I'm trying to model a heat pump and a water heater with a shared water tank, so heat pump (outside of the building) will heat up water in water heater (inside the building) and then this water will be used for heating and for hot water service. Similar question was asked before, but there wasn't heat pump object in OS back then so I suppose now there should will be a slightly better solution then IDF editor? What would be best objects to model such system?