Dynamic Simulations for the Optimum Management of an Integrated System for Air Conditioning and DHW Generation in Multifamily Buildings

The paper describes the analysis made on an integrated system for heating and DHW generation, which serves thirty families, accommodated into two blocks of apartments. The system consisting of a gas modulating condensing boiler (220 kW) used for heating and DHW, and of a heat pump (130 kW) used as integration to the boiler. A thermal solar system with evacuated tube is also considered (thirty collectors, south-west orientation and 45° slope); the energy produced is used both for heating and for DHW generation. Three storage tanks are installed: one of them is designed to integrate the thermal sources for heating, the other two work in parallel for the DHW production. The plant described is complex and each circuit (boiler, heat pump, solar field) needs to be managed according to all the other systems in an integrated way. The aim of the analysis is to figure out the optimum design for the control and the regulation system, in order to maximize the exploitation of the solar energy, to increase the load factor of the heat pump and to manage the boiler operation for achieving the highest efficiency at partial loads. The buildings and the plant have been modeled in details, to ensure a good correspondence to the real case. Dynamic simulations have been run first to analyze the management of the solar system, and subsequently to evaluate the overall efficiency of the plant, as it has been managed with different set of controls and different priorities among devices. Numerical analyses have been carried out via the commercial code TRNSYS