Authors:
László Zsolt Gergely
and
Tamás Csoknyai
Affiliation:
Budapest University of Technology and Economics, Faculty of Mechanical Engineering, Department of Building Services and Process Engineering, Műegyetem rkp. 3, Budapest 1111, Hungary
Keyword(s):
nZEB, Near zero energy buildings, Climate change, Carbon footprint, Heat pump, Total equivalent warming impact
Abstract:
Buildings account for a significant part of greenhouse gas emissions. A reasonable way of mitigation is the retrofit of the building stock, both from the perspective of the building envelope and the technical building system. However, to maximize carbon emission savings, effects of these two measures shall be observed hand in hand. This paper approaches the issue through the possible renovation of the detached houses of the Hungarian residential building stock to a nearly zero energy building (NZEB) level. Three system layouts, namely air-to-water heat pumps, air-to-air heat pumps with electric boilers and gas condensing boilers are compared in terms of greenhouse gas emissions while covering heating and domestic hot water demands. Results reflect that heat pumps offer the possibility of a remarkable reduction of carbon-dioxide emissions compared to condensing gas boilers in case of the present electricity mix of Hungary. Furthermore, it appears that after the NZEB renovation, air-to
-water heat pumps represent the best solution for detached houses. In the meanwhile, air-to-air heat pumps with electric boilers could remain eco-friendly for applications with relatively low hot water needs.
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