ADDITIONAL ENVIRONMENTAL BENEFITS AND ENVIRONMENTAL PROTECTION
Stage 2 11 170
ADDITIONAL INFORMATION Number of buildings Floor area in total ENERGY Cooling demand Cooling capacity demand Expected capacity to network Heat pumps cold Stoage tank capacity Ground source cooling Total installed cooling Heat pumps heat Heat from combined H&C
Stage 1 3 55
In addition to the cost-effective integration and optimisation with respect to the electricity price and thereby integration of fluctuating wind energy, there are several additional environmental aspects of the project for the community as well as for the consumers: • The district cooling plant for combined heating and cooling will, as shown in the picture above, be located at the waste water treatment plant and therefore it will not occupy valuable space in the urban development area. • A roof has been established to cover the water basins to prevent environmental impact of bad smell from the untreated waste water in the neighbourhood. This is why it has been possible to establish new buildings close to the plant and thereby benefit from the symbiosis between cooling and waste water. • To reduce the noise level, from the heat pumps to a low level for residential areas, special precautions will be taken, and the building will be covered in green vegetation. • The generation of heat from the treated waste water will reduce the temperature and improve the dispersion in the sea water. • There will be no visible or noisy installations on the rooftops of the cooling client’s buildings, it is planned to use the roof space of one of the buildings for a rooftop café and there will be no refrigerants and vibrations in the basements of the buildings. To conclude on the environmental aspects: this project demonstrates that smart cities have smart “backyards” in which there is a symbiosis between infrastructure for energy and environment to the benefit of the local community. ADDITIONAL TECHNICAL ASPECTS Besides the optimisation of the technical system design, there have been some interesting technical aspects under consideration, e.g.: • District cooling could be based on water technology (e.g. plastic HDPE pipes and underground concrete storage tanks) or district heating technology (steel pipes and tanks using the same water quality as for district heating). For this project we have chosen the district heating technology as it can be combined with: a steel tank (which is the best solution for storage in this project), leak detection in the preinsulated cooling pipe system, efficient insulation of the pipes (due to short distance between district heating and cooling pipes), direct connection of the consumers (to reduce temperature drop) is an option. • The supply temperature and required return temperature for comfort cooling must be 10/15 for new buildings in accordance with the Danish building code, but it has been considered to meet the request of the largest consumer to offer a slightly lower temperature for process cooling.
3.5 4.3 4.3 4.3 1.2 0 1.2 6.7 4
GWh MW MW MW MW MW MW MW GWh GWh GWh
9.2 4.6 2.5 2.0 9.2 6.7
11 39 50
Heat from waste water Total heat generation INVESTMENTS Building Ground source cooling Heat pump Waste water heat exch.
4 9 41 2 4 14 5 3 80
4 0 38 2 4 10
Mill.DKK Mill.DKK Mill.DKK Mill.DKK Mill.DKK Mill.DKK Mill.DKK Mill.DKK Mill.DKK Mill.DKK Mill.DKK Mill.DKK %
2 3 62 Chilled water tank District cooling grid Consumer connections Connection to DH network Total investmetns NPV BENEFIT, INCLUDING ENVIRONMENTAL COSTS Society of Denmark District cooling business Consumers Internal rate of return 60 17 5 13
103 52 8 41
Figure 4. Basic infomation on the technical and economical data
PARALLEL PROCESSING The planning of the project has been a challenge as the largest cooling client had a deadline for cooling. From the day that TF decided to pursue the project, we had several critical activities concurrently: • Negotiation with the clients, the heat transmission company CTR and the banks. • Updating the feasibility study for design concept, location, trench, temperatures, sales revenues, taxes and value of the heat. • Formation of a business unit for district cooling. • Application to the city council and the Energy Agency for approval in accordance with the Heat Supply Act.
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