Carrier 09RH Flywheel Compressor Dimensions, Flywheel Width Pitch Grooves, Model Number

GROOVES

F TO C OF FLYWHEEL L

Fig. 17 — Flywheel

Table 21 — Flywheel Data

*Refer to Fig. 17.

Table 22 — Flywheel — Compressor Dimensions

*Refer to Fig. 17.

BOOSTER COMPRESSORS FOR

REFRIGERANT 12, 22, 502, AND 507/404A

Booster Application Data — The following data sup- plements the single-stage compressor application data, and adds information pertaining to booster application only. Refer to the single-stage compressor data for all other information.

Rating Basis — All booster ratings* are given in refriger- ation effect and are based on:

1.Use of a liquid-suction heat interchanger. All liquid- suction interchangers should have a bypass connection on the liquid side so that adjustment can be made in event that too much superheating of suction gas causes exces- sive heating of compressor. This is especially true for Refrigerant 22, which has a higher compression exponent than Refrigerant 12.

2.The liquid refrigerant at Point A (Fig. 18) at satu- ration temperature corresponds to booster discharge pressure. This is often referred to as saturated inter- mediate temperature.

This occurs when booster discharge gas is condensed in a cascade (refrigerant-cooled) condenser, or when using an open flash-type intercooler in a direct staged system. When subcooling of liquid takes place in a closed- type intercooler, it is not possible to bring liquid tempera- ture down to saturated intermediate temperature because of temperature difference required for heat transfer through the liquid coil. In this case, the compressor rating must be decreased 3% for each 10 degrees that liquid temperature at Point A is above the saturated intermediate temperature.

3.Use of only half of the standard number of suction valve springs per cylinder. All 5F,H compressors are factory assembled with the standard number of suction valve springs; therefore, one-half of the springs per cylinder must be removed in the field for booster applications.

4.Booster ratings are based on a 1750 rpm compressor speed.

*R-507/404A ratings are similar to R-502.

“R” Factors — In a multistage compression system, the intermediate or high-stage compressor must have sufficient capacity to handle the low-stage (booster) compressor load plus heat added to refrigerant gas by a low-stage machine during compression. Likewise, if an intermediate stage com- pressor should be used, the high-stage compressor must have sufficient capacity to handle the intermediate stage compressor load plus heat added to the refrigerant gas by an intermediate stage machine during compression.

To assist in the selection of higher stage compressors, Table 23 presents “R” factors that depict approximate required relationship between stages at various saturated temperature conditions.

To determine the required capacity of a higher stage com- pressor, multiply lower stage compressor capacity by the proper “R” factor from Table 23. Any additional loads handled at intermediate pressure must be added to this figure to arrive at the total higher stage load.

Multistage System Pointers — A staged system is essentially a combination of 2 or more simple refrigerant cycles. In combining 2 or more simple flow cycles to form a staged system for low temperature refrigeration, 2 basic types of combinations are common (Fig. 18).

DIRECT STAGING — Involves use of compressors, in series, compressing a single refrigerant.

CASCADE STAGING — Usually employs 2 or more refrig- erants of progressively lower boiling points. Compressed refrigerant of low stage is condensed in an exchanger (cascade condenser) that is cooled by evaporation of another lower pressured refrigerant in the next higher stage.

Safety Factors — Use of capacity safety factors in select- ing booster compressors must be a matter of judgment when making selection.

Factors that have a bearing on satisfactory compressor selections are: accuracy of load estimate, amount of safety factor included in the total load, degree of importance of meet- ing specified capacity at given condition, temperature level of operation and magnitude of refrigeration load. All of the factors must be recognized when considering the use of a capacity safety factor in selecting a booster compressor.

Figure 19 presents reasonable safety factors for use in selec- tion of booster compressors. These can be employed when it is not desired to establish a factor based on selector’s judgment.