The choice of appropriate generator systems to enhance the renewable energy share in buildings. A comparison between PV-assisted heat pumps and biomass boilers

Natale Arcuri,Piero Bevilacqua,Daniela Cirone,Roberto Bruno,Stefania Perrella

doi:10.1051/e3sconf/202131202014

Abstract

Low-energy buildings are generally equipped with generation systems driven by renewable sources. Regarding heating and DHW production, two choices appear appropriate: PV assisted heat pumps and biomass boilers. In this paper, by means of TRNSYS dynamic simulations, the non-renewable primary energy was determined for two buildings located in different climatic contexts by varying the PV size to consider the actual self-consumed electricity of commercial devices. Results showed that in cold climates biomass boilers are more suggested, especially in unfavourable climatic zones, whereas the COP of air-water heat pumps is strongly penalized by the outdoor temperatures and in many cases the self-consumed PV electricity does not limit the grid intervention adequately. However, in building with limited thermal energy demands and in favorable climates, suitable PV sizes make heat pumps more performant than biomass boilers. The same calculations were conducted with the quasi-steady approach, in accordance with the Italian building energy certification procedure, observing a favorable scenario in a heating plant equipped with a PV assisted heat pump because it assumes the renewable electricity entirely absorbed, while the accounting of the actual self-consumed share produces a greater demand of non-renewable energy.

Highlights

Because in recent years the issue related to the global warming caused by the use of fossil fuels have increased, it has become mandatory to expand the use of renewable energy source in the building sector
Among the several generation systems employed in residential buildings for heating and Domestic Hot Water (DHW) production purposes, electric heat pumps assisted by PV generators and biomass boilers are able to allow a rational exploitation of the renewable sources [4]
For the single-storey building, the performances of the AHWP assisted by the PV generator are always better than the biomass boiler, indicating that the magnitude of the electricity absorbed from the grid is not in such amount to be affected excessively by the penalizing conversion factor in fossil primary energy

Summary

Introduction

Because in recent years the issue related to the global warming caused by the use of fossil fuels have increased, it has become mandatory to expand the use of renewable energy source in the building sector. Currently the world housing account for 2,109,205 thousand tons of oil equivalent of consumed energy (21.2% of total energy consumption), with a correspondent amount of CO2 emission of 2033 Mton per year [1]. For this purpose, in Europe the promulgation of the Directive 28/2009/CE has promoted the use of renewable energy in the building sector to reduce the percentage of 40% on the final energy consumption that contributes for the 36% of GHG emissions [2]. It is interesting to compare these generations systems in terms of exploited renewable energy, in order to determine how they act on the limitation of the fossil primary energy and on the external environment

Methods

Results

Conclusion