EP3486575A1 - Device and method for a security drain of working fluid - Google Patents

Abstract

The invention relates to an apparatus and a method for safely performing a left-handed thermodynamic Clausius-Rankine cycle in a residential building by means of an inflammable working fluid which is heavier than air in the gaseous state under atmospheric conditions and in a closed, hermetically sealed refrigerant circuit (1) in which a working fluid circulates, 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 housing (6) which comprises all the devices connected to the closed refrigeration circuit (1) and may comprise further devices, the refrigeration circuit (1) being connected to a drain (11) which is located downstream of the compressor (2) is arranged below and the drain (11) you a check valve (15) and a non-return valve (12) from the refrigerant circuit (1) is separated, the housing interior (6) with the drain (11) is connected and the drain through a check valve 26) and a non-return valve (29) from the refrigerant circuit ( 1), the drain (11) is led out of the enclosure to a location outside the building (13) where there are no sinkholes, a dispersing device (14) is located at the outlet of the drain, and pressurized held inert gas in at least one inert gas container (19) is stored, and this inert gas container (19) with both the refrigerant circuit (1) and with the housing interior (6) via a respective check valve (22, 24) is connected.

Description

The invention relates to irregular conditions in refrigeration 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 private homes, rental housing complexes, hospitals, hotel complexes, restaurants, combined residential and commercial buildings and businesses in which people permanently live or work, in contrast to mobile devices such as air conditioning systems or transport boxes, or 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 percent by volume in air, which corresponds to 38 g / m ³ in air .. If the cooling process in a surrounding, hermetically sealed, but otherwise air-filled space with the working fluid propane is performed , 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 195 26 980 A1 describes an apparatus and method for cleaning closed space air having gaseous contamination. Once the contaminant is detected by a gas sensor, it controls a compressor which directs the air through an absorber in that space, thereby absorbing the contaminant. The cleaned air leaves the absorber in the closed room.

• 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 are complex, they have had little success on the market so far. 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.

The requirements are mutually exclusive and also create conflicting goals in large numbers.

It is also known to easily vent flammable and explosive working fluids to the atmosphere in the event of spills. For example, the "Federal Institute for Refrigeration and Air Conditioning Technology" in May 2012 explains that the impact on global warming in R290 is very low, so venting to the atmosphere is the usual way of disposing of this refrigerant. However, certain safety precautions had to be taken which minimized the occurrence of an explosive atmosphere as far as possible. However, the rules established for manual disposal are not suitable for emergencies where safe and automatic draining is required.

The object of the invention is therefore to provide an apparatus and a method for a safe and automatic discharge of an inflammable working fluid.

• mindestens einen Verdichter für Arbeitsfluid,
• mindestens eine Enspannungseinrichtung für Arbeitsfluid,
• mindestens zwei Wärmeübertrager für Arbeitsfluid mit jeweils mindestens zwei Anschlüssen für Wärmeüberträgerfluide,
• ein geschlossenes Gehäuse, welches alle am geschlossenen Arbeitsfluidumlauf angeschlossenen Einrichtungen umfasst und weitere Einrichtungen umfassen kann,
• wobei der Kältekreis mit einem Ablass verbunden ist, der in Strömungsrichtung dem Verdichter nachfolgend angeordnet ist und der Ablass durch ein Sperrventil vom Kältekreis getrennt ist,
• das Gehäuseinnere mit dem Ablass verbunden ist und der Ablass durch ein Sperrventil vom Kältekreis getrennt ist,
• der Ablass aus dem Gehäuse an einen Ort außerhalb des Gebäudes geführt wird,
• am Austritt des Ablasses eine Vorrichtung zum Dispergieren angeordnet ist, und
• ein unter Druck gehaltenes Inertgas in mindestens einem Behälter bevorratet wird, und dieser Behälter sowohl mit dem Kältekreis als auch mit dem Gehäuseinneren über je ein Sperrventil verbunden ist.

The invention solves this problem by a device for safely carrying out a left-handed thermodynamic Clausius-Rankine cycle process by means of an inflammable working fluid which is heavier than air in the gaseous state under atmospheric conditions and is guided in a closed, hermetically sealed working fluid circulation

• at least one compressor for working fluid,
• at least one expansion device for working fluid,
• at least two heat exchangers for working fluid, each having at least two connections for heat transfer fluids,
• a closed housing, which comprises all devices connected to the closed working fluid circulation and may comprise further devices,
• wherein the refrigeration circuit is connected to a drain, which is arranged downstream of the compressor in the flow direction and the drain is separated from the refrigeration circuit by a check valve,
• the housing interior is connected to the drain and the drain is separated from the refrigeration circuit by a check valve,
• the drain is led out of the housing to a location outside the building,
• disposed at the outlet of the drain, a device for dispersing, and
• a pressurized inert gas is stored in at least one container, and this container is connected to both the refrigerant circuit and the housing interior via a respective check valve.

As heat transfer fluids are here all gaseous or liquid media to understand, with which heat is transferred, such as air, water, brine, heat transfer oils or the like. The drain from the enclosure should be routed to a location outside the building where there are no sinks. The check valves should be secured by non-return valves against unintentional backflow.

In one embodiment of the invention it is provided that between the shut-off valve (15), which separates the drain (11) from the refrigerant circuit (1), and the drain (11) an ejector (18) is connected, which with a jet line (21) is connected via a check valve (20) to the inert gas container (19) held under pressure.

In a further embodiment of the invention it is provided that in the refrigeration circuit (1) between the compressor (2) and the condenser (3) a check valve (16) is arranged, the leading to the discharge line (17) in front of the check valve (16). branches off and the connecting line to the inert gas container (19) branches off after the check valve (16).

If a leak is detected which allows working fluid to escape into the closed housing, it depends on the size of this leakage whether and in what time period a dangerous situation could arise. Although large leaks are very rare, they are conceivable if icing has occurred in the evaporator due to a malfunction, or if massive external effects, such as earthquakes, floods, accidents or house fires, have resulted in significant mechanical damage , In such cases, the flammable inventory must be removed as quickly as possible from the danger zone.

For this purpose, the check valve behind the compressor is opened and the working fluid under pressure is discharged to the outside. Most flammable working fluids are aliphatic hydrocarbons, in the simplest case this is propane. In the following, therefore, propane is selected as an example, but the invention is not limited to propane as a working fluid.

The process of discharging into the open air is a common practice, since propane has only a small climatic impact, about 3.3 times that of carbon dioxide, which is practically negligible in the usual amounts used in refrigeration circuits. Depending on the causes and the damages that led to the leakage, however, a case distinction must be made when discharging to the outside in order to always be sure that an explosive mixture can never occur. The invention solves this problem by a method using the device according to the invention by first checking after the detection of a leak whether an ignitable mixture of working fluid and air has formed inside the housing (6) and whether in the refrigeration circuit (1). a pressure drop takes place.

The first thing to check is whether there is a pressure drop in the refrigerant circuit. In the event that no pressure drop has set, is still of a two-phase area to go out in the refrigeration cycle and a massive leakage can be ruled out first. The pressure under which the refrigeration cycle is, can then be used as a driving force for the promotion of propane in the free and it is sufficient for dispersing by means of a dispersing. The drain should not be above a sink, as propane, like almost all other flammable working fluids, is heavier than air and could sink into such a sink and create an inflammable mixture. Such sinks are, for example, secured with gratings basement windows or Gullideckel for drainage or basement stairs.

However, this measure is only feasible as long as the refrigeration cycle is under sufficient pressure and as long as no larger amount of propane has entered the housing, where an ignitable mixture could arise. In the event that hardly escapes propane into the housing and the compressor of the refrigerant circuit can continue to operate, the compressor supports the pressure build-up for draining and dispersing the propane to be deflated.

If larger amounts of propane could have entered the housing, as can be seen for example by an increase in pressure in the housing, the housing must be rendered inert immediately and the contents must also be safely released into the open. Therefore, it is provided in such a case in one embodiment of the invention that the check valve of the refrigerant circuit is closed and the check valve of the inert gas to the housing and at the same time the check valve from the housing to the drain is opened. In this case, the inert gas pushes the propane / air mixture out of the housing through the drain and at the same time causes the ignitability tendency to decrease due to the inertization.

Carbon dioxide is preferably used as the inertizing gas. When using other inert gases or gas mixtures, pay attention to their Joule-Thomson coefficient, so that no ice is formed during the pressure drop, as would be the case with the use of pure nitrogen.

In one embodiment of the method, it is therefore provided that the gaseous content of the housing is sucked off and thereby mixed with an inert gas before it is led out of the housing (6) to a location outside the building (13).

In a further embodiment of the method, it is therefore provided that, after a negative test, whether an ignitable mixture of working fluid and air has formed in the housing, and a positive check as to whether there is a pressure drop in the refrigeration circuit (1), the gaseous content of the refrigeration circuit (1) is aspirated while mixing with an inert gas before it is led out of the housing (6) to a location outside the building (13).

In both cases, it can be provided in a further embodiment of the method that the suction takes place by means of an ejector (18) and the inert gas is admixed as a propulsion jet.

In a further embodiment of the method, it is provided that, after a negative test as to whether an ignitable mixture of working fluid and air has formed in the housing, and a negative check as to whether there is a pressure drop in the refrigeration circuit (1), the working fluid under pressure directly or with the assistance of the compressor in the drain (11) is given, wherein the refrigerant circuit is interrupted by a check valve (16) between the discharge line (17) and the evaporator (3).

The last part of the propane in the refrigeration cycle is only slowly to vent by simply opening the check valve, which is undesirable in an emergency. In this case, the check valve is opened by the inert gas container to the refrigerant circuit and the refrigerant circuit is purged with inert gas under pressure.

It may also be the case that a leak occurs in one of the two heat exchangers. In such a case, protection is provided by automatic venting of the working fluid from the heat transfer fluid into the housing. This is followed by a discharge of the interior of the housing with simultaneous inerting of the housing interior.

The invention will be explained in more detail with reference to an example. It shows Fig. 1 schematically a refrigeration cycle with the refrigerant propane and the proposed safety devices using the example of a house heat pump.

Fig. 1 shows a conventional refrigeration circuit 1 with a compressor 2, a condenser 3, a pressure reduction 4 and an evaporator in a closed housing 6. The housing 6 is usually soundproof and therefore designed to be airtight, it can withstand slight overpressure. Structurally, water storage and switching elements can be integrated. The housing 6 has, in addition to a power connection not shown here, line connections for the heat source, the heat source connection 7 and the heat source supply 8, and the heating circuit with the heat sink lead 9 and the heat sink connection 10.

Of course, the refrigeration circuit shown here in simplified form may also include a plurality of heat exchangers at different temperature levels, a stepped pressure reduction, switching devices for heating operation in winter and cooling in summer, as well as a large number of sensors, but the following safety devices are identical.

In the event of an accident, a discharge line 11 leading out of the housing is provided, which is secured from the outside by a non-return valve against suction and ends outside the residential building wall 13 in a disperser 14. In the present example, the disperser is designed as a swirl diffuser, depending on local conditions, a variety of other types are possible. It is important that, if possible, no Strands form and that the highest possible air mixing takes place, so that a safe distance to the ignition limits to a forming propane-air mixture is formed when propane is discharged.

The type of safe discharge of propane depends on the nature of the accident or on the quality of the information and the circumstances that exist. Here external conditions such as power failure, fire, earthquake, flood and accidents of internal events such as the occurrence of leaks or very rare major disturbances and those resulting from the interaction with external heat sources and heat sinks connected to distinguish. The detection means required for this purpose are not the subject of the invention, but are assumed to be present in the following as in the context of the known state of the art and not shown separately.

If a small leak is detected, the exact location or repair of which requires a depleted refrigerant circuit, or it must be assumed to increase rapidly, the discharge check valve 15 is opened, the pressure reduction valve 4 is opened and the refrigerant circuit check valve 16 is closed , The propane flowing under pressure into the ejector feed line 17 is directed into the ejector 18, but does not need to be supported by propellant gas. Depending on the external conditions, it may be useful, however, to admix the inert gas entering the ejector from the inert gas pressure vessel 19 by opening the propellant gas blocking valve 20, which may also be designed as a control valve, and the inert gas via the propellant gas Supply line 21 in the ejector mixes with the propane.

As long as a two-phase mixture of propane is in the refrigeration cycle, the pressure in the refrigerant circuit is essentially constant and only dependent on the temperature. As long as the heat source and heat sink connections are closed, the temperature remains largely constant, since the existing in the housing 6 in the capacitor 3 heat capacity compensates for the loss of heat of evaporation of the propane. Most of the propane can be drained this way. The situation is different when there is no hot water in the condenser. Then, a drop in temperature and, associated therewith, a pressure drop in the refrigeration circuit must be expected.

As soon as the propane pressure in the refrigeration circuit drops, the compressor 2 can be used for further delivery and pressure increase, provided that there is no power failure or compressor failure. In addition, the check valve 22 may be opened to fill inert gas from the inert gas pressure vessel 19 into the refrigeration cycle 1 and maintain the pressure. In the event of a power failure, inert gas can also be added from the propellant gas line 21 into the ejector 18 at decreasing pressure in order to remove propane from the refrigeration circuit and with such a pressure in the disperser 14 that there is still sufficient turbulence or mixing with the outside air , Once the propane is removed from the refrigeration circuit 1 by displacement with inert gas, the drain check valve 15 and the refrigerant circuit inerting check valve 22 can be closed.

Following this, the housing 6 has to be purged with inert gas, since too much propane could still be present in the housing due to the previous propane leakage. For this purpose, the housing evacuation check valve 26 is opened, through the evacuation inlet 27 and the filter 28, air can be sucked from the housing 6 in the Ejektorzulaufleitung 17 in this way. A non-return valve 29 ensures that malfunction could cause residual propane to flow into the housing. By the propellant gas-blocking valve 20 is opened, the loaded air can be sucked out of the housing by means of the ejector 18. In order to avoid damage to the housing 6 by negative pressure, the Gehäuseinertisierungs-check valve 24 is opened at the same time, which is so much Inert gas can flow through the Inertgasauslass 25 in the housing, as is discharged through the evacuation inlet 27. Preferably, the known pendulum gas method is used here.

If a major accident is to be feared or in the event that it burns, a quick release is required. In this case, the procedure is as described above, but the refrigerant circuit check valve is not closed. The housing evacuation check valve is also opened from the beginning to counteract any resulting pressure in the housing, either by escaping propane or by external heat. If damage to the housing has already taken place and there are no people in the vicinity, the housing deactivation shut-off valve is also opened in order to reduce the risk of fire outside the housing.

In the event of an earthquake or flood, on the other hand, all stop valves are closed until it is ensured that the drain devices are undamaged and free. After that it will be decided on a case-by-case basis if and when a release is necessary.

The same applies in principle also in the case that the disturbances concern only the heat source or heat sink cycle. If, however, leakage in the refrigeration cycle could lead to a rise in propane in the heat source or heat sink circuit, ie if heat transfer fluid could also enter the refrigeration circuit in the event of a pressure drop, the pressure in the refrigeration cycle must be maintained at the pressure of the heat transfer fluid. For this purpose, at first only the refrigeration circuit inerting shut-off valve 22, which can also be designed as a control valve for this case, is opened in order to feed inert gas into the refrigeration circuit 1 and to increase the pressure slightly. At the same time, the connections 7 to 10 are closed. Depending on the amount of heat transfer fluid that may have entered, the propane removal must be carried out under pressure, with the compressor switched off is and the ejector is operated with propellant gas. In this way, a safe propane discharge is ensured even with entrainment of heat transfer fluid.

LIST OF REFERENCE NUMBERS

1

cooling circuit

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

drain line

12

arrestor

13

outside wall

14

disperser

15

Discharge block valve

16

Cooling circuit shut-off valve

17

Ejektorzulaufleitung

18

ejector

19

Inert gas pressure vessel

20

LPG shut-off valve

21

LPG supply

22

Kältekreisinertisierungs shutoff valve

23

arrestor

24

Gehäuseinertisierungs shutoff valve

25

Intergasauslass

26

Housing evacuation check valve

27

evacuation intake

28

filter

29

arrestor

Claims (9)

Apparatus for safely conducting a left-handed thermodynamic Clausius-Rankine cycle in a dwelling by means of an inflammable working fluid heavier than air in the gaseous state under atmospheric conditions and conducted in a closed, hermetically sealed refrigeration circuit (1) in which a working fluid circulates, including 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 housing (6), which comprises all devices connected to the closed refrigeration circuit (1) and may comprise further devices, characterized in that - The refrigerant circuit (1) with a drain (11) is connected downstream of the compressor (2) is arranged and the drain (11) by a check valve (15) from the refrigerant circuit (1) is separated, - The housing interior (6) is connected to the drain (11) and the drain through a check valve 26) is separated from the refrigerant circuit (1), - the drain (11) from the housing to a location outside the building (13) is feasible, - At the outlet of the drain, a device for dispersing (14) is arranged, and - An inert gas under pressure in at least one inert gas container (19) is stored, and this Inertgasbehälter (19) with both the refrigerant circuit (1) and the housing interior (6) via a respective check valve (22, 24) is connected. Apparatus according to claim 1, characterized in that between the shut-off valve (15) which separates the drain (11) from the refrigerant circuit (1) and the drain (11) an ejector (18) is connected, which with a propellant jet line (21) via a check valve (20) is connected to the inert gas container (19) held under pressure. Device according to one of claims 1 or 2, characterized in that in the refrigerant circuit (1) between the compressor (2) and the condenser (3) a check valve (16) is arranged, wherein the leading to the discharge line (17) in front of the check valve (16) branches off and the connecting line to the inert gas container (19) branches off after the check valve (16). A method for safety evacuation of a refrigeration circuit and the housing comprising it according to one of claims 1 to 3, together at least 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 housing (6), which comprises all devices connected to the closed refrigeration circuit (1) and may comprise further devices, - The refrigerant circuit (1) with a drain (11) is connected downstream of the compressor (2) is arranged and the drain (11) by a check valve (15) from the refrigerant circuit (1) is separated, - The housing interior (6) is connected to the drain (11) and the drain through a check valve (26) from the refrigerant circuit (1) is separated, - The drain (11) from the housing to a location outside the building (13) is guided, at the outlet of the discharge, a device for dispersing (14) is arranged, and - An inert gas under pressure in at least one inert gas container (19) is stored, and this Inertgasbehälter (19) with both the refrigerant circuit (1) and the housing interior (6) via a respective check valve (22, 24) is connected. characterized in that after the detection of a leak, it is first checked whether an ignitable mixture of working fluid and air has formed in the interior of the housing (6), - And whether in the refrigerant circuit (1), a pressure drop occurs. A method according to claim 4, characterized in that after a positive examination of whether an ignitable mixture of working fluid and air has formed in the housing, first the interior of the housing (6) is rendered inert by the check valve (26), which the interior of the Housing (6) with the drain (11) connects, is opened and at the same time inert gas from the inert gas container (19) is passed into the interior of the housing. A method according to claim 5, characterized in that the gaseous content of the housing is sucked off and thereby mixed with an inert gas before it is led out of the housing (6) to a location outside the building (13). A method according to claim 4, characterized in that after a negative test, whether an ignitable mixture of working fluid and air has formed in the housing, and a positive test, whether in the refrigerant circuit (1) a pressure drop takes place, the gaseous content of the refrigerant circuit (1 ) is sucked while being mixed with an inert gas before it is led out of the housing (6) to a location outside the building (13). Method according to one of claims 6 or 7, characterized in that the suction takes place by means of an ejector (18) and the inert gas is admixed as a propulsion jet. A method according to claim 4, characterized in that after a negative examination of whether an ignitable mixture of working fluid and air has formed in the housing, and a negative test, whether in the refrigerant circuit (1), a pressure drop takes place, the working fluid under pressure directly or with the aid of the compressor in the drain (11) is given, wherein the refrigerant circuit is interrupted by a check valve (16) between the drain line (17) and the evaporator (3).

Images