Danfoss CTM 6 Data sheet

Data Sheet

CTM High pressure valve
Type CTM 6

Improves COP and lowers swept volume of the MT compressors in CO2 systems with parallel compressors

Danfoss Multi Ejector SolutionTM, consists of a
CTM 6 High Pressure valve and an AK-PC 782A
controller. This solution makes CO2 refrigeration
systems economically competitive with the
HFC systems at all ambient temperatures by
improving COP in comparison to standard
parallel compressor systems.

CO2 systems with Multi Ejector SolutionTM can
be installed in any climate delivering lower

energy consumption than i.e. R404A. It
removes the CO2 equator entirely.

CTM 6 HP is designed for CO2 systems with
parallel compression to lift a part of the gas

from MT suction and mix it with the gas coming
from the gas cooler at medium pressure level.

AI260946128833en-000601

Pressure

Danfoss
32F996.12

P

H

P

L

P

S

P

D

P

H

P

D

P

L

P

S

1

2 3

4 5

6

7

1234567

Nozzle

Throat

Exit

Mixing chamber

Diuser

Intake due to pressure dierential

Pressure increase due to reducing ow velocity

CTM High pressure valve, type CTM 6

Features

First Cost savings

• Lower cost compared to parallel compression transcritical CO2 packs due to lower swept volume of compressors.
(i.e. smaller compressors or less number of compressors).

• Reliable and robust design.

• Fully integrated solution not requiring any additional components like check valves or motorized ball valves.

• Fully serviceable - wide range of spare parts and accessories.

• Easily accessible strainer / lter for fast maintenance.

• Brings rst cost savings.

◦ High pressure valve becomes redundant
◦ Enables 15 - 35 % savings on compressor swept volume, compared to booster systems.

Fast Pay Back – Energy saving

• Improved COP, enhanced operation of parallel compressors and lower swept volume to the MT compressors ,
resulting in lower energy consumption.

• Savings for end users

• Fast payback – lower energy consumption

◦ Less compressors and higher eciency on the systems, leads to payback time of less than 2 years on avarage

globally.

• The combination of CTM 6 High Pressure and the AK-PC 782A ensure an easy setup and commissioning, robust
control of the system that ensures many years of problem free operation.

Functions

The Multi Ejector function

Figure 1: The Multi Ejector function

An ejector is a device that uses expansion energy to compress another uid. In this case with the transcritical system
there is up to 20% of the compressor work that can theoretically be recovered in the expansion.

In this case with the Multi Ejector system the work is coming from the CO2 leaving the gas cooler. The high pressure
CO2(PH) is entering the nozzle where the expansion is taking place. At the exit of the nozzle the speed is very high
and as a consequence of that the pressure is low.

This low pressure is used to drag liquid from the MT suction accumulator (PL). From there the two ows are mixed in
the mixing chamber where the pressure will be lower than at the drive inlet due to the mixing of vapour from a
higher pressure.

After the mixing the ow enters the diuser where the ow is slowed down. The shape of the diuser enables the
conversion from kinetic energy (velocity) to potential energy (pressure). After the diuser the ow is returned to the
receiver.

© Danfoss | Climate Solutions | 2021.03 AI260946128833en-000601 | 2

AK-PC 782A

AKVH

Gas cooler

Liquid
receiver

Medium temp. load

Low temp. load

Danfoss

AKS 11

MBS 8250

MBS 8250

MBS 8250

AKS 11

AKS 11

AK-CC 550A

AKS 11

AKS 11

FC 103

AKS 11

AKS 32R

AK-CC 550A

FC 103

IT MT

AKVH

AKS 11

DGS

CCMT

(ICMTS)

FC 103

MBS
8250

Multi Ejector High Pressure

LT

AKS 32R

AK-SM 8XX/
AK-SM 720/

AKS 21A

HP High Pressure (120-140 bar Max working pressure)

HP Receiver Pressure (60-90 bar Max working pressure)

LP Suction Pressure MT (35-55 bar Max working pressure)

LP Suction Pressure LT (25-30 bar Max working pressure)

CTM High pressure valve, type CTM 6

Applications

The Multi Ejector is designed to lift a part of the gas from MT suction and mix it with the gas coming from the gas
cooler at medium pressure level. Pre-compressed gas is taken from the receiver to parallel compressor which works
more eciently due to lower pressure lift required.

Figure 2: Application

© Danfoss | Climate Solutions | 2021.03 AI260946128833en-000601 | 3

0

1000

2000

3000

4000

5000

6000

7000

30

40 50

60

70 80 90 100

110 120 130

Y

X

HP 1875

HP 3875

Danfoss
32F866.10

XYInlet pressure HP side [Bar]

Mass ow HP side [kg/hr]

Refrigerant

R744 with oil

Maximum working pressure

140 bar / 2031 psi

Max. test pressure

1.43 x 140 bar / 1.43 x 2031 psi

Max. OPD

90 bar / 1305 psi (for single-voltage coil, 50 Hz)

Min. OPD

< 0.1 bar / 1.45 psi

Max. pres. dif. E and C connections

20 bar / 290 psi

Media temp. range

-10 °C – +50 °C / +14 °F – 122 °F

Ambient temp. range

-10 °C – +50 °C / +14 °F – 122 °F

Humidity

0 − 100% R.H. (0-97% R.H. non-condensation condition if IP level is below IPX5)

CTM High pressure valve, type CTM 6

High pressure lift ejectors design mass ow HP side

Figure 3: High pressure lift ejectors design mass ow HP side

Flow from the high pressure side (motive ow) for fully open ejector block as a function of temperature out of gas
cooler.

Media

Technical data

Table 1: Technical data

© Danfoss | Climate Solutions | 2021.03 AI260946128833en-000601 | 4