Modelica-Based Heat Pump Model for Transient and Steady-State Simulation Using Low-GWP Refrigerants Paper 2264

Transcription

1 Modelica-Based Heat Pump Model for Transient and Steady-State Simulation Using Low-GWP Refrigerants Paper 2264 Jiazhen Ling, Abdullah Alabdulkarem, Hongtao Qiao, Vikrant Aute Reinhard Radermacher 15 th International Refrigeration And Air Conditioning Conference at Purdue, July 14-17, 2014, Purdue, Indiana

2 Objectives Contents Modelica Component Library Heat Pump System Schematic and Test Matrix System Modeling, Simulation Results and Validation Summary 2

3 3 OBJECTIVES

4 Objectives Characterize transient performance of heat pump system 1 Models are capable of evaluating various low GWP refrigerants such as D2Y60 and R32 Models are validated using experimental data Facilitates dynamic control strategy development 1 : A. Alabdulkarem, Y. Hwang, R. Radermacher, System Drop-In Tests of Refrigerants R-32, D2Y-60, and L-41a in Air Source Heat Pump, Test Report #20, AHRI 4

5 MODELICA COMPONENT LIBRARY 5

6 Modelica Component Library Flow network Air, brine & refrigerant flow network Compressors Fixed-speed compressor model Variable-speed compressor model Economized scroll compressor model Valves Generic orifice model Adiabatic capillary tube model Check valve model Reversing valve model TXV model Accessories Accumulator model Receiver model Flash tank model 6 Heat Exchangers Tube fin heat exchanger model Micro-channel heat exchanger model Fluid-to-refrigerant plate heat exchanger model Moving boundary heat exchanger model Mixture two-phase flow model w/o interfacial exchange Fluid-to-fluid internal heat exchanger model Pipe model Frosting model Defrosting model Fan model Qiao, H., Aute, V., Radermacher, R., Transient modeling of a flash tank vapor injection heat pump system. Part I model development. International Journal of Refrigeration. (accepted)

7 SYSTEM SCHEMATIC AND TEST MATRIX 7

8 Heat Pump System Schematic Test Indoor Outdoor Operation DB WB DB WB Extended condition 46.1 C Steady state A 19.4 C 35.0 C Steady state B 26.7 C 27.8 C NA Steady state C Steady state <=13.9 C 27.8 C D Cyclic

9 SYSTEM MODELING, SIMULATION RESULTS AND VALIDATION 9

10 Heat Exchanger Model Finite volume analysis Quasi-steady state on the air side Frosting and defrosting modeling capabilities 3 control volumes Refrigerant stream Tube and the associated fins Air stream Staggered grid scheme Air flow direction Fin Tube Control volume 10

11 Compressor Model Curve-fitted model based on the performance map,, 60,,, Heat transfer inside the shell and from shell to environment is taken into account

12 Mass balance Energy balance Accumulator Model Leaving enthalpy Case 1: no phase separation d V m m dt acc acc in out dh dp V m h h m h h dt dt acc acc acc acc in in acc out out acc Case 2: phase separation h out h acc m in, h in Vapor m out, h out h if H H d Hliq Hout h h h h if H d H H dout h if 0 H H f liq out out out g g f out out liq out g liq out H liq Liquid H out H acc 12

13 Example of Simulation Results Q cond. = kw Q cond,exp = kw Error = 5.5% Power = 3.33 kw Power exp = 3.43 kw Error = 2.9% Q evap. = 8.90 kw Q evap,exp = 8.94 kw Error = 0.4% R32, Extreme Condition

14 R32 Steady-State Validation R32 Test condition A Test condition B Test condition C Sim. Exp. Error Sim. Exp. Error Sim. Exp. Error Q evap (kw) % % % Q cond (kw) % % % COP (comp. power only) % % % P discharge (Bar) % % % P suction (Bar) % % % 14

15 D2Y60 Steady-State Validation D2Y60 Test condition A Extended condition Sim. Exp. Error Sim. Exp. Error Q evap (kw) % % Compressor Input (kw) % % COP (compressor % % power only) P discharge (Bar) % % P suction (Bar) % % Test condition B Test condition C Sim. Exp. Error Sim. Exp. Error Q evap (kw) % % Compressor Input (kw) % % COP (compressor % % power only) P discharge (Bar) % % P suction (Bar) % % 15

16 D2Y60 Cyclic Simulation Results Compressor on Compressor off Compressor on

17 D2Y60 Cycle Cooling Capacity Comparison Accumulated cooling capacity deviation: 7% 17

18 D2Y60 Cycle Pressures Comparison

19 D2Y60 Cycle Charge Migration

20 R32 Cycle Cooling Capacity Comparison 20 Accumulated cooling capacity deviation: 3.4%

21 R32 Cycle Pressure Comparison

22 22 SUMMARY

23 Summary Developed cycle model according to inhouse HP test facility Validated the model using R32 and D2Y60 under both steady-state and transient conditions Models predicted performance matching experimental data 23

24 24 Thank You