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AGENDA
1. INTRODUCTION TO THE STUDY
2. MODELLING A HEAT PUMP WATER HEATER
3. OUR TOOLS AT EDF
MODELICA/DYMOLA
BUILTSYSPRO
TIL-TLK
EXPERIMENTAL FACILITIES
4. RESULTS
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HPWH STUDY INTRODUCTION
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Market study
• Analyse market trends • Bibliography research, patents
Modelling
• Detailed modelling of the basic cycle – SPLIT • Using TIL Library (Dymola/Modelica)
Experimental validation
• Validation based on experimental tests • Temperature levels, energy consumption and efficiency
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HPWH STUDY INTRODUCTION
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Market study
• Analyse market trends • Bibliography research, patents
Modelling
• Detailed modelling of the basic cycle – SPLIT • Using TIL Library (Dymola/Modelica)
Experimental validation
• Validation based on experimental tests • Temperature levels, energy consumption and efficiency
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MODEL EXPECTATIONS
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• Precision Possibility to test different heat pump cycle layouts
• Simulation speed Easily perform daily simulations with draw-off profiles
• Extensiveness A base model to be extended to all possible configurations
Model specifications
Objective: simulate one of the most occuring technology on the French market (30%)
Split type HPWH with mantle HX
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MODELLING METHODOLOGY
Split type Mantle heat exchanger air_to-water HPWH
Vapor compression
cycle
Performance sensible
to climatic conditions
Cycle configuration
Refrigerant type
Control strategy
Defrosting
Stratification
Convection when
charging
Draw-off jets
Heat losses
The Heat Pump Water Heater: « thermo-hydraulic » system
Thermo Hydraulic
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BIBLIOGRAPHY– TANK MODEL – « HYDRAULIC » PART
Precision
Speed
Fully mixed 1D nodal Pseudo 1D Zonal Pseudo CFD CFD 2D
D. Blandin
(2010), Inard et
Kenjo (2007),
Nizami,
Lightstone,
Harrison, &
Cruickshank
(2013)
Bonvini et Leva
(2012)
K. Johannes
(2005), Druck
(2006), (Zurigat,
Ghajar, & Moretti
(1988)
Nelson,
Balakrishnan &
Murthy (1997),
Steinert,
Goppert, &
Platzer, 2013,
K. Osman
(2008), Oliveski,
Krenzinger, &
Vielmo (2003),
Shah & Furbo
(2003), Arslan
(2005
K. O. Homan &
SOO (1997), K.
Osman (2008),
Oliveski,
Krenzinger, &
Vielmo (2003),
Shah & Furbo
(2003), Arslan
(2005
CFD 3D
| 8
TANK MODELLING METHODOLOGY – « HYDRAULIC » PART
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COOLING
zonal model
DRAW-OFFS
1D model
Heating
Zonal model
Mixed conditions
1D model
Temps
« Hybrid » modelling depending on conditions
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• « Machine learning » techniques based on experimental or detailed models data
• Experimental study of COP versus operating conditions
• Well suited for fast long term simulations or control strategies with low level of detail required
Empirical – black box models
• Componental and equational based models
• Some components based on empirical formulations e.g. compressors
• Well suited for comparing cycles
Semi-empirical – gray box models
• Complicated parametrization, needs good know-how
• Long time to model and slow simulation
• Well fit for individual component studies
Physics based – white box models
HPWH MODELLING TECHNIQUES – « THERMO » PART
Black Box Heat
Pump
Fine Heat Pump
model
Ch
osen
in
pu
ts
Ch
ose
n i
np
uts
CO
P
Mu
ltip
le in
pu
ts
Mu
ltip
le o
utp
uts
M
ult
iple
ou
tpu
ts
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• « Machine learning » techniques based on experimental or detailed models data
• Experimental study of COP versus operating conditions
• Well suited for fast long term simulations or control strategies with low level of detail required
Empirical – black box models
• Componental and equational based models
• Some components based on empirical formulations e.g. compressors
• Well suited for comparing cycles
Semi-empirical – gray box models
• Complicated parametrization, needs good know-how
• Long time to model and slow simulation
• Well fit for individual component studies
Physics based – white box models
HPWH MODELLING TECHNIQUES – « THERMO » PART
Black Box Heat
Pump
Fine Heat Pump
model
Ch
osen
in
pu
ts
Ch
ose
n i
np
uts
CO
P
Mu
ltip
le in
pu
ts
Mu
ltip
le o
utp
uts
M
ult
iple
ou
tpu
ts
| 11
DYMOLA
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Object Oriented
e.g. « A heat pump is composed
of a compressor and a
condensor »
Complementary interfaces
Modelling first, then simulation
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MODELICA
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Equation based
Acausal style of modelling
Inheritance
e.g. a rotary compressor is a
type of compressor
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DYMOLA/TIL
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Modelica/Dymola based library
Thermo-component library based on
objected oriented architecture
Thermal property calculation
Extensiveness
compressor or valve mass and
energy equations
Modularity
Possible to easily modify geometry
Heat exchange correlations
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EDF BUILDSYSPRO OPEN SOURCE LIBRARY**
The BuildSysPro open source library
Dymola modelling and simulation environment (compliant with OpenModelica)
Modelica language • Modelling complex multi-physic systems
Non causal equation based language
Multi-physic modelling
• Standardised programming language
Object-oriented
Non-proprietary language
equation
G*dT = Q_flow;
end ThermalConductor;
EDF’s internal
Energy and
Building’s
simulation library
Building
Geometries
HVAC systems
Climates
Scenarios
**Available in February 2016, see annex
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EXPERIMENTAL FACILITIES
Possibility to vary seasons: external temperature and
humidity
Interactive control using automated test rigs,
models/Real time simulation and online acquisition
Measuring the performance of heat pumps for heating
and hot water production
Normative experiments
Pure investigation, e.g analyzing the stratification in a
water tank according to different draw-off profiles
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Ambiant environment
External environment
Labview
Dymola
P T
0
5
10
15
20
25
30
35
40
45
50
55
60
0
500
1000
1500
2000
2500
3000
3500
4000
4500
5000
5500
6000
03
:30
:00
05
:30
:00
07
:30
:00
09
:30
:00
11
:30
:00
13
:30
:00
15
:30
:00
17
:30
:00
19
:30
:00
21
:30
:00
Température ( C)P pac (W) et Débit
(L/h)
Temps
P pac
Débit
T ballon
Tc 6(haut)Tc 7
Tc 8
Tc 9
Tc 1
Tc 2
Tc 3
Tc 4
Tc 5 (bas)
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EXPERIMENTAL INVESTIGATION
Measuring:
Temperatures along the heat pump cycle
Energy consummed and produced
Analysing performances according to
regulatory frameworks
Non standardised protocoles for investigation
and optimisation
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Extended TIL models
connected together
Specific HX models
Expansion valve models
Variable speed
compressors
Valves
Hybrid modelling
Fluid convective
movements when
heating, cooling
and defrosting
Plug flow draw-
offs
Control scenarios
Compressor & fan speed, defrosting strategies
Water draw-off profiles
Climate
External temperature and humidity
MODELLING METHODOLOGY
Split type Mantle heat exchanger HPWH
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Satisfying correlation between
experimental and modeled
temperatures in the tank
Stil some deviations
Heat loss models
Numerical precision
EXPERIMENTAL VALIDATION – TANK TEMPERATURE PROFILES
Thermal bridges with the
ambiant not taken into account
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EXPERIMENTAL VALIDATION – HEAT PUMP CYCLE 7°C(EXT.)
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Condenser Evaporator
Surface temperature vs fluid
temperature
Thermostatic Expansion Valve
hunting not taken into account
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EXPERIMENTAL VALIDATION – PERFORMANCES (TEXT)
7°C external air temperature 15°C external air temperature
Data Model Error
Qth (kWh) 3.87 3.96 2.33%
Qelec (kWh) 1.24 1.27 2.78%
COP 3.13 3.12 -0.44%
Data Model Error
Qth (kWh) 3.73 3.84 2.87%
Qelec (kWh) 1.41 1.36 -3.16%
COP 2.65 2.81 6.23%
Compressor
model error
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CONCLUDING REMARKS
Several methodologies exist for modelling Heat Pump Water Heaters
Need to take into account both system part (Energy engineering) and thermal storage (Fluid
mechanics)
Actual model still partly incomplete but interesting results
Temperature profiles when charging the tank
Temperature profiles along the HP cycle
Power consumption
Deviation in compressor model efficiencies, need for more laboratory data
This type of modelling a bit complex and too specific for one type of machine (Mantle HX)
Might not fit with the modelling objectives of the annex
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| 22 BuildSysPro | 03/02/2016
ANNEX-USING BUILDSYSPRO
BuildSysPro is going open source, and now compatible with OpenModelica!
Available February 2016! E-mail [email protected] to get the newsletter!
Open source models
Private models
Industry and measured
data