LEAK DETECTION IN A FLUID COMPRESSION SYSTEM

专利摘要:
Methods and systems for leak detection in a fluid compression system using a purge system are described herein. In one embodiment, a method for leak detection includes determining, during a vacuum period, a non-condensable purge exhaust flow from a purge system integrated into a cooler unit. (10). The method comprises determining a differential pressure, the differential pressure based on a vacuum side pressure of the cooler unit (10), wherein the vacuum side pressure comprises at least one of a pressure a condenser (14) and a pressure of an evaporator (16). The method includes calculating, via a controller (82), the purge exhaust flow rate and the differential pressure to identify a leakage size based at least in part on the purge exhaust flow rate.
公开号:FR3058218A1
申请号:FR1760276
申请日:2017-10-31
公开日:2018-05-04
发明作者:Robert J. Roth
申请人:Trane International Inc；
IPC主号:

专利说明:

FIELD
This description generally relates to leak detection. This description relates more specifically to systems and methods for leak detection in a fluid compression system, where the fluid compression system is a heating, ventilation, air conditioning, and / or refrigeration (HVACR) system, which may include a cooler unit using a purge system.
BACKGROUND
Refrigerants, coolants, and / or combinations of working fluids flow through a cooling circuit, for example a heating, ventilation, air conditioning, and / or refrigeration (HVACR) system, which may include a cooler unit. Leaks in a chiller unit can degrade the system, compromise performance, and / or cause environmental problems. The refrigerant leak inspection generally includes an electronic leak detection wand, a bubble test, and / or a visual inspection for the oil. Air leaks in a unit of a low pressure cooler can be identified by pressurizing the cooler by heating the refrigerant so that it has a positive pressure.
ABSTRACT
This description generally relates to leak detection. This description relates more specifically to systems and methods for leak detection in a fluid compression system, where the fluid compression system is a heating, ventilation, air conditioning, and / or refrigeration (HVACR) system, which may include a cooler unit using a purge system.
A chiller unit can have two sides: a condenser side and an evaporator side. Both sides of the chiller unit can operate either individually or at high pressure and / or low pressure. A cooler unit may for example include a condenser side which operates at high pressure and an evaporator side which operates at low pressure. Due to the pressurization of the chiller unit, a leak may form on one or both sides of the chiller unit. A leak may be an air leak or a leak of working fluid emissions. The location of the leak on the cooler unit determines the effect of the leak on the cooler unit.
A leak associated with the evaporator can be an air leak, which can cause non-condensables to enter the cooler unit. A purge system can eliminate non-condensables to avoid deterioration and / or inefficiencies. A leak associated with the evaporator is typically not of concern due to the slow nature of the leak and the implementation of the purge system.
In addition, or alternatively, a leak may be associated with the condenser. A leak associated with the condenser may be a leakage of working fluid emissions, such as a refrigerant, outside the cooler unit. In some cases, a leak on the condenser can cause more damage than a leak on the evaporator due to the external leak. Refrigerant leaving the chiller unit via the leak on the condenser side can be detrimental to the environment and / or the operational requirements of the chiller's compliance.
In some embodiments, the condenser can operate at high pressure / positive pressure while the evaporator can operate at negative pressure / low pressure. The working fluid naturally moves from the high pressure areas to the low pressure areas. While air may leak into the evaporator which operates at low pressure, refrigerant may leak outside the cooler unit via a leak on the condenser which operates at high pressure. For example, a leak in the condenser may indicate that working fluid may be leaking out of the cooler unit.
Leakage of working fluid from a condenser is a concern due to environmental, safety and / or government regulations. For example, a leak detection in a fluid compression system which determines the particular location, the size of the leak and / or the rate of emission of working fluid would be beneficial to identify for example whether a leak may represent a threat and / or violate environmental, security, and / or government limitations.
As described herein, systems and methods for leak detection in a fluid compression system are described. In one embodiment, the systems and methods described herein can determine a leak size, for example on a low or high side of the cooler unit and estimate an emission rate associated with the leak size. The systems and methods described herein can provide a tangible approach and / or an objective way to describe leaks from the refrigerant emissions associated with a chiller unit. Leak detection can be performed annually or continuously, which can translate into cost savings when appropriate actions are taken in response to leak detection.
The present disclosure relates to a leak detection method comprising determining, during a vacuum period, a non-condensable purge exhaust flow rate from a purge system integrated into a cooler unit. The method includes determining a differential pressure, the differential pressure based on a pressure on the vacuum side of the cooler unit, where the pressure on the vacuum side comprises at least one of a pressure of one condenser and an evaporator pressure. The differential pressure is the pressure of the tank which is measured (for example the cooler unit where a particular tank thereof) in comparison to the pressure of the surrounding atmosphere (for example the outside of the cooler). The method includes calculating, via a controller, the purge exhaust flow rate and the differential pressure to identify a leak size based at least in part on the purge exhaust flow rate.
In some embodiments, the method includes determining an expected purge flow based on the purge exhaust flow for pressure on the vacuum side of a cooler circuit at the end of the vacuum period .
In some embodiments, a reduction in the purge exhaust flow indicates that the leak size is associated with pressure on the vacuum side of the cooler unit at the end of the vacuum period.
In some embodiments, the differential pressure includes a condenser differential pressure, an evaporator differential pressure, and a cooler unit differential pressure, each of which is referenced to the surrounding atmospheric pressure.
In some embodiments, the method includes determining a working fluid emission rate based at least in part on the leak size, the bleed exhaust rate, and the differential pressure, the working fluid emission rate being determined in real time.
In some embodiments, the method includes introducing cold fluid into respective piping connected to the condenser or the evaporator, the cold fluid serving to generate a period of complete vacuum and to cool the cooler unit.
In some embodiments, the purge system operates when the cooler unit is under complete vacuum, a state of operating vacuum, inactivity, or free cooling.
In certain embodiments, the method comprises displaying, via the control device, the purge exhaust flow rate, the differential pressure, and the leakage rate of non-condensables.
In some embodiments, the method includes automatically quantifying the purge rate and non-condensables and suppressing a manual leak check.
The present disclosure relates to a method for detecting leaks in a fluid compression system, comprising the operation of a purge system in a cooler unit, the purge system operating under vacuum;
monitoring an expected purge flow based on a purge exhaust flow;
detecting, via a pressure sensor on a high side and a low side of the cooler unit, a respective first pressure associated with a condenser and a respective second pressure associated with an evaporator;
determining a differential pressure based on the first and second respective pressures relative to an external pressure; and calculating a leak size based on the blowdown exhaust rate, differential pressure, and characteristics of non-condensable, wherein the leak size is on the top side of the unit. cooler.
In some embodiments, the expected purge flow relative to the purge exhaust flow and the differential pressure indicates the severity of the detected leak.
In some embodiments, the leak size on the top side of the cooler unit is a higher severity leak as compared to a detected leak on the bottom side of the cooler circuit, the top side of the cooler circuit being a condenser and the bottom side being an evaporator.
In some embodiments, the method includes determining a working fluid emission rate based on the leak size, the differential pressure, the characteristics of the working fluid, the purge efficiency, and the amount of purge.
In some embodiments, determining the purge exhaust rate is based in part on the amount of purge detected.
The present disclosure relates to a leak detection system comprising a purge system connected to a cooler circuit. The purge system operates under vacuum and includes a purge exhaust flow. The system includes a first pressure sensor associated with a condenser associated with the cooler circuit, a second pressure sensor associated with an evaporator associated with the cooler circuit, and a control device in electrical communication with the first and second pressure sensors which calculates a differential pressure compared to atmospheric pressure. The controller determines a condenser leak size based at least in part on the differential pressure. The controller calculates a working fluid emission rate based on the differential pressure and the condenser leak size.
In some embodiments, a decrease in the purge exhaust flow during vacuum removal and the creation of positive pressure indicates that working fluid is leaking from the cooler unit.
In some embodiments, the leak size is calculated for the evaporator, the condenser, and the cooler unit.
In certain embodiments, the refrigerant emissions due to a purge of the non-condensables are calculated on the basis of the purge exhaust flow rate and the purge efficiency.
In certain embodiments, the control device is configured to calculate a flow rate of emissions of working fluid for constituents at a positive pressure on the basis of a respective calculated leak size, characteristics of the working fluid, and differential pressure with respect to the atmosphere.
In some embodiments, the controller is configured to calculate a rate of emissions of working fluid for each of the cooler, evaporator, and condenser unit.
BRIEF DESCRIPTION OF THE DRAWINGS
Reference is now made to the drawings in which the reference numbers represent from one end to the other drawings of the corresponding parts.
Fig. 1 illustrates a perspective view of a fluid compression system according to one embodiment.
Fig. 2 illustrates a flow diagram of a leak detection in a fluid compression system according to one embodiment.
Fig. 3 illustrates a perspective view of a fluid compression system with a leak on the condenser side according to one embodiment.
Fig. 4 illustrates a flowchart for determining an emission rate in a fluid compression system according to one embodiment.
DETAILED DESCRIPTION
The working fluid leak inspection of a fluid compression system, such as a chiller unit as part of a heating, ventilation, air conditioning, and / or refrigeration (HVACR) system, can be traditionally performed by an electronic leak detection rod, a bubble test, or a visual inspection for oil.
A fluid compression system, such as an HVACR system which may include a chiller unit, may operate at pressures below atmospheric level (e.g. low pressure chiller unit) and may experience an accumulation non-condensable gases and / or other pollutants in the cooler unit. For example, when the cooler unit operates under vacuum, as referenced to the surrounding atmosphere, the cooler unit has a particular temperature and a negative pressure. For example, if a leak is present in the cooler unit, air and / or other non-condensables may enter the cooler unit due to the associated negative pressure, which can contribute to a accumulation of non-condensables.
A low pressure cooler unit may be a refrigeration system of the centrifugal cooler type in which one or both sides of the system operate under vacuum, while the condenser and / or the evaporator operate at a slightly negative pressure relative to the surrounding atmosphere. Leaks in a low pressure cooler unit that operates under vacuum can suck in atmospheric air, moisture, and / or other non-condensables.
For a low pressure chiller unit, leaks in a chiller unit can be identified by a first pressurization of the chiller unit by heating the working fluid of a unit, such as a refrigerant, so that it has positive pressure. Heating the working fluid can be a slow process, using either difficult-to-use temporary heaters and / or expensive unit-mounted heaters. In addition, once the chiller unit is pressurized, a full inspection can be a physically difficult and / or time consuming task.
In some cases, pressurized leak detection, as described above, can identify leak trajectories that incorrectly suggest maintenance repair since the leak detection test (s) cannot identify whether the leak is inside or outside the cooler unit.
Systems and methods for leak detection in a fluid compression system, such as a chiller unit as part of an HVACR system, using a purge system, are described herein. Leak detection can be performed via control and / or monitoring of a purge system for non-condensable infiltration, such as by leakage trajectories, while the cooler unit or particular sides thereof are under vacuum.
The accumulation of non-condensables can reduce the efficiency of the chiller unit. A purge system can generally be used to remove non-condensables (eg gas) which may accumulate in the cooler unit. The purge system for a chiller unit can remove air, moisture, and / or other non-condensables from the chiller unit by causing refrigerant vapors in the chiller unit to condense in a tank. purge. This results in a heat exchange relationship with another and second working fluid, such as for example another refrigerant used in a refrigeration circuit of the purge system. Refrigerant can be returned to the system, and the resulting non-condensables can then be removed from the chiller unit via an exhaust.
In some low pressure cooler units, the fluids can be of two different types: air leaking into the cooler unit or working fluid leaking out of the cooler unit. Leaks can occur, for example when air enters the low pressure side (for example evaporator) and / or when working fluid leaks from the high pressure side (for example condenser). Leaks can take the form of a combination of leak paths, such as leaks around a joint, physical entry, opening in the system, and / or a compromised area of the chiller unit. The combination of leak trajectories can be characterized as a leak orifice of a particular size (for example leak trajectories can be added to be characterized as an equivalent with respect to a leak size which is of the order of thousandths of an inch).
In some embodiments, air leaking into the chiller unit via a leakage path can result in approximately 1/10 ^th of refrigeration emissions when the noncondensables (e.g. air, etc.) are removed via a purge system in comparison to the same leak path in which a heat transfer fluid (for example refrigerant) leaks out of the cooler unit. While an air leak may not have a significant impact on the operation and / or significant emissions from the chiller unit, leaking working fluid outside the chiller unit may require '' be treated quickly to avoid deterioration and / or violation of environmental emission standards (for example the environmental protection agency (EPA), government agency, etc.). It would be beneficial to identify leakage paths which can result in comparatively low emissions (eg air leakage inside the cooler) and higher emission leakage paths (eg leaking working fluid outside the cooler unit).
As described here, leak detection in a fluid compression system can identify a leak size and an associated emission rate. A leak size is not necessarily a physical hole or orifice, but can be a number of leak paths, locations, openings, and / or entries into the system. Vacuum leak detection can be used to identify the location of a leak (eg evaporator or condenser) and / or quantify a leak size in a chiller unit. A working fluid (eg refrigerant) emission rate associated with the cooler can identify when a cooler unit has acceptable leak integrity and / or if leak repair is warranted.
Fig. 1 is a perspective view of a fluid compression system, according to one embodiment. The fluid compression system can be a cooler unit 10 as part of a heating, ventilation, air conditioning, and refrigeration (HVACR) system.
The cooler unit 10 comprises among other aspects, a compressor 18 connected by fluid circuit to a condenser 14, which is connected by fluid circuit to an expansion device (not shown), which is connected by fluid circuit to an evaporator 16 , and which is connected by fluid circuit to the compressor 18 in a cooling circuit. The cooler unit 10 may also include an economy device 22 which is fluidly connected to the compressor 18. The cooler unit 10 is exemplified and can be modified to include additional components. For example in one embodiment, the cooler unit 10 may include one or more flow control devices, a receiving container, a drying device, a liquid suction heat exchanger, or the like.
The cooler unit 10 can be provided with an amount of working fluid for use in the fluid compression system. In one embodiment, the working fluid used in the fluid compression system may be a heat transfer fluid, such as a refrigerant, which is in a heat exchange relationship with one or more processing fluids , such as water, but not limited thereto, for cooling or chilling water for other uses or applications, such as comfort cooling applications but not limited thereto. An original charge (e.g. amount of working fluid, refrigerant, etc.) can be supplied in the chiller unit 10 for cooling applications. The original charge is a finite amount of working fluid which can be supplied to the chiller unit 10 based on a particular capacity associated with the chiller unit 10.
A two-stage centrifugal compressor 18 is illustrated in Figure 1. It should be understood that the compressor 18 may alternatively be a single-stage centrifugal compressor, a three-stage centrifugal compressor, or another suitable multi-stage centrifugal compressor. The embodiments described may also be suitable for other types of compressors.
In one embodiment, a lubricant container assembly (not shown) can be included to manage the lubricant. In general, a lubricant drain from one or more carriers can be returned to the lubricant container assembly via one or more drain lines. A lubricant separator can be included in the lubricant container assembly to improve the separation of lubricant and working fluid so that the lubricant and working fluid can be reused in the cooler unit 10.
The cooler unit 10 can also include a control system 12 for controlling the operation of the cooler unit 10. The control system 12 can be a combination of hard drive and software but includes at least one hard drive. The control system 12 may include a display and / or identify the location of the detected leaks, as discussed again here.
The control system 12 may include a programmable control device 82 which includes, for example, a single integrated control unit. It will be appreciated that in other embodiments, the control unit 82 may include a distributed network of control elements (not shown). The number of control elements distributed in a given network can depend on the specific request of the principles described in this description. The control device 82 may include a processor, a memory, a clock and an input / output (I / O) interface (not shown). The control device 82 may include more or less additional components. The control device 82 can be configured to control a water temperature in order to obtain different operating adjustments (for example temperature, humidity, air quality, etc.) for comfort cooling applications.
As previously described, a low pressure cooler unit 10 can be a refrigeration system of the centrifugal cooler type which operates under a vacuum in the evaporator side 16 of the system, while the condenser 14 and / or the compressor 18 operate at a slightly pressure positive in relation to the surrounding atmosphere. In some embodiments, the cooler unit 10 can operate under vacuum in the condenser side 14 of the system, while the evaporator 16 operates at a slightly positive pressure relative to the surrounding atmosphere. Leaks in a low pressure cooler unit 10 that operates under vacuum can draw atmospheric air, moisture, and / or other non-condensables.
The cooler unit 10 can have multiple vacuum states. A vacuum state is when one or both of the sides of the cooler unit 10 are under vacuum. The plurality of vacuum states associated with the cooler unit 10 may include operation, inactivity, free cooling, or absence of vacuum. The cooler unit 10 can be switched from one vacuum state to another vacuum state. Although four void states are studied here, more or less void states can be associated with a chiller unit 10. The void states are discussed in detail below.
When the cooler unit 10 is in an operating vacuum state, the evaporator 16 may be under vacuum. When the evaporator 16 is under vacuum, the evaporator 16 can have a low pressure, low temperature, and / or a negative pressure relative to the surrounding atmosphere (for example external to the tank) while the condenser 14 can have high pressure, high temperature, and / or positive pressure relative to the surrounding atmosphere.
When the vacuum state of the cooler unit 10 is in operation, if a leak is present in the evaporator 16 (for example the low pressure side), non-condensables can enter the cooler unit 10. If a leak is present in the condenser 14 (for example the high pressure side), working fluid may leak from the system due to the positive pressure of the condenser 14 with respect to the surrounding system. In addition, or alternatively, if a leak is present on the evaporator 16 (for example on the low pressure side), air / non-condensables can leak into the system due to the negative pressure of the evaporator. 16 in relation to the surrounding atmosphere. The loss of refrigerant is ineffective for the chiller unit 10 and can be environmentally problematic.
When the vacuum state of the chiller unit 10 is inactive, the evaporator 16 and the condenser 14 can both be under complete vacuum. A complete vacuum is when both sides of the cooler unit 10 operate at negative pressure (eg negative inches of vacuum). In other words, the cooler unit 10 can be in negative pressure (e.g. low pressure) relative to the atmosphere outside the cooler unit 10 which can be positive pressure (e.g. high pressure) . Since particles move from high pressure to low pressure, air and / or non-condensables can move in the cooler unit 10.
When the vacuum state of the cooler unit 10 is free cooling, it is possible that the condenser 14 may be under vacuum. When the condenser 14 is under vacuum, the condenser 14 can present a low pressure, low temperature, and / or a negative pressure compared to the surrounding atmosphere, while the evaporator 16 can present a high pressure, high temperature, and / or a positive pressure in relation to the surrounding atmosphere. If a leak is present in the evaporator 16 (for example the high pressure side), working fluid may leak from the system due to the positive pressure of the evaporator 16 relative to the surrounding atmosphere. In addition, or alternatively, if a leak is present on the condenser 14 (for example on the low pressure side), air / non-condensables can leak from the system due to the negative pressure of the condenser 14 with respect to the positive pressure outside the condenser 14.
In one embodiment, the cooler unit 10 may have a vacuum-free state. That is, no side of the cooler unit 10 is under vacuum. When the cooler unit 10 is not vacuum (for example no vacuum is applied to any side), the cooler unit 10 may be in positive pressure. Both the evaporator 16 and the condenser 14 can have a positive pressure when they are not under vacuum. When the cooler unit 10 is not under vacuum, there may be no pressure difference in the cooler unit 10. The condenser 14 and the evaporator 16 can for example have the same pressures (for example equal). The cooler unit 10 can have a positive pressure (for example high pressure) while the surrounding / external atmosphere is at a negative pressure (low pressure).
When the cooler unit 10 has a vacuum-free state, the cooler unit 10 may include several pipes (not shown). The plurality of pipes can be used to introduce cold fluid into the heat exchanger (s) of the cooler unit 10 to cool the working fluid and create positive pressure. Cooled water can for example flow through the cooler evaporator 16 to cool the working fluid and result in a complete vacuum of the entire cooler unit 10 including the condenser 14, the compressor 18 and the evaporator 16 .
In one embodiment, a purge system 26 is connected to the condenser 14 in a cooler unit 10. The purge system 26 can remove atmospheric air and / or non-condensables. The purge system 26 separates the non-condensables from the working fluid (for example refrigerant). The non-condensables can be vented through an exhaust vent 28. In some embodiments, the purge system 26 can collect working fluid trapped in the purge system 26 by condensation refrigerant, thereby returning the working fluid to the system. All the remaining non-condensables, such as atmospheric air, can be vented via the exhaust vent 28.
The purge system 26 includes an amount of purge. The amount of bleed can be the amount of non-condensables, working fluid, other fluids (e.g. oil), or a combination thereof vented through the exhaust vent (e.g. 28 in the Figure 1). The amount of purge can be measured in pounds. The purge quantity can be measured by a sensor and / or a control device 82 associated with a purge system of the cooler unit 10.
The purge system 26 may include a purge exhaust flow (eg pounds / time) and a purge efficiency (eg pounds). The purge exhaust flow is the amount of non-condensables vented through the exhaust vent over a period of time. The purge efficiency is the pound (s) of working fluid lost per pound of exhaust non-condensables. The purge exhaust flow and purge efficiency can be used to calculate purge emissions. The working fluid purge emissions can be calculated by multiplying the exhaust flow of non-condensables by the purge efficiency. The purge quantity and / or the purge exhaust flow rate can be known and / or measured by a sensor and / or a control device 82 associated with the purge system 26.
The purge system 26 can be in any of the vacuum states of the cooler unit 10 described above. The purge system 26 can purge non-condensables in any of the vacuum states. The vacuum can operate under pounds per square inch of vacuum (PSIV). Operation of the purge system 26 under vacuum can provide calibrated measurements of purge exhaust flow rates.
When a leak occurs on a high pressure side of the cooler unit 10, the purge system 26 can experience a lowered amount of purge than when the leak is on a low pressure side. For example when a leak is found on the evaporator 16 whose operating pressure is lower than the surrounding atmospheric pressure (for example on the low pressure side of the cooler unit 10), it may result in non-condensables leaking in the cooler unit 10 and a higher purge quantity. In comparison, when a leak is found on the condenser 14 whose operating pressure is higher than the surrounding atmospheric pressure (for example high pressure side of the cooler unit 10), where a leak can result in the leakage of fluid working in the surrounding atmosphere, the purge system 26 may not have non-condensables to be expelled. In other words, when the evaporator 16 is under vacuum (for example low pressure) and the condenser 14 is not under vacuum (it presents for example a high pressure with respect to the surrounding atmosphere), the quantity of purge can be lowered in comparison to the case where the evaporator 16 and the condenser 14 are both under vacuum. The purge system 26 can purge more when both sides are under vacuum since the non-condensables leak in the cooler unit 10 in place of the leaking working fluid via a leak path on the high pressure side (for example the condenser 14) of the cooler unit 10.
The leak detection system further comprises several sensors 30-1, 30-2 for determining the pressure. The sensors 30-1, 30-2 are generally cited here as the plurality of sensors 30. One or more of the several sensors 30 can measure a pressure of the cooler unit 10 and / or for each side of the cooler unit cooler (for example condenser 14 and evaporator 16). In one embodiment, the plurality of sensors 30 can be several transducers.
The plurality of sensors 30 of the cooler unit 10 may include a first sensor 30-1 which is associated with the condenser 14 and a second sensor 30-2 which is associated with the evaporator 16. The first sensor 30-1 can measure a pressure associated with the condenser 14 of the cooler unit 10. The second sensor 30-2 can measure a pressure associated with the evaporator 16 of the cooler unit 10. The first pressure sensor 30-1 can for example measure a first pressure associated with the condenser 14, and / or the second pressure sensor 30-2 can measure a second pressure associated with the evaporator 16.
Although two sensors are described in Figure 1, more or less sensors for determining pressure can be included in one embodiment. In some embodiments, there may be more sensors (not shown) for measuring additional pressure. For example, a third sensor (not shown) can be arranged outside the cooler unit 10 to measure an external pressure outside the cooler unit 10.
In one embodiment, a differential pressure can be determined for a cooler unit 10. The differential pressure is the pressure of a tank of the cooler unit 10 in a vacuum state with respect to an external pressure. That is, the differential pressure is the pressure difference between the cooler unit 10, the condenser 14, and / or the evaporator 16 and the external ambient conditions. The ambient conditions are pressures external (for example external) to the cooler unit 10, such as for example atmospheric pressure.
In one embodiment, the differential pressure is the pressure of the vacuum tank which is measured (for example the cooler unit 10 as a whole which consists of the condenser 14 and the evaporator 16) compared to the pressure from the external atmosphere (for example from the outside of the tank). The one or more sensors 30 can measure a differential pressure on a respective top and bottom side of the cooler unit 10 in comparison to the pressure of the external atmosphere (for example outside the cooler unit 10 / tank) .
For an example, when the cooler unit 10 is in a vacuum state of inactivity, the cooler unit 10 is under complete vacuum, indicating that both the condenser 14 and the evaporator 16 are under vacuum . The differential pressure can be the pressure difference between the cooler unit 10 compared to the pressure outside the cooler unit 10. When both the condenser 14 and the evaporator are under vacuum, the first pressure (for example condenser 14) is measured by the first sensor 30-1 and the second pressure (for example evaporator 16) is measured by the second sensor 30-2. While these pressures can be equal in a vacuum state of inactivity, each side in comparison to the pressure of the external atmosphere (e.g. outside the cooler unit 10) can be used to calculate the differential pressure of l cooler unit 10.
In addition, or otherwise, when the cooler unit 10 has a vacuum-free state, the evaporator 16 may be in a positive pressure relative to the atmosphere and the condenser 14 may be in a positive pressure in relation to the atmosphere. When the cooler unit 10 has positive pressure (e.g. high pressure), refrigerant may leak out of the cooler unit 10 to external ambient conditions (e.g. positive pressure; high pressure), as discussed again here in figure 4.
The control system 12 (for example programmable control device etc.), as previously described, can be in electrical communication with the plurality of sensors 30 and calculates the differential pressure on the basis of pressures associated with the respective pressure sensors (for example 30-1, 30-2) and the surrounding atmosphere. The control system 12 can send signals to and receive signals from the chiller unit 10 for specific operations, such as the purge system 26.
As discussed further here, the leak detection systems and methods can determine a leak size, the location of the leak on the cooler unit 10, and / or calculate a working fluid emission rate (e.g. refrigerant example) of the cooler unit 10 based on the differential pressure, the purge exhaust flow rate of the purge system 26, and the characteristics of the non-condensables.
Fig. 2 illustrates a flow diagram for detecting a leak in a fluid compression system, according to one embodiment. Fig. 2 describes in particular a flow diagram of several vacuum states, including operation 32, inactivity 38, and free cooling 48, to determine a leak size.
A leak size can be determined in general for each of the evaporator, the condenser and the cooler unit as a whole based on the differential pressure, the purge exhaust flow and the characteristics of the non-condensables. . Once the leak size is determined for the entire cooler unit, a leak size can be assigned to one side of the cooler unit by comparing the leakage rate of non-condensables from the cooler unit under complete vacuum in case one but not both of the evaporator and the condenser is under vacuum.
The flowchart illustrated in Fig. 2 comprises a cooler unit 10. Aspects of the cooler unit 10 may be identical or similar to the aspects of the cooler unit 10 of FIG. 1. For the sake of simplicity of this description, the aspects previously described do not will not be described in more detail.
The cooler unit 10 may have two sides (for example the evaporator side and the condenser side, as previously discussed in Figure 1). Both sides of the chiller unit can operate independently and / or collectively under vacuum. The vacuum state of the cooler unit 10 can control whether the evaporator, the condenser, or both are under vacuum. To determine a leak size for a respective side of the cooler unit 10, the vacuum state of the cooler unit 10 can be inactivity 38, operation 32, or free cooling 48.
In order to determine a leak size associated with the condenser (for example 14 in FIG. 1), the cooler unit 10 can comprise first and second vacuum states, the first vacuum state being operation 32 and the second state of vacuum being inactivity 38. The cooler unit 10 can for example be in a first state of inactivity vacuum 38 and then in a second state of operating vacuum 32.
When there is operation 32, the cooler unit 10 may have the vacuum evaporator while a cooler unit 10 which is inactive 38 may have both the evaporator and the vacuum condenser. Using these two vacuum states (e.g. operation 32 and idle 38), the leak size can be assigned to the condenser of the cooler unit 10 by comparing the leakage rate of non-condensables from the cooler unit 10 under full vacuum at the leakage rate of non-condensables when the evaporator is under vacuum.
For Box 32, the vacuum state of the chiller unit 10 is operation. During operation 32, the evaporator (for example 16 in FIG. 1) operates under vacuum (for example negative pressure). When the cooler unit 10 is operating, the condenser (e.g. 14 in Figure 1) may not be under vacuum.
The vacuum difference can create different pressurized environments between the two sides of the chiller unit 10. The vacuum evaporator can create a low pressure environment (e.g. negative pressure) while the condenser can be a high pressure environment ( e.g. positive pressure) relative to the surrounding atmosphere. When there is operation 32, the evaporator and the condenser are no longer coupled; indicating that the evaporator and the condenser are no longer in the same vacuum. The evaporator is in negative pressure while the condenser is in positive pressure.
For Box 34, the evaporator vacuum and the purge exhaust flow can be measured. The pressure associated with the vacuum evaporator can be measured via one or more sensors (for example 30), as previously discussed in Figure 1. The vacuum of the evaporator can be measured by the pressure sensor or transducers to determine a pressure associated with the evaporator. Evaporator vacuum can be measured in units of pounds per square inch of vacuum (PSIV).
As previously described, the purge system can operate in any of the vacuum states and can remove non-condensables from the chiller unit 10. The purge system can include a quantity of purge and an exhaust flow rate purge. The amount of purge is the amount of non-condensables, working fluid, other fluids (e.g. oil), or a combination thereof vented from the purge system via the exhaust vent. The purge system may include a calculated purge emission rate (e.g., loss of working fluid; pounds / time) based on the purge exhaust rate measured as weighted by a purge efficiency and duration. In other words, the purge emissions (eg loss of working fluid from the purge) are the purge exhaust flow (eg pounds) of noncondensables vented (eg emitted) by the exhaust vent through the purge system weighted by the performance of particular purge emissions over a period of time.
For Box 36, when the chiller unit is running and the evaporator is under vacuum, a leak size associated with the evaporator can be calculated. The leak size is the combination of the leak paths that can be characterized in a manner that is similar to a particular leak size over a period of time. The leak size associated with the evaporator can be a permanent condition. The leak size associated with the evaporator can be calculated on the basis of the differential pressure, the drain exhaust flow rate, and the characteristics of the non-condensables. Each of these aspects can be known, and / or determined by a sensor and / or calculation. These aspects are discussed in detail as follows.
The differential pressure of the evaporator can be determined by one or more pressure sensors or transducers (for example 30 in Figure 1). A sensor (for example second sensor 30-2 in FIG. 1) can measure a pressure associated with the evaporator. The pressure of the evaporator can be compared to a pressure outside the chiller unit, such as the external atmosphere. Differential pressure is the difference between the two pressures. The differential pressure of the evaporator is for example the difference between the pressure associated with the evaporator (for example differential on the bottom side) and the pressure of the external atmosphere. The difference between the two pressures can be the differential pressure of the vacuum evaporator.
The purge exhaust rate is the amount of noncondensables vented from the purge system through the exhaust vent over a period of time (e.g. Box 34). The purge system may include purge factors. Purge factors can operate on a set of known factors, such as purge efficiency. The purge efficiency can indicate the amount of working fluid lost by the purge per pound of non-condensables removed from the cooling unit. The purge system is generally an efficient system. The purge amount may in some cases be 0.02 pounds of non-condensables per pound of air (eg, approximately 98% efficiency or better).
Characteristics of non-condensables can include density, viscosity, temperature, and volume, among others. The characteristics of non-condensables can quantify the resistance of non-condensables to flow. Viscosity is, for example, the measure of the internal fluid resistance of a substance, and higher viscosities indicate higher flow resistance while lower viscosities indicate lower flow resistance. The lower the viscosity, the higher the leakage or flow of non-condensables at a higher flow rate.
Evaporator differential pressure, purge exhaust flow, and non-condensable characteristics can be used to determine the evaporator leak size. The leak size can be calculated on the basis of the quantity of non-condensables eliminated by the purge system which operates at a particular efficiency when it is under a particular differential pressure of the evaporator. Since the evaporator leak size is the combination of the leak paths which can be characterized as a particular leak size for a period of time, the evaporator leak paths can be a calculated leak size. The evaporator leak size can be calculated and / or corresponds to a particular size leak orifice.
For box 38, the cooler unit 10 is in the idle vacuum state. When the cooler unit 10 is in the idle vacuum state, both the evaporator (e.g. 16 in Figure 1) and the condenser (e.g. 14 in Figure 1) are under vacuum and can be at the same pressure. The cooler unit 10 may overall have a negative pressure with respect to the surrounding atmosphere.
For Box 40, the vacuum of the cooler unit and the purge exhaust flow can be measured. The vacuum of the cooler unit 10 can be measured by one or more of the several pressure sensors or transducers (for example 30 in Figure 1). One or more sensors can measure a cooler unit pressure in pounds per square inch of vacuum (PSIV).
As previously discussed, the purge system can operate in any of the vacuum states and can remove non-condensables from the chiller unit 10. The purge system can include a quantity of purge and an exhaust flow rate purge. The purge quantity includes the pumped quantity of non-condensables, working fluid, other fluids (eg oil) or a combination thereof vented from the purge system via the exhaust vent. The purge system may include calculated purge emissions (eg, working fluid loss rate; pounds / time) based on the purge rate measured as weighted by purge efficiency and time. In other words, the purge emissions (eg loss of working fluid from the purge) are the purge exhaust flow (eg pounds) of non-condensables vented (eg emitted) by the exhaust vent through the purge system weighted by the particular purge efficiency over a period of time.
For Box 42, a leak size associated with the cooler unit 10 can be calculated based on the differential pressure, the purge exhaust flow, and the characteristics of the noncondensables. The leak size of the chiller unit is the combination of the leak paths which can be characterized in a manner which is similar to a particular leak size over a period of time. The leakage size of the chiller unit can be calculated based on the differential pressure of the chiller unit, the purge exhaust flow when the vacuum state of the chiller unit is inactive , and characteristics of non-condensables. The differential pressure and the purge exhaust flow rate can for example be measured by a sensor and / or calculated while the characteristics of the non-condensables can be known. Each of these aspects can be known and / or determined by a sensor and / or a calculation. These aspects are studied in detail as follows.
The differential pressure of the chiller unit is the difference between the pressure of the chiller unit and the pressure external to the chiller unit. When the vacuum state of the cooler unit 10 is inactive, the evaporator and the condenser can each exhibit pressure. In other words, each side of the cooler unit may have pressure. The pressure for each side (eg condenser, evaporator) of the chiller unit can be measured by a sensor (eg 30, transducers, etc.). That is, one of the plurality of sensors for each side of the cooler unit can measure a respective pressure. A first sensor (for example 30-1 in FIG. 1) can for example measure a pressure associated with the condenser while a second sensor (for example 30-2 in FIG. 1) can measure a pressure of the evaporator. When the chiller is inactive, the pressures can be equal. The pressure on each side of the cooler unit forms a pressure for the cooler unit 10 as a whole.
A pressure outside the cooler unit (e.g. external atmosphere) can be measured or can be considered to be constant. The pressure external to the chiller unit can be measured by another sensor. For example, a sensor can measure an ambient pressure outside the chiller unit.
The differential pressure of the chiller unit is the difference between the pressure of the chiller unit (eg condenser and evaporator pressure) and the pressure external to the chiller unit. As the chiller unit operates under vacuum, the differential pressure of the chiller unit may have negative pressure (e.g. low pressure).
The purge exhaust flow is the amount of noncondensables vented from the purge system through the exhaust vent over a period of time. The purge system may include purge factors. Purge factors can operate on a set of known factors, such as purge efficiency. The purge efficiency can indicate the amount of working fluid lost by the purge per pound of non-condensables removed from the chiller unit. The purge system is generally an efficient system. The purge amount can be, in some cases, 0.02 pounds of non-condensables per pound of air (eg, approximately 98% efficiency or better).
Characteristics of non-condensables can include density, viscosity, temperature, and volume. The characteristics of the non-condensables can be known, for example on the basis of the type of atmospheric constituents, their temperature, pressure, and / or external factors. The characteristics of non-condensables can quantify the resistance of non-condensables to flow. Viscosity is, for example, a measure of the resistance to the internal fluid of a substance, and higher viscosities indicate greater resistance to flow while low viscosities indicate less resistance to flow. The lower the viscosity, the greater the leakage or flow of non-condensables at a higher flow rate.
The differential pressure of the chiller unit, the purge exhaust flow when the vacuum state of the chiller unit is inactive, and the characteristics of non-condensables, can be used to determine the size of leakage from cooler unit. In one embodiment, the non-condensables can be removed by the purge system which operates at a particular efficiency when it is under a particular differential pressure of the cooler unit. Since the cooler unit leak size is a combination of leak paths that can be characterized as a particular leak size over a period of time, the cool unit leak paths can be a calculated leak size .
The non-condensables can be eliminated by the purge system operating at a particular exhaust flow rate when it is under a particular differential pressure when the cooler unit is inactive. The leak inside the evaporator can be for example 0.7 pounds while the purge system purges 0.5 pounds of noncondensables. There is a difference of 0.2 pounds between the leak in cooler unit 10 and the purge efficiency. Based on the difference, an amount of working fluid lost to the purge can be determined to be 0.2 pounds. That is, the expected purge exhaust rate may be 0.7 pounds, but the amount of purge is 0.5 pounds. The difference of 0.2 pounds is the purge yield (eg working fluid lost in the purge).
For Box 44, we can calculate a condenser leak size. The condenser leak size can be calculated by subtracting the evaporator leak size (e.g. box 36) from the cooler unit leak size (e.g. box 42). Since the chiller unit has two sides, a condenser side and an evaporator side, the difference between the chiller unit leak size and the evaporator leak size can provide the leak size associated with the condenser. For example, the evaporator leak size can be subtracted from the cooler unit leak size to determine the condenser leak size. In other words, the condenser leak size is equal to the cooler unit leak size minus the evaporator leak size.
In Box 46, a work fluid emission rate can be calculated for a chiller unit. The working fluid emission rate is based on a respective leak size, a respective differential pressure, and characteristics of the working fluid, as discussed further in Figure 4.
As previously mentioned, once the leak size is determined for the cooler unit and one side of the cooler unit, a leak size can be assigned to the other side of the cooler unit by comparing the leakage rate of the non-condensables from the complete vacuum cooler unit in case one but not both, of the evaporator and the condenser is in vacuum. In some embodiments, it may be beneficial to determine an evaporator leak size when the vacuum state of the cooler unit 10 does not evacuate the evaporator (e.g. operation).
To determine a leak size associated with the evaporator, the vacuum state of the cooler unit 10 may include a free cooling vacuum state and an idle vacuum state. When the chiller unit 10 is in the free cooling vacuum state, the chiller unit 10 can present the condenser under vacuum while a chiller unit 10 which is inactive can present both the evaporator and the vacuum condenser. Using these two vacuum states (e.g. free cooling and idle), a leak size can be assigned to the evaporator of the cooler unit 10 by comparing the leakage rate of non-condensables from the cooler unit 10 under complete vacuum (for example inactivity) in case the condenser is under vacuum (for example operation).
In Box 48, the vacuum state of the cooler unit 10 is free cooling. When the cooler unit is in the free cooling vacuum state 48, the condenser (e.g. 14 in Figure 1) operates under vacuum (e.g. negative pressure). When the chiller unit 10 is in the free cooling vacuum state, the evaporator (for example 16 in Figure 1) may not be in vacuum.
The vacuum difference can create different pressurized environments between the two sides of the chiller unit 10. The vacuum condenser can create a low pressure environment while the evaporator can be a high pressure environment (e.g. positive pressure) by in relation to the surrounding atmosphere. When the vacuum state of the chiller unit is free cooling 48, the evaporator and the condenser are no longer coupled, indicating that the evaporator and the condenser are no longer both in the same vacuum. The condenser is in negative pressure while the evaporator is in positive pressure.
For Box 50, the condenser vacuum and the purge exhaust flow can be measured. The pressure associated with the vacuum condenser can be measured via one or more of the several sensors (for example 30), as previously discussed in Figure 1. The vacuum of the condenser can be measured by the pressure sensor or transducers to determine a pressure associated with the evaporator. The condenser vacuum can be measured in units of pounds per square inch of vacuum (PSIV).
As previously described here, the purge exhaust flow is the amount of non-condensables vented through the exhaust vent (for example 28 in Figure 1). The purge exhaust flow can be measured by a sensor and / or a control device (for example 82 in FIG. 1) associated with a purge system of the cooler unit 10. As previously described in FIG. 1 , the purge system (eg 26 in Figure 1) can operate in any of the vacuum states and can eliminate noncondensables from the chiller unit 10. A purge exhaust flow (eg book / time) is the amount of purge (eg pounds) of non-condensables vented (eg emitted) through the exhaust vent by the purge system at a particular efficiency in a period of time.
For Box 52, when the cooler unit is in the free cooling vacuum state, the condenser is under vacuum, and a leak size associated with the condenser can be calculated. The leak size is the combination of the leak paths that can be characterized in a manner that is similar to a particular leak size for a period of time. The leak size associated with the condenser can be calculated on the basis of the differential pressure, the drain exhaust flow rate, and the characteristics of the non-condensables. The differential pressure and the purge exhaust flow rate can for example be measured by a sensor and / or calculated while the characteristics of the non-condensables can be known. Each of these aspects can be determined by a sensor and / or calculation. These aspects are studied in detail as follows.
The differential pressure of the condenser can be determined by one or more of the several pressure sensors or transducers (for example 30 in Figure 1). A sensor (for example second sensor 30-1 in FIG. 1) can measure a pressure associated with the condenser. The pressure of the condenser can be compared to a pressure outside the chiller unit, such as the external atmosphere. Differential pressure is the difference between the two pressures. The differential pressure of the condenser is for example the difference between the pressure associated with the condenser (for example differential on the bottom side) and the pressure of the external atmosphere. The difference between the two pressures can be the differential pressure of the vacuum condenser.
The purge exhaust flow is the amount of noncondensables vented from the purge system through the exhaust vent over a period of time (for example, box 34). The purge system may include purge factors. Purge factors can operate on a set of known factors, such as purge efficiency. The purge efficiency can indicate the amount of working fluid lost by the purge per pound of non-condensables removed from the chiller unit. The purge system is generally an efficient system. The purge amount may in some cases be 0.02 pounds of non-condensables per pound of air (eg, approximately 98% efficiency or better).
Characteristics of non-condensables can include density, viscosity, temperature, and volume. The characteristics of the non-condensables can be known for example on the basis of the type of atmospheric constituents, their temperature, pressure, and / or external factors. The characteristics of non-condensables can quantify the resistance to flow of non-condensables. Viscosity is, for example, the measure of the resistance to the internal fluid of a substance, and high viscosities indicate high resistance to flow while low viscosities indicate less resistance to flow. The lower the viscosity, the greater the leakage or flow of non-condensables at a higher flow rate.
The condenser differential pressure, the purge exhaust flow, and the characteristics of the non-condensables can be used to determine the condenser leak size. In one embodiment, the non-condensables can be eliminated by the purge system which operates at a particular efficiency when it is under a particular differential pressure of the condenser. Since the condenser leak size is the combination of the leak paths which can be characterized as a particular leak size for a period of time, the condenser leak paths can be a calculated leak size. The condenser leak size can be calculated and / or corresponds to a particular leak size.
As previously described here, a leak size associated with the cooler unit 10 can be calculated when the vacuum state of the cooler unit is inactive 38. The leak size of the cooler unit can be based on the differential pressure, purge quantity, and characteristics of the non-condensables in box 42. To simplify this description, the state of inactivity vacuum in box 38, the measurement of the cooler unit in Box 40, and the calculation of the leakage size of the cooler unit in Box 42, as previously described, will not be described in more detail.
In one embodiment, the cooler unit leak size (e.g. box 42) and the condenser leak size (e.g. box 52) can be used to calculate an evaporator leak size.
For Box 54, an evaporator leak size can be calculated. The evaporator leak size can be calculated by subtracting the condenser leak size (e.g. box 52) from the cooler unit leak size (e.g. box 42). Since the chiller unit consists of two sides, a condenser side and an evaporator side, the difference between the leak size of the cooler unit and the leak size of the condenser can provide a leak size associated with the evaporator. For example, the evaporator leak size can be subtracted from the cooler unit leak size to determine an evaporator leak size. In other words, the evaporator leak size is equal to the cooler unit leak size minus the condenser leak size.
For Box 56, an emission rate can be calculated for a chiller unit. The emission rate can be a working fluid emission rate. The working fluid emission rate is based on a respective leak size, a respective differential pressure, and the characteristics of the working fluid, as further discussed in Figure 4. As discussed in Figure 4, a flow rate d emissions for a chiller unit can be determined from the leak size associated with the chiller unit, the evaporator and the condenser.
Fig. 3 illustrates a perspective view of a fluid compression system with a leak on the condenser side, according to one embodiment. Aspects of the fluid compression system are identical or similar to the aspects of the chiller unit 10 of Figure 1. In order to simplify this description, the previously described aspects will not be described in more detail.
In one embodiment, the cooler unit 10 is a low pressure vacuum cooler unit. The vacuum state of the cooler unit 10 may be the operation. When the cooler unit 10 is in operation, the evaporator 16 is under vacuum while the condenser 14 is not under vacuum. The cooler unit 10 can comprise operations on the high pressure side H (for example pressure above atmospheric pressure) and on the low pressure side L (for example pressure below atmospheric pressure). The cooler unit 10 can for example present the evaporator 16 under vacuum (for example low pressure) and the condenser 14 in a positive pressure (for example high pressure).
A purge amount and a non-condensable purge exhaust flow rate can be determined for a chiller unit 10, as previously described. The purge exhaust flow can be used to define an expected purge flow. The expected purge rate is a prediction of an amount of non-condensables which are to be removed from the chiller unit 10 by the purge system 26 over a period of time.
The expected purge flow can be used to determine if a leak 20 is present on the condenser 14 of the chiller unit 10. A variation of the purge exhaust flow from the expected purge flow can for example indicate a new leak and / or leak 20. That is to say an actual quantity compared to an expected quantity. As the working fluid and / or air travels through the cooler unit 10 under high pressure (e.g. operation) in the condenser 14 and the compressor 18, the purge exhaust flow can be measured and compared to the expected purge flow when the condenser 14 and the compressor 18 are under vacuum / low pressure (for example inactivity). A reduction in the purge exhaust flow compared to the expected purge flow can presume that a leak 20 is on the condenser side 14 (for example the high pressure H) of the cooler unit 10.
The expected purge flow can be used to determine whether the non-condensables remain in the cooler unit 10 or escape without being purged by the purge system 26. For example if the quantity of non-condensables purged from the purge 26 is less than the expected purge flow, a leak 20 may be the emission of refrigerant and / or air outside the cooler unit 10. Like the working fluid and / or the air are released from leak 20 and not through the purge system in the cooler unit 10, the purge exhaust flow may decrease.
When the expected purge flow rate decreases (for example reduction), it can be assumed that a leak 20 associated with the condenser 14 of the cooler unit 10 may be present. In other words, when the expected purge flow rate decreases, it is assumed that the condenser 14 operating under high pressure may exhibit the leakage 20 which is the expulsion of refrigerant and / or of air external to the cooler unit 10 Alternatively, when the expected purge flow does not decrease (for example is not modified), it can be assumed that the leak (for example 20) is not in the condenser 14 but that there is a leak in evaporator 16 (for example under acceptable conditions).
Although the cooler unit 10 of Figure 3 illustrates an evaporator 16 in a low pressure L and a condenser in a high pressure H, the pressures associated with each side of the cooler unit 10 may vary in embodiments different. In some examples, such as when the vacuum state of the cooler unit 10 is free cooling, the pressures associated with the sides of the cooler unit 10 can be switched (e.g. condenser 14 in low pressure, evaporator 16 in high pressure). In such a scenario, a leak can be attributed to the side of the cooler unit 10 which is not vacuum (eg evaporator 16).
The leak 20 may have a flow rate of emissions of working fluid (for example refrigerant). The working fluid emission rate is the amount of working fluid (eg refrigerant) which leaks out of the cooler unit 10 via the leakage 20. The working fluid emission rate can be determined based on a leak size, differential pressure, and the characteristics of the working fluid, as discussed again here in Figure 4.
Fig. 4 illustrates a flow diagram determining an emission rate in a fluid compression system, according to one embodiment. Fig. 4 describes in particular cooler unit states, comprising inactivity 58, operation 62, free cooling 70, and positive pressure 78 (for example absence of vacuum), and an associated emission rate.
In one embodiment, the emission rate can be the amount of refrigerant lost by a leak as well as the refrigerant that is emitted by the purge system. The working fluid emission rate can be calculated in pounds per unit of time (eg pounds per day).
For Box 10, a cooler unit 10 has two sides: an evaporator and a condenser. The aspects of the cooler unit 10 may be the same or similar to the aspects of the cooler unit 10 of Figure 1. The cooler unit 10 may have more than one cooler unit state. Each of the several cooler unit states can include one of the several vacuum states, as previously described. For example, each of the several cooler unit states can include a different vacuum state: inactivity, operation, free cooling, and absence of vacuum (represented as positive pressure). The cooler unit states may have vacuum states of the cooler unit 10 in which both the condenser and the vacuum evaporator (e.g. idle vacuum state), or one of the condenser or the evaporator, but not both, are under vacuum (for example operating vacuum or free cooling states), or neither the evaporator and the condenser are under vacuum (for example no vacuum state or " positive pressure ”).
As illustrated in Figure 4, an emission rate for the chiller unit 10 can be determined for each chiller unit state. The emission rate can be a working fluid emission rate. The working fluid emission rate is the amount of working fluid (e.g. refrigerant) that leaks out of the cooler unit 10 from a leak over time. In one embodiment, the working fluid emission rate can be determined based on a leak size, a differential pressure, and the working fluid characteristics.
For Box 10, a cooler unit can include multiple cooler unit states (e.g. 58, 62, 70, and 78). The aspects of the cooler unit 10 may be identical or similar to the aspects of the cooler unit 10 of Figure 1. In order to simplify this description, the previously described aspects will not be described in more detail.
For Box 58, the chiller unit state is inactivity. The idle cooler unit state may include an idle vacuum state. The idle vacuum state is when both the evaporator and the condenser are in full vacuum. Full vacuum can be when both sides of the chiller unit are in the same vacuum. In some embodiments, although the condenser and the evaporator are in the same vacuum, the two may not be at the same pressure. For example while it is under full vacuum, the condenser may have a slightly higher pressure compared to the evaporator which may have a slightly lower pressure. Overall, during a period of complete vacuum, the chiller unit is in negative pressure.
For Box 60, the chiller unit emission rate can be calculated. Fluids will generally flow from positive to negative pressure. As the chiller unit 10 has an overall negative pressure with respect to the surrounding atmosphere which is positive (eg high pressure), the working fluid cannot leak from the chiller unit 10. A leak in the negative pressure cooler unit may instead have non-condensables entering the cooler unit. Non-condensables can displace working fluid in the chiller unit, which can lower the chiller unit efficiency. Since the working fluid does not leak from the condenser, the working fluid emission rate is equal to the amount of purge and the purge efficiency.
When the chiller unit state is inactive, which includes an inactive vacuum state, the emission rate is based on a purge amount and a purge efficiency of the purge system. Non-condensables entering the cooler unit can be purged through the purge system through the exhaust vent. The amount of purge includes the amount of non-condensables, working fluid, other fluids (e.g. oil), or a combination thereof eliminated by the purge system. The purge system includes a purge efficiency. The purge efficiency may indicate the amount of working fluid lost during the purge compared to the amount of non-condensables removed from the cooler unit during the purge. As previously mentioned, the purge system is generally an efficient system. The purge amount can be, in some cases, 0.02 pounds of non-condensables per pound of air (eg, approximately 98% efficiency or better). The amount of non-condensables purged and the purge efficiency are equal to the chiller unit emission rate when the chiller unit is inactive.
For Box 62, the chiller unit state is operation. The operating cooler unit state includes an operating vacuum state. When the condition of the chiller unit is operating, the evaporator is under vacuum, while the condenser is in a positive pressure with respect to the atmosphere. As the condenser is in positive pressure, working fluid can leak out of the cooler unit 10.
For Box 64, one can calculate the flow rate of condenser working fluid emissions. The condenser working fluid emission rate can be calculated based on a leak size, differential pressure, and the characteristics of the working fluid. These factors can determine how much working fluid escapes through the leak associated with the condenser under a particular pressure, as discussed in detail below.
The condenser leak size is the "size" of the condenser leak. The condenser leak size can be assigned based on the difference in purge amount when a vacuum state of the chiller unit is inactive and then the operation. As previously described in Box 44 in Figure 2, the condenser leak size can be calculated from the cooler unit leak size and the evaporator leak size. The condenser leak size is equal to the cooler unit leak size minus the evaporator leak size, thereby providing the condenser leak size.
The condenser pressure can be determined by one or more of the pressure sensors or transducers (e.g. 30 in Figure 1). A sensor (for example second sensor 30-1 in FIG. 1) can measure a pressure associated with the condenser. The pressure of the condenser can be compared to a pressure outside the chiller unit, such as the external atmosphere. Differential pressure is the difference between the two pressures. The differential pressure of the condenser is for example the difference between the pressure of the condenser and the pressure of the external atmosphere. The difference between the two pressures is the differential pressure of the condenser.
The characteristics of the working fluid may be the type of refrigerant, the pressures associated with the type of refrigerant, temperature, molecular weight, viscosity, and density, among other characteristics. The characteristics of the working fluid can quantify flow resistance and performance. For example, the type of refrigerant can operate in a particular way at a particular temperature or pressure. In addition, viscosity is a measure of the internal fluid resistance of a substance, and higher viscosities indicate higher resistance to flow while low viscosities indicate less resistance to flow. A lower viscosity indicates a higher leakage or flow of the working fluid at a higher flow rate.
The condenser working fluid emission rate relates to the condenser side of the chiller unit. The condenser working fluid emission rate is based on the condenser leak size, condenser differential pressure, and the characteristics of the working fluid. These factors can be used to calculate an amount of working fluid under a particular amount of pressure that can escape from a particular size leak associated with the condenser.
For Box 66, the flow rate of evaporator working fluid emissions can be calculated. As the evaporator is under vacuum (e.g. negative pressure), non-condensables can leak into the cooler unit on the evaporator side. The evaporator working fluid emission rate may not be dependent on the differential pressure of the evaporator. In addition, due to pressure differences, the condenser and the evaporator are no longer coupled, indicating that the evaporator and the condenser are no longer both in the same vacuum. The evaporator working fluid emission rate can be calculated based on a purge amount and the purge efficiency of the purge system.
As previously described here, the non-condensables entering the cooler unit can be purged by the purge system by the exhaust vent. The amount of purge includes the amount of non-condensables, working fluid, other fluids (e.g. oil), or a combination thereof eliminated by the purge system. The purge system includes a purge efficiency. The purge efficiency may indicate the amount of working fluid lost during the purge compared to the amount of non-condensables removed from the cooler unit during the purge. The quantity of non-condensables purged and the purge yield can be measured by a sensor and / or the control device, as previously described. The purge yield is the amount of working fluid lost by the purge, which may be the pounds of working fluid lost per pound of noncondensables that have escaped.
For Box 68, the flow rate of working fluid emissions from the chiller unit can be calculated. The working fluid emission rate is the amount of refrigerant lost by a leak. The coolant unit working fluid emission rate is therefore based on the sum of the condenser working fluid emission rate and the evaporator working fluid emission rate. The chiller unit emission rate is the amount of working fluid expelled from the condenser leak and the amount of working fluid emissions from the purge system, the sum of which is equal to the amount working fluid exiting the cooler unit in one form or another.
The working fluid emission rate for a respective component can be calculated as a percentage. The working fluid emission rate may be a percentage of refrigerant emissions leaving the chiller unit. The working fluid emission rate can be useful when determining whether a particular chiller unit 10 is operating efficiently and / or within the standards of the Environmental Protection Agency (EPA) and / or other environmental standards.
For Box 70, the chiller unit state is free cooling. The free cooling chiller unit state includes a free cooling vacuum state. When the chiller unit is in the free cooling vacuum state, the condenser is in vacuum while the evaporator is in positive pressure, relative to the atmosphere. Although this scenario may take place, it generally appears less often than when the evaporator is under vacuum and the condenser is in positive pressure (for example, cooling unit operating state, box 62).
For Box 72, the evaporator working fluid emissions can be calculated. The working fluid emission rate associated with the evaporator can be based on the evaporator leak size, the evaporator differential pressure, and the characteristics of the working fluid. That is, the rate of emission of working fluid depends on the pressure and characteristics of the working fluid which can move by the size of the leak over a period of time.
These factors can determine how much working fluid escapes through the leak associated with the evaporator under a particular pressure, as discussed in detail below.
The evaporator leak size is the "size" of the evaporator leak. The evaporator leak size can be assigned based on the difference in purge amount when a vacuum state of the cooler unit is idle and free cooling. As described above in Box 54 in Figure 2, the evaporator leak size can be calculated from the cooler unit leak size and the condenser leak size. The evaporator leak size is equal to the cooler unit leak size minus the condenser leak size, thereby providing the evaporator leak size.
The pressure of the evaporator can be determined by one or more of the pressure sensors or transducers (for example 30 in Figure 1). A sensor (for example second sensor 30-2 in FIG. 1) can measure a pressure associated with the evaporator. The pressure of the evaporator can be compared to a pressure outside the chiller unit, such as the external atmosphere. Differential pressure is the difference between the two pressures. For example, the differential pressure of the evaporator is the difference between the pressure of the evaporator and the pressure of the external atmosphere. The difference between the two pressures is the differential pressure of the evaporator.
The characteristics of the working fluid may be the type of refrigerant, the pressures associated with the type of refrigerant, temperature, molecular weight, viscosity, and density, among other characteristics. The characteristics of the working fluid can quantify flow resistance and performance. The type of refrigerant can for example operate in a particular way at a particular temperature or pressure. In addition, viscosity is a measure of the internal fluid resistance of a substance, and higher viscosities indicate higher resistance to flow while low viscosities indicate less resistance to flow. The lower the viscosity, the higher the leakage or flow of the working fluid at a higher flow rate.
The evaporator working fluid emission rate relates to the evaporator side of the chiller unit. The evaporator working fluid emission rate is based on the evaporator leak size, the evaporator pressure differential, and the characteristics of the working fluid. These factors can be used to calculate an amount of working fluid under a particular amount of pressure that can escape from a leak of a particular size associated with the evaporator.
For Box 74, one can calculate a flow rate of condenser working fluid emissions. As the condenser is under vacuum (eg negative pressure), non-condensables may leak into the cooler unit on the condenser side. The condenser working fluid emission rate may not depend on the condenser differential pressure. In addition, due to pressure differences, the evaporator and the condenser are no longer coupled, indicating that the evaporator and the condenser are no longer in the same vacuum. The condenser working fluid emission rate is based on a purge amount and a purge efficiency of the purge system.
As described above, non-condensables entering the chiller unit can be purged by the purge system through the exhaust vent. The amount of purge includes the amount of non-condensables, working fluid, other fluids (e.g. oil), or a combination thereof eliminated by the purge system. The purge system includes the purge efficiency. The purge efficiency may indicate the amount of working fluid lost during the purge compared to the amount of non-condensables removed from the cooler unit during the purge. The quantity of non-condensables purged and the purge yield can be measured by a sensor and / or the control device, as previously described.
For Box 76, a flow rate of working fluid emissions from the chiller unit can be calculated. The coolant unit working fluid emission rate is based on the sum of the evaporator and condenser emissions.
For Box 78, the condition of the chiller unit is positive pressure. A state of the positive pressure cooler unit includes a state of no vacuum. When the cooler unit has no vacuum, the cooler unit is in positive pressure (e.g. high pressure) while spaces outside the cooler unit are negative (e.g. low pressure). The differential pressure when no vacuum is present can be a pressure measured relative to a reference pressure. A pressure outside the cooler unit, such as an ambient pressure, can for example be a reference pressure. Differential pressure can be a difference between vacuum pressure and atmospheric pressure, measured in pounds per square inch differential (PSID).
For Box 80, the flow rate of working fluid emissions for the evaporator and the condenser can be calculated. Since the cooler unit is in positive pressure, the two sides of the cooler unit are weighted in the calculation of the working fluid emission rate. Evaporator and condenser working fluid emission rates are based on the last known total cooler unit leak size, average differential pressure associated with the cooler unit, and fluid characteristics of work.
The last known cooler leak size can be calculated based on the cooler unit leak size, the cooler unit differential pressure, the bleed exhaust rate, and the characteristics of the non condensable, as previously described here in box 42 in FIG. 2. In order to simplify this description, aspects previously described will not be described in more detail.
The differential pressure of the chiller unit can be measured by one or more of the sensors (for example 30), as previously described in figure 1. The average differential pressure can be calculated by the control device on the basis of historical differential pressures associated with the chiller unit. Historical differential pressures can be averaged to result in an average chiller unit pressure differential.
In addition, the characteristics of the working fluid can be based on the type of refrigerant, the pressures associated with the type of refrigerant, temperature, molecular weight, viscosity, and density, among other characteristics, as discussed above. above.
The cooler unit leakage size, the average cooler unit differential pressure, and the working fluid characteristics can be calculated to determine a working fluid emission rate for the evaporator and condenser. .
The detection of leaks in a chiller unit can provide information regarding the flow rate of working fluid emissions (eg, refrigerant emission) outside the chiller unit. By determining a location, a leak size, and calculating a working fluid emission rate, a user can know if the chiller unit is in compliance with the state and / or federal emission guidelines refrigerant. Leak detection in the chiller unit can also identify urgent leaks (condenser leak), which can be resolved appropriately and save money by repairing them on time. The systems and methods described herein can provide information relative to the size of the leak orifice and the associated emission rate of a chiller unit, thereby indicating compliance or non-compliance with standards. regulation.
The terminology used in this description intends to describe particular embodiments and is not intended to be limiting. The terms "a", "an", and "the", "la" also include plural forms unless otherwise clearly indicated. The terms "includes" and / or "comprising", when used in this description, specify the presence of the aspects, whole numbers, steps, operations, elements and / or constituents mentioned but do not exclude the presence or the addition of one or more other aspects, whole numbers, steps, operations, elements, and / or constituents.
Compared to the previous description, it should be understood that modifications can be made in detail, without departing from the scope of the invention of the patent. The description and the embodiments described are to be regarded only as examples, with a real field and spirit of the invention being indicated by the broad significance of the claims.

权利要求:
Claims (20)
[1" id="c-fr-0001]
1. Leak detection method, characterized in that it comprises:
determining, during a vacuum period, a non-condensate purge exhaust flow rate from a purge system (26) integrated with a cooler unit (10);
determining a differential pressure, the differential pressure based on a pressure on the vacuum side of the cooler unit (10), wherein the pressure on the vacuum side comprises at least one of a pressure of a condenser ( 14) and a pressure of an evaporator (16); and calculating, via a control device (82), the purge exhaust flow and the differential pressure to identify a leak size based at least in part on the purge exhaust flow.
[2" id="c-fr-0002]
2. Method according to ia claim 1, characterized in that it further comprises determining an expected purge flow based on the purge exhaust flow for a pressure on the vacuum side of a circuit of the cooler during from the end of the vacuum period.
[3" id="c-fr-0003]
3. Method according to claim 1, characterized in that a reduction in the purge exhaust flow indicates that the leak size is associated with a pressure on the vacuum side of the cooler unit (10) at the end of the vacuum period.
[4" id="c-fr-0004]
4. Method according to claim 1, characterized in that the differential pressure comprises a condenser differential pressure (14), an evaporator differential pressure (16), and a cooler unit differential pressure (10), each of which is in reference to the surrounding atmospheric pressure.
[5" id="c-fr-0005]
The method of claim 1, further comprising determining a flow rate of working fluid emissions based at least in part on the leak size, the bleed exhaust flow rate, and the differential pressure. , the working fluid emission rate being determined in real time.
[6" id="c-fr-0006]
6. The method of claim 1, further comprising introducing cold fluid into a respective pipe connected to the condenser (14) or the evaporator (16), the cold fluid serving to generate a period of complete vacuum and to cool the cooler unit (10).
[7" id="c-fr-0007]
7. Method according to claim 1, characterized in that the purge system operates when the cooler unit (10) is under complete vacuum, a state of operating vacuum, inactivity, or free cooling.
[8" id="c-fr-0008]
8. Method according to claim 1, characterized in that it further comprises the display, via the control device (82), of the purge exhaust flow, of the differential pressure, and of the no leakage flow. -condensable.
[9" id="c-fr-0009]
9. Method according to claim 1, characterized in that it further comprises the automatic quantification of the purge flow rate and of the non-condensables and the elimination of a manual leak check.
[10" id="c-fr-0010]
10. Method for detecting leaks in a fluid compression system, characterized in that it comprises:
operating a purge system in a cooler unit (10), the purge system operating under vacuum;
monitoring an expected purge flow based on a purge exhaust flow;
the detection, via a pressure sensor (30-1, 30-2) on a high side and a low side of the cooler unit (10), of a first respective pressure associated with a condenser (14) and d 'a second respective pressure associated with an evaporator (16);
determining a differential pressure based on the first and second respective pressures relative to an external pressure; and calculating a leak size based on the blowdown exhaust rate, differential pressure, and characteristics of non-condensable, wherein the leak size is on the top side of the unit. cooler (10).
[11" id="c-fr-0011]
11. Method according to claim 10, characterized in that the expected purge flow rate relating to the purge exhaust flow rate and the differential pressure indicates the severity of the detected leak.
[12" id="c-fr-0012]
12. Method according to claim 10, characterized in that the leak size on the top side of the cooler unit (10) is a leak of higher severity as compared to a leak detected on the bottom side of the cooler circuit. (10), the top side of the cooler circuit being a condenser (14) and the bottom side being an evaporator (16).
[13" id="c-fr-0013]
13. The method of claim 10, characterized in that it further comprises determining a rate of emission of working fluid on the basis of the leak size, the differential pressure, the characteristics of the working fluid , purge yield, and amount of purge.
[14" id="c-fr-0014]
14. Method according to claim 10, characterized in that the determination of the purge exhaust flow rate is based in part on the quantity of purge detected.
[15" id="c-fr-0015]
15. Leak detection system, characterized in that it comprises:
a purge system connected to a cooler circuit (10), the purge system operating under vacuum and including a purge exhaust flow;
a first pressure sensor (30-1) associated with a condenser (14) associated with the cooler circuit (10);
a second pressure sensor (30-2) associated with an evaporator (16) associated with the cooler circuit (10); and a controller (82) in electrical communication with the first and second pressure sensors (30-1, 30-2), configured to calculate a differential pressure;
the controller (82) being configured to determine a leak size of the condenser (14) based at least in part on the differential pressure;
the controller (82) being configured to calculate a flow rate of working fluid emissions based on the differential pressure and the leak size of the condenser (14).
[16" id="c-fr-0016]
16. Leak detection system according to claim 15, characterized in that a reduction in the purge exhaust flow rate during the elimination of vacuum and the creation of positive pressure indicates that working fluid is leaking outside. from the cooler unit (10).
[17" id="c-fr-0017]
17. Leak detection system according to claim 15, characterized in that the leak size is calculated for the evaporator (16), the condenser (14), and the cooler unit (10).
[18" id="c-fr-0018]
18. Leak detection system according to claim 15, characterized in that the refrigerant emissions due to a purge of the non-condensables are calculated on the basis of the purge exhaust flow rate and the purge efficiency.
5
[19" id="c-fr-0019]
19. Leak detection system according to claim 15, characterized in that the control device (82) is configured to calculate a flow rate of emissions of working fluid for constituents at a positive pressure based on a size respective calculated leakage, working fluid characteristics, and differential pressure by
10 in relation to the atmosphere.
[20" id="c-fr-0020]
20. Leak detection system according to claim 15, characterized in that the control device (82) is configured to calculate a flow rate of emissions of working fluid for each of the cooler unit (10), evaporator ( 16), and condenser (14).
1/4
2/4
CM
3/4 <Fig. 3
X
4/4

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FR3058218B1|2021-01-15|

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法律状态:
2018-09-20| PLFP| Fee payment|Year of fee payment: 2 |

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2019-09-19| PLFP| Fee payment|Year of fee payment: 3 |

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2020-04-10| PLSC| Search report ready|Effective date: 20200410 |

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2020-09-17| PLFP| Fee payment|Year of fee payment: 4 |

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2021-09-22| PLFP| Fee payment|Year of fee payment: 5 |

优先权:

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申请号 | 申请日 | 专利标题

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US201662415188P| true| 2016-10-31|2016-10-31|

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US62415188|2016-10-31|

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