Integration of reversible absorption heat pumps in micro-trigeneration systems: application to an office building

The present paper investigates the integration of reversible absorption heat pumps in a novel micro-trigeneration system. Differently from traditional absorption chillers, reversible absorption heat pumps can be driven by the exhaust gas of an internal combustion engine to produce both cooling and heating, depending on the season. This technology may be particularly interesting in residential and commercial buildings with low and medium temperature emission systems. Detailed models of all the subsystems are given. Sizing and lifetime operation of the proposed system are stochastically optimized by means of a genetic algorithm coupled with Monte Carlo simulations for a case study, namely an office building located in central Italy. Energy demands are evaluated by means of a dynamic simulation, validated on real energy data. Results show that the integration of the reversible absorption heat pump provides valuable economic and energy performance. Traditional trigeneration and cogeneration systems and a separate-production system have 2%, 4% and 7% higher net present costs, respectively, also employing 4%, 9% and 11 % more primary energy. The proposed design is proven to be robust to uncertainties on the electrical, heating and cooling loads, giving a 26% reduction of the relative uncertainty range on the output net present cost and matching, in any case, the building energy demands.