Development of EUC (End User Computing) System for the Design of HVAC (Heating, Ventilation and Air...
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Transcript of Development of EUC (End User Computing) System for the Design of HVAC (Heating, Ventilation and Air...
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 optim
ise 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 SystemUtilisation 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 DBQ1 Q1
Original User-subroutines• Along with the DB, series of practical user-subroutine
s 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 - ExamplePrediction 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=9m3/min) Unit_I1(Q=6) Unit_I2(Q=6)
Perimeter (Area_P) Interior (Area_I)
Original User-subroutines - Example
AlgorithmStart
Calculate Tm
Calculate Rlx (Relax. factor) by Residual of NETSOURCE
Te=Te+(Tm_end-Tm)*Rlx
LSWEEP ?
EndYes
EARTH Solution
No
Tm_start=22 C, Tm_end=22 C, Te_start=40 C
Temperatures. vs. Sweep No.
Tm
Te
10
20
30
40
50
60
0 200 400 600 800 1000 1200 1400 1600 1800
Efflux Temp.of Unit_P
Mean Temp.of Area_P
Efflux Temp.of Unit_I
Mean Temp.of Area_I
Tem
pe
ratu
re(C
)
Sweep Number
Original User-subroutines - Example
Temperature Distributions
Plane at Z=0.6m
Mean temp 22.0C 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
0 10 20 30 40 500.0
0.5
1.0
1.5
2.0ComputedMeasured
Temperature(C)
Hei
gh
t(m
)
Center of Room X=2.17m Y=1.735m
●
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.