Energy saving potential pre-estimation approach for air-source heat pump usage in China based on thermodynamic irreversibility

Abstract

Building sector accounts for a substantial part of energy consumption (EC) and carbon emissions, mainly serving for building services engineering systems. As a known advanced high-efficiency equipment, air source heat pump (ASHP) has been increasingly used for indoor heating ventilation and air conditioning (HVAC) for residential and public buildings. Thus how to pre-estimate the energy saving potential (ESP) for given ASHPs under different climatic conditions is of high value for practical engineering application. In this paper, upon thermodynamic perfectibility conception, a simplified ASHP model is proposed to simulate its dynamic thermal performance according to the disparity between real equipment and the ideal reverse Carnot cycle. Moreover, a novel thermodynamic approach is proposed to pre-estimate and compare the seasoning-based ESPs of ASHP used for both heating and cooling. For illustrative examples, a typical public building is chosen, and the AHSP-ESPs are obtained and analyzed for five cities of different climate zones in China (Qiqihar, Beijing, Chengdu, Kunming, and Guangzhou). Preliminary research results show that lower/higher ambient temperatures contribute to higher heating/cooling ESPs respectively. However, the correlation between building EC and thermodynamic perfectibility is in inverse proportion. At first, building EC decreases rapidly with the increase of thermodynamic perfectibility, but as the thermal performance of ASHP gets closer to the corresponding ideal ones, the impact of thermodynamic perfectibility on building EC gradually decreases. This work is of great significance in understanding the regional applicability of ASHP and building EC, and providing application references for real ASHP usage in building sectors.