WO2014112888A2 - A method of improving energy usage with positive net savings at end of life of existing installed air conditioning and refrigeration systems - Google Patents

Abstract

This is a collection of devices that is used to augment the existing components of an installed air conditioning or refrigeration system to reduce its energy usage. Large portion of the energy usage are increasingly getting expensive, installation of the upgrade on existing air condition and refrigeration units which are a major user of electric energy has immediate impact on the national economic problem since the installed base on these equipments are about 2.5 to 3.5 times the market for new equipment. It has the added benefit of providing positive net saving for the user for the remaining statistical life of the equipment. It would generate a large number of jobs in time with the prevailing economic situation. It is a simple process to install and can be provided as a kit that can be installed by HVAC technicians.

Description

FINAL PATENT APPLICATION

A METHOD OF IMPROVING ENERGY USAGE WITH POSITIVE NET SAVINGS AT END OF LIFE OF EXISTING INSTALLED AIR CONDITIONING AND REFRIGERATION SYSTEMS

CROSS REFERENCE TO RELATED APPLICATIONS

The following are references:

1. Final Patent application 201 10292172 TEMPERATURE CONDITIONING SYSTEM TO

OPTIMIZE VAPORIZATION APPLIED TO COOLING SYSTEM, Moises A. dela Cruz Filed USPTO Jan. 7, 2011

2. USPTO Provisional Patent Application 61681973 Aug. 10, 2012 System Structure for

Upgrade to Improve Energy Efficiency of Existing Air Conditioning Systems, Moises A. dela Cruz, Cottage Grove, Minn. USA

SEQUENCE LISTING OR PROGRAM

Not Applicable

ABSTRACT

This is a collection of devices that is used to augment the existing components of an installed air conditioning or refrigeration system to reduce its energy usage.

Large portion of the energy usage are increasingly getting expensive, installation of the upgrade on existing air condition and refrigeration units which are a major user of electric energy has immediate impact on the national economic problem since the installed base on these equipments are about 2.5 to 3.5 times the market for new equipment.

It has the added benefit of providing positive net saving for the user for the remaining statistical life of the equipment.

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It would generate a large number of jobs in time with the prevailing economic situation.

It is a simple process to install and can be provided as a kit that can be installed by HVAC technicians. BACKGROUND

Countries around the world deal with the task of providing adequate supply of energy for their ever increasing domestic energy consumption on two fronts - supply and demand. One approach is to find or develop new sources of both mined and renewable energy. Examples of mined sources of energy are fossil fuels like coal, oil and gas while solar, wind, hydro-electric, and geothermal sources are examples of what are renewable. The other approach is to improve the efficiency of both the "on-the-drawing-board" and the installed energy consuming

equipment.

In this application when we use the term efficiency it is to imply electric energy usage or fuel usage if non electric prime movers are used for the compressor.

This application is about installation of "kits" for the improvement of the efficiency of installed air conditioning and refrigeration systems and profit from the savings in energy during the remaining life of the equipment.

It behooves that since as stated we are dealing with efficiency that we define what the terms mean? I shall introduce two efficiency metrics in this document. The US Department of Energy (DOE) defines the metric of EER (energy efficiency ratio) which is the energy obtained in terms of BTU/hr to the power used to effect the cooling process. Associated with EER is COP which is the coefficient of performance and COP is EER/3.4. This metric is obtained under standard environmental conditions defined by the DOE under steady state (constant stable non changing operational conditions). The operation of the equipment is dependent on the environment such as ambient temperature, relative humidity, exposure to wind, shade location, weather (raining or not), etc. Thus it is akin to the usual efficiency metric we are familiar with in physics.

As a trivia a heat pump with a COP greater than one when operated as a heater is more economical than an electric heater for the same heating capacity. For example if the source of the heater energy is also electric, then with a COP of 3, a user would be paying one third of the cost of an equivalent electric heater. I introduced this trivia because it is not know to most people and therefore a significant benefit of a heat pump is overseen.

We shall use the term EER in a looser context to convey a metric of efficiency outside the defined conditions on the EERdoe as mandated by DOE (Department of Energy). We shall allow the use of EER to a metric of efficiency in a general way where the parameters particularly in our discussions are changing.

The term EERdoe means the EER as defined by DOE. Also we will use EER to convey a general efficiency term under varying parameters of operation of the system.

Air conditioning system as stated operate under very wide environmental parameters and the EER metric does not lend a complete semblance of the bottom line interest of users. The current metric of SEER which is an averaging method for EERdoe and is the performance of the equipment with ambient temperature as a variable modified on coming with themetric of EERdoe. It does not lend itself still to the bottom line information that users want. Users are interested in the net total energy usage for the duration of the life of the equipment or during monthly accounting, or yearly accounting. Since these variables cannot really be specified and even predicted, the bottom line needed cannot be obtained.

However, the equipment control strategy can be designed to assure optimizing the "EER" beyond the specific conditions required by DOE to cover the range of variations of of all parameters affecting the usage of energy of the equipments. This could be obtained by optimizing the "physics" definition of efficiency of the equipment under constant and stable conditions at the conditions of the operating state of the parameters affecting the ratio. It is to maximize the ratio of "what am I getting out?" to "how much am I spending". This is to be compared with EERdoe, exactly the same but with all parameters defined and specified values.

The air conditioning or refrigeration equipments are a system. It consist of a collection of different devices with particular functions for the delivery of the objective for the equipment. There are a lot of parameters involve in the design of the various devices consisting the system. Most of these parameters are frozen once the device is manufactured and installed. However, the device or the system ma have capability to modify some physical parameters affecting the system performance. Since the system, which in this particular case is an air conditioning or refrigeration system is affected by a lot of parameters during its operation, some means of adopting to modify the performance of the system is available to obtain the objective

performance more favorably. For example, the heat exchanger convective air flow velocity could be changed to effect a better convection process with the change in speed of the fan. The setting of the room temperature could be changed. The setting of the operation point for the refrigerant may be changed by changing the superheat (we will define this later) feedback setting. In this particular application, the upgrade would consist of adding another and/or device This is assured if the strategy is to maximize the efficiency by matching the continuous operation of the unit to match the cooling load. This is the optimization of the "EER" under all parameter variations by matching the refrigerant mass flow rate with the cooling load.

The economy of operating an air conditioning unit has not made energy efficiency an important metric until recently. The issue of rising fuel prices and environmental degradation has been more visible for the last 2-3 decades and efficiency has been of concern. The installed air conditioners have relatively unfavorable efficiency and therefore the government had mandated programs and controls to gradually improve the equipment efficiencies. Thus the metrics of EERdoe and SEER were defined. Nevertheless because of the wide number of dependent variables to the metric that is attempted to be conveyed by the DOE, they have to narrow them down and be specific on the parameter conditions where the metric is measured. The control of the components of the air conditioning system especially residential and small commercial units had been using the hysteretic method of control. It afforded a very simple and economical control.

The hysteretic control enables the activation of the air conditioning system when the controlled room temperature exceeds a threshold Trmhi which is higher than the Trmset setting required for room temperature control. The room temperature slowly reduces with the cooling and when the threshold level Trmlo is reached, which is lower than Trmset the unit is turned OFF.

The compressor in most cases are reciprocating piston. The operation consist of two distinct cycles. The first is the introduction of the refrigerant from the cooling heat exchanger

(evaporator) called the suction stage to the compressor chamber. Exactly 180 degrees from the compressor cycle of initial suction stage, work is applied to the refrigerant volume inside the compressor to compress the gas. The mass of the refrigerant for compression maybe approximated to be constant under the narrow range of refrigerant evaporator output temperature.

The type of air conditioning system VPRS (vapor phase recovery system) functions in the heat flow is enabled from one section (evaporator or room to be conditioned) to the environment as a sink. This is enabled by heat exchanger in the room called the evaporator and the condenser that releases the heat from the evaporator to the environment. It is a close loop system in that the refrigerant (fluid used for the heat transfer) is completely recycled. However, in the process work has to be spent by a compression stage, and a mechanism for changing the state from the condenser fluid suitable for the evaporator by the throttling valve are needed. The magnitude of the heat energy transported is proportional to the change in the phase of the refrigerant in changing from liquid to vapor in the evaporator. The condenser similarly has to remove this energy together with the added energy from the compression stage. Since the system is close loop, the same amount of refrigerant mass is circulated through the evaporator and condenser. The energy change on the process of phase change from liquid to vapor called the enthalpy change (per unit weight) is dependent the pressure and temperature. The amount of energy involved can therefore be modified by changing the saturated pressure (or saturated

temperature) and the refrigerant mass flow rate.

On a reciprocating piston compressor, the rotation or cycling speed of the compressor is constant and invariably the amount of refrigerant mass flow rate is also almost constant (the density of the refrigerant does not significantly change over the range of evaporator temperature range). When the rated cooling capacity of the unit is specified Qrated, the hysteretic control is used to provide an average cooling capacity of Qrated. Under this scenario, the hysteretic controller keeps system ON (usual design followed) continuously. When Qload is less than Qrated the equipment is cycled with a duty cycle such that on the average the equipment delivers the average cooling Qload. If all other conditions affecting the operation of the air operation of the system is achieved, the equipment will turn ON and OFF with a_Tjegular period Tss and duty cycle Dss. If the time duration it is ON is Ton then the duty cycle is equal to

Ton/Tss. However unfortunately the efficiency of the equipment over the duration of use is dependent is still on the average ERRdoe which is the lowest efficiency for the system considering the variations of the other operational parameters during the cooling activity since the system is providing the full power capacity during the time it is ON.

We may explain the previous statement of efficiency by invoking the Carnot theoretical efficiency for the VPRS system. We stated previously that the enthalpy change in the refrigerant is dependent on the saturated pressure (saturated temperature) and the mass flow rate. The Carnot theoretical efficiency is given by

Tsatlo/.(Tsathi-Tsatlo)

Where Tsatlo is the saturated temperature at the evaporator and Tsathi is the saturated temperature at the condenser. When the heat exchangers are designed (evaporator and condenser) the usual thermodynamic process involves conduction and convection. When environmental conditions to which the heat exchanger is operating is constant, the temperature change of the air flow through the heat exchangers is proportional to the heat load involved. Thus under Qrated the air flow temperature change ΔΤ rated which I called the "rated temperature head" which in the case of the evaporator is (Trm-Tsatlo) and with the condenser as (Tsathi-Tambient). For a heat exchanger heat load less than Qrated, the corresponding temperature head is proportionately less than "rated temperature head" which implies that the denominator of the Carnot efficiency equation is less than at Qrated heat load. The result is a higher theoretical Carnot efficiency cycle. We may extrapolate that the actual efficiency would similarly follow the trend indicated.

Under actual conditions also on a refrigrigerant, a reduction in Tsat approximately result in an increase in enthalpy and therefore for the same cooling load, the refrigerant flow may be reduced. This shows that a reduction in Tsat would imply a reduction in refrigerant mass flow rate. This is the control method as applied to VFD, scrool/inverter and the application of the modulation valve.

Assume now for argument that the other parameter that changes Qload is ambient

temperature. EER improves when Qload is lower than Qrated and ambient temperature is lower than the specified requirement for EERdoe. The ambient temperature changes during the day and through the season the EER (see Carnot equation). When the cooling load is lower than Qrated, the efficiency EER is higher than EERdoe. SEER metric accommodates this variation. It averages the EERdoe over the "bins" of temperature specified by DOE. It is indicative of the energy usage under some assumptions of cooling load and ambient temperature and its duration. In industrialized and developing countries, air conditioning and refrigeration account for a large portion of their total energy consumption. Programs and policies mandating efficiency improvements in air condition and refrigeration are stated in either the EERdoe or SEER metric.

We pointed out that the metric on the bottom line on efficiency is not addressed by EERdoe because of the narrow confinement required for obtaining the metric under real operating conditions for the system. DOE has also defined the SEER of the equipment to address the issue. It extends the dependence of the efficiency metric to variations of ambient temperature by requiring manufacturers to test the EER of the units under steady state conditions within temperature "bins" that is defined by dividing the range of temperature operation of the equipment into 12. By weighing the relative time in which the equipment operates within this bin and averaging the cumulative EER performance over the time considered, the test obtains the SEER rating of the equipment. Again one can see that the metric does not cover and come out with the bottom line performance of the equipment.

It is almost an impossible task to come out with such a bottom line metric. The use of hysteretic control of the equipment maintains an average efficiency performance of EERdoe. SEER still is obtained under full load conditions and therefore it only conveys the effect of ambient temperature. However, the method of matching the refrigerant mass flow rate to the cooling requirement Qload comes close to the metric desired. If one were to assume other parameters including all other control means affecting the performance of the air conditioner system were fixed then if the mass refrigerant flow rate control to match to the evaporator cooling load would provide the needed energy for the cooling load. It will control to eliminate the situation of more than needed refrigerant flow or deficiency in cooling due to inadequate refrigerant flow. Since all other devices and operational parameters are not changed, then the delivery of the correct amount of refrigerant would satisfy the minimization of energy used for the cooling load This procedure for controlling the equipment is dependent on EERdoe and is largely dependent to it.

The operational parameters such as ambient temperature, cooling load, wind, over cast days all affect the performance on energy usage of the system. Specific evolution of all these parameters are simply not available and repeatable to make judicious comparisons on performance. It could be at best an statistical metric. However in particular for the case of an upgrade, with no other parameters changed, refrigerant mass modulation effecting the support for an exact delivery of the cooling requirement for the system is a very reliable subjective measure for the client. The psychological information for them that they are getting all the time the best result of the energy expense without an actual metric number goes beyond the specifications of EERdoe and SEER.

The application also proposes a means by which a metric maybe obtained to prove indeed the contention of minimizing the energy usage. The application proposes a way of measuring the cooling energy delivered to the target area and also the measurement of the actual enerqy One can see that the improvement of EERdoe automatically improves the long term efficiency of the system with or without the introduction of the mass refrigerant modulation control.

It is known that various parameters affect the efficiency of the extraction of heat for cooling. However, the process of matching the refrigerant to the cooling load is the final target and that we have shown already that under all other things being constant, that refrigerant mass flow rate optimizes the performance for a given EERdoe system That is if the clients were aware that with the variations affecting the efficiency performance of the air conditioning system, the strategy of optimizing all the time the performance of the system with mass modulation assures them that they are getting the best return for their money.

The market for upgrade of installed air conditioners to improve efficiency is considerable. The United States alone, about 70 - 85 percent of the total potential market for air conditioners have installed units and most of these units employ a reciprocating positive displacement

compressor. The service life, in years, of an air conditioning system is obviously dependent how long it operates in an average day and such usage is indicated by the "degrees cooling-day" metric. For the continental US the "degrees cooling-days" range from 350 to 3500 and the corresponding service life of the equipment range from 10 to 25 years. The service life of an equipment may also be stated in expected service hours, a measure on how long it is capable of operating continuously until it fails.

For the consumer, the justification for an equipment upgrade will depend on the payback period brought about by the energy savings realized for the remaining service life of the upgraded unit. The stream of money saved from upgrade depends primarily on the cooling capacity of the equipment and the local cost of a kilowatt-hour of electrical energy.

The favorable places for upgrades are where air conditioning is almost a necessity, the cost of electrical energy is high, and it is difficult to raise capital for new equipment.

ECONOMIC IMPACT AND MARKETING STRATEGY

Compared to procuring new more efficient systems, the upgrade of installed HVACs has the advantage of requiring less capital for its development and marketing. The upgrade scenario would conveniently merge with the existing organizational structures for sales, distribution and system maintenance of current HVAC products. Offering the product as a "kit" is a natural fit to existing marketing organizations that have always featured upgrade components for maintenance, repair, and replacement to HVACs installers.

Considering the large number of variations of manufacture and models, it is the responsibility of the kit manufacturer to recommend the proper upgrade "kit". The HVAC distributors and installation personnel which are probably mom and pop operations are relieved of the task and responsibility even if they are qualified to do it.

Marketing strategy of optionally providing information on actual cooling delivered may be part of the embedded controller design. This would include the capability of monitoring the liquid refrigerant flow delivery at the entrance of the throttling valve. It is implicit that the refrigerant is almost in the liquid phase. This marketing strategy would be established as the first units are installed. The purpose is to gather data for its performance and provide clients proof of viability and performance of the upgrade. The capability of wirelessly transmitting data to a collection server either in batch or real time is very possible.

If the cost of implementing such performance data gathering is economical, the option is there to make it a permanent feature of the upgrade.

Current trade publications indicate that although installed HVACs with scroll/inverter

compressors have implications of improved EER, the payback period that can be realized from the unit is unfavorable especially in places with very favorable energy price. This is not the case on the upgrade of an installed unit with a reciprocating positive displacement compressor and of equal cooling capacity. The upgrade provides a path where money saved from operating the upgraded system is accrued for the remaining life of the unit and can then be applied for the acquisition of the more expensive brand new state of the art high efficiency air conditioning or refrigeration unit. Note also that scroll/inverter compressors have not established their reliability and durability at this time.

A widespread upgrade of installed air conditioning and refrigeration units will be a shot-in-the arm for governmental programs for the attainment of its energy policy goals. Countries do not have to wait for the slow penetration of new equipments with higher efficiency design to make big strides in achieving most of its energy savings goals. Also, the financial benefits from the aggregate savings in energy will improve a country's economic health on the whole.

It is advantageous also that the immediate implementation achieves more bang for the money. Also the other reason is that it is of importance touse the slogan "strike while the iron is hot" because when the installed base is of lower energy efficiency metric then the percentage effect of an improvement is larger. (Note, the percentage improvement ratio is inverse to the existing efficiency).

LIST OF FIGURES

Figure (1) Representative block diagram of VPRS system

Figure (2) Block diagram of first upgrade embodiment (valve on compressor output)

Figure (3) Block diagram of 2^nd upgrade embodiment (valve on suction input compressor) Figure (4) Block diagram with water vaporization implemented on condenser

Figure (5) Exploded view of modulation valve

Figure (6) Isolated detailed view of bypass channel on modulation valve

Figure (7) Timing diagram functionality for control

Figure (8) Modulation valve structure showing sensor for speed of rotation control

Figure (9) Timing diagram for synchronization of rotor speed to compressor cycles

Figure (10) Sketch of modulation valve for multiple piston compressors

Figure (11) Sketch of modulation valve applied to the suction line

Figure (12) Exploded 3D view of the modulation valve ·

A LITTLE THERMODYNAMICS FOR VPRS AIR CONDITIONER AND REFRIGERATION

SYSTEMS

The following is a short discussion on the VPRS (vapor phase recovery system) air

conditioners. A short explanation was taken above. It was explained that the VPRS system is a closed loop system where phase change is enabled for the directional flow of heat at the evaporator for the extraction of the room heat, and at the condenser to remove the heat from the room and the added work of the compressor to the outdoor sink.

Figure (1) is a typical block diagram for a conventional VPRS system. Figure (2) shows the addition of the upgrade. Another implementation of the modulation valve upgrade is shown in Figure (3). The function of the modulation valve shall be discussed in the later section of the application.

A typical VPRS system consist of five major components. Four of the components are primarily involved with the thermodynamic process. The major components are the condenser 156, the evaporator 106, the compressor 108, the throttling device 104. The throttling device is implemented either as a restriction device like a capillary tube in low capacity cooling units or a thermal expansion valve using one of the temperature sensors 152 to detect superheat temperature as feedback to control an orifice opening to regulate evaporator heat exchange properties. The block diagram uses only the identification 152 for each of the temperature sensors because an embodiment not discussed here provides a two wire temperature sensing for multiple points. The last component is the controller 158 for maintaining the operation of the compressor and other sensor devices as pressure sensor 156 and temperature sensor 152. The information from the sensors is used by the controller to turn ON or turn OFF the compressor motor and fans. The evaporator 106 extracts the heat from the room since the evaporator refrigerant is at a lower temperature than the room. The condenser 156 dumps out the heat acquired by the refrigerant from the room together with the added energy to the refrigerant from the compressor to the ambient air. The compressor 08 performs work on the refrigerant to change the refrigerant pressure and temperature Psathi, Tsuphthi to enable the condenser to release the energy on it. The initial cooling done by the condenser is to bring the superheat temperature Tsuphthi to the saturated temperature Tsathi corresponding to the condenser pressure Psathi. The throttling valve 104 performs a similar function as the compressor but changes the phase characteristic of the refrigerant to Psat!o, Tsatlo to enable the evaporator 106 to extract the heat from the air flow from the room. The refrigerant temperature Tsatlo is lower than the room temperature. The refrigerant at the output of the compressor is mostly totally, superheated vapor and is cooled in the condenser with the heat flow from the refrigerant vapor to the ambient environment. This changes the refrigerant from a vapor to a liquid when the heat is released from it to the environment. The term saturated refrigerant means the region on the refrigerant material phase diagram where the refrigerant exist in both liquid and vapor. If it is totally vapor, it is superheated. If it is totally liquid, it is sub cooled. The refrigerant exhibits a constant pressure Psat and temperature Tsat between the region between of liquid and vapor saturated state. This is not generally true for newer refrigerants. Some refrigerants exhibits the "glide" in temperature. This is particularly true with refrigerants consisting of mixtures or blends of different refrigerants that exhibits different saturation temperature. The "glide" is related to the different values of Tsat for each of the different refrigerants causing noticeable differences in the liquid Tsat and the vapor Tsat.

The purpose of the application is for the improvement of VPRS efficiency and therefore we are going to present again the theoretical basis of the efficiency performance of the system which is the COP (coefficient of performance) which has the upper theoretical limit of

Tsatlo/(Tsathi-Tsatlo).

Superheating means that the refrigerant absorbs more energy under the given pressure to change the refrigerant state completely from liquid to vapor (saturated region). This assures that the refrigerant from the evaporator 106 would be completely vapor. It is a common strategy especially for reciprocating piston compressors to avoid the existence of liquid refrigerant to the compressor that leads to damage in the compressor valves. Superheat temperature sensor is usually used as a feedback control parameter. It is used for the feedback mechanism of the diaphragm thermal expansion valve. The method of acquiring the superheat temperature with a bulb intimately attached to the evaporator exit exhibits a deficiency that TEVs have large thermal constant and causes problems on control. The usual control problem they present is what is called "hunting" which is an instability problem.

On the other%hand, at the output of the condenser the refrigerant may be cooled beyond the recommended process by the DOE to improve the efficiency of the system. Sub cooling extends the enthalpy change of the refrigerant for the evaporator operation resulting in lesser amount of refrigerant mass flow for the given cooling load.

Auxiliary devices like receivers and accumulators serves as temporary reservoir for the refrigerant as it undergoes phase changes for the close loop air conditioning system.

VFD AND SCROLL/INVERTER TECHNOLOGY FOR UPGRADE VS PROPOSAL

The application is a procedure for which an established and accepted improvement in efficiency of VPRS system is implemented through a process of refrigerant mass flow adjustment to match the cooling load of the system.

The implementation of the process has been implemented and used for several decades. The system uses the term VFD which means variable frequency drive. With the compressor cycle being adjusted, the refrigerant mass flow rate is correspondingly reduced. The motor for these systems are AC motors and the variable adjustment of the drive frequency results in

compressor speed adjustment. The efficiency improvements in these applications had been documented to be as high as 35 percent improvement. These systems are primarily in large industrial and commercial systems however. The use of VFD could be extended to the air conditioning drives of compressors and fans. However under an upgrade scenario, this involves quite a large change to the system. If we were therefore to follow the philosophy dictated in an upgrade the VFD as an upgrade is not economically feasible for the usual residential and small commercial units. The reasons are that it would involve changing the drive that would be suitable for VFD drive. Since most of the motors used are induction motors, the designed magnetic have narrow range of frequency of operation. The use of the inverter that changes the alternating current source to direct current voltage allows using a DC motor for the compressor drive. * These motors lend very easily to variable speed control.

There are problems that are magnified by the nature of the implementation of VFD and inverter drives. Both procedures convert also the utility alternating current to DC (direct current) and in the case of the VFD converts the DC voltage into alternating current for the alternating current motors. The same process is used with the scroll/inverter combination but usually the motor drive are DC since the electronic is simpler. The technique however generates problem of creating harmonic rich frequencies. Third harmonic currents are generated that end up flowing in the neutral of the utility line. Large computer systems and cities in general with a lot of computer systems are getting attention from the utilities because of the third harmonic. The effect is to route third harmonic currents generated to the neutral line of the utility system. The formerly almost insignificant component of the neutral current on the utility system distribution now is becoming a problem, This is aggravated by the VFD drive and inverter implementations. If the positive displacement motors used in installed systems are retained and operated as before the creation of third harmonics are avoided. The last decade marked the introduction into the commercial and low capacity markets of the using new scroll/inverter technology. The commercial viability was enabled primarily with the reduction in price of power supplies for driving the DC motors needed for the inverter. This was driven by the advances in switch mode power supplies and subsequent application to high power requirements such as the hybrid car.

As explained previously, if the air conditioning system is operated continuously where the refrigerant mass flow rate is adjusted continuously to match the requirement of the cooling load, the system efficiency EER improves from the existing hysteretic controller for the older systems. Some of the benefits documented in VFD drives involve the energy on the fan motors and dampers that could save for example on the fans a cubic relationship to speed. Since the fans are a smaller fraction of the net usage of energy for air conditioners, the focus therefore is on the compressor motor.

The SCROLL/INVERTER units appear in different flavors. Some of the modulation procedure involve for example a duty cycle application for compression together with motor speed control. There might be systems where the drive is at constant speed but the SCROLL compressor used on a duty cycle basis and achieve the modulation. Nevertheless, the point is that in all probability the efficiency achieve under that situation yields a lower efficiency than the modulation valve because if the compressor starts working at a duty cycle, it means that the motor speed drive is higher than what it should be and would have lower overall efficiency.

The electronics are needed for the variable frequency drive but because of the fast edges of turning ON and OFF power switches, the attendant current generates a larger magnitude of EMC (electromagnetic compatibility noise) and requires a complicated technology to make it conform to the radiation and susceptibility requirements for equipments generating these sources of undesirable signals. The EMC is however probably a smaller problem because the edges for the signals are not as fast as the digital circuits. The main problem on the inverter generation for drive signals is the creation of third harmonics of the utility line that increases the amount of current in the neutral line. Initially, utilities have not accounted for the larger third harmonic in modern equipments. This leads to overcapacity on the neutral lines on services from utilities leading to large losses and attendant heating problems that increases

geometrically problems.

The upgrade on using the modulation valve does not change the way the induction motor is driven. Therefore the 3^rd harmonic problem that would have been created by the inverter is alleviated. Again with the continuous use of the unchanged utility waveform, these EMC problems are minimized with the upgrade path being proposed.

OBJECTIVE OF PATENT APPLICATION The patent application defines a scenario by which upgrades to the existing air conditioning equipment maybe implemented. In particular, the application is for the upgrade of existing air conditioning and refrigeration systems using positive displacement compressors. A device when introduced as an addition to the existing system allows the existing system to operate with similar performance achieved with the popular scroll/inverter air conditioner systems, at a fraction of the cost. The payback period achieved allows one to replace the older upgraded unit with a newer high efficiency system at the end of life of the unit with the savings accrued with adapting the upgrade. The upgrade consists of processes familiar to HVAC personnel and these are: recovery, evacuation, installation of the "upgrade kit", and introduction of the refrigerant and system calibration and configuration for the embedded controller. The devices, procedures and control techniques developed are not limited to the upgrade scenario for implementation.

Figure (2) is the block diagram as an embodiment of the upgrade for a VPRS system when using the modulation valve. All the components are retained which were previously identified as the basic component blocks in Figure (1). The added components are the modulation valve 114, electronics for control of the modulation valve 8, a bypass reservoir 116 to prevent liquid refrigerant from entering the compressor suction line, and possibly a heater 120 to prevent refrigerant condensation" in 115.

Figure (3) is another upgrade implementation where the modulation valve is located at the suction side of the compressor. The valve designed for Figure (2) can be used but plumbing circuitry is needed to be changed. The modulation valve discussed is applicable where now the different port functions are changed. The condenser port input now becomes the suction line port to the suction side of the compressor. The high side compressor output becomes the connection to the reservoir output. The bypass channel port is closed. The functionality is the modulation valve is now a flow switch and the reservoir retains portion of the reduced what was normally the full refrigerant mass being compressed by the compressor. It is not understood how much energy is lost because of the work done in reducing the pressure at the compressor chamber and whether that same work is recovered during the compression stage. It is intuitive that it is a balance recovery but testing has to be done.

Most of the discussion in this application is modulation on the high side output of the

compressor.

The modulation valve serves as a bypass of the refrigerant from completing the close loop cycle through the condenser and the evaporator. Another common implementation is the so called "hot bypass". The process routes the compressed refrigerant from the compressor back to the suction line or some other section of the system. It achieves the same purpose of refrigerant mass flow rate regulation but suffers from low efficiency because the refrigerant vapor has undergone compression and therefore use of energy that is not made to perform a useful function. The implementation of the modulation valve in this application avoids the problem 1

no work has been performed by the compressor. That results in the compressor doing work only on the refrigerant mass that is needed by the VPRS system.

Figure (4) shows another upgrade employing modification or change on the condenser. In this case, water vaporization is implemented to achieve a Tsathi that is almost equal to the ambient temperature Tamb. The process involves application of a patent application USPTOxxxx.

Details will be covered in a future application.

COMPARISON WITH PROPOSED MODULATION VALVE WITH VFD AND SCROLL/INVERTER FOR REFRIGERANT MASS FLOW RATE CONTROL

The use of the proposed modulation valve has the benefit accrued from the minimization of the generation of the third harmonic. The upgrade using VFD would violate the stated principle on upgrade because it would then means changing the installed drive and controller for the system. The modulation valve is a transparent addition to the existing control and devices in the existing equipment. The hysteretic controller is operated continuously and the embedded controller capability to keep the system ON all the time and avoid the hysteretic control implementation. There are easy technique that would enable this without modifying the controller and the hardware involved on the control such as having the embedded controller provide the enabler for the compressor operation. The literature on the documented improvement in energy usage of VFD drives included the effect on the variable speed control of the fans. The impact is quite high because the energy for fans is cubic in relation to the fan speed. Therefore the

documented savings of energy is also a major contributor to the improvement. Unfortunately our upgrade philosophy would make this strategy not practical. It does not however preclude using it on new equipment designs.

The upgrade enables the operation of existing air conditioning system using the reciprocating piston compressor but provides the functionality of the SCROLL/INVERTER system. The latter is new technology with the SCROLL compressor and is more complicated mechanically than the positive displacement compressor. At this time, the SCROLL/INVERTER compressor technology has not sufficiently matured to have a significant manufacturing advantage and have proven reliability. The positive displacement compressor on the other hand has been around for decades and has established reliability and proven manufacturing technology. The use of the modulation valve is more economical in that it does not need complicated semiconductor circuitry like the kind used for the INVERTER motor drive of the scroll compressor and its attendance mechanical complexity. In contrast the modulation valve is a simple mechanism that can be easily machined. It does not have any seals to deteriorate and the enclosure is like a seamless plumbing connector since the external drive to the rotor is driven by magnetic force which would penetrate transparently through non magnetic materials. The neodynium magnet is a convenient high strength magnet. It is only one possible embodiment to achieve the drive isolation. For example the magnetic force external to the rotor may use an electromagnet. lathe and milling machine yielded leakages of less than 3% and is a tolerable performance when the control is a feedback configuration. The electronics would also involve the ubiquitous computer chips and semiconductors. The reliability of the existing system has already been established and the simplicity of the modulation valve would sustain that level of reliability.

It is anticipated that diaphragm type of thermal expansion valve or the capillary tube which are the usual throttling devices might not be suitable to operate within the main change which is the sa_tni and T_sathi. The existing range of model capacity for TEV available in the market might not function within the range when upgrade is implemented. In such eventuality the modulation valve can be modified easily to include a servo control and channels that enable the refrigerant mass to be throttled by constriction that is created and modified with a rotor's angular position. A patent application is to be submitted.

The behavior of the thermal expansion valve not matching the system dynamics have been documented in articles about observed hunting. It was also observed with my initial

experiments with condenser cooling with water vaporization. The digitally driven thermal expansion valve that is fabricated using the same technique as the modulation valve will provide a much faster response commensurate to the effect of the other changes in the upgrade. It also makes the adjustment on the cooling capacity wider and easier to mechanize.

(1 ) MODULATION VALVE EMBODIMENT

The modulation valve serves as the means by which the refrigerant mass flow rate

characteristics of the VFD and scroll/inverter systems can be applied as an upgrade to existing air conditioning system. Most of these installed systems uses reciprocating piston compressors that operate on hysteretic mode of control. Natural constraints prevent the reciprocating piston compressors to perform and achieve the needed result on the VFD and scroll/inverter systems.

The modulation valve enables this function as an upgrade. It is added on to the existing system by inserting it on the refrigerant circuit at the compressor output and compressor suction ports.

There are two basic problems for the modulation valve. The compressor is operating at constant speed and there is no coordination or synchronization means available for the modulation valve to effectively function with it. The modulation valve overcomes this problem by operating the rotor or the gates of the modulation valve synchronously with the compressor. That is, if the compressor which is usually driven at 60Hz with a usual cycle speed of 3600 rpm requires the rotor to also spin at 3600 rpm. This is done with an electronic comparator circuit to compare it with the 60Hz from the utility.

The modulation valve one synchronized now would have to lock into the phase cycle of the compressor. This is enabled by jogging or disturbing the driving force for the DC motor to either accelerate it or slow it down but still recover to the constant speed of 3600 rpm. All of these are done electronically with the aid of position sensors on the rotor of the modulation valve 800, 892 and 804.

This application is applicable to positive displacement compressors. The idea of tailoring the refrigerant mass flow rate to the cooling load is shown with VFD to be effective. During the actual operation of the equipment other parameters are changing and the modulation of the refrigerant automatically adjusts the performance towards an optimum efficiency. The modulation makes use of the "gating" characteristic of the valve. As a result of that action, it shuts off or closes the port it gates. So at the suction side as the piston starts from top dead center position to move down, it lowers the pressure of the space on top of the piston and causes the valve to open the port to the sump. As the piston continues to move further down for the rest of the downward stroke, it draws in a charge of refrigerant vapor into the cylinder. For an unmodified compressor, at the discharge side, the valve for the discharge port remains closed and it only starts to open when the pressure inside the cylinder and the pressure at the space on the other side of the valve are at approximately equal. From the beginning to the end of the compression stroke, the valve at the suction port remains closed as long as the pressure inside the cylinder is higher than the suction side. Now break the plumbing between the discharge port and condenser and insert a bypass modulation valve.

The application is intended as an upgrade. The idea however is not limited to the logistic of how it is implemented which in this instance is outside of the compressor because of the target of the device for implementation. Actual implementation could of course be integrated with the compressor mechanism for new design.

The modulation valve consist of the following sections. It consist of a mechanism 544 to drive the shaft and disc 544 containing the neodymium driving magnets 504. The disc and shaft assembly 540 is cradled bottom of the cap 550. The bottom of the cap 550 is designed to be thin so that the magnetic force from the opposite pairs of neodymium magnets 504 are not compromised in generating the needed torque to rotate the rotor 502 with the constraint that it should be robust to bending and other outward pressure forces from inside the enclosure 506. The cap 550 is installed to the enclosure 506 to achieve a hermetically sealed structure with the use of complementary NPT threads 510 on the cap and the enclosure. Another magnet xxx is mounted distinctly separate from the driving magnets that would serve as a reference point to mark a position in the disc 544 that serves as a signal to determine the speed of rotation of the rotor.

The rotor is shown in Figure (5) as 500. The rotor is made of one piece of non magnetic material. Neodynium magnet are mounted on the top of the rotor with mounting holes arranged exactly opposite a driving disc 540. On the rotor surfaces there is refrigerant between the spaces, viscous friction occurs as a driving load to the DC motor. The viscosity of the refrigerant has however a beneficial effect in that it serves as the seal that prevent leaks from one channel in the rotor to another to achieve the performance needed.

The rotor have channels gouged on the surface with adequate depth so that flow resistance does not impede refrigerant flow.

The enclosure and rotors and other members except for the magnets and the DC motor drive are non magnetic. Other embodiments would not require all those listed to be non magnetic. The important issue is to prevent magnetic flux from smearing to other sections of the structure that could weaken the forces needed for rotation drive and compromise the accuracy of rotor position. The modulation valve in acting as a valve would encounter the same problems of refrigerant leaks if there were a shaft or some direct drive to the rotor from the outside. The attendant packing needed for seals and the large amount of torque needed for such a rotation to synchronize the rotor speed with the compressor motor would be prohibitive. The modulation valve makes use of the indirect drive to the rotor by having a cap screwed into the enclosure with NPT threads that effectively seals any leaks through the threads of the cap. The cap is formed as a thin disk with periphery containing the NPT threading. The threads of NPT are characterized with a slight increase in the dimensions of the interface as the thread progress in the connection. This enables a very tight seal and provides a high resistance to fluid flow. The cap forms a cylindrical space on which a disk with mounted neodynium magnets is inserted.

Extending the idea of NPT threads characteristic of sealing, the'different ports involved with the modulation valve are shown. The three ports are designated as 530. Each is part of the hydraulic circuit that consist of the output of the compressor, the bypass to the suction side of the compressor, and the port leading to the condenser.

The port connections to the existing plumbing of the equipment under upgrade also maintain the capability to withstand the high pressure of the refrigerant. There are corresponding channels on the rotor aligned with the opening of the ports 530 in which the valve action is implemented with the rotation of the rotor 500. A possible embodiment is to use connecting tubes with NPT threads. These devices are very readily available from HVAC sources. Another would be to butt weld the ports to the enclosure.

The modulation valve consist of a rotor 500 that rotates synchronously with the compressor cycles. The electronic circuit to implement consist of a sensor on therotor speed of rotation in the form of for example a Hall effect transistor. Another would be a capacitive detector. The electronics simplified block diagram is shown in Figure (9). It consist of a comparator that compares a reference corresponding to the rotation speed of the compressor and the sensing signal for the rotor position. The schematic shows an analog circuit implementation but in actual implementation the controller (comparator and drive signal generation) could be part of the embedded controller that would probably come with the kit. The signal from the position sensor of the rotor generates a constant duration rectangular wave and therefore after filtering generates an equivalent signal to the speed of the rotor. There are channels in the rotor that are aligned with ports as the rotor rotates corresponding to the plumbing from the compressor, to the condenser, the bypass pass and the refrigerant suction channel. Thus during the rotation, plumbing circuit connections are established between the different input and output ports by the presence of channels suitably gouged on the rotor. The tolerance between the enclosure to the rotor is designed so that leakages from the ports through the flow resistance offered by the creation of the thin film of the separation (enclosure to rotor), with effective length corresponding to the channel separations, would have maximum resistance to leakage flow. Absolute achievement of zero leakage is not needed because of the feedback nature of the

implementation of the feedback control.

Figure (5) shows several sectional lines ΦΑ corresponding to the bypass channels, ΦΒ corresponding to the compressor high side output, <DC corresponding to the input to the condenser. These cross sections are shown in figure (6). Figure (6) is shown for a rotor that spins synchronously at half the speed of the compressor. The 3D exploded CAD drawing

Figure (12) is a rotor that spins synchronously at the same speed as the compressor.

The cross 516 and 520 are both coincident with the rotation of the rotor. This means that when the rotor is at this relative position with the compressor cycle part of the refrigerant is bypassed to the suction port. When the rotor is beyond the bypass region Obyp the output on the high side of the compressor 520 is temporarily blocked and with further rotation opens up the channel 514 delivering the output of the compressor to the condenser inlet 522.

The sectional views Figure (6) is shown at the start of the designed maximum bypass possible for the valve. The regular operating cycle for the compressor with no bypass occurs after

Obyp. The actual position as synchronized with the rotation of the compressor varies the position of the rotor with respect to the actual start of the compressor compression. The relative position of the time of the rotor with respect to the mechanical start of compression of the compressor is a metric on the amount of refrigerant bypassed by the modulation valve. The relative position of the rotor is electronically controlled with a feedback mechanism where the feedback sensor would be the superheat temperature from the evaporator. This serves as a feedback for the operation of the channels and ports for diverting the flow of refrigerant as the rotor turns in the clockwise direction.

The cavities are designated as 516 for the refrigerant bypass to the suction line, the cavity 520 which comes from the high side output of the compressor, and the cavity 522 which is connected to the entrance of the condenser are shown in their relative position. This position determines the switching or the refrigerant circuit from the compressor high side to either route the refrigerant to the suction bypass or the input to the condenser.

The previous discussion considers the case when the maximum bypass to the accumulator is maintained. The system will operate as before at full capacity when there is no bypass. This is true if the rotor has a phase relationship such that the rotor bypass channel trailing edge is aligned with the trailing edge of the bypass port. Thus one can see that the compressor channel section angle is larger than 90 degrees to accommodate the initial starting position of the bypass channel at the start of the compression cycle of the compressor. The suction line channel 516 is correspondingly adjusted for its angle of range. The separation between the condenser channel and the suction channel is chosen to be wide to improve the leakage resistance from the two channels.

The relative timing of the different ports, and the diversion action of the channels are shown in Figure (7).

Figure (7), Figure (8) and Figure (9) show the speed and synchronization of the cycles of the compressor and the modulation valve rotor. Figure (8) show the mounting of the Hall Effect transistor. It is located immediately above the magnet 804 situated as reference point on the phase of the rotor rotation. It consist of the mounting bracket 802 to detect the position of the magnet. The sensor signal would provide the information for measuring the speed of rotation of the rotor. The signal from the Hall Effect transistor figure (91) is not particularly sharp and therefore needs to be signal conditioned to sharpen the edges and also produce a constant width signal. The constant width then generates a signal whose filtered DC level will be proportional to the speed of rotation. This would provide the signal for comparison with the speed sensor from the compressor to maintain the speed of the rotor in synchronization with the compressor speed. This is shown in Figure (9d).

The feedback control on the regulation of the mass flow by the valve consist of adjusting the relative phase of channel 156 with the compression cycle. The measure for the feedback is obtained by the extent of the superheat temperature from the evaporator. This reflects the amount of heat extracted by the evaporator beyond the saturation region. Temperature sensor 156 and 150 measure the subcooled temperature at the condenser output and the superheat temperature from the evaporator. Temperature sensor 152 measures the corresponding saturated temperature of the condenser and evaporator. The physical location for mounting 152 are carefully selected during the upgrade process.

The partial schematic of the controller shown is analog in Figure (9). However to avail of the flexibility and low cost for more complicated control USPTP Provisional Patent Application 61681973 considers embedded controller as an option that creates a very flexible

implementation of the needed control algorithm.

The timing diagram is shown with coincidental axis of rotation angle and rotation time with reference to the start of compressor compression. It is shown with the case for the rotor rotating at half the speed of the compressor thus 80 degree rotation of the rotor is a complete cycle of suction and compression on the compressor. The subsequent timing diagram shows the region of the rotor position timing where bypass operation to the suction line could be achieved. The process of modulation may cause throttling if the remaining volume of the reservoir is larger than what is bypassed. This throttling effect'may cool the gaseous refrigerant and transform it into liquid. This would be disastrous to the reciprocating piston valves and could lead to failure. A heater 120 is fabricated and coordinated with the controller to warm up the reservoir bottom section to avoid condensation of the refrigerant. The heating process maybe performed in more economical way. For example the, use of the Peltier type cooling heating modules might be used because of convenience and simplicity in implementation.

The check valve action is maintained by the tight tolerance between and minimal separation between the rotor and the enclosure with compromise on the amount of energy needed to maintain the speed of the rotor. The sealing action is through the oil content of the refrigerant and the small space and tight tolerance in the fabrication process.

Figure (10) and Figure (11) shows the extension of the concept of Figure (5), Figure (6) to implement refrigerant mass modulation for multiple piston reciprocating compressors. In this particular illustration, it is for a 2 cylinder compressor. It consist of replicating the ports and channels in the single piston modulation valve on the output of the high compression side of the compressor and the suction side. The channels are shifted in this case by 45 degrees because our rotor was previously designed for a half speed rotation of the rotor. The plumbing has to be modified such that the suction line is common to both cylinders. Figure (10a) is the basic unit. To accommodate added pistons, the basic layer is duplicated but shifted by 90/n where n is the number of pistons. The suction layer is shown in figure (10b).

Note that the multiple piston configuration discussed above is also application to the

implementation with the valve on the suction side of the compressor as shown in Figure (3).

More cylinders would be enabled by duplicating the routing channels on the rotor and enclosure except they would be offset successively corresponding to the number of cylinders.

Figure (12) shows the exploded view of the modulator valve in 3D CAD drawing.

SECOND EMBODIMENT

The second embodiment block diagram for the upgrade installation is shown in Figure (3).

The mass flow rate of the refrigerant is controlled on the first embodiment from the compression side of the compressor. Similar effect maybe obtained if the mass flow is controlled on the suction ccle. The relative position of the rotor for the suction port may regulate the magnitude of the ingested gaseous refrigerant. In this embodiment the rotation of the rotor is reversed and the reference starting compression cycle is perform from the further limit of the input operation to the condenser in the initial implementation. In this case the modulation valve output to the condenser port becomes the suction line from the reservoir. The modulation valve input coming from the compressor output becomes the input to the compressor suction line. The bypass port [Type text]

Is sealed. This operation can be seen in Figure (5) and Figure (6). It is a simpler embodiment for the upgrade! However closing the flow of refrigerant to the compressor chamber during the suction operation might cool the chamber and lead to liquid formation inside which could be disastrous. The correction would mean raising the superheat temperature which would be dynamic unless a much higher superheat setting is used. It is not very clear what are the ramifications on this strategy but is a test that will be performed.

THIRD EMBODIMENT

Figure (1) shows the conventional VPRS system. Another embodiment may be applied to a new equipment that is not an upgrade. The embodiment uses all the changes discussed above but the condenser is implemented using the vaporization cooling procedure discussed in the reference on submitted USPTO application. The procedure would result in a much lower condenser temperature and subcooling close to the ambient temperature. Also under this condition the modulation valve discussed here could be implemented to be a modification that is internal to the compressor.

FOURTH EMBODIMENT

Figure (10) shows an embodiment where the modulation valve is modified to operate in a multi piston compressor.The modification involves replicating the basic ports for the modulation valve and stacking them in the rotor with an corresponding offset to synchronize the rotor operation with the integrated cycles from the compressor.

Claims

Claim (1) This is a means where the aggregate energy usage of air conditioning and

refrigeration system is reduced on positive displacement compressor with a compression cycle that build pressure through the compression cycle and operating either fixed rotational speed or variable speed. This is applicable to both upgrades and new systems. The means is an implementation of modulating the rate mass flow to corresponding to the required cooling load.

Claim (1a) Valve is used where suitable timing and synchronization of the valve rotor and the compressor cycle allows the modulation of the effective refrigerant mass flow rate for the heat exchangers.

Claim (1b) Valve arrangement where the bypass operation is synchronized to be at the start of the compression cycle and thus would require usage of minimal amount of compression energy.

Claim (1c) Valve consist of ports that route the refrigerant from the compress to the bypass port. The rotor has channels that allow flow of the refrigerant to the

corresponding port during the compression and suction cycles.

Claim (1d) Valve have channels such that both the flow of refrigerant is controlled under feedback. The rotor channel and the enclosure are fabricated such that sealing separating the gases involved during compression and suction are achieved with tight tolerance contruction of the rotor to the enclosure.

Claim (1e) valve may be applied where the mass flow of the refrigerant is through the modulation of the suction gas refrigerant.

Claim (1f) Valve maybe designed to achieve the degree of bypassing and final compressor pressure by suitable location of the boundary of the channels. The capacity of the channel has to be designed also such that especially in the suction stage, the fluid flow resistance on the channel is smaller than presented by the input pipe from the evaporator.

Claim (1g) Valve synchronization is obtained by having a position marker at the start of the cycle for compression in the form of a magnet located on the rotor and sensed passage by the hall effect transistor or module.

Claim (1h) Feedback speed control for the valve would consist of a fixed voltage setpoint for fixed rotation of the compressor or obtained from the utility power serving the equipment. The power waveform may be detected and similar circuit generating constant voltage and duty cycle would measure the corresponding compressor speed. The feedback would be obtained from the transistor hall effect, signal conditioned to generate constant current to a resistance network.

Claim (1i) Feedback control circuitry could be implemented with the embedded controller.

Claim (1j) Sensing mechanism allows the capability to manually position the rotor under failure mode to effect the seal of both the compressor and the suction gases.

Claim (1k) The bypassed refrigerant is contained in a reservoir. The range of variation in the reservoir pressure will depend with the size of the reservoir. There could be liquid formation and a Peltier type of heater would maintain the temperature needed to prevent liquid formation in the reservoir that might be ingested into the compressor.

Claim (2) A means to drive the rotor of the valve to avoid leakages and also the usual friction because of packing.

Claim (2a) Mounting materials and separation materials between the driven and the driving magnets are non magnetic Claim (2b) Magnets used are small button type neodymium magnets to avail of the large ; magnetic force per volume of the material. The means is not confined to these materials depending on the application considered.

Claim (3) A means to enable the sensing of the rotor speed, means to synchronize the rotor speed with the compressor rotation, an adjustment of the mass rate modulation with phase difference from the compressor.

Claim (3a) A sensor in the form of a magnet located close to the center of the rotor is sensed during its passage through a hall effect transistor.

Claim (3b) A feedback circuit that compares the speed of the rotor from the Hall Effect transistor and the compressor speed generates the voltage for the DC motor drive to maintain synchronization

Claim (3c) Temperature sensors to detect the magnitude of superheat temperature as feedback parameter. The error provides correction signal for the DC motor drive to adjust and job the motor to provide the correct rotor and compressor phase for proper mass flow modulation. _s

Claim (3d) The feedback control is implemented for the simplest configuration as analog circuit. A more capable embedded controller allows further improvement.

Claim (4) The process is applicable to upgrade for existing air conditioners and refrigeration systems. The process is applicable for new system that would still use positive displacement comressors. It would have the added advantage of having control to optimize the sizes of the motor and the heat exchangers.

Claim (4a) The process is applicable to new systems using usual VPRS configuration.

Claim (4b) The process is applicable to new system with the incorporation of the vaporization cooling on heat exchangers as cited in U SPTO porovisional patent application 61681973 Aug. 10, 2012.

Claim (5) A method where the upgrade kit controller and electronics functions entirely independent of the hysteretic controller of the existing equipment for the upgrade. The control provided by the upgrade kit operates transparently with the existing hysteretic controller.