Stadtwerke Gießen is renewing the heating and cooling supply for Sparkasse Gießen in Johannesstraße, which is expected to be completed by the end of 2020. The modernisation will bring a significant increase in efficiency.
The dismantling of old heat generators in the region has rarely been more spectacular: in May, a 90-tonne crane hoisted the two redundant combined heat and power (CHP) units from the roof of Sparkasse Giessen in Johannesstrasse in the middle of the city. The operation was an important milestone in the complete modernisation of the bank's heating and cooling supply. The contract for this was awarded to Stadtwerke Gießen (SWG).
The aim of the modernisation is to produce heating and cooling much more efficiently than before. To this end, the savings bank and SWG have concluded a special contract. It stipulates that the cooling in particular will not only be produced for the Sparkasse, but also for other customers. "The new chillers will feed into a network that is also used by the city administration, the municipal theatre, the congress hall and the multiplex cinema," explains Thomas Wagner, Head of Business Customer Sales at SWG. The CHP unit, which SWG has already replaced as part of the project, would also be somewhat too large for the savings bank. Nevertheless, its installation makes sense. Excess heat - if it is generated - is fed into the district heating network.
The partnership, which is set to run for another 15 years, is of course also worthwhile for the Sparkasse: it receives the discounted electricity generated by the CHP. "We have been working with SWG for many years and are very satisfied. That's why we also awarded this major project to SWG without hesitation," adds Peter Wolf, Chairman of the Management Board of Sparkasse Gießen.
Everything new
SWG will continue to use the energy centre on the roof of the Sparkasse building. However, only the room and the peak load boiler located in it. The new CHP unit has already been installed next to it. The two chillers will follow in the cooler months. Then it will be even more exciting and even more spectacular than in spring. This is because SWG will need a 250-tonne crane to lift the refrigeration units, which weigh around seven tonnes, onto the roof of the energy centre. "The problem is not so much the weight itself, but the distance from the crane's location to the roof," explains Christian Spratte, project manager in the heat supply department at SWG. The crane actually has to bridge almost 50 metres with its boom. This is precisely why the very large version is necessary. And this is what makes the endeavour a real logistical challenge.
When the project is completed at the end of 2020, SWG will not only have replaced the heating and cooling generators, but also the entire pipework and distribution systems. The energy experts from Lahnstrasse are also installing a new buffer storage tank. They are using this to operate the resulting cooling network efficiently.
Many small improvements, combined with the latest technology, ultimately ensure that considerably less primary energy is used in relation to the useful energy generated. However, it is only possible to estimate exactly how high the energy savings will be. "The system is simply too complex and has too many variables to provide truly reliable, concrete figures. Even attempting to do so would be dubious. Especially because we feed cooling and heating into external grids," explains Michél Sennhenn. He is responsible for the project in SWG Sales. "But it is clear that the new systems work much more efficiently and that we can reduce the CO2 emissions of the overall system considerably."