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2 This manual may not be reproduced in whole or part without prior permission from EMBRACO /36

3 Index Page 1. Introduction Compressor Ranges Applications Starting Torque Classification Electric Motor Types Voltages and Frequencies Nomenclature Compressor Model Compressor Label Compressor Electrical Components Wiring Diagram Basic Dimensions Compressor Fixation Compressor Cooling Types Oil Charge Compressor Handling Preparation of Refrigerating System Components Guide for the Use of R R 744 Properties Refrigerant Purity System Components Compatibility and Contamination Moisture Filter Dryer Expansion Device Refrigerant Charge Determination Evaporator and Gas Cooler /36

4 Oil Return to Compressor High Pressure Limit Control Equalization Time for Suction and Discharge Pressures Welding of Connection Tubes Installation of Filter Drier Vacuum Operation Refrigerant Charge Procedure Refrigerant Leakage Control Electric Supply Compressor Running Limits Maximum Temperature of Electric Motor Stator Windings Discharge Gas Maximum Temperature Discharge Gas Maximum Pressures Suction Gas Overheating Running Time Cycling Compressor Operating Envelope Safety and Reliability Approval of Customer Application AFFIDAVIT Note: After replacement, the compressor and its accessories must have proper processing, and the components must be recycled according to the material group (ferrous, non-ferrous, polymers, oils,...) directives. These recommendations are intended to minimize the adverse impacts that may be caused to the environment /36

5 1 Introduction The design of a refrigeration system is a type of problem solving that involves many considerations and warnings. Design invariably requires the critical evaluation of the solutions by considering factors such as economics, safety, reliability, and environmental impact, before choosing a course of action. The vapour compression cycle has dominated the refrigeration market to date due to its advantages: high efficiency, low toxicity, low cost, and simple mechanical embodiments. In recent years, environmental aspects are becoming an increasingly important issue in the design and development of refrigeration systems. Specially in vapor compression systems, the banning of CFCs and HCFCs due to their environmental disadvantages has made way for other refrigeration technologies which until now have been largely ignored by the refrigeration market. As environmental concerns grow, alternative technologies which use either inert gasses or no fluid at all become attractive solutions to the environment problem. Regulations prescribe that CFCs and also HCFCs should no longer be used as refrigerants and HFCs seem to be only an interim solution. Looking for final choices and furthermore, taking into account regulations for greenhouse gas emissions, natural fluids become a promising alternative as refrigerants. Some of these refrigerants, like hydrocarbons and ammonia, are good choices from the point of view of performance, but they have flammability and toxicity characteristics. These characteristics lead these choices to be often refused by some end users, besides their vast use in domestic /36

6 (hydrocarbons) and industrial (ammonia) refrigeration. If non-toxic and non-flammable refrigerants are required, the focus emerges upon carbon dioxide (R 744 or CO 2 ). The use of R 744 as a refrigerant is recently considered for application in low capacity transcritical refrigeration cycle. Due to the properties of R 744, the pressure ratio of the refrigeration process is rather low compared to common refrigerant fluids, while the pressure difference is high. Furthermore, the volumetric capacity of R 744 is higher than traditional refrigerants. Those facts result in special demands regarding the design of suitable components, specially the driving mechanism, to be able to meet the requirements regarding the overall system performance, reliability and safety. This document describes the features of the R 744 compressor developed by Embraco and all the information disclosed can be altered, as the knowledge on the application advances. The intention is to provide main information to our customers about R 744 compressor application and instructions/best practices on how to handle the R 744 compressors supplied. We recommend referring always to local safety standards and regulations. In the event any further information or clarification is needed, please contact Embraco technical team /36

7 2 Compressor Ranges Table 1 indicates the applications available for the R 744 compressors you are receiving: Table 1 - Compressor series - R 744 application Series Application LBP MBP/HBP AC EK No Yes No 3 Applications Table 2 - Applications Type MBP-HBP Description Medium/High Back Pressure Models at medium/high evaporating temperatures, suitable for applications with evaporating temperatures higher than -20 o C and lower than 10 o C /36

8 Starting Torque Classification 4 Table 3 describes the types of starting torque for the electrical motors of Embraco R 744 compressors currently available. Table 3 - Electrical motor starting torque classification Type HST High Starting Torque Description MBP/HBP applications with CSR electric motor. Execution suitable for systems with expansion valve or capillary tube, with maximum unbalanced pressures at start up of 10 bar. Electric Motor Types 5 Table 4 describes the different types of electric motors used in Embraco R 744 compressors. Table 4 - Electrical motor types Type CSR Description Capacitive Start & Run This motor type has high starting torque (HST) and can be applied either in systems with capillary tube or expansion valve (maximum differential pressure is 10 bar). The motor is characterized by a start capacitor with suitable capacitance connected in series with the start winding to get a high starting torque. A starting device (PTC) disconnects the start winding at the end of the start up. A permanent connected run capacitor is used to improve its efficiency /36

9 6 Voltages and Frequencies Table 5 indicates the various rated voltages and frequencies with the corresponding operating ranges and minimum starting voltages of the compressors. Table 5 - Voltages and frequencies Embraco Code Rated Voltage & Frequency Voltage Working Hz A V 50Hz 1~ V U 220V/60Hz 1~ V G 115V 60Hz 1~ 103V - 127V Q 100V 50/60Hz 1~ 90V - 110V 90V - 110V 7 Nomenclature Compressor Model Basic Type Efficiency Level 1 - LBP - LST 2 - LBP - HST 5 - M/HBP - LST 6 - M/HBP - HST Cooling Capacity The first digit is the number of zeros that must be added to the last two digits to obtain the cooling capacity (approx) in kcal/h at 50Hz. Eg.: 210 = 1000 kcal/h at 50Hz Refrigerant EK S CD CD = R 744 (CO 2 ) E I V = Standard Efficiency = Improved Efficiency 1 st Generation = Improved Efficiency 2 nd Generation = Improved Efficiency 3 rd Generation S = Improved Efficiency 4 th Generation T = Improved Efficiency 5 th Generation U = Improved Efficiency 6 th Generation /36

10 Compressor Label 8 G C J E D 10 mm B I F H A A - Traceable serial number B - Compressor code / Part number C - Compressor designation D - Locked rotor amperage - LRA Frequency - Hz Refrigerant - R 744 Number of phases - 1 PH Nominal voltage of compressor - VAC E - Logos indicate institute approval of compressor F - Bar code 39 (ratio 3:1 and 6.5 mils) G - Paper: White Graphics: Black Size: 70 x 38 mm (2.76 x 1.50 ) H - Date of manufacture I - Manufacturing plant J - The orange band is the visual identification used for 2XX V, 2XX-2XX V 60Hz compressors. The green band is used for V~ 50Hz compressors. The white band is used for 1XX V~, V~ compressors. Compressor Electrical Components 9 The intended electrical components for Embraco R 744 compressor electric motor are indicated in Table 6. These components may be supplied by Embraco or directly by the manufacturer. In the event the customer decides to buy the electrical components directly from the manufacturer, Embraco s electrical components approval process shall be followed /36

11 Table 6 - Electrical components Motor Type Overload Protector Current Relays Starting device Voltage Relays Capacitors PTC Start Run CSR Yes No No Yes Yes Yes Compressors can have different electrical components according to their version. IT IS IMPORTANT TO USE THE COMPONENTS SPECIFIED ON THE DATA SHEET OF THE COMPRESSOR. 10 Wiring Diagram Figure 1 - Wiring diagram In the picture above X is connected to terminal 1. Terminal 2 is connected to neutral. Line is connected to the overload protector /36

12 Basic Dimensions 11 All dimensions in millimeter [mm]. Suction connector Figure 2 - Frontal view Process connector: must be sealed and must not be used. Discharge connector Figure 3 - Superior view Figure 4 - Inferior view /36

13 12 Compressor Fixation Figure 5 indicates the wrong and right ways of fixing the compressor to the system. Bolt Nut Washer Sleeve Compressor base Cabinet base Rubber dampers INCORRECT CORRECT Figure 5 - Rubber dampers /36

14 Compressor Cooling Types 13 Table 7 lists the cooling type intended for Embraco R 744 compressor. Table 7 - Cooling type for Embraco R 744 compressor Type F Description Fan cooling: the compressor requires forced cooling through the use of a fan. The fan cooling compressor requires the use of a fan cooler (normally inlet type) positioned in such a way that the flow is introduced to the compressor perpendicularly to the cylinder head axis. The thermal protector, if cooled by the air flow, may not trip and may not protect the compressor properly. We suggest maintaining a distance of 0.2 to 0.3 m from between the compressor and the fan blades. The fan cooler can be chosen according to the air flow indicated in Table 8. Table 8 - Fan cooler characteristics Forced Cooling Free air flow 270 m 3 /h or air speed of 3 m/s /36

15 14 Oil Charge All Embraco R 744 compressors are always supplied with lubricant oil, as indicated in Table 9. The maximum humidity content in the oil is 15 ppm for the moment of injection in the compressor. Table 9 - Lubricant oil used in Embraco R 744 compressor Series Type Oil Type 40 o C [cst] EK Polyolester 68 All Embraco R 744 compressors are charged with 150 cm 3 of lubricant oil. The minimum amount of oil in the compressor that guarantees the correct lubrication is 100 cm 3. Oil quantities below the minimum prescribed level will not allow the oil pump to prime and will cause wear, leading to a possible seizure of the mechanical parts /36

16 Compressor Handling 15 The following figures show what is allowed in terms of compressor handling during assembly and transportation of compressor and refrigeration system. The indicated angles are maximum values. Forbidden handling is marked by a X and may cause damage to the compressor if performed. In any case it is NOT PERMITTED TO TURN THE COMPRESSOR UPSIDE DOWN. Figure 6 - Ways of handling with the compressors during assembly and transportation /36

17 16 Preparation of Refrigerating System Components Cleaning (solid substances and non-condensable) and the reduced moisture in all the components of the refrigeration system are the primary concerns for good running and life of the compressor. Embraco suggests the use of system components such as tubes, gas coolers, evaporators, oil separators, liquid receivers, valves, capillaries, etc., with moisture, solid residues and non-condensable gases contents reduced by 50% compared to what is prescribed by DIN 8964 Standard - and free of contaminants like chlorine based compounds, as well as non ester based oils. Components shall remain sealed as long as possible before their assembly, and welding must be performed no later than 10 minutes after assembling the components. To avoid residues during the welding process, it can be useful to blow out these components with nitrogen or dry air, with a dew point lower than -40 o C before using them /36

18 Guide for the Use of R This section presents some guidelines for the use of R 744 as refrigerant fluid. Due to the vast differences between systems and respective working fields typical of each application, the reliability of the equipment shall be defined by appropriate life and field tests. Embraco technicians are available for support of systems design, tests and validation of the applications before starting field tests and mass production. All operations related to the use of refrigerants shall be performed in accordance with local laws, international standards and rules related to this subject R 744 Properties Basic thermophysical properties are given in Table 10 and ecological characteristics are given in Table 11. Table 10 - R 744 physical characteristics Molecular Weight kg/kmol Ref.: R 134a = kg/kmol Critical Temperature o C Ref.: R 134a = o C Critical Pressure bar Ref.: R 134a = bar Boiling Point o C Ref.: R 134a = o C Table 11 - R 744 ecological characteristics ODP (Ozone Depletion Potential) 0 Ref.: R 134a = 0 GWP (Global Warming Potential) 1 Ref.: R 134a = 1300 (100 years) /36

19 Refrigerant Purity The refrigerant recommended to be used both for tests and manufacturing shall follow the purity specifications in Table 12. Table 12 - R 744 purity degree specs Purity Carbon Dioxide Water Content Nitrogen Acid (Sulphur Dioxide) 99.95% Vol. max 20 wtppm < 5 ppm 0.1 wtppm System Components Compatibility and Contamination All refrigeration system component materials shall be compatible with the refrigerant and lubricant used in the compressor. Substances containing chlorine, paraffin and silicone are not approved. Particular attention must be paid to internal cleanliness of the system. The above mentioned substances as well as any solids residues (dust, metal particles, etc...) must not be introduced into the system. It is recommended the maximum level of contamination by other substances than the ones listed above to be 50% less than what is prescribed in DIN Moisture In order to avoid problems that can shorten the life of the refrigeration system, use components that are supplied internally, dried and properly sealed, to prevent the entrance of moisture. These components should remain sealed until they are used /36

20 It is recommended to avoid leaving the compressor and components exposed to the ambient for more than 10 minutes. If there is any doubt regarding the presence of moisture in a component, it may be dried by blowing dry air (with a dew point below -40 o C) through the internal surface for a sufficient period of time. It is recommended to maintain moisture content in the system 50% lower than what is prescribed by DIN The level of moisture present in the refrigeration circuit shall be below 40 ppm and after the system has been operating, the filter dryer should remove moisture from the system from a level below 20 ppm Filter Dryer It is strongly recommended to use a filter dryer that is compatible with refrigerant R 744 and the compressor oil. Always refer to the manufacturer of the filter dryer for proper selection. The filter dryer also has to comply with the same high pressure specification as the gas cooler. Solid core filter dryers are the preferable choice, although molecular sieves grains are also possible to be used. Field and life tests are recommended for approval of the filter dryer. Consequences of high moisture content in the system are shown on table /36

21 Table 13 - Inconvenient caused by moisture in the system 1 Ice build-up 2 Acid build-up 3 Oil contamination Reduces the cross-sectional area of the capillary tube, or expansion valve, up to their complete obstruction. Causes serious problems in the compressor and to the molecular sieve of the filter. Typical marls and consequences are: Copper plating of valve plate, valve reeds, crankshaft bearings, etc. Etching of electric motor insulation by acids, with burning of motor windings. Destruction of the filter with disintegration of molecular sieve and build-up of dusts. Wear of reciprocating and rotating mechanical parts. Causes acidification and reduction of its lubricating power, with change of oil colour (brown). It can cause build-up of sludge, with subsequent poor lubrication of compressor Expansion Device Capillary Tubes: In case where a capillary tube is chosen as the expansion device, Embraco suggests to use the correlation from the article below as a first trial of sizing the capillary tube. HERMES, C. J. L.; SILVA, D. L.; MELO, C.; GONCALVES, J. M.; ZIMMERMANN, A. J. P.. TRANSCRITICAL CARBON DIOXIDE FLOW THROUGH ADIABATIC CAPILLARY TUBES. PART II: MATHEMATICAL MODELING. In: 8 th IIR Gustav Lorentzen Conference on Natural Working Fluids, 2008, Copenhagen. Proc. of the 8 th IIR Gustav Lorentzen Conference on Natural Working Fluids. Copenhagen: Danish Technological Institute, For every refrigeration system, the optimal sizing of the capillary tube shall be performed in laboratory following an appropriated procedure, in order to obtain the best working conditions and to avoid the return of liquid refrigerant to the compressor /36

22 It is not recommended to use a capillary tube with an internal diameter smaller than 0.6 mm. Expansion Valve: Should be selected according to the working temperatures and pressures characteristics of refrigerant R 744 and the refrigeration system it will be applied to Refrigerant Charge Determination Generally, the quantity of refrigerant R 744 introduced into the system is increased by 35% to 50% compared to the required charge of R 134a when using standard finned tube heat exchangers and the internal volume of the system sealed unit is kept the same. If the original HFC system has a suction accumulator, then the information above is not valid. One can start the charging determination procedure using the same charge as the R 134a system and check the performance. Then it is possible to decide on which way to go. For each system, the optimal refrigerant charge shall be determined in laboratory, following the appropriated procedure, in order to obtain the best working conditions and to avoid the return of liquid refrigerant to the compressor. The maximum allowed refrigerant charge in a system using this compressor series is 500 g of R 744. Systems approaching the maximum refrigerant charge should be tested for flooded start and liquid slugging /36

23 Evaporator and Gas Cooler Gas Cooler: It is mandatory to perform hydrostatic pressure tests, in which the burst pressure must comply with IEC standard. Note: For eventual tests on existing HFC or HC systems, the original condenser must be replace by a gas cooler with the aforementioned characteristics. Similar replacement is necessary for all other components of the system. Copper tubes can be used as long as the hydrostatic specifications above are complied. Evaporator: The mechanical strength of the evaporator shall comply with IEC standard. Copper tubes can be used as long as the hydrostatic specifications above are complied. System Volumes Balance: System internal volumes balance is needed, and it is more important when using R 744. An example of improper balance is when the high pressure side internal volume is too small compared to the low pressure side. This can lead to extreme operating conditions during normal pull-down and when abnormal situations occur i.e.: gas cooler fan failure, capillary tube blockage, also gas cooler area reduction due to fouling, etc. These extreme operating conditions can put in danger both reliability and safety of the refrigeration system. Internal volume of the high pressure side shall be large enough to lead to a maximum density of 0.65 g/cm3 when all the refrigerant charge is distributed in this volume /36

24 Oil Return to Compressor Due to its intrinsic characteristics, CO 2 compressors have higher OCR (Oil Circulation Rate) than HFC compressors. Therefore, it is very important to assure that there is no oil trap in the system circuit that can cause compressor failure. In order to do so, siphons and adverse height differences must be avoided. Top to down circuit is recommended on the heat exchangers. Specific tests, continuously running with low evaporating temperatures, if applicable, are recommended to check the oil return to the compressor. It is also recommended that the minimum flow speed shall not be less than 2 m/s, in order to allow the oil to flow back to the compressor together with the refrigerant. The figures below show examples of recommended and nonrecommended circuits. Figure 7 - Non-recommended circuit - oil trap Figure 8 - Recommended circuit /36

25 High Pressure Limit Control The system shall be tested in abnormal working conditions like high ambient temperatures, high side heat exchanger fan failure, gas cooler area reduction due to fouling, and/or expansion device failure. The maximum observed discharge pressure in abnormal working conditions shall not exceed 30 bar of the limit values described in the chapter Discharge Gas Maximum Pressures. It is strongly recommend the installation of a pressure safety device (i.e. pressure switch) to limit the discharge pressure to the aforementioned value. The compressor overload protector is not a pressure safety device and may not turn off the compressor in case of overpressure Equalization Time for Suction and Discharge Pressures Typically, the time for the suction and discharge pressures to equalize ranges from 3 to 6 minutes depending upon the application (HBP/MBP). This owes to the different appliances that have been tested in our application laboratory. Compressor off periods lesser than 5 minutes must be avoided when using capillary tubes. This is to allow proper equalization, and also for the PTC to be cooled down, guaranteeing the compressor start-up. When using expansion valves, it is important to check the values of allowable unbalanced pressures during compressor start-up. It is recommended that the system equalizes right before starting the compressor, in case of electronic controlling /36

26 Welding of Connection Tubes 18 During brazing of the connectors on the compressor copper-plated steel tubes, the following instructions shall be observed: DO NOT ALLOW the torch flame to reach the housing during the welding of the compressor tube, in order to avoid overheating, damages to welding, and oil carbonization on the compressor s internal walls. DO NOT ALLOW the torch flame to approach the hermetic terminal, in order to avoid the cracking of the glass insulating material of the three pins and subsequent gas leaks. The welding of compressor connectors (copper-plated steel) to copper tubes can be done with 38% silver content welding material. Proper welding is characterized by a good penetration of weld material, to guarantee a good mechanical resistance, and no leaks from the connection. These characteristics are obtained with the use of suitable materials and a well performed welding (welding should be performed only by qualified technicians), as well as with a correct sizing of the tubes to be coupled, in order to guarantee the optimal clearance. A tight clearance determines a bad penetration of welding material, while a large clearance causes penetration of welding material and de-oxidizers inside the tube and compressor. Recommended value of diametrical clearance ranges from 0.1 mm to 0.6 mm. The most common values used by Embraco range between 0.15 mm to 0.3 mm /36

27 To limit internal contamination by de-oxidizing flux, we suggest applying small quantities of de-oxidizer on the connection tube after connecting it to the compressor tube. During the welding operation, avoid overheating of the connection. This reduces the formation of oxide contaminants inside the tubes. It is suggested, during the welding operation, to blow nitrogen through the tubes. With the use of R 744, the possibility of refrigerant gas leaks through defective welds is increased, due to its molecule size and high pressure levels associated to this refrigerant. 19 We also suggest taking particular care in performing welding and leak detection, which must be carried out with equipment that is sensitive to the refrigerant type used. Installation of Filter Drier Make a small bend in the capillary to prevent it from going too far into the filter, approximately 15 mm (0.59 ), see figures 9 and 10; Using a clamp, open up the two sides of the filter drier when brazing; Braze the filter into the gas cooler and capillary. Do not unnecessarily heat the body of the filter dryer, and take great care not to block the tubes. Install the fast coupling to make a vacuum on the high pressure side; The filter dryer must be installed in the vertical position with the capillary at the bottom (see figure 11) /36

28 This position prevents the desiccant grains from rubbing and releasing residues. It also helps to equalize pressure faster (capillary systems). Figure 9 - Capillary tube 15 mm (0.59 ) Figure 10 - Inserting the capillary into the filter drier Gas cooler Filter Drier Capillary! Important Figure 11 - Filter drier Brazing - Do not forget to clean well the surface to be brazed. Remember: blockage of the outlet tube will damage the compressor valve system /36

29 20 Vacuum Operation It is critical to perform a proper evacuation of the refrigeration system, in order to ensure proper running of the refrigerating machine and to preserve the life of the compressor. A proper evacuation process assures that the air and moisture contents are below the allowed limits. Based on the fact that POE oils are highly hygroscopic, the vacuum procedure requires great care. It is recommended that vacuum is made on both sides of the system with the vacuum level below 0.05 mbar for ten (10) minutes. The vacuum level must be measured in the refrigeration system, not in the pump. Use hoses as short and with large diameter as possible. It is recommendable to install a check valve at the inlet of the vacuum pump. Note: To avoid irreparable damages to the compressor, do not ever start it under vacuum (without refrigerant charge) /36

30 Refrigerant Charge Procedure 21 Laboratory controlled conditions: After the vacuum operation, the system must be charged with the refrigerant as follows: 1. Inject all refrigerant charge through a connection at the inlet of the capillary tube or dryer. If an expansion valve is used, one has to assure that it is open during the charging procedure, and at least for five (5) minutes later. 2. If it is not possible to follow procedure number 1 above: For a correct charge we suggest, after carrying out the vacuum, to pump part of the refrigerant into the low side of the system (as far as possible from the compressor suction port) to break the vacuum; then start the compressor to draw the remaining part of the charge. Vapour phase refrigerant must be used in this procedure in order to avoid liquid compression. Mass production conditions: After the vacuum operation, inject all refrigerant charge through a connection at the inlet of the capillary tube or filter dryer. If an expansion valve is used, same place is recommended and one has to assure that the valve is open during the charging procedure, and at least for 5 minutes after the completion of refrigerant injection. The process connector shall not be used by the refrigeration system manufacturer for any process. This tube is only used for oil charge during the compressor manufacturing process, and must be sealed by the refrigeration system manufacturer. Use charging equipment suitable for R /36

31 22 Refrigerant Leakage Control A refrigeration system can work normally for the entire life of the compressor, only if attention is given to proper installation. One of the most important aspects is the absence of refrigerant leaks. It is estimated that a 10% leak of the refrigeration charge over 10 years of running the compressor will still allow for proper running of the refrigerating system. With the new refrigerant R 744, the possibility of leak through improper welding increases, due to the molecular size of R 744 combined with the very high pressure levels. Thus, it is critical that accurate controls of leak are performed on the welding points with methods and equipment suitable to the applied refrigerant type. 23 Electric Supply The compressor assembled in the refrigeration system shall be connected to a voltage supply within the limits indicated in the chapter Voltages & Frequencies. Due to voltage drops in the supply circuit, the voltage must be measured at the compressor hermetic terminal. The compressor shall be grounded /36

32 Compressor Running Limits 24 Sizing of the components of the refrigerating system must be performed in a way that the limits indicated below are not exceeded. During operation in the field, the system can face some factors that worsen the working conditions, such as gas leaks, reduction of the gas cooler effectiveness due to fouling, et. Owing to these factors, it is recommended to size the system with a good margin of safety, allowing the system to operate within the prescribed limits Maximum Temperature of Electric Motor Stator Windings 130 o C max, under normal running conditions. 140 o C max, under tropical and extreme voltage conditions Discharge Gas Maximum Temperature Maximum temperature indicated in Table 14, measured in the discharge tube at a distance of 50 mm from compressor housing, under continuous running conditions Discharge Gas Maximum Pressures Maximum discharge pressure under continuous running and under pull-down is indicated in Table /36

33 Table 14 - Discharge gas maximum limits Maximum Discharge Pressure Maximum Gas Discharge Temperature bar (abs) kgf/cm 2 (abs) o C Suction Gas Overheating Maintain the suction gas temperature at same levels as HFC s (min 3 o C), taking care that there is no liquid return to the compressor. Do not exceed 32 o C at the inlet of the compressor (measured in the suction line 200 mm far from the suction tube) Running Time Size the systems for maximum 80% of normal running time. 100% is allowed only under heavy duty and high ambient temperature conditions Cycling The systems shall be sized for maximum 5 cycles / hour (average cycling) when empty. Compressor with PTC starting device shall be re-started after a minimum time of 5 minutes from the off period. The trip of the thermal/current protection requires that the compressor re-start occurs after the necessary time for the protector to reset /36

34 Compressor Operating Envelope The Compressor Operation Envelope ( COE ) is defined by the diagram presented below and indicates the limits of evaporating, condensing, ambient, and return gas temperatures. The compressor can operate only within the limits of evaporating temperatures and discharge pressures defined by the dashed area, at the indicated conditions of ambient and return gas temperatures. It is important to point out that in the event the system operates outside the COE, it will operate at higher pressures and temperatures, and can cause early defects in the compressor. Figure 12 - Compressor operating envelope /36

35 Safety and Reliability Approval of Customer Application Before starting any mass production of the compressor R 744 application, it is strongly recommended to accomplish the following testing program: 1. Evaluate abnormal operating conditions and failure mode combinations of the Customer system; 2. A first trial field test shall be made with twenty (20) units (the whole refrigeration system) manufactured as close as possible to the final Customer manufacturing process. The duration of this first field test shall be of three (3) months minimum. After that, a TDA (Tear Down Analysis) of five (5) units is recommended; and 3. A second trial field test shall be made with one hundred (100) units (the whole refrigeration system) manufactured following the final Customer manufacturing process. The duration of this second field test shall be six (6) months minimum /36

36 AFFIDAVIT We hereby, on behalf of, a company duly organized and existing under the laws of, with head office located at ( Company ), declare that we received this R 744 Application Manual, read it and have already clarified with the engineers from Whirlpool S/A - Embraco Compressor and Cooling Solutions Business Unit, each and every technical information set forth hereinabove, specifically regarding the possible safety consequences and impacts of using and encompassing the CO 2 Compressor into its system. We also declare and comprise that the contents of this R 744 Application Manual will be deployed among all technicians and engineers, who are Company s employees and/or services providers. Furthermore, we completely understand that this R 744 Application Manual sets forth all the procedures and cares to avoid any damage consequence of using the CO 2 Compressor during and thereafter its application into our products. Thus, we agree to endeavour our best efforts to comply with all the guidelines and instructions. PLACE: DATE: SIGNATURE: NAME: TITLE: /36

37 AFFIDAVIT We hereby, on behalf of, a company duly organized and existing under the laws of, with head office located at ( Company ), declare that we received this R 744 Application Manual, read it and have already clarified with the engineers from Whirlpool S/A - Embraco Compressor and Cooling Solutions Business Unit, each and every technical information set forth hereinabove, specifically regarding the possible safety consequences and impacts of using and encompassing the CO 2 Compressor into its system. We also declare and comprise that the contents of this R 744 Application Manual will be deployed among all technicians and engineers, who are Company s employees and/or services providers. Furthermore, we completely understand that this R 744 Application Manual sets forth all the procedures and cares to avoid any damage consequence of using the CO 2 Compressor during and thereafter its application into our products. Thus, we agree to endeavour our best efforts to comply with all the guidelines and instructions. PLACE: DATE: SIGNATURE: NAME: TITLE: /36

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39 If after these instructions you still have doubts, please do not hesitate to call us. Write to Embraco: Process and Product Technology Group Group for Assistance in Application Rua Rui Barbosa, Caixa Postal 91 CEP Joinville - SC - Brazil /36

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