Real-time optimal control of the CO2 heat pump system for residential use

Solutions developed

The EU is moving away from fossil fuels and paving the way for a greener future with plans for near-zero energy homes. CO2 heat pumps will play a key role in a decarbonised future of building heating systems. The EU-funded ROCOCO2HP project will work to increase the efficiency of such systems. It is developing efficient real-time optimal control (RTOC) for the CO2 heat pump as part of a building energy supply system. The project will combine scientific expertise on RTOCs with advanced experimental conditions with the CO2 heat pump for residential heating use at the host laboratory. Machine learning methods will be used to develop the non-linear system model. The findings of this project will bring new knowledge and theories to develop new RTOCs, which currently have large computational load that in turn makes them difficult to operate with real building energy systems.

Main results

The aim of this project is to develop efficient real-time optimal control (RTOC) for the carbon dioxide (CO2) heat pump as a part of a building energy supply system and validate its reliability experimentally. This is necessary to increase the system efficiency. For a high system efficiency with CO2 heat pumps for heating purpose, a low water return temperature from building heating systems is crucially important. However, this is still difficult to achieve due to well-established heating solutions and control strategies that are not suitable for CO2 heat pumps. CO2 is considered as one natural refrigerant, which has the merit of nonflammability, non-toxicity, and low price when compared with traditional refrigerants. Current well-functioning control methods are developed for heat pumps based on HFCs. Current RTOCs have the disadvantage of large computational load, which makes them difficult to operate with real building energy systems.