Modularity in water-water heat pumps with integrated latent heat storage for energy-efficient residential applications

Description

Modular heat pump technologies emerge as a promising solution for the phase-out of conventional technologies (e.g. gas-fired boilers) in residential applications. Herein, the modularity stands for a series of refrigeration circuits coupled together to satisfy the overall demand for a wide range of apartments with a perfectly tailored number of refrigeration cycles built up in heat pump (HP) modules. The modular approach allows for keeping the refrigerant charge of R290 per circuit below the critical limit for a safe operation in a residential environment. The work aims to address the optimal hydronic scheme with a control strategy for a set of water-to-water HPs to meet the overall energy demand (i.e. space heating and cooling, domestic hot water) in Modelica/Dymola. The simulation results showed that for heating operation, during the daylight (and especially in cold climates), the serial configuration outperforms the parallel one since it can reach higher water temperatures; thus the setpoint indoor temperatures are met for a longer time. The parallel configuration, due to the higher mass flow reaching the latent heat storage, is capable to maintain it sufficiently charged over time. For cooling operation, the results highlighted the possibility of using such heat pumps in a modular approach to satisfy the space cooling demand effectively.
The work considers a conventional heating system with a boiler running on natural gas and a mechanical cooler as a reference system. Results indicate that such a solution outperforms reference systems and achieve annual CO2 savings up to appx. 2 tons/a for each single apartment compared to its reference counterpart.

Period	25 Sept 2024
Event title	BauSIM 2024
Event type	Conference
Conference number	10
Location	Vienna, AustriaShow on map
Degree of Recognition	International