U.S. patent application number 14/425635 was filed with the patent office on 2015-08-20 for collecting reservoir and method for recovering working medium in sorption devices.
The applicant listed for this patent is INVENSOR GMBH. Invention is credited to Niels Braunschweig, Eythymios Kontogeorgopoulos, Soeren Paulussen.
Application Number | 20150233620 14/425635 |
Document ID | / |
Family ID | 49150959 |
Filed Date | 2015-08-20 |
United States Patent
Application |
20150233620 |
Kind Code |
A1 |
Braunschweig; Niels ; et
al. |
August 20, 2015 |
COLLECTING RESERVOIR AND METHOD FOR RECOVERING WORKING MEDIUM IN
SORPTION DEVICES
Abstract
The invention relates to a sorption device, wherein working
medium that escapes when inert gas flows out is collected in a
collecting reservoir (1), and wherein said working medium can be
returned from the collecting reservoir to a part of the sorption
device that is different from the collecting reservoir. The
invention further relates to a method for recovering working medium
and the use of a collecting reservoir to collect working medium and
return working medium to a sorption process.
Inventors: |
Braunschweig; Niels;
(Berlin, DE) ; Paulussen; Soeren; (Berlin, DE)
; Kontogeorgopoulos; Eythymios; (Berlin, DE) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
INVENSOR GMBH |
Berlin |
|
DE |
|
|
Family ID: |
49150959 |
Appl. No.: |
14/425635 |
Filed: |
September 11, 2013 |
PCT Filed: |
September 11, 2013 |
PCT NO: |
PCT/EP2013/068844 |
371 Date: |
March 4, 2015 |
Current U.S.
Class: |
62/85 ;
62/475 |
Current CPC
Class: |
F25B 43/046
20130101 |
International
Class: |
F25B 43/04 20060101
F25B043/04 |
Foreign Application Data
Date |
Code |
Application Number |
Sep 11, 2012 |
DE |
102012108465.3 |
Claims
1. A sorption device comprising at least one collecting reservoir,
a condenser, a desorber and a working medium, wherein the at least
one collecting reservoir is directly or indirectly connected to the
condenser, and wherein at least one throttle element is provided
between the collecting reservoir and the condenser, wherein the
sorption device is configured so that working medium that escapes
during the flowing out of inert gas is collected in the collecting
reservoir, and said working medium can be returned from the
collecting reservoir into a part of the sorption device that is
different from the collecting reservoir.
2. The sorption device as claimed in claim 1, wherein the sorption
device moreover comprises an inert gas trap and the collecting
reservoir is connected to the condenser via said inert gas
trap.
3. The sorption device as claimed in claim 2, wherein a first
throttle element is provided between the inert gas trap and the
collecting reservoir and a second throttle element is provided
between the condenser and the inert gas trap.
4. The sorption device as claimed in claim 1, wherein the
collecting reservoir comprises internal baffle plates.
5. The sorption device as claimed in claim 1, wherein the sorption
device is an adsorption device.
6. The sorption device as claimed in claim 1, wherein the
collecting reservoir has at least one opening.
7. The sorption device as claimed in claim 1, wherein the sorption
device comprises a plurality of collecting reservoirs arranged in a
row.
8. The sorption device as claimed in claim 1, wherein the
collecting reservoir is made from metal and/or plastic.
9. The sorption device as claimed in claim 1, wherein the
collecting reservoir comprises a coolant source and/or cooling
fins.
10. A method for recovering working medium in a sorption process of
a sorption device as claimed in claim 1, wherein exited working
medium that has escaped during the removal of inert gases is
collected in the collecting reservoir and is returned from the
collecting reservoir into a part of the sorption device that is
different from the collecting reservoir.
11. The method as claimed in claim 10, comprising the following
steps: a. introducing a vaporous working medium from the desorber
into the condenser, wherein the working medium at least partially
condenses in the condenser and the inert gas collects in the
condenser, b. increasing pressure in the condenser, c. opening a
throttle element provided between the condenser and the collecting
reservoir, wherein the inert gas and the working medium flow from
the condenser into the collecting reservoir, d. collecting the
working medium in the collecting reservoir, and e. returning the
working medium into a part of the sorption device that is different
from the collecting reservoir.
12. The method as claimed in claim 10, wherein the collecting
reservoir is connected to the condenser via an inert gas trap, and
wherein the method comprises: (i) cooling the inert gas trap using
a cooling element to a temperature that is lower, the same or
similar to that of the condenser, (ii) introducing a vaporous
working medium from the desorber or a desorber unit into the
condenser, wherein the working medium at least partially condenses
in the condenser and the inert gas collects in the condenser, (iii)
opening a throttle element provided between the condenser and the
inert gas trap, wherein the inert gas and vaporous working medium
flow from the condenser into the inert gas trap, (iv) heating the
inert gas trap, (v) opening a throttle element provided between the
inert gas trap and the collecting reservoir, through which the
inert gas and the working medium flow out from the inert gas trap
into the collecting reservoir, (vi) collecting the working medium
in the collecting reservoir, and (vii) returning the working medium
into a part of the sorption device that is different from the
collecting reservoir.
13. A method for collecting and returning working medium in a
sorption process, wherein the collecting reservoir is attached to a
sorption unit and wherein the working medium flows, during the
removal of inert gas from a sorption unit, into a collecting
reservoir, and wherein the working medium that flowed out is
returned into the sorption unit.
14. The method of claim 13, wherein the working medium is returned
in a liquid form.
15. The method of claim 13, wherein the working medium condenses in
the collecting reservoir.
16. The method of claim 13, wherein the collecting reservoir is
connected to an inert gas trap of the sorption unit.
17. The method of claim 13, wherein the working medium is sucked
back by vacuum pressure.
18. The method of claim 5, wherein the sorption device is an
adsorption cooling machine.
19. The method of claim 11, wherein the pressure in the condenser
is increased by heating.
Description
PRIOR ART
[0001] Sorption devices, in particular sorption cooling machines,
are known from the prior art.
[0002] Materials and substances present in a sorption system can
outgas or can for example release gases as a result of a chemical
conversion. These disturbing gases or vapours prevent a rapid
sorption process because they make the access of the vaporous
working medium to the sorption medium difficult during adsorption
or absorption, and prevent or make difficult the access of the
vaporous working medium to the condensation surfaces during
desorption, both of which result in an extreme slowing down of the
heating and/or refrigeration process. The consequence is a
substantial drop in performance of these sorption systems. What is
referred to here as disturbing gases are generally substances that
influence the access of the working medium vapours to the sorption
medium and thus impede the sorption process (for example carbon
dioxide, nitrogen etc.). The gases are also referred to as inert
gases or foreign gases. These substances may be pre-sorbed in the
sorption medium, released as a result of a chemical reaction,
degassed from the available housing materials or enter via leaks in
the system. In summary, this means that in such vacuum sorption
devices there is in principle the problem that either outgassing or
leaks can lead to an increase in pressure and thus to a degradation
of the function of the device.
[0003] The prior art describes various means for removing the inert
gases from the system of the sorption machine. For example, DE 44
252 B4 discloses a method wherein a binding agent is introduced
into the sorption machine. In order to keep the system free of
disturbing inert gas or vapour for the sorption process, so that
only working medium vapour is present during the vapour phase, a
binding agent is added to the sorption system. This binding agent
has here the task of binding any inert gases or vapours present or
released in the sorption system and thus to extract them from the
working medium vapour space. In doing so, it has to be capable of
binding as much inert gas or vapour as is released in the sorption
system by degassing or a chemical reaction of the substances and
materials contained therein. Therefore, in a hermetically sealed
sorption system, only a limited amount of inert gas or vapour can
occur, and this is usually at the beginning of the sorption cycles.
Within this period of time, the binding agent only needs to bind
this particular amount of inert gas. Suitable as binding agents are
in principle any substances that are capable of binding the inert
gases or vapours occurring in a sorption system. However, the
binding agent should be able not to release the bound inert gas
even in the case of system-related temperature fluctuations. Since
most binding agents have a tendency to do so at high temperatures,
the binding agent should be positioned at a location where
temperatures as low as possible and only minor temperature
fluctuations prevail. In a sorption system, the highest
temperatures occur in the sorption agent container during sorption
as well as during desorption. According to DE 44 44 252 B4, the
binding agent is placed in a region where the comparatively lower
system temperatures are present, e.g. in the condenser, the
evaporator or in the collecting reservoir.
[0004] Further, DE 103 10 748 B3 describes a method for removing
inert gases from a sorption machine. In this context, an
intermediate phase is provided in which, once foreign gases have
been detected in the system (for example as a result of an increase
in the internal pressure or as a result of an insufficient
condenser performance), a process is started which removes these
disturbing gases from the vacuum system. Initially, the heat
dissipation from the condenser is prevented as completely as
possible. Thereafter, heat is for example supplied to the sorber
via a burner. The working medium (preferably water), which is
driven out of the sorption agent in the form of vapour, initially
condenses at the coldest location in the vacuum space and
continuously heats the complete vacuum space, which during normal
operation is under a vacuum. In the course of this, the pressure
rises in the system. If the system pressure exceeds the ambient
pressure (as a rule an ambient pressure of 1013 mbar, but other
constellations are also possible), a discharge unit (for example
and preferably a valve) opens and allows the vaporous content to
flow out into the ambient atmosphere. In a fashion, the vapour
coming from the sorber therefore gradually "pushes" the foreign
gases out. In the course of this, also part of the working medium
normally gets lost. Once all the foreign gases have been removed
from the system, the discharge unit is closed.
[0005] EP 2 357 433 discloses a device that is connected to a
sorption machine. Here, a cavity for buffering inert gas is
connected in the region of the liquefier. The cavity has an inlet
valve in the lower region thereof, and the inlet valve is always
covered, on the cavity side, with liquid working medium.
[0006] The prior art also discloses a process of removing inert
gas, wherein the inert gas collects in the condenser of a sorption
machine, in particular an adsorption machine or in a separate
device (inert gas collection device). An inert gas collection
device is also referred to as an inert gas trap or an inert gas
collection device. This device having inert gas and working medium
is heated up to overpressure, and subsequently water vapour and
inert gas are blown off into the environment.
[0007] U.S. Pat. No. 3,555,849A describes an absorption machine,
wherein non-condensable gases are regularly removed from the
system. This document deals with the problem that working medium
gets lost as a result of the process of inert gas removal. It is
proposed to remove the inert gas via an adsorption process and to
expel it only after that. This is supposed to prevent larger
amounts of working medium from flowing out with it.
[0008] Similar solutions are proposed in U.S. Pat. No. 3,592,017A,
U.S. Pat. No. 5,806,322A and U.S. Pat. No. 5,209,074A.
[0009] The inert gas removal devices from the prior art have
several disadvantages. Thus, the water vapour has to be blown off
in a controlled manner, and therefore moisture also collects in the
system. As a result of this repeated process, the sorption cold
machine gradually loses coolant (in particular water). DE 103 10748
describes devices, but this problem is completely ignored. Here, an
amount of working medium (e.g. coolant) that corresponds to the
size of the system and is geared to the lifetime of the system is
provided during the production of the device. However, this
increases the costs of the system and moreover leads to
difficulties if the system is supposed to be operated longer than
originally planned.
[0010] Accordingly, it is the object of the present invention to
provide a device and a method for preventing loss of working medium
and for overcoming the problems encountered in the prior art.
DESCRIPTION OF THE INVENTION
[0011] This object is achieved by means of the independent claims.
Advantageous embodiments can be seen from the dependent claims.
[0012] In a first preferred embodiment, the invention relates to a
sorption device, comprising at least one collecting reservoir, a
condenser, a desorber and a working medium, wherein the collecting
reservoir is directly or indirectly connected to the condenser and
wherein at least one throttle element is provided between the
collecting reservoir and the condenser, wherein working medium is
collected in the collecting reservoir, which escapes when inert gas
flows out, and wherein this working medium can be returned from the
collecting reservoir into part of the sorption device that is
different from the collecting reservoir.
[0013] The wording "into part of the sorption device that is
different from the collecting reservoir" is meant to refer to the
fact that the working medium is discharged from the collecting
reservoir, however without leaving the sorption device.
[0014] Inert gas can here also be referred to as foreign gas.
[0015] A person skilled in the art knows which further components
are contained in the sorption device. Preferably, an evaporator is
also included. Moreover, an adsorber or an absorber is preferably
included. Instead of the adsorber, however, the desorber may also
be implemented as an adsorber-desorber unit. In terms of the
invention, therefore, a desorber may also act as an
adsorber-desorber.
[0016] In terms of the invention, the condenser may also be a
combined evaporator/condenser unit.
[0017] The invention is based on a general rethinking. Conventional
sorption devices or sorption units are systems that are sealed as
far as possible or are hermetically sealed. So far, experts have
normally been trying not to allow any return flow into such a
vacuum system. This is also evident from the solution approaches
made so far, because the attempts so far made in the prior art have
been directed to freeing the inert gas as much as possible from
working medium prior to the latter flowing out. This means that
attempts have been made to keep the outflow of working medium as
low as possible. So far, nobody has thought of returning the
working medium. Therefore, the invention pursues a completely novel
approach. The aim is no longer to control the loss of working
medium itself, but to recover "lost" working medium. The invention
allows the working medium to flow out into a region in which
ambient pressure prevails (namely into a collecting reservoir).
Subsequently, the working medium is returned from the area with
ambient pressure back into the vacuum system. Such an approach has
so far neither been disclosed nor suggested in the prior art.
[0018] As a result of this return, the many and complex solution
approaches from the prior art, which address the problem of freeing
the inert gas from working medium, become redundant.
[0019] The collecting reservoir is a simple and low-cost device
that can also be retrospectively fitted to older sorption devices.
In this context it is particularly advantageous if the preferred
collecting reservoir can be disassembled.
[0020] A great advantage of the invention is moreover that the
sorption device can be filled, re-filled and/or evacuated via the
collecting reservoir.
[0021] The collecting reservoir can be installed in any desired way
and at any location, as long as the working medium can be
completely returned.
[0022] The throttle element is preferably selected from the group
comprising valves, straight-way valves, angle valves, Y-type
valves, magnetic valves, check valves and/or float valves. The
throttle element is preferably integrated into a connection means
and effects a local narrowing of the flow cross section.
Advantageously, different valves, which may be classified according
to their geometrical form, may be integrated into a throttle
element. As a result of using a valve, the flow rates in the
connection means can be accurately and precisely dosed by modifying
the nominal diameter and also a secure sealing against the
environment may be provided. The throttle elements can
advantageously be actuated by hand, by a medium, automatically or
electromagnetically.
[0023] It is particularly preferred if the throttle element is
provided between the collecting reservoir and the condenser and is
a valve, a magnetic valve, a slide valve, a check valve, a
capillary tube and/or a membrane.
[0024] It is preferred if the throttle element is provided with a
control between the condenser and the collecting reservoir, which
opens the throttle element as soon as a pressure that is higher
than that in the collecting reservoir occurs in the condenser. If
the throttle element is implemented as a float valve, then the
weight of the float valve has to be sufficiently great to ensure
that an opening, on or against which it rests, is securely sealed.
During the desorption phase, the float valve is lifted by the
working medium vapour flowing into the collecting reservoir. The
float valve may for example be manufactured from plastic, e.g.
polypropylene.
[0025] It is preferred if a connection means connects the condenser
with the collecting reservoir. In this connection it is
particularly preferred if the connection means is at least one tube
or an outlet opening. The tube is preferably connected to the
condenser and the collecting reservoir in an interlocking or bonded
manner. Interlocking connections are preferably achieved by the
interengagement of at least two connection partners. Interlocking
connections comprise screws, rivets, pins or clamps. The tube can
for example be connected to components of the sorption device and
the collecting reservoir by means of screws or rivets and
corresponding seals.
[0026] It is also possible to attach the connection means to the
condenser and the collecting reservoir by bonding means. Bonding
connections are held together by atomic or molecular forces. They
are at the same time non-releasable connections that can be
released only by destruction. Bonded connections comprise
soldering, welding or adhesion.
[0027] In terms of the invention, the working medium can preferably
be a fluid or a coolant. Particularly preferred is the use of water
as a working medium.
[0028] Particularly preferred is the sorption device, which
moreover includes an inert gas trap and the collecting reservoir
can be connected to the condenser via this inert gas trap. However,
it is also preferred that the collecting reservoir is part of the
inert gas trap. This means that the collecting reservoir does not
necessarily have to be a separate component.
[0029] This is the described indirect connection of the collecting
reservoir and the condenser. This indirect connection is preferably
realised by the inert gas trap. Therefore, the collecting reservoir
is connected to the condenser via the inert gas trap. In this
embodiment, at least one described connection means is located
between the collecting reservoir and the inert gas trap and at
least one connection means is located between the condenser and the
inert gas trap.
[0030] The above-described preferred embodiments of throttle
elements and connections are also preferred for this variant of the
invention.
[0031] This embodiment is particularly advantageous because the
advantages of the inert gas trap are combined with the advantages
of the return through the collecting reservoir. As a result of the
inert gas trap, which is preferably an inert gas trap according to
WO 2012/069048, no vacuum pump, binding substance or any noteworthy
use of energy is needed for the evacuation of the foreign gases.
The evacuation of the foreign gases can be carried out during the
ongoing, continuous operation of the sorption device. However, it
may also be advantageous to collect the foreign gases in the inert
gas trap, until a certain overall pressure is present in the
reservoir, and only then to remove the gases from the reservoir. As
a result of the achieved self-evacuation of the machine,
maintenance requirements can be greatly reduced. The disclosure of
WO2012069048 is included in the present application.
[0032] What is also preferred is the sorption device, wherein a
first throttle element is provided between the inert gas trap and
the collecting reservoir and a second throttle element is provided
between the condenser and the inert gas trap. This embodiment is
preferred because both the inflow of the inert gas into the trap
and the outflow into the collecting reservoir can be
controlled.
[0033] What is particularly preferred is if the throttle element
that is provided between the collecting reservoir and the inert gas
trap is a valve, a magnetic valve, a slide valve, a check valve, a
capillary tube and/or a membrane. This embodiment is advantageous
because these throttle elements realise an effective seal.
[0034] It is also preferred that the inert gas trap can be heated.
Thus, by heating the inert gas trap, the pressure inside the trap
is increased. The pressure reached will remain in the vacuum range.
This is advantageous because the amount of air taken in is in
particular a function of the pressure differential between the
sorption device or the inert gas trap and the environment. If the
pressure achieved remains in the vacuum range, the pressure
differential is substantially reduced.
[0035] What is further preferred is the sorption device, with the
collecting reservoir comprising internal baffle plates. This is
particularly advantageous in order to achieve a condensation of
vaporous working media in the collecting reservoir. As a result of
the baffle plates, the vapour of the working medium has a long and
indirect path to the outside. In addition, the vapour has to flow
through the already collected liquid. What is also preferred is a
different type of technical means for separating the drops
entrained in the flow. A person skilled in the art will know other
possibilities for separating drops from the vapour, without
themselves exercising inventive skill.
[0036] In terms of the invention, a sorption device may be an
adsorption machine, in particular an adsorption cooling machine or
an adsorption heat pump. In terms of the invention, a sorption
device may also be an absorption machine. The problem of inert gas
removal and the associated loss of working medium is a principal
problem of sorption processes. Therefore, the reservoir can
advantageously be used both for adsorption and for absorption
systems. It was completely surprising that the collecting reservoir
can be universally used and can be adapted to different system
configurations. Advantageously, the collecting reservoir can be
used for single-chamber systems, but also for systems with two or
more chambers. Moreover, it can be simply and quickly adapted to
other types of sorption machines. To this end, the machines
substantially don't need any apparatus-related modifications. In
terms of the invention, the system configuration preferably refers
to the configuration of the sorption device, i.e. for example the
internal hydraulic wiring of the components of the sorption device,
the internal coolant-side wiring of the components or the modified
basic structure of the sorption device (i.e. the number of
adsorbers, the operation of the evaporator, of the condenser
etc.).
[0037] The adsorption cooling machine comprises at least an
adsorber and a desorber and/or an adsorber/desorber unit, an
evaporator, a condenser and/or a combined evaporator/condenser
unit, which are accommodated in a common container or in separate
containers, which are then connected to each other via pipes or the
like for the flow of coolant. The advantage of the sorption
machines compared to conventional heat pump technology lies in the
fact that the process of adsorption/desorption is carried out
solely by tempering the sorption agent. Thus, the container of the
adsorption machine can be sealed in a hermetical and gas-tight
manner. The use of for example water as a coolant means that the
adsorption cooling machine preferably operates in the vacuum
range.
[0038] The adsorption taking place in an adsorption machine
describes a physical process, wherein a gaseous working medium,
preferably a coolant (for example water vapour), accumulates on a
solid. The desorption of the coolant, i.e. the release of the
coolant from the solid, in turn requires energy. In an adsorption
cooling machine, the coolant, which at low temperatures and low
pressures takes up heat and at higher temperatures and higher
pressures gives off heat, is selected such that the adsorption or
desorption is accompanied by a change of state of aggregation. As
adsorption agents, the prior art describes substances that have
fine pores and therefore have a very large inner surface.
Advantageous materials are active carbon, zeolites, aluminium oxide
or silica gel, aluminium phosphates, silica aluminium phosphates,
metal silica aluminium phosphates, mesostructure silicates,
organometallic backbones and/or microporous material, comprising
microporous polymers. The adsorption material can advantageously be
applied in different ways, which means by filling, adhesion and/or
crystallisation. By way of these different types of application,
the adsorption machine can be adapted to various requirements.
Thus, the machine can be adapted to its location or to the coolant.
Moreover, the layer thickness of the adsorption material is a
crucial factor for the performance of the adsorption machine.
[0039] The collecting reservoir is preferably made from metal
and/or plastic. It has been found that as a result of this, a
low-cost collecting reservoir for collecting working medium can be
provided, which can also withstand high and fluctuating pressures
and temperatures.
[0040] The collecting reservoir can here be connected to an
existing sorption unit. The collecting reservoir will preferably be
connected to an inert gas trap (also referred to as a trap).
However, the collecting reservoir may also be part of the sorption
device or of a vacuum, wherein this part is divided off for example
by a partition.
[0041] The size of the collecting reservoir is not crucial for its
function and only determines the frequency of the emptying
process.
[0042] The shape of the collecting reservoir is preferably selected
such that the working medium (e.g. water) that has flowed in can
completely flow back. For example, a funnel-shaped form is
preferred. It may be advantageous if the container is shaped to be
conical, and experiments have shown that other shapes of the
container are also functional and may therefore be used.
[0043] It is particularly preferred if the collecting reservoir has
an opening. The advantage is that this ensures the pressure to be
balanced with the ambient air. Thus, no positive pressure is
generated if the inert gas with working medium flows into the
collecting reservoir and no vacuum pressure is generated, if the
condensate is sucked or guided back. As a result of the opening,
the pressure in the collecting reservoir will always be maintained
at an ambient pressure level.
[0044] In this connection it is preferred if the opening is kept as
small as possible. In this way it is ensured that the entire
working medium can be returned from the collecting reservoir. This
means that the only working medium losses would be as a result of
the evaporation from the collecting reservoir into the environment.
This is minimised or prevented by providing a correspondingly very
small opening to the environment.
[0045] It is particularly preferred if the working medium is
returned in a liquid form. The vapour of the working medium
advantageously condenses on the inner surface of the collecting
reservoir. In order to support condensation or to enforce it, an
improved discharge of the condensation heat may be prudent.
Advantageously, this is realised as follows: [0046] by cooling fins
(passive cooling, natural convection) and/or [0047] by a fan
(active cooling, forced convection) and/or [0048] by a connection
to a cold source (compression or sorption cooling machine, Peltier
element, but especially also to the evaporator of the sorption
device or by evaporation cooling within the inert gas trap) and/or
[0049] by increasing the thermal mass of the collecting
reservoir.
[0050] Moreover it is preferred that the sorption device comprises
several collecting reservoirs which are disposed one after the
other. Thus, the invention can also be implemented in several
stages, so that a plurality of collecting reservoirs are connected
one after the other or a plurality of inert gas traps are connected
in series or parallel with one or more collecting reservoirs. This
embodiment allows a particularly effective removal of the inert
gases, at the same time with almost complete recovery of the
working medium exiting with it.
[0051] In a further preferred embodiment, the invention relates to
a method for recovering working medium with a sorption process of a
described sorption device, wherein exited working medium, which has
escaped during the removal of inert gases, is collected in a
collecting reservoir and is returned from the collecting reservoir
to a different part of the sorption device.
[0052] It is preferred here if the collecting reservoir is under
ambient pressure. In this way it is ensured that the inert gas can
escape via an opening in the collecting reservoir.
[0053] Preferably, the method comprises the following steps: [0054]
a. introducing a vaporous working medium from the desorber or the
desorber unit into the condenser, wherein the working medium at
least partially condenses in the condenser and the inert gas
collects in the condenser, [0055] b. increasing the pressure in the
condenser, preferably by heating, [0056] c. opening a throttle
element provided between the condenser and the collecting
reservoir, so that inert gas and working medium flow from the
condenser into the collecting reservoir, [0057] d. collecting the
working medium in the collecting reservoir, [0058] e. returning the
working medium into a part of the sorption device that is different
from the collecting reservoir.
[0059] In the prior art, the working medium with the inert gas
would flow out into the environment. The usual objective was to
minimise the loss of working medium, by ensuring that as little
working medium as possible flows out with the inert gas. However,
the invention solves this problem in a different way. Here it is
preferred that working medium flows out, because it is collected in
the collecting reservoir. As long as it is ensured that the working
medium is returned, the system will not lose any working
medium.
[0060] As a result of the heating of the condenser in step b, the
pressure is increased, so that the inert gas can flow out into the
collecting reservoir once the throttle element has been opened.
[0061] If a sorption device with an inert gas trap is used, the
method preferably comprises the following steps: [0062] (i) cooling
the inert gas trap using a cooling element to a temperature that is
lower, the same or similar to that of the condenser, [0063] (ii)
introducing a vaporous working medium from the desorber or the
desorber unit into the condenser, wherein the working medium in the
condenser at least partially condenses and the inert gas collects
in the condenser, [0064] (iii) opening the throttle element
provided between the condenser and the inert gas trap, so that
inert gas and vaporous working medium flow through the condenser
into the inert gas trap, [0065] (iv) heating the inert gas trap,
[0066] (v) opening the throttle element provided between the inert
gas trap and the collecting reservoir, through which throttle
element the inert gas and the working medium flow out from the
inert gas trap into the collecting reservoir, [0067] (vi)
collecting the working medium in the collecting reservoir, [0068]
(vii) returning the working medium into a part of the sorption
device that is different from the collecting reservoir.
[0069] The steps are substantially similar. However, the inert gas
is here initially guided into the inert gas trap. In this trap, the
pressure will then be increased by heating, so that the inert gas
can flow out of the collecting reservoir when the throttle element
is opened.
[0070] Preferably, the working medium is passed from the collecting
reservoir back into the inert gas trap or the condenser. The return
can be carried out by return suction, for example by means of
vacuum pressure.
[0071] In both cases the essential method steps can be depicted as
follows:
[0072] Working medium flows out of the inert gas trap or the
condenser. This working medium flowing out may be present either in
the form of drops or as vapour. These drops or the vapour will be
collected by the collecting reservoir, where the vapour condenses.
After a certain amount of time, the working medium is guided back
into the sorption device. The return preferably takes place when a
certain amount of working medium has been reached in the collecting
reservoir. This can be carried out e.g. in such a way that the
amount of working medium present in the collecting reservoir is
measured or the return is carried out in certain time intervals (or
cycles), which may be synchronised with the operating mode of the
inert gas trap.
[0073] In this collecting reservoir, when the inert gas flows out,
the working medium (preferably coolant, particularly preferably
water) that automatically flows out with it is collected. The
working medium may be collected in the form of drops or vapour, and
this vapour is then condensed in the collecting reservoir. In a
second step, the water is then returned into the sorption
system.
[0074] During the return, it is possible or even very likely that
also air and/or inert gas is sucked or passed into the system,
above all into the condenser or into the inert gas trap. However,
this is not disadvantageous because the inert gas will be
discharged more often than the working medium is returned. For
example, an outflow of inert gas can take place ten times, and
subsequently a return of working medium can take place, so that a
ninefold "net outflow" of inert gas will have taken place.
[0075] In this way, the working medium will be recovered from a
plurality of inert gas removal procedures. The preferred collecting
reservoir is compatible with various sorption machines known from
the prior art and can be universally used. The sucked air can
either be directly removed after the return of the working medium
using the traditional method or may remain in the system and may in
particular gradually be removed together with the newly developing
inert gas. The latter possibility preferably only applies in a case
when the sucked air is minimal and the ratio between removed inert
gas and sucked air is positive.
[0076] The amount of sucked air is in particular a function of the
pressure differential between the part of the sorption device, into
which the working medium is returned (e.g. the condenser or the
inert gas trap) and the ambient air. At room temperature, the
pressure of the inert gas trap will e.g. be approx. 50 mbar,
whereas ambient pressure is 1000 mbar. A pressure differential of
950 mbar will lead to the working medium being sucked out of the
collecting reservoir when the throttle element is opened. However,
in the case of this relatively high pressure differential, a large
amount of air will be sucked as well.
[0077] It is therefore preferred if the part of the sorption
device, into which the working medium is to flow, i.e. for example
the inert gas trap, is heated. However, in this case it has to be
considered that it is advantageous that a certain amount of vacuum
pressure still remains, so that the working medium can be returned
as a result of the vacuum pressure. However, also other return
methods are conceivable.
[0078] It has proved to be particularly advantageous to heat the
part of the sorption device, into which the working medium is
returned, which means for example the inert gas trap, to 50.degree.
C. to 90.degree. C., particularly preferably to 80.degree. C. As a
result, the pressure rises to approx. 900 mbar. This means that the
pressure differential with the ambient pressure will only be
approx. 100 mbar instead of 950 mbar.
[0079] It is particularly preferred if the part of the sorption
device, into which the working medium is returned, which means for
example the inert gas trap or the condenser, is provided with a
pressure sensor. This sensor detects the pressure increase as a
result of the opening of the throttle element. If pressure
compensation has taken place, the working medium has been returned
either completely or almost completely. This embodiment is
particularly advantageous, because it can be ascertained in a
simple manner when the return has been completed.
[0080] In particular, a collecting reservoir or an area of the
inert gas trap for the working medium, in particular the coolant,
is provided, and this is connected to an inert gas trap or the
system of the sorption machine, preferably the adsorption machine
and particularly preferably the adsorption cooling machine.
[0081] In a further preferred embodiment the invention relates to
the use of the described collecting reservoirs for collecting and
returning working medium in a sorption process, wherein the
collecting reservoir is mounted on a sorption unit and wherein the
working medium flows, during the removal of inert gas, from the
sorption unit into the collecting reservoir, and the working medium
flowing out is returned into the sorption unit.
[0082] The term sorption unit preferably refers to a sorption
device without a collecting reservoir. A person skilled in the art
will know which components have to be included in such a sorption
unit in order to be able to carry out a sorption process.
[0083] One advantage of the invention is that the collecting
reservoir can here be connected to an existing sorption unit. The
collecting reservoir is preferably connected to an inert gas
trap.
[0084] The collecting reservoir is a simple and low-cost device,
which can also be retrofitted into older sorption units. It is here
particularly advantageous if the preferred collecting reservoir can
be demounted.
[0085] Particularly preferred is the use of the collecting
reservoir where the collecting reservoir is connected to an
adsorption cooling machine. The use of such sorption devices has
proved to be particularly advantageous, because in this way large
amounts of working medium can be saved.
FIGURES
[0086] The invention will be explained by means of exemplary
figures, however it is not limited thereto, because the embodiment
of the collecting reservoir and of the system has only been shown
in a schematic form. Above all, the figures only show the variants
of a separated collecting reservoir on a separated inert gas trap.
However, one or both elements may also be installed in the sorption
device. Moreover, the figures do not show the entire sorption
device. In the figures:
[0087] FIG. 1 shows a preferred collecting reservoir 1 that is
connected to a throttle element 2;
[0088] FIG. 2 shows a preferred collecting reservoir 1 that is
connected to a condenser 3 via a throttle element 2;
[0089] FIG. 3 shows a preferred collecting reservoir 1 that is
connected to a condenser 3 via an inert gas trap 4. In this
connection, a throttle element 2 is provided between the collecting
reservoir 1 and the inert gas trap 4 and a further throttle element
2 is located between the inert gas trap 4 and the condenser 3.
LIST OF REFERENCE NUMERALS
[0090] 1 Collecting reservoir
[0091] 2 Throttle element
[0092] 3 Condenser
[0093] 4 Inert gas trap
* * * * *