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NIST Standard Reference Database 49

CYCLE_D: NIST Vapor Compression Cycle Design Program: Version 5.1

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Customers who purchased version 5.0 can receive version 5.1 for free. Please email to data@nist.gov with SRD order number for version 5.0.

Price: $200.00 online

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CYCLE_D simulates vapor compression refrigeration cycles that use single-compound refrigerants or refrigerant blends. The model can simulate a basic subcritical or transcritical refrigeration cycle, both with or without a liquid-line/suction-line heat exchanger. In addition, the model can simulate a subcritical two-stage economizer cycle, a subcritical three-stage economizer cycle, and a subcritical two-stage compression cycle with intercooling.

CYCLE_D includes 70 single-compound refrigerants and 97 predefined blends. Single-compound fluids can be combined to form blends of up to five components. Computationally, the program is fully compatible with the NIST Reference Fluid Thermodynamic and Transport Properties - REFPROP, Version 9.1.



The basic subcritical or transcritical system simulated by CYCLE_D consists of a compressor, a discharge line, a condenser for the subcritical cycle (a gas cooler for the transcritical cycle), an expansion device, an evaporator, a compressor suction line, and an optional liquid-line/suction-line heat exchanger. The other subcritical cycles may contain a second compressor, and one or two economizers or an intercooler (but do not include the liquid-line/suction-line heat exchanger).

The user of the program has to specify the refrigerant and provide operational input data for the above hardware components, except the expansion device, which is modeled as being isenthalpic. The user can also specify the power requirements of the indoor fan, outdoor fan, and control unit of the system.

Compared to the Version 4.0, CYCLE_D Versions 5.0 and 5.1 include five functional upgrades: (1) allows for saturation pressure inputs for both the evaporator and the condenser, (2) allows the user to impose refrigerant pressure drops in the evaporator and in the condenser, (3) allows the user to specify the compressor isentropic efficiency for each stage for multi-stage cycles, (4) allows the user to assign waste heat from motor inefficiency losses to either the evaporator load, suction refrigerant vapor, or condenser load, and (5) allows for the optimization of the intermediate pressures for a three-stage economizer cycle. In addition, Version 5.1 uses the representation of thermodynamic properties based on NIST Standard Reference Database 23 - NIST Reference Fluid Thermodynamic and Transport Properties: REFPROP Version 9.1 (versus Version 9.0 in CYCLE_D Version 5.0 and Version 8.0 in CYCLE_D Version 4.0.)

Please click here to view the PDF version of User's Guide.

System Requirements: Free space for complete installation: 8 MB. CYCLE_D is designed to run on any personal computer (PC) capable of Microsoft® Windows® 7, 8, 10 or XP with Service Pack 3.

The installation module requires .NET Framework 2.0 Service Pack 2 (or later version), which can be downloaded from the Microsoft website if not present on the user's PC.

or more information please contact:

Standard Reference Data Program
National Institute of Standards and Technology 100 Bureau Dr., Stop 8550
(301) 975-2200 (VOICE) / (301) 975-4553 (FAX) / Contact Us


The scientific contact for the database is:

Piotr A. Domanski
National Institute of Standards and Technology 100 Bureau Drive, Stop 8631
Gaithersburg, MD 20899-8631
301 975 5877 piotr.domanski@nist.gov

Keywords: air conditioning; alternative refrigerant; ammonia; chemical engineering; vapor compression cycle; compressor; cooling equipment; equation of state; mechanical engineering; refrigerants; refrigeration.