Danfoss TGH Series Applications And Installation Manual Download

Page: 61 / 114

61 of 114

M-AP-001-EN Rev. Q

Chapter 13.0 System Design Guidelines

In addition to the instructions detailed in the technical documentation set, this section provides basic
guidelines and requirements for the design and manufacture of systems equipped with Danfoss
Turbocor compressors.

13.1 General Requirements

1. Check for compliance with all installation, operating, commissioning, and service steps,

as outlined in the documentation set. Check for the appropriate operating envelope and

minimum unloading capacity for the intended application.

2. System components such as evaporators, condensers, valves, etc., should be properly selected

and sized for appropriate performance and compatibility with applied refrigerant.

3. The system suction and discharge piping should be properly designed and selected for

minimum pressure drop. Since the Turbocor compressor operates without lubricating oil,

conventional piping considerations that ensure oil return, such as multiple risers and traps, are

not required. In most cases, larger diameter lines will result in better compressor performance

and efficiency.

4. For improved efficiency and better control, particularly at low load / low compression ratios,

EXVs are strongly recommended. To take advantage of low pressure ratio operation to improve

low load performance and efficiency, EXV capacity should be selected accordingly. Thermal

expansion valves (TXVs) are not recommended due to the general inability of these devices

to adequately cover the operating spectrum of centrifugal compressors, particularly at low

compression ratios.

5. Take all necessary precautions to prevent any possibility of liquid floodback to the compressor.

This means consideration during the ON and OFF cycles, particularly in multiple compressor

installations. This WILL include, but is not limited to, the inclusion of a liquid line solenoid valve

and piping, evaporator and condenser arranged in a manner that prevents free drainage of

liquid to compressor.

6. The refrigeration piping system must be clean and free of all debris in accordance with

refrigeration-industry best practices Particles can damage the compressor.

7. The system control should not be designed based on pump down cycle. The system cannot be

pumped down due to the surge characteristics of centrifugal compressors.

8. Refer to "Table 13-1 Recommended Minimum Copper Tube Size" on page 61 for recommended

minimum pipe sizes.

Table 13-1 Recommended Minimum Copper Tube Size

NOTE

If steel pipe is used, the pipe must be selected to give the equivalent inside diameter to copper pipe.

Properly tapered trumpets with smooth transitions must be used to connect the compressor flanges
to the pipework.

The discharge line exit transition should not be at an angle greater than eight 8º inclusive. The suction
line length should be straight for 1.5 times the pipe diameter before entry into the compressor.

NOTE

The compressor internal safety control settings are designed to provide protection for the compressor only. Designers MUST
provide SYSTEM protection within their control design. Danfoss LLC will not be responsible for system protection other than the
compressor.

TTS300/

TGS230

TTS350/

TGS310

TTS400/

TGS390

TGS490

TTS700/

TGS520

TTH375/

TGH285

Suction