Daikin R22, Refrigerant Piping Design Manual, Page: 2 / 78

AG 31-011 • REFRIGERANT PIPING DESIGN 2 www.DaikinApplied.com
The information contained within this guide represents the opinions and suggestions of Daikin Applied. Equipment, and the application of the equipment and system
suggestions are offered by Daikin Applied as suggestions and guidelines only, and Daikin Applied does not assume responsibility for the performance of any system as a
result of these suggestions. The system engineer is responsible for system design and performance.
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
Audience . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
Using This Guide. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
How to Determine Equivalent Length . . . . . . . . . . 3
Refrigerant Piping . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Refrigerant Piping Design Check List . . . . . . . . . . . . . 5
Product Information . . . . . . . . . . . . . . . . . . . . . . . . . 5
Jobsite Information . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Typical Refrigerant Piping Layouts . . . . . . . . . . . . . . 6
Piping Design Basics . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Pressure Drop and Temperature Change . . . . . . . . 9
Liquid Lines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Suction Lines. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Suction Line Piping Details . . . . . . . . . . . . . . . . . . 11
Discharge Lines . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Discharge Line Piping Details . . . . . . . . . . . . . . . . 14
Multiple Refrigeration Circuits . . . . . . . . . . . . . . . . . . 15
Sizing Refrigerant Lines . . . . . . . . . . . . . . . . . . . . . . 16
Refrigerant Capacity Tables . . . . . . . . . . . . . . . . . . . 16
Equivalent Length for Refrigerant Lines . . . . . . . . . . 17
How to Determine Equivalent Length . . . . . . . . . 17
How to Size Liquid Lines . . . . . . . . . . . . . . . . . . 18
Refrigerant Oil . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
Suction Line Sizing . . . . . . . . . . . . . . . . . . . . . . . . . . 20
Oil Return in Suction and Discharge Risers . . . . . . . 21
How to Size Suction Lines . . . . . . . . . . . . . . . . 23
How to Size a Suction Line Double Riser . . . . 25
Discharge Line Sizing . . . . . . . . . . . . . . . . . . . . . . . . 26
How to Size a Discharge Line. . . . . . . . . . . . . . . 26
Thermal Expansion Valves . . . . . . . . . . . . . . . . . . . . 28
Hot Gas Bypass . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
Hot Gas Bypass Line Sizing . . . . . . . . . . . . . . . . . 30
Hot Gas Bypass Valves. . . . . . . . . . . . . . . . . . . . . . . 30
How to Size a Hot Gas Bypass Line. . . . . . . . . . 32
Installation Details . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
Pump Down. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
Piping Insulation . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
Refrigerant Line Installation . . . . . . . . . . . . . . . . . . . 33
Low Ambient Operation . . . . . . . . . . . . . . . . . . . . . . . 34
Fan Cycling and Fan Speed Control . . . . . . . . . . . . 34
Condenser Flood Back Design . . . . . . . . . . . . . . . . . 34
Safety and the Environment . . . . . . . . . . . . . . . . . . . 36
Appendix 1 — Glossary . . . . . . . . . . . . . . . . . . . . . . . 37
Appendix 2 – Refrigerant Piping Tables
(Inch/Pound) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40
Appendix 3 – Refrigerant Piping Tables (SI) . . . . . . 59