SE436520B - Heat accumulator - Google Patents

Abstract

In heat exchange test conditions with a heat accumulator placed in the hot water section of a heating boiler (12, 15). The heat accumulator consists of a body made of a material displaying a high level of thermal capacity and a high fusing point, e.g. cast iron, a ceramic material etc. The heat accumulator is set up to be heated via electric energy to a considerably higher temperature than the maximum temperature of hot water section.A pipe (22) containing water etc. is arranged in a heat-transmitting connection with the rising water section/hot water section of the boiler. A circulation pump (23) with the suction side in contact with an expansion vessel controls the circulation of fluid in the heat exchange relationship with the heat accumulator with such speed that the fluid is not phase transformed.<IMAGE>

Description

azozmo-a The accumulator is characterized in that a line containing fluid in liquid phase with moderate boiling point, for example water is arranged in heat transfer connection with the riser water part / hot water part and the heat accumulator body, and that a circulation pump with the suction side in connection with an expansion vessel, preferably to atmospheric vessels , is arranged to control the circulation of fluid in heat exchange ratio with the heat accumulator at such a speed that the fluid is not phase converted. The control device of the pump preferably comprises a thermostat and / or thyristor device, which senses the temperature in the riser watering1 / hot watering1 of the boiler and / or the inlet and / or loop of the loop to resp. from the rising water part / hot water part.

The invention also provides in heat exchange conditions with a heat accumulator arranged in a boiler riser / hot water part, comprising a body of high heat capacity and melting point having materials, for example cast iron, ceramic material, etc., where the body is arranged to be heated by electrical energy to a significantly higher temperature than the maximum temperature of the rising water part / hot water part. The accumulator body comprises at least two sub-blocks, between which a plate with good thermal conductivity, for example of copper, is inserted.

On said at least one plate are suitably arranged pipes, forming part of a conduit which is in communicating connection with the riser water part / hot water part of the boiler.

The accumulator body is for example made of a ceramic material with approximately the following composition, measured in% by weight, 37% Al 2 O 3, 5% SiO 2, 17% Fe 2 O 3, 1.7% TiO 2, 38% CaO, 0.5% MgO and 0.8% alkaline substances.

In order to further illustrate the inventive concept, some embodiments of the invention will now be discussed with reference to the accompanying drawings, in which Fig. 1 schematically shows the principle of a first type of electric heating boiler. Fig. 2 shows a similar variant, Fig. 3 shows the accumulator part as a separate unit in a boiler construction generally reminiscent of that of Fig. 2, and Fig. 4 schematically shows a method of manufacturing channeled accumulator blocks.

Fig. 5 shows an accumulator body consisting of several sub-blocks, and Fig. 6 shows such a body inserted in a double-jacketed boiler.

The boiler shown by the reference numeral 10 in Fig. 1 is an electric boiler. In the known variants, the boiler type is of the type in which an electric heating cartridge 11 provides heating of the water in the hot water / radiator system 12. Pipes to and from radiators, respectively, have been denoted by 13 and 14. The domestic hot water system 15 can be heated by the surrounding system. 12 or have a separate heating cartridge (not shown). Pipes to and from the hot water tank 15 have been marked with the numbers 16 and 17.

The boiler in Fig. 1 has at its lower end a heat accumulator body 18 of a material with a high heat storage capacity, for example cast iron or ceramic material, preferably of the type containing Al 2 O 3, SiO 2, Fe 2 O 3, TiO 2, CaO, MgO and alkaline substances in the proportions 37 %, 5%, 17%, 1.7%, 38%, 0.5% and 0.8%, respectively, by weight. The effective heat capacity of a body of said ceramic material and of the order of 40x40x80 cm 3 can be estimated at a temperature of about 4000 C to 50,000 kcal. The figure corresponds well to the energy requirement for a normal villa on a normal winter day.

An electric heating coil 19 in the form of an electric cartridge is inserted in the accumulator body 18 and can, for example, provide 9kW, i.e. between 22.00 and 05.00 such a cartridge provides 63kWh of supplied energy. The connection / disconnection of the cartridge 19 is suitably controlled by a timer 20 and a thermostat.

Around the heating element 18 there is a strong insulation 21, preferably with heat-reflecting surface layer / coating. A body loop 22 is built into or inserted in the body 18, which houses a fluid, for example water. The loop 22 puts the body 18 in heat exchange relationship with the hot water part 12 when a circulation pump 23 is activated, suitably under the control of a thermostat 24 in the part 12 and / or thyristors (Fig. 6) as based on the temperature of the input to the loop 22 or the temperature difference between the input and the output controls the pump's circulation speed.

In the event that the accumulator body 18 would not have sufficient capacity, there is also an immersion heater 11 as a spare / additive unit. Both the water loop 22 and the hot water part 12 communicate with expansion vessels 25, 26. It is also possible to use the cartridge 19 for direct heating of the water in the loop 22.

The suction side of the pump 23 communicates with the expansion vessel, which is ventilated to the surroundings and contains a satisfactory amount of water. Check valves 35 are suitably arranged to prevent possible unintentional communication between the water supply in the vessel 25 and the loops in the heat accumulator body 18. 'When the correct temperature, eg 70 ”C, has been obtained in the boiler, a signal is received from the thermostat 24 and / or the thyristor and the pump '23 stops. The non-return valves 35 block water supply from the expansion vessel 25 to the heat accumulator. Remaining in the accumulator is steam of pressure corresponding to the height of the expansion vessel 25.

When the pump then receives a signal to start, there is water directly on the suction / pressure side and since the pump starts at full power and high speed, the steam is forced out immediately.

The pump is, as mentioned, suitably thyristor-controlled and returns quickly, preferably to a temperature difference controlled by input to and output from the boiler, which is thus variable within wide limits.

If the temperature of the hot water part is 70 ° C, then the temperature in the pipe loop outside the accumulator need not be higher than 80 ° C. 'I Fíg. 2 shows a boiler where the accumulator part 18 serves the hot water part 12 in principle the same way as in Fig. 1, but where the hot water part 12 and the tap water part 15 are separated via a partition 27 extending across a boiler.

Fig. 2 also shows a radiator 28 and a shunt valve 29 of known type. The arrangement in Fig. 3 differs from the previous one in that the heat accumulator body 18 is placed as a separate unit outside the actual boiler 10. Otherwise, the principle of heat exchange is the same.

Fig. 4 schematically shows how two blocks 30 and 31 - one with grooves 32, 33 formed therein corresponding to the part of the loop 22 and the electric cartridge 19 which can be placed in the body 18 - are arranged to be folded together, e.g. in a plate box 34, which is then provided with connections and insulation and then installed in the boiler or arranged as a separate unit.

Fig. 5 shows an accumulator body consisting of several sub-blocks 36, for example of the previously mentioned ceramic material. The sub-blocks are separated by plates 37, for example by copper. Pipes 38, suitably also those of copper, included in the fluid system are attached to the plates, for example by soldering, riveting. The plates 37 promote the heat transport to the fluid in the pipes 38. and compensate for any shortcomings in the contact heat transfer between adjacent blocks. The plates are also presumed to counteract the tendency to heat fatigue with concomitant cracking in the areas of the pipes 38.

In Fig. 5, heating cartridges 19 have been shown scattered in respective blocks. Other arrangements are possible, for example the elements / cartridges may be attached to the same plate as the tubes 38.

Fig. 6 shows a boiler comprising accumulator body 18 built up of three sub-blocks 36, which are separated by heat-conducting bridges forming copper plates 37. On these, pipes 38 included in the fluid circulation loop 22 are riveted, or alternatively fastened in another suitable manner.

The direction of circulation in the loop 22 is indicated by the arrows 39, 40. The circulation pump 23 has a thyristor device 41, which steplessly and within wide limits controls the speed of the pump 23 depending on a signal from a sensor 42 at the input to the loop part inside the hot water part of the boiler. The atmospherically vented expansion vessel 25 supplies the suction side of the pump with water and the steam, with pressure corresponding to the height of the expansion vessel, which may occur in the loop portion between the non-return valve 35 and the loop portion of the boiler hot water portion 12, during pump shutdown when the pump restarts.

In all embodiments, therefore, inexpensive nocturnal K-K-I energy is used and accumulates in a well-insulated storage body of compact shape and which can withstand comparatively high temperature levels.

Even if specific embodiments have been considered, it will be appreciated that modifications and alternatives are of course possible within the scope of the appended claims. The boiler does not necessarily have to be an electric boiler.

Other boiler types for waterborne heat are conceivable, also boilers of so-called combi-typ. The accumulator body can_also- be dimensioned for large boiler systems, e.g. industrial boilers, central boilers.

Claims (4)

aso2s1o-4 PATENT REQUIREMENTS 1. In heat exchange relationship with a boiler water part (12, 15) arranged in a boiler heating part, comprising a body (18) of high heat capacitance and a high melting point having material, where the body is arranged to be heated. by electrical energy to a considerably higher temperature than the maximum temperature of the riser water part) characterized in that a conduit (22) containing a liquid in liquid phase with moderate boiling point, for example water, is arranged in heat transfer connection with the riser water part and the heat accumulator body, and that a circulation pump (23) with the suction side in connection with an expansion vessel, preferably ventilated to the atmosphere, is arranged to control the circulation of fluid in heat exchange relationship with the heat accumulator at such a speed that the fluid is not phase-converted, Accumulator according to claim 1, characterized in that a control device for the pump comprises a thermostat (24) and / or thyristor device (41) which senses the temperature in the riser water part of the boiler and / or at the input to the respective outlet from the riser water part. Accumulator according to one or more of the preceding claims, characterized in that the accumulator body comprises at least two sub-blocks of ceramic material (36), between which a plate with good thermal conductivity, for example of copper, is inserted. 4. An accumulator according to claim 3, characterized in that pipes (38) are arranged on said at least one plate, included in a conduit (22) which is in communicating connection with the riser water part of the boiler. A battery according to any one of claims 4 to 5, characterized in that the battery body is made of a ceramic material having approximately the following composition, measured in Weight Å, 37% Al 2 O 3, 5 % SiO2, 17% FeO3, 1.7% TiO2, 38% CaO, 0.5% MgO and 0.8% alkaline substances.