Dynamic simulations of an adsorption chiller using low-temperature heat from Building Integrated PhotoVoltaic and Thermal system

This paper is focused on a novel thermo-economic dynamic simulation model for the energy performance analysis of Building Integrated PhotoVoltaic Thermal (BIPVT) system. The investigated BIPVT system is obtained by flat-plate PVT collectors, integrated in the building roof of a typical 3-floors office building, in order to provide Domestic Hot Water (DHW), electricity and space heating/cooling. Space heating is obtained by BIPVT collectors thermal energy supplying a radiant floor system, designed for the top building floor only. Space cooling energy is provided through an adsorption chiller, driven by the low-temperature fluid produced by the BIPVT collectors. The chilled water produced by the adsorption chiller is used to supply a fan coil unit system, installed at third floor of the building. Suitable auxiliary systems for heating and cooling energy integration and DHW production are: electric air-to-water heat pump/chiller, gas-fired condensation boiler. Dynamic simulations were carried out by the simulation model purposely developed in TRNSYS environment in order to analyse the effects due to the use of BIPVT collectors and the adsorption chiller on the building heating and cooling energy demands, on the electricity and DHW production. The obtained results are compared with those of a traditional building considered as reference system. Here, energy demand for DHW, space cooling and heating is achieved by the same auxiliary units, whereas electricity is provided by the national grid. In order to mitigate the effects of intermittency of renewable sources and obtain a virtually grid-independent system, the use of an electrical energy storage system (lead-acid batteries) is also taken into account. A suitable economic analysis is also carried out by calculating the simple payback period, with the aim to evaluate the economic feasibility of the proposed BIPVT system.