Auto monitoring control circuit unit of heat exchanger in air conditioning system

Abstract

An auto monitoring control unit of a heat exchanger an air conditioning system, includes a detecting circuit detecting a heat exchange value at the heat exchanger of the air conditioning system, a reference circuit providing a heat exchange reference for the heat exchanger of the air conditioning system, a processing circuit receiving the heat exchange value from the detecting circuit and comparing the heat exchange value with the heat exchange reference to determine differential value therebetween, a control circuit receiving the differential value from the processing circuit so as to govern the air conditioning system in response to the differential value, and a monitoring circuit electrically connected with the control circuit to monitor the differential value so as to ensure the air conditioning system is functioning in a normal condition.

Description

BACKGROUND OF THE PRESENT INVENTION

[0001] 1. Field of Invention

[0002] The present invention relates to an air conditioning system, and more particularly to an auto monitoring control unit of a heat exchanger in an air conditioning system, which is capable of promptly and accurately adjusting heat exchange parameters of the air conditioning system so as to ensure efficient operation of that system.

[0003] 2. Description of Related Arts

[0004] Referring to FIG. 1, a schematic diagram of a conventional central air conditioning system which is primarily used for extremely large spaces such as shopping malls, commercial buildings, manufacturing plants etc. is illustrated. As shown in FIG. 1, the conventional air conditioning system comprises a compressing device 1, a cooling tower 2, a coolant pump 3, a refrigerant pump 4, and a heat exchange arrangement 5.

[0005] The compressing device 1 comprises a condenser 11, a compressor 12, and an evaporation device 13. The cooling tower 2 is communicatively connected to the condenser 11 through a coolant inlet pipe 111 and a coolant outlet pipe 112 for coolant water passing therethough. Furthermore, the heat exchange arrangement 5 is connected to the evaporation device 13 through a refrigerant inlet pipe 131 and a refrigerant outlet pipe 132. The coolant pump 3 is installed on the coolant inlet pipe 111 for pumping coolant passing through the coolant inlet pipe 111. On the other hand, the refrigerant pump 4 is installed on the refrigerant inlet pipe 131 for pumping refrigerant passing through the refrigerant inlet pipe 131.

[0006] The heat exchange arrangement 5 comprises a cooling coil 51, and a cool air delivering fan 52 communicated with a large space for delivering refrigerated air coming out from the cooling coil 51 to that large space so as to provide air conditioning. The operation of the air conditioning system is as follows: refrigerant coming out from the evaporation device 13 enters the cooling coil 51 which is essentially a plurality of heat exchangers, wherein heat is extracted from the refrigerated space in the heat exchangers. After passing through the heat exchangers, the refrigerant reenters the evaporation device 13 for cooling. The cycle continues.

[0007] On the other hand, the cooling of the refrigerant is accomplished by means of evaporation inside the evaporation device 13. The coolant entering the evaporation device 13 is evaporated as heat is extracted from the refrigerant. The vapor then leaves the evaporation device 13 and then reenters compressor 12 and the condenser 11 where the vapor condenses into the coolant again. In this condensation process, heat is transferred to ambient air outside the refrigerated space. After that, the coolant is directed to the cooling tower 2 for further reduction of temperature. In other words, the air conditioning system includes a plurality of heat exchange points between such heat changers for heat exchanging purpose.

[0008] One skilled in the art should recognize that the above-mentioned air conditioning process is of typical nature without introducing novel heat changers and process. There are several deep-seated drawbacks concerning the above-mentioned conventional air conditioning system—the most notorious one being high electricity consumption. For years, scientists and engineers have been working hard to reduce the electricity consumption of the air conditioning system. Yet, they mainly focus on individual heat changers which make up the air conditioning system, thinking like how to reduce the electrical consumption for each of the individual heat changers. One skilled in the art should appreciate that they have really made progress and improved the performance of most of the heat changers of the air conditioning system.

[0009] However, most of them overlook a significant factor affecting the energy consumption of the whole air conditioning system which is the actual air conditioning process. Engineering analysis easily reveals that there are significant drawbacks for conventional refrigerating systems and their process:

[0010] First, in designing a particular air conditioning system which is characterized by certain refrigerating parameters, such as flow rate of coolant and respective power of the pumping devices, a system engineer usually depends on the expected demand of the refrigerating system, plus a safety factor. In other words, the actual system parameters, such as the power of the pumping devices concerned, will be greater or better than required. As a result, unnecessary yet unavoidable, from the engineering's point of view, energy is wasted.

[0011] As an illustration, consider if the actual flow rate of coolant in a particular air conditioning system produced by a particular pumping device, such as a fan, is 267 m3/hr, running at an angular speed of 1750 rpm. Take, for example, the desire flow rate of the coolant of the air conditioning system is 190 m3/hr, then, by fan law (derived from dimensionless analysis), the required angular speed of the fan should be 1245 rpm, which is far less than the actual angular speed of 1750 rpm. Moreover, suppose the actual power of the pumping device is 45 kw, by the fan law again, the required power for the pumping device running at 1245 rpm can be calculated as 16.2 kw, which is far less than the actual pumping power. Thus, because of the engineering safety factor, energy is unnecessary, yet ‘unavoidably’ wasted. It would be helpful if one can contingently control the operational parameters of the pumping device in order to save energy.

[0012] Second, the air conditioning system usually fails to response to changing temperature of the incoming air. Very often, when the indoor temperature of the space in which the air conditioning system installs reaches the desirable temperature, the operational parameters of the pumping devices, especially the refrigerant pump 4, remain unchanged. This may make the whole air conditioning system consumes unnecessary electrical energy.

[0013] Third, even though the air conditioning system can respond to changing temperature of the incoming air, due to complicated heat transfer pattern for some highly varying temperature profile situations, such as at the ground floor of a shopping mall where the number of people changes frequently and rapidly, the system may not be able to respond promptly so as to create an optimal operational parameters for the air conditioning system. As a matter of fact, unnecessary changing of operational parameters can waste as much energy as the system does not change them at all. And this is the reason why obtaining an optimal response time in the field of Control Engineering, both for mechanical and electrical systems, is crucial and of overriding importance.

[0014] Fourth, some national engineering standards, such as the China National Standards (CNS), in air conditioning system suggest that the temperatures of the cooling tower 2 at the inlet and at the outlet should be 35° C. and 30° C. respectively for most efficient heat transfer. As a result, the cooling tower 2 should be adjusted to obtain the desirable inlet and outlet coolant temperatures. However, in reality, it is rare that the cooling tower can adjust to such desirable inlet and outlet temperatures because of varying environmental temperature. For example, the heat transfer requirement in summer and in winter is totally difference. Conventional air conditioning systems are mostly too inflexible to adapt to varying environmental circumstances. As a result, unnecessary electricity wastage is incurred.

[0015] From the operators' perspective, for some heavy-duty air conditioning systems, even though some insignificant mechanical failures occur, the operators or technicians of such systems can indeed hardly identify what is going wrong until an extensive inspection is performed. However, this may not be feasible in that extensive inspection often means serious interruption of daily operation of the place in which the refrigerating system is installed. Thus, the unnoticed mechanical failures may induce significant energy wastage or performance downgrading. Thus, a self regulating system may be required to fix such problems or to adjust operational parameters of the air conditioning system for optimal performance, even though during mechanical failure.

[0016] In connection with the operators, most conventional heavy-duty air conditioning system is incapable of identifying operator's fault so as to induce significant energy wastage. Thus, some sorts of altering mechanisms may be installed to alert the operators while there is something wrong with the air conditioning system.

SUMMARY OF THE PRESENT INVENTION

[0017] A main object of the present invention is to provide an auto monitoring control unit of a heat exchanger in an air conditioning system, which is capable of monitoring operational parameters of all the system's heat changers, comparing the operational parameters with a set of standard parameters, and commanding the corresponding system's heat changers to make suitable changes on those parameters so as to obtain optimal operation for saving operating energy of the air conditioning system.

[0018] Another object of the present invention is to provide an auto monitoring control unit of a heat exchanger in an air conditioning system, which is capable of illustrating the current operational parameters of the system's heat changers such that the operators of that air conditioning system can be able to respond promptly to exceptional circumstances or possible mechanical failures.

[0019] Another object of the present invention is to provide an auto monitoring control unit of a heat exchanger in an air conditioning system, which is capable of identifying any exceptional values of the operational parameters of the system's heat changers so as to identify the possible operator's carelessness in operating or repairing the air conditioning system.

[0020] Another object of the present invention is to provide an auto monitoring control unit of a heat exchanger in an air conditioning system, which neither involves complicated nor expensive mechanical and electrical heat changers so as to minimize the manufacturing cost and other related expenses in developing the air conditioning system of the present invention.

[0021] Accordingly, in order to accomplish the above objects, the present invention provides an auto monitoring control unit of a heat exchanger in an air conditioning system, comprising:

[0022] a detecting circuit detecting a heat exchange value at the heat exchanger of the air conditioning system;

[0023] a reference circuit providing a heat exchange reference for the heat exchanger of the air conditioning system;

[0024] a processing circuit receiving the heat exchange value from the detecting circuit and comparing the heat exchange value with the heat exchange reference to determine differential value therebetween;

[0025] a control circuit receiving the differential value from the processing circuit so as to govern the air conditioning system in response to the differential value; and

[0026] a monitoring circuit electrically connected with the control circuit to monitor the differential value so as to ensure the air conditioning system is functioning in a normal condition.

BRIEF DESCRIPTION OF THE DRAWINGS

[0027] FIG. 1 is a schematic diagram of a conventional air conditioning system.

[0028] FIG. 2 is a block diagram of an auto monitoring control unit of a heat exchanger in an air conditioning system according to a preferred embodiment of the present invention.

[0029] FIG. 3 is a circuit diagram of the automatic control system for the air conditioning system according to the above preferred embodiment of the present invention.

[0030] FIG. 4 is a schematic diagram of a monitoring circuit of the auto monitoring control unit of a heat exchanger in an air conditioning system according to the above preferred embodiment of the present invention, illustrating that a display be shown to the operators.

[0031] FIG. 5 illustrates a first alternative mode of the auto monitoring control unit of a heat exchanger in an air conditioning system according to the above preferred embodiment of the present invention.

[0032] FIG. 6 illustrates a second alternative mode of the auto monitoring control unit of a heat exchanger in an air conditioning system according to the above preferred embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

[0033] Referring to FIG. 2 of the drawings, an auto monitoring control unit of a heat exchanger in an air conditioning system according to a first preferred embodiment of the present invention is illustrated. As mentioning in the background, the air conditioning system comprises a plurality of heat changers such as an evaporation device, a compressor, a condenser, a cooling tower, and pumping devices.

[0034] The auto monitoring control unit comprises a detecting circuit 80 detecting a heat exchange value at each of the heat exchangers of the air conditioning system, a reference circuit 70 providing a heat exchange reference for each of the heat exchangers of the air conditioning system, a processing circuit 60 receiving the heat exchange values from the detecting circuit 80 and comparing the heat exchange values with the heat exchange references respectively to determine differential values therebetween respectively.

[0035] The auto monitoring control unit further comprises a control circuit 300 receiving the differential values from the processing circuit so as to govern the air conditioning system in response to the differential values, and a monitoring circuit 90 electrically connected with the control circuit 300 to monitor the differential values so as to ensure the air conditioning system is functioning in a normal condition.

[0036] According to the preferred embodiment, he detecting circuit 80 is operatively installed into the air conditioning system at the heat exchanger thereof to measure and obtain the heat exchange values of the air conditioning, such as the temperature at each of the heat exchangers of the air conditioning system before and after every state change. The detecting circuit 80 is electrically connected to the processing circuit 60 and the monitoring circuit 90 so that any detected parameters in a circuit readable form is sent to the processing circuit 60 and the monitoring circuit 90 for further manipulation as disclosed below.

[0037] The reference circuit 70 is electrically connected to the processing circuit 60 and provides the heat exchange reference for each of the heat exchangers of the air conditioning system wherein each of the heat exchange references is a predetermined standard heat exchange value in an electronic readable form for each of the heat exchange points of the air conditioning system. Therefore, according to the heat exchange references, the air conditioning system is capable of functioning in a normally optimum condition.

[0038] The processing circuit 60 is arranged to receive the heat exchange values from the detecting circuit 80 and the heat exchange references from the reference circuit 70 wherein the processing circuit 60 compares the heat exchange values with the heat exchange references to form the differential values in an electronic readable form respectively. The differential values is an algorithm that can be simply determined by pure addition or subtraction, or by sophisticated heat transfers equations which require micro-processor to calculate under some predetermined computer programs. It is worth mentioning that the processing circuit 60 is a central control center wherein all other circuits within the air conditioning system is electrically connected thereto for data retrieval or manipulation. The differential values are then transferred to the control circuit 300 and the monitoring circuit 90 for further manipulations.

[0039] The control circuit 300 is electrically connected to the processing circuit 60 and operatively linked to the heat changer of the air conditioning system so as to adjustably control each of the heat changers of the air conditioning system in the optimum condition that the heat exchange value matches the heat exchange reference. The control circuit 300 is arranged to send appropriate controlling signals, which depends upon the differential values, to each of the heat changers of the air conditioning system so as to regulate the heat transfers parameters of the air conditioning system for optimal or efficient system performance. The controlling signal can be something like reducing output power of the pumping devices so that the refrigerant will be circulated at a lower flow rate. Since the flow rate of the refrigerant significantly affects the amount of heat transferred to and from the refrigerant, optimal heat transfer can be achieved by altering the flow rate of the refrigerant.

[0040] The monitoring circuit 90 is electrically connected between the processing circuit 60, the reference circuit 70 and the detecting circuit 80 to display the heat exchange values from the detecting circuit 80, the heat exchange references from the reference circuit 70, and the differential values from the processing circuit 60. The purpose of which is to let the operators of the air conditioning system have enough and accurate information about the heat transfer parameters so that any strange values of the heat transfers parameters signaling possible mechanical or electrical failure can be detected and fixed as soon as possible.

[0041] Referring to FIGS. 3 to 4 of the drawings, the processing circuit 60 comprises a microprocessor, such as 8051 chip, the 8052 chip etc., programmed with fluids mechanics, thermodynamics and heat transfers equations governing the heat transfers within a refrigerating system so that the detected heat exchange values can be manipulated by those programs to obtain the appropriate set of the differential values. Accordingly, the reference circuit 70 has memories which store the standardized set of heat transfers parameters. The standards can be the orthodox British Standard (BS) or the International Standard Organization (ISO), or can be any national standards, depending on the actual situations and the operation venue of the air conditioning system of the present invention. The heat exchange references are preset as the normal temperatures of coolant water flowing in and out and the coolant water flowing in and out through the heat changers of the air conditioning system, and the normal temperatures of the compressor and the condenser of the air conditioning system.

[0042] The detecting circuit 80 comprises a plurality of temperature/flow measuring devices 81, such as a plurality of thermostats or thermometers, operatively installed into the heat changer to measure a desired parameter thereof, an amplifying device 82 for amplifying the measured parameters, and a converter 83 which converts and sends the parameter, generally analog signal such as temperature in degree Celsius into digital format of equal status, to the processing circuit 60 and the monitoring circuit 90. The temperature/flow measuring devices 81 are installed into the air conditioning system at the heat exchangers, i.e. the coolant pump 3, the refrigerant pump 4, the condenser 11, the evaporation device 13, the coolant inlet and outlet pipes 111, 112 of the condenser 11, and the refrigerant inlet and outlet pipes 131, 132 of the evaporation device 13 respectively, so as to measure, say, the temperature, the heat exchange values of the heat exchangers of the air conditioning system respectively.

[0043] The displaying circuit 90 comprises a display 91, such as a Light Emitting Diode (LED) or a Liquid Crystal Display (LCD), for displaying the various heat transfer parameters, wherein the display 91 is electrically connected to the processing circuit 60, the reference circuit 70 and the detecting circuit 60, as shown in FIG. 3, so as to display the heat exchange values from the detecting circuit 80, the heat exchange references from the reference circuit 70 and the differential values from the processing circuit 60.

[0044] As shown in FIG. 4, the display 91 has an optimal figure window 911 showing the heat exchange references from the reference circuit 70, an actual figure window 912 showing the heat exchange values from the detecting circuit 80, a difference window 913 showing the differential values from the processing circuit 60, a plurality of indicating menus 914 showing conditions of the heat exchangers of the air conditioning system respectively and a function key 915 for selecting the indicating menus 914. Accordingly, the indicating menus 914 indicating the temperatures of heat exchange points of the air conditioning system such as the coolant water flowing and the coolant water flowing, and volumes the coolant water and the coolant water. Moreover, each of the indicating menus 914 has an alert light 914a for alerting any technical strange situation leading to possible mechanical or electrical failure. In other words, by controlling the function key 915 to selectively govern the heat exchange points of the air conditioning system through the indicating menus 914, the heat exchange values at the heat exchangers will be monitored and controlled.

[0045] The control circuit 300 comprises a plurality of reversing logic gates 301 communicatively connected to the processing circuit 60, a current amplifier 302 electrically connected to the reversing logic gates 301, and a plurality of relays 303 which are electrically connected with current amplifier 302 and arranged to connect to switches of the heat changers of the air conducting system in such a manner that when the control circuit 300 sends out a control signal to the reversing logic gates 301, the control signal is send to the relays 303 through the current amplifier 302 for controlling the heat changers of the air conditioning system in an on and off manner. It is worth mentioning that the switches of the heat changers of the air conditioning system comprises a transformer of the compressor 12, a magnetic valve of the compressor 12, cooling fan 32 of the cooling tower 2, transformers of the coolant pump 3 and refrigerant pump 4, and a magnetic switch of the heat exchange arrangement 5.

[0046] The operation of the air conditioning system according to the first preferred embodiment of the present invention is elaborated as follows: When a temperature/flow measuring device 81 of the detecting circuit 80 has detected the heat exchange value of a particular heat exchanger of the air conditioning system, such as the flow rate of the refrigerant, an analog signal corresponding to that particular heat exchange value is then sent to the amplifying device 82 for amplifying and then to the converter 83 where the original analog signal is converted to an electrical signal. The converted electrical signal is then sent to the monitoring circuit 90 and the processing circuit 60. In the processing circuit, the microprocessor retrieves the heat exchange reference at that particular heat exchanger from the reference circuit 70 and than compare the heat exchange reference with the heat exchange value sent from the converter 83 to generate the differential value which is essentially the difference between the heat exchange value and the heat exchange reference.

[0047] According to the differential value, and depending on the program built into the microprocessor, it then determines the need to change the heat exchange value by adjusting some physical or electrical properties of the concerned individual heat changers of the air conditioning system. As an illustration, when the detecting circuit 80 is measuring the flow rate of the refrigerant while the heat exchange reference of the standard flow rate is less than the heat exchange value of the actual flow rate of the refrigerant, it is indicated that the refrigerating process needs to be continue, then, no controlling signal will be sent to the corresponding relay 303 of the control circuit 300 and the system remains unaltered. Moreover, the operator is able to monitor the condition of the refrigerant by selecting the indicating menu 913 via the function key 914 so as to display the corresponding heat exchange values of the flow rate of the refrigerant.

[0048] On the other hand, if the heat exchange reference of the standard flow rate is less than the heat exchange value of the actual flow rate of the refrigerant, it is indicated that the refrigerated space may be over-refrigerated. Therefore, a control signal of lowering down the flow rate of the refrigerant will be sent to the control circuit 300, in terms of, say, lowering the pumping power of the pumping device that circulates the refrigerant. In other words, the control signal is first sent to the appropriate reversing logic gate 301, and outputted to the relay 303 that control the power of the pumping device, via the amplifier 302, so that the flow rate of the refrigerant is controlled until the heat exchange value reaches the heat exchange reference.

[0049] Moreover, the heat exchange value and the differential value for that particular heat exchange point are sent to the monitoring circuit 90. In other words, the heat exchange value and the differential value, in terms of readable format, such as numerical or usual wordings, are shown to the operators of the air conditioning system for manual monitoring.

[0050] When the temperature of the refrigerated space substantially reaches the desirable level, the temperature of the refrigerant after passing through the evaporating device will reach to a certain predetermined value. Accordingly, when the temperature/flow measuring device, say, a thermometer positioned and arranged to measure the temperature of the refrigerant right after it leaves the evaporating device, a signal will be sent to the processing circuit 60 via the amplifying device 82 and the converter 83. The signal is then compared with the heat exchange reference corresponding to a standard temperature, then, the control signal will be sent to the control circuit 300 and finally to the concerned heat exchanger of the air conditioning system. In this case, the power of the compressor will be reduced so as to reduce the refrigerating effect of the system. Therefore, the objective of saving energy under suitable condition can be accomplished. Of course, when the temperature of the refrigerated space is increased again, the auto monitoring control circuit unit should be able to adjust the corresponding heat changers of the air conditioning system so as to activate the refrigerating process again.

[0051] It is worth mentioning that since the heat exchange reference stored in the reference circuit 70 is in accordance with established and authoritative engineering standards, large deviation from such data may represent possible mechanical or electrical failure which need technicians to fix it manually in order to prevent unnecessary consumption of substantial amount of energy. The CNS national standard (CNS 12812, B4075), suggests the heat exchange references that the temperature of the in-flowing coolant should maintain at 35° C., the temperature of the out-flowing coolant should maintain at 30° C, the in-flowing refrigerant should maintain at 12° C., and the out-flowing refrigerant should maintain at 7° C. According to the heat exchange references, the air conditioning system is functioning in the best mode while being energy effective. Moreover, the operator is able to monitor the air conditioning system through the optimal figure window 911, the actual figure window 912, and the difference window 913 of the display 91 so as to control the air conditioning system to reach the optimum condition manually.

[0052] According to the first preferred embodiment, the above-mentioned exception circumstances may be shown by the following events as detected by the auto monitoring control circuit unit, note that the following events are based on an assumption that the desirable room temperature of the refrigerated space is 25° C.:

[0053] 1. When the temperature of the out-flowing refrigerant is greater than 7° C., it reflects that there are two possible scenarios: (1.a) the corresponding temperature/flow measuring device 81 detects that the room temperature of the refrigerated space is greater than the desirable room temperature of 25° C., i.e. the refrigerated space has not reached the desirable room temperature, the control circuit 300 will keep the air conditioning system running under monitor; (1.b) after monitoring the air conditioning system for a period of time, if the room temperature is greater than 25° C. while the temperature of the heat absorbing medium reaches 7° C., it shows that the heat exchange rate of the cooling coil 51 of the heat exchange arrangement 5 cannot reach the optimum perform. Therefore, the operator should clean the cooling 51 to obtain the optimum perform thereof while being energy effective; (1.c) after cleaning the cooling coil 51, if the room temperature is still greater than 25° C. while the temperature of the heat absorbing medium reaches 7° C., it shows that mechanical failure of the heat exchangers or other heat changers of the air conditioning system. The operator is able to check the heat changers connected to the heat exchanger arrangement 5 in order to fix the problem.

[0054] 2. When the temperature of the out-flowing refrigerant is less than 7° C., it reflects that the room temperature of the refrigerated space reaches 25° C. Therefore, the control circuit 300 will automatically send the control signal to the air conditioning system as follow: (2.a) automatically higher the temperature of the refrigerant to minimize the flow rate of the heat absorbing medium to the compressor 12 so as to minimize the work done by the compressor 12 while being energy effective; (2.b) automatically higher the temperature of the refrigerant and lowing the cycling rate of the refrigerant to minimize the work done by the refrigerant pump 4 and the compressor 12; or (2.c) automatically lowering the cycle rate to minimize the rpm of the refrigerant pump 4 so as to minimize the work done by the refrigerant pump 4 while being energy effective.

[0055] 3. When the temperature of the out-flowing refrigerant is greater than 12° C., it reflects there are three possible scenarios: (3.a) the temperature of the refrigerated space has not yet reached the desirable 25° C., in this case, the control circuit 300 will allow the refrigerating process continues; (3.b) there is possible mechanical failure at the heat exchangers if the refrigerated space has temperature greater than 25° C., in this case, the cooling coil 51 of the heat exchange arrangement 5 need cleaning or repairing; (3.c) there are possible mechanical failures of individual heat changers of the air conditioning if after cleaning or repairing of the cooling coil 51, the room temperature is still greater than 25° C.

[0056] 4. When the temperature of the out-flowing refrigerant is less than 12° C., it reflects that the temperature of the refrigerated space reaches the desirable 25° C., thus, the controlling circuit will do one of the followings: (4.a) automatically higher the temperature of the refrigerant to minimize the flow rate of the refrigerant to the compressor 12 so as to minimize the work done by the compressor 12 while being energy effective; (4.b) automatically higher the temperature of the refrigerant and lowing the cycling rate of the refrigerant to minimize the work done by the refrigerant pump 4 and the compressor 12; or (4.c) automatically lowering the cycle rate to minimize the rpm of the refrigerant pump 4 so as to minimize the work done by the refrigerant pump 4 while being energy effective.

[0057] 5. When the temperature of the out-flowing coolant is greater than 35° C., it reflects that the temperature of the coolant is too high that the heat exchanger of the cooling tower 2 is not efficient and the compressing device 1 cannot reach its optimum performance. Therefore, the operator should appropriate inspect the tension of the belt of the fan 23 of the cooling tower 2 or whether the air inlet of the cooling tower 2 is stuck. In other words, by detecting the temperature of the coolant, the present invention ensures the cooling tower 2 functioning properly and efficiently.

[0058] 6. When the temperature of the out-flowing coolant is less than 35° C., it reflects that the heat exchanger of the cooling tower 2 is running effectively.

[0059] 7. When the temperature of the in-flowing coolant is greater than 30° C., which is too high, it reflects that the heat exchanger of the cooling tower 2 is ineffective and the compressing device 1 is functioning inefficient. Therefore, the operator should appropriate inspect the tension of the belt of the fan 23 of the cooling tower 2 or whether the air inlet of the cooling tower 2 is stuck in order to solve the above problems.

[0060] 8. When the temperature of the in-flowing coolant is less than 30° C., it reflects that the heat exchange of the cooling tower 2 is running effectively.

[0061] 9. One skilled in the art should realize that the evaporating temperature of the heat absorption medium must be lower than the temperature of the out-flowing refrigerant, whereas the condensation temperature of the heat absorption medium must be higher than the temperature of the out-flowing coolant. Conventionally, the evaporating temperature of the heat absorption medium is preferably 2° C. lower than the temperature of the out-flowing refrigerant, whereas the condensation temperature of the refrigerant is 2° C. higher than the temperature of the out-flowing coolant. According to the preferred embodiment, the evaporating temperature of the heat absorption medium is set as 5° C., whereas condensation temperature of the heat absorption medium is set as 37° C. As a result, when the evaporating temperature of the heat absorption medium is higher than 5° C., it reflects that the temperature of the refrigerated space has not reached the desirable 25° C., the control circuit 300 should allow the refrigerating process to continue.

[0062] 10. When the evaporating temperature of the heat absorption medium is less than 5° C., it reflects that the compressing device 1 is running at a low efficiency, operator's investigation is required whether the refrigerant is leaking or not.

[0063] 11. When the condensation temperature of the heat absorption medium is greater than 37° C., it reflects that the temperature of the coolant is too high such that the heat exchange of the cooling tower 2 is ineffective and the compressing device 1 is functioning inefficient. Therefore, the operator should appropriate inspect the tension of the belt of the fan 23 of the cooling tower 2 or whether the air inlet of the cooling tower 2 is stuck in order to solve the above problems.

[0064] 12. When the condensation temperature of the heat absorption medium is less than 37° C., it reflects that the cooling tower is running properly, the control circuit 300 will thus allow the refrigerating process to continue.

[0065] Note that the temperature/flow measuring device 81 of the detecting circuit 80 will send the heat exchange value to the control circuit 300 for switching on the fan 23 of the cooling tower 2 when the temperature/flow measuring device 81 detects the temperature of the out-flowing coolant is the same as that of the in-flowing coolant while the fan 23 of the cooling tower 2 is switch off due to the check up. Therefore, the present invention provides an indication of objective figures which can lead to subjective diagnosis of the possible failure of the air conditioning system.

[0066] FIG. 5 illustrates a first alternative mode of the auto monitoring control circuit unit according to the preferred embodiment of the present invention, wherein the auto monitoring control circuit unit further comprises means 100 for generating a warning signal when one of the differential values is out of a safety range that preset in the processing circuit 60. Accordingly, the warning signal means 100 is a voice alerting circuit electrically connected to the processing circuit 60. Specifically, the warning signal means 100 comprises a verbal analysis integrated chip (IC) 101, a speaker activation circuit 102, and a voice producing device 103. When the processing circuit 60 has determined that an exceptional circumstance occurs as mentioned above, in addition to controlling the concerned heat changers of the air conditioning system, it will send the warning signal to the verbal analysis IC 101 which then activates the speaker activation circuit 102 to drive the voice producing device 103 to produce a predetermined format of verbal warning signal. Therefore, the operator is able to determine a possible failure of the air conditioning system as soon as possible.

[0067] FIG. 6 illustrates a second alternative of the auto monitoring control circuit unit, which further comprises means 200 for manually inputting heat exchange data as the heat exchange reference in the processing circuit 60. The inputting means 200 is an input circuit electrically connected to the processing circuit 60 wherein the inputting means 200 comprises an input operator 201, such as a keyboard, for a user of the air conditioning system to key in the heat exchange date in the processing circuit 60. Thus, the air conditioning system of the present invention is capable of adapting various standards so as to fit actual operation circumstances. Accordingly, the inputting means 200 can further comprises a clear operator 203 and a setup operator 202 to erase the original heat exchange references in the processing circuit 60 and to configure the heat exchange data as the heat exchange reference in the processing circuit 60 respectively.

[0068] In view of above, the auto monitoring control circuit unit of the present invention can effectively governing the entire air conditioning system by detecting the beat exchange values at the heat exchangers of the air condition system and comparing the heat exchange values with the heat exchange references respectively. Therefore, in response to the differential values, the control circuit 300 can effectively control the heat changers of the air conditioning system in an on and off manner so as to guide the air conditioning system in the optimum performance while being energy effective. Thus, the auto monitoring control circuit unit of the present invention can diagnosis of the possible failure of the air conditioning system due to the manual mistake.

Claims

1. An auto monitoring control circuit unit of a heat changer in an air conditioning system, comprising:

a detecting circuit detecting a heat exchange value at said heat exchanger of said air conditioning system;

a reference circuit providing a heat exchange reference for said heat exchanger of said air conditioning system;

a processing circuit receiving said heat exchange value from said detecting circuit and comparing said heat exchange value with said heat exchange reference to determine differential value therebetween;

a control circuit receiving said differential value from said processing circuit so as to govern said heat changer of said air conditioning system in response to said differential value; and

a monitoring circuit electrically connected with said control circuit to monitor said differential value so as to ensure said heat changer of said air conditioning system is functioning in an optimum condition in response to said heat exchange reference.

2. The auto monitoring control circuit unit, as recited in claim 1, wherein said detecting circuit comprises at least a temperature/flow measuring device operatively installed into said heat changer to measure a desired parameter thereof, an amplifying device for amplifying said parameter of said heat changer, and a converter converting and sending said parameter to said processing circuit.

3. The auto monitoring control circuit unit, as recited in claim 1, wherein said reference value is stored in said reference circuit and arranged in such a manner that when said heat changer performs under said reference value, said air conditioning system functions in said optimum condition.

4. The auto monitoring control circuit unit, as recited in claim 2, wherein said reference value is stored in said reference circuit and arranged in such a manner that when said heat changer performs under said reference value, said air conditioning system functions in said optimum condition.

5. The auto monitoring control circuit unit, as recited in claim 1, wherein said control circuit comprises at least a reversing logic gate communicatively connected to said processing circuit, a current amplifier electrically connected to said reversing logic gate, and at least a relay which is electrically connected between said current amplifier and said heat changer in such a manner that when said control circuit sends out a control signal to said reversing logic gate, said control signal is amplified and sent to said relay through said current amplifier so as to adjustably control said heat changer in an on and off manner.

6. The auto monitoring control circuit unit, as recited in claim 2, wherein said control circuit comprises at least a reversing logic gate communicatively connected to said processing circuit, a current amplifier electrically connected to said reversing logic gate, and at least a relay which is electrically connected between said current amplifier and said heat changer in such a manner that when said control circuit sends out a control signal to said reversing logic gate, said control signal is amplified and sent to said relay through said current amplifier so as to adjustably control said heat changer in an on and off manner.

7. The auto monitoring control circuit unit, as recited in claim 4, wherein said control circuit comprises at least a reversing logic gate communicatively connected to said processing circuit, a current amplifier electrically connected to said reversing logic gate, and at least a relay which is electrically connected between said current amplifier and said heat changer in such a manner that when said control circuit sends out a control signal to said reversing logic gate, said control signal is amplified and sent to said relay through said current amplifier so as to adjustably control said heat changer in an on and off manner.

8. The auto monitoring control circuit unit, as recited in claim 1, wherein said monitoring circuit comprises a display which is electrically connected to said processing circuit and comprises an optimal figure window for showing said heat exchange reference from said reference unit, an actual figure window for showing said heat exchange value from said detecting circuit, and a difference window for showing said differential value from said processing circuit.

9. The auto monitoring control circuit unit, as recited in claim 2, wherein said monitoring circuit comprises a display which is electrically connected to said processing circuit and comprises an optimal figure window for showing said heat exchange reference from said reference unit, an actual figure window for showing said heat exchange value from said detecting circuit, and a difference window for showing said differential value from said processing circuit.

10. The auto monitoring control circuit unit, as recited in claim 4, wherein said monitoring circuit comprises a display which is electrically connected to said processing circuit and comprises an optimal figure window for showing said heat exchange reference from said reference unit, an actual figure window for showing said heat exchange value from said detecting circuit, and a difference window for showing said differential value from said processing circuit

11. The auto monitoring control circuit unit, as recited in claim 5, wherein said monitoring circuit comprises a display which is electrically connected to said processing circuit and comprises an optimal figure window for showing said heat exchange reference from said reference unit, an actual figure window for showing said heat exchange value from said detecting circuit, and a difference window for showing said differential value from said processing circuit.

12. The auto monitoring control circuit unit, as recited in claim 7, wherein said monitoring circuit comprises a display which is electrically connected to said processing circuit and comprises an optimal figure window for showing said heat exchange reference from said reference unit, an actual figure window for showing said heat exchange value from said detecting circuit, and a difference window for showing said differential value from said processing circuit.

13. The auto monitoring control circuit unit, as recited in claim 7, further comprises means for generating a warning signal when said differential value is out of a safety range preset in said processing circuit.

14. The auto monitoring control circuit unit, as recited in claim 12, further comprises means for generating a warning signal when said differential value is out of a safety range preset in said processing circuit.

15. The auto monitoring control circuit unit, as recited in claim 13, wherein said warning signal means comprises a voice alerting circuit electrically connected to said processing means, and comprises a verbal analysis integrated chip, a speaker activation circuit, and a voice producing device, wherein in response to an unusual operational condition, said warning signal is sent from said processing means to said verbal analysis integrated chip which is capable of activating said speaker activation circuit to activate said voice producing device to produce a predetermined format of verbal alert.

16. The auto monitoring control circuit unit, as recited in claim 14, wherein said warning signal means comprises a voice alerting circuit electrically connected to said processing means, and comprises a verbal analysis integrated chip, a speaker activation circuit, and a voice producing device, wherein in response to an unusual operational condition, said warning signal is sent from said processing means to said verbal analysis integrated chip which is capable of activating said speaker activation circuit to activate said voice producing device to produce a predetermined format of verbal alert.

17. The auto monitoring control circuit unit, as recited in claim 7, further comprising means for manually inputting heat exchange data as said heat exchange reference in said processing circuit.

18. The auto monitoring control circuit unit, as recited in claim 12, further comprising means for manually inputting heat exchange data as said heat exchange reference in said processing circuit.

19. The auto monitoring control circuit unit, as recited in claim 17, wherein said inputting means comprises an input operator for keying in said heat exchange data in said processing circuit, a clear operator for erasing an original heat exchange reference in said processing circuit, and a setup operator for configuring said heat exchange data as said heat exchange reference in said processing circuit.

20. The auto monitoring control circuit unit, as recited in claim 18, wherein said inputting means comprises an input operator for keying in said heat exchange data in said processing circuit, a clear operator for erasing an original heat exchange reference in said processing circuit, and a setup operator for configuring said heat exchange data as said heat exchange reference in said processing circuit.