BACKGROUND OF THIS INVENTION

Until now there are problems to establish the heat accumulator effectively and permanently, with the existing heat exchange systems for instance heating boiler construction used in the heat exchange system, because it become cracked and destructed within a short period after completion.

Besides the cost of energy is becoming increased and studies for energy saving motivates to use cheap night electric energy at daytime and to turn it is practical use. Method to transfer cheap night electric energy into heat and store it to use in daytime was studied to file it as PCT applications, of which No. 0183327 discloses a contact heat accumulator arrangement and No. 0183328 discloses a heat accumulator arranged in heat exchange relation with a cooling/heating machine

In the prior art EPO patent application No. 83903597.9 is related to more effective heat accumulator in combination with the heat accumulator and heat exchanger. Such a known method makes use for instance of a water tank as storage vessel. In order to provide an energy storage capacity at a resonable level, bulky space and cost demanding constructions are required. Other known constructions are also based on complex arrangements which are expensive and constitute doubtful solutions to the problem of using cheap night energy. In the prior art the heat accumulator is connected in series to a heating system and large volum heat transfer pipes of chamber type are arranged in a heat

accumulator block of a high capacity.

This pipes are dimensioned such that vapour is formed in the chambers. When there is no heat transfer from the block. When restarting the heat transfer, the vapour is pressed out sucessively from each chamber. Such operation involves control problems.

SUMMARY OF THE INVENTION

In order to reduce the risk of uncontrolled vapour distribution there is suggested a condensor in the outlet from the accumulator and/or separate vapour outfeed from individual chambers. Another system requires an auxiliary condensor arrangement comprising a water system including an expansion vessel, a pump and a control means for the pump sensing the temperature in the system heated by the heat accumulator.

This invention is related to the pipes to press out steam, vaporized state of water, as a heat transfer material in such heat accumulator. Other material besides water can be used as heat transfer material, for the brief explanation of this invention, water is used as a heat transfer material below. The heat accumulator comprises a body of a material having a high heat capacity and a high melting point, for instance cast iron, ceramics, etc., and the body is arranged for being heated by electric energy to a temperature considerably higher than the maximum temperature of the heat exchanger from 10 P.m. to 6 a.m. The heat accumulator body heated by electric energy is covered with insulator (adiabator) to keep its heat in it.

In the daytime most electric energy is used in factory and business area from 9 a.m. to 6 p.m. and the heat stored in the heat accumulator makes hot water provided for home. The heat accumulator can be heated by electric energy during lunch break from 12 a.m. to 1 p.m. like cheap night electric energy.

A conduit containing a fluid in a liquid phase of a relatively low boiling point, for instance water, is arranged in heat transferring communication with the heat exchanger and the heat accumulator body.

A circulation pump is arranged in the piping for water transport between the accumulator body and the heat exchanger and on its suction side has a piping in communication with an expansion vessel so as to stand the maximum pressure, and a temperature sensing means is so arranged that the pump stops when the heat exchanger reaches a predetermined temperature, thereby keeping in the piping in the accumulator body dry vapour in a state of moderate pressure generated in the expansion vessel or temperature sensing can also be a room thermostat which is used when the accumulator is connected to a floor heating system.

Consequently, when the pump receives a start signal from said temperature sensing means for renewed heat transfer between the heat accumulator body and the heat exchanger, vapour is instantly let out to fill the piping. The heat exchanger may have an expansion vessel of either open type or closed loop type to stand the expansion pressure. The control device of the pump preferably employs a thermostat or a thyristor device for sensing the temperature of the water in the heat exchanger system or at the inlet or outlet from the heat exchanger.

The heat accumulator body is for instance manufactured from a ceramics material having approximately the following composition, comprising by weight 90X MgO, 4% SΪ02, 4% CaO and different kinds of oxides. The heat accumulator consists of ceramics material and heating wires are placed in holes in the ceramics material and connected in series to an electric supply source. The heat pipes are arranged in the heat accumulator body. The heat accumulator body is covered with thick insulator and is coated with heat reflective layor or reflector film for better heat conservation. Pipes are inserted into the heat accumulator to pass water therein and exchange heat between the heat accumulator body and pipe system. The circulation speed of circulation pumps is controlled by thermostat or thyristor in the system in association with the temperature of inlet pipe or the temperature difference between input and output.

BRIEF DESCRPTION OF THE DRAWING

This invention will become more fully understood from the detailed disscription given hereinbelow and the accompanying drawings which are given by way of illustration only, and wherein;

Fig. 1 is a chematic drawing of heat accumulator according to this invention. Fig. 2 is a sectional view of pipe apparatus according to this invention. Fig. 3 (A) (B) (C) are schematic drawings of embodiment of pipe in heat accumulator according to this invention.

* The numerals in the drawings indicate the following elements.

Numeral 1 indicates a heat accumulator, numeral 2 indicates an electric heating wire, numeral 3 and 8 indicate a pipe, numeral 4 indicate an adiabvatic material, numerals 5 and 6 indicate circulation pumps, numeral 18 represents a steam condensing apparatus, numeral 7 represents an assistant heat accumulating tank, numeral 30 represents a hot water tank, numeral numeral 16 represents a radiator, numeral 20 represents a control unit, numeral 24 represents thermostat, numeral 14 represents heat accumulating, numeral 25 represents an expension chamber, numeral 17 represents a connector, and numeral 19 represents a cold water valve.

DETAILED DESCRIPTION OF THIS INVENTION

Fig. 1 llustrates a schematic drawing of the heat exchange system including a heat accumulator and a heat exchanger in accordance with this invention. The heat accumulating matrial in heat accumulator (1) is heated by electric heating wire (2) connected to control unit (20) controlling the power suppy. The heat accumulator (1) can be heated to 600° C even sometimes to 850° C and the heat is stored in a heat accumulating material, such as cast iron, or ceramics.

For use of the stored heat, the water in pipe (3) in the heat accumulator (1) circulates by the operation of circulation pumps (5) (6) and the heat accumulated in heat accumulator (1) is delivered through steam condensing apparatus (18) to hot water tank (30). Cold water filled in the hot water tank

(30) through inlet (34) is heated by the hot water in pipe (3) with the help of fan (9) and supplied from outlet (35) to the kitchen or bathroom and other uses. The pipe (3) may also be connected to radiator (16) so as to heat a bedroom or livingroom. As explained in the above, expansion chamber (25) may be installed in a closed type in pipe (3) or saperately in an open type on the outside.

The circulation pumps (5) (6) supply low-temperatured water to the heat accumulator (1). The control unit (20) which also controls night electric supply constitutes a heat accumulating system (14) with heat accumulator 1. In case of being heated beyond the capacity of heat accumulator (1) or upward of 850° C, the excess heat is stored in an auxiliary heat accumulating tank 7 which may be provided in plurality to increase the capacity of heat accumulation. Heat accumulators (1) can be connected serially or parallelly in accordance with the size of house or heating space to control the capacity of heat storing.

In this invention, pipe (3) in the heat accumulator (1) can be heated upto 600° C even sometimes up 850° C and is formed in the shape of " ι ( |ι " to keep steam long on top of the heat accumulator (1) .

Consequently the steam can absorb high-temperatured heat from the vincinity of the pipe and the temperature of the water in the pipe (3) is controlled to correspond to that of the water in hot water tank and in heat accumulator (1) and to keep the predetermined temperature by the operation of thermostat (24) (33). As the temperature of water lowers, the speed of circulation pump (6) is accelarated to maintain the predetermined temperature,

for example 70° C, of the water.

According to this invention a high heat leading capability powder 3b can

^• be filled in the hole (3a) between pipe (3) and storage material (1) to provide for the expansion of the heat accumulator in accordance with temperature change. The high heat leading capability powder (3b) is made for example of copper, cement powder or silicon carbide, which compensate the difference of the temperature expansion constant between defferent materials according to the temperature change of pipe to protect an accident to crack or break of the heat accumulator (1) in advance in the heat exchange system in accordance with this invention, a fluid in this pipe (3) may be the heat transfer material of liquid state which has high boiling point and low boiling point.

This invention also provides pipe connector (17) (17') between inlet and outlet of the heat accumulator (1) which is made of ceramics, or porselain to portect the heat loss and electric leakage by means of connecter of non-leading electricity material betweren pipe (3) and circulation pump (5) in heat accu lating system (14).

The embodiment of installation according to this invention are shown in Fig. 3 (A)(B)(C), to install pipes (3) verticallty or horizontally in system which can be used in accordance with the place and status effectively. The system (14) according to this invention can be used to connect to cooling machine (16) or heaing machine (16) in heat accumulator (1). Several systems can be adjusted serially or parallelly in accordance with the size of the building or house.

Pipe apparatus of heat accumulator (1) according to this invention can be used permanently without crack or break in account of the difference of expansion-contraction constant between different materials in accordance with the high temperature. Also this apparatus installed vertically or horizontally can be used as a economics and high heat efficiency system suitable to the conditions or environments.