Performance And Applications Of Novel Solar Air Collectors For Rural Buildings

Mellapak packing has advantages of large surface area, good heat transferperformance, light weight, etc. To make better use of its advantages, Transpired SolarCollector with Punching Corrugated Plate (TSCPCP) and Mellapak Packing SolarCollector (MPSC) have been developed. Their performance, as well as their heatingperformance and energy efficiency in rural buildings, has been investigated byexperiments and simulation.First, based on analysis of the heat transfer process, mathematical models basedon energy balance equations for the TSCPCP have been developed to predict itsthermal performance in different operating mode. Mathematical model for the MPSChas also been developed to describe its Two-Dimensional heat transfer process. WithMatlab programming, iterative method for solving the models is accomplished. Thenthe models have been verified by experiments in winter. Friction factors for each solarcollector have also been analyzed with experiment results.Secondly, with validated mathematical models, the effects of structural andoperating parameters on the thermal performance of TSCPCP and MPSC have beenanalyzed. The temperature rise across collector, the thermal efficiency and the netexergy efficiency are considered as main evaluation indexes. The simulations resultsare useful in designing and optimizing the TSCPCP and MPSC for differentapplications.Compared with the Vacuum Glazed Transpired Collector with Slit-likePerforations, which was developed in prior research, the thermal efficiency ofTSCPCP is improved by5.8%and the thermal efficiency of MPSC is improved by5.8%in same conditions. TSCPCP has better thermal performance and smallerfriction. As a result, TSCPCP has great potential to promote the application.Then the TSCPCP and MPSC were applied to a typical rural building. Theheating performance under different operating modes were tested. Results show thatthe heating performance is better when the air was supplied from higher vent andreturned from lower vent. After that, the dynamic analysis model for the rural buildingwith new solar air collector has been developed and verified by the test results ofheating performance. With the dynamic analysis model, the heating performance ofthe typical rural building in winter has been simulated. Results show that the mean daily temperature can be maintained above278K in winter,9.4K higher than there isno collector. Therefore, the heating performance is significant.After adding an auxiliary heating source and a heat storage device in the dynamicanalysis model, solar fraction of the solar air heating system has been calculated. Andthe factors affecting the solar fraction have been investigated by simulation. Theoperating mode as well as the energy effects and environmental impacts of solar airheating system has also been briefly analyzed. Results show that during the heatingperiod the thermal efficiency of the TSCPCP is47.9%, and the the solar fraction ofthe system is47.3%.In summary, solar air heating systems could improve the quality of rural people’slife, provide significant energy savings and environmental benefits, and promotesustainable development for rural buildings.