System Description

Подпись: Fig. 1. The demonstration site in Borlange, with (left) water jacketed stove, (middle) technical and store units in a bathroom under the stairs, and (right) view of the 10 m2 collector array on the roof.

The REBUS system concept consists of two compact units; the solar store unit and the technical unit that contain the hydraulic components including the pellet boiler and an auxiliary store for the hot water production (see also figure 2). Both units are built in cabinets of 60cm x 60cm (width, depth) which are the standard dimensions for kitchen and bathroom units like refrigerators and washing machines. The system uses a 12 kW water jacketed pellet stove with an internal water volume of 20 litre. The stove heats an auxiliary standby store and the upper part of the solar buffer store. The solar store comprises a water volume of 360 litre and has, due to high efficient vacuum insulation at the hottest parts of the store, a low UA-value of about 1.8 W/K. The solar system can provide heat to both stores. Instead of the separate water jacketed pellet stove, an integrated or separate pellet boiler can be used without any changes in the hydraulic layout. The system is equipped with one central controller with a specifically developed software for the control for all system components except the pellet stove. A detailed description can be found in [2].

In July 2006 a prototype of the REBUS system was installed in a single family house in Borlange/Sweden that had earlier been heated with electrical radiators. In the main house these heaters were replaced by water based radiators. First the two units were installed without a pellet heater. In the middle of October 2006 the water jacketed pellet stove was added in the living room where a chimney was accessible. Up until this point a 6 kW electrical heater in the 80 litre standby store in the technical unit was used as the auxiliary heater. The stove has an integrated 38 kg pellet store which is fed manually by the owners (see Figure 1, left). The technical and store units were installed in a small room that earlier was used as a second bath room. (see Figure 1, middle). The collector field of 10 m2 (Figure 1, right) consists of four modules of Svesol premium AR with a standard rated output of 465 kWh in Stockholm at constant 50°C. It was placed on the main roof facing 40°E with a slope of 40°.