CA1207059A - Specific coefficient of performance measuring device - Google Patents
Specific coefficient of performance measuring deviceInfo
- Publication number
- CA1207059A CA1207059A CA000433137A CA433137A CA1207059A CA 1207059 A CA1207059 A CA 1207059A CA 000433137 A CA000433137 A CA 000433137A CA 433137 A CA433137 A CA 433137A CA 1207059 A CA1207059 A CA 1207059A
- Authority
- CA
- Canada
- Prior art keywords
- motor
- performance
- power
- coefficient
- storage means
- 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.)
- Expired
Links
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
- G01L3/00—Measuring torque, work, mechanical power, or mechanical efficiency, in general
- G01L3/26—Devices for measuring efficiency, i.e. the ratio of power output to power input
-
- 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
- F25B2500/00—Problems to be solved
- F25B2500/19—Calculation of parameters
Abstract
ABSTRACT OF THE DISCLOSURE
By measuring the power supplied to a compressor motor and by measuring four temperatures within a mechan-ical vapor-compression system, it is possible to develop a device for measuring and/or displaying the specific coefficient of performance of the mechanical vapor-compression system. The use of the temperatures and power supplied to the compressor motor can be used with information on motor losses and a typical temperature-enthalpy and a typical pressure-entropy dia-gram to allow substantially instantaneous computation of the actual specific coefficient of performance of a mechanical vapor-compression system as it operates. The measuring device can usually be installed totally exter-nal to a building in which the mechanical vapor-compression system is being used as a cooling sys-tem, or as a heat pump for heating and cooling.
By measuring the power supplied to a compressor motor and by measuring four temperatures within a mechan-ical vapor-compression system, it is possible to develop a device for measuring and/or displaying the specific coefficient of performance of the mechanical vapor-compression system. The use of the temperatures and power supplied to the compressor motor can be used with information on motor losses and a typical temperature-enthalpy and a typical pressure-entropy dia-gram to allow substantially instantaneous computation of the actual specific coefficient of performance of a mechanical vapor-compression system as it operates. The measuring device can usually be installed totally exter-nal to a building in which the mechanical vapor-compression system is being used as a cooling sys-tem, or as a heat pump for heating and cooling.
Description
A SPECIFIC COEFFICIENT OF PERFORMANCE MEA~SURlNG DEVICE
BACKGROUND OF THE INVENTION
To measure the coefficient of performance of a mechanical vapor-compression refrigeration system, two S parameters must be known. These parameters are the input power, and the heat rejected (in the case of heating) or the heat absorbed (in the case of cooling). Currently, manufacturers test mechanical vapor-compression systems by measuring input power directly with a power transducer or indirectly with an ammeter, and by measuring the heat rejected or absorbed with a large environmental chamber.
This method allows accurate coefficient of performance measurement, however, it does not lend itsalf to applica-tion in the field, whether in the research laboratory or at a specific site, such as a home in which a heat pump or air conditioning system of the vapor-compression type is installed.
m e need to measure the coefficient of perfor-mance of an air conditioning system or a heat pump has been recognized and is becoming more and more important with the widespread use of heat pumps as an energy effi-cient approach to heating and cooling. Attempts to provide measurements of the coefficient of performance have been undertaken by measurements of certain tempera-.~
n~
tures at a specific installation, but these measurementsallow for only a relative coefficient of performance to be provided. The relative coefficient of performance provides a measure only of whether the efficiency of the particular vapor-compression system is increasing or is decreasing, but is incapable of delivering a specific ~oefficient of performance for the system.
SUMMARY OF THE INVE~TIO~
The present invention discloses a coef~icient of performance measuring device in the form of a meter that overcomes the limitations in prior art devices. The davice is relatively inexpensive to build and is capable of on-site measurement, giving instantaneous measurements of the specific coefficient of performance, and does not interrupt the system operation. Unlike other devices suggested for this application, it is not merely diagnos-tic in nature, nor does it give only a relative coeffi-cient o~ performance indication. Rather, it gives an absolute value of the specific operating condition of a heat pump or a vapor-compression system used typically in a residential or commercial cooling application.
The present invention is accomplished by measuring the power supplied to the compressor motor and, in its simplest form, measures four temperatures that are available normally outside of the building in which the vapor-compression system is installed. The four tempera-7~
--~3 tures measured are the input temperature and the outputtemperature at the compressor, along wit~ the temperatures into and out of the expansion valve or expansion means used in the vapor-compression system. With these four temperatures and the electrical power input to the compressor motor, it is possible to continuously compute and display the specific coefficient of performance by means o a meter that has within it a means for storing the losses of a particular type of motor b~ing used to drive the compressor, the typical temperature-entropy curve, and the typical pressure-enthalpy curve of a vapor-compression system utilizing a particular refrigerant. The information as to the motor losses and the particular refrigerant ~an be set into the measuring device which contains a processor means. The various memory means, and the processor means (which contains a micro-processor or microcomputer) is capable of providing absolute values for the specific operating conditions of the mechanical vapor-compression system under test.
In accordance with the present invention, there is provided a specific coefficient of performance measuring device for a mechanical vapor-compression system having a motor, a compressor driven by said motor, inside coil means, outside coil means, and fluid expansion means connected to form said system, including: power transducer means connected to said motor to measure the power supplied to said motor with said power transducer means having an electrical output indicative of the power drawn by said motor; a plurality of temperature sensing means connected to measure temperatures including the temperatures of an inlet and an outlet of said compressor, and an inlet and an outlet of said fluid expan-. ..~
~37~
-~3a-sion means with all of said measured temperatures being represented by electrical signals as outputs from said temperature sensing mean6; power loss storage means to store losses typical of said motor; pressure-enthalpy storage means to store the pressure versus enthalpy characteristics of the mechanical vapor-compression system under test; temperature-entropy storage means to store the temperature versus entropy characteristics of the m~chanical vapor-compression system under test; processor means having a plurality of input means connected to receive signals from said power loss storage means, said pressure-enthalpy storage means, said temperature-entropy storage means, said power transducer means, and said plurality of temperature sensing means; and coefficient of performance output means connec~ed to said processor means to provide a specific coefficient of performance for said system as said system is operating by said processor means determining the power delivered hy said motor and by said processor means continuously determining said coefficient of performance.
In accordance with the present invention, there is furthe.r provided a specific coefficient of performance measuring device for a mechanical vapor-compression system having a motor, a compressor driven by said moto.r, inside coil means, outside coil means, and fluid expansion means connected to form said system, including: power transducer means connected to said motor to measure the power supplied to said motor with said power transducer means having an electrical output indicative of the power drawn by said motor; a plurality of temperature sensing means connected to measure temperatures including the temperatures of an inlet and an k ~{~
-3b outlet of said compressor, and an inlet and an outlet of said fluid expansion means with all of said measured temperatures being represented by electrical signals as outputs from said temperature sensing means; and processor means including output means and having a plurality o:E input means connected to receive signals from said power transducer means, and said plurality of temperature sensing means to provide a specific coefficient of performance for said system as said system is operating by said processor means determining the power delivered by said motor and by said processor means continuously determining said coefficient of performance.
BRIEF DESCRIPTIO~ OF THE DRAWINGS
Figure 1 is a block diagram of a mechanical vapor-compression system with the coefficient of performance meter attached;
Figure 2 is a typical temperature-entropy curve for a mechanical vapor-compression system;
.~
c~~r -~;207~
Figure 3 is a typical pressure-enthalpy curve for a mechanical vapor-compression system, Figure 4 is a block diagram of a microprocessor for use with the invention, and, Figure 5 is a flow chart showing the basic operation of the device.
DESCRIPTION OF THE PREFERRED EMBODIMENT
A mechanical vapor-compression system is disclosed at 10. The mechanical vapor-compression system 10 can be considered as an air conditioning system for a building, or a heat pump for a building. The changeover mechanism for reversing of the system to create a heat pump has not been shown as it is not direc~ly material to the present invention. m e mechanical vapor-compression system 10 includes an electrically operated motor 11, a compressor 12 driven by motor 11, an outlet 13, and an inlet 14. The outlet 13 is connected by a pipe 15 to a coil 16 that has been identified as the outside coil for the present system. The outside coil is connected by a pipe 17 to a fluid expansion means 20 that has been indi-cated as an expansion valve. The fluid expansion means 20 is connected by a pipe 21 to a coil 22 that ha~ been identified as the inside coil for the device. The refrigerant circuit for the system 10 is completed by a pipe 23 which connects the inside coil 22 to the inlet 14 of the compressor 12.
~2~7~5~
Th~ coil 16 has been identified as the outside coil. Coil '~, the fluid expansion means 20, the com-pressor 12, its drive motor 11, and the outlet 13, and the inlet 14 of the compressor 12 are disclosed as being enclosed at 24 in a housing that typically would be exte-rior to a building when the system is used as an air con-ditioning system or as a heat p~p. A second section has been enclosed by the portion indicated at 25 which encloses just the inside coil 22 and the pipiny 21 and 23 that connects the expansion means 20 and the inlet 14 of the refrigerant circuit to the compressor 12. Typically the portion shown at 25 would be enclosed within a fur-nace or air tempering system to provide heating or cooling to a building within which the portion 25 is enclosed. The portion 24 typically would be enclosed in a housing t.hat is exterior to the building being tempera~
ture conditioned, and the entire portion encircled by the dotted portion 24 would be outside in a free air space.
The portions~ 24 and 25 are separated at 26 to show which portions of the system typically would be inside of a building and which portions of the system would be typi-cally outside of the building. It will be understood that the disclosure does not show the reversing mechanism in the event that the system was used as a heat pump. It is merely necessary that it be understood which portions ~z~7ns~
are inside of the building and which are exterior to the building .
To complete the mechanical vapor- compression system, including the invention disclosed as a specific coefficient of performance measuring device, the device itself is disclosed at 30. The coefficient vf perfor-mance measuring device 30 is connected ~y a plurality of electrical conductors to sensors that measure temperature within the system, and to a power transducer. A power transducer is indicated at 31 which is connected by a conductor 32 to the coefficient of performance measuring device 30. Also included are a series of six conductors 33, 34, 35, 36, 37, and 38 which are connected between the coefficient of performance measuring device 30 and a plurality of temperature sensing means connected to various parts of mechanical vapor-compression system 10.
The conductor 33 is connected to a sensor means 43 that is a temperature sensor at the inlet 14 of the compressor 12. The conductor 34 is connected to a temperature sensing means 44 that is physically mounted on the inside coil 22 of the mechanical vapor-compression system. rhe conductor 35 is connected to an outlet side of the fluid expansion means 20 at 45 and is capable of measuring the temperature at that point. The conductor 36 is connected to a temperature sensor 46 that is connected at the inlet side of the fluid expansion means 20, to measure the tem-perature of the pipe 17 as fluid enters the expansion means 20. The conductor 37 is connected to a sensor 47 that is attached in a heat exchange relationship to the surface of the outside coil 16 to measure its temperature during the operation of the system. The system is com-pleted ~y the conductor 38 bei~g connected to a tempera-ture sensor 4~ that is effectively connected to the out-let 13 of the compressor 20 by being connected to the pipe 15 in a heat exchange relationship. The six temper ature sensors can be any type of temperature sensor capa-ble of being attached, clamped or mounted on the system under test. The sensors provide an electrical signal that can be measured.
As can be seen from the arrangement, the coef-ficient of performance device 30 is capable of being connected to the mechanical vapor-compression system 10 to measure parameters of that system without the need to break into the refrigeration piping to measure any spe-cific flow or pressure as a parameter of -the operation.
The sensors 43 through 48 are merely temperature sensors which can be mounted in good heat exchange relationship to the surfaces of the mechanical vapor-compression sys-tem 10. The sensor 31 is a power transducer means that is capable of measuring the power being supplied electri-cally to the motor 11. This could be a clamp-on type of ammeter, or other power measuring device. Further, it is 7~
noted that only one connection is made within the enclo-sure 25 and that i5 to the inside coil 22 at the sensor 44. In certain cases the temperature of the inside coil 22 and the outside coil 16 are not needed, and it can thus be seen that all of the connections can be made within the housing portion 24 which is exterior of a building. This allows the coe~ficient o performance measuring device 30 to be connected to a system without the need to gain access to the building in which the sys-1~ tem provides climate control. T~le operation of the coef-ficient of performance measuring device 30 will be brought out in connection with the balance of the figures of the present disclosure.
Figures 2 and 3 show the pertinent thermodynam-ic states for evaluating the coefficient of performance of a mechanical vapor-compression system on both a temperature-entropy (T-s) and a pressure-enthalpy (P-h) diagram. In Figure 2 the typical temperature-entropy (T-s) diagram is provided in which the temperature in degrees Fahrenheit is compared against enthalpy in Brit-ish thermal units per pound mass. The diagram shows six states (which have been identified as numbers which are circled) ~hat are of interest in connection with the development of the theory o operation of the present device. The balance of Figure 2 has been labeled with ~2(~7(~
_9_ the various states of the liquid and vapor and are believed self-explanatory.
In Figure 3 a typical pressure-enthalpy (P-h) diagram is disclosed wherein the six states are again disclosed as numbers within circles. In the typical pressure-enthalpy diagram the pressure in pounds per square inch absolute is measured against the entropy in British thermal units per pound mass. The diagrams of Figures 2 and 3 are typical and will vary from refriger-ant to refrigerant. As such, a means for storing thisinformation is provided within the coefficient of perfor-mance device 30 as will be brought out below. In the discussion below which develops the theory of operation of the system disclosed in Figure 1, the diagrams of Fig-ures 2 and 3 will be referred to.
- The system coef~icien~ of performance of the mechanical vapor-compression system is defined as the ratio of the heat rejected to the total work input for heating, and as the ratio of the heat absorbed to the total work input for cooling or:
COP h = r 2 h4~ (1) 7~
where:
COPsh = the system coefficient of Performance while heating Wt = the total work input including transport pumps and fans mr ~ the mass flow rate of the refrigerant h2 and h4 are enthalpies of the xefrigerant at states 2 and 4.
COP = r 1 5) (2) where:
CPsC = the system coefficient of performance while cooling h5 is the enthalpy at state 5 The COP of the refrigerant flow circuit is:
h2 - h rh h2 ~ hl (3) where:
20COPrh = the refrigerant coefficient of performance while heating;
hl is the enthalpy at state 1 and ~2~7n5~
COP = COP hl - h rc rh h - h where:
COPrc = the refrigerant coefficient of per-formance while cooling;
The compressor work (Wc) is:
Wc = nWin (5) where:
Win = power to the motor that drives the compressor (directly measurable with a power transducer), n = motor efficiency (a function of load).
The work input to the refrigerant (Wr) is:
Wr = mr (h2 hl~ (6) and, W = W - Q (7) r c amb where:
Qamb = jacket heat loss of the compressor Combining equations (5) and (7) gives the refrigerant flow rate through the compressor as:
Win n ~ Qamb (8) I
~Q7~59 The total electrical power input to the system is given by-Wt Win Wfans Wpumps Wdefrost Wcontrols + l~crank case t9) Combining equations (1) and (8):
COP (Win n ~ Qamb) (h2 4 (lO) sh W (h - h ) Similarly combining equations (2) and (8):
COP (Win n ~ Qamb) (hl 5 (ll) sc W (h - hl) These equations show that once the power inputs, casing loss and compressor motor efficiency are determined, the system coefficient of performance can be calculated knowing states l, 2, 4 and 5. The method of calculating the states is given below.
A microprocessor (shown in Figure ~) will have the relevant properties of the common refrigerants stored in its memory. Thus, with a single selector switch (not shown), the user can address the appropriate tables for the refrigexant that is under study. In the ideal system (no viscous pressure losses; no subcooling and no superheat), we can use the temperatures at states 1, 2, 4 and 5 ~L~(37~i;9 directly to generate the relevant enthalpies.
For instance, state 4 is saturated, thus:
T4 ~ h4 and P4 (12) and h4 = h5 ~13) 5 ~ 5 (14) P5 ~ Pl (15) Pl and Tl ~ hl (16) P4 P2 (17) P2 and T2 ~ h2 (18) Therefore, by usin~ suitably insulated temperature sensors located at the compressor inlet 14 and outlet 13, and across the fluid expansion means 20, the enthalpies at states 1, 2, 4 and 5 can be determined.
Consider the effect of viscous pressure loss in the eva~orator. If a well insulated temperature sensor is installed half-way along the fluid circuit of the condensor, state 6, we can assume that half of the condenser pressure loss occurs between states 5 and 6.
Therefore, since:
T6 ~ P6 (19) 12~ns~
and Pl' = P5 - 2 (P5 ~ P6) (20) rearranging equation (20):
Pl~ = 2 P6 ~ Ps (21) Assuming no significant pressure drop in the super-heat region:
Pl Pl (22) now hl = f (Pl, Tl) (23) Similarly, it ~an be shown for viscous pressure loss in the evaporator:
P2' = 2 P3 - P4 (24) If one considers the viscous pressure loss o the refrigerant gas in the condenser to be negligible, we may write:
P2 = P2 ~ (25 now h2 = f (P~ T2~ (26) Therefore, for mechanical vapor-compression systems presumed to have significant viscous pressure losses, the addition of suitably insulated sensors at states 3 and 6 and the substitution of equations (23) and (26) for equations (16) and (1~) respectively, will yield correct results.
~Z~7~5~
Consider the effect of subcooling. With the system in dynamic operation, sensor 4 will sense the temperature of a saturated liquid or a sub-cooled liquid. If state 4 were a saturated liquid, then:
h4 = f (T4) (27) Thus, knowing only the temperature of state 4, the microprocessor can determine the enthalpy according to an expression in the form of equation (19). If state 4 is a subcooled liquid, then theoretically:
h4 = f (T4~ 4) (28) However, in the subcooled region, pressu~e has little or no effect on the enthalpy, thus the enthalpy at state 4 can always be given by equation (27).
There is some error introduced due to the assumption on the consistency of the pressure drop mechanism in going from two-phase flow to the superheat region at state 1. However, at this time it i.s felt that this error is extremely small and will have little or no effect on the accuracy of the device (for example the pressure drop through the evaporator of a well designed mechanical va~or-compression system will in itself be small).
I
~2~ 5~
-16~
The compressor jacket heat loss can be considered if desired. Essentially, the work input to the shaft during compression that does not go into changing the enthalpy of the refrigerant is dissipated as waste heat. When measuring the coefficient of performance of the mechanical vapor-compression system based on refrigerant measuxements, this energy must be accounted for. Based on data from compressor manufacturers, the microprocessor will be supplied with enough information so the user need only specify the type of compressor and size of the mechanical vapor-compression system for the heat loss term in equations (10) and (11) to be automaticallv calculated.
Since the motor efficiencv relates the power input measured to the actual power delivered to the shaft driving the compressor, it is essential that the valve input to the microprocessor be representative of the actual motor efficiency. There-fore, as was the case with the jacket heat loss, a survey of numerous compressor manufacturers can provide this data and have it stored in the micro-processor so that, upon selection of a particular mechanical vapor-compression system, the appropriate ~5 motor efficiency will be chosen for use in the ~oeffi-cient of performance calculations.
In Figure 4 there is disclosed a microprocessor with connections for the coefficient of performance measuring device 30 with pressure loss using the refrig-erant side analysis method that has been developed. The sensors 44 and 47 (on Figure 1) that are connected to the inside coil 22 and the outside coil 16 are not required if the viscous pressure losses are negligible. Ihe coef~
ficient of performance meter 30 is shown in Figure 4 wherein the sensors 43, 44, 45, 46, 47, 48, and 31 are disclosed as an input to an analog to digital card 60.
This card is connected by a multi-pin ribbon cable 61 to a microprocessor that could be a Motorola lA micro-processor known as a 6802 which has a lK RAM and a 4K
PROM memory for storage of information as indicated~ The microprocessor 62 is connected by a multi-pin power cable 63 to a power supply 64 that is capable of supplying the microprocessor and electronics with the correct power.
Power input to the power supply 64 is shown at conductors 65 and 66 and are of conventional design.
A keypad and displa~ board 70 is provided for input and output of data from the coefficient of perfor-mance device 30 and is interconnected by a multi-pin rib-bon 71 to the analog to digital card 60 and by multi-pin ribbon cable 72 to the input ports of the microprocessor I
~2~
62. This microprocessor arrangement provides the specif-ic coefficient of performance measuring device 30 with the ability to store the power loss characteristics of the motor in a power loss storage means, the pressure versus enthalpy characteristics of the me~hanical vapor-compression system under test in a pressure~enthalpy storage means, the temperature versus entropy characteristics of the mechanical vapor-compression system under test in a temperature-entropy storage means, and Eu~ther provides a processor means wherein a plurality of input means are connected to receive the signals from t~e storage means and from the various temperature sensing means and the power transducer means.
In order to further explain the operation of the present device, the coefficient of per~ormance meter 30 executive flow chart is disclosed in Figure 5. At block 80 the parameters are initialized and at 81 the registers are cleared. The output of 81 is fed to a check start initialization device at 82 which can provide a "no" indication at 83, or can continue on with the sequence at 84. If the sequence is continued at 84, the system checks whether in the heating or cooling mode at 85. m e appropriate mode is verified by the check of the coefficient of performance modes at 86 or 87 for heating and cooling. The modes are properly selected and the 7~
system flows on to ~8 where the selection of the appro-priate refrigerant data is checked. At 90 the sensors (that is the temperature sensors and the power transducer means) are read as is a real time clock. With this information the data flow is to 91 to perForm the calcu-lations based on the operational mode. At 92, if the instantaneous coefficient of performance is available, it can be displayed at 93 or further processed in a check cycle pattern 94 which then indicates a steady state and displays it at 95.
A representation of a speciic coefficient of performance measuring device 30 has been disclosed in a generalized form with the development of theory of operation in a detailed mathematical presentation. ~his can be readily implemented in the microccmputer or micro-processor of Figure 4 when considered with the flow chart of Figure 5. Variations have been disclosed within the presentation showing how a system can be built in a simplified form if certain losses can be neglected.
Various other structural and functional variations would be obvious to one skilled in the art, and the present applicants wish to be limited in the scope of their invention solely by the scope of the appended claims.
BACKGROUND OF THE INVENTION
To measure the coefficient of performance of a mechanical vapor-compression refrigeration system, two S parameters must be known. These parameters are the input power, and the heat rejected (in the case of heating) or the heat absorbed (in the case of cooling). Currently, manufacturers test mechanical vapor-compression systems by measuring input power directly with a power transducer or indirectly with an ammeter, and by measuring the heat rejected or absorbed with a large environmental chamber.
This method allows accurate coefficient of performance measurement, however, it does not lend itsalf to applica-tion in the field, whether in the research laboratory or at a specific site, such as a home in which a heat pump or air conditioning system of the vapor-compression type is installed.
m e need to measure the coefficient of perfor-mance of an air conditioning system or a heat pump has been recognized and is becoming more and more important with the widespread use of heat pumps as an energy effi-cient approach to heating and cooling. Attempts to provide measurements of the coefficient of performance have been undertaken by measurements of certain tempera-.~
n~
tures at a specific installation, but these measurementsallow for only a relative coefficient of performance to be provided. The relative coefficient of performance provides a measure only of whether the efficiency of the particular vapor-compression system is increasing or is decreasing, but is incapable of delivering a specific ~oefficient of performance for the system.
SUMMARY OF THE INVE~TIO~
The present invention discloses a coef~icient of performance measuring device in the form of a meter that overcomes the limitations in prior art devices. The davice is relatively inexpensive to build and is capable of on-site measurement, giving instantaneous measurements of the specific coefficient of performance, and does not interrupt the system operation. Unlike other devices suggested for this application, it is not merely diagnos-tic in nature, nor does it give only a relative coeffi-cient o~ performance indication. Rather, it gives an absolute value of the specific operating condition of a heat pump or a vapor-compression system used typically in a residential or commercial cooling application.
The present invention is accomplished by measuring the power supplied to the compressor motor and, in its simplest form, measures four temperatures that are available normally outside of the building in which the vapor-compression system is installed. The four tempera-7~
--~3 tures measured are the input temperature and the outputtemperature at the compressor, along wit~ the temperatures into and out of the expansion valve or expansion means used in the vapor-compression system. With these four temperatures and the electrical power input to the compressor motor, it is possible to continuously compute and display the specific coefficient of performance by means o a meter that has within it a means for storing the losses of a particular type of motor b~ing used to drive the compressor, the typical temperature-entropy curve, and the typical pressure-enthalpy curve of a vapor-compression system utilizing a particular refrigerant. The information as to the motor losses and the particular refrigerant ~an be set into the measuring device which contains a processor means. The various memory means, and the processor means (which contains a micro-processor or microcomputer) is capable of providing absolute values for the specific operating conditions of the mechanical vapor-compression system under test.
In accordance with the present invention, there is provided a specific coefficient of performance measuring device for a mechanical vapor-compression system having a motor, a compressor driven by said motor, inside coil means, outside coil means, and fluid expansion means connected to form said system, including: power transducer means connected to said motor to measure the power supplied to said motor with said power transducer means having an electrical output indicative of the power drawn by said motor; a plurality of temperature sensing means connected to measure temperatures including the temperatures of an inlet and an outlet of said compressor, and an inlet and an outlet of said fluid expan-. ..~
~37~
-~3a-sion means with all of said measured temperatures being represented by electrical signals as outputs from said temperature sensing mean6; power loss storage means to store losses typical of said motor; pressure-enthalpy storage means to store the pressure versus enthalpy characteristics of the mechanical vapor-compression system under test; temperature-entropy storage means to store the temperature versus entropy characteristics of the m~chanical vapor-compression system under test; processor means having a plurality of input means connected to receive signals from said power loss storage means, said pressure-enthalpy storage means, said temperature-entropy storage means, said power transducer means, and said plurality of temperature sensing means; and coefficient of performance output means connec~ed to said processor means to provide a specific coefficient of performance for said system as said system is operating by said processor means determining the power delivered hy said motor and by said processor means continuously determining said coefficient of performance.
In accordance with the present invention, there is furthe.r provided a specific coefficient of performance measuring device for a mechanical vapor-compression system having a motor, a compressor driven by said moto.r, inside coil means, outside coil means, and fluid expansion means connected to form said system, including: power transducer means connected to said motor to measure the power supplied to said motor with said power transducer means having an electrical output indicative of the power drawn by said motor; a plurality of temperature sensing means connected to measure temperatures including the temperatures of an inlet and an k ~{~
-3b outlet of said compressor, and an inlet and an outlet of said fluid expansion means with all of said measured temperatures being represented by electrical signals as outputs from said temperature sensing means; and processor means including output means and having a plurality o:E input means connected to receive signals from said power transducer means, and said plurality of temperature sensing means to provide a specific coefficient of performance for said system as said system is operating by said processor means determining the power delivered by said motor and by said processor means continuously determining said coefficient of performance.
BRIEF DESCRIPTIO~ OF THE DRAWINGS
Figure 1 is a block diagram of a mechanical vapor-compression system with the coefficient of performance meter attached;
Figure 2 is a typical temperature-entropy curve for a mechanical vapor-compression system;
.~
c~~r -~;207~
Figure 3 is a typical pressure-enthalpy curve for a mechanical vapor-compression system, Figure 4 is a block diagram of a microprocessor for use with the invention, and, Figure 5 is a flow chart showing the basic operation of the device.
DESCRIPTION OF THE PREFERRED EMBODIMENT
A mechanical vapor-compression system is disclosed at 10. The mechanical vapor-compression system 10 can be considered as an air conditioning system for a building, or a heat pump for a building. The changeover mechanism for reversing of the system to create a heat pump has not been shown as it is not direc~ly material to the present invention. m e mechanical vapor-compression system 10 includes an electrically operated motor 11, a compressor 12 driven by motor 11, an outlet 13, and an inlet 14. The outlet 13 is connected by a pipe 15 to a coil 16 that has been identified as the outside coil for the present system. The outside coil is connected by a pipe 17 to a fluid expansion means 20 that has been indi-cated as an expansion valve. The fluid expansion means 20 is connected by a pipe 21 to a coil 22 that ha~ been identified as the inside coil for the device. The refrigerant circuit for the system 10 is completed by a pipe 23 which connects the inside coil 22 to the inlet 14 of the compressor 12.
~2~7~5~
Th~ coil 16 has been identified as the outside coil. Coil '~, the fluid expansion means 20, the com-pressor 12, its drive motor 11, and the outlet 13, and the inlet 14 of the compressor 12 are disclosed as being enclosed at 24 in a housing that typically would be exte-rior to a building when the system is used as an air con-ditioning system or as a heat p~p. A second section has been enclosed by the portion indicated at 25 which encloses just the inside coil 22 and the pipiny 21 and 23 that connects the expansion means 20 and the inlet 14 of the refrigerant circuit to the compressor 12. Typically the portion shown at 25 would be enclosed within a fur-nace or air tempering system to provide heating or cooling to a building within which the portion 25 is enclosed. The portion 24 typically would be enclosed in a housing t.hat is exterior to the building being tempera~
ture conditioned, and the entire portion encircled by the dotted portion 24 would be outside in a free air space.
The portions~ 24 and 25 are separated at 26 to show which portions of the system typically would be inside of a building and which portions of the system would be typi-cally outside of the building. It will be understood that the disclosure does not show the reversing mechanism in the event that the system was used as a heat pump. It is merely necessary that it be understood which portions ~z~7ns~
are inside of the building and which are exterior to the building .
To complete the mechanical vapor- compression system, including the invention disclosed as a specific coefficient of performance measuring device, the device itself is disclosed at 30. The coefficient vf perfor-mance measuring device 30 is connected ~y a plurality of electrical conductors to sensors that measure temperature within the system, and to a power transducer. A power transducer is indicated at 31 which is connected by a conductor 32 to the coefficient of performance measuring device 30. Also included are a series of six conductors 33, 34, 35, 36, 37, and 38 which are connected between the coefficient of performance measuring device 30 and a plurality of temperature sensing means connected to various parts of mechanical vapor-compression system 10.
The conductor 33 is connected to a sensor means 43 that is a temperature sensor at the inlet 14 of the compressor 12. The conductor 34 is connected to a temperature sensing means 44 that is physically mounted on the inside coil 22 of the mechanical vapor-compression system. rhe conductor 35 is connected to an outlet side of the fluid expansion means 20 at 45 and is capable of measuring the temperature at that point. The conductor 36 is connected to a temperature sensor 46 that is connected at the inlet side of the fluid expansion means 20, to measure the tem-perature of the pipe 17 as fluid enters the expansion means 20. The conductor 37 is connected to a sensor 47 that is attached in a heat exchange relationship to the surface of the outside coil 16 to measure its temperature during the operation of the system. The system is com-pleted ~y the conductor 38 bei~g connected to a tempera-ture sensor 4~ that is effectively connected to the out-let 13 of the compressor 20 by being connected to the pipe 15 in a heat exchange relationship. The six temper ature sensors can be any type of temperature sensor capa-ble of being attached, clamped or mounted on the system under test. The sensors provide an electrical signal that can be measured.
As can be seen from the arrangement, the coef-ficient of performance device 30 is capable of being connected to the mechanical vapor-compression system 10 to measure parameters of that system without the need to break into the refrigeration piping to measure any spe-cific flow or pressure as a parameter of -the operation.
The sensors 43 through 48 are merely temperature sensors which can be mounted in good heat exchange relationship to the surfaces of the mechanical vapor-compression sys-tem 10. The sensor 31 is a power transducer means that is capable of measuring the power being supplied electri-cally to the motor 11. This could be a clamp-on type of ammeter, or other power measuring device. Further, it is 7~
noted that only one connection is made within the enclo-sure 25 and that i5 to the inside coil 22 at the sensor 44. In certain cases the temperature of the inside coil 22 and the outside coil 16 are not needed, and it can thus be seen that all of the connections can be made within the housing portion 24 which is exterior of a building. This allows the coe~ficient o performance measuring device 30 to be connected to a system without the need to gain access to the building in which the sys-1~ tem provides climate control. T~le operation of the coef-ficient of performance measuring device 30 will be brought out in connection with the balance of the figures of the present disclosure.
Figures 2 and 3 show the pertinent thermodynam-ic states for evaluating the coefficient of performance of a mechanical vapor-compression system on both a temperature-entropy (T-s) and a pressure-enthalpy (P-h) diagram. In Figure 2 the typical temperature-entropy (T-s) diagram is provided in which the temperature in degrees Fahrenheit is compared against enthalpy in Brit-ish thermal units per pound mass. The diagram shows six states (which have been identified as numbers which are circled) ~hat are of interest in connection with the development of the theory o operation of the present device. The balance of Figure 2 has been labeled with ~2(~7(~
_9_ the various states of the liquid and vapor and are believed self-explanatory.
In Figure 3 a typical pressure-enthalpy (P-h) diagram is disclosed wherein the six states are again disclosed as numbers within circles. In the typical pressure-enthalpy diagram the pressure in pounds per square inch absolute is measured against the entropy in British thermal units per pound mass. The diagrams of Figures 2 and 3 are typical and will vary from refriger-ant to refrigerant. As such, a means for storing thisinformation is provided within the coefficient of perfor-mance device 30 as will be brought out below. In the discussion below which develops the theory of operation of the system disclosed in Figure 1, the diagrams of Fig-ures 2 and 3 will be referred to.
- The system coef~icien~ of performance of the mechanical vapor-compression system is defined as the ratio of the heat rejected to the total work input for heating, and as the ratio of the heat absorbed to the total work input for cooling or:
COP h = r 2 h4~ (1) 7~
where:
COPsh = the system coefficient of Performance while heating Wt = the total work input including transport pumps and fans mr ~ the mass flow rate of the refrigerant h2 and h4 are enthalpies of the xefrigerant at states 2 and 4.
COP = r 1 5) (2) where:
CPsC = the system coefficient of performance while cooling h5 is the enthalpy at state 5 The COP of the refrigerant flow circuit is:
h2 - h rh h2 ~ hl (3) where:
20COPrh = the refrigerant coefficient of performance while heating;
hl is the enthalpy at state 1 and ~2~7n5~
COP = COP hl - h rc rh h - h where:
COPrc = the refrigerant coefficient of per-formance while cooling;
The compressor work (Wc) is:
Wc = nWin (5) where:
Win = power to the motor that drives the compressor (directly measurable with a power transducer), n = motor efficiency (a function of load).
The work input to the refrigerant (Wr) is:
Wr = mr (h2 hl~ (6) and, W = W - Q (7) r c amb where:
Qamb = jacket heat loss of the compressor Combining equations (5) and (7) gives the refrigerant flow rate through the compressor as:
Win n ~ Qamb (8) I
~Q7~59 The total electrical power input to the system is given by-Wt Win Wfans Wpumps Wdefrost Wcontrols + l~crank case t9) Combining equations (1) and (8):
COP (Win n ~ Qamb) (h2 4 (lO) sh W (h - h ) Similarly combining equations (2) and (8):
COP (Win n ~ Qamb) (hl 5 (ll) sc W (h - hl) These equations show that once the power inputs, casing loss and compressor motor efficiency are determined, the system coefficient of performance can be calculated knowing states l, 2, 4 and 5. The method of calculating the states is given below.
A microprocessor (shown in Figure ~) will have the relevant properties of the common refrigerants stored in its memory. Thus, with a single selector switch (not shown), the user can address the appropriate tables for the refrigexant that is under study. In the ideal system (no viscous pressure losses; no subcooling and no superheat), we can use the temperatures at states 1, 2, 4 and 5 ~L~(37~i;9 directly to generate the relevant enthalpies.
For instance, state 4 is saturated, thus:
T4 ~ h4 and P4 (12) and h4 = h5 ~13) 5 ~ 5 (14) P5 ~ Pl (15) Pl and Tl ~ hl (16) P4 P2 (17) P2 and T2 ~ h2 (18) Therefore, by usin~ suitably insulated temperature sensors located at the compressor inlet 14 and outlet 13, and across the fluid expansion means 20, the enthalpies at states 1, 2, 4 and 5 can be determined.
Consider the effect of viscous pressure loss in the eva~orator. If a well insulated temperature sensor is installed half-way along the fluid circuit of the condensor, state 6, we can assume that half of the condenser pressure loss occurs between states 5 and 6.
Therefore, since:
T6 ~ P6 (19) 12~ns~
and Pl' = P5 - 2 (P5 ~ P6) (20) rearranging equation (20):
Pl~ = 2 P6 ~ Ps (21) Assuming no significant pressure drop in the super-heat region:
Pl Pl (22) now hl = f (Pl, Tl) (23) Similarly, it ~an be shown for viscous pressure loss in the evaporator:
P2' = 2 P3 - P4 (24) If one considers the viscous pressure loss o the refrigerant gas in the condenser to be negligible, we may write:
P2 = P2 ~ (25 now h2 = f (P~ T2~ (26) Therefore, for mechanical vapor-compression systems presumed to have significant viscous pressure losses, the addition of suitably insulated sensors at states 3 and 6 and the substitution of equations (23) and (26) for equations (16) and (1~) respectively, will yield correct results.
~Z~7~5~
Consider the effect of subcooling. With the system in dynamic operation, sensor 4 will sense the temperature of a saturated liquid or a sub-cooled liquid. If state 4 were a saturated liquid, then:
h4 = f (T4) (27) Thus, knowing only the temperature of state 4, the microprocessor can determine the enthalpy according to an expression in the form of equation (19). If state 4 is a subcooled liquid, then theoretically:
h4 = f (T4~ 4) (28) However, in the subcooled region, pressu~e has little or no effect on the enthalpy, thus the enthalpy at state 4 can always be given by equation (27).
There is some error introduced due to the assumption on the consistency of the pressure drop mechanism in going from two-phase flow to the superheat region at state 1. However, at this time it i.s felt that this error is extremely small and will have little or no effect on the accuracy of the device (for example the pressure drop through the evaporator of a well designed mechanical va~or-compression system will in itself be small).
I
~2~ 5~
-16~
The compressor jacket heat loss can be considered if desired. Essentially, the work input to the shaft during compression that does not go into changing the enthalpy of the refrigerant is dissipated as waste heat. When measuring the coefficient of performance of the mechanical vapor-compression system based on refrigerant measuxements, this energy must be accounted for. Based on data from compressor manufacturers, the microprocessor will be supplied with enough information so the user need only specify the type of compressor and size of the mechanical vapor-compression system for the heat loss term in equations (10) and (11) to be automaticallv calculated.
Since the motor efficiencv relates the power input measured to the actual power delivered to the shaft driving the compressor, it is essential that the valve input to the microprocessor be representative of the actual motor efficiency. There-fore, as was the case with the jacket heat loss, a survey of numerous compressor manufacturers can provide this data and have it stored in the micro-processor so that, upon selection of a particular mechanical vapor-compression system, the appropriate ~5 motor efficiency will be chosen for use in the ~oeffi-cient of performance calculations.
In Figure 4 there is disclosed a microprocessor with connections for the coefficient of performance measuring device 30 with pressure loss using the refrig-erant side analysis method that has been developed. The sensors 44 and 47 (on Figure 1) that are connected to the inside coil 22 and the outside coil 16 are not required if the viscous pressure losses are negligible. Ihe coef~
ficient of performance meter 30 is shown in Figure 4 wherein the sensors 43, 44, 45, 46, 47, 48, and 31 are disclosed as an input to an analog to digital card 60.
This card is connected by a multi-pin ribbon cable 61 to a microprocessor that could be a Motorola lA micro-processor known as a 6802 which has a lK RAM and a 4K
PROM memory for storage of information as indicated~ The microprocessor 62 is connected by a multi-pin power cable 63 to a power supply 64 that is capable of supplying the microprocessor and electronics with the correct power.
Power input to the power supply 64 is shown at conductors 65 and 66 and are of conventional design.
A keypad and displa~ board 70 is provided for input and output of data from the coefficient of perfor-mance device 30 and is interconnected by a multi-pin rib-bon 71 to the analog to digital card 60 and by multi-pin ribbon cable 72 to the input ports of the microprocessor I
~2~
62. This microprocessor arrangement provides the specif-ic coefficient of performance measuring device 30 with the ability to store the power loss characteristics of the motor in a power loss storage means, the pressure versus enthalpy characteristics of the me~hanical vapor-compression system under test in a pressure~enthalpy storage means, the temperature versus entropy characteristics of the mechanical vapor-compression system under test in a temperature-entropy storage means, and Eu~ther provides a processor means wherein a plurality of input means are connected to receive the signals from t~e storage means and from the various temperature sensing means and the power transducer means.
In order to further explain the operation of the present device, the coefficient of per~ormance meter 30 executive flow chart is disclosed in Figure 5. At block 80 the parameters are initialized and at 81 the registers are cleared. The output of 81 is fed to a check start initialization device at 82 which can provide a "no" indication at 83, or can continue on with the sequence at 84. If the sequence is continued at 84, the system checks whether in the heating or cooling mode at 85. m e appropriate mode is verified by the check of the coefficient of performance modes at 86 or 87 for heating and cooling. The modes are properly selected and the 7~
system flows on to ~8 where the selection of the appro-priate refrigerant data is checked. At 90 the sensors (that is the temperature sensors and the power transducer means) are read as is a real time clock. With this information the data flow is to 91 to perForm the calcu-lations based on the operational mode. At 92, if the instantaneous coefficient of performance is available, it can be displayed at 93 or further processed in a check cycle pattern 94 which then indicates a steady state and displays it at 95.
A representation of a speciic coefficient of performance measuring device 30 has been disclosed in a generalized form with the development of theory of operation in a detailed mathematical presentation. ~his can be readily implemented in the microccmputer or micro-processor of Figure 4 when considered with the flow chart of Figure 5. Variations have been disclosed within the presentation showing how a system can be built in a simplified form if certain losses can be neglected.
Various other structural and functional variations would be obvious to one skilled in the art, and the present applicants wish to be limited in the scope of their invention solely by the scope of the appended claims.
Claims (9)
1. A specific coefficient of performance measuring device for a mechanical vapor-compression system having a motor, a compressor driven by said motor, inside coil means, outside coil means, and fluid expansion means connected to form said system, including: power trans-ducer means connected to said motor to measure the power supplied to said motor with said power transducer means having an electrical output indicative of the power drawn by said motor; a plurality of temperature sensing means connected to measure temperatures including the tempera-tures of an inlet and an outlet of said compressor, and an inlet and an outlet of said fluid expansion means with all of said measured temperatures being represented by electrical signals as outputs from said temperature sensing means; power loss storage means to store losses typical of said motor pressure-enthalpy storage means to store the pressure versus enthalpy characteristics of the mechanical vapor-compression system under test temperature-entropy storage means to store the tempera-ture versus entropy characteristics of the mechanical vapor-compression system under test; processor means having a plurality of input means connected to receive signals from said power loss storage means, said pressure-enthalpy storage means, said temperature-entropy storage means, said power transducer means, and said plu-rality of temperature sensing means: and coefficient of performance output means connected to said processor means to provide a specific coefficient of performance for said system as said system is operating by said pro-cessor means determining the power delivered by said motor and by said processor means continuously determin-ing said coefficient of performance.
2. A specific coefficient of performance measuring device as disclosed in claim 1 wherein said power loss storage means, said pressure-enthalpy storage means, said temperature-entropy storage means, and said processor means form a portable coefficient of performance meter which is capable of being connected by said power trans-ducer means to said motor, and by said temperature sensing means to said compressor inlet and outlet and said fluid expansion means inlet and outlet at a location which is proximately to said outside coil means and with-out the need to have access to said inside coil means.
3. A specific coefficient of performance measuring device as disclosed in claim 2 wherein said processor means, said power loss storage means, said pressure-enthalpy storage means, and said temperature-entropy storage means form part of a micro-processor.
4. A specific coefficient of performance measuring device as disclosed in claim 1 wherein said plurality of temperature sensing means are individual temperature responsive sensors that are attached external to said inlets and outlets of said compressor and said fluid expansion means.
5. A specific coefficient of performance measuring device as disclosed in claim 4 wherein said processor means, said power loss storage means, said pressure-enthalpy storage means, and said temperature-entropy storage means form part of a micro-processor.
6. A specific coefficient of performance measuring device as disclosed in claim 1 wherein said plurality of temperature sensing means further includes means to sense the temperature of said inside coil means and said outside coil means.
7. A specific coefficient of performance measuring device as disclosed in claim 6 wherein said power loss storage means, said pressure-enthalpy storage means, said temperature-entropy storage means, and said processor means form a portable coefficient of performance meter that is capable of being connected by said power trans-ducer means to said motor, and by said temperature sensing means to said compressor inlet and outlet, said indoor and outdoor coil means, and to said fluid expan-sion means inlet and outlet at a location wherein said mechanical vapor-compression system is installed.
8. A specific coefficient of performance measuring device as disclosed in claim 7 wherein said plurality of temperature sensing means are individual temperature responsive sensors that are attached external to said inlets and outlets of said compressor, to said inside and outside coil means, and to said inlet and outlet of said fluid expansion means.
9. A specific coefficient of performance measuring device for a mechanical vapor-compression system having a motor, a compressor driven by said motor, inside coil means, outside coil means, and fluid expansion means connected to form said system, including: power trans-ducer means connected to said motor to measure the power supplied to said motor with said power transducer means having an electrical output indicative of the power drawn by said motor; a plurality of temperature sensing means connected to measure temperatures including the tempera-tures of an inlet and an outlet of said compressor, and an inlet and an outlet of said fluid expansion means with all of said measured temperatures being represented by electrical signals as outputs from said temperature sensing means; and processor means including output means and having a plurality of input means connected to receive signals from said power transducer means, and said plurality of temperature sensing means to provide a specific coefficient of performance for said system as said system is operating by said processor means deter-mining the power delivered by said motor and by said pro-cessor means continuously determining said coefficient of performance.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US06/401,993 US4510576A (en) | 1982-07-26 | 1982-07-26 | Specific coefficient of performance measuring device |
| US401,993 | 1982-07-26 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1207059A true CA1207059A (en) | 1986-07-02 |
Family
ID=23590103
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000433137A Expired CA1207059A (en) | 1982-07-26 | 1983-07-25 | Specific coefficient of performance measuring device |
Country Status (4)
| Country | Link |
|---|---|
| US (1) | US4510576A (en) |
| EP (1) | EP0100210A3 (en) |
| JP (1) | JPS59104052A (en) |
| CA (1) | CA1207059A (en) |
Families Citing this family (143)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| SE439063B (en) * | 1983-06-02 | 1985-05-28 | Henrik Sven Enstrom | PROCEDURE AND DEVICE FOR TESTING AND PERFORMANCE MONITORING IN HEAT PUMPS AND COOLING INSTALLATIONS |
| DE3335862A1 (en) * | 1983-10-03 | 1985-04-18 | Robert Bosch Gmbh, 7000 Stuttgart | HYDROSTATIC MACHINE (PUMP OR MOTOR) |
| EP0159152A1 (en) * | 1984-03-26 | 1985-10-23 | Maurice Alan Yates | Protection for hydraulic machines |
| US4574871A (en) * | 1984-05-07 | 1986-03-11 | Parkinson David W | Heat pump monitor apparatus for fault detection in a heat pump system |
| US4768346A (en) * | 1987-08-26 | 1988-09-06 | Honeywell Inc. | Determining the coefficient of performance of a refrigeration system |
| US4885914A (en) * | 1987-10-05 | 1989-12-12 | Honeywell Inc. | Coefficient of performance deviation meter for vapor compression type refrigeration systems |
| US4798055A (en) * | 1987-10-28 | 1989-01-17 | Kent-Moore Corporation | Refrigeration system analyzer |
| US4787554A (en) * | 1988-02-01 | 1988-11-29 | Honeywell Inc. | Firing rate control system for a fuel burner |
| US4811567A (en) * | 1988-03-03 | 1989-03-14 | General Electric Company | Method for testing the operability of a refrigerant system |
| US5020007A (en) * | 1988-03-10 | 1991-05-28 | Wu Samuel C | Method for monitoring the health of physical systems producing waste heat |
| US5009076A (en) * | 1990-03-08 | 1991-04-23 | Temperature Engineering Corp. | Refrigerant loss monitor |
| GB9023422D0 (en) * | 1990-10-27 | 1990-12-12 | Air Technology Limited | Compressor monitoring system |
| US5083438A (en) * | 1991-03-01 | 1992-01-28 | Mcmullin Larry D | Chiller monitoring system |
| DE4124363C2 (en) * | 1991-07-23 | 1994-02-03 | Daimler Benz Ag | Procedure for monitoring the refrigerant level in a refrigeration system |
| US5651667A (en) * | 1991-10-11 | 1997-07-29 | Helix Technology Corporation | Cryopump synchronous motor load monitor |
| US5203179A (en) * | 1992-03-04 | 1993-04-20 | Ecoair Corporation | Control system for an air conditioning/refrigeration system |
| US5381669A (en) * | 1993-07-21 | 1995-01-17 | Copeland Corporation | Overcharge-undercharge diagnostic system for air conditioner controller |
| US5666815A (en) * | 1994-11-18 | 1997-09-16 | Cooper Instrument Corporation | Method and apparatus for calculating super heat in an air conditioning system |
| US5628201A (en) * | 1995-04-03 | 1997-05-13 | Copeland Corporation | Heating and cooling system with variable capacity compressor |
| US5623834A (en) * | 1995-05-03 | 1997-04-29 | Copeland Corporation | Diagnostics for a heating and cooling system |
| EP0837309A3 (en) * | 1996-10-18 | 1999-03-10 | SANYO ELECTRIC Co., Ltd. | Method and system for testing performance of refrigeration units |
| US5765378A (en) * | 1996-12-31 | 1998-06-16 | Helix Technology Corporation | Method and apparatus for detecting a loss of differential pressure in a cryogenic refrigerator |
| US6128910A (en) * | 1997-02-06 | 2000-10-10 | Federal Air Conditioning Technologies, Inc. | Diagnostic unit for an air conditioning system |
| KR100286258B1 (en) * | 1998-02-03 | 2001-05-02 | 윤종용 | Method and system for measuring quantity of consumption power to refrigerator |
| CA2284234C (en) * | 1998-10-01 | 2003-09-16 | Samsung Electronics Co., Ltd. | Method and apparatus for predicting power consumption of refrigerator having defrosting heater |
| US6505475B1 (en) | 1999-08-20 | 2003-01-14 | Hudson Technologies Inc. | Method and apparatus for measuring and improving efficiency in refrigeration systems |
| US6272868B1 (en) * | 2000-03-15 | 2001-08-14 | Carrier Corporation | Method and apparatus for indicating condenser coil performance on air-cooled chillers |
| US6532754B2 (en) * | 2001-04-25 | 2003-03-18 | American Standard International Inc. | Method of optimizing and rating a variable speed chiller for operation at part load |
| US6892546B2 (en) * | 2001-05-03 | 2005-05-17 | Emerson Retail Services, Inc. | System for remote refrigeration monitoring and diagnostics |
| US6668240B2 (en) * | 2001-05-03 | 2003-12-23 | Emerson Retail Services Inc. | Food quality and safety model for refrigerated food |
| US6658373B2 (en) * | 2001-05-11 | 2003-12-02 | Field Diagnostic Services, Inc. | Apparatus and method for detecting faults and providing diagnostics in vapor compression cycle equipment |
| US6701725B2 (en) | 2001-05-11 | 2004-03-09 | Field Diagnostic Services, Inc. | Estimating operating parameters of vapor compression cycle equipment |
| US6973410B2 (en) | 2001-05-15 | 2005-12-06 | Chillergy Systems, Llc | Method and system for evaluating the efficiency of an air conditioning apparatus |
| DE10217974B4 (en) * | 2002-04-22 | 2004-09-16 | Danfoss A/S | Method for evaluating an unmeasured operating variable in a refrigeration system |
| DE10217975B4 (en) * | 2002-04-22 | 2004-08-19 | Danfoss A/S | Method for detecting changes in a first media stream of a heat or cold transport medium in a refrigeration system |
| FR2840259B1 (en) * | 2002-05-31 | 2004-08-27 | Valeo Climatisation | VEHICLE AIR CONDITIONING SYSTEM PROVIDED WITH AN ELECTRONIC CONTROL DEVICE |
| DE60309181T2 (en) * | 2002-07-08 | 2007-08-30 | Danfoss A/S | METHOD AND DEVICE FOR DISCOVERING FLASH GAS |
| US6973793B2 (en) * | 2002-07-08 | 2005-12-13 | Field Diagnostic Services, Inc. | Estimating evaporator airflow in vapor compression cycle cooling equipment |
| FR2845035B1 (en) * | 2002-09-27 | 2004-12-24 | Valeo Climatisation | AIR CONDITIONING SYSTEM COMPRISING AN ELECTRONIC CONTROL DEVICE |
| WO2004036170A1 (en) * | 2002-10-15 | 2004-04-29 | Danfoss A/S | A method and a device for detecting an abnormality of a heat exchanger, and the use of such a device |
| US6889173B2 (en) * | 2002-10-31 | 2005-05-03 | Emerson Retail Services Inc. | System for monitoring optimal equipment operating parameters |
| US6713986B1 (en) | 2002-11-26 | 2004-03-30 | Energy Savers International | Controller for air conditioners and heat pumps |
| US8463441B2 (en) | 2002-12-09 | 2013-06-11 | Hudson Technologies, Inc. | Method and apparatus for optimizing refrigeration systems |
| US7490477B2 (en) * | 2003-04-30 | 2009-02-17 | Emerson Retail Services, Inc. | System and method for monitoring a condenser of a refrigeration system |
| AU2008202088B2 (en) * | 2003-04-30 | 2010-11-25 | Emerson Climate Technologies Retail Solutions, Inc. | Predictive maintenance and equipment monitoring for a refrigeration system |
| US7000413B2 (en) * | 2003-06-26 | 2006-02-21 | Carrier Corporation | Control of refrigeration system to optimize coefficient of performance |
| WO2005022049A2 (en) * | 2003-08-25 | 2005-03-10 | Computer Process Controls, Inc. | Refrigeration control system |
| US20050061008A1 (en) * | 2003-09-24 | 2005-03-24 | A. Ben-Nakhi | Method and apparatus for monitoring an air conditioning / refrigeration unit |
| US7290989B2 (en) * | 2003-12-30 | 2007-11-06 | Emerson Climate Technologies, Inc. | Compressor protection and diagnostic system |
| US7412842B2 (en) | 2004-04-27 | 2008-08-19 | Emerson Climate Technologies, Inc. | Compressor diagnostic and protection system |
| US7275377B2 (en) | 2004-08-11 | 2007-10-02 | Lawrence Kates | Method and apparatus for monitoring refrigerant-cycle systems |
| US8109104B2 (en) * | 2004-08-25 | 2012-02-07 | York International Corporation | System and method for detecting decreased performance in a refrigeration system |
| US20060137369A1 (en) * | 2004-12-27 | 2006-06-29 | Carrier Corporation | Single sensor three-step refrigerant charge indicator |
| US20060138771A1 (en) * | 2004-12-27 | 2006-06-29 | Carrier Corporation | Braze-free connector for joining a pair of flow lines |
| US7712319B2 (en) | 2004-12-27 | 2010-05-11 | Carrier Corporation | Refrigerant charge adequacy gauge |
| US7472557B2 (en) * | 2004-12-27 | 2009-01-06 | Carrier Corporation | Automatic refrigerant charging apparatus |
| US7610765B2 (en) * | 2004-12-27 | 2009-11-03 | Carrier Corporation | Refrigerant charge status indication method and device |
| US20060138772A1 (en) * | 2004-12-27 | 2006-06-29 | Carrier Corporation | Braze-free connector |
| US7552596B2 (en) * | 2004-12-27 | 2009-06-30 | Carrier Corporation | Dual thermochromic liquid crystal temperature sensing for refrigerant charge indication |
| WO2006091521A2 (en) * | 2005-02-21 | 2006-08-31 | Computer Process Controls, Inc. | Enterprise control and monitoring system |
| US7419192B2 (en) * | 2005-07-13 | 2008-09-02 | Carrier Corporation | Braze-free connector utilizing a sealant coated ferrule |
| US7203077B2 (en) * | 2005-07-20 | 2007-04-10 | General Atomics Electronic Systems, Inc. | Resonant charge power supply topology for high pulse rate pulsed power systems |
| US7594407B2 (en) | 2005-10-21 | 2009-09-29 | Emerson Climate Technologies, Inc. | Monitoring refrigerant in a refrigeration system |
| US7752854B2 (en) * | 2005-10-21 | 2010-07-13 | Emerson Retail Services, Inc. | Monitoring a condenser in a refrigeration system |
| US7596959B2 (en) | 2005-10-21 | 2009-10-06 | Emerson Retail Services, Inc. | Monitoring compressor performance in a refrigeration system |
| US7665315B2 (en) * | 2005-10-21 | 2010-02-23 | Emerson Retail Services, Inc. | Proofing a refrigeration system operating state |
| US20070089435A1 (en) * | 2005-10-21 | 2007-04-26 | Abtar Singh | Predicting maintenance in a refrigeration system |
| US7752853B2 (en) | 2005-10-21 | 2010-07-13 | Emerson Retail Services, Inc. | Monitoring refrigerant in a refrigeration system |
| US20070089436A1 (en) * | 2005-10-21 | 2007-04-26 | Abtar Singh | Monitoring refrigerant in a refrigeration system |
| US20070093732A1 (en) * | 2005-10-26 | 2007-04-26 | David Venturi | Vibroacoustic sound therapeutic system and method |
| CN101400955B (en) * | 2006-03-23 | 2012-06-27 | 大金工业株式会社 | Refrigeration system, and analyzer of refrigeration system |
| US8590325B2 (en) * | 2006-07-19 | 2013-11-26 | Emerson Climate Technologies, Inc. | Protection and diagnostic module for a refrigeration system |
| US20080216494A1 (en) | 2006-09-07 | 2008-09-11 | Pham Hung M | Compressor data module |
| US20080066474A1 (en) * | 2006-09-20 | 2008-03-20 | Michael Ramey Porter | Refrigeration system energy efficiency enhancement using microsystems |
| WO2008079108A1 (en) * | 2006-12-20 | 2008-07-03 | Carrier Corporation | Refrigerant charge indication |
| WO2008079111A1 (en) * | 2006-12-20 | 2008-07-03 | Carrier Corporation | Method for determining refrigerant charge |
| US9305405B2 (en) * | 2007-06-26 | 2016-04-05 | Omnitracs, Llc | Reefer fuel tax reporting for the transport industry |
| US20090037142A1 (en) | 2007-07-30 | 2009-02-05 | Lawrence Kates | Portable method and apparatus for monitoring refrigerant-cycle systems |
| US8393169B2 (en) | 2007-09-19 | 2013-03-12 | Emerson Climate Technologies, Inc. | Refrigeration monitoring system and method |
| US9140728B2 (en) | 2007-11-02 | 2015-09-22 | Emerson Climate Technologies, Inc. | Compressor sensor module |
| US8160827B2 (en) | 2007-11-02 | 2012-04-17 | Emerson Climate Technologies, Inc. | Compressor sensor module |
| JP5394047B2 (en) * | 2007-11-26 | 2014-01-22 | 高砂熱学工業株式会社 | Method and apparatus for measuring cooling capacity of air conditioning system by package type air conditioner |
| US20090252845A1 (en) * | 2008-04-03 | 2009-10-08 | Southwick Kenneth J | Collider chamber apparatus and method of use |
| DE102008038429A1 (en) * | 2008-08-19 | 2010-02-25 | Erwin Dietz | Heat pump system operating method for air conditioning e.g. building, involves determining coefficient of performance, performance number, efficiency or analysis of refrigerant based on mass flow of refrigerant |
| DE102008061631A1 (en) * | 2008-12-11 | 2010-06-17 | Emerson Electric Gmbh & Co. Ohg | Method for determining the coefficient of performance of a refrigerating machine |
| US20100187320A1 (en) * | 2009-01-29 | 2010-07-29 | Southwick Kenneth J | Methods and systems for recovering and redistributing heat |
| CN101545880B (en) * | 2009-04-30 | 2011-11-16 | 上海交通大学 | Device for measuring trans-critical cycle heat exchange of CO2-oil mixture |
| BRPI1014993A8 (en) | 2009-05-29 | 2016-10-18 | Emerson Retail Services Inc | system and method for monitoring and evaluating equipment operating parameter modifications |
| DE102010050057A1 (en) * | 2010-10-29 | 2012-05-03 | Robert Bosch Gmbh | Method for controlling a heat pump system |
| US8646286B2 (en) * | 2010-12-30 | 2014-02-11 | Pdx Technologies Llc | Refrigeration system controlled by refrigerant quality within evaporator |
| CA2934860C (en) | 2011-02-28 | 2018-07-31 | Emerson Electric Co. | Residential solutions hvac monitoring and diagnosis |
| US9759465B2 (en) | 2011-12-27 | 2017-09-12 | Carrier Corporation | Air conditioner self-charging and charge monitoring system |
| US8964338B2 (en) | 2012-01-11 | 2015-02-24 | Emerson Climate Technologies, Inc. | System and method for compressor motor protection |
| US9480177B2 (en) | 2012-07-27 | 2016-10-25 | Emerson Climate Technologies, Inc. | Compressor protection module |
| US9310439B2 (en) | 2012-09-25 | 2016-04-12 | Emerson Climate Technologies, Inc. | Compressor having a control and diagnostic module |
| US9417638B2 (en) * | 2012-12-20 | 2016-08-16 | Automotive Research & Testing Center | Intelligent thermostatic control method and device for an air conditioner blowing cold and hot air |
| US9958190B2 (en) | 2013-01-24 | 2018-05-01 | Advantek Consulting Engineering, Inc. | Optimizing energy efficiency ratio feedback control for direct expansion air-conditioners and heat pumps |
| US9574810B1 (en) | 2013-01-24 | 2017-02-21 | Advantek Consulting Engineering, Inc. | Optimizing energy efficiency ratio feedback control for direct expansion air-conditioners and heat pumps |
| FR3001527B1 (en) * | 2013-01-28 | 2017-08-11 | Schneider Electric Ind Sas | METHOD FOR DIAGNOSING A HEATING, VENTILATION AND AIR CONDITIONING MACHINE |
| US9551504B2 (en) | 2013-03-15 | 2017-01-24 | Emerson Electric Co. | HVAC system remote monitoring and diagnosis |
| CA2904734C (en) | 2013-03-15 | 2018-01-02 | Emerson Electric Co. | Hvac system remote monitoring and diagnosis |
| US9803902B2 (en) | 2013-03-15 | 2017-10-31 | Emerson Climate Technologies, Inc. | System for refrigerant charge verification using two condenser coil temperatures |
| US9765979B2 (en) | 2013-04-05 | 2017-09-19 | Emerson Climate Technologies, Inc. | Heat-pump system with refrigerant charge diagnostics |
| EP2998667B1 (en) * | 2014-09-17 | 2020-11-25 | Hochschule Biberach | A method, an apparatus and a computer programm product for evaluating the energy efficiency of a refrigeration machine and/or heat pump |
| WO2016118914A1 (en) * | 2015-01-22 | 2016-07-28 | Aquanomix, Llc | Water system efficiency |
| US11867417B2 (en) | 2017-02-09 | 2024-01-09 | James Eric Taylor | On-site controller for an HVAC system |
| CN106871357A (en) * | 2017-02-28 | 2017-06-20 | 青岛海尔空调电子有限公司 | A kind of air-conditioner managing device and the air-conditioner with the managing device |
| CN106949611A (en) * | 2017-02-28 | 2017-07-14 | 青岛海尔空调电子有限公司 | A kind of air-conditioner managing device and the air-conditioner with the managing device |
| CN106839323A (en) * | 2017-02-28 | 2017-06-13 | 青岛海尔空调电子有限公司 | A kind of air-conditioner managing device and the air-conditioner with the managing device |
| US11105689B2 (en) * | 2017-03-09 | 2021-08-31 | Keithley Instruments, Llc | Temperature and heat map system |
| CN107328056A (en) * | 2017-08-31 | 2017-11-07 | 广东美的制冷设备有限公司 | Air conditioner and its efficiency computational methods |
| CN107576008A (en) * | 2017-08-31 | 2018-01-12 | 广东美的制冷设备有限公司 | Air conditioner and its efficiency computational methods |
| CN107388522A (en) * | 2017-08-31 | 2017-11-24 | 广东美的制冷设备有限公司 | Air conditioner and its efficiency computational methods |
| CN107388519A (en) * | 2017-08-31 | 2017-11-24 | 广东美的制冷设备有限公司 | Air conditioner and its efficiency computational methods |
| CN107388515A (en) * | 2017-08-31 | 2017-11-24 | 广东美的制冷设备有限公司 | Air conditioner and its efficiency computational methods |
| CN107514770A (en) * | 2017-08-31 | 2017-12-26 | 广东美的制冷设备有限公司 | Air conditioner and its efficiency computational methods |
| CN107367037A (en) * | 2017-08-31 | 2017-11-21 | 广东美的制冷设备有限公司 | Air conditioner and its efficiency computational methods |
| CN107314514A (en) * | 2017-08-31 | 2017-11-03 | 广东美的制冷设备有限公司 | Air conditioner and its efficiency computational methods |
| CN107388512A (en) * | 2017-08-31 | 2017-11-24 | 广东美的制冷设备有限公司 | Air conditioner and its efficiency computational methods |
| CN107328055A (en) * | 2017-08-31 | 2017-11-07 | 广东美的制冷设备有限公司 | Air conditioner and its efficiency computational methods |
| CN107367032A (en) * | 2017-08-31 | 2017-11-21 | 广东美的制冷设备有限公司 | Air conditioner and its efficiency computational methods |
| CN107514764A (en) * | 2017-08-31 | 2017-12-26 | 广东美的制冷设备有限公司 | Air conditioner and its efficiency computational methods |
| CN107314513A (en) * | 2017-08-31 | 2017-11-03 | 广东美的制冷设备有限公司 | Air conditioner and its efficiency computational methods |
| CN107328038A (en) * | 2017-08-31 | 2017-11-07 | 广东美的制冷设备有限公司 | Air conditioner and its efficiency computational methods |
| CN107504649A (en) * | 2017-08-31 | 2017-12-22 | 广东美的制冷设备有限公司 | Air conditioner and its efficiency computational methods |
| CN107525240A (en) * | 2017-08-31 | 2017-12-29 | 广东美的制冷设备有限公司 | Air conditioner and its efficiency computational methods |
| CN107514771A (en) * | 2017-08-31 | 2017-12-26 | 广东美的制冷设备有限公司 | Air conditioner and its efficiency computational methods |
| CN107514758A (en) * | 2017-08-31 | 2017-12-26 | 广东美的制冷设备有限公司 | Air conditioner and its efficiency computational methods |
| CN107388520A (en) * | 2017-08-31 | 2017-11-24 | 广东美的制冷设备有限公司 | Air conditioner and its efficiency computational methods |
| CN107328052A (en) * | 2017-08-31 | 2017-11-07 | 广东美的制冷设备有限公司 | Air conditioner and its efficiency computational methods |
| CN107514765A (en) * | 2017-08-31 | 2017-12-26 | 广东美的制冷设备有限公司 | Air conditioner and its efficiency computational methods |
| CN107328050A (en) * | 2017-08-31 | 2017-11-07 | 广东美的制冷设备有限公司 | Air conditioner and its efficiency computational methods |
| CN107490146A (en) * | 2017-08-31 | 2017-12-19 | 广东美的制冷设备有限公司 | Air conditioner and its efficiency computational methods |
| CN107490139A (en) * | 2017-08-31 | 2017-12-19 | 广东美的制冷设备有限公司 | Air conditioner and its efficiency computational methods |
| CN107504651A (en) * | 2017-08-31 | 2017-12-22 | 广东美的制冷设备有限公司 | Air conditioner and its efficiency computational methods |
| CN107388517A (en) * | 2017-08-31 | 2017-11-24 | 广东美的制冷设备有限公司 | Air conditioner and its efficiency computational methods |
| CN107490140A (en) * | 2017-08-31 | 2017-12-19 | 广东美的制冷设备有限公司 | Air conditioner and its efficiency computational methods |
| CN107388521A (en) * | 2017-08-31 | 2017-11-24 | 广东美的制冷设备有限公司 | Air conditioner and its efficiency computational methods |
| CN107388523A (en) * | 2017-08-31 | 2017-11-24 | 广东美的制冷设备有限公司 | Air conditioner and its efficiency computational methods |
| CN114322265A (en) * | 2017-08-31 | 2022-04-12 | 广东美的制冷设备有限公司 | Air conditioner and energy efficiency calculation method thereof |
| CN107388518A (en) * | 2017-08-31 | 2017-11-24 | 广东美的制冷设备有限公司 | Air conditioner and its efficiency computational methods |
| CN107490147A (en) * | 2017-08-31 | 2017-12-19 | 广东美的制冷设备有限公司 | Air conditioner and its efficiency computational methods |
| CN112856873A (en) * | 2021-01-18 | 2021-05-28 | 苏州龙雨电子设备有限公司 | Equipment for accurately controlling gas temperature |
Family Cites Families (16)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3082951A (en) * | 1953-07-01 | 1963-03-26 | Univ Columbia | Method for calculating performance of refrigeration apparatus |
| US3555251A (en) * | 1967-12-06 | 1971-01-12 | Honeywell Inc | Optimizing system for a plurality of temperature conditioning apparatuses |
| US3707851A (en) * | 1970-10-28 | 1973-01-02 | Mach Ice Co | Refrigeration system efficiency monitor |
| US3736765A (en) * | 1972-01-05 | 1973-06-05 | Gen Electric | Appliance including electric diagnosis means |
| US3873817A (en) * | 1972-05-03 | 1975-03-25 | Westinghouse Electric Corp | On-line monitoring of steam turbine performance |
| US3946573A (en) * | 1974-08-22 | 1976-03-30 | Whirlpool Corporation | Electrical diagnostic system for refrigeration apparatus |
| DE2543237C3 (en) * | 1975-09-27 | 1980-06-26 | Werner Dipl.-Ing. 8886 Wittislingen Hoefflinger | Method and device for thermodynamic efficiency measurement on hydrostatic displacement machines |
| US4038061A (en) * | 1975-12-29 | 1977-07-26 | Heil-Quaker Corporation | Air conditioner control |
| US4114448A (en) * | 1976-09-13 | 1978-09-19 | Merritt Joseph E | Servicing apparatus |
| US4146085A (en) * | 1977-10-03 | 1979-03-27 | Borg-Warner Corporation | Diagnostic system for heat pump |
| US4186563A (en) * | 1978-04-24 | 1980-02-05 | General Electric Company | Cooling efficiency meter circuit for an air conditioner |
| US4217761A (en) * | 1978-09-28 | 1980-08-19 | Cornaire James L | Heat pump output indicator |
| US4306293A (en) * | 1979-08-30 | 1981-12-15 | Marathe Sharad M | Energy monitoring system |
| JPS5685507A (en) * | 1979-12-17 | 1981-07-11 | Hitachi Ltd | Monitoring method of performance of steam turbine plant |
| US4381549A (en) * | 1980-10-14 | 1983-04-26 | Trane Cac, Inc. | Automatic fault diagnostic apparatus for a heat pump air conditioning system |
| US4432232A (en) * | 1982-05-18 | 1984-02-21 | The United States Of America As Represented By The United States Department Of Energy | Device and method for measuring the coefficient of performance of a heat pump |
-
1982
- 1982-07-26 US US06/401,993 patent/US4510576A/en not_active Expired - Lifetime
-
1983
- 1983-07-21 EP EP83304237A patent/EP0100210A3/en not_active Withdrawn
- 1983-07-25 CA CA000433137A patent/CA1207059A/en not_active Expired
- 1983-07-26 JP JP58136653A patent/JPS59104052A/en active Pending
Also Published As
| Publication number | Publication date |
|---|---|
| US4510576A (en) | 1985-04-09 |
| EP0100210A2 (en) | 1984-02-08 |
| JPS59104052A (en) | 1984-06-15 |
| EP0100210A3 (en) | 1986-07-30 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CA1207059A (en) | Specific coefficient of performance measuring device | |
| US6701725B2 (en) | Estimating operating parameters of vapor compression cycle equipment | |
| JP2997487B2 (en) | Refrigeration apparatus and method for indicating amount of refrigerant in refrigeration apparatus | |
| US9261542B1 (en) | Energy efficiency ratio meter for direct expansion air-conditioners and heat pumps | |
| US4878355A (en) | Method and apparatus for improving cooling of a compressor element in an air conditioning system | |
| US5079930A (en) | Apparatus and method for monitoring refrigeration system | |
| US6973793B2 (en) | Estimating evaporator airflow in vapor compression cycle cooling equipment | |
| KR100776324B1 (en) | Monitoring system using equipment for measuring automatically refrigerator performance | |
| US5709094A (en) | Air conditioner control apparatus based on coolant type detection | |
| US8775123B2 (en) | Method for determination of the coefficient of performanace of a refrigerating machine | |
| US20060041335A9 (en) | Apparatus and method for servicing vapor compression cycle equipment | |
| EP0693663A2 (en) | Control-information detecting apparatus for a refrigeration air-conditioner using a non-azeotrope refrigerant | |
| Lumpkin et al. | Two-phase injected and vapor-injected compression: Experimental results and mapping correlation for a R-407C scroll compressor | |
| CN101821508A (en) | Variable speed compressor protection system and method | |
| Enteria et al. | Performance evaluation of the variable refrigerant flow (VRF) air-conditioning system subjected to partial and unbalanced thermal loadings | |
| JP3560497B2 (en) | Refrigeration compressor test equipment | |
| Ng et al. | The role of internal dissipation and process average temperature in chiller performance and diagnostics | |
| Votsis et al. | Dynamic characteristics of an air-to-water heat-pump system | |
| Rohleder | Experimental Analysis of Positive Displacement Compressors for Refrigerator Freezer and Air Conditioning Application | |
| Domingorena et al. | Performance evaluation of a selected three-ton air-to-air heat pump in the heating mode | |
| Levins et al. | Modeled and measured effects of compressor downsizing in an existing air conditioner/heat pump in the cooling mode | |
| Lane et al. | Method and guidelines to establish System Efficiency Index during field measurements on air conditioning and heat pump systems | |
| Gardner | Thermodynamic analysis for industrial refrigeration systems | |
| McMullan et al. | The effect of oil on the performance of heat pumps and refrigerators—part one. Experimental test facility | |
| Vaisman et al. | Computer Aided Analysis Of Results Obtained From Calorimetric Testing Of Mobile Air Conditioning Systems |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |