| JP53132841 | REFRIGERATOR |
| JP2009002610 | REFRIGERATOR AND ENVIRONMENTAL TESTER |
| JP2009002647 | SUPERCOOLING DEVICE |
| CLAIMS 1. A refrigeration apparatus for subcooling the liquid line (11, 111, 211, 311, 411, 511) of a refrigeration system (12, 112, 212, 312, 412, 512), particularly for medium- or low-temperature refrigeration systems and with an installed power of more than 2 kW, characterized in that it comprises — at least one heat exchanger (13) functionally connected to said liquid line (11, 111, 211, 311, 411, 511) in order to subcool its liquid, - at least one satellite compressor (14) for supplying said heat exchanger (13), - at least one electronic device (15) for modulating the power of said satellite compressor (14) as a function of the refrigeration power that is needed to keep the temperature of the liquid in said liquid line (11, 111, 211, 311, 411, 511), in output from said heat exchanger (13), at a predefined value. 2. The refrigeration apparatus according to claim 1, characterized in that said electronic device (15) comprises an inverter for driving the electric motor for the actuation of said satellite compressor (14). 3. The refrigeration apparatus according to claim 1, characterized in that said satellite compressor (14) has a power substantially equal to one tenth of the compression power to be installed in said refrigeration system (12, 112, 212, 312, 412, 512) to obtain a refrigerating effect of cooling to -1O0C. 4. The refrigeration apparatus according to claim 1, characterized in that said electronic device comprises an electronic controller for driving said inverter, which is adapted to drive it to keep the subcooling temperature of said liquid substantially at a predefined value. 5. The refrigeration apparatus according to claim 1, characterized in that it comprises devices for recovering the lubrication oil of the compressors of said refrigeration system, of the gravity type. |
The present invention refers to a refrigeration apparatus for subcooling the liquid line of a refrigeration system, particularly for medium- or low-temperature refrigeration systems and with an installed power of more than 2 kW. Background Art
Nowadays, many refrigeration systems have a compressor, or a battery of compressors, with installed power for meeting the most demanding requirements in terms of refrigeration power.
Therefore, the operation of such compressors is irregular, since they operate until a lower temperature threshold of the environment to be refrigerated is reached, and they remain inactive until an upper temperature threshold of this environment is reached.
Such irregular operation is known to be a drawback to the efficiency of the system as a whole.
The use of systems for subcooling the liquid line of a refrigeration system, to increase its efficiency, is also known nowadays. According to this solution, a refrigeration apparatus is coupled with the refrigeration system by means of a heat exchanger which, powered by the compressor, commonly called a satellite compressor, cools the liquid of the refrigeration system, allowing a better energy efficiency of the system as a whole. However, the satellite compressor also generally operates on an irregular basis.
Indeed, it too is installed with sufficient power for meeting the most demanding refrigeration load conditions required.
Another technique known nowadays, aimed at increasing the efficiency of the refrigeration system, consists in using inverters to drive one or more compressors, thus modulating the power of the compressors depending on the refrigeration power required. Disclosure of the Invention
The aim of the present invention is to devise a refrigeration apparatus for subcooling the liquid line of a refrigeration system that allows a higher level of energy efficiency to be reached than in the systems known today.
Within this aim, an object of the invention is to provide a refrigeration apparatus that makes it possible to supply refrigeration power for subcooling the liquid line of a refrigeration system, commensurate with the refrigeration power that this requires.
A further object of the invention is to provide a refrigeration apparatus that is simple in structure and easy to use, and which can be produced at low costs.
This aim, as well as these and other objects which will become better apparent hereinafter, are achieved by a refrigeration apparatus for subcooling the liquid line of a refrigeration system, particularly for medium- or low-temperature refrigeration systems and with an installed power of more than 2 kW, characterised in that it comprises
- at least one heat exchanger functionally connected to such liquid line for subcooling its liquid,
- at least one satellite compressor for supplying such heat exchanger,
- at least one electronic device for modulating the power of such satellite compressor as a function of the refrigeration power that is needed to keep the temperature of the liquid of such liquid line at a predefined value upon output from such heat exchanger. Brief description of the drawings
Further characteristics and advantages of the invention will become better apparent from the following detailed description of some preferred, but not exclusive, embodiments of the refrigeration apparatus according to the invention, illustrated by way of non-limiting example in the accompanying drawings, in which the figures from 1 to 6 schematically illustrate six configurations of use of a refrigeration apparatus according to the invention, functionally connected to six different corresponding refrigeration systems. Ways of carrying out the Invention
It should be noted that anything found to be already known during the patenting process is understood not to be claimed and to be the subject of a disclaimer.
With reference to the figures, the reference numeral 10 generally designates a refrigeration apparatus for subcooling the liquid line 11 of a refrigeration system 12, particularly for medium- or low-temperature refrigeration systems and with an installed power of more than 2 kW.
According to the invention, the refrigeration apparatus 10 has a particular characteristic in that it comprises - a heat exchanger 13, which is functionally connected to the liquid line 1 1, for subcooling its liquid,
- a satellite compressor 14 for supplying the heat exchanger 13,
- an electronic device 15 for modulating the power of the satellite compressor 14 as a function of the refrigeration power that is needed to keep the temperature of the liquid in the liquid line 11 at a predefined value upon output from the heat exchanger 13.
By medium-temperature refrigeration systems is meant systems which are adapted to generate a refrigerating effect to a temperature that is substantially comprised between -5°C and -20 0 C, and similarly, by low- temperature refrigeration systems is meant systems which are adapted to generate a refrigerating effect to a temperature that is substantially lower than -20 0 C.
Advantageously, the electronic device 15 comprises an inverter for driving the electric motor for the actuation of the satellite compressor 14. In addition, the electronic device comprises an electronic controller, not shown in the accompanying figures, for driving such inverter, which is adapted to drive it to keep the subcooling temperature of such liquid, in the liquid line 11, at the output from the heat exchanger 13, substantially at a predefined value. The satellite compressor 14 preferably has a rated power that is substantially equal to one tenth of the rated compression power to be installed in such refrigeration system 12 to achieve an effect of refrigeration to -1O 0 C.
More specifically, for a low-temperature refrigeration system 12, and therefore as mentioned above with a value of the temperature of expansion, i.e. to the user 16, that is lower than -20 0 C, preferably the refrigeration capacity of the satellite compressor, referring to -10°C/-15°C, is preselected and equal to one tenth of the compression refrigeration capacity of the refrigeration system at -10 0 C.
The value of the power of the satellite compressor 14, thus obtained, leads to a temperature of the liquid in the liquid line 11, in output from the heat exchanger 13, of from -5°C to -10 0 C such as to allow a Refrigeration Energy of the refrigeration system 12 which is higher by a factor of 40% to 45% inclusively, as a function of the condensation temperature, compared to a refrigeration system of the state of the art. Similarly, if the refrigeration system 12 is medium-temperature, and therefore has a value of expansion that is between -5°C and -20 0 C, preferably the refrigeration capacity of the satellite compressor, referring to 0 0 C, is pre-selected and equal to one tenth of the refrigeration system compression refrigeration capacity of -10 0 C. The value of the power of the satellite compressor 14, thus obtained, leads to a temperature of the liquid in the liquid line 11 , in output from the heat exchanger 13, of around +5 0 C, such as to allow a Refrigeration Energy of the refrigeration system 12 which is higher by a factor of 25% to 30% inclusively, as a function of the condensation temperature, compared to a refrigeration system of the state of the art. In addition, conveniently, the devices for recovering the lubrication oil of the compressors of such refrigeration system are of the gravity type.
With reference to Figure 1, in a first configuration of use of the invention, the refrigeration apparatus 10 has a single satellite compressor 14 driven by such electronic device 15.
The heat exchanger 13 is functionally connected with the liquid line 11 of a refrigeration system 12, the compression power of which is supplied by a main compressor 17 driven by an electronic inverter device 18.
With reference to Figure 2, in a second configuration of use of the invention, the refrigeration apparatus 10 has a single satellite compressor 14 driven by such electronic device 15.
The heat exchanger 13 is functionally connected with the liquid line
111 of a refrigeration system 112, consisting of a refrigeration facility, the compression power of which is supplied by a main compressor 117 which can be modulated and is driven by an electronic inverter device 118, and a main compressor with a fixed power level 119.
With reference to Figure 3, in a third configuration of use of the invention, the refrigeration apparatus 10 has a single satellite compressor 14 driven by such electronic device 15. Depending on application requirements, it is possible to have two satellite compressors each driven by an electronic device for modulation as mentioned above.
The heat exchanger 13 is functionally connected with the liquid line 211 of a refrigeration system 212, consisting of a refrigeration facility, the compression power of which is supplied by two main compressors 217, each driven by an electronic inverter device 218.
With reference to Figure 4, in a fourth configuration of use of the invention, the refrigeration apparatus 10 has a single satellite compressor 14 driven by such electronic device 15. The heat exchanger 13 is functionally connected with the liquid line 311 of a refrigeration system 312, consisting of a refrigeration facility, the compression power of which is supplied by three compressors with fixed power levels 317, which may be installed, depending on requirements, with equal power levels or with different power levels. With reference to Figure 5, in a fifth configuration of use of the invention, the refrigeration apparatus 100, according to the invention, has two satellite compressors 14 each driven by an electronic device 15.
Depending on application requirements, it is possible to have as many as four satellite compressors each driven by an electronic device for modulation as mentioned above.
The heat exchanger 13 is functionally connected with the liquid line
411 of a refrigeration system 412, consisting of a refrigeration facility, the compression power of which is supplied by four compressors with fixed power levels 417, preferably with different and proportional power levels and each equipped with a corresponding inverter 418 that drives it.
With reference to Figure 6, in a sixth configuration of use of the invention, the refrigeration apparatus 10 has a single satellite compressor 14 driven by such electronic device 15.
The heat exchanger 13 is functionally connected with the liquid line 411 of a refrigeration system 412, consisting of a refrigeration facility, the compression power of which is supplied by two compressors with fixed power levels 317.
The operation of a refrigeration apparatus, according to the invention, is as follows. Depending on the operational load of the refrigeration system, 12, 112,
212, 312, 412 or 512, the satellite compressor 14 is driven by the inverter which is driven by the electronic controller, of the electronic device 15, in such a way as to supply refrigeration power to the heat exchanger 13 such as to keep the liquid in the liquid line 11, 111, 211, 311, 411 or 511 substantially equal to a predefined value. In practice it has been found that the invention achieves the intended aim and objects, by providing a refrigeration apparatus for subcooling the liquid line of a refrigeration system that allows a higher level of energy efficiency to be reached than in the systems known today, owing to the modulation of the power of the satellite compressor caused by the inverter that drives it.
In addition, a refrigeration apparatus, according to the invention, makes it possible to supply refrigeration power for subcooling the liquid line of a refrigeration system, commensurate with the refrigeration power that this requires.
The invention, thus conceived, is susceptible of numerous modifications and variations, all of which are within the scope of the appended claims; in addition, all the details may be replaced by other technically equivalent elements. In practice the materials employed, as well as the contingent dimensions and shapes, may be any according to requirements and to the state of the art. The disclosures in Italian Patent Application No. PD2009A000036 from which this application claims priority are incorporated herein by reference. Where technical features mentioned in any claim are followed by reference signs, such reference signs have been inserted for the sole purpose of increasing the intelligibility of the claims and accordingly such reference signs do not have any limiting effect on the interpretation of each element identified by way of example by such reference signs.