Master's Thesis Michael Mans


Energy and economical comparison of future scenarios for buildings and district heating grid of Campus Melaten

The subject of this masterthesis is an economic and energy efficiency study of various scenarios for
the future for the campus Melaten of RWTH Aachen University. The aim is to give insights about
future energy needs of the campus and to identify energy efficiency potential. This aim is achieved
by considering the heat demand of existing buildings and their supply by a district heating grid and
its energy plants. Essentially there are two ways to save energy in this case. On the one hand, the
heat demand can be reduced by retrofit measures. On the other hand the primary energy demand
can be reduced by a more efficient heat production plant.
The retrofit measures are investigatedwith the help of dynamic simulations of the existing buildings
and evaluated by their economical costs. It turns out that the achievable savings through the retrofit
measures are not sufficient enough to achieve a good economical investment at the current energy
prices. Renewing the heat production unit is done by three block heat and power plants, each with
1,977MWthermal power and a downstreamboiler. In first place the technical feasibility of this realisation,
in relation to the existing district heating grid, is tested. Afterwards this method is assessed
to its economic and energy efficieny. In this case the realisation of this method is a very worthwhile
investment and it leads to save 26,30% of the primary energy demand.
In a final step the combination of the two ways is examined for the best possible primary energy
saving and its best economic investment. For this purpose the new block heat and power plants
are realised in addition to the retrofit of some existing buildings. It turns out that the achieved net
present value is positive after a period of 10 years. Accordingly the relatively poor investment of
the building retrofit is compensated by the good investment of the new heat production units. The
achieved primary energy savings are 32,02% and only possible by the combination of the two investigated