Temperature control of the heater has been set at 33°C in the first experiment. Temperature in the up-flow pipe was greater than in the tank-accumulator during the first hour. When these temperatures became equal, the rising of temperature in tank-accumulator stopped at the level of 25°C (see Fig. 4). The duration of the cycles became longer (see Fig. 5), and heat accumulation was discontinued (see Fig. 6). Greater duration of cycles occurs when water in the accumulator is heated up completely and the heater fills only thermal losses. The difference in temperature between the descending pipe and the up-flow pipe was about 7°C. Only 0.6 liters of water flowed through heat exchanger during one cycle independently of heat source temperature.

The behavior of process was similar for other temperatures of the heater (see Fig. 7).

Time, h:mm

2.

Conclusion

Testing of laboratory model demonstrated stable operation and the heat flow depended on the capacity of the heater. This model of the circulating pump starts to act autonomously when the temperature difference between the descending pipe and the up-flow pipe exceeds 7 degrees. The proposed device can be used when heat has to transfer from a heat user source which is located below it, and can especially be used with a solar installation instead of an electrical circulating pump. The testing of a device which is integrated with a solar installation is currently underway.

References

[1] .Davidson J. H., Walker H. A., Lof G. O. G.. Experimental Study of a Self — Pumping Boiling Collector Solar Hot Water System. Journal of Solar Energy Engineering, 1989; 111 (3): 211 — 218.

[2] .Dobrianski Jury, Fieducik Jolanta Urz^dzenie do przekazywania ciepla w kierunku przeciwnym do konwekcji naturalnej. Patent PL 195490 B1 F24D 9/00 F03G 7/06

[3] .Dobriansky Y „Reverse thermosiphon’Undustrial heat engineering, Vol. 28, №6, 2006. — str. 44 — 48 (in Russian).

[4] .Dobriansky Yuriy. „Reverse thermosiphon”. IV International conference “Problems of Industrial Heat Engineering” Kiev, Ukraina 26 — 30 September, 2005. s 144.

[5] . Roberts C. C., Warrenville Jr. A Review of Heat Pipe Liquid Delivery Concepts/ Advances in heat pipe technology. London: Pergamon Press, Oxford, 1982: 693 — 702.

[6] . Walker H. A., Davidson J. H. Second — Law Analysis of a Two-Phase Self-Pumping Solar Water Heater. Journal of Solar Energy Engineering, 1992: 188 — 190.

[7] . Walker H. A., Davidson J. H.. Analysis and Simulation of a Two-Phase Self-Pumping Water Heater. Journal of Solar Energy Engineering, 1990 Vol. 112: 153 — 160.