EP0451325A2 - Plant for processing cold water and brine - Google Patents

Abstract

A plant for processing cold water and brine contains, in a gastight housing (12), at least one coolant circuit (38) which is in heat-exchange contact with a cold water/brine circuit (58, 60) or a cooling water/brine circuit (62, 64), which consists of an evaporator (40), a compressor (46) and a liquefier (42) and which contains NH3, and a cooler (80) which is connected to the cooling water or brine circuit (64) in the housing (12) to remove the heat loss occurring in the housing (12). Situated near the upper boundary (82) of the housing (12) is a spraying device (84) and in the region of the lower boundary (24) of the housing (12) a collection zone (26). The housing (12) is provided with gastight connections (58, 60, 62, 64, 86, 30) taken to the outside for the cold water or brine circuit, the cooling water supply of the liquefier, the water supply of the spraying device and the liquid drain from the collection zone (26), and with gastight connections for the electrical energy supply or for transmitting the signals from the control, regulation and monitoring devices (134, 136, 138) required. <IMAGE>

Description

The invention relates to a cold water and brine treatment system with at least one in heat exchange with a cold water brine circuit or a cooling water / brine circuit in connection, consisting of evaporator, compressor and condenser, containing NH₃ refrigerant circuit.

Insofar as the word "brine" is used in the following description and claims, this also includes antifreeze.

Many cold water and brine treatment plants are operated with fluorocarbons as refrigerants in the refrigerant circuit, but their use is undesirable because of their environmental impact. It is also known to use NH₃ as the refrigerant, which is the cheapest refrigerant from the point of view of energy use, but its use is subject to severe restrictions because of its dangerous effect on humans. Systems with NH₃ operated from a certain filling quantity may not be operated in the area of residential areas, which is why their use e.g. is not permitted for many supermarkets or catering facilities.

The invention has for its object to design a cold water and brine treatment system of the type mentioned so that despite the use of NH₃ as a refrigerant universally, e.g. in buildings or outdoors, can be used and for this purpose is almost certainly secured against any escape of NH₃ to the environment. It should also be suitable for use in brine temperatures between -40 ° C and + 20 ° C.

The solution to this problem is, according to the invention, that the at least one refrigerant circuit is arranged in a gas-tight closed housing in which a cooler for the dissipation of the heat loss occurring in the housing is connected to the cooling water or brine circuit that near the upper limit of the housing in this a de-energizing device and in the area of the lower one Limitation of the housing is arranged a collecting zone, and that the housing with gas-tight connections to the outside for the cold water or brine circuit, the cooling water supply of the condenser, the water supply to the de-irrigation device and the discharge of liquid from the collecting zone, and with gas-tight connections for the electrical power supply or signal transmission of the necessary control, regulating and monitoring devices is provided.

The hermetic encapsulation of the plant parts containing the refrigerant circuit ensures that escaping NH 3 cannot get into the atmosphere and into the surroundings of the plant to be entered by the operating personnel. Any NH₃ occurring in the interior of the housing can be deposited by the de-energizing device as ammonia in the collecting zone and discharged into containers located outside the housing, suitable for this task.

Because of the hermetic sealing of the housing, the cooler ensures that the heat loss that occurs in the housing is dissipated to the outside, the connection of the cooler with the cooling water or brine circuit inside the housing leading to the number of gas-tight leads from the housing to the outside Lines can be kept low.

In order to prevent that in the event of any leaks, an even approximately dangerous amount of NH 3 accumulate in the housing or from the housing or the coolant circuit into the Environment can escape, according to advantageous embodiments of the invention, several mutually independent monitoring devices are provided, a first of which is that a slight excess pressure is provided in the housing and a pressure monitoring device is provided in the housing, which is suitable when exceeding an upper and when Switching off the coolant circuit and switching on the de-irrigation system are below a lower limit value.

The overpressure is set to the desired value before the system is started up and remains unchanged due to the gastight design of the housing as long as no faults occur. Exceeding the upper limit value indicates that the internal pressure in the housing increases, which can be caused by the escape of NH₃. Falling below the lower limit value indicates that the overpressure in the housing is reduced, which indicates a leak in the housing. In both cases, the compressor and thus the coolant circuit can be switched off and the NH 3 which may be present in the housing is precipitated and discharged as ammonia.

Another safety measure is that a device for monitoring the liquid level in the condenser is provided and is suitable for switching off the coolant circuit and switching on the de-irrigation system when the liquid level falls below a predetermined level. A decrease occurs when the liquid level drops indicated at NH₃ in the closed refrigerant circuit, so that the escape into the interior of the housing must be expected.

Another advantageous embodiment is that an NH₃ sensor is arranged in the housing, which is suitable for switching off the coolant circuit when activated and switching on the de-energizing system. In this embodiment, the occurrence of NH₃ is determined directly and not indirectly, as in the examples described above, using auxiliary variables.

Yet another embodiment is that in the cold water or brine circuits outside the housing, the electrical conductivity of the circulating medium-testing sensors are arranged, which are suitable for switching off the coolant circuit and for switching on the de-energizing system when a limit value coordinated with the presence of NH 3 is exceeded. This embodiment makes use of the fact that the conductivity of the circulating medium changes when NH₃ penetrates into the medium, which in turn indicates a leak through which the NH₃ does not get into the interior of the housing, but via the cold water or brine circuit - albeit in a closed circuit - leaves the security area formed by the housing.

In order to facilitate the gas-tight design of the housing and to avoid the risk of explosion, according to a further advantageous embodiment, the control, regulation and monitoring devices of the system are implemented in sensor technology.

According to a particularly expedient design, the devices for electrical energy supply and for controlling, regulating and monitoring the system parts arranged in the housing are combined in a control cabinet and can be connected to the devices assigned to them in the housing via a central interface. This accommodates a compact design of the system in a modular system, which enables a particularly cost-effective adaptation to the respective application.

Another advantageous embodiment is that the refrigerant circuit is provided with a filling and emptying line, which is provided in the region of an inspection opening in the housing, which can be closed in a gas-tight manner, with a connecting piece for connecting a line extension. Through this line, the coolant circuit can, if necessary, be completely emptied, but also filled, without a line breaking through the housing wall during operation of the system.

A pressure safety device is preferably arranged between the condenser and the evaporator in such a way that excess pressure can be reduced from the condenser to the evaporator.

In terms of optimizing energy consumption and also from a safety point of view, an expedient embodiment consists in arranging several individually switchable and disconnectable coolant circuits in the housing.

In order that no damage to the drive motors of the compressors can occur in the case of NH 3 possibly emerging in the housing, such as on bearings or the winding, according to a further preferred embodiment, electrical drive motors are particularly encapsulated inside the housing. The use of aluminum windings can also prevent this danger.

A further expedient configuration which promotes the modular system consists in that the connections for the flow and return of a cooling water / brine circuit assigned to the condenser and the flow and return of a cold water / brine circuit assigned to the evaporator are combined in a connection zone on the housing wall and that this connection zone is assigned a connection unit which is traversed between a connection point assigned to the connection zone and a further connection point of the supply and return of the cooling water / brine circuit and the cold water / brine circuit and the feed pumps for the supply of both the cooling water / Contains brine circuit as well as the cold water / brine circuit, wherein according to an advantageous development, the connection unit contains switch valves that are suitable, the returns of these two circuits either with the condenser or the evaporator or via a to connect the free cooling connection with the flow of the other of these two circuits, so that the drive energy for the refrigerant circuit can be saved in the case of lower outside temperatures than the device to be cooled.

The connection unit is preferably designed as a unit that can be walked on for inspection purposes and can be set up independently. In addition, the connection unit can be prepared for the attachment or installation of the control cabinet.

Based on the following description of an embodiment of the invention shown in the drawing, this will be explained in more detail.

The figure shows a schematic vertical section through an inventive system for cold water and brine cooling.

The system is arranged in a modular system on a base frame designated overall by 10 and comprises three essential components, namely a housing 12 enclosing the NH 3 area, a connection unit 14 and an electrical control cabinet 16.

The housing 12 consists of a lower part 12a and a removable upper part 12b which can be connected gas-tight to the lower part 12a in a horizontal parting plane 18. Inspection openings 22 which can be closed gas-tight by covers 20 are also provided in the lower part 12a. At the bottom 24 of the lower part 10a, a trough-like collecting zone 26 is formed, which at its lowest point is provided with a suction nozzle 30 which can be closed gas-tight by a shut-off valve 28, via which liquid collected in the collecting zone by a suction pump 32 which can be attached from the outside via a line 34, NH₃ or an NH₃-water mixture, can be withdrawn in transport container 36.

The refrigerant circuit 38 is hermetically enclosed by the housing 12. It consists of an evaporator 40, a condenser 42, a compressor 46, which can be driven by an electric motor 44, in the line connection 48 between the evaporator 40 and the condenser 42, a line 50 returning the refrigerant from the condenser 42 to the evaporator 40, which contains an expansion device 52 , and from an overpressure line 54 between the condenser 42 and the evaporator 40 with an overpressure valve 56.

The evaporator 40 is provided with a flow connection 58 and a return connection 60 for the cold water or brine to be cooled and, in the same way, the condenser 42 with a flow connection 62 and a return connection 64 for cooling water and brine. These connections are gas-tight to the outside through a side wall 66 of the lower part 12a of the container 12 and prepared for connection to the connection pieces 68, 70, 72 and 74 assigned to them in the connection unit 14.

For filling and emptying the refrigerant circuit 38 there is a pipe socket 76 arranged on the evaporator 40, which ends in the region of an inspection opening 22 within the housing 12 and is prepared at its end provided with a shut-off valve 78 for connecting a filling and emptying line.

A cooler 80 arranged above the condenser 42 is connected between the return connection 64 for the cooling water opening into the condenser 42 for the cooling water and the corresponding flow connection 62 for dissipating the heat loss occurring within the hermetically sealed housing 12.

Near the upper limit 82 of the housing 12, a de-energizing device 84 is arranged in the housing, which can be connected to a water connection 88 via a line 86, which is guided gas-tight from the housing 12. For this purpose, a solenoid valve 90 which can be triggered by the safety devices explained below or a manually operated shut-off valve 92 arranged in the bypass is used for this purpose. The line 86 is led out of the housing 12 on the left side of the drawing in order to keep the illustration clear. In the practical implementation, however, it may be more expedient to also lead this line 86 out into the connection unit 14

On the housing 12 there is a connecting piece 96 provided with a shut-off valve 94, which serves to provide a certain, low, monitoring pressure in the housing 12 after the gas-tight assembly or before the system is started up or restarted after the housing 12 has been opened build up.

As indicated by broken lines in the drawing, instead of a single refrigerant circuit 38, several, for example three, refrigerant circuits can also be provided in the housing 12, which are symbolically represented by the additional compressors 46 'and 46''. This means that if one refrigerant circuit fails, the other two can continue to operate. In addition, the energy consumption can be better adapted to the cooling capacity required in each case.

The equipment of the refrigerant circuit 38 or the refrigerant circuits within the housing 12 with evaporators, compressors and condensers is dimensioned according to the power range to be operated. In spite of different dimensions of the refrigeration devices accommodated in the housing 12, the connections led out of the housing can always be combined in the same arrangement in a connection zone which the further lines in the connection unit 14 face in the same arrangement, so that possibly different combinations of, for example, the power range and / or the line cross section selected housings 12 on the one hand and connection units 14 on the other hand are possible.

In the same way, the configuration of a system in a modular system can be facilitated by standardized design of the connection dimensions on the connection unit 14 and on the control cabinet 16.

The flow connection 58 of the cold water connected to the evaporator 40 is continued in the connection unit 14 in a line section 158 which comprises two parallel and optionally operable delivery units, each between two shut-off valves 102 and 104 or 102 'and 104' contain a feed pump 106 or 106 'and a check valve 108 or 108'. A connection 110 is provided on the side 15 of the connection unit 14 facing away from the housing 12 for the forwarding of the cold water. The cold water returning from the cooling consumer enters the connection unit 14 again via a connection 112 and is led via a line 160 to the return connection 60 arranged in the housing 12. In the same way, the flow connection 62 of the cooling water connected to the condenser 42 continues in a line section 162, which also has two parallel delivery units with shut-off valves 114 and 116 or 114 'and 116', a delivery pump 118 or 118 'and a non-return valve 120 or 120 'and ends at a connection 122 on the side 15 of the connection unit. The cooling water returning from a suitable cooling device re-enters the connection unit 14 via a connection 124 and is led via a line 164 to the return connection 64 in the housing 12.

If the outside temperature is lower than the desired temperature of the device to be cooled, the three-way valve 130 in line 160 guides the cold water or brine returning from the consumer via a connecting line 132 to line 162 and from there via connection 122 to external cooling device, not shown. From there, the cold water or the brine flows via the connection 124 into the line 164 to a three-way valve 134, which leads the cooled cold water via a connecting line 136 to the line 158, from where it reaches the connection 110 via one of the delivery units included in the line 158 and from there to the cold consumer (not shown).

To prevent NH₃ from escaping from the system, both the penetration of NH₃ into the interior of the housing 12 and the penetration of NH₃ into the circuits of cold and cooling water leading out of the housing 12 are monitored. Several independent monitoring devices are provided to improve security.

An NH₃ sensor 134 is located in the interior of the housing 12 as a direct monitoring device.

In addition, a pressure monitoring device 136 is arranged in the housing 12, which is suitable for determining deviations from the internal pressure in the container 12 set via the connecting piece 96. If the pressure is higher, this indicates that NH₃ has escaped from the refrigerant circuit 38 into the space enclosed by the housing 12. If the pressure is less than the set overpressure of e.g. 0.1 bar, the container 12 must lose pressure through a leak, so it can no longer offer the required security.

A monitoring unit 138 is arranged on the condenser 42, which allows the liquid level to be monitored. If the liquid level drops, this indicates that the refrigerant escapes from the refrigerant circuit 38.

A device 140 is arranged in the cold water circuit and a similar device 142 for monitoring the electrical conductivity of the fluid circulating in the circuit is arranged in the cooling water circuit. Since the electrical conductivity of the fluid changes when NH₃ gets into the fluid, with a corresponding deviation of the values determined, an overflow of NH₃ from the refrigerant circuit 38 into one of the circuits leading out of the housing 12 can be concluded.

If a fault is indicated by the monitoring devices described, which are implemented in sensor technology and are connected to a PC-based switching and control device in the control cabinet 16 via electrical connections (not shown), the refrigerant circuit is stopped by switching off the compressor 46 and the solenoid valve 90 triggered, whereby the de-energizing system takes effect and the NH₃ is deposited inside the housing in the collecting zone 26, from where it - we already described - can be pumped into the transport container 36. It is possible to use the computer to set various priorities for the fault messages and to initiate countermeasures.

The system is also thermal with the other monitoring, regulating and control devices required for operating the system, such as frost protection thermostats, pressure limiters Overcurrent release, automatic restart circuit for starting after a power failure, flow monitor for cold water, operating hours counter, engine temperature display, etc. equipped, which are connected in a suitable manner to the associated devices in the control cabinet 16. There is also the possibility of storing all the running times leading to maintenance with the appropriate value in the computer and thereby determining the maintenance intervals in an economical manner depending on the running time and not performing the maintenance according to predetermined fixed time intervals.

Claims (15)

Cold water and brine treatment system with at least one in heat exchange with a cold water brine circuit (58, 60) or a cooling water / brine circuit (62, 64), consisting of evaporator (40), compressor (46) and condenser (42) , NH₃ containing refrigerant circuit (38), characterized in that the at least one refrigerant circuit (38) is arranged in a gastight closed housing (12) in which a cooler (80) for dissipating the heat loss occurring in the housing (12) with the Cooling water or brine circuit (64) is connected so that near the upper boundary (82) of the housing (12) there is a de-energizing device (84) and in the region of the lower boundary (24) of the housing (12) a collecting zone (26) is arranged, and that the housing (12) with gas-tight leads to the outside (58, 60, 62, 64, 86, 30) for the cold water or brine circuit, the cooling water supply of the condenser, the water verso tion of the de-energizing device and the discharge of liquid from the collecting zone (26), as well as gas-tight connections for the electrical energy supply or signal transmission of the necessary control, regulating and monitoring devices (134, 136, 138). System according to Claim 1, characterized in that a slight overpressure is provided in the housing (12) and in that a pressure monitoring device (136) is arranged in the housing, which is suitable when an upper limit value is exceeded and a lower value is undershot turn off the coolant circuit (38) and turn on the de-energizing system (84). System according to one of the preceding claims, characterized in that a device (138) for monitoring the liquid level in the condenser (42) is provided and is suitable for switching off the coolant circuit (38) and switching off the de-energizing system (84) when the liquid level falls below a predetermined level. System according to one of the preceding claims, characterized in that an NH₃ sensor (134) is arranged in the housing, which is suitable for switching off the coolant circuit (38) when it responds and switching on the de-energizing system (84). System according to one of the preceding claims, characterized in that sensors (140, 142) which check the electrical conductivity of the circuit medium are arranged in the cold water or brine circuits outside the housing (12) and are suitable for exceeding one for the presence of NH₃ adjusted limit switch off the coolant circuit (38) and switch on the de-energizing system (84). System according to one of the preceding claims, characterized in that the control, regulating and monitoring devices (134, 136, 138, 140, 142) of the system are implemented using sensor technology. System according to one of the preceding claims, characterized in that the devices for electrical power supply and for controlling, regulating and monitoring the system parts arranged in the housing (12) located outside the housing (12) are combined in a control cabinet (16) and via a central interface on the housing (12) can be connected to the devices assigned to them in the housing. System according to one of the preceding claims, characterized in that the refrigerant circuit (38) is provided with a filling and emptying line (76) which, in the region of an inspection opening (22) which can be closed in the housing (12) and which can be closed in a gastight manner, has a connection piece for the Connection of a line extension is provided. System according to one of the preceding claims, characterized in that a pressure safety device (54) is arranged between the condenser (42) and the evaporator (40) in such a way that an excess pressure can be reduced from the condenser (42) to the evaporator (40). System according to one of the preceding claims, characterized in that a plurality of coolant circuits which can be switched on and off individually are arranged in the housing (12). System according to one of the preceding claims, characterized in that electric drive motors (44) are particularly encapsulated in the interior of the housing. System according to one of the preceding claims, characterized in that the connections for the flow and return (62, 64) of a cooling water / brine circuit assigned to the condenser (42) and the flow and return (58, 60) of the evaporator ( 40) assigned cold water / brine circuit on the housing wall are combined in a connection zone and that this connection zone is assigned a connection unit (14), each between a connection point assigned to the connection zone (68, 70, 72, 74) and a further connection point (110, 112, 122, 124) of the supply and return of the cooling water / brine circuit and the cold water / brine circuit is crossed and the feed pumps (106, 106 ', 118, 118') for the supply of both the cooling water / brine circuit and the cold water / Brine circuit contains. Arrangement according to claim 12, characterized in that the connection unit (14) contains changeover valves (130, 134) which are suitable for the returns of these two circuits either with the condenser (42) or the evaporator (40) or via one of the free cooling systems serving connection with the flow of the other of these two circuits. Arrangement according to one of claims 12 or 13, characterized in that the connection unit (14) is designed as a unit which can be walked on for inspection purposes and which can be set up independently. Arrangement according to claim 7 and one of claims 12 to 14, characterized in that the connection unit (14) is prepared for the attachment or installation of the control cabinet (16).

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