A study on a flat-plate type of solar heat collector with an integrated heat pipe

• A new type of solar collector with a large integrated heat pipe is designed.
• An analysis of heat transfer inside new collector is presented.
• A simulation of the heat transfer model is conducted.
• The new collector can contribute to the application of more solar energy.

An improved structure of flat-plate solar heat collector applied in construction of the solar water heater system is proposed in this paper. The collector uses one large integrated wickless heat pipe instead of side-by-side separate heat pipes. High stability and leak avoidance between the water cooling side and the solar heating side are the main advantages. The present work includes three aspects. Firstly, an experiment was conducted to test thermal performance of the new collector on July 9, 2011. After a daily work from 09:00 to 16:00, the maximum collector efficiency could reach 66%, while the temperature of water of 200 kg in the storage tank increased by about 25.0 °C in the end. Secondly, a theoretical analysis on the energy balance for each component of the collector was made to understand the heat transfer process inside the collector. Thirdly, a transient heat transfer model has been developed to calculate the collector efficiency, temperatures of water, the glass cover and the absorber plate, of which the simulation results are qualitatively in agreement with the experimental data.