Best practices and recent advances in hydronic radiant cooling systems – Part II: Simulation, control, and integration

There is an ever-increasing interest in radiant cooling systems (RCSs) due to their energy-saving potential and improved indoor thermal environment in modern buildings. In this part of the review, an overview of established practices and recent efforts in modeling, simulation, operation, control, and integration of RCSs is provided. Models and simulation tools are essential for reliable planning and design of RCSs due to the thermal inertia of activated slabs/panels. However, an increasing number of steady-state computational models of the indoor environment was highlighted, which does not match the highly dynamic nature of radiant systems, especially for thermally activated building systems (TABS). Integrated models of indoor environment and cooling systems, with high accuracy and moderate computational costs, are still lacking. Advanced control strategies, such as model predictive control, were found to reduce energy consumption by up to 44% while maintaining the space at favorable conditions. A major share of saved energy is due to intermittent operation of circulation pumps. Proposed strategies are often compared to conventional rule-based controllers. However, more studies are required to benchmark those predictive and adaptive controls. An emerging research direction on the integration of renewable energy resources was highlighted, yet coupling dynamics need to be further addressed in the literature, especially for solar power-driven systems. To boost this research direction, it is recommended to take advantage of previous studies on the integration of renewable energy systems with conventional cooling systems.