Potential of covering electricity needs of a flat of a MFH with
decentral compact heat pumps with PV – Simulation study for
different DHW profiles and PV field sizes
Toni Calabrese
1
, Fabian Ochs
1
, Dietmar Siegele
1
and Georgios Dermentzis
1
1
Unit for Energy Efficient Building/University of Innsbruck, Innsbruck (Austria)
Abstract
Heat pumps in combination with PV are discussed as one of the key technologies in a future sustainable energy
system. A simulation study of a flat in a multi-familiy-house (MFH) with decentral compact heat pumps and with
a photovoltaic (PV) field was performed in the CARNOT/Simulink simulation environment in order to evaluate
the potential to reduce the purchased grid electricity. PV electricity is self-consumed covering electric power
requests for heating, ventilation, appliances and Domestic Hot Water (DHW) preparation. Three different electric
power profiles for DHW preparation and two PV fields (roof, roof and façade) were analyzed.
The results of the simulations show that just a small percentage (below 26%) of electricity demand can be covered
from PV field energy. The installation of a PV field also on the façade of the flat does not reduce significantly the
purchased electricity (-11% in best of cases), while the use of daily electric storage could be evaluated to decrease
further the purchased electricity (maximum reduction of -27%). The use of annual primary energy factor instead
of monthly values overestimates the reduction of primary energy demand in all cases compared to the case without
photovoltaic system.
Keywords: MFH, compact heat pumps, deep renovation, PV self-consumption, DHW profiles
1. Motivation
One of the promising technologies investigated within IEA SHC task 56 for a future sustainable energy system is
represented by the heat pumps in combination with PV systems. Heat pumps systems represent one of the most
versatile technology and can be used for heating, cooling and Domestic Hot Water (DHW) preparation. Electricity
produced by the photovoltaic (PV) system can cover the electric demand for appliances and can be further used
for the heat pump. Such a system can significantly reduce the purchased electricity (i.e. the non-renewable primary
energy demand) of a building and the potential of this reduction is influenced, for example, by the PV sizes and
the total electric demand of the building.
A simulation study is useful to show the influence of relevant parameters of such a system (e.g. PV sizes, profile
of electric demand) on the purchased grid electricity and can give some additional information about possible
optimization of the system in order to decrease further the amount of electricity from the grid.
An annual simulation in the CARNOT/Simulink simulation environment for a flat of a typical Multi Family House
(MFH) was performed to evaluate the amount of the PV electricity self-consumed in case electric power requests
for HVAC system, appliances and DHW preparation are considered. Three different electric power profiles for
DHW preparation and two PV fields (roof, roof and façade) were analyzed.
2. Building model and simulation study
2.1 Building and PV field sizes
Fig. 1 shows the multy-family-house (MFH) with 10 flats considered for the simulation study. Detailed
information about the building model are available in [1]. The roof and the façade oriented to South-East were
assumed available for the installation of the PV field. Two different PV sizes configurations were simulated: a PV
field installed only on the roof and a PV installed on the roof and on the façade (see Tab. 1). For both PV sizes,
the total PV electricity production was correspondingly divided by 10 and this electricity was considered available
International Solar Energy Society EuroSun 2018 Conference Proceedings
© 2018. The Authors. Published by International Solar Energy Society
Selection and/or peer review under responsibility of Scientific Committee
doi:10.18086/eurosun2018.02.01 Available at http://proceedings.ises.org