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### Guidelines for Charging HFC-245fa to ORC Systems

This guideline provides general directions for char ging HFC-245fa to ORC systems. This guideline is not meant to be a substitute for specific OEM instructions for leak checking, evacuation, or charging. It is always pre ferred that specific OEM instructions

are followed when available.

Positive-Pressure Leak Check

Once the system is assembled it can be positive-pre ssure leak checked. It is important not to exceed any component pressure ratings when p ressure testing. Consult the ORC equipment manufacturer to determine the acceptable pressure level that can be used for leak checking. The following information is gener al guidance. The system should be pressurized to 860kPa using dry nitrogen. An ultra sonic leak detector is then used to detect leaks. Alternatively, a refrigerant such as R-134a can be used as a trace gas when an electronic refrigerant leak detector is used. T his can be accomplished by adding R134a refrigerant to a pressure of 69kPa and then ad ding dry nitrogen until the pressure is 860kPa. A leak detector capable of detecting HFC r efrigerants would then be used to locate any leaks. After leak check, the refrigeran t/nitrogen mixture would be recovered. Then the system would need to be evacuated to remov e any remaining non-condensables

and moisture.

Evacuation/Vacuum Leak Check

Evacuate system to less than 1,000 microns (mercury ) pressure. Use a good vacuum gauge, such as an electronic vacuum gauge to measur e pressure. Place the gauge at the opposite end of the vacuum train as far as possible from the vacuum pump. (See Figure 1.) After evacuation, isolate the vacu um pump from the system and monitor the system pressure for 10 minutes. If vacuum pres sure should not rise more than 300 microns in 10 minutes, the system is tight. If vac uum pressure rises more than 300 microns and then becomes steady, there is still moi sture in the system. Additional evacuation is required. If pressure rises continuo usly, there is a leak in the system.

For small systems, it may not be necessary to break vacuum using HFC-245fa vapor. To minimize the likelihood of heat exchanger tube icin g in large systems, break vacuum by first charging HFC-245fa vapor until system pressur e is above 11.0 inches of mercury vacuum. (See Figure 3.) Be sure to maintain cooli ng water flow or fans (air-cooled systems) during charging. A charging line is conne cted between the vapor access port of the source cylinder to an appropriate vapor connect ion on the system.2

Charging HFC-245fa

Gravity Charging From Single Port Cylinders

Connect the HFC-245fa cylinder to the system as sho wn in Figure 2. Elevate the cylinder so that it is above the height of the liquid reserv oir receiving the charge. If the cylinder temperature is cooler than the system temperature, it may be necessary to warm the cylinder. A commercially available cylinder heatin g apparatus with appropriate temperature controls such as cylinder heating blank et may be used. Alternatively, warm water (125F or less) can be used to heat the cylind er.

Pump-Assisted Charging From Single Port Cylinders

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A gear pump can be used to transfer liquid HFC-245f a. Graphite or stainless steel gears are acceptable. Polymeric gears such as PTFE may s well enough to bind the gears and

are thus not recommended.

Caution: Do not operate the transfer pump with the downstream service valve closed. “Dead heading” the pump can lead to component damag e or failure. Serious injury can occur depending on the mode of failure.

When using a pump to assist with liquid transfer, a transfer line is connected between the HFC-245fa source cylinder liquid port and the pump suction. A transfer line is connected between the pump discharge and the liquid side of t he system. If possible, position the pump lower than the HFC-245fa source cylinder so ad equate pump suction head is maintained. If the HFC-245fa source cylinder can not be elevated above the height of the liquid reservoir receiving the charge, it may b ecome necessary to warm the cylinder in order to create an adequate pressure differentia l. The previous section discusses cylinder heating methods. Additionally, if pump ca vitation occurs, the transfer line between the pump and source cylinder can be formed into a coil and immersed in water ice or dry ice to prevent pump cavitation. (See Fi gure 2.)

Charging from Containers having Separate Liquid and Vapor Ports

When the refrigerant source container is equipped w ith both liquid and vapor ports, the push-pull liquid transfer method can be used. (See Figure 3.) A vapor line is connected between the vapor port of the HFC-245fa source cont ainer and the vapor side of the system. A section of liquid transfer line is conne cted between the HFC-245fa source container liquid port and the pump suction. A sect ion of liquid transfer line is connected between the pump discharge and the liquid side of t he system.3

Other Equipment

A refrigerant recovery unit may be used in place of a liquid transfer pump. Consult the recovery equipment manufacturer for the recommended connections and procedures. A refrigerant recovery unit provides a convenient mea ns to recover liquid from the liquid transfer line after charging been completed.

ORCS Vapor Service Port Vacuum Pump* Figure 1 -System Evacuation

Vacuum gauge (locate away from vacuum pump)

* If a recovery/charging unit is used instead of a va cuum pump, consult the recovery equipment manufactu rer for recommended evacuation connections and procedure. Vent to a safe outside location

ORCS Vapor Service Port Vacuum Pump* Figure 1 -System Evacuation

Vacuum gauge (locate away from vacuum pump)

* If a recovery/charging unit is used instead of a va cuum pump, consult the recovery equipment manufactu rer for recommended evacuation connections and procedure. Vent to a safe outside location

ORCS Vapor Service Port

Liquid Service Port Pump (Optional)

Wet or Dry Ice (Optional) Cylinder

Liquid Port Figure 2 - Single Port Cylinder : Gravity or Pump-As sisted Charging

Warming of cylinder may be required – a commercially available cylinder heating blanket
is recommended. Cylinders that do not have a dip tube Need to be inverted to deliver liquid.

Vacuum Gauge Evacuated system

ORCS Vapor Service Port

Liquid Service Port Pump (Optional)

Wet or Dry Ice (Optional) Cylinder

Liquid Port Figure 2 - Single Port Cylinder : Gravity or Pump-As sisted Charging

Warming of cylinder may be required – a commercially available cylinder heating blanket
is recommended. Cylinders that do not have a dip tube Need to be inverted to deliver liquid.

Vacuum Gauge Evacuated system4

Disclaimer Although all statements and information contained h erein are believed to be accurate and reliable, the y are presented without guarantee or warranty of any kind , expressed or implied. Information provided herein does not relieve the user from the responsibility o f carrying out its own tests and experiments, and t he user assumes all risks and liability for use of the info rmation and results obtained. Statements or suggest ions concerning the use of materials and processes are m ade without representation or warranty that any suc h use is free of patent infringement and are not reco mmendations to infringe on any patents. The user sh ould not assume that all toxicity data and safety measur es are indicated herein or that other measures may not be required. ORCS

Vapor Service Port

Liquid Service Port Pump*

Wet or Dry Ice (Optional) Figure 3 - Dual Port Cylinder: Push/Pull Charging

Liquid Port Vapor Port

HFC-245fa cylinder

* If a recovery/charging unit is used instead of a pu mp, consult the recovery equipment manufacturer for recommended connections and charging/recovery procedures. 1) For large systems, break vacuum by first charging vapor to a system pressure of 11.0 inches of mercu ry vacuum. 2) Open cylinder liquid port and valves along liquid transfer line, then start pump to begin charging li quid.

Vacuum Gauge

ORCS

Vapor Service Port

Liquid Service Port Pump*

Wet or Dry Ice (Optional) Figure 3 - Dual Port Cylinder: Push/Pull Charging

Liquid Port Vapor Port

HFC-245fa cylinder

* If a recovery/charging unit is used instead of a pu mp, consult the recovery equipment manufacturer for recommended connections and charging/recovery procedures. 1) For large systems, break vacuum by first charging vapor to a system pressure of 11.0 inches of mercu ry vacuum. 2) Open cylinder liquid port and valves along liquid transfer line, then start pump to begin charging li quid.

Vacuum Gauge