Design and construction of a solar heating and cooling plant

The present work deals with the design of a combined solar heating and cooling plant for an office building located in Northern Italy. An innovative system based on an absorption chiller driven by evacuated tube collectors and a dual-source reversible heat pump is presented. In summer, solar energy is used to drive the absorption chiller. In winter, solar collector field can provide hot water to the radiant ceiling circuit or, alternatively, drive the heat pump evaporator. A control strategy has been applied to manage the operation of the dual-source machine. A computer model has been developed on the TRNSYS platform for the simulation and the design optimization of the system. TRNSYS has been used also for the evaluation of the thermal loads. The simulation allowed to predict the operation of the solar heating and cooling plant on an annual basis. From the simulation results, the annual energy yield has been computed. The contribution of each primary energy source (solar radiation, fossil fuel, electricity) and the annual average efficiency of all the components (solar collectors, absorption chiller, reversible heat pump) have been evaluated. Furthermore, the simulation of an alternative heating system configuration has been carried out to explore the possibility to obtain a global efficiency increase. The plant is under construction and is expected to be operational by the first quarter of 2013.