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
  • F25D29/00—Arrangement or mounting of control or safety devices
• • 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
  • F25B2600/00—Control issues
  • F25B2600/02—Compressor control
  • F25B2600/025—Compressor control by controlling speed
  • F25B2600/0251—Compressor control by controlling speed with on-off operation
• • 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
  • F25D17/00—Arrangements for circulating cooling fluids; Arrangements for circulating gas, e.g. air, within refrigerated spaces
  • F25D17/04—Arrangements for circulating cooling fluids; Arrangements for circulating gas, e.g. air, within refrigerated spaces for circulating air, e.g. by convection
  • F25D17/06—Arrangements for circulating cooling fluids; Arrangements for circulating gas, e.g. air, within refrigerated spaces for circulating air, e.g. by convection by forced circulation
  • F25D17/062—Arrangements for circulating cooling fluids; Arrangements for circulating gas, e.g. air, within refrigerated spaces for circulating air, e.g. by convection by forced circulation in household refrigerators
• • 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
  • F25D2400/00—General features of, or devices for refrigerators, cold rooms, ice-boxes, or for cooling or freezing apparatus not covered by any other subclass
  • F25D2400/28—Quick cooling
• • 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
  • F25D2500/00—Problems to be solved
  • F25D2500/04—Calculation of parameters
• • 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
  • F25D2700/00—Means for sensing or measuring; Sensors therefor
  • F25D2700/12—Sensors measuring the inside temperature

Definitions

• the present invention refers to a thermal load compensating system that automatically adjusts the operational temperature in a refrigeration appliance of the type which comprises a compressor, optionally at least one fan, and a control means for activating and deactivating the compressor and/or the fan (if existing) as a function of the variations of the temperature reigning inside a refrigeration compartment which can be defined in a cabinet of a refrigerator or freezer or in a room of any building or construction.
• the present invention refers to a system that changes the behavior of the appliance in order to obtain a better performance/recovery of the adequate operational temperature for the loads to be refrigerated, according to the operational conditions to which the appliance is submitted (thermal loads, opening of the refrigeration compartment door) .
• the operation of the appliance is implemented in an electronic control means to be mounted in the refrigerator, freezer, air conditioner or other similar refrigeration appliance.
• the present invention is designed to be applied to domestic refrigeration appliances provided with a single speed compressor and in the form of a refrigerator, a freezer, or even an air conditioner, in which the refrigeration compartment, as generically denominated hereinafter, presents a respective adjusting device, generally in the form of a knob operatively associated with a control means, which allows the user to modify the operational conditions of the appliance, altering the activation and deactivation temperatures of the compressor and/or the fans to cooler or less cool values from a nominal medium operational value.
• the control means is operatively associated with means to detect the current temperature in the refrigeration compartment and to check whether said temperature is in the same level or above the activation temperature of the compressor so as to activate the latter.
• the control means provides the deactivation of the latter.
• This operational system makes the temperature inside the refrigeration compartment oscillate between the activation and deactivation temperatures of the compressor.
• control means is constructed so as to detect when the temperature reigning inside the refrigeration compartment, measured by the temperature sensor, surpasses the activation temperature of the compressor due to an event that provokes said temperature rise, and the control means is designed to adjust, to lower values, the deactivation temperature of the compressor and also, optionally and if necessary, the activation temperature of the compressor, in order to minimize the temperature variations to which the load is submitted.
• control means verifies the occurrence of the anomalous temperature rise in the refrigeration compartment and instructs a corresponding adjustment to be effected in the deactivation temperature of the compressor, the adjustment of the deactivation temperature of the compressor being achieved as a function of the value of the anomalous temperature, allowing the refrigeration system to respond, taking into account only the deviation of the temperature detected by the temperature sensor, i.e., the deviation of the temperature reigning inside the refrigeration compartment .
• the control system of the type mentioned above does not adjust the deactivation temperature of the compressor as a function of the periods of time in which the temperature varies between predetermined values, failing to consider the inertia of the thermal load imposed to the refrigeration compartment, thereby preventing the compressor from operating to provide a more rapid recovery of the temperature of the load stored in the refrigeration compartment.
• a general object of the present invention to provide a system for automatically adjusting the deactivation temperature of the compressor of a refrigeration appliance, such as a freezer, refrigerator, or air conditioner, as a function of anomalous temperature rises inside a refrigeration compartment, containing a thermal load, for example food products, in order to promote a rapid recovery of the desired operational temperature of said load. It is a further object of the present invention to provide a system as described above, which can be applied to a refrigeration appliance without requiring any additional components, such as a sensor or an electronic component, i.e., without increasing the cost of the appliance.
• a thermal load compensating system for a refrigeration appliance of the type which comprises a compressor associated with a refrigeration circuit, a temperature sensor provided inside a refrigeration compartment, and a control means operatively associated with both the compressor and the temperature sensor and which is provided with a timer and constructed to activate and deactivate the compressor when the interior of the refrigeration compartment reaches activation and deactivation temperatures, respectively.
• the refrigeration appliance can further contain one or more fans for distributing cool air to different and respective refrigeration compartments.
• the control means may actuate in the operation of both the compressor and the fans .
• control means is constructed in such a way as to alter the deactivation temperature of the compressor and/or the fan, whenever in an operational cycle of the compressor the temperature decrease rate between the activation and deactivation values deviates, by a certain predetermined value, from a reference temperature decrease rate of the refrigeration compartment, obtained in at least one previous operational cycle of the compressor and stored in the control means, the alteration in the deactivation temperature of the compressor being directly proportional to the variation, detected by the control means, of the temperature decrease rate in relation to the reference temperature decrease rate.
• control means to automatically adjust the deactivation temperature of the compressor when both the temperature sensor of the refrigeration compartment and the timer (measuring the time elapsed between the limits of the activation and deactivation temperatures of the compressor) detect, in relation to at least one previous operational cycle, a reduction of the temperature decrease rate between the limits of the temperature range being used by the refrigeration appliance .
• Figure 1 is a schematic median vertical sectional view of a refrigerator -presenting a refrigeration compartment and provided with the present thermal load compensating system
• Figure 2 is a schematic diagram showing how the temperatures of the food (thermal load) and of the refrigeration compartment (detected by the sensor) vary in relation to time in a conventional refrigeration appliance;
• Figure 3 is a schematic diagram showing how the temperatures of the food (thermal load) and of the refrigeration compartment (detected by the sensor) vary in relation to time in a refrigeration appliance provided with the system of the present invention
• Figure 4 is a block diagram showing the characteristics of the actuation of the control means of a refrigeration appliance provided with the present thermal load compensating system.
• the invention is related to a system for adjusting the operational temperature in a refrigeration appliance of the type which comprises a cabinet 10 defining at least one refrigeration compartment RC closed by a front door 11.
• the refrigeration appliance further comprises a refrigeration circuit, which is not illustrated, except the part defined by the compressor 20 operatively associated with a control means 30 provided with a timer 31 and which is constructed in any known adequate manner to activate and deactivate the compressor 20 when the interior of the refrigeration compartment RC reaches activation and deactivation temperatures, respectively, detected by a temperature sensor 40 positioned inside the refrigeration compartment RC to sense the air temperature reigning inside the latter.
• the temperature sensor 40 is also operatively associated with the control means 30 to indicate to the latter when the air temperature inside the refrigeration compartment RC reaches any of the activation and deactivation values of the compressor 20, said activation and deactivation temperatures, specific in different operational temperature ranges, being associated with different operational conditions of the refrigeration appliance.
• the refrigeration appliance can be of the type that comprises two or more refrigeration compartments RC, one of them defining, for example, a refrigeration compartment and another one defining a freezing compartment, which compartments are designed to be operated through independent controls operatively associated with air temperature sensors inside the compartment .
• the refrigeration appliance can also be of the forced ventilation type provided with only one fan 50 operatively associated with an evaporator 55, or with two fans, one associated with a refrigeration compartment and the other with a freezing compartment, in the case of a combined refrigerator-freezer appliance.
• Figure 2 schematically illustrates the temperature variation standards of the thermal load and of the refrigeration compartment RC detected by the temperature sensor 40.
• the temperature of the refrigeration compartment (or the temperature in the temperature sensor 40) oscillates between the upper and lower limits adjusted for the compressor operation, while the load temperature oscillates between upper and lower values contained within the temperature variation range of the refrigeration compartment.
• the diagram presented herein refers to an operational condition particularly associated with a freezing compartment of a refrigeration appliance.
• a special event such as for example the opening of the door 11 for an excessively long time, or the introduction of a relevant load (food) in the interior of the refrigeration compartment, said load being at a temperature substantially higher than that reigning inside the refrigeration compartment RC.
• a relevant load food
• the temperature of the refrigeration compartment rises abruptly, which does not occur with the previously stored load already presenting its temperature within the desired range.
• a new "hot" load is introduced at the instant B, the temperature of the refrigeration compartment rises rapidly, accompanying the high temperature of the load and indicating the need of occurring an alteration in the operation of the refrigeration system, since more heat must be removed from the refrigeration compartment RC to compensate for the additional thermal load.
• Figure 3 illustrates a diagram similar to that of figure 2, but illustrating the temperature variation standards of the thermal load and of the refrigeration compartment sensed by the temperature sensor 40, when the refrigeration appliance is provided with the compensating system of the present invention.
• the period of time A of the diagram is identical to that showed in figure 2 diagram, but with a special event occurring at the instant B, as described above in relation to the introduction of a "hot" load in the refrigeration compartment RC, the temperature of the refrigeration compartment rises rapidly, accompanying the temperature of the added thermal load and providing the activation of the compressor 20.
• the control means 30 upon detecting a rapid and intense temperature rise inside the refrigeration compartment RC, promotes a corresponding decrease in the deactivation temperature of the compressor 20, as illustrated in figure 3, accelerating the refrigeration of the load, so that the latter reaches the desired operational range in a time D substantially shorter than the time C required in the conventional systems .
• the difference between the two recovery times of the load temperature is defined by the period of time E (figure 3) which can be of several minutes or several hours .
• control means 30 is designed to reduce (alter) the deactivation temperature of the compressor 20 when the temperature decrease rate in an operational cycle of the compressor 20 deviates, by a certain predetermined value, for example of the order of 25%, from a basic temperature decrease rate obtained in at least one previous operational cycle of the compressor 20.
• the alteration of the deactivation temperature could be made both downwardly and upwardly, since the temperature decrease rate in a determined operational cycle of the compressor 20 can be higher than the reference temperature decrease rate preferably obtained as an average of the temperature decrease rates occurred in the previous operational cycles of the compressor 20 recorded in the control means 30.
• the present system measures the temperature decrease rate (ratio of the difference between the activation and deactivation temperatures to the elapsed time for said decrease) , by comparing the temperature decrease rate with a reference rate, generally representative of the average of the temperature decrease rates of the previous operational cycles of the compressor 20 and which is calculated and stored in the control means 30.
• the temperature sensor 40 detects the air temperature of the refrigeration compartment RC, indicating an increase in its measured temperature.
• the temperature lowers again, according to a new decrease rate, determined by the total thermal load in the interior of the refrigeration compartment RC defined after the introduction of the additional load and which takes into account the time during which the doors remains open and the quantity/temperature of the load introduced.
• the control means 30 measures the temperature decrease rate. If this rate is lower than the reference rate, it means that a loading occurred and that a corrective action is needed. There is also a relationship between the quantity of the thermal load introduced and how much the temperature decrease rate changes. That is to say, the more thermal load, the lower will be the rate .
• the present system is designed, through the fixation of two known temperature intervals, to measure the time between both intervals (indirectly measuring the temperature decrease rate) and to compare with the average of the decrease rates. If this value that is read is close to the previous average value, it means that no loading occurred in the system.
• the control means 30 considers that it is a case of extra cooling and changes the deactivation temperature of the compressor, which is altered to a lower temperature, thus keeping the compressor switched on for a longer time. This action may or may not be proportional to the loading and, consequently, may or may not offer a visual indication to the user that the deactivation temperature has been reduced as a function of the thermal load imposed to the refrigeration compartment .
• the decrease of the .deactivation temperature of the compressor 20 modifies the value of said temperature, corresponding to the value of the activation and deactivation temperature operational range being used in the moment of adjustment, to a value corresponding to that of a lower range in a scale of activation and deactivation temperature ranges of the compressor 20. It is also possible a situation in which the intensity of the decrease of the temperature operational range, defined in a determined operational cycle of the compressor, corresponds to activation and deactivation temperatures lower than those of the lowest temperature range in the scale of the activation and deactivation temperature operational ranges of the compressor 20. When this occurs, the control means 30 instructs to repeat the decrease of the activation and deactivation temperature operational range during a subsequent operational cycle of the compressor, aiming at bringing the temperature of the stored product, and consequently of the interior of the refrigeration compartment, to desired values.
• Figure 3 illustrates the actuation procedures or steps of the control means 30 during the operation of the refrigeration appliance, and as a function of the parameters received from both the temperature sensor 40 and the timer 31, in order to effect, when necessary, an adjustment in the deactivation temperature of the compressor 20 and/or the fan 50 (when existing) , considering the application of the system for adjusting the temperature of a refrigeration compartment or a freezing compartment generically denominated herein as refrigeration compartments .
• T 0n activation temperature of the compressor 20 and/or the fan 50;
• T of f deactivation temperature of the compressor 20 and/or the fan 50
• T d temperature decrease rate
• T x reference rate, which corresponds to the temperature decrease rate in each operational cycle of the compressor 20
• T dev percent deviation value of the temperature decrease rate (in the example, of the order of 25%) .
• the present compensating system starts the operation with the activation of the compressor 20 at temperature T 0n previously defined in the project of the refrigeration appliance and detected by the temperature sensor 40 located inside the refrigeration compartment RC.
• the compressor 20 is maintained activated by the control means until the temperature inside the refrigeration compartment RC and measured by the temperature sensor 40 reaches a temperature value T O ff .
• the control means 30 compares the temperature decrease rate T d , measured until the event cited above, with the previous temperature decrease rate or reference rate T x .
• the control means 30 deactivates the compressor 20.
• the control means 30 assumes a new temperature deactivation value T off , to only then switch off the compressor 20.
• the control means 30 further calculates and records a reference temperature decrease rate T x in said operational cycle of the compressor 20, said rate being equal to the ratio of the difference between the activation temperature T 0n and the deactivation temperature T O ff to the elapsed time.
• the control system Upon start of the operation of the refrigeration appliance, the control system has the parameter of the previous temperature decrease rate or reference rate T x erased.
• the temperature decrease rate T d is compared with the previous reference temperature decrease rate T x obtained in the previous cycle (s), said previous reference temperature decrease rate T x being obtained as an average of the temperature decrease rates T d obtained and recorded in the previous cycles.

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• 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)
• Devices That Are Associated With Refrigeration Equipment (AREA)
• Air Conditioning Control Device (AREA)

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Cited By (1)

Citations (4)

• 2005
  • 2005-02-21 BR BRPI0500666 patent/BRPI0500666A/pt not_active IP Right Cessation
• 2006
  • 2006-02-16 AR ARP060100557 patent/AR053021A1/es unknown
  • 2006-02-20 WO PCT/BR2006/000032 patent/WO2006086866A1/en active Application Filing

Patent Citations (4)

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