Techo-economic investigations of a solar driven ORC-sorption system for combined cooling, heating and power

Techo-economic investigations of a solar driven ORC-sorption system for combined cooling, heating and power

Roumpedakis, Tryfonas (TU Delft Mechanical, Maritime and Materials Engineering)

Infante Ferreira, Carlos (mentor)

Delft University of Technology

2018-10-25

The rapid growth of power systems supplied by sustainable energy sources and the attempt towards the decrease of CO₂ emissions has resulted in the increase of decentralized energy systems over the last decades. Tri-generation systems utilizing an Organic Rankine Cycle (ORC) can offer a reliable alternative towards that direction. In particular, the solar Organic Rankine Cycle can reduce down to zero the footprint of such systems. In this study, an ORC is designed such so that the rejected heat by its condenser can be used to drive a sorption heat pump. The design process of the hybrid system includes the selection of the heat transfer fluid flowing through the collectors, the working fluid and the design conditions of the ORC as well as the design conditions of the sorption heat pump. The system is evaluated for its performance in the regions of Athens, Greece and Amsterdam, Netherlands. Two configurations have been evaluated in respect with the auxiliary system; one using the existing gas boiler to provide additional heat to the sorption heat pump and one using the conventional air conditioning units to directly provide the excess of the thermal load. Moreover, the investigated scenarios include both residential as well as utility buildings in both regions. The results are compared with the ones from conventional systems, using a gas boiler and air conditioning units. Multi-objective optimization has been conducted towards the maximization of the exergy efficiency and the minimization of the payback period by determining the optimal storage tank’s volume and the solar collector’s area. The results indicated that the proposed system is operating more efficiently in Amsterdam, in which is also achieving a payback period as low as 14 years, when a gas boiler is used as the auxiliary system. The performance of the system is slightly worse in Athens, mainly due to the higher cooling loads, during which the sorption heat pump operates with low COPs.
Apart from the solar thermal cooling, a solar electric cooling system is evaluated for all the aforementioned scenarios, utilizing a PV field driving a conventional vapor compression chiller (VCC). According to the results, the PV-VCC system is a better solution in terms of the payback period, reporting payback periods as low as 6 and 9 years for Athens and Amsterdam, respectively, in the case of a residential building. In a similar way to the solar thermal cooling, for the case of utility buildings the performance is slightly worse, resulting in a payback period of approximately 10 years for Athens, while the respective value for Amsterdam is around 21 years, mainly due to the lower availability of solar radiation.

Trigeneration
Organic Rankine Cycle
Adsorption Cooling
Absorption Refrigeration
Techno-economic analysis
Genetic Algorithm
Solar cooling

http://resolver.tudelft.nl/uuid:01b282ff-3402-464e-98f4-aa664f704618

Student theses

master thesis

© 2018 Tryfonas Roumpedakis