Trnsys Introduction and a little more - cvut.cztzb.fsv.cvut.cz/files/vyuka/125meb,125mec/... · Trnsys Introduction and a little more … MEB/MEC/BEPM Ing. Daniel Adamovský, Ph.D

TrnsysIntroduction and a little more …

MEB/MEC/BEPM

Ing. Daniel Adamovský, Ph.D.Department of Microenvironmental and Building Servic es

EngineeringFaculty of Civil Engineering

Czech Technical University in Prague

Outline

• Introduction of TRNSYS programme• Environment description• How to create a model?• Some examples

• Programme TRNSYS – read as transys• a TRaNsient SYstem Simulation program

125MEB/MEC/BEPM: Introduction to TRNSYS

Katedra technických zařízení budov, Fakulta stavební, ČVUT v Praze

Introduction to Trnsys

• Programme developers• Main team:

– Solar Energy Laboratory, University of Wisconsin-Madison

– http://sel.me.wisc.edu/trnsys– TESS – Thermal Energy Systems

Specialists– http://www.tess-inc.com

• Cooperators:– CSTB – Centre Scientifique et Technique du

Bâtiment– http://software.cstb.fr– TRANSSOLAR Energietechnik GmbH– http://www.transsolar.com


• Basic description• Comprehensive simulation tool suitable for modeling of

energy systems• Modular structure - a model composed of individual

components• Open "source code" - the customization options and

developing their own models (base written in Fortra n)• The possibility of linking the model with other pro grams -

Excel, Matlab, Fluent, etc.




• Field of use• Modelling of energy systems for buildings

– Solar systemsSystems with other renewables - photovoltaics, fuel c ells, cogeneration, ...

– Heat and cold storage– Ventilation systems– Links to one or more zones– Using real climatic data, traffic profiles, load zon es,




• Field of use• Modeling of control systems

– The databases includes different models of controll ers– Including the possibility of its own programming

• Analysis of energy systems– Depth analysis of the system– Finding solutions to energy system changes– Finding solutions to the problematic behavior of sy stems

• Optimization– Optimization of the proposed solutions– Sensitivity analysis on different variables and the ir changes




• What is not suitable for Trnsys• More complex models of the indoor environment (air

flow pattern, temperature field, etc.)• A more accurate description of behavior of building s

(heat transfer, thermal bridges, etc.)• Complexity and detail of model depends on partial

components used within it.




• Benefits of program• The modular structure of the model creation

– The model consists of individual components– Accompanied by a three level description

• Basic description of the search components• Detailed description of the algorithm and the physi cal nature• Summary of mathematical equations

• Clarity of the whole model• Clearly defined inputs and outputs flow between

components• Clear arrangement of model outputs - just get the re sults

I want




• Benefits of program• If we do not have a database in the "component" is

possible:– Create

• Summarize the physical and technical nature of the p roblem• Create algorithm and define the inputs and outputs• Algorithm programmed in Fortran

– Buy from a large database of other authors




Trnsys environment description

• Basic Terminology• Component model - sub-module representing specific part such

heater, heat exchanger, or any auxiliary element for output generation

• Project Assembly - an assembly of sub-modules (component models), each logically linked to the model

• Deck file - TRNSYS input file (*. dck) - file generated before calculating containing links between components and inputs into the calculation

• model file (*. TPF) - file containing information about the project• calculation protocol (*. lst) - A set of calculation, comments on

the progress of calculation, list of major errors



Mainwindow


Components list

Model space

Typical File menu

Orders forsimulation

setup

Simulation Studio – user environment for model creation



Windowfor graphicoutput


Time line – simulation lenght

Resuts on the left axeTrnexe

Results on the right axe




• Auxiliary applications• TRNbuild – multizone building

modeler

• TRNedit – dck files editor –manual editing of input files




• Component modules overview• Controllers – regulators, • Electrical –batteries, PV panels, wind turbines, aj.• Heat exchangers – different types of heat

exchangers, • HVAC – heaters, coolers, cooling towers, heat

pumps,• Hydrogen systems – fuel cells, compressors,

pressure tanks,




• Component modules overview• Hydronics – fans, pumps, flow diverters• Load and Structure – single and multi zone

modules, heat storage walls, windows• Obsolete – old modules from previous versions• Output – graphical and textual outputs to screen or

file• Physical phenomena – calculations of

thermodynamic state properties from climatic data• Solar thermal collectors – different types of solar

thermal collectors




• Component modules overview• Thermal storage – heat and cold storage,• Utility – integrators, external data loaders, calling

external programmes• Weather data reading – reading and loading of

climatic data



1. You do have a clear idea of the problem!2. You know how you want to portray it!3. You know what results you need!4. Select appropriate modules, which specify the req uired

parameters

How to create a model?


Proforma- Component description- Simplification - Link to mathematical formulation in manual

Placing a component



1. You do have a clear idea of the problem.2. You know how you want to portray it.3. Do you know what you need results.4. Select appropriate modules, which specify the req uired

parameters.Output- Search results provided by a component

Inputs and parameters:- Parameters- Inputs- (External file)

Placing a component




4. Select appropriate modules, which specify the required parameters.

5. Define the logical links between the modules.

Component modules links

Output of previous is linked to input of following module.




5. Define the logical links between the modules.6. Determine the basic properties and limits of calc ulation

Control cards- Start of simulation- End of simulation- Time step of simulation




6. Determine the basic properties and limits of calculation.7. Deck file generation and start of the simulation.


Receive some results.



7. Deck file generation and start of the simulation.8. We make adjustments to the model to obtain the

desired results



Examples


Climatic data

heater Results output

Case 1:The outside air flow rate 3000 m3/h enters a space, where is heatedwith heating rate 30 kW up to required temperature 30 °C. Isdesigned heating rate suitable for first two weeks of January? Weneed to know if this heater is able to heat outside air from outdoorair temperature to required temperature. Parameters take from theexterior climate data for locations of Prague.



Results:

Output air temperature

Outside air temperature

Energy consumption in the heater

Examples

!


Results summary:• Output of 30 kW heater heats the outdoor air flow rate 3000 m3/h

at the desired temperature of 30 °C only in the fir st 97 hours ,• The heater provides required supply air temperature when the

outdoor temperature is over 0 °C ,• If we want respect the required output temperature we need heat

output of a heater 45.5 kW,• If we require compliance with the outlet temperature and do not

want to have to increase heating output, we are to reduce the flow of air to 1980 m3/h,


Basic situation

Raised thermal output

Lower flow rate

Energy for heating 9 644 kWh 10 938 kWh 7 219 kWh

Operational costs 17 360 Kč 19 690 Kč 13 000 Kč

Examples



Case 2: Add mixing chamber• Add mixing of an outside air with a circulation air• 30 kW heater and the required supply air temperature 30°C are

the same• The amount of supply air remains at 3000 m3/h• Supply air will be mixture of 50% fresh and 50% circular air• Circulating air will have temperature of 20 °C

Climatic data

heater Results output

Mixing chamber

Examples



Results:

Air temperature after mixing

Examples






Results summary:• The heater output of 30 kW is appropriately dimensioned,• maximum thermal output at the time of the simulation is 27.4 kW at

outdoor temperature -14.2 °C and mixing temperature of 2.9 °C

Case 1 Case 2

Basic situation


Lower flow rate

Mixing

Energy for heating

9 644 kWh 10 938 kWh 7 219 kWh 7 170 kWh

Operational costs

17 360 Kč 19 690 Kč 13 000 Kč 12 900 Kč

Examples



Case 3: Heat recovery• We will add heat recovery from exhaust air,• 30 kW heater and the required supply air temperature 30°C are the

same• The amount of supply air remains at 3000 m3/h• Circulation - supplied 50% of fresh air (for recovery) and 50% circular• Heat recovery heat exchanger will have efficiency 60%

Climatic data

Heater Results output

Mixing

Heat recovery

Examples



Results:

Heat recovery

Air temperature after heat recovery

Examples

Air temperature after mixing






Examples

Results summary:• The heater output of 30 kW is now oversized,• maximum heating output in the time of the simulation is 16.9 kW

• While outside temperature is -14.2 °C, air tempera ture after heat recovery is 6.6°C and after air mixing is 13.3 °C.

• Using all thermal output of the heater we can achieve supply air temperature 43 °C

Case 1 Case 2 Case 3

Basic situation


Lower flow rate

Mixing With heat recovery

Heat recovery savings

Energy for heating

9 644 kWh 10 938 kWh 7 219 kWh 7 170 kWh 4 870 kWh 2 290 kWh

Operational costs

17 360 Kč 19 690 Kč 13 000 Kč 12 900 Kč 8 770 Kč 4 130 Kč



Thermal solar collectors

a. Determine the impact of solar collectors inclinat ionWhat is the difference in energy of the incident solar radiation on collector surface and energy produced by collectors for inclinations 10°, 25°, 45°, 60° and 90°?

b. Determine the impact of changes in the volume of hot water tank

What will be the modification of the output temperature of hot water tank after the charging period during which the solar collectors supply energy?Determine impact of changes in the volume of hot water tank to temperature in the upper output for optional volume of 200 l, 400 l, 600 l, 800 l and 1000 l .

Examples



24 h integration

Hot water daily consumption

profile

Climatic data

Solar collectorspump

regulátor

Hot water tank

Tank outlet mixing with cold water

Cold water diverter

results

results

results

Examples



slope

Daily summary of

incident energy to

collectors

Daily energy production

from collectors

Icoll Qucoll

° kJ/m2 kJ

10 5081 8437

25 4922 8319

45 4295 6855

60 3803 6118

90 2710 4627

Tank

volume

After hot water

consumptionAfter charging period

4330 4334

l h h

200 59,7 81,3

300 61,8 76,4

400 66,1 74,1

500 66,4 72,2

600 65,4 70,3

700 64 68,5

800 62,8 67,1

900 61,4 65,5

1000 60,4 64,3

a) impact of solar collectors inclination b) impact of changes in the volume of hot water tank

0

1000

2000

3000

4000

5000

6000

7000

8000

9000

10 25 45 60 90

Icoll

Qucoll

4045505560657075808590

200 300 400 500 600 700 800 900 1000

4330

4334

Examples


Computer model contra reality

Ground of this work:Experimental storage tank installed in new laboratory,Prediction of storage tank behavior and replace of repeating basic experiments,

• The computer model serves for mutual comparison between simulation and experiment,

• Suitable for preparation of more advanced experiments,

• Tank and model available also for students.



Experimental stratified heat storage

• rectangular shape made from stainless steel sheets

• glazed frontal tank wall • dimensions 600 x 700 x 1650 mm• volume 690 l

� Equipment:� pair of manifold diffuser

� 7 individual outlets on the tank height

Heat supply

Heat withdrawal

Tem

pera

ture

sen

sors




Principle of simulation model




Energy supply Energy

consumptionStratified

storage tank

Principle of simulation model

• TRNSYS model – calculate from energy balance of flows the average temperature of separate fully mixed layers – every time step

• Defined 17 temperature layers for model calculation– provide smoother view of vertical temperature

grid– 10 nodes for our tank is minimal

• Model input data are based on the data measured in the experiment.– inlet/outlet flows, inlet temperatures – surrounding temperature

• The most suitable for our storage tank is type 531 (Tess database) Type531

Model scheme




Experimental stages

Stage 1

Withdraw from the top outlet•constant position of inlets at bottom,•constant energy output•only for mutual compare of Trnsys models Type 4, 60, 531.

Stage 2

Withdraw from the outlet 6, high output•temperature of return cooled water is lower than storagetank bottom temperature,•constant energy output 3.8 kW.

Stage 3

Withdraw from the top outlet 7, variable output•temperature of return cooled water is lower than storagetank bottom temperature,•energy output changes twice during experiment.

Stage 4

Return stratification manifold•temperature of return cooled water is higher than storagetank bottom temperature,•constant energy output 0.6 kW.

Stage 5

Temporary withdraw than heating•stops at 95 minute,•start of heat up the storage tank.

Stage 1

Stage 2

Stage 3

Stage 5

Stage 4




Examples of results and discussion

� Compare for high energy output from the tank (Stage 2)

Temperature versus storage tank high

• Temperatures in water layers decrease as heat is demanded - starts at the tank bottom continuing to upper layers.

• Once cooling of water layer start, process take about 12 minutes and maximal temperature difference 9 – 12 °C to upper layer occur.

• Calculated temperatures describe uniform decrease without significant temperature differences.

• With continuing energy output temperature difference between measure and calculation increases and moves to upper layers.

• 160th minute – level 1200 mm – the highest temp. difference between measure and calculation 8.3 K

Stage 2

0

150

300

450

600

750

900

1050

1200

1350

1500

1650

22 26 30 34 38 42 46 50

Sto

rage

tank

hig

h [m

m]

Temperature [ °C]Beginning 30 min sim30 min meas 85 min sim85 min meas 130 min sim130 min meas 160 min sim160 min meas




� Compare for low energy output from the tank (Stage 3)

Temperature versus time

• starts with high energy output

• energy output from the storage tank changes:

• 57 minutes - thermal output 6 kW,

• 53 minutes decreases to 2.6 kW,

• finally last 92 minutes increases to 4.5 kW.

• 500 mm layer is influenced by high energy output – similar to stage 2

• while energy output is low results show excellent conformity

• 950 – 1400 mm layers – significant examples

Stage 3

10

15

20

25

30

35

40

45

50

55

1 16 31 46 61 76 91 106 121 136 151 166 181 196

Tem

pera

ture

[°C

]

Time [min]

1400 mm sim 1400 mm meas1250 mm sim 1250 mm meas950 mm sim 950 mm meas500 mm sim 500 mm meas

6 kW 2.6 kW 4.5 kW




Examples of results and discussion

Conclusion


Conclusion:• TRNSYS program is usable for a wide application of energy systems

simulations.• It is suitable for their design, optimization and for different case

studies.• Every model needs verification process!

• Another calculation, already verified model• Measured data (validation with reality)

• The program works with an open structure, so you can if you have the programming knowledge to create own components.

• The wide use around the world provides the opportunity to consult problems and results with other users.

• It is also possible to find published results of existing studies - useful to verify own results and to avoid possible errors already resolved.


Thank you for your attention

Daniel AdamovskýCTU in Prague, Faculty of Civil Engineering

Department of Microenvironmental and Building Services Engineering

email: [email protected]


Documents

Trnsys Introduction and a little more - cvut.cztzb.fsv.cvut.cz/files/vyuka/125meb,125mec/... · Trnsys Introduction and a little more … MEB/MEC/BEPM Ing. Daniel Adamovský, Ph.D