Speaker
Description
The new energy plant at the University of Stavanger is an advanced campus energy hub for high-efficiency heating and cooling, using ammonia heat pumps connected to geothermal boreholes and dry coolers within an integrated low-temperature energy infrastructure. Although such systems are designed to improve energy efficiency and operational flexibility, there is often a gap between design intent and operational follow-up. This paper addresses this gap by assessing one control strategy in the UiS energy plant.
Three dry coolers were installed for peak-load heat rejection during summer operation, but are also used to support the thermal balance of a constrained borehole field. One operating mode is to use the dry coolers as the sole heat source for the heat pumps when ambient conditions and heating demand allow it. The purpose is to reduce heat extraction from the boreholes when ambient air can provide sufficient heat. However, the operators soon observed unstable operation, with frequent switching between modes, leading to the dry-cooler-only heat source mode was temporarily taken out of operation.
The work compares operational data with a simple physics-based model of dry cooler performance to evaluate whether this mode has a practical role. The results assess available heat contribution and the interaction between ambient temperature, heating demand, and borehole field operation.
The study provides insight into the advantages and limitations of dry coolers as an ambient heat source in large-scale heat pump systems and highlights the importance of operational follow-up when developing control strategies for hybrid geothermal and air-source energy systems.
| Topic Area | Smart Energy Storage, Integration and Utilization |
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