Presentation on theme: "Development of EUC (End User Computing) System for the Design of HVAC (Heating, Ventilation and Air Conditioning) O.Yoshida, M.Andou Tokyo Gas Co., Ltd."— Presentation transcript:
Development of EUC (End User Computing) System for the Design of HVAC (Heating, Ventilation and Air Conditioning) O.Yoshida, M.Andou Tokyo Gas Co., Ltd.
Introduction Feature of the EUC system Wide variety of DB (data-base) Original user-subroutines Verification of DB Conclusions Contents
Introduction CFD methods have become a promising tool to optimise design parameters of HVAC by predicting thermal environment in buildings. While many advantage are expected, CFD codes still require lots of expertise and time for designers to model and predict indoor environment. Wider application of CFD has been expected, in particular, to the field of EUC that designers and even sales engineers can easily take advantage of. An EUC system for the optimal design of HVAC has been developed.
Feature of the EUC System Utilisation of PHOENICS Flexible pre-processor Powerful solver Easy VR post-processor Uniquely customised to predict indoor environment in faster, more accurate and user-friendly manners Wide variety of DB (data-base) for the analysis of HVAC Original user-subroutines Verification of DB
Wide Variety of DB (Data-base) The system incorporated DB compiled during various cases of predictions and experiments. The DB provides typical specifications of a variety of air-conditioners and buildings as a set of Q1 files. It also maintains previous Q1 and PHI files as reference, which can be readily upgraded to predict similar problems. A/C DB A/C type Building DB Q1
Original User-subroutines Along with the DB, series of practical user- subroutines have been developed using GROUND. These user-subroutines are applicable to predict ideal performance and operating conditions of air- conditioning units under desired optimal thermal environment. Optimisation of input conditions such as efflux temperature is conducted to obtain desired thermal environment in a room.
Original User-subroutines - Example Prediction of Optimal Efflux Temp. Mean temperature at the height of 0.6m for each of perimeter and interior areas needs to be 22 to achieve desired thermal environment. Office Room Type (Outside of Temp. = 0 C) Window Z=0.6m Efflux temperatures are separately controlled with reference to respective area temperature. Unit_P(Q=9m 3 /min)Unit_I 1 (Q=6) Unit_I 2 (Q=6) Perimeter (Area_P) Interior (Area_I)
Original User-subroutines - Example Algorithm Start Calculate Tm Calculate Rlx (Relax. factor) by Residual of NETSOURCE Te=Te+(Tm_end-Tm)*Rlx LSWEEP ? End Yes EARTH Solution No Tm_start=22 C, Tm_end=22 C, Te_start=40 C Temperatures. vs. Sweep No. Tm Te
Original User-subroutines - Example Temperature Distributions Plane at Z=0.6m Mean temp 22.0C Center plane of A/C units Efflux temp 30.6C Efflux temp 29.8C
Verification of DB Computation Measurement Verification Prediction accuracy of DB of the system was verified a-priori, by comparing with detailed measurements. Know-hows to generate a numerical grids have been compiled to secure practical accuracy with minimum calculation time.
Verification of DB - Example Artificial Climatic Room Schematic Diagram 3D traverse apparatus Air-Conditioning unit Model Room
Verification of DB - Example Heating Conditions Living Room Type Efflux Temp. = 46C Sink Air-Conditioning unit Outside of Temp. = 0 C Neighboring Temp. = 10 C
PHOENICS 3.2 Steady states Rectangular grids 38×32×33 = 40128cells Elliptic-staggered equation k-epsilon turbulence model Hybrid differencing schemes Boussinesq buoyancy model Verification of DB - Example Numerical Analysis Numerical Grid
Verification of DB - Example Center Plane of Air Conditioner Measured Computed
Verification of DB - Example Center Plane of Model Room Measured Computed
Verification of DB - Example Temperature Profiles
Conclusions An useful EUC system for the optimal design of HVAC has been developed using PHOENICS. The system incorporated DB for the analysis of HVAC as a set of Q1 files. Along with the DB, practical user-subroutines have been developed. Prediction accuracy of the system was verified a- priori, by comparing with detailed measurements. Computed result with incorporate DB was in good agreement with measured result.