Standard rating conditions based on two-side multi-grade method: summary and analysis on the Chinese standards for air source heat pumps

Abstract

• Principles for determining the standard rating conditions of heat pumps are proposed. • Standard rating conditions for different ASHP systems in China are established. • Technical characters, energy savings and economic benefits of ASHPs are analyzed. Air source heat pumps (ASHPs) are widely used in various types of buildings in different regions of China. Considering the significant differences in the characteristics in heat source side and user side, providing different products for different zones is an effective strategy to promote the systematic development of the ASHP technology. To realize the goal of energy conservation, standard rating conditions are extremely important. The principles for determining the standard rating conditions based on a two-side (heat source/user side) multi-grade (different conditions) method were proposed along with the development of related standards. Therefore, the establishment of standard rating condition is introduced and summarized systematically. For heat source side, the standard rating conditions for heating were classified into four types according to the lowest ambient temperature (−25, −12, −2, 7 °C), while for cooling they were constant (35 °C). For user side, the conditions for supply air (20/27 °C for heating/ cooling), floor heating (35 °C), radiator (50 °C), fan coil unit (41/7 °C for heating/cooling), domestic hot water (55 °C), and industrial use were also determined. This study introduced the implications on ASHP by different standard rating conditions, especially the technical requirements, which indicated the necessity of providing different system cycles and compressors. The energy savings and economic benefits were also evaluated. The primary energy saving rate reached 15.3% and 41.6% compared with coal heating and conventional ASHP respectively by using low ambient temperature ASHP. The results showed that these standards have been satisfactorily developed.