There are plenty of other benefits, too; it doesn't charge city tax; it has both air conditioning and a heater for the rooms; it also has free Wi-Fi in every room.
还有很多别的优点：它免收城市税；房间里有空调和暖气；每个房间都有免费的无线网络。
2
In order to study the effects of refrigerant charge on the performance of a small-sized heat pump water heater, many experiments under different charge were carried out.