EP3543629A1 - No leak housing for a cycle process - Google Patents

Abstract

Device for safely carrying out a left-handed thermodynamic Rankine cycle and its safe emptying and filling by means of an inflammable working fluid, which is guided in a closed, hermetically sealed working fluid circuit (1), comprising at least one compressor (2) for working fluid, at least one expansion device (4) for working fluid, at least two heat exchangers (3, 5) for working fluid, each having at least two ports (7, 8, 9, 10) for heat transfer fluids, a closed, gas-tight and pressure-resistant housing (6), all on the closed working fluid circuit ( 1) connected devices and pressure-tight connections, including electrical signal lines and electrical power supply to the outside of the housing, and is designed for the technically possible maximum pressure in the event of failure, wherein the housing is tubular, wherein the length-to-diameter ratio is at least 3, the housing has at least one connection for adjusting the internal pressure, inside the housing pressure and temperature measuring devices are provided.

Description

The invention relates to irregular states in working fluid circuits, in which a working fluid acting as a refrigerant is conducted in a thermodynamic cycle, such as the Rankine cycle. These are mainly heat pumps, air conditioners and refrigerators, as they are used in residential buildings. Residential buildings are understood to mean private houses, rental housing complexes, hospitals, hotel complexes, restaurants and combined residential and commercial buildings in which people live and work permanently, in contrast to mobile devices such as car air conditioners or transport boxes, or even industrial equipment or medical devices. What they all have in common is that they use energy to generate useful heat or useful cooling and form heat-transfer systems.

The used thermodynamic cycles have long been known, as well as the safety problems that can arise when using suitable working fluids. Apart from water, the best known working fluids at the time are combustible and poisonous. In the past century, they led to the development of safety refrigerants consisting of fluorinated hydrocarbons. However, it turned out that these safety refrigerants damage the ozone layer, lead to global warming, and that their safety-related harmlessness led to constructive inattentiveness. Up to 70% of the turnover was accounted for by the refill demand of leaking equipment and its leakage losses, which was accepted as long as this was considered economically justifiable in individual cases and promoted the need for replacement procurement.

The use of these refrigerants was therefore subject to restrictions, in the European Union, for example, by the F-Gas Regulation (EU) 517/2014.

• Im Normalbetrieb muss die Anlage absolut dicht sein.
• Weder bei einer Leckage im Kondensator noch bei einer Leckage im Verflüssiger darf

On the one hand, therefore, it is extremely problematic to adopt the constructive principles for refrigerant-carrying thermodynamic processes, which have proven to work well in safety refrigerants, and, secondly, to set up the system concepts from the time before the introduction of safety refrigerants. This is also due to the fact that in the meantime individual devices have become complex systems, which has multiplied the number of possibilities for disturbances and their consequences. This results, for example, in the following requirements for the security concept:

• In normal operation, the system must be absolutely leak-tight.
• Neither in case of a leakage in the condenser nor in case of a leak in the condenser

• Es darf kein Arbeitsfluid aus dem Kältekreislauf unbemerkt entweichen können.
• Im Verdichter darf das Arbeitsfluid nicht durch die Lagerung entweichen.
• Im Entspannungssystem darf das Arbeitsfluid nicht durch den Ventilsitz diffundieren oder durch Kavitation zu Leckagen führen.
• Gekapselte Teile müssen für Wartungs- und Kontrollzwecke zugänglich bleiben.
• In Notfällen dürfen sich keine Gefahren einstellen.
• Die Anlage soll in vorhandene Räumlichkeiten integrierbar sein
• Das Kältemittel soll abgelassen und eingefüllt werden können.

Working fluid get into the coupled Nutzwärme- or Nutzkältekreislauf.

• No working fluid from the refrigeration cycle should escape unnoticed.
• In the compressor, the working fluid must not escape through storage.
• In the expansion system, the working fluid must not diffuse through the valve seat or lead to leaks due to cavitation.
• Encapsulated parts must remain accessible for maintenance and inspection purposes.
• In emergencies, no hazards may arise.
• The system should be integrable into existing premises
• The refrigerant should be drained and filled.

The concept of emergency needs to be widely seen. Power failures, earthquakes, landslides, floods, fires, technical faults and climatic extremes are possible. If the systems are operated in a network, a power failure or a network fault must also be regarded as an emergency. Against such dangers or disorders the device should be inherently safe. But also a failure of the available primary energy can justify an emergency and must not lead to a danger development. All these emergencies can also occur in combination.

• Haushaltskühlschränke,
• Haushaltsgefrierschränke,
• Haushaltstrockner,
• Haushaltskühl-Gefrierkombinationen,
• Kühlkammern für Hotel- und Gastronomie,
• Gefrierkammern für Hotel- und Gastronomie,
• Klimaanlage für Haus, Hotel- und Gastronomie,
• Warmwassererzeugung für Haus, Hotel- und Gastronomie,
• Beheizung für Haus, Hotel- und Gastronomie,
• Sauna-Schwimmbadanlagen für Haus, Hotel- und Gastronomie,
• Kombinierte Anlagen für die oben genannten Anwendungen,

wobei diese Aufzählung nicht vollständig ist.Here, the different types and applications for such thermodynamic cycles have to be considered separately, for stationary systems for residential buildings, for example, the following:

• Household refrigerators,
• Household freezers,
• Household dryer,
• Household refrigerators,
• Cooling chambers for hotel and restaurant,
• Freezers for hotels and restaurants,
• Air conditioning for home, hotel and gastronomy,
• Hot water production for the house, hotel and gastronomy,
• Heating for home, hotel and gastronomy,
• Sauna swimming pool systems for the home, hotel and gastronomy,
• Combined equipment for the above applications,

this enumeration is not complete.

• Erdwärme aus Erdwärmespeichern,
• Geothermische Wärme,
• Fernwärme,
• Elektrische Energie aus allgemeiner Stromversorgung,
• Elektrische Solarenergie,
• Solarwärme,
• Abwärme,
• Warmwasserspeicher,
• Eisspeicher,
• Latentwärmespeicher,
• Fossile Energieträger wie Erdgas, Erdöl, Kohle,
• Nachwachsende Rohstoffe wie Holz, Pellets, Biogas,
• Kombinationen aus den oben genannten Energiequellen,

wobei auch diese Aufzählung nicht vollständig ist.The energy for the operation of the plants including the heat energy to be shifted can come from different sources:

• Geothermal energy from geothermal energy storage,
• Geothermal heat,
• district heating,
• Electrical energy from general power supply,
• Electric solar energy,
• Solar heat
• waste heat
• Hot water tank,
• ice storage,
• Latent heat storage,
• Fossil fuels such as natural gas, oil, coal,
• Renewable resources such as wood, pellets, biogas,
• Combinations of the above energy sources,

although this enumeration is not complete.

The problems encountered in the safety design of such systems are described in the WO 2015/032905 A1 clearly described. Thus, the lower ignition limit of propane as working fluid is about 1.7% by volume in air, which corresponds to 38 g / m ³ in air. If the refrigeration process is carried out in a surrounding, hermetically sealed, but otherwise air-filled space with the working fluid propane, the problem arises of recognizing a critical, explosive situation after a disturbance in which the working fluid escapes into this hermetically sealed space. Electric sensors for the detection of critical concentrations are difficult to perform explosion-proof, therefore, especially the propane detection by the sensors themselves significantly increases the risk of explosion, with the exception of infrared sensors. Propane is also poisonous, with inhalation above a concentration of about 2 g / m ³ narcotic effects, headache and nausea occur. This applies to persons who are supposed to solve a recognized problem on site, even before the risk of explosion.

Propane is also heavier than air, so sinks in still air on the ground and accumulates there. So if a part of the propane in a flow-poor zone of the closed space in which the disturbed unit is collect, the local explosion limits can be achieved much faster than can be expected from the quotient of total volume of volume to leaked amount of propane. The WO 2015/032905 A1 seeks to solve this problem by an electric current generator in the opening or its interlocking this space is integrated and when actuated in a first step generates and provides the electrical energy with which the sensor is activated, and in the event of an alarm Lock then does not release, but causes a ventilation of the enclosed space, and only in a second step, an unlocking and opening allows.

From the very beginning of compression refrigeration technology, an attempt was made to create a closed space where all the equipment could be safely stored and completely enveloped. The DE-PS 553 295 describes an encapsulated compression refrigeration machine in which the refrigerant compressor 1, its drive motor 2, evaporator 3, condenser 4 and control valve 5 are enclosed in a double-walled capsule 6 and 7, respectively. In the space between the double-walled capsule, a negative pressure is created and leaks, which could occur at the openings for cooling water and brine, sucked. The aspirated working fluid can subsequently be recovered if necessary. It should be noted that there is no ambient air within the encapsulated space and due to the negative pressure in the double jacket also can not penetrate into the encapsulated interior.

The DE 41 14 529 A1 describes a safety device for a filled with a dangerous medium refrigeration system, which consists of at least one complete refrigeration unit comprising a refrigerant circuit with evaporator, compressor and condenser, and a drive motor. The system is enclosed gas-tight, the enclosure is designed after the technically possible maximum pressure in the event of failure, and from the enclosure, the connections for the refrigerant, a coolant and electrical supply, monitoring and control lines are pressure-tight to the outside. It can be connected to a surge tank.

The EP 1 666 287 describes a vehicle air conditioner with a refrigerant receiver that communicates with a gas-liquid separator via an externally controllable valve. By means of a pressure sensing device, the valve can be closed when the detected pressure becomes equal to a predetermined pressure. The signal for opening the valve can be made by leakage detection.

• Montagefreundlichkeit: Im Falle von Modernisierungen von alten Heizungsanlagen müssen die neu zu installierenden Vorrichtungen zerlegbar und transportabel sein. Beispielsweise müssen sie über Kellertreppen und in verwinkelte und niedrige Kellerräume verbracht werden können. Zusammenbau, Inbetriebnahme und Wartung müssen ohne großen Aufwand vor Ort möglich sein. Dies schließt große und schwere Druckbehälter weitgehend aus, ferner Systeme, die nach einer Havarie nicht mehr demontierbar sind.
• Diagnosefreundlichkeit: Die Betriebszustände sollten von außen gut erkennbar sein, dies betrifft die Sichtbarkeit und Prüfbarkeit bezüglich möglicher Leckagen und schließt den Füllstand des Arbeitsfluids sowie den Befüllungsgrad ggf. eingebrachter Sorbentien ein.
• Wartungsfreundlichkeit: Systemdiagnosen sollten ohne großen zusätzlichen Aufwand erfolgen können. Sicherheitsrelevante Systeme sollten regelmäßig getestet bzw. auf ihre Zuverlässigkeit geprüft werden können. Sofern Systemdiagnosen nicht einfach durchführbar sind, sollten möglicherweise belastete Teile leicht durch Neuteile austauschbar sein.
• Ausfallsicherheit: Die System sollen einerseits gegen Störungen gesichert sein, gleichzeitig aber zuverlässig laufen können, wenigstens im Notbetrieb. Im Falle einer vorübergehenden externen Störung sollten die Systeme entweder selbstständig wieder anfahren oder ohne großen Aufwand wiederangefahren werden können.
• Energieeffizienz: Die Anlagen sollen energetisch günstig betrieben werden können, ein hoher Eigenverbrauch an Energie für Sicherheitsmaßnahmen wirkt dem entgegen.
• Robustheit: Im Falle größerer Störungen, seien sie extern oder systemintern aufgeprägt, muss die Beherschbarkeit gewährleistet sein, dies betrifft z.B. Lüftungssysteme, die verstopfen können oder Druckbehälter, die unter Druck stehen oder heiß werden, etwa bei einem Brand.
• Kosten: Die Sicherheitsmaßnahmen sollen weder bei den Anschaffungskosten noch bei den laufenden Kosten bedeutend sein und die Einsparungen bei den Energiekosten gegenüber herkömmlichen Systemen übersteigen. Sie sollen günstig sein.

The presented systems have so far had little success on the market. This can be attributed to the following reasons:

• Easy to install: In the case of modernization of old heating systems, the devices to be newly installed must be dismountable and transportable. For example, they must be able to be passed through cellar stairs and into winding and low cellar rooms. Assembly, commissioning and maintenance must be possible on site with little effort. This largely excludes large and heavy pressure vessels, and systems that can not be dismantled after an accident.
• Diagnostic friendliness: The operating conditions should be easily recognizable from the outside, this concerns the visibility and testability with regard to possible leaks and includes the level of the working fluid and the degree of filling of any incorporated sorbents.
• Easy to maintain: System diagnostics should be easy to do. Security-relevant systems should be regularly tested or checked for reliability. If system diagnostics are not easy to perform, potentially contaminated parts should be easily interchangeable with new parts.
• Resilience: The system should on the one hand be protected against interference, but at the same time be able to run reliably, at least in emergency mode. In the case of a temporary external fault, the systems should either restart automatically or be restarted without great effort.
• Energy efficiency: The plants should be able to operate in an energy-efficient manner, a high self-consumption of energy for safety measures counteracts this.
• Robustness: In the case of major faults, external or intrinsic to the system, it must be possible to be intact, such as ventilation systems that can clog up or pressure vessels that are under pressure or become hot, such as during a fire.
• Costs: The security measures should not be significant in terms of cost of acquisition or ongoing costs, and should exceed energy cost savings over traditional systems. They should be cheap.

In the case of retrofits, there is often little space available, for example when replacing gas water heaters in bathrooms or in places that are difficult to access or narrow. Often, there is also an old chimney in the vicinity, which leads into the open air and is no longer to be used for exhaust gas, but can be used to hold lines for working fluid, emergency lowering pipes and power cables.

The object of the invention is therefore to provide a simple, easy to install and maintenance-free device for heating or for air conditioning, the problems solved better solves and no longer has the disadvantages.

• mindestens einen Verdichter (2) für Arbeitsfluid,
• mindestens eine Enspannungseinrichtung (4) für Arbeitsfluid,
• mindestens zwei Wärmeübertrager (3, 5) für Arbeitsfluid mit jeweils mindestens zwei Anschlüssen (7, 8, 9, 10) für Wärmeüberträgerfluide,
• ein geschlossenes, gasdichtes und druckbeständiges Gehäuse (6),
• welches alle am geschlossenen Arbeitsfluidumlauf (1) angeschlossenen Einrichtungen sowie druckdichte Anschlüsse, auch für elektrische Signalleitungen und elektrische Stromversorgung nach außerhalb des Gehäuses umfasst,
• und nach dem im Störfall technisch möglichen Höchstdruck ausgelegt ist, wobei
• das Gehäuse rohrförmig ist, wobei das Länge-zu-Durchmesser-Verhältnis mindestens 3 beträgt,
• das Gehäuse über mindestens einen Anschluss zum Einstellen des Innendrucks verfügt,

The invention solves this problem by a device for safely carrying out a left-handed thermodynamic Clausius-Rankine cycle and its safe emptying and filling by means of an inflammable working fluid, which in a closed, hermetically sealed working fluid circulation (1) is performed, comprising

• at least one compressor (2) for working fluid,
• at least one expansion device (4) for working fluid,
• at least two heat exchangers (3, 5) for working fluid, each having at least two connections (7, 8, 9, 10) for heat transfer fluids,
• a closed, gas-tight and pressure-resistant housing (6),
• which comprises all devices connected to the closed working fluid circuit (1) as well as pressure-tight connections, also for electrical signal lines and electrical power supply to the outside of the housing,
• and after the technically possible maximum pressure is designed in case of failure, wherein
• the housing is tubular, the length to diameter ratio being at least 3,
• the housing has at least one connection for adjusting the internal pressure,

The design at a very high pressure ,. which can occur in case of failure makes such a construction in the usual types very heavy and unwieldy. Pressure vessels can be significantly more than 100 kilograms, and a maintenance in which the pressure vessel must be screwed, lifted and sealed again after maintenance, is hardly possible on site. Apart from the typical refrigerator-like dimensions and instead uses a pipe, the problem is that the commonly used components no longer fit, this concerns in particular plate heat exchangers for evaporator and condenser, while compressors and throttlings are also available in narrow designs ,

For pressure-resistant pipes are relatively easy and can be well sealed with flange at the ends by known means. A stainless steel pipe designed for 50 bar with a wall thickness of 4 millimeters and a diameter of 0.2 meters weighs only approx. 22 kg per meter. Even with internals such a device with a length of 1 meter to 1.60 meters of 2 people can be well transported and placed on stairs. In one embodiment of the invention, it is therefore provided that the length-to-diameter ratio is between 5 and 8.

Further embodiments relate to the heat exchangers used for evaporator and condenser. Preferably, here U-tube heat exchanger bundles are used, in which the heat transfer fluids are performed, while the evaporation and condensation processes in the outer space, which is preferably carried out in pot form, take place. This arrangement also prevents full and empty running.

For emergencies, a safety valve can be provided which leads into a pipe whose outlet leads to the outside. Such a conduit may have a small diameter, for example 10 or 12 millimeters, allowing for installation in a disused chimney.

In normal operation, a vacuum can be applied in the interior, thus preventing an ignitable mixture from forming in the event of a leak. Also, in this case, a leak can be detected by a pressure increase. Instead of a vacuum, it is also possible to carry out inerting by means of nitrogen or carbon dioxide. For this purpose, a connection for filling in inert gas is provided in one embodiment of the invention.

If smaller systems are provided, such as for generating hot water while providing air conditioning, the construction can also be similar to filter cartridges that instead of an on-site maintenance easily replaced at regular intervals and as a deposit system to a collection point for treatment can be delivered.

Fig. 1 shows a schematic diagram of a working fluid circuit 1 with a compressor 2, a condenser 3, a pressure reduction 4 and an evaporator 5 in a closed housing 6. The housing 6 has a heat source connection 7, a heat source flow 8, a heat sink flow 9th and a heat sink port 10. The working fluid circuit 1 is in this example with the flammable working fluid propane, which is also known under the name R290 operated. Shown are no fittings such as shut-off, of course, the expert will provide this and kickback.

The device can be emptied via the emergency trigger 11, the safety valve 12 and the check valve 13 into the open 14 and can be filled via the filling valve 15 with inert gas. The temperature and pressure control can be done by means of the pressure / temperature measurement 16.

LIST OF REFERENCE NUMBERS

1

Working fluid circulation

2

compressor

3

capacitor

4

pressure reduction

5

Evaporator

6

casing

7

Heat source connection

8th

Brine flow

9

Heat sinks Lead

10

Heat sinks port

11

Notabzug

12

safety valve

13

check valve

14

Lead into the open

15

Inert gas / vacuum connection

16

Pressure / Temperature Measurement

Claims (6)

Device for the safe implementation of a left-handed thermodynamic Clausius-Rankine cycle process and its safe emptying and filling by means of an inflammable working fluid, which in a closed, hermetically sealed working fluid circuit (1) is performed, comprising at least one compressor (2) for working fluid, at least one expansion device (4) for working fluid, at least two heat exchangers (3, 5) for working fluid, each having at least two connections (7, 8, 9, 10) for heat transfer fluids, a closed, gas-tight and pressure-resistant housing (6), comprising all the devices connected to the closed working fluid circuit (1) as well as pressure-tight connections, also for electrical signal lines and electrical power supply to the outside of the housing, - and after the technically possible maximum pressure is designed in case of failure, characterized in that the housing is tubular, the length-to-diameter ratio being at least 3, the housing has at least one connection for adjusting the internal pressure, - Are provided within the housing pressure and temperature measuring devices. Device according to claim 1, characterized in that the length-to-diameter ratio is between 5 and 8. Device according to one of claims 1 or 2, characterized in that the heat exchanger for working fluid have a pot design with U-shaped tube bundles. Device according to one of claims 1 to 3, characterized in that a drain is provided with a safety valve. Device according to one of claims 1 to 4, characterized in that a connection is provided for filling inert gas. Device according to one of claims 1 to 4, characterized in that the working fluid is propane and that the housing is kept under vacuum.

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