Danfoss Intelligent Purging System (IPS 8) Ammonia

Legal Notice

This product information is a part of the documentation for the Danfoss scope of delivery and serves as product presentation and customer advisory service. It contains important information and technical data regarding the product.

This product information should be supplemented with the information about the industrial safety and health related regulations at the site of installation of the product. The regulations vary from place to place as a result of the statutory regulations applicable at the site of installation and are therefore not considered in this product information.

In addition to this product information and the accident prevention regulations applicable for the respective country and area where the product is used, the technical regulations for safe and professional work must also be observed.

This product information has been written in good faith. However, Danfoss cannot be held responsible for any errors that this document may contain or for their consequences.

Danfoss reserves the right to make technical changes during the course of further development of the equipment covered by this product information.

Illustrations and drawings in this product information are simplified representations. As a result of the improvements and changes, it is possible that the illustrations do not exactly match the current development status. The technical data and dimensions are subject to change. No claims will be accepted on the basis of them.

EU DECLARATION OF CONFORMITY

Danfoss A/S, 6430 Nordborg, Denmark, CVR nr.: 20 16 57 15, Telephone: +45 7488 2222, Fax: +45 7449 0949

Danfoss A/S, Refrigeration & Air Conditioning Controls, declares under its sole responsibility that the product category: Intelligent Purger System (Air Purger), Type designation(s): IPS 8, is in conformity with the following directive(s), standard(s) or other normative document(s), provided that the product is used in accordance with Danfoss instructions.

Machine Directive 2006/42/EC

• EN 378-2:2016 Refrigerating systems and heat pumps - Safety and environmental requirements - Part 2: Design, construction, testing, marking and documentation
• IEC 60204-1:2018 Safety requirements for electrical equipment for measurement, control and laboratory use - Part 1: General requirements

Pressure Equipment Directive 2014/68/EU (PED)

• EN 378-2:2016 Refrigerating systems and heat pumps - Safety and environmental requirements - Part 2: Design, construction, testing, marking and documentation
• Ammonia side (R717): Category A4P3. Fluid group: 1. PS = 40 bar. TS: -40 °C to 60 °C
• R452A side: Category 1. Fluid group: 2. PS = 28 bar. TS: -40 °C to 60 °C
• Ambient temperature: -10 °C to 43 °C

Electromagnetic Compatibility Directive 2014/30/EU (EMC)

• IEC 61000-6-2 Electromagnetic compatibility (EMC) - Part 6-2: Generic standards - Immunity standard for industrial environments (IEC77/488/CDV:2015)
• EN 61000-6-4 Electromagnetic compatibility (EMC) - Part 6-4: Generic standards - Emission standard for industrial environments

Note: EMC test performed with cable length < 30m.

Date: YYYY.MM.DD, Place of issue:

Issued by: Name: Su Cheong Ho, Title: Lead Design Engineer

Approved by: Name: Behzad Parastar, Title: Product Manager

Danfoss only vouches for the correctness of the English version of this declaration. In the event of the declaration being translated into any other language, the translator concerned shall be liable for the correctness of the translation.

ID No: 084R9456, Revision No: AA, Page 1 of 1

Technical Data

Field connected valves

See also Fig. 18

Ordering

* For closing system flange during system pressure testing

** See Fig. 1 and Fig. 10a

Introduction

The Danfoss Intelligent Purging System (IPS 8) is a stand-alone, self-contained purging unit designed to remove non-condensable gases (NC gases = air and other unwanted foreign gases) from industrial ammonia refrigeration systems.

The IPS control can handle up to 8 purge points automatically.

The ingress of NC gases into a refrigeration system is inevitable, regardless of the refrigerant, pressures, or temperatures. NC gases in the system will result in a decrease in system efficiency, both in terms of an increase in power consumption and reduced cooling capacity.

Due to having a different density than ammonia, the ingressed air will accumulate in specific areas of the system, where it can be removed using the Danfoss IPS 8.

The accumulation areas are identified in the Connection locations section, along with recommended connection principles.

The purger unit is an electronically controlled, self-contained R452A refrigerant system that runs independent of the main ammonia system and with only one flange connection to the ammonia plant.

The flanged opening allows the ammonia gas/NC gas mix access to the purger's heat exchanger, where it is split into ammonia condensate and NC gases. The ammonia condensate is returned by gravity to the main plant, while the NC gases are purged to the atmosphere through e.g. a water bath.

Through the flanged opening, the purger unit has access to the parameters from the ammonia plant required for full electronic control.

The unit runs automatically in 24-hour cycles, checking for the presence of NC gases and, if present, removes the NC gases.

To regain and retain the design capacity of the main ammonia system and prevent future air accumulation, it is highly recommended to install the Danfoss IPS 8.

Features

• State-of-the-art electronically controlled unit based on the Danfoss MCX controller platform
• Reduced power consumption of the ammonia plant
• Automatic purging response to NC gases in the refrigeration system
• Continuous and smart monitoring of differential pressure between the system refrigerant and the purger's refrigerant
• Smart purging that minimizes refrigerant (ammonia) release to the environment
• Self-contained unit operation, which functions independently from the main plant
• An operation log for easy purging cycle data monitoring
• Industry standard Modbus RTU communication for remote monitoring and system integration
• Reduced purging unit power consumption compared to other units due to on-demand operation only
• Load scheme to identify which purge point is removing most NCC
• Prepared to manage/control Bubbler
• Option to install LLS 4000 to protect IPS for high column of ammonia liquid
• Self-diagnostics for both unit and system operation to shut down in the event of malfunctions
• Cost-effective installation with few mechanical and electrical connections
• A fully brazed and leak-tested R452A cooling system, minimizing leakage risks
• A plug-and-play stand-alone design, which simplifies installation and commissioning while reducing potential errors
• No need for advanced settings
• A compact and easy-to-handle design
• IPS carry a registered patent
• With our solution of IPS 8 Air Purger combined with the Bubbler, we can help customers to keep machine rooms free of ammonia smelling, while IPS 8 is removing the non-condensable gases, and purging to the Bubbler

Working Principle

The Danfoss IPS 8 is factory-tested and ready to use in ammonia plants with a condenser pressure of more than 6,5 bar (94 psi). The purger is charged with 900 gram (31.7 oz) of R452A.

Only 1 mechanical connection is needed for the purger (see fig. 1). The flow of ammonia/NC gases from the main plant is done through the flange for ammonia (see 13 in Fig. 1 below), while the NC gas purge is done through the blow-off pipe after the purge restrictor (18).

Through the flange for ammonia (13), a mixture of ammonia gas and NC gases enters the heat exchanger (12) part of the purger.

The ammonia gas/NC gas mix is cooled down below the condensing temperature of the ammonia by the R452A circuit. At this point, ammonia gas condenses and returns by gravity to the ammonia plant whereas the NC gases accumulate in the heat exchanger (12) for subsequent purging.

By condensing the ammonia gas, a new ammonia/NC gases mix is naturally pulled through. This new mix is separated through a continuous process.

As the NC gas concentration in the heat exchanger (12) increases, the R452A heat exchanger pressure and temperature will simultaneously decrease.

The controller continuously monitors the R452A heat exchanger pressure as well as ammonia pressure and temperature. When the R452A pressure reaches a predefined pressure difference when compared with the ammonia pressure (temperature) it prepares to purge the NC gases through the solenoid valve (16). The blow-off is activated by the solenoid (16) and through appropriate piping/hosing, should be led into a water bath. This process is recommended to retain small amounts of ammonia (see Installation section).

Fig. 1 - Purger R452A lay-out

1: Compressor (900 gram (31.7 oz) R452A) controlled via Digital Output, DO1

1a: Compressor Cranck case heater

2: Thermostat for crankcase heater control

3: Discharge temp sensor R452A via Analog Input AI3, Pt 1000

3a: Suction temperature sensor R452A via Analog Input AI4, Pt 1000

4: Pressure safety switch

5: Condenser

6: Extraction fan

7: Pressure switch for Condenser Fan

8: Receiver

9: Filter

10: Sight glass

11: Expansion valve, R452A

12: Heat exchanger Ammonia/R452A

13: Welding Flange

14: Pressure transmitter R452A. Measured via via Analog Input AI1, Pressure transmitter, AKS 32R

15: Pressure transmitter R717. Measured via Analog Input, AI2, Pressure transmitter, AKS 2050

16: Main Purge Valve controlled via Digital Output, DO2

17: NC temperature sensor R717. Measured via Analog Input, AI5, Pt1000

18: Restrictor, purge line

19: LLS 4000 Liquid Level Switch. Accessory. Not included with standard IPS

Working Cycle

The Danfoss IPS 8 operates in 24-hour cycles, of which 45 minutes are dedicated to an R452A pull down. At power on, the pull down is initiated immediately. If no NC gases are detected during the 40 minute pull down, the system will close the solenoid valve at purge point 1 and open the solenoid valve at point 2. After a cycle time of 24 hours/N (Number of purge points), the compressor will pull down again condensing the ammonia. After 24 hours, all purge points have been vented one time.

To identify NC gases, the controller utilizes upper and lower thresholds for R452A evaporating temperature. If, during pull down, the temperature continues decreasing and the lower threshold is passed, the controller considers this to be a high concentration of NC gases and opens the purge solenoid valve. The purge valve will stay open until sufficient condensing ammonia is present to lift the R452A evaporating temperature above the upper threshold.

The compressor will continue running and if the temperature again decreases below the lower threshold, a new purge will be performed. This process will be repeated until the R452A heat exchanger temperature stays above the lower threshold for >40 minutes following the previous closure of the purge valve.

Parameter Table:

See complete Parameter List – Table 01

Fig. 2 - Power on & Cycle at no NC gases present: CST (compressor start time) and PDT (pull down time) are configurable

* Cycle (CST) = 24 hours/N (number of purge points)

Fig. 3 - Purging procedure - Low R452A evap. temperature detected during PDT: Thresholds are configurable

* If low evaporator temperature is detected (passing lower threshold), the purging procedure will be repeated immediately

Air Traps

For systems with low pressure liquid level control, the correct condenser/receiver installation is as shown in Fig. 4 and Fig. 5.

The discharge gas from the compressor (1) is led to the condenser (2) where it is condensed. The receiver (3) holds the liquid until there is a demand for liquid from the LP side, e.g., until the expansion valve (4) opens. If the expansion valve is closed, the liquid condensed in the condenser will need to be stored in the receiver and the level will increase. To ensure a free flow to the receiver, the gas must be allowed to leave the receiver; this process is accomplished through the pressure equalizing line (a). The pressure equalizing line makes the pressure in the receiver the same as in the compressor discharge line. The pressure in the condenser outlet is lower due to the pressure loss in the condenser. Since the condenser outlet pressure is lower than in the receiver, it is therefore necessary to mount the condenser higher than the receiver and allow for a higher liquid level in the piping between the condenser and the receiver (b).

The liquid column in the line (b) compensates for the pressure difference between the condenser outlet and the receiver.

Fig. 4 shows the liquid connection at the bottom of the receiver.

If the liquid from the condenser is connected to the top of the receiver (Fig. 5), a slightly different arrangement must be made.

The liquid line (b) from the condenser to the receiver will need to have a goose neck/liquid trap to ensure that the liquid column is actually established.

As air is heavier than ammonia gas, the air will collect in two locations in this type of installation: On top of the liquid in the receiver (x) and/or on top of the liquid in the drop leg from the condenser (y).

Connection Locations

Air purger installation in a low-pressure liquid level controlled installation

The correct locations for the air purger to be connected to the ammonia plant are:

• on top of the receiver or
• on top of the liquid in the drop leg from the condenser.

(See Fig. 6 and Fig. 7)

The air purger (5) is connected to the two purge points through solenoid valves (px and py). Note that only one solenoid should be open at any given time, otherwise the liquid column in the condenser will be short-circuited.

The air purger must have its own liquid return drop leg (c) connected in parallel with the condenser's drop legs (b).

When the purger is connected to the receiver i.e. solenoid (px) open, the liquid level in the air purger's drop leg (c) will be equal to the receiver liquid level (3); when the purger is connected to the condenser outlet i.e. solenoid (py) open, the liquid level will be equal to the liquid level in the condenser drop leg (b).

Fig. 6 Purger connections (px) & (py). Drain piping (c) must be vertical/downward slope

Alternatively, the air purger draining of liquid can be achieved effectively through an HP float valve (6) to the low pressure side (see Fig. 7).

Fig. 7 Purger connections (px) & (py). Drain piping (c) must be vertical/downward slope

Air purger installation in a high-pressure liquid level controlled installation

For systems with a high-pressure liquid level control, the air will collect in the float valve (3). (See Fig. 8).

The compressor (1) supplies high-pressure gas to the condenser (2), where it is condensed. The float valve (3) will flash any liquid back to the LP side. The air purger (5) must be connected to the float valve through a solenoid valve (pv).

The ammonia liquid condensed in the air purger must be drained through drain pipe (c) to the LP side via a float valve (6).

Fig. 8 Purger connections (pv). Drain Piping (c) must be vertical/downward slope

General

⚠️ WARNING!

Follow the installation guide strictly during Purger installation. Install the Purger unit in a location where the bottom flange level and any gas inlet connection level is above any possible ammonia liquid level.

Liquid drain piping from the purger must always have a downward slope.

Install a shut off valve close to the bottom flange entrance to enable removal of the unit and closing for high pressure ammonia gas.

Connect proper resistant piping to the purging outlet pipe and ensure the purged non-condensables are discharged into a water bath of max. 200 liter.

Connection Points

Multi-point purging

As factory default, the Danfoss IPS 8 is configured to manage up to 8 purge points. (Multi-point purging. See Fig. 10).

The actual amount of purge points connected needs to be setup in the MCX controller after power-up. The parameter in question for entering the actual number of purge point: V10, Max_PP (See Table 3).

Single point purging setup is possible (See Fig. 09 -no purge solenoid valves).

For single point purging the parameter in question for entering the actual number of purge point: V10, Max_PP must be set to 1 (See Table 3).

Both power and control wiring of the installed solenoid valves coils should take place prior to first power up.

NEVER HAVE MORE THAN 1 PURGE POINT OPEN AT A TIME.

Always close one purge valve before opening the next.

This is done by turning the purger unit power on and entering the number of actual purge points (V10, Max_PP) in the program. See section "Programming/configuration".

Fig. 9 Single point purging from receiver

Fig. 10 Multi-point purging from up to 8 purging points

See Installation guide for Danfoss floats:

• Type SV3 - Lit. No.: AN149486432996
• Type ICFD used in ICFD - Lit.No. : AN250286497620
• Refer Setup IPS 8 for Bubbler support: AN370832505987
• See Installation guide for LLS 4000 Liquid Level Switch: AN317523977313

Installation

Lifting Procedure

The Danfoss IPS 8 must be installed in accordance with locations recommended in the Connection locations and Connection points sections of this document.

The unit has a protection rating of IP55 and may be installed outside, in ambient temperature ranges from from -10 °C to 43 °C / 14 °F to 109°F). Avoid installation in direct sunlight as this may lead to excessive sunlight exposure and ambient temperatures above allowed limits. For ambient temperatures below -10 °C (14°F) the air purger must be installed in a heated and ventilated area. The unit must be installed in a non-ATEX atmosphere as the purger unit is not explosion proof.

The purger unit should be kept in an upright position at all times - from receipt to final installation.

Use all 4 lifting eyes and suitable lifting gear during installation (unit weight = 100 kg/220 lbs).

Install the unit on an even horizontal base 0.05 to 1.1 meter (2 to 43 in) above a service platform with sufficient support and allowing the purger subframe to be bolted to the support (see example in Fig. 12). Maintain recommended distances in all directions (Fig. 12) to allow fan cooling and servicing.

Always leave the unit off for at least 12 hours from finished installation to first time power up.

It is important that the support construction is level to ensure the internal liquid trap is properly filled. Angle to horizontal < 2 degrees

Fig. 11 All 4 lifting eyes must be positioned correctly, to match the actual used lifting gear

Fig. 12 Installation dimensions

Installation (continued)

Fig. 13 Ammonia connection

Fig. 14 Enclosed weld flange

1. Prepare the ammonia pipework with the weld flange according to Fig. 13 and Fig. 14. The main/drain piping should never be smaller than inner diameter Ø37 mm (1.5 in).
2. Complete the supporting structure able to carry 100 kg (221 lbs).
3. Lift the purger into position using the lifting eyes on each side of the purger's cabinet. Remove the rubber plug from the flange opening. See Fig. 13.
4. Connect the weld flange with the purger flange using the enclosed flat gasket and tighten the supplied 4 bolts diagonally to a torque of 60 Nm (44.3 ft-lb).
5. Insert 4 bolts (not supplied) through the purger frame and the support construction and tighten.
6. Perform a leak test to ensure an airtight connection.
7. In the event the purger unit needs to be dismantled please contact Danfoss for instructions.
8. Correctly install a suitable pipe/hose from the purge solenoid valve for blow-off of NC gases in accordance with local or national regulations.
9. Prepare an outside water tank with a maximum of 200 liters (53 gal.) and ensure the piping allows the purged gas to be immersed in the water.
10. Regularly check the pH level of the tank's contents.
11. The pH level should never exceed 12.6. Otherwise the water content must be renewed.
12. Dispose of concentrated waste water in accordance with to local/national regulations.

Note: Prior to replacing the water in the water tank ensure that the purger is switched off and the shut off valve at the flanged purger inlet is closed. Leave the unit in this condition for a period to allow the remaining gas in the piping to be dissolved/released.

Watch out for bubbles.

Establish a procedure for regular checking the pH level and bubble pattern. If continuous bubbles are observed in the water tank during “stand by” (Green light indicator) in normal operation, one or more of the purge solenoid valves needs repair or replacement.

Electrical Wiring

The internal wiring of the purger is done at the factory. Only the electrical wiring for the main power supply, the purge point solenoids and optional bus communication needs wiring on site.

It is highly recommended that all external cables coming from the IPS 8 to the power supply and to all purge point solenoids are protected by metallic pipes.

⚠️ WARNING! Electrical hazards. Authorized personnel only.

Fig. 15 Controller box external

Controller box cover can only be opened at key unlock and with the main switch off. Note: Authorized personel only

Fig. 16 Controller box internal

Fig. 17 Power Supply

Fig. 18 Controller MCX15B2 Inputs and Outputs

Light Indicators

Fig. 20

* The purger continuous purging until max running period (default 160 h) is reached and the purger compressor will stop

** The purger compressor stops when alarm occurs

Quick Startup

For the fastest possible system configuration after connecting all purge points to the IPS and following first power up of the IPS, follow these simple instructions:

1. Navigate from the Main Menu to Login
2. Enter password '200'.
3. Choose 'Parameters'.
4. Choose 'Unit Config'
5. Choose 'Valve Settings'
6. Enter the amount of purge solenoid valves connected to the IPS.

Navigation - built in MCX controller

(Placed at the rear of the front panel door)

After switching on the controller, a display window will momentarily show the actual software version, followed by the default main operating window shown in Fig. 26.

While in operation mode, the Up/Down arrow buttons lead the user to the status windows described in Table 01 below.

Fig. 21 - Default main window. Operating (start) mode. (Examples only)

Bubbler functionality. See Fig. 22

Configuring IPS via the HMI¹) on the MCX15B2 controller

By pressing the main menu will show up with the options below

Table 01

1) Human Machine Interface (HMI) is the interface between the IPS and the user. Here the key pad and the display on the MCX15B2

Maintenance/Service/Disposal

Table 03 Maintenance checklist - Perform once a year minimum

1. Use P&I diagram and check that all powered components are working properly
2. Check for alarms in the MCX controller
3. Fans, air filters and fins must be cleaned for dirt and dust
4. Expansion valve must be inspected and must be replaced if damaged
5. Ensure expansion valves sensor bulb has good contact with suction line
6. Replace water in water bubble bath. Check pH level frequently and replace when pH > 12.6
7. Check cover is mounted correctly and all bolts are tightened accordingly
8. Check and verify the amperage of the unit
9. Check for abnormal compressor noises in normal operating conditions (may indicate loose bolts, worn bearings or pistons)

Table 04 Procedure to isolate IPS for servicing

Disposal of the IPS 8

If an IPS 8 unit is worn out and has to be replaced, the disposal must be done in accordance with national legislation and only done by competent personnel.

Modbus RTU

Good Practice

The wiring of Modbus RTU (RS485) must be carried out in accordance with the standard ANSI/TIA/EIA-485-A-1998. Galvanic separation shall be provided for segments crossing buildings.

Common ground shall be used for all devices on the same network inclusive router, gateways etc.

All bus connections in the cables are made with twisted pair wires. The recommended cable type for this is AWG 22/0.32 mm². If used for longer distances please use a AWG 20/0.5mm² or AWG 18/0.75mm² cable. The cables characteristic impedance shall be between 100 – 1300 The capacitance between conductors shall be less than 100 pf per meter.

Note: the length of the cables influence the communication speed used. Longer cable lengths mean lower baud rate should be used. Maximum cable length allowed is 1200m.

Use a minimum 20 cm distance between 110V/230V/400V power line cables and bus cables.