Overview
This thesis was completed as part of my Master of Engineering in Energy Systems at University College Dublin. The research focused on developing specialised simulation models to optimise the performance of low energy plant alternatives for the National Gallery of Ireland refurbishment project.
Context
The National Gallery of Ireland was undergoing major refurbishment works including an extensive upgrade to the mechanical and electrical systems. The proposed design, provided by BDP (Building Design Partnership), incorporated several low energy plant alternatives: a combined heat and power (CHP) unit, a heat recovery chiller, and ice banks. However, the existing building simulation models did not account for the combined performance and interaction of these plant items.
Working closely with the BDP engineering team throughout this research ultimately led to me interviewing with them for a graduate role, which I accepted upon completing my degree.
Approach
I developed a specialised model in TRNSYS (Transient System Simulation Tool) to analyse the combined performance of these systems. Each low energy plant alternative was analysed in turn to determine optimal control philosophies for minimising energy costs and CO₂ emissions. The overall compatibility of the plant items was also examined.
Key Findings
- CHP Unit: Provided the greatest savings when maximising power output during on-peak electrical periods and modulating output during off-peak periods to ensure full heat utilisation.
- Ice Banks: Optimal performance achieved through prolonged charging over the entire available period and chiller priority discharge control.
- Heat Recovery Chiller: Operating as an air source heat pump was only economical during off-peak electrical periods given existing energy prices, though CO₂ savings were achievable at all times.
- System Integration: The plant items had both positive and negative effects on each other, but the addition of each item provided significant energy cost or CO₂ savings.
Conclusion
The net present value analysis after ten years showed that including all three plant items resulted in the greatest value for money. Beyond the financial benefits, the combination contributed to CO₂ emission reductions and smoothing of electrical demand on the national grid, both goals of national interest.