GB2133130A - Process and device for the monitoring and control of the defrosting of an evaporator - Google Patents
Process and device for the monitoring and control of the defrosting of an evaporator Download PDFInfo
- Publication number
- GB2133130A GB2133130A GB08333757A GB8333757A GB2133130A GB 2133130 A GB2133130 A GB 2133130A GB 08333757 A GB08333757 A GB 08333757A GB 8333757 A GB8333757 A GB 8333757A GB 2133130 A GB2133130 A GB 2133130A
- Authority
- GB
- United Kingdom
- Prior art keywords
- evaporator
- fluid
- instant
- difference
- parameter
- 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.)
- Granted
Links
- 238000000034 method Methods 0.000 title claims abstract description 18
- 238000010257 thawing Methods 0.000 title claims abstract description 16
- 238000012544 monitoring process Methods 0.000 title claims abstract description 14
- 238000011144 upstream manufacturing Methods 0.000 claims abstract description 4
- 239000012530 fluid Substances 0.000 claims description 21
- 238000009434 installation Methods 0.000 claims description 13
- 238000005259 measurement Methods 0.000 claims description 10
- 230000008020 evaporation Effects 0.000 claims description 4
- 238000001704 evaporation Methods 0.000 claims description 4
- 230000009466 transformation Effects 0.000 claims description 4
- 230000008030 elimination Effects 0.000 claims description 3
- 238000003379 elimination reaction Methods 0.000 claims description 3
- 230000000977 initiatory effect Effects 0.000 claims 1
- 238000001514 detection method Methods 0.000 description 2
- 230000006870 function Effects 0.000 description 2
- 238000010438 heat treatment Methods 0.000 description 2
- 239000007788 liquid Substances 0.000 description 2
- 239000003638 chemical reducing agent Substances 0.000 description 1
- 239000004020 conductor Substances 0.000 description 1
- 230000001419 dependent effect Effects 0.000 description 1
- 238000005457 optimization Methods 0.000 description 1
- 230000000452 restraining effect Effects 0.000 description 1
- 239000000523 sample Substances 0.000 description 1
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
- F25D—REFRIGERATORS; COLD ROOMS; ICE-BOXES; COOLING OR FREEZING APPARATUS NOT OTHERWISE PROVIDED FOR
- F25D21/00—Defrosting; Preventing frosting; Removing condensed or defrost water
- F25D21/002—Defroster control
- F25D21/006—Defroster control with electronic control circuits
-
- 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
- F25D—REFRIGERATORS; COLD ROOMS; ICE-BOXES; COOLING OR FREEZING APPARATUS NOT OTHERWISE PROVIDED FOR
- F25D21/00—Defrosting; Preventing frosting; Removing condensed or defrost water
- F25D21/02—Detecting the presence of frost or condensate
-
- 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
- F25B2700/00—Sensing or detecting of parameters; Sensors therefor
- F25B2700/21—Temperatures
- F25B2700/2117—Temperatures of an evaporator
- F25B2700/21171—Temperatures of an evaporator of the fluid cooled by the evaporator
- F25B2700/21172—Temperatures of an evaporator of the fluid cooled by the evaporator at the inlet
-
- 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
- F25B2700/00—Sensing or detecting of parameters; Sensors therefor
- F25B2700/21—Temperatures
- F25B2700/2117—Temperatures of an evaporator
- F25B2700/21171—Temperatures of an evaporator of the fluid cooled by the evaporator
- F25B2700/21173—Temperatures of an evaporator of the fluid cooled by the evaporator at the outlet
Landscapes
- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Combustion & Propulsion (AREA)
- Physics & Mathematics (AREA)
- Mechanical Engineering (AREA)
- Thermal Sciences (AREA)
- General Engineering & Computer Science (AREA)
- Defrosting Systems (AREA)
- Air Conditioning Control Device (AREA)
- Sorption Type Refrigeration Machines (AREA)
- Vaporization, Distillation, Condensation, Sublimation, And Cold Traps (AREA)
Abstract
Process and device for the monitoring and control of an evaporator (1) in particular the evaporator of a heat pump according to which is compared, at predetermined instants, the variation between the upstream (9) and downstream (10) temperatures or pressures of the air current crossing the evaporator, defrosting of the evaporator being initiated when said difference exceeds a reference value. <IMAGE>
Description
SPECIFICATION
Process and device for the monitoring and control of an evaporator
Background of the Invention
Field of the Invention
The present invention concerns a process and a device for the monitoring and control of an evaporator with a view to detecting the presence of frost or rime on its surface and to initiate its elimination. It concerns, in particular, the case where the evaporator is that of a heat pump.
Background of the Prior Art
The principle of a heat pump is well known to the man skilled in the art and it is simply appropriate to recall herein that heat pumps using air as a source of cold comprise an evaporator where this air exchanges its calories with a refrigerating fluid circulating inside this evaporator and which, due to this fact, is vaporized. During the utilization of such a heat pump for heating, the air used as source of cold is the air taken from outside the premises to be heated. Under certain conditions, the utilization of this external air can lead to the creation of frost on the evaporator, which in restraining the heat exchange between the two fluids, lowers the yield of the installation and necessitates a defrosting operation.This operation, which necessitates the shut down of the pump, must only be carried out when necessary (or useful) for the optimization of the installation. Devices allowing to detect the presence of frost and initiate the defrosting operation are thus provided in these installations.
These devices are usually constituted by sensors allowing to measure the pressure drop undergone by the air during its passage on the evaporator or to measure the evaporation temperature by direct measurement on the evaporator wall. It is also possible to use temporisation systems that initiate the defrosting at predetermined time intervals.
However, these realizations present the drawback bound to the fact that all the measurements made are absolute measurements that take into account neither the initial conditions of the operating conditions nor the external conditions and their variations. Among the external conditions influential on the appearance of frost, can be cited the hygrometric degree of the air and its temperature. Among the conditions of the installation, it is necessary to monitor the air flow rate that, if it is fixed for an installation, and can be consider as constant, varies from one installation to another. All these conditions thus necessitate an adjustment on site of the installation.
Brief Description of the Invention
On the contrary, the present invention foresees a device and a process for detecting the presence of frost that allows to overcome these drawbacks and of which the operation is not dependent on the variations of the'different parameters mentioned herein-above and which does not necessitate any adjustment bound to the site where the evaporator is installed.
In order to do this, the invention foresees a monitoring and control process of an evaporator with a view to ensuring the detection and the elimination of the frost on the surface of the evaporator, the said evaporator being associated to a circulation circuit of a refrigerating fluid and in contact with a second fluid, set in motion in such a way as to through cross it, the second fluid being capable of yielding its calories to the first fluid and of provoking its evaporation, which monitoring and control process consists in measuring a parameter P 1 representative of the state of the second liquid upstream from the evaporator and a parameter P2 representing the state of same liquid downstream from the evaporator, these measures being carried out at instants t determined from an initial instant, in calculating for each instant t,, the difference APi existing between the two parameters P 1 and P2 and in comparing each difference AP, with the difference APO measured at the initial instant, this comparison being made in the form of a subtraction of which the result is a parameter 8, and in controlling the defrosting of the evaporator a is superior to a reference value C1.
This process thus allows to control only deliberately the defrosting and since the instructions value is supplied by the first measurement, it allows to be independent of the external conditions.
According to another characteristic, the difference APO is constant at the instant to, to a value CO, and the defrosting is controlled when APO is superior to CO. This value CO is selected according to the characteristics of the device. This stage of the process allows to ensure that the first measurement taken as reference, was not made in the presence of frost or any other undesirable parameter, and preferably, it is repeated several times if necessary and the installation is shut down if, after a number of trial runs, for example four, the difference APO has not become superior to the reference value CO.
Furthermore, according to another characteristic, the control of the evaporator is interrupted when the parameter P2 become superior to a reference value C2.
Preferably, the measured parameter is the temperature or indeed the pressure.
The invention also foresees a device for operating the process defined herein-above and which comprises at least two means allowing to measure a parameter representative of the fluid, each of the said means being situated on one side of the evaporator and being provided with means for generating unbroken signals representative of the said parameter, the processing means of these signals allowing at each instant to establish the difference between the values of the parameters measured by the said sensors and to compare this difference to that initially existing during the starting up of the installation in such a way as to be able to generate a control signal actuating a defrosting device of the evaporator in function of
the result of the said comparison.
According to the preferred embodiment, the
measuring means a temperature sensors
supplying an analogous signal and associated to
an analogous digital converter allowing to enter
these signals into a microprocessor constituting
the said processing treatment of the signals.
Furthermore, according to a preferential
characteristic of the invention, the temperature
measuring means comprise: - at least two temperature variable
resistances in which passes a roughly adjustable
intensity current and mounted in series with two
reference resistances; - multiplexing means of the signal provided
with at least four input channels of which at least
two each receive an analogous signal
representative of the voltage at the terminals of
the variable resistances and of which two among
the other each receive a signal representative of
the voltage at the terminals of the reference
resistances, these multiplexing means also
comprising an output channel and selection
means to choose at any instant one of the said
input channels in order to communicate it with the
said output channel;; -transformation means allowing to
transform the signals issuing from the multiplexing
means into alternate signals at which one of the constitutive parameters is proportional to the
voltage of the corresponding signal, the said
signals being directly processed by the
microprocessor.
According to the invention, the transformation
means can generate alternate signals of which the
period is proportional to the voltage of the
corresponding signal but it can, according to
another embodiment, generate signals of which
the frequency is proportional to the voltage of the
said signal.
According to a preferential embodiment of the
invention, the processing means are constituted
by a microprocessor allowing to make one
comparison per second.
Brief Description of the Drawings
The invention will be better understood by
reading through the following description of an
embodiment, given by way of non-limitative
example, said description made with reference to
the annexed drawings in which: - Figure 1 represents a first embodiment of
the invention.
- Figure 2 represents a second embodiment of
the invention.
Detailed Description of the Preferred Embodiment
Figure 1 represents schematically the
evaporation part of a heat pump to which is
associated a frost detection device according to
the invention.
The evaporator (1) in which circulates the
refrigerating fluid is placed in an air current (2)
produced by a ventilator (3). The circulation circuit
(4) of the refrigerating fluid comprises a pressurereducer (35). It is closed down by the remainder of the calories exchange installation of the heat pump represented by the rectangle (5) and which comprises, especially and in a usual way, a compressor and a condenser. The circuit (4) comprises a pass loop allowing the by-pass of the condensor and of the pressure-reducer (35). This loop is controlled by a three channel valve (7) associated to a servomotor (30). The ventilator (3) is provided with an electromagnetic switch (8).
Two temperature sondes (9) and (10) are placed in the air current (2), the sonde (9) upstream from the evaporator and the sonde (10) downstream.
Each of these sondes is connected to a microprocessor (4), by the intermediary of cables (12) and (13) and analogous digital converters (31) and (32).
The represented device operates in the following way. The system is put into normal operation; i.e. the refrigerating fluid circulates in the evaporator, the by-pass circuit (6) is shut down, the ventilator (3) supplies and sucks the air current (2) towards and through the evaporator (1), and the evaporator is not frosted. After a certain time t1, it is considered that the permanent state has been reached.
From time t, the monitoring microprocessor begins to operate and carries out, at instants t separated by regular time intervals of about 1 second, calculation of the difference AT between the temperature measured by the sonde 9 and that measured by the sonde 10. The first measurement made ATo is taken as a reference measurement and thus stored in memory. At each instant tj, the microprocessor compares ATi to ATo.
Once ATi becomes superior to ATo increased by a constant K, the microprocessor works out a signal actuating the switch (8) of the ventilator. This signal also acts on the servomotor (30) that actuates the three channel valve (7) in such a way that the refrigerating fluid circulates in the by-pass circuit (6). Simultaneously, the microprocessor monitors the temperature measured by the downstream sonde (10) and once the temperature returns above a limit value the microprocessor works out a new signal which by action of the switch (8) and the servomotor (30) reengages the system in normal operation so that the cycle is repeated as before.
This system thus carries out a monitoring of the installation on starting up which allows to take into account the situation where the evaporator would be frosted up during measurement of ATo, or that bound to faulty operation of the circulation circuit of the refrigerating fluid. In order to do this, the microprocessor compares the interval ATo to a iimit value and initiates the defrosting if ATo is superior to this value.
Indeed, in this case it is considered that the heat exchanger is not well done and that the evaporator is frosted up. This operation can be repeated a certain number of times until the obtention of normal operation but the microprocessor will actuate a total shut down if this normal operation is not obtained after a determined number of defrostings: for example 4.
This phase of the process thus allows to ensure that the value ATo, taken into account throughout the entire monitoring, corresponds to a normal state of the device.
Figure 2 represents a variant of the invention according to which the temperatures are measured by using a device comprising two probes mounted in parallel with two standard resistances, a multiplexer and a digital signal generator. The microprocessor assumes calculation of the temperatures and monitoring of the defrosting.
On Figure 2, the elements identical to those of
Figure 1 bear the same reference numerals. On either side of the evaporator are placed temperature sondes (101) and (102) each constituted by a resistance variable in function of the temperature. The two sondes are mounted in series with two reference resistances placed in the housing (103) that also allows the supply of the reference resistances assembly by direct current.
The cables (105) and (106) are four-wire conductors allowing positioning of the sondes and the resistances and also allowing the measurement of the voltage at the terminals of the variable resistances. A multiconductor cable (107) connects the housing (103) to a multiplexer
(109). This cable allows to supply the input bus of the multiplexer with voltages at the terminals of the variable resistances and at the terminals of the reference resistances. The output of the multiplexer is connected to an amplifier 10) then to an analogous-digital converter (111) which is connected to the microprocessor 12), itself connected to the multiplexer (109) by a transparent cable (120) of the control instructipns.
The microprocessor carries out the addressing of the multiplexer and the rules of three allowing the calculation of the temperatures and conducts the various operations necessary for detecting the presence of frost on the evaporator.
The analogous converter (111) is preferably a
VCO that supplies at its output a frequency proportional to the voltage present at the input.
It is also possible to use an impulse width modulator so that the microprocessor will work from a period, through counting the impulses of which the number is directly proportional to the period.
The represented device can comprise different monitoring elements allowing, for example, to verify that the ventilator is operating or that its access by external air is not hampered by elements such as dead leaves, for example.
This device is particularly well adapted to monitoring the evaporator of a heat pump such as that described in French patent application 80 60 103 "Heating Installation for Premises destined for Habitational or Industrial Use".
Furthermore, the present invention is not limited to the embodiments described, but, on the contrary, covers all the variants.
Claims (10)
1. Process for the monitoring and control of an evaporator in which circulates a first fluid, the said evaporator being in contact with a second fluid set in motion so as to through cross it, the second fluid being capable of transmitting its calories to the first fluid and of provoking its evaporation, the said process allowing to detect the presence of frost on the evaporator and its elimination, and consisting in measuring a parameter P 1 representative of the state of the second fluid upstream of the evaporator and parameter P2 representative of the state of the second fluid downstream of the evaporator, wherein these measurements are made at instances tj, determined from an initial instant, and wherein the process consists, furthermore, in calculating for each instant the difference AP existing between the two parameters P1 and P2, in comparing at each instant t, the difference AP with the difference APO measured at the initial instant, this comparison being made in the form of a subtraction of which the result is a parameter a and in controlling the defrosting of the evaporator when a is above a reference value C1.
2. Process according to claim 1, wherein the difference APo is compared at least once, at the instant to, to a reference value CO and the defrosting is controlled when APO is above value o
3. Process according to claim 1, wherein the defrosting control is interrupted when the parameter P2 returns to above reference value C2.
4. Process according to one of claims 1 to 3, wherein the parameter measured is the pressure.
5. Process according to one of claims 1 to 3, wherein the parameter measured is the temperature.
6. Monitoring and control device of an evaporator associated to a circulation circuit of a first refrigerating fluid and contacted with a second fluid set in motion by a ventilator in such a way as to through cross the evaporator, comprising at least one pair of temperature sensors situated on either side of the evaporator and contacted with the said second fluid, the processing means of the signals issuing from these sensors, the said means allowing at each instant to establish the difference between the temperatures measured by the two detectors, wherein the said means allow, furthermore, to compare this difference to the initial variation existing during the starting up of the installation so as to generate a control signal initiating a defrosting device of the evaporator in function of the circuit of the said comparison.
7. Device according to claim 6, wherein the temperature sensors generate a continuous signal representative of the temperature and wherein the said processing means are constituted by a microprocessor.
8. Device according to claim 7, wherein the temperature sensors are constituted by resistances variable with the temperature, through crossed by a roughly adjustable intensity current
and mounted in series with two reference resistances, the said device comprising, among others: - multiplexing means of the signal provided with at least four input channels, of which at least two each receive an analogous signal representative of the voltage at the terminals of the variable resistances and two of which among the others each receive a signal representative of the voltage at the terminals of the reference resistance, this multiplexing means also comprising an output channel and selection means allowing to select at each instant one of the said input channels in order to communicate it with the said output channel.
- transformation means allowing to transform the signals issuing from the multiplexing means into alternate signals of which one of the constitutive parameters is proportional to the voltage of the corresponding signal, the said signals being able to be directly processed by the microprocessor.
9. Device according to claim 8, wherein the transformation means generates alternate signals of which the period is proportional to the voltage of the corresponding signal.
10. Device according to claim 8, wherein the transformation means generates alternate signals of which the frequency is proportional to the voltage of the corresponding signal.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| FR8221549A FR2538518B1 (en) | 1982-12-22 | 1982-12-22 | METHOD AND DEVICE FOR MONITORING AND CONTROLLING AN EVAPORATOR |
Publications (3)
| Publication Number | Publication Date |
|---|---|
| GB8333757D0 GB8333757D0 (en) | 1984-01-25 |
| GB2133130A true GB2133130A (en) | 1984-07-18 |
| GB2133130B GB2133130B (en) | 1986-04-16 |
Family
ID=9280396
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB08333757A Expired GB2133130B (en) | 1982-12-22 | 1983-12-19 | Process and device for the monitoring and control of the defrosting of an evaporator |
Country Status (12)
| Country | Link |
|---|---|
| JP (1) | JPS59137772A (en) |
| BE (1) | BE898505A (en) |
| CA (1) | CA1216045A (en) |
| CH (1) | CH655781A5 (en) |
| DE (1) | DE3346563A1 (en) |
| ES (1) | ES8406704A1 (en) |
| FR (1) | FR2538518B1 (en) |
| GB (1) | GB2133130B (en) |
| IT (1) | IT1170050B (en) |
| NL (1) | NL8304412A (en) |
| PT (1) | PT77872B (en) |
| SE (1) | SE8307021L (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO1998054523A1 (en) * | 1997-05-30 | 1998-12-03 | Ranco Incorporated Of Delaware | Ice bank system |
| EP3764032A4 (en) * | 2018-03-08 | 2021-12-01 | LG Electronics Inc. | Refrigerator |
Families Citing this family (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4538420A (en) * | 1983-12-27 | 1985-09-03 | Honeywell Inc. | Defrost control system for a refrigeration heat pump apparatus |
| US4563877A (en) * | 1984-06-12 | 1986-01-14 | Borg-Warner Corporation | Control system and method for defrosting the outdoor coil of a heat pump |
| DE3642701C2 (en) * | 1986-12-13 | 1998-06-04 | Aeg Hausgeraete Gmbh | Warning device for a refrigerator and / or freezer |
| DE4005728A1 (en) * | 1990-02-23 | 1991-08-29 | Behr Gmbh & Co | Vehicle refrigeration circuit - has electrically-controlled thermostatic expansion valve controlled by line temp. between compressor and condenser |
| ES2069496B1 (en) * | 1993-08-10 | 1995-11-01 | Asturiana De Zinc Sa | TUB FOR ELECTROLYSIS FACILITIES. |
| DE102005054104A1 (en) * | 2005-11-12 | 2007-05-24 | Stiebel Eltron Gmbh & Co. Kg | Compression refrigerator e.g. ventilation system, controlling method, for e.g. heating room, involves determining control value by combining two control values and adjusting throttle body to determined control value |
| CN105783387B (en) * | 2016-04-29 | 2018-08-28 | 合肥美的电冰箱有限公司 | Defrosting control method, defrosting control device and refrigerator |
| WO2021144869A1 (en) * | 2020-01-15 | 2021-07-22 | 三菱電機株式会社 | Heat pump device |
Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB834985A (en) * | 1957-07-24 | 1960-05-18 | Ranco Inc | Control mechanism for refrigerating systems |
| GB904711A (en) * | 1959-01-02 | 1962-08-29 | Parnall & Sons Ltd | Improved means for de-frosting refrigerating apparatus |
| GB975197A (en) * | 1962-04-12 | 1964-11-11 | Stone J & Co Ltd | Improvements relating to means for controlling the defrosting of refrigerating units |
| GB1229003A (en) * | 1967-11-24 | 1971-04-21 | ||
| GB1261810A (en) * | 1968-07-26 | 1972-01-26 | Galt Equipment Ltd | Temperature control unit |
| GB1404210A (en) * | 1971-12-23 | 1975-08-28 | Philips Nv | Controlling refrigerator defrosting-apparatus |
| GB2064083A (en) * | 1979-11-12 | 1981-06-10 | Volvo Ab | Device for preventing icing of evaporators |
| GB1595741A (en) * | 1977-01-31 | 1981-08-19 | Carrier Corp | Defrost control for heat pumps |
Family Cites Families (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CA844775A (en) * | 1967-11-09 | 1970-06-16 | H. Ting Youn | Defrost control apparatus |
| AU410820B2 (en) * | 1968-12-02 | 1971-02-15 | An improved differential fluid flow detector | |
| SE7406316L (en) * | 1974-05-10 | 1975-11-11 | Projectus Ind Produkter Ab | PROCEDURE AND DEVICE FOR DEFROSTING EVAPORATORS FOR HEAT PUMPS. |
| JPS53148053A (en) * | 1977-05-30 | 1978-12-23 | Matsushita Electric Ind Co Ltd | Control method of defrosting |
| JPS5486839A (en) * | 1977-12-23 | 1979-07-10 | Hitachi Ltd | Heating/cooling device |
| US4209994A (en) * | 1978-10-24 | 1980-07-01 | Honeywell Inc. | Heat pump system defrost control |
| US4338790A (en) * | 1980-02-21 | 1982-07-13 | The Trane Company | Control and method for defrosting a heat pump outdoor heat exchanger |
| US4332141A (en) * | 1980-08-25 | 1982-06-01 | Honeywell Inc. | Defrost control system for refrigeration system |
| US4328680A (en) * | 1980-10-14 | 1982-05-11 | General Electric Company | Heat pump defrost control apparatus |
-
1982
- 1982-12-22 FR FR8221549A patent/FR2538518B1/en not_active Expired
-
1983
- 1983-12-19 SE SE8307021A patent/SE8307021L/en unknown
- 1983-12-19 CH CH6777/83A patent/CH655781A5/en not_active IP Right Cessation
- 1983-12-19 GB GB08333757A patent/GB2133130B/en not_active Expired
- 1983-12-20 BE BE0/212078A patent/BE898505A/en not_active IP Right Cessation
- 1983-12-20 ES ES528223A patent/ES8406704A1/en not_active Expired
- 1983-12-21 CA CA000443942A patent/CA1216045A/en not_active Expired
- 1983-12-21 JP JP58241793A patent/JPS59137772A/en active Pending
- 1983-12-21 PT PT77872A patent/PT77872B/en unknown
- 1983-12-22 DE DE3346563A patent/DE3346563A1/en not_active Withdrawn
- 1983-12-22 IT IT24344/83A patent/IT1170050B/en active
- 1983-12-22 NL NL8304412A patent/NL8304412A/en not_active Application Discontinuation
Patent Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB834985A (en) * | 1957-07-24 | 1960-05-18 | Ranco Inc | Control mechanism for refrigerating systems |
| GB904711A (en) * | 1959-01-02 | 1962-08-29 | Parnall & Sons Ltd | Improved means for de-frosting refrigerating apparatus |
| GB975197A (en) * | 1962-04-12 | 1964-11-11 | Stone J & Co Ltd | Improvements relating to means for controlling the defrosting of refrigerating units |
| GB1229003A (en) * | 1967-11-24 | 1971-04-21 | ||
| GB1261810A (en) * | 1968-07-26 | 1972-01-26 | Galt Equipment Ltd | Temperature control unit |
| GB1404210A (en) * | 1971-12-23 | 1975-08-28 | Philips Nv | Controlling refrigerator defrosting-apparatus |
| GB1595741A (en) * | 1977-01-31 | 1981-08-19 | Carrier Corp | Defrost control for heat pumps |
| GB2064083A (en) * | 1979-11-12 | 1981-06-10 | Volvo Ab | Device for preventing icing of evaporators |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO1998054523A1 (en) * | 1997-05-30 | 1998-12-03 | Ranco Incorporated Of Delaware | Ice bank system |
| US5987897A (en) * | 1997-05-30 | 1999-11-23 | Ranco Incorporated Of Delaware | Ice bank system |
| AU727544B2 (en) * | 1997-05-30 | 2000-12-14 | Ranco Incorporated Of Delaware | Ice bank system |
| EP3764032A4 (en) * | 2018-03-08 | 2021-12-01 | LG Electronics Inc. | Refrigerator |
| US11530866B2 (en) | 2018-03-08 | 2022-12-20 | Lg Electronics Inc. | Refrigerator |
Also Published As
| Publication number | Publication date |
|---|---|
| PT77872B (en) | 1986-04-09 |
| SE8307021D0 (en) | 1983-12-19 |
| JPS59137772A (en) | 1984-08-07 |
| ES528223A0 (en) | 1984-08-01 |
| GB2133130B (en) | 1986-04-16 |
| ES8406704A1 (en) | 1984-08-01 |
| FR2538518A1 (en) | 1984-06-29 |
| SE8307021L (en) | 1984-06-23 |
| FR2538518B1 (en) | 1986-04-04 |
| DE3346563A1 (en) | 1984-06-28 |
| CA1216045A (en) | 1986-12-30 |
| NL8304412A (en) | 1984-07-16 |
| GB8333757D0 (en) | 1984-01-25 |
| CH655781A5 (en) | 1986-05-15 |
| IT8324344A0 (en) | 1983-12-22 |
| IT1170050B (en) | 1987-06-03 |
| PT77872A (en) | 1984-01-01 |
| BE898505A (en) | 1984-04-16 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US4611470A (en) | Method primarily for performance control at heat pumps or refrigerating installations and arrangement for carrying out the method | |
| GB2133130A (en) | Process and device for the monitoring and control of the defrosting of an evaporator | |
| US3922527A (en) | Temperature control apparatus | |
| US4878355A (en) | Method and apparatus for improving cooling of a compressor element in an air conditioning system | |
| CA1150797A (en) | Heat pump system compressor start fault detector | |
| US3143167A (en) | Temperature controlled enclosure for testing purposes | |
| US4658596A (en) | Refrigerating apparatus with single compressor and multiple evaporators | |
| US5341649A (en) | Heat transfer system method and apparatus | |
| KR850003828A (en) | Thermal efficiency control device of steam pressure cooker | |
| US2556065A (en) | Electric control system for heating of enclosures | |
| KR850008208A (en) | Operation method and control system for refrigeration system | |
| US3165149A (en) | Temperature control system | |
| CA1233212A (en) | Measuring device for detecting a liquid component in refrigerant | |
| WO2000028395A1 (en) | Automatic temperature control | |
| CN102122169A (en) | Durability tester for temperature controller | |
| US4793553A (en) | Infrared thermostat control | |
| EP0001396B1 (en) | Method of cooking meat in a microwave oven | |
| ES424317A1 (en) | Evaporator temperature control for refrigeration systems | |
| US4183223A (en) | Method and apparatus for signal transmission in refrigeration units | |
| WO1995016230A1 (en) | An apparatus for controlling the operating temperature of a cooking zone | |
| US11585543B2 (en) | Orientation-based HVAC control | |
| EP0031945A2 (en) | Heat pump defrost control | |
| JPH0434050B2 (en) | ||
| US4202181A (en) | Fuel conservation controller for heating and refrigeration apparatus | |
| US4079887A (en) | Temperature control system |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PCNP | Patent ceased through non-payment of renewal fee |