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- Lundin, S.E., et al.
(författare)
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Solvärme och säsongslagring med borrhål i berg och llågtemperatur för bostadsområdet Anneberg, Danderyd : Förprojektering
- 1998
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- In the planning of a new housing area for 100 dwellings, a pre-design has been made for a solar heating plant. The aim of designing a layout, is to compare the solar system with more conventional heating systems. Developers and contractors are invited for turn-key tenders of the different systems. The single family houses, apartments and service premises in two storey, will have a total floor area of 9000 m{sup 2}. The heating demand is estimated to 1100 MWh/year (120 kWh/m{sup 2}) and the power to 450 kW. A new concept system is designed with low temperatures in all essential parts, but heat pumps are not needed. (1) Flat plate solar collectors, mean temperature 60 deg C; (2) Seasonal bore hole heat store in rock, temperature level 30-45 deg C; (3) Heat distribution network, working temperature 20-80 deg C; (4) Floor heating coils, temperature 25-32 deg C; (5) Peak electrical heaters in houses; (6) Solar DHW and auxiliary individual electrical final heaters. The system has only one general heat fluid with a mixture of water and glycol flowing through solar collectors, store, culverts and the floor heating coils. In all operation modes the heat carrier has the same flow direction and even act as a`buffer volume`. The bedrock consist of outcrops of granite and the GWL is at a depth of 4 m below the ground. In a 120 m investigation bore hole, a so called`Response test` is made in situ of the rock and the duct system. The obtained thermal results are: Conductivity{lambda}= 4.1 W/m,K, Capacity C 0.6 kWh/K, m{sup 3}, Resistance total of PEM-tubes and rock mass R= 0.02 K/(W/m). The investment cost have been calculated to 5.4 mil SEK ({approx} 0.7 mil USD) excl. culvert, floor heating system, DHW tanks/heaters. The annual capital and running costs are 0.73 mil SEK (0.1 mil USD), calculated with an interest rate of 6% over 25 years (0.078). The total system heating cost will be 0.68 SEK/kWh (0.1 USD/kWh). With received EU- and -governmental subsides up to 2.0 mil SEK the heating costs drop to 0.54 SEK/kWh (0.07 USD/kWh). Solar energy is by that means cost-effective to conventional alternatives as district heating, bio-fuel block centrals, ground heat pumps or 100% electrical heating. The solar heating project seems in all respects possible to carry through - but the final decision is taken of the market response
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