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Vapor Cycle and Heat Pump🔗

A vapor cycle consists of at least one evaporator and a condenser plus compressors and expansion devices. A refrigerant flows through a closed loop system, where it changes between liquid and vapor phases at different pressure levels to absorb and reject heat at the temperature levels of the cooled or heated component. Drawing the state of the fluid in a pressure-specific enthalpy diagram shows a counter-clockwise state transition for a refrigeration vapor cycle, or clockwise for a heat pump.

During early design, a vapor cycle can be run in steady-state using Vapor Cycle Library. This is convenient for the study of performance and supervisory control of a system, as transients are less relevant in this product development phase. Some components have sizing functionality, which allows imposing design intent (e.g., heat exchanger design point heat transfer flow rate) instead of all component geometry parameters.

Note

All component models in Vapor Cycle Library don't support the steady-state simulation mode; refer to this description for details.

In any design phase, the transient behavior of a vapor cycle can also be simulated using Vapor Cycle Library. This can be critical during the early and detailed design, for instance for the development of automatic controls and integration activities (e.g., hardware-in-the-loop in verification and validation).

Heat exchanger models are structured by the geometric design:

  • fin and tube
  • plate heat exchanger

and fluids:

  • refrigerant-to-air
  • refrigerant-to-refrigerant.

Two types of heat exchanger models are available.

  1. Medium fidelity models based on generic geometry parameterization such as heat transfer area and hydraulic diameter are contained in Vapor Cycle Library.
  2. Highly detailed models that are parameterized via geometry parameters of fins, flat tubes, plate fins, tubes and so on are contined in Heat Exchanger Library. These also support various discretization options and inhomogeneous impingement boundary conditions.

Models of electrical drives, for instance for compressors, can be found in the Electrification Library. See the Propulsion and Power application for more details.