad, In) sensor 150d; Differential Pressure between Source, In and Source, Out sensor 150e; Differential Pressure between Load, In and Load, Out sensor 150f ; Pressure at Source, In sensor 150g;Pressure at Load, In sensor 150h. More orfewerof the sensors can be used in various examples, depending on the particular parameter or coefficient being detected or calculated, as applicable. In some examples, the sensors include flow sensors (also called flow metering devices) for: Flow, source (Fsource) sensor 150i; and Flow, load (Fload) sensor 150j, which are typically external to the heat exchanger 118, and can be located at, e.g., the control pump 102, 122, or the external sensor 114, or the load 110a, 110b, 110c, 110d.

[0079] Baseline measurement from the sensors is stored to memory for comparison with subsequent real-time operation measurement from the sensors. The baseline measurement can be obtained by factory testing using a testing rig, for example. In some examples, the baseline measurement can be obtained during real-time system operation.

[0080] Example embodiments include a heat transfer module that can include one or more heat exchangers 118 within a single sealed casing (frame 200), wherein Figure 2B illustrates a heat transfer module 220 with two heat exchangers 118 and Figures 2C and 2D illustrate a heat transfer module 230 with three heat exchangers 118.

[0081] Figure 2E illustrates a heat transfer system 240 that includes the heat transfer module 230 and control pumps 102a, 102b. In examples, the heat transfer module can include one, two, three or more heat exchangers 118 within the single sealed casing (frame 200). The heat transfer system 240 provides a reliable and optimized heat transfer solution comprised of heat exchanger(s) 118 and control pumps 102a, 102b by providing an optimized heat transfer system solution rather than providing equipment sized for duty conditions only. The heat transfer system 240 can be used for liquid to liquid HVAC applications with typical applications in residential, commercial, industrialand public buildings, district heating or cooling, etc. Applications include cooling, heating, water side economizer (e.g., cooling tower), condenser isolation (e.g., lake, river, or ground water), district heating and cooling, pressure break, boiler heating, thermal storage, etc. The heat transfer system 240 can be shipped as a complete package or optionally shipped in modules that can be quickly assembled on site.

[0082] Figure 2B illustrates a perspective view of the heat transfer module 220 with two heat exchangers 118a, 118b, in accordance with an example embodiment. The heat transfer module 220 includes the HX card 222 for receiving measurement from the various sensors of the heat transfer module 220, determining that maintenance is required on the heat transfer module 220, and communicating that maintenance is required to the controllers 116 or the control pumps 102a, 102b. Shown are ports 208, 210, 214, note that port 212 is not visible in this view in Figure 2B. A touch screen 228 can be used as a user interface for user interaction with the respective heat transfer module 220. The touch screen 228 can be integrated with the HX card 222, for example, in a tablet computer style device.

[0083] Each heat exchanger 118a, 118b can have one or more respective shutoff valves 224 that are controllable by the HX card 222. Therefore, each heat exchanger 118a, 118b within the heat transfer module 220 is selectively individually openable or closable by the HX card 222. In the examples shown, there are four shutoff valves 224 across each heat exchanger 118a, 118b.

[0084] The various sensors can be used to detect and transmit measurement of parameters of the heat transfer module 220. The sensors can include temperature sensors for Temperature Source, In (TSource, In); Temperature Source, Out (TSource, In); Temperature Load, Out (TLoad, Out); Temperature Load, In (TLoad, In). The temperature sensors can further include temperature sensors, one each for respective Temperature output of the source and load fluid path of each heat exchanger 118a, 118b (four total in this example). Therefore, eight total temperature sensors can be used in the example heat transfer module 220.

[0085] The sensors can also include sensors for: Differential Pressure between Source, In and Source, Out; Differential Pressure between Load, In and Load, Out;Pressure at Source, In; Pressure at Load, In. More or fewer of the sensors can be used invarious examples, depending on the particular parameter or coefficient being detected or calculated, as applicable. Such sensors can be contained within the sealed casing (frame 200). In some examples, the sensors include flow sensors (also called flow metering devices) for: Flow, source (Fsource); and Flow, load (Fload), which are typically external to the heat transfer module 220.

[0086] Figure 3A illustrates a graphical representation of network connectivity of a heat transfer system 300, having local system setup. The heat transfer system 300 includes a Building Automation System (BAS) 302 that can include the controllers 116 (Figures 1A and 1B). The BAS 302 can communicate with the control pumps 102a, 102b and the heat transfer module 220 by a router 306 or via short-range wireless communication. A smart device 304 can be in communication, directly or indirectly, with the BAS 302, the control pumps 102a, 102b and the heat transfer module 220. The smart device 304 can be used for commissioning, setup, maintenance, alert / notifications, communication and control of the control pumps 102a, 102b and the heat transfer module 220. In examples, the smart device 304 can be a smart phone or mobile communication device.

[0087] Figure 3B illustrates a graphical representation of network connectivity of a heat transfer system 320, having remote system setup. The BAS 302 can communicate with the control pumps 102a, 102b and the heat transfer module 220 by a router 306 or via short-range wireless communication. The smart device 304 can access, by way of Internet connection, one or more cloud computer servers over the cloud 308. The smart device 304 can be in communication, directly or indirectly with the BAS 302, the control pumps 102a, 102b and the heat transfer module 230 over the cloud 308. The smart device 304 can be configured for commissioning, setup, maintenance, alert / notifications, communication and control of the control pumps 102a, 102b and the heat transfer module 230. The cloud servers store an active record of measurement of the various equipment, and their serial numbers. When maintenance and service is required, records and notes can be viewed. This can be part of a service application (“app”) for the smart device 304.

[0088] Each heat transfer module 230 can have a HX card 222. A function of the HX card 222 is to connect to all sensors and devices on the heat transfer module 230either through a physical connection (Controller Area Network (CAN) bus or direct connection) and / or wirelessly. The HX card 222 can also collect information from the pump PC card 226 either through a physical connection or wirelessly.

[0089] The HX card 222 gathers all of the sensor measurement and other information and processes it and controls the flow required to the source side control pump 102b. The HX card 222 also sends sensor readings to the source side control pump 102b and the load side control pump 102a so that they can display real-time information on their respective display screens(s). The HX card 222 can also send the sensor measurement information to the Cloud 308. In an example, all heat exchanger related calculations can be handled by the HX card 222 for more immediate processing. In an example, the other devices can be configured as devices for displaying data previous calculated by the HX card 222.

[0090] The user can modify settings by connecting to the HX card 222 locally using the wireless smart device 304 or the BAS 302. The user can also modify limited settings remotely by connecting to the Cloud 308. These settings will be limited depending on security restrictions.

[0091] When the HX card 222 and the control pumps 102a, 102b are connected through the router 306, then the smart device 304, the PC card 226 and the HX card 222 can communicate using the router 306. When the HX card 222 and the control pumps 102a, 102b are not connected through on the router 306, then the HX card 222 can automatically open a WIFI hotspot for communication between the smart device 304, PC card 226 and HX card 222. When the HX card 222 opens the WIFI hotspot, communication to the Cloud 308 can occur either through the built in loT card, Ethernet connection, SIM card, etc.

[0092] The PC card 226 can connect to the HX card 222 either wirelessly or through a physical connection and provide the HX card 222 with pump sensor data. The PC card 226 can receive data from the HX card 222 (measurement, alerts, calculations) to be displayed on the pump display screen.

[0093] The PC card 226 can communicate to the HX card 222 wirelessly using the ModBUS protocol, as understood in the art. Other protocols can be used in otherexamples. For communication to occur between the PC card 226 and the HX card 222, the IP addresses of the PC card 226 and the HX card 222 need to be known. Internal identifiers can also be built into the PC card 226 and the HX card 222 such that they can find each other easily on a local area network. The PC card 226 can send information to other devices and accepting information and control from other devices.

[0094] The BAS 302, when used, can connect to the HX card(s) 222 and the PC card(s) 226 wirelessly through the router or through a direct connection. In an example, the BAS 302 has the highest control permissions and can override the HX card(s) 222 and the PC card(s) 226.

[0095] The HX card 222 provides to the Cloud 308 historic measurement data for storage. There can an application on the smart device 304 where the user can view data and generate reports. The Cloud 308 can use historic data to create reports and provide performance management services.

[0096] The smart device 304 can connect locally through the router 306 to the HX card 222 to modify settings. The smart device 304 can also connect to the Cloud 308 where the user can modify a limited number of settings, in an example.

[0097] An application (App), webserver user interface, and / or website can be included so that the user has all the functionality available on the PC card 226 or the Cloud 308.

[0098] The heat transfer system 300, 320 can be configured to provide information to users through the PC card 226, and remotely through online services and a control pump manager. The inputs to the HX card 222 can collect readings and measurements from the two temperature sensors on the cold side fluid and the two temperature sensors on the hot side fluid across the entire heat transfer module 230. Duplex and triplex heat transfer modules 220, 230 can have additional temperature sensors on the outlets of each individual heat exchanger 118a, 118b, 118c to calculate the temperature difference across the single heat exchanger 118a, 118b, 118c. The absolute temperature difference between the two temperature sensors is called the delta T. The HX card 222 and PC card 226 can communicate in real time and provide the data to the Cloud 308 for data logging and processing.

[0099] The heat transfer system 300, 320 can operate using demand based controls. Changes in the heat load in the building (load side, in general) will result in changes in flow requirement. In some examples, the control pump(s) 102a on load side will adjust speed to meet the flow requirement in real time based on sensorless (e.g., parallel or coordinated sensorless) operation. In some examples, the control pump 102a calculates the flow in real time and the HX card 222 gets signals from temperature sensors installed on inlet and outlet of heat exchanger(s) 118. The temperature difference is calculated in real time on the HX card 222 and together with flow used to calculate heat load (Q) required in the system load 110a, 110b, 110c, 110d of the building 104 in real time.

[0100] The HX card 222 calculates the optimal flow and temperatures on the source side to achieve the most energy efficient system operation. The source side fluid flow can be controlled by various methods of heat transfer loop control.

[0101] The heat transfer system 300, 320 can monitor the amount of time the system operates at part loads and full loads (duty load) and, when the part load operating time exceeds a set time limit, can operate the control pumps 102a, 102b at full load flow to automatically flush the heat exchanger 118. Operating the pumps at full load flow activates the heat exchanger's 118 self-cleaning ability. This feature is programmed with parameters of cleaning frequency of self-cleaning hours per run time hours and time of day start for self-cleaning. An example default self-cleaning, full load flow operating time is 30 minutes for every 168 hours (7 days) of part load operating time at 3am in the morning. The default part load threshold is set at 90% of full load flow (duty flow).

[0102] In some examples, the user has access to sensor readings on the HX card 222. Connected control pumps 102a, 102b can display real time sensor data on their respective display screens(s). The HX card 222 uploads historic sensor data to the Cloud 308 where the user can access the sensor data.

[0103] In some examples, the HX card 222 can enable heat transfer algorithms (e.g., various heat transfer loop control), real time fouling tracking, and real time error monitoring and maintenance tracking.

[0104] The PC card 226 can communicatively connect to the HX card 222 and display, on the touch screen of the respective control pump 102a, 102b, additional trending, fouling tracking, and maintenance record information. The Cloud 308 can monitor the information and performance reports and error tracking to the customer with current usage, savings, and recommended actions.

[0105] The HX card 222 can store individual heat exchanger data, such as heat transfer module model and serial numbers, design points, mapped heat transfer performance curves (U value as a function of flow). Mapped data of heat transfer curves to be tested in house for each individual heat exchanger 118.

[0106] Service history can be stored on the Cloud 308. Service history can be upload to the HX card 222 through Webserver III, PC card 226, or Cloud 308. If the Cloud 308 does not have the most up to date version then the HX card 222 can push the records to the Cloud 308. If the Cloud 308 has the most up to date version, the Cloud 308 can push the record to the HX card 222.

[0107] For the HX card 222, in some examples, data sampling (inlet and outlet temperatures and pressure of hot and cold side, hot and cold side flow) can be taken every minute up to but not longer than every 5 minutes. Data can be regularly updated and stored on the Cloud 308. All inputs and calculated parameters can be updated as per the sampling time and can be shown on the display screen of the control pump 102a, 102b. The calculated parameters include, delta T, differential pressure, flow, lldirt (overall heat transfer coefficient of heat exchanger after some time of operation), and the heat exchanged (calculated for both the source and load side fluids), total pumping energy, and system efficiency (heat exchanged divided by the total pumping energy, shown in units of Btu / h in imperial and kW in metric).

[0108] Example various controls operations (flow control modes) of the heat transfer system 300, 320 are as follows. 1. Constant speed control. 2. Tsource, out control (Feed Forward Control Mode or Method). 3. Tload, out control (Feed Forward Control Mode). 4. Proportional Flow Matching. 5. Maximize Source Side Delta T with constant temperature approach and constant load side Delta T. 6. Maximize Source Side Delta T with variable temperature approach and variable load side Delta T. 7. Low Source Delta T Mitigation Method (or feature).

[0109] Some examples of the various control operations (flow control modes) are described in, for example, PCT Application No. PCT / CA2019 / 051428 filed October 4, 2019, the entire contents of which are herein incorporated by reference.

[0110] Referring to the heat transfer system 300, 320 in Figure 3A and Figure 3B, in an example, the controllers 116 are configured to switch between one or more of these seven types of flow control modes. In some examples, at least one of the control modes is a feed forward control. In some examples, at least one of the control modes is a feedback control. For example, the controllers 116 are configured to switch to, or from, one type of the flow control mode to or from a different second type of flow control mode.

[0111] In an example, the decision by the controllers 116 to switch to a different control mode is based on the sensed information from one or more of the sensors of the environment, for example as operating conditions change, or as parts of the system degrade or fail. In some cases, for example, when sensor information from one or more sensors is no longer available, the control mode is switched to a flow control mode of operation that does not require data from those one or more sensors. In some examples, the flow control mode that is selected by the controllers 116 is the flow control mode that best maintains constant load side temperature. In some examples, the flow control mode that is selected by the controllers 116 is the flow control mode that minimized energy consumed for the heat load transferred.

[0112] In other examples, the decision by the controllers 116 to switch control modes is rule based, such as time of day, particular season of the year, for maintenance, manual control, etc.

[0113] Referring again to Figure 1A, the pump device 106a may take on various forms of pumps which have variable speed control. In some example embodiments, the pump device 106a includes at least a sealed casing which houses the pump device 106a, which at least defines an input element for receiving a circulation medium and an output element for outputting the circulation medium. The pump device 106a includes one or more operable elements, including a variable motor which can be variably controlled from the control device 108a to rotate at variable speeds. The pump device 106a also includes an impeller which is operably coupled to the motor and spins based on the speed of the motor, to circulate the circulation medium. The pump device 106a may further includeadditional suitable operable elements or features, depending on the type of pump device 106a. Some device properties of the pump device 106a, such as the motor speed and power, may be self-detected by an internal sensor of the control device 108a.

[0114] Referring again to Figure 1A, the control device 108a, 108b for each control pump 102a, 102b may include an internal detector or sensor, typically referred to in the art as a “sensorless” control pump because an external sensor is not required. The internal detector may be configured to self-detect, for example, device properties such as the power and speed of the pump device 106a. Other input variables may be detected. The pump speed of the pump device 106a, 106b may be varied to achieve a pressure and flow setpoint, or a temperature and heat load setpoint, of the pump device 106a in dependence of the internal detector. A program map may be used by the control device 108a, 108b to map a detected power and speed to resultant output properties, such as head output and flow output, or temperature output and heat load output.

[0115] The relationship between parameters may be approximated by particular affinity laws, which may be affected by volume, pressure, and Brake Horsepower (BHP) (hp I kW). For example, for variations in impeller diameter, at constant speed: D1 / D2 = Q1 / Q2; H1 / H2 = D12 / D22; BHP1 / BHP2 = D13 / D23. For example, for variations in speed, with constant impeller diameter: S1 / S2 = Q1 / Q2; H1 / H2 = S12 / S22; BHP1 / BHP2 = S13 / S23. Wherein: D = Impeller Diameter (Ins I mm); H = Pump Head (Ft / m); Q = Pump Capacity (gpm I Ips); S = Speed (rpm I rps); BHP = Brake Horsepower (Shaft Power - hp / kW).

[0116] Variations may be made in example embodiments. Some example embodiments may be applied to any variable speed device, and not limited to variable speed control pumps. For example, some additional embodiments may use different parameters or variables, and may use more than two parameters (e.g. three parameters on a three dimensional map, or N parameters on a N-dimensional map). Some example embodiments may be applied to any devices which are dependent on two or more correlated parameters. Some example embodiments can include variables dependent on parameters or variables such as liquid, temperature, viscosity, suction pressure, site elevation and number of devices or pump operating.

[0117] Another example of the automatic maintenance and flushing is performed by the controllers 116 (which may include processing performed by the HX card 222 in an example). For example, the controllers 116 determine that maintenance (i.e. flushing) is required on the heat exchanger 118 based on real-time operation measurement when satisfying the system load 110a, 110b, 110c, 110d. For example, the controllers 116 perform automatic maintenance (flushing) on the heat exchanger 118 by controlling flow to a maximum flow. In various examples, maximum flow be can controlling of the control pumps 102a, 102b to their respective maximum flow capacity, or a maximum flow that is supported by the load 110a, 110b, 110c, 110d (i.e., duty load), or a maximum flow capacity of the heat exchanger 118. The maximum flow is used to flush the fouling in the heat exchanger 118. In example embodiments, the automatic maintenance (flushing) can be performed during real-time operation to satisfy the system load 110a, 110b, 110c, 110d, with appropriate compensation to account for the increase in flow. If flushing is not successful, the controllers 116 alert another device such as the BAS 302 or the smart device 304 that manual inspection, repair or replacement of the heat exchanger 118 is required.

[0118] The success or non-success of the maintenance can be calculated using a similarity parameter, in some example embodiments.

[0119] Figure 4A shows an example graph 400 which illustrates an example method for the controller 116 determining whether the heat exchanger 118 is fouled, or critically fouled. The method illustrated by the graph 400 is performed upon initial setup of the heat exchanger 118, and after each cleaning by the one or more control pumps 102a, 102b on the heat exchanger 118.

[0120] In the method of Figure 4A, the following definitions are used.

[0121] Simplex unit: a unit with only one heat exchanger 118 (e.g., a heat transfer module).

[0122] Duplex unit: a unit with two heat exchangers piped in parallel (e.g., heat transfer module 220, Figure 2B).

[0123] Triplex unit: a unit with three heat exchangers piped in parallel (e.g., heat transfer module 230, Figure 2C-2E).

[0124] Reference is made to Equation 1:MRe = density0 75x flow1-75x viscosity025Equation 1

[0125] Where:

[0126] density: density of the fluid [kg / m3] (temperature dependent)

[0127] viscosity: viscosity of the fluid (temperature dependent) [

[0128] flow: volumetric flow rate through each heat exchanger [m3 / s],

[0129] Equation 1 calculates a similarity parameter, also referred to as a modified Reynolds number (MRe) or a viscous-density parameter used to normalize pressure drop overflow rate, fluid viscosity and density. The graph 704-04 illustrates pressure drop (DP) versus the modified Reynolds number (MRe). The graph 400 includes a CLEAN curve 402, an INITIAL curve 404, and a POST-CLEAN point 406. In an example, as shown, the curves can be straight lines. In other examples, the curves are not straight lines (e.g., best fits, polynomials, models, etc.). In other examples, the curves are functions that are stored as ordered pairs or ordered sets. In an example, inference is performed for the plotted points, such as straight line interpolation or extrapolation as between two of the plotted points, or other various forms.

[0130] An example of the method is the detection of fouling in heat exchangers 118, such as plate-and-frame or brazed-plate heat exchangers 118. The method utilizes a systematic initialization and monitoring process to establish and maintain a baseline performance metric (parameter) in terms of pressure drop for fouling detection. During initial startup, pressure differential across the HX (DP) data is collected for varying flow rate (for each heat exchanger 118 in cases where more than one heat exchanger are running in parallel). The pressure drop values versus a similarity parameter, also called MRe (modified Reynolds number), are plotted and saved as an initial reference curve (INITIAL curve 404). Post-cleaning, the method dynamically adjusts this reference curve based on deviations observed during operation, effectively accounting for residual fouling effects (CLEAN curve 402 with POST-CLEAN point 406).

[0131] The method includes automated valve control, sensor feedback integration, and real-time performance monitoring. By recalibrating pressure drop (DP) baselinespost-cleaning while preserving initial startup values, the method ensures accurate fouling detection and efficient heat exchanger operation. The method includes calculating a similarity parameter normalized the pressure drop the pressure drop across a heat exchanger over flow rate, fluid viscosity and fluid density. This method reduces the need for manual recalibration after cleaning cycles, improving system reliability and reducing maintenance costs. In examples, the method is applicable to simplex and multiplex heat exchanger configurations and enhances operational efficiency by continuously adapting to changing system conditions.

[0132] The method is explained in the form an algorithm for the controller 116 as follows:

[0133] 1. (LOOP-1 - startup loop) At the time of unit start up, an alarm will be shown in the alarms section mentioning that the until hasn’t been initialized and startup steps are not completed, this error message remains active until LOOP-1 is completed and all the required data is saved. An example text for the alarm message: “Unit initialization process is not complete, please put actuated valves and pumps in the auto mode and ensure there is no obstruction for full design flow on the primary and secondary loops then press below button to perform the initialization, fouling detection features will not work until the initialization process is complete.”

[0134] 1.1. For duplex and triplex units, close the actuated valves on both sides of all HXs except HX-1. (skip this step for simplex units).

[0135] 1.2. 5 sec. after the valve position feedbacks are received (i.e. valves are confirmed closed), set both side flows to 50% of the design max flow for one HX (e.g. in a triplex unit, max flow for one HX is max flow of the unit, divided by 3).

[0136] 1.3. 5 sec. after the flow reading is within a + / - 2.5% band around setpoint, for both source and load sides obtain the DP sensor reading and the temperature reading of the fluid at the inlet and outlet of HX-1 (for calculating the average temperature of inlet and outlet to be used for thermophysical properties of fluids).

[0137] 1.4. Calculate the MRe using Equation 1 above and save the MRe and DP as a set of data separately for each side {CLEAN[MRe(50%),DP(50%)]}.

[0138] 1.5. Repeat steps 1.2 to 1.4 for flows between 60% and 100% with 10% increments.

[0139] 1.6. Repeat steps 1.1 to 1.5 for HX-2 and HX-3. (skip this step for simplex units).

[0140] 1.7. Copy all the sets of data saved above to another array called initial: CLEAN[MRe(XX%),DP(XX%)]=INITIAL[MRe(XX%),DP(XX%)].

[0141] The reason for step 1.7 is to keep the startup values from being overwritten after the cleaning cycles and use them for fouling detection purposes.

[0142] 2. (LOOP-2 - Post-Cleaning Loop for simplex units) After a round of cleaning / flushing is completed and the unit is operational again:

[0143] 2.1. Continuously monitor the unit’s flow on load and source side on an adjustable time interval (default time interval = 1min), If the unit’s flow is between 60% and 90% of the design max flow for one HX on either side then:

[0144] 2.2. Obtain the DP sensor reading across the HX and the temperature readings at the inlet and outlet of the HX (average temp, of inlet and outlet is used to calculate the fluid properties).

[0145] 2.3. Calculate the MRe number for both source and load sides of HX using equation 1 and save the MRe and DP as a set of data {POST-CLEAN[MRe(XX%),DP(XX%)]}, see POST-CLEAN point 406.

[0146] 2.4. Compare the DP obtained in 2.3 with the previous clean DP for the same MRe (inference such as modelling, interpolation or extrapolation may be required). Increase all the clean DPs by the same percentage. For example, if a measured postclean DP is 11 psi (75842.3 Pa) and the MRe number calculated for it is 2000 and DP for MRe=2000 from previous sets of clean data is 10 psi (68947.6 Pa), then increase the DP by 10% on all the clean sets of data and save as new clean values. For example:CLEAN[MRe(XX%),DP(XX%)]=CLEAN[ MRe(XX%) , 1.1 x DP(XX%)]. Therefore, the previous CLEAN curve is scaled to the new CLEAN MRe data point.

[0147] Refer to Figure 4A for a graph 704-1 of step 2.4 and note that the INITIAL curve remains unchanged but CLEAN curves are adjusted after each cleaning cycle is completed.

[0148] 3. (LOOP-3 - Post-Cleaning Loop for multiplex units) After cleaning is completed for all HXs:

[0149] 3.1. Continuously monitor the unit’s flow on load and source side on an adjustable time interval (default time interval = 5m in)

[0150] 3.2. If the unit’s flow is between 60% and 90% of the design max flow for one HX on either side then override the normal HX staging, freeze the flow rate and perform steps 3.3 to 3.7:

[0151] 3.3. Close the actuated valves on both sides of all HXs except HX-1.

[0152] 3.4. 5 sec. after the valve position feedbacks are received, obtain the DP sensor reading across the HX-1 and the temperature readings at the inlet and outlet of HX-1 (average temp, of inlet and outlet is used to calculate the fluid properties).

[0153] 3.5. Calculate the MRe number for both sides of HX-1 using equation 1 and save the MRe and DP as a set of data {POST-CLEAN[MRe(XX%),DP(XX%)]}, see POST-CLEAN point 406.

[0154] 3.6. Compare the DP obtained in 3.5 with the previous clean DP for the same MRe (inference such as modelling, interpolation or extrapolation may be required). Increase all the clean DPs by the same percentage. For example, if a measured postclean DP is 11 psi (75842.3 Pa) and the MRe number calculated for it is 2000 and DP for MRe=2000 from previous sets of clean data is 10 psi (68947.6 Pa), then increase the DP by 10% on all the clean sets of data and save as new clean values.CLEAN[Re(XX%),DP(XX%)]=CLEAN[ Re(XX%) , 1.1 x DP(XX%)].

[0155] Refer to the graph 400 in Figure 4A for a graphic demonstration of step 3.6 and note that the INITIAL curve 404 remains unchanged but the CLEAN curve(s) 402 are moved after each cleaning / flushing cycle is completed.

[0156] Repeat steps 3.3 to 3.6 for HX-2 and HX-3 and then Terminate Loop-3 and return to normal operation.

[0157] 4. Continuously monitor the difference between the clean DP and INITIAL DP for MRe(100%), for both sides of all HXs, if the clean DP is higher than INITIAL DP by more than 30% flag that side of that HX as fouled and if the clean DP is higher than INITIAL DP by more than 50% flag that side of that HX as critically fouled. Normally a fouled heat exchanger 118 that can not be cleaned by flushing / back flushing needs to go through a full overhaul by disassembling or acid washing. In an example, these thresholds are user adjustable.

[0158] The controller 116 can alert of the critical fouling.

[0159] The MRe is a similarity parameter. Note that the MRe in Equation 1 is not dimensionless. The MRe parameter is used to normalize the pressure drop over the operating ranges of viscosity and density values and flow rates. When there are two scenarios with different temperatures (therefore different thermophysical properties such as viscosity and density) and different flows, if MRe is the same one can expect that pressure drop should be the same for those two scenarios although flow and thermophysical properties are different. For example, MRe = f(DP V design temperature, design pressure, design flow, design density, design viscosity).

[0160] The similarity parameter allows (and defines) the pressure drop to be comparable for all operating ranges of the flow rate, the fluid viscosity and the fluid density of the fluid.

[0161] Figure 4B shows an example of a method 1000 performed for initializing a heat transfer module 220, 230 (having one or more heat exchangers 118) for the method of the graph 400 illustrated in Figure 4A. The method 1000 is an example of Loop-1 (for each fluid circuit). Figure 4C shows an example of a method 1100 performed after each cleaning of the heat transfer module 220, 230 for the method of the graph 400 illustrated in Figure 4A. The method 1100 is an example of Loop-2 or Loop-3 with alert (for each fluid circuit). In an example, the method 1000 and the method 1100 can be performed by at least one controller.

[0162] Referring to Figure 4B, at step 1002, the heat transfer module 220, 230 is initialized, being prior to or just installed into the building system 100. A loop begins at step 1004 if there is more than one heat exchanger 118 in the heat transfer module 220,230. At step 1004, open the respective valves 224 for one heat exchanger 118. At step 1005, set Flow (F) to 50% of maximum design flow. At step 1006, for a given Flow (F) (e.g. 50% of maximum design flow for the first iteration of the Ioo0070), receive data of Flow (F), Temperature IN (Tin), Temperature Out (Tout), and Delta pressure across the heat exchanger (DP). At step 1008, calculate MRe (Equation 1). At step 1010, store the point post-clean{MRe(F), DP(F)}. The Flow (F) can be increase by 10% increments until the flow is at 100%. At step 1012 determine whether the flow is 100%, and therefore the desired calculations of MRe have now been completed. If No, then at step 1013 increase Flow (F) by 10%, and then loop to step 1006 until 100% is reached. If Yes, then proceed to step 1014. At step 1014, if there is more than one heat exchanger 118 in the heat transfer module 220, 230, repeat the loop starting at step 1006 for the next heat exchanger 118 in the heat transfer module 220, 230. In examples, steps 1004 to 1014 can also be performed during real-time satisfying of a load.

[0163] At step 1016, store the array Clean[MRe(F), DP(F)] for the clean state. At step 1018, store the array Clean[MRe(F), DP(F)] as array lnitial[MRe(F), DP(F)] so that the array lnitial[] can be used for future calculations. The array Clean[] and the array In itial[] can also be stored or generated into functions, best fit models, curves, inferences, etc. Referring briefly to Figure 4A, the initial curve 404 (array lnitial[]) is shown (which also currently equals the clean curve (array Clean[])). At step 1020, per normal operation, the heat transfer module 220, 230 operates within the building system 100 to source the load.

[0164] Referring to Figure 4C, the heat transfer module 220, 230 may be cleaned by flushing (e.g. by the control pumps operating at maximum flow) or by manual cleaning. At step 1102, the cleaning is completed. At step 1103, determine that (and wait if needed) the system flow is within a given set range such as 60%-90% of maximum design flow, then freeze the flow (by controlling the control pumps or by detecting a relatively consistent flow period). At step 1104, a loop beings if there is more than one heat exchanger 118 in the heat transfer module 220, 230. At step 1104, open the respective valves 224 for one heat exchanger 118. At step 1106, receive data indicative of Flow (F), Temperature IN (Tin), Temperature Out (Tout), and Delta pressure across the heat exchanger (DP). At step 1108, calculate MRe (Equation 1). At step 1110, storethe point post-clean{MRe(F), DP(F)}. At step 1112, scale the previous array Clean[] to the new point post-Clean{} and store the new array Clean[], The new array Clean[] can be used for future iterations of the method 1100. Referring briefly to Figure 4A, there is shown the initial curve 404 (array lnitial[]), the POST-CLEAN point 406 (post-clean point {MRe(F), DP(F)}), and the new clean curve 402 (new array Clean[])).

[0165] At step 1114, if there is more than one heat exchanger 118 in the heat transfer module 220, 230, repeat (loop) to step 1104 for the next heat exchanger 118 in the heat transfer module 220, 230. In examples, steps 1004 to 1014 can also be performed during real-time satisfying of a load.

[0166] At step 1116, compare a point at maximum design flow (F = 100%) from the array Clean[MRe(F), DP(F)] to the array lnitial[MRe(F), DP(F)]. Inference or other calculations may be required in some examples. At step 1118, if the percentage difference exceeds a threshold, then send an alert (step 1120). If the percentage difference is within the threshold, then proceed to normal operation of the heat transfer module 220, 230 (step 1122). In an example, the threshold is user adjustable.

[0167] An example embodiment is a method for a heat transfer module 220, 230 for connection to a first fluid circuit and a second fluid circuit and configured for flow of at least one fluid, wherein the heat transfer module 220, 230 includes at least one heat exchanger 118, the method being performed by at least one controller and comprising: receiving data indicative of measurement of flow, temperature, and pressure drop of the at least one fluid; calculating, for each heat exchanger 118 based on the data, a similarity parameter that normalizes the pressure drop across that heat exchanger 118 over flow rate, fluid viscosity and fluid density; and generating, for each heat exchanger 118, a function of the pressure drop versus the similarity parameter.

[0168] In another example embodiment of any of the above, the calculating comprises calculating:similarity parameter = density0 75x flow1 75x viscosity0 25(Equation 1); wherein:density = density of one fluid of the at least one fluid,viscosity = viscosity of the fluid, andflow = volumetric flow rate of fluid through the heat transfer module 220, 230.

[0169] In another example, the maintenance to the heat exchanger 118 is only applied to one fluid path.

[0170] In another example, the maintenance to the heat exchanger 118 can be delayed until a suitable off-hours time, such as the weekend or after business hours, where variable changes in flow for the maintenance will be less noticeable and the instantaneous load 110a, 110b, 110c, 110d is more predictable.

[0171] Another example embodiment is a system, comprising at least one controller for performing the method of any one of the above.

[0172] Another example embodiment is a non-transitory computer readable medium having instructions stored thereon executable by at least one controller for performing the method of any one of the above.

[0173] In example embodiments, as appropriate, each illustrated block or module may represent software, hardware, or a combination of hardware and software. Further, some of the blocks or modules may be combined in other example embodiments, and more or fewer blocks or modules may be present in other example embodiments.Furthermore, some of the blocks or modules may be separated into a number of subblocks or sub-modules in other embodiments.

[0174] While some of the example embodiments are described in terms of methods, a person of ordinary skill in the art will understand that example embodiments are also directed to various apparatus such as a server apparatus including components for performing at least some of the aspects and features of the described methods, be it by way of hardware components, software or any combination of the two, or in any other manner. Moreover, an article of manufacture for use with the apparatus, such as a prerecorded storage device or other similar non-transitory computer readable medium including program instructions recorded thereon, or a computer data signal carrying computer readable program instructions may direct an apparatus to facilitate the practice of the described methods. It is understood that such apparatus, articles of manufacture, and computer data signals also come within the scope of the example embodiments.

[0175] While some of the above examples have been described as occurring in a particular order, it will be appreciated to persons skilled in the art that some of the messages or steps or processes may be performed in a different order provided that the result of the changed order of any given step will not prevent or impair the occurrence of subsequent steps. Furthermore, some of the messages or steps described above may be removed or combined in other embodiments, and some of the messages or steps described above may be separated into a number of sub-messages or sub-steps in other embodiments. Even further, some or all of the steps of the conversations may be repeated, as necessary. Elements described as methods or steps similarly apply to systems or subcomponents, and vice-versa.

[0176] In example embodiments, the one or more controllers can be implemented by or executed by, for example, one or more of the following systems: Personal Computer (PC), Programmable Logic Controller (PLC), Microprocessor, Internet, Cloud Computing, Mainframe (local or remote), mobile phone or mobile communication device.

[0177] The term "computer readable medium" as used herein includes any medium which can store instructions, program steps, or the like, for use by or execution by a computer or other computing device including, but not limited to: magnetic media, such as a diskette, a disk drive, a magnetic drum, a magneto-optical disk, a magnetic tape, a magnetic core memory, or the like; electronic storage, such as a random access memory (RAM) of any type including static RAM, dynamic RAM, synchronous dynamic RAM (SDRAM), a read-only memory (ROM), a programmable-read-only memory of any type including PROM, EPROM, EEPROM, FLASH, EAROM, a so-called "solid state disk", other electronic storage of any type including a charge-coupled device (CCD), or magnetic bubble memory, a portable electronic data-carrying card of any type including COMPACT FLASH, SECURE DIGITAL (SD-CARD), MEMORY STICK, and the like; and optical media such as a Compact Disc (CD), Digital Versatile Disc (DVD) or BLU-RAY (TM) Disc.

[0178] Variations may be made to some example embodiments, which may include combinations and sub-combinations of any of the above. The various example embodiments are merely examples and are in no way meant to limit the scope of the example embodiments. Variations of the innovations described herein will be apparent topersons of ordinary skill in the art having the benefit of the described examples, such variations being within the intended scope of the example embodiments. In particular, features from one or more of the above-described embodiments may be selected to create alternative embodiments comprised of a sub-combination of features which may not be explicitly described above. In addition, features from one or more of the abovedescribed embodiments may be selected and combined to create alternative embodiments comprised of a combination of features which may not be explicitly described above. Features suitable for such combinations and sub-combinations would be readily apparent to persons skilled in the art upon review of the example embodiments as a whole. The subject matter described herein intends to cover all suitable changes in technology.

[0179] Certain adaptations and modifications of the described embodiments can be made. Therefore, the above discussed embodiments are considered to be illustrative and not restrictive.

Claims

WHAT IS CLAIMED IS:

1. A method for a heat transfer module for connection to a first fluid circuit and a second fluid circuit and configured for flow of at least one fluid, wherein the heat transfer module includes at least one heat exchanger, the method being performed by at least one controller and comprising:receiving data indicative of measurement of flow, temperature, and pressure drop of the at least one fluid;calculating, for each heat exchanger based on the data, a similarity parameter that normalizes the pressure drop across that heat exchanger overflow rate, fluid viscosity and fluid density; andgenerating, for each heat exchanger, a function of the pressure drop versus the similarity parameter.

2. The method as claimed in claim 1 , wherein the calculating comprises calculating: similarity parameter = density0 75x flow1 75x viscosity0 25(Equation 1);wherein:density = the fluid density of one fluid of the at least one fluid,viscosity = the fluid viscosity of the one fluid, andflow = the flow of the one fluid through the heat transfer module.

3. The method as claimed in claim 2, wherein the fluid density of the one fluid and the fluid viscosity of the one fluid are dependent on the temperature.

4. The method as claimed in claim 1 , wherein the data is measured during real-time operation of the heat transfer module or during real-time operation by the heat transfer module to satisfy a load.

5. The method as claimed in claim 1 , wherein the data is measured at different flow values.

6. The method as claimed in claim 5, wherein the flow values include 50% of maximum design flow.

7. The method as claimed in claim 5, wherein the flow values include 50% to 100% of maximum design flow at 10% increments.

8. The method as claimed in claim 1 , wherein the similarity parameter defines the pressure drop so as to be comparable for all operating ranges of the flow rate, the fluid viscosity and the fluid density of the fluid.

9. The method as claimed in claim 1 , wherein the at least one heat exchanger comprises a plurality of heat exchangers in parallel, wherein the calculating and the generating is performed individually for each heat exchanger that has been activated one at a time.

10. The method as claimed in claim 1, wherein the calculating includes calculating a plurality of the similarity parameter at respective different pressure drop.

11. The method as claimed in claim 10, wherein the generating the function includes inferring from the plurality of similarity parameter at the respective different pressure drop.

12. The method as claimed in claim 1 , wherein the calculating of the similarity parameter is performed individually for a first fluid of the at least one fluid in the first fluid circuit and a second fluid of the at least one fluid in the second fluid circuit.

13. The method as claimed in claim 1 , further comprising determining, based on the comparison of previous pressure drops and current pressure drops for the similarity parameter, that the heat transfer module is fouled.

14. The method as claimed in claim 1 , wherein the function includes an ordered set, a model, a straight-line function, and / or a polynomial function.

15. The method as claimed in claim 1, wherein the calculating and the generating is for an initial state of the at least one heat exchanger prior to operation in a heat transfersystem or at or prior to installation in the heat transfer system, and wherein the function includes an initial function for the initial state.

16. The method as claimed in claim 15, wherein the heat transfer system includes a chilled water process, space cooling system, a hot water process, and / or space heating system.

17. The method as claimed in claim 15, wherein the calculating and the generating is for a clean state of the at least one heat exchanger after cleaning or flushing of the at least one heat exchanger, further comprising recording a set of data including a postclean similarity parameter at a post-clean pressure drop for the clean state, and wherein the function includes a post-clean function for the clean state.

18. The method as claimed in claim 17, wherein the generating the clean function includes mathematically scaling the initial function to the post-clean pressure drop at the post-clean similarity parameter.

19. The method as claimed in claim 17, wherein the generating the clean function includes mathematically scaling a previous clean function to the post-clean pressure drop at the post-clean similarity parameter.

20. The method as claimed in claim 17, further comprising determining that a percentage difference of the post-clean function to the initial function exceeds a threshold, and in response to the determining, generating an alert of a fouling of the heat transfer module.

21. The method as claimed in claim 20, wherein the threshold is user adjustable.

22. The method as claimed in claim 15, wherein the initial function is inferred.

23. The method as claimed in claim 15, wherein the calculating is for a clean state of the at least one heat exchanger after cleaning or flushing of the at least one heat exchanger, wherein the similarity parameter includes a post-clean similarity parameter at a post-clean pressure drop for the clean state, further comprising determining that a percentage difference of the post-clean pressure drop at the post-clean similarityparameter to the initial pressure drop at the post-clean similarity parameter exceeds a threshold.

24. The method as claimed in claim 23, wherein the determining of the percentage difference of the post-clean pressure drop at the post-clean similarity parameter to the initial pressure drop at the post-clean similarity parameter is determined for maximum design flow, and in response to the determining, generating an alert of a fouling of the heat transfer module.

25. The method as claimed in claim 23, wherein the threshold is user-adjustable.

26. The method as claimed in claim 1 , wherein the at least one controller is attached to or part of the heat transfer module.

27. The method as claimed in claim 1 , wherein the at least one controller is separate from the heat transfer module.

28. A method for an apparatus configured to have flow of at least one fluid, the method being performed by at least one controller and comprising:calculating, for the apparatus, a similarity parameter of a fluid of the at least one fluid that normalizes the pressure drop across the apparatus over flow rate, fluid viscosity and fluid density; andgenerating, for the apparatus, a function of the pressure drop versus the similarity parameter.

29. The method as claimed in claim 28, wherein the similarity parameter defines the pressure drop so as to be comparable for all operating ranges of the flow rate, the fluid viscosity and the fluid density of the fluid.

30. The method as claimed in claim 28, wherein the calculating includes calculating a plurality of the similarity parameter at respective different pressure drop.

31. The method as claimed in claim 28, wherein the calculating comprises calculating: similarity parameter = density075x flow175x viscosity025(Equation 1);wherein:density = the fluid density of one fluid of the at least one fluid,viscosity = the fluid viscosity of the one fluid, andflow = the flow of the one fluid through the apparatus.

32. The method as claimed in claim 31 , wherein the fluid density of the one fluid and the viscosity of the one fluid are dependent on temperature.

33. The method as claimed in claim 28, further comprising receiving data indicative of measurement of flow, temperature, and the pressure drop of the apparatus, wherein the calculating uses the data.

34. The method as claimed in claim 33, wherein the data is measured during real-time operation of the apparatus or during real-time operation by the apparatus to satisfy a load.

35. The method as claimed in claim 28, wherein the apparatus is a heat transfer module including at least one heat exchanger and configured for connection to a first fluid circuit and a second fluid circuit, wherein the calculating of the similarity parameter is performed individually for a first fluid of the at least one fluid in the first fluid circuit and a second fluid of the at least one fluid in the second fluid circuit.

36. The method as claimed in claim 35, wherein the at least one heat exchanger comprises a plurality of heat exchangers in parallel, wherein the calculating and the generating is performed individually for each heat exchanger that has been activated one at a time.

37. The method as claimed in claim 28, further comprising determining, based on comparison of previous pressure drops and current pressure drops for the similarity parameter, that the apparatus is fouled.

38. A method for an apparatus, the method being performed by at least one controller and comprising:calculating a similarity parameter:similarity parameter = density075x flow1-75x viscosity025(Equation 1);wherein:density = fluid density of a fluid through the apparatus;viscosity = fluid viscosity of the fluid; andflow = flow of the fluid through the apparatus.

39. The method as claimed in claim 38, further comprising generating, for the apparatus, a function of pressure drop of the fluid across the apparatus versus the similarity parameter through the apparatus.

40. The method as claimed in claim 39, further comprising determining, based on comparison of previous pressure drops and current pressure drops for the similarity parameter, that the apparatus is fouled.

41. The method as claimed in claim 39, wherein the similarity parameter defines the pressure drop so as to be comparable for all operating ranges of the flow rate, the fluid viscosity and the fluid density of the fluid.

42. The method as claimed in claim 39, wherein the calculating includes calculating a plurality of similarity parameter at respective different pressure drop.

43. The method as claimed in claim 39, further comprising receiving data indicative of measurement of flow, temperature, and the pressure drop of the apparatus, wherein the calculating uses the data.

44. The method as claimed in claim 43, wherein the data is measured during real-time operation of the apparatus or during real-time operation by the apparatus to satisfy a load.

45. The method as claimed in claim 38, wherein the apparatus is a heat transfer module including at least one heat exchanger and configured for connection to a first fluid circuit and a second fluid circuit, wherein the calculating of the similarity parameter isperformed individually for a first fluid in the first fluid circuit and a second fluid in the second fluid circuit.

46. The method as claimed in claim 45, wherein the at least one heat exchanger comprises a plurality of heat exchangers in parallel, wherein the calculating is performed individually for each heat exchanger that has been activated one at a time.

47. The method as claimed in claim 38, further comprising determining, based on comparison of previous pressure drops and current pressure drops for the similarity parameter, that the apparatus is fouled.

48. A heat transfer system, comprising:a heat transfer module, comprising:a sealed casing that defines a first port and a second port configured for connection to a first fluid circuit across the first port and the second port, and that defines a third port and a fourth port configured for connection to a second fluid circuit across the third port and the fourth port, andat least one heat exchanger within the sealed casing configured for connection to the first fluid circuit port and the second fluid circuit;a first differential pressure sensor configured to detect first pressure drop across the first fluid circuit of the heat transfer module;a second differential pressure sensor configured to detect second pressure drop across the second fluid circuit of the heat transfer module;a first temperature sensor configured to detect first temperature measurement of first input of the first fluid circuit of the heat transfer module;a second temperature sensor configured to detect second temperature measurement of first output of the first fluid circuit of the heat transfer module;a third temperature sensor configured to detect third temperature measurement of second input of the second fluid circuit of the heat transfer module;a fourth temperature sensor configured to detect fourth temperature measurement of second output of the second fluid circuit of the heat transfer module;a first flow metering device configured to detect first flow measurement of the first fluid circuit;a second flow metering device configured to detect second flow measurement of the second fluid circuit; andat least one controller configured to:receive data from the first differential pressure sensor, the second differential pressure sensor, the first temperature sensor, the second temperature sensor, the third temperature sensor, the fourth temperature sensor, the first flow metering device, and the second flow metering device, andperform the method as claimed in any one of claims 1 to 27.

49. The heat transfer system as claimed in claim 48, wherein the at least one heat exchanger comprises a plurality of heat exchangers in parallel.

50. The heat transfer system as claimed in claim 48, further comprising at least one respective valve for each heat exchanger.

51. A non-transitory computer readable medium having instructions stored thereon executable by at least one controller for performing the method as claimed in any one of claims 1 to 47.

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