04205nas|a2200373 i 4500 20260818223131.0 290200s1999 th uu m rtt 00| a1eng d .b11777667 AIT Thesis no.ET-99-20 Pisit Pannigul A study of temperature and flow distribution in a natural circulation solar water heating system Bangkok : Asian Institute of Technology, 1999 123 leaves Thesis ; no. ET-99-20 A thesis submitted in partial fulfillment of the requirements for the degree of Master of Engineering. School of Environment Resources and Development Thesis (M.Sc.) - Asian Institute of Technology, 1999 Domestic solar water heaters (DSWH) with horizontal tank are commonly available in Thailand. The aim of this study was to conduct experimental studies on two commercial systems, to study the temperature and flow distribution in the collector, riser, piping and storage tank in order to compare their performances and identify parameters influencing the performance of the system. Two different DSWH systems were used in the study. In the old DSWH system, two methods of connecting the return pipe to storage tank (at the top and at the middle) were used, while in the new system, the return pipe was connected to the middle. For all three modes (of the two systems), temperature of absorber plate, water and flow rate through riser and connecting pipe were experimental measured. Twelve days of experimentation was done (four for each mode of connection), while for analysis, days with similar radiation were used. The temperature and flow distribution curves have been drawn for each of the modes and comparative studies with theory done. The model for temperature distribution based on energy balance was compared to experimental data, while Close's model was used to compare the flow rate. The experimental observations indicate that the water flow rate through each riser at a given time can be considered to be fairly uniform (of about 0.8 to 2.0 cm3 /sec). The riser and connecting pipe dimensions seem to influence the flow rate through the risers. Lower flow rate in a riser is found to increase the water temperature. The model of Close was found to predict the flow rate within reasonable limits for horizontal storage tanks as well. The temperature of absorber plate across risers follows closely the theoretical prediction, except where the flow rate is not uniform. Experiments indicate that it takes about 5 hours for all water in storage tank to circulate through the new system. This leads to an increase in the water temperature at the storage tank bottom much more than if the circulation takes more time. In the old system, the time taken for the water to circulate was much longer (about 8 hours) and this reduced the highest temperature attained and the efficiency. This is also influenced by the pipe dimensions and location of the pipe at the storage tank. The results of the study indicates that uniform flow through the riser and the appropriate dimensions of pipe (connecting and risers) influence strongly the rate of water circulation and therefore the efficiency of heating water. Solar water heaters Kumar, Sivanappan, Chairperson Pham, Hoang Luong, Examination committee Surapong Chiraratananon, Examination Committee Asian Institute of Technology. Thesis ; no. ET-99-20 Full-Text http://203.159.5.9/ait-thesis/detail.php?q=B12783 .b11777667 mnait u 240421 0 000229 m a u 2 mnait mnarc 22 40 Barcode : 30050120731947 CREATED : 2014-03-02 RECORD # : i12754717 LPATRON : 0 LCHKIN : - # RENEWALS : 0 # OVERDUE : 0 IUSE3 : 0 TOT CHKOUT : 0 TOT RENEW : 0 Barcode : 30050120365464 CREATED : 2016-06-15 RECORD # : i13037109 LPATRON : 0 LCHKIN : - # RENEWALS : 0 # OVERDUE : 0 IUSE3 : 0 TOT CHKOUT : 0 TOT RENEW : 0 114923 114923 0 0 0 0 MAIN MAIN mnait 2026-08-18 50.00 0 AIT Thesis no.ET-99-20 30050120731947 2026-08-18 22:31:31 3 2026-08-18 22 0 0 0 0 MAIN MAIN mnarc 2026-08-18 0 AIT Thesis no.ET-99-20 30050120365464 2026-08-18 22:31:31 2026-08-18 40