DE102017126947A1 - Fluid adsorption with inert gas displacement - Google Patents

Abstract

The invention relates to a device for safely performing 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, comprising at least one compressor for working fluid, at least an 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 circuit, may comprise further devices, and is lined with an adsorbent, which is capable of working fluid adsorbing, an adsorbent is used, which can adsorb the working fluid and an inert gas, wherein the working fluid has a higher adsorptive binding to the adsorbent as the inert gas, and wherein the adsorbent, with which the housing is lined, is pre-loaded saturated with the inert gas.

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 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 Arbeitsfluid in den gekoppelten Nutzwärme- oder Nutzkältekreislauf gelangen.
• - 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.

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 leakproof.
• - Neither in the case of a leakage in the condenser nor in the case of a leak in the condenser may working fluid enter the coupled useful heat or useful refrigeration cycle.
• - No working fluid must escape from the refrigeration cycle 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 control purposes.
• - In emergencies, no hazards may occur.
• - 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. The device should be inherently safe against such hazards or interference. 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 fridge-freezers,
• - cooling chambers for hotels and restaurants,
• - freezer rooms for hotels and restaurants,
• - air conditioning for the house, hotel and gastronomy,
• - hot water production for the house, hotel and gastronomy,
• - heating for house, 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 electricity 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 enclosed compression refrigeration machine in which the refrigerant compressor 1 , its drive motor 2 , Evaporator 3 , Liquefier 4 and control valve 5 in a double-walled capsule 6 or. 7 are included. 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 10 2011 116 863 A1 describes a method for securing a device for a thermodynamic cycle, which is operated with a process fluid containing or consisting of at least one environmentally hazardous, toxic and / or inflammatory substance. In the event of a leak in the thermodynamic cycle apparatus, an adsorbent is contacted with the process fluid, particularly ammonia, propane or propene, and the substance is selectively bound by the adsorbent. The adsorbent is regenerated after use. As adsorbent zeolite, also in combination with imidazole or phosphates, further CuBTC proposed, the adsorbent may be provided in the form of a bed, a shaped body, a paint, a spray film or a coating. The support structure of the molding may consist of microstructure, lamellar structure, tube bundle, pipe register and sheet metal and must be mechanically stable and strong surface enlarging. A circulation of the potentially contaminated air is usually continuous, but can also be initiated by a sensor that turns on the ventilation after reaching a threshold value or in the event of a detected accident. The adsorption can be carried out inside or outside a closed space.

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.

The DE 195 25 064 C1 describes a refrigerator with a gas-tight housing, which accommodates all refrigerant-carrying components of the machine, a space connecting the interior of the gas-tight housing with an outlet space is provided, and the space is filled with a refrigerant sorbing substance. The amount of sorbent material is dimensioned so that the entire amount of any escaping refrigerant can be absorbed and kept away from the environment. The space filled with the sorbent material is open to the environment. For refrigerants that are heavier than air, the space is open at the bottom, for those that are lighter, it is open at the top, so that a delivery fan is not required. The sorbent is introduced into the housing and encloses the chiller and the refrigerant-carrying facilities completely. On its way out, baffles are provided to prevent short circuit currents and force escaping gas through the sorbent. A double-walled embodiment in which the sorbent is arranged in the double jacket is also possible. At the exit of the space filled with the sorbent substance to the environment, a measuring device for refrigerant can be provided.

The EP 3 106 780 A1 describes a heat pump system housed in a binder lined airtight housing. Within this housing, an adsorption unit can be arranged with a forced ventilation, which cleans the air in the housing in recirculation mode. This recirculation mode can be continuous or only in case of failure or at regular intervals. Downstream of this sorption stage, a pilot burner, a pilot flame, a catalytic burner or a heating wire can be arranged, which burns possibly residual combustible impurities. Also conceivable is a fresh air supply in connection with the discharge of purified exhaust air.

• - 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 Beherrschbarkeit 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 regarding possible leaks and includes the level of the working fluid and the degree of filling of any incorporated sorbents.
• - Serviceability: System diagnostics should be able to be done without much extra effort. 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 be both 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 are to be operated at low energy cost, a high self-consumption of energy for security measures counteracts.
• - Robustness: In the case of major faults, external or intrinsic to the system, controllability must be ensured, eg ventilation systems that can clog 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 both initial cost and ongoing costs and should exceed the energy cost savings over traditional systems. They should be cheap.

The object of the invention is therefore to provide an improved lining device which solves the problems presented better and no longer has the disadvantages.

• - mindestens einen Verdichter für Arbeitsfluid,
• - mindestens eine Entspannungseinrichtung 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, weitere Einrichtungen umfassen kann, und mit einem Adsorbens ausgekleidet ist, welches in der Lage ist, Arbeitsfluid zu adsorbieren,
• - wobei ein Adsorbens eingesetzt wird, welches das Arbeitsfluid und ein Inertgas adsorbieren kann,
• - wobei das Arbeitsfluid eine höhere adsorptive Bindung an das Adsorbens als das Inertgas aufweist,
• - und wobei das Adsorbens, mit dem das Gehäuse ausgekleidet wird, mit dem Inertgas gesättigt vorbeladen 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, may comprise further devices, and is lined with an adsorbent which is able to adsorb working fluid,
• wherein an adsorbent is used which can adsorb the working fluid and an inert gas,
• wherein the working fluid has a higher adsorptive binding to the adsorbent than the inert gas,
• - And wherein the adsorbent, with which the housing is lined, is pre-loaded saturated with the inert gas.

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 advantage here is that in the case of a leakage with release of the working fluid, a displacement of the inert gas from the adsorbent takes place with simultaneous adsorption of the working fluid. The displaced inert gas thereby inertizes the interior of the container and at the same time reduces the danger of explosion. In addition, the desorption of the displaced inert gas causes the adsorptive heating of the adsorbent during adsorption significantly lower, since no longer the entire heat of adsorption is free, but only the difference between the heat of adsorption of the working fluid and the heat of desorption of the inert gas. This also prevents already adsorbed working fluid is expelled by heat development again.

In a particular embodiment of the invention, propane is used as the working fluid, activated carbon as the adsorbent and carbon dioxide as the inert gas. The activated carbon can be doped in a known manner such that an optimal loading is carried out by propane, but a chemisorption is to avoid this, since then the same desorption of carbon dioxide fails.

Apparently, such a lining is preferably made by dimensionally stable mats or moldings containing the adsorbent and can be easily removed and removed after opening the housing. They are typically permeable to gas and liquid on the side facing the interior of the container by means of a holding grid, while the dimensional stability is ensured by a stable rear-side structure.

In one embodiment of the invention, it is provided that these mats or moldings on the inside facing the housing have a flat surface and on its upper side pull-down foil-like blinds that are pulled in the event of disassembly as a bag over the surface and then for the Disassembly and removal must be kept closed. In a further embodiment of the invention, this device is also used for assembly in order to prevent the inert gas from prematurely diffusing out of the lining.

On the back of the mats or moldings are fixed in a known manner by hooks or click fasteners.

• 1 einen Kältekreis mit einer Auskleidung,
• 2 ein Ausführungsbeispiel für einen adsorptiven Formkörper mit einer Jalousievorrichtung.

The invention will be explained in more detail with reference to two schematic diagrams. Hereby show:

• 1 a cooling circuit with a lining,
• 2 an embodiment of an adsorptive molded body with a shutter device.

1 shows a schematic diagram of a refrigerant circuit 1 with a compressor 2 , a capacitor 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 supply 8th , a heat sink lead 9 and a heat sink connection 10 , The refrigeration circuit 1 is in this example with the flammable working fluid propane, which also under the name R290 is known, operated. Propane is heavier than air, so it sinks in the event of a leak in the refrigerant circuit 1 tends to be in the housing 6 downward. Due to temperature differences in the housing and corresponding convection, leakage-induced propane is also found in the rest Housing interior. This case 6 is therefore complete with the adsorptive lining 11 lined.

2 shows an adsorptive molded body of the type in the housing may have several or should be, these moldings can also completely enclose the housing interior, especially on the bottom, since leaking due to leakage of propane in air drops. Incidentally, such shaped articles also contribute to the reduction of noise emissions.

The exemplary adsorptive molding 12 has in its interior an activated carbon mat 13 consisting of either activated carbon fibers or activated carbon pellets fixed in a permeable matrix. Also honeycombs are possible. On the back there is a load-bearing structure with click fasteners 14 with which the adsorptive shaped body 12 on the inside of the case 6 is fixed. On the opposite side is a permeable retaining grid 15 ,

For assembly and disassembly, the adsorptive molded body has a shutter device 16 on which consists of roles on which simultaneously on the front and back foils pulled up before use and rolled up and pulled down after use and can be closed down. The films on the front and back can also form a bag, which has a pull closure and gas-tightly seals the adsorptive molding before and after use.

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

Adsorptive lining

12

adsorptive shaped body

13

Activated carbon mat

14

Back with click closure

15

holding grid

16

A blind apparatus

17

foil

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• WO 2015/032905 A1 [0008, 0009]
• DE 553295 [0010]
• DE 102011116863 A1 [0011]
• DE 19526980 A1 [0012]
• DE 19525064 C1 [0013]
• EP 3106780 A1 [0014]

Claims (5)

Device for the safe performance of a left-handed thermodynamic Rankine Rank cycle (1) 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, comprising - at least one compressor (2) for Working fluid, - at least one Enspannseinrichtung (4) for working fluid, - at least two heat exchangers (3, 5) for working fluid, each having at least two terminals (7, 8, 9, 10) for heat transfer fluids, - a closed housing (6), - which comprises all devices connected to the closed working fluid circulation, - may comprise further devices, - and is lined with an adsorbent (11) which is able to adsorb working fluid, characterized in that - an adsorbent is used, which is the working fluid and a Inert gas can adsorb, - wherein the A Working fluid has a higher adsorptive binding to the adsorbent than the inert gas, and wherein the adsorbent, with which the housing (6) is lined, is pre-loaded saturated with the inert gas. Device after Claim 1 , characterized in that the adsorbent activated carbon, the working fluid is propane and the inert gas is carbon dioxide. Device according to one of Claims 1 or 2 , characterized in that the lining (11) by adsorbent by means of dimensionally stable mats or molded body (12) is made. Device according to one of Claims 1 to 3 , characterized in that the dimensionally stable mats or moldings (12) have a gas and liquid permeable holding grid (15) and a dimensionally stable rear side structure (14) with a fastening device. Device according to one of Claims 1 to 4 , characterized in that the dimensionally stable mats or molded body (12) have a Venetian blind device (16), with the at least one film (17) can be pulled gas-tight over the dimensionally stable mats or molded body.

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