Paper Conference

Proceedings of BSA Conference 2017: Third Conference of IBPSA-Italy


On the Influence of Storage Size and Management on the Consumption of Air Source Heat Pumps in High Performance Buildings

Elena Bee, Alessandro Prada, Paolo Baggio

Abstract: Air-source heat pumps can be coupled with photovoltaic panels, a water storage tank and low temperature hydronic terminals (radiant floor) with the purpose of using renewable sources for domestic heating. Some kind of storage solution is required since the availability of solar energy is most of the time out of sync with the heating needs. In principle the energy storage could take place in water filled storage tanks, acid-lead batteries, and in the building envelope. The thermal capacity of the storage tank depends on the tank size and it could affect the performance of the system. Hence, the system management strategy should consider such inertia in order to correctly control the system, also by taking into account the current availability of solar energy. This work investigates whether the correct sizing of the water storage tank and its correct management can increase the energy self-consumption and, consequently, the renewable share of the primary energy used. The work analyses the behaviour of such a system configuration during the heating season in different climate conditions. Four European climates and two types of building envelopes, with different thermal capacities (timber and concrete), were considered. Results show that a control logic oriented to self-consumption can significantly reduce the energy taken from the power grid, with respect to the more typical control systems that reset the supply temperature based on the outdoor temperature. However, increasing the tank size in the range of the typical installations has only a slight effect on the percentage of self-consumed energy. In the case of the control strategy that includes outdoor temperature reset, it was found that this percentage does not change, regardless of the tank size.
Pages: 249 - 255