1. Heat energy from the sun Thermal characterisation of a latent heat thermal energy storage system by means of a dynamic artificial neural network Presentation for ETP PECRE Award
Dr Faisal Ghani CEng MIET
Research Associate
IMPEE, Engineering & Physical Sciences
Heriot-Watt University
6th ETP Annual Conference, University of Edinburgh, October 10th, 2017

2. Solar energy utilisation
Solar radiation commonly converted to:
Electricity (photovoltaic)
Heat (solar thermal)
Thermal energy is 58% of UK domestic energy needs
45% Space heating
18% Hot water
Energy storage a critical component within solar energy systems
Supply/demand mismatch
High thermal output needed
6th Annual ETP Conference, University of Edinburgh

3. Solar thermal systems overview
Solar thermal collectors
Fluid transfer system
Thermal Energy Storage
6th Annual ETP Conference, University of Edinburgh

4. Thermal energy storage (TES)
A number of storage technology types currently used to store solar energy
Sensible (e.g. water)
Latent (phase change materials)
Latent heat storage offers a number of technical advantages
High energy density
Overall volume reduction
Reduced heat loss (VIP)
High thermal output (~30kW)
Thermal modulation
6th Annual ETP Conference, University of Edinburgh

5. Solid/liquid phase change process
LIQUID STATE
(CHARGED)
SOLID STATE
(DISCHARGED)
Solidification process
6th Annual ETP Conference, University of Edinburgh

6. Collector performance enhancement
Melting process occurs at near constant temperature
Phenomenon can be leveraged for thermal modulation applications
Solar thermal collector performance degrades with temperature
Latent heat TES can minimise heat loss by modulating collector temperature
Reduced collector yield due
to elevated temperature
Latent heat TES advantage
6th Annual ETP Conference, University of Edinburgh

7. Collector performance enhancement
Efficiency ‘plateau’ while PCM melting
Collectors continue to charge latent heat TES
Thermal efficiency of an evacuated tube collector while charging a latent heat TES

8. TRNSYS simulation of a solar thermal system
Project challenges
System level simulation needed for:
Annual performance approximation. How much electricity do we need to purchase? Solar thermal performance gain?
System design/economic analysis. How many collectors? What size store?
Phase change process highly transient moving boundary problem requiring numerical solver ?
TRNSYS simulation of a solar thermal system

9. Development of a computationally efficient model of latent heat TES
Numerical techniques too demanding for long term simulation studies
PECRE award received from ETP to work with HSLU to develop dynamic neural network model
Step 1: Acquire training data (experimental)
Step 2: Train and modify architecture
Step 3: Test/evaluate network
Tin
Neural Network Model
Tout
Mass flow
Generic neural network architecture
6th Annual ETP Conference, University of Edinburgh

10. Neural network training data collection
Extensive experimental data collected using experimental rigs
Training data collected using apparatus located in Lucerne and Edinburgh

11. Indoor experimental apparatus
Loop 2
Loop 1
6th Annual ETP Conference, University of Edinburgh
LabVIEW software
Data acquisition system

12. Neural network testing results
Neural Network Model
Once trained testing was conducted using exp data
Excellent agreement found during charging phase
Some disparity emerges during discharge phase
Fast calculation time once network has been trained
Further data being collected
Tout
Mass flow
6th Annual ETP Conference, University of Edinburgh

13. PECRE award outcomes
A strong collaboration developed between Heriot-Watt, Sunamp, and Lucerne University of Applied Sciences
Journal paper submitted and under review
Model to be used for H2020 Project
MSc student from HSLU spending 5 months at Heriot-Watt
A unique tool developed to model phase change phenomenon in the Sunamp heat battery
Recipient of the Kerr Macgregor for Solar Innovation awarded by SSEG for research carried out in this project

14. 6th Annual ETP Conference, University of Edinburgh
How funding was spent
6th Annual ETP Conference, University of Edinburgh

15. 6th Annual ETP Conference, University of Edinburgh
Thank you
Dr Faisal Ghani CEng MIET
Research Associate
IMPEE, Engineering & Physical Sciences
Heriot-Watt University
6th Annual ETP Conference, University of Edinburgh