SOLAR THERMAL HEAT PIPE COLLECTOR SYSTEMS

D. Ristoiu1, C. Cosma1, T. Ristoiu2, O. Cozar3, D. Cenan2

1University Babes-Bolyai, Faculty of Environmental Science, Str. M. Kogalniceanu nr.4, 400084, tel. +4 0264 405316, Cluj-Napoca, Romania, 
2Technical University, Cluj-Napoca, Str. Constantin Daicoviciu nr 15, 400020 Cluj- Napoca, Romania tel. +4 0264 401 200,  Romania
3University Babes-Bolyai, Faculty of Physics, Str. M. Kogalniceanu nr.1, 400084, tel. +4 0264 405300, Cluj-Napoca, Romania, 

In recent years the growth rate of the use of solar collectors for domestic hot water heating, has shown that solar heating systems are both mature and technically reliable. Every day, world-wide thousands of systems demonstrate the possibilities of this undisputedly ecologically harmless energy source. Motivated by the confirmed success of these hot-water systems, more and more house builders are also considering using solar energy for space heating. This can be realised in one or two family houses, in multifamily houses combined with medium or large (seasonal) storage and also in villages in combination with district heating networks mainly powered by biomass or fossil fuels supported by large central solar plants mainly in summer time for domestic hot water preparation.
Solar water heating could make an important contribution to a households energy use as typically around half of a monthly domestic electricity account goes towards heating costs. A correctly installed solar water heater saves between 50% and 80% of your water heating bill and can be an effective companion to an existing water heating system. A solar water heater is most valuable as part of an efficient system otherwise much of its output and savings are wasted, consequently many householders also consider installing more energy efficient appliances and measures as part of installing a solar water system. A carefully designed and installed system ensures your household of a quality service from the system. In addition modern systems are reliable and need no more maintenance than a typical household water heating system.
Heat pipe exchangers offer a unique, compactly sized method of energy recovery that requires no external energy. A heat pipe is a passive heat transfer device with an extremely high effective thermal conductivity. Its twophase heat transfer mechanism results in heat transfer capabilities from one hundred to several thousand times that of an equivalent piece of copper. Heat pipe operation is completely passive and continuous. Since there are no moving parts to fail, a heat pipe is very reliable. This paper explains the basic design and operation of the thermal heat pipe collector systems and provides a method to determine the feasibility of a heat pipe heat sink design.