EP2233866A1 - A refrigerating plant comprising a plate-type flooded evaporator - Google Patents
A refrigerating plant comprising a plate-type flooded evaporator Download PDFInfo
- Publication number
- EP2233866A1 EP2233866A1 EP10157976A EP10157976A EP2233866A1 EP 2233866 A1 EP2233866 A1 EP 2233866A1 EP 10157976 A EP10157976 A EP 10157976A EP 10157976 A EP10157976 A EP 10157976A EP 2233866 A1 EP2233866 A1 EP 2233866A1
- Authority
- EP
- European Patent Office
- Prior art keywords
- refrigerating plant
- expansion valve
- refrigeration liquid
- thermal expansion
- evaporator
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Withdrawn
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Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
- F25B40/00—Subcoolers, desuperheaters or superheaters
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
- F25B2400/00—General features or devices for refrigeration machines, plants or systems, combined heating and refrigeration systems or heat-pump systems, i.e. not limited to a particular subgroup of F25B
- F25B2400/05—Compression system with heat exchange between particular parts of the system
- F25B2400/053—Compression system with heat exchange between particular parts of the system between the storage receiver and another part of the system
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
- F25B2400/00—General features or devices for refrigeration machines, plants or systems, combined heating and refrigeration systems or heat-pump systems, i.e. not limited to a particular subgroup of F25B
- F25B2400/16—Receivers
Definitions
- the present invention relates to a refrigerating plant comprising a plate-type flooded evaporator.
- Evaporators are known as "flooded" evaporators when the exchange surface is completely covered with refrigeration liquid.
- a phase separator is normally used downstream of the evaporator to receive the biphasic mixture coming from the evaporator and the condensed liquid supplied by the thermal expansion valve. The biphasic mixture is separated in the separator due to the force of gravity and the liquid phase is recirculated in the evaporator with the condensed liquid that flows through the valve, while the vapour is drawn out by the compressor.
- flooded evaporators require a condensate expansion valve to guarantee a constant level of liquid in the separator.
- flooded evaporators can be smaller than dry evaporators in that an area of the surface is not used for overheating, but they need more refrigeration liquid.
- flooded evaporators the evaporating fluid and that to be cooled usually flow in the same direction, so that the maximum differences in temperature correspond with the low heat exchange coefficients of the fluid in the liquid phase with low vapour concentrations.
- the main characteristic of flooded evaporators is that they allow small differences in temperature between the evaporating fluid and the fluid to be cooled so that, with the same output temperature of the fluid to be cooled, the evaporator achieves higher vaporization temperatures and thus a higher performance coefficient.
- the degree of sensitivity with which the temperature is measured would produce an "oscillatory" phenomenon corresponding with an opening and closing phase of the flow of the refrigeration liquid controlled by the thermal expansion valve and thus result in sudden and exaggerated reactions of the plant to external stress factors.
- the behaviour of the thermal expansion valve affects the action of the regenerative exchanger creating a vicious cycle both in the case of low overheating and in the case of high overheating causing the aforesaid oscillation.
- the object of the present invention is to provide a refrigerating plant comprising a plate-type flooded evaporator that overcomes the problems typical of the prior art solutions.
- the object of the present invention is a refrigerating plant the essential characteristics of which are claimed in Claim 1, and the preferred and/or secondary characteristics are claimed in Claims 2-5.
- figure 1 designated as a whole by number 1 is a refrigerating plant with some parts removed for the sake of simplicity.
- the plant 1 comprises a plate-type flooded evaporator 2, a compressor 3, a condenser 4, a regenerative exchanger 5 and a thermostatic vale 6 of the self-adjusting mechanical type.
- the purpose of the thermostatic valve 6 is to guarantee a constant level of liquid in said evaporator 2.
- the thermostatic valve 6 receives the warm refrigeration liquid from the regenerative exchanger 5 which, in turn, receives it from the condenser 4.
- the regenerative exchanger 5 also receives the biphasic liquid/vapour mixture coming from the evaporator 2 and having a vapour concentration of approx. 0.95. Inside the regenerative exchanger 5 the mixture coming from the evaporator 2 evaporates completely and the resulting vapour is carried into the compressor 3 to continue the refrigeration cycle. A temperature and pressure sensor 7 is arranged to read the temperature and pressure of the vapour leaving the regenerative exchanger 5.
- the vaporization phase inside the regenerative exchanger 5 takes place by means of a high thermal inertia of the condensed refrigeration liquid independent of the operation of the thermostatic valve 6. Said effect is obtained by means of a regenerative exchanger comprising a flow path of the biphasic mixture to be vaporized immersed in a volume of pressure-condensed refrigeration liquid.
- the ratio in volume of the flow path of the biphasic mixture to be vaporized and the volume of the condensed refrigeration liquid is such to guarantee said high thermal inertia.
- the above flow path consists of a spiral tube 8 arranged with its axis in a horizontal or vertical position and immersed in a cylindrical tank 9 full of pressure-condensed refrigeration liquid.
- figure 2 designated as a whole by number 11 is a refrigerating plant with some parts removed for the sake of simplicity.
- the parts identical to those of the plant 1 in figure 1 are indicated by the same numbers and not described again.
- the plant 11 differs from the plant 1 due to the presence of a microprocessor 12 capable of guaranteeing the electronic control of overheating by the management of the software of an electric expansion-type valve 13.
Landscapes
- Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- Mechanical Engineering (AREA)
- Thermal Sciences (AREA)
- General Engineering & Computer Science (AREA)
- Devices That Are Associated With Refrigeration Equipment (AREA)
- Filling Or Discharging Of Gas Storage Vessels (AREA)
- Sorption Type Refrigeration Machines (AREA)
- Heat-Exchange Devices With Radiators And Conduit Assemblies (AREA)
Abstract
A refrigerating plant (1; 11) comprising a flooded evaporator (2), a compressor (3), a condenser (4) and a thermal expansion valve (6). The flooded evaporator (2) is of the plate type and the regenerative exchanger (5) is connected to the evaporator through the thermal expansion valve (6; 13) for letting the refrigeration liquid through and for receiving the refrigeration liquid coming from the condenser (4). In the regenerative exchanger (5) there taking place a vaporization step of the biphasic mixture coming from the flooded evaporator (2) by means of a high thermal inertia of the condensed refrigeration liquid.
Description
- The present invention relates to a refrigerating plant comprising a plate-type flooded evaporator.
- Evaporators are known as "flooded" evaporators when the exchange surface is completely covered with refrigeration liquid. A phase separator is normally used downstream of the evaporator to receive the biphasic mixture coming from the evaporator and the condensed liquid supplied by the thermal expansion valve. The biphasic mixture is separated in the separator due to the force of gravity and the liquid phase is recirculated in the evaporator with the condensed liquid that flows through the valve, while the vapour is drawn out by the compressor.
- The uniform distribution of the fluid in the ducts flowing into the evaporator is helped by the fact that it is a liquid rather than a low mass fraction biphasic mixture, thus avoiding the possibility of some ducts being supplied with vapour only, which would result in a drastic reduction in heat exchange.
- Due to the particular way in which they work, flooded evaporators require a condensate expansion valve to guarantee a constant level of liquid in the separator.
- In particular, flooded evaporators can be smaller than dry evaporators in that an area of the surface is not used for overheating, but they need more refrigeration liquid.
- Moreover, in flooded evaporators the evaporating fluid and that to be cooled usually flow in the same direction, so that the maximum differences in temperature correspond with the low heat exchange coefficients of the fluid in the liquid phase with low vapour concentrations. The main characteristic of flooded evaporators is that they allow small differences in temperature between the evaporating fluid and the fluid to be cooled so that, with the same output temperature of the fluid to be cooled, the evaporator achieves higher vaporization temperatures and thus a higher performance coefficient.
- Despite the advantages of flooded evaporators over dry evaporators, plate-type flooded evaporators are difficult to use in refrigerating plants.
- With a plate-type flooded evaporator in a refrigerating plant comprising a traditional regenerative exchanger, for instance a tube-in-tube or spiral heat exchanger, the degree of sensitivity with which the temperature is measured would produce an "oscillatory" phenomenon corresponding with an opening and closing phase of the flow of the refrigeration liquid controlled by the thermal expansion valve and thus result in sudden and exaggerated reactions of the plant to external stress factors. In other words, the behaviour of the thermal expansion valve affects the action of the regenerative exchanger creating a vicious cycle both in the case of low overheating and in the case of high overheating causing the aforesaid oscillation.
- The object of the present invention is to provide a refrigerating plant comprising a plate-type flooded evaporator that overcomes the problems typical of the prior art solutions.
- The object of the present invention is a refrigerating plant the essential characteristics of which are claimed in Claim 1, and the preferred and/or secondary characteristics are claimed in Claims 2-5.
- In order to better understand the present invention, some non-limiting embodiments thereof will now be described by way of example with the help of the figures in the accompanying drawing, in which:
-
figure 1 is a schematic illustration of a refrigerating plant according to the present invention; and -
figure 2 is a schematic illustration of another refrigerating plant according to the present invention. - In
figure 1 designated as a whole by number 1 is a refrigerating plant with some parts removed for the sake of simplicity. - The plant 1 comprises a plate-type flooded
evaporator 2, acompressor 3, acondenser 4, aregenerative exchanger 5 and athermostatic vale 6 of the self-adjusting mechanical type. - As the
evaporator 2 is of the flooded type, the purpose of thethermostatic valve 6 is to guarantee a constant level of liquid in saidevaporator 2. - The
thermostatic valve 6 receives the warm refrigeration liquid from theregenerative exchanger 5 which, in turn, receives it from thecondenser 4. - In particular, as well as receiving the warm refrigeration liquid coming from the
condenser 4, theregenerative exchanger 5 also receives the biphasic liquid/vapour mixture coming from theevaporator 2 and having a vapour concentration of approx. 0.95. Inside theregenerative exchanger 5 the mixture coming from theevaporator 2 evaporates completely and the resulting vapour is carried into thecompressor 3 to continue the refrigeration cycle. A temperature andpressure sensor 7 is arranged to read the temperature and pressure of the vapour leaving theregenerative exchanger 5. - The vaporization phase inside the
regenerative exchanger 5 according to the present invention takes place by means of a high thermal inertia of the condensed refrigeration liquid independent of the operation of thethermostatic valve 6. Said effect is obtained by means of a regenerative exchanger comprising a flow path of the biphasic mixture to be vaporized immersed in a volume of pressure-condensed refrigeration liquid. The ratio in volume of the flow path of the biphasic mixture to be vaporized and the volume of the condensed refrigeration liquid is such to guarantee said high thermal inertia. In particular, the above flow path consists of aspiral tube 8 arranged with its axis in a horizontal or vertical position and immersed in acylindrical tank 9 full of pressure-condensed refrigeration liquid. - In
figure 2 designated as a whole bynumber 11 is a refrigerating plant with some parts removed for the sake of simplicity. The parts identical to those of the plant 1 infigure 1 are indicated by the same numbers and not described again. - In the specific case, the
plant 11 differs from the plant 1 due to the presence of amicroprocessor 12 capable of guaranteeing the electronic control of overheating by the management of the software of an electric expansion-type valve 13. - It will be apparent to the person skilled in the art that with the plant according to the present invention overheating can be controlled by means of the thermostatic valve without the oscillatory phenomenon typical of plants using a traditional regenerative exchanger. The mass of warm refrigeration liquid ensures considerable stability in relation to the exchange of heat between the biphasic mixture to be evaporated and said warm refrigeration liquid.
Claims (5)
- Refrigerating plant (1; 11) comprising a flooded evaporator (2), a compressor (3), a condenser (4) and a thermal expansion valve (6); said refrigerating plant being characterized in that said flooded evaporator (2) is of the plate type and in that it comprises a regenerative exchanger (5), connected to said evaporator through said thermal expansion valve (6; 13) for letting the refrigeration liquid through and for receiving the refrigeration liquid coming from the condenser (4); there taking place in said regenerative exchanger (5) a vaporization step of the biphasic mixture coming from said flooded evaporator (2) by means of a high thermal inertia of the condensed refrigeration liquid.
- Refrigerating plant (1; 11) according to Claim 1, characterized in that said regenerative exchanger comprises a flow path of the biphasic mixture to be vaporized immersed in a volume of pressure-condensed refrigeration liquid.
- Refrigerating plant (1; 11) according to Claim 2, characterized in that the flow path is a spiral tube (8), whose axis is horizontally or vertically arranged, and which is immersed in a cylindrical reservoir (9) full of pressure-condensed refrigeration liquid.
- Refrigerating plant (1) according to any one of the preceding Claims, characterized in that said thermal expansion valve (6) is a self-adjusting mechanical thermostatic expansion valve.
- Refrigerating plant (11) according to any one of Claims 1-3, characterized in that it comprises a microprocessor (12) to guarantee the electronic control of overheating by the management of the thermal expansion valve (13) software; said thermal expansion valve (13) being of the modulating type with electrical control.
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
IT000195A ITBO20090195A1 (en) | 2009-03-27 | 2009-03-27 | REFRIGERANT SYSTEM INCLUDING AN EVAPORATED PLATE EVAPORATOR |
Publications (1)
Publication Number | Publication Date |
---|---|
EP2233866A1 true EP2233866A1 (en) | 2010-09-29 |
Family
ID=41228446
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP10157976A Withdrawn EP2233866A1 (en) | 2009-03-27 | 2010-03-26 | A refrigerating plant comprising a plate-type flooded evaporator |
Country Status (2)
Country | Link |
---|---|
EP (1) | EP2233866A1 (en) |
IT (1) | ITBO20090195A1 (en) |
Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US2116100A (en) * | 1935-08-09 | 1938-05-03 | U D Engineering Company Ltd | Refrigerating apparatus |
US2892320A (en) * | 1955-05-31 | 1959-06-30 | Lester K Quick | Liquid level control in refrigeration system |
JPH11248294A (en) * | 1998-02-27 | 1999-09-14 | Showa Alum Corp | Refrigerating machine |
JP2000205706A (en) * | 1999-01-12 | 2000-07-28 | Zexel Corp | Refrigerating device |
JP2004069142A (en) * | 2002-08-05 | 2004-03-04 | Japan Climate Systems Corp | Receiver tank and vehicle air-conditioner equipped with the receiver tank |
-
2009
- 2009-03-27 IT IT000195A patent/ITBO20090195A1/en unknown
-
2010
- 2010-03-26 EP EP10157976A patent/EP2233866A1/en not_active Withdrawn
Patent Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US2116100A (en) * | 1935-08-09 | 1938-05-03 | U D Engineering Company Ltd | Refrigerating apparatus |
US2892320A (en) * | 1955-05-31 | 1959-06-30 | Lester K Quick | Liquid level control in refrigeration system |
JPH11248294A (en) * | 1998-02-27 | 1999-09-14 | Showa Alum Corp | Refrigerating machine |
JP2000205706A (en) * | 1999-01-12 | 2000-07-28 | Zexel Corp | Refrigerating device |
JP2004069142A (en) * | 2002-08-05 | 2004-03-04 | Japan Climate Systems Corp | Receiver tank and vehicle air-conditioner equipped with the receiver tank |
Also Published As
Publication number | Publication date |
---|---|
ITBO20090195A1 (en) | 2010-09-28 |
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Effective date: 20110330 |