Seasonal Coefficient of Performance of Air-to-Air Heat Pumps Influence on the Energy Performance of Multifamily Residential Buildings in Bulgaria

One of the most used ways to achieve nearly-zero energy buildings (nZEB) in relation to Bulgarian legislation is by the use of air-to-air heat pumps for heating. Specifically for residential and light commercial applications, split type air-to-air heat pumps are widely used. In this regard, this study aims to find how the difference between Seasonal Coefficient of Performance (SCOP) declared by the manufacturer and SCOP recalculated based on the local climate data affects the energy consumption of the buildings. The calculations were made for multifamily residential buildings with different geometry and area for all 9 climatic zones in Bulgaria. The results show that mono-split air-to-air heat pumps used for heating, can actually provide only from 17.9 to 44.9% of the required energy, which is considered as renewable, as the recalculated SCOP can be up to 25.6% lower than declared. An incensement in SCOP with 12.5% can lead to an incensement in the share of renewable energy with about 2%.