Operation and energy-saving effects of solar - natural gas household heating system

Abstract: In a solar-natural gas combination heating system, hot water tanks from the household solar hot-water system were connected in a series, with the heating circuit of the household hanging wall stove. Return water from the hanging wall stove was warmed by the solar thermal-storage water. To detect the operational and energy conversion of the combined heating system, experimental research was carried out in allusion to a user in Hohhot. The data were collected by solar irradiance monitoring instruments and a solar hot-water thermal performance tester. The hanging wall stove output 55℃ heating water and its efficiency was 93%. The solar collector of the household solar hot-water system was a U-tubular, all-glass evacuated and CPC reflector board. The daylight area for the solar collector was 3m2. Results show that household solar hot-water system is a powerful supplement to the household hanging wall stove heating system. Per unit time natural gas consumption decreased when the household solar hot-water system made a contribution to heating. Daily average solar radiation was 12.8MJ/m2 and the daily average initial temperature of the solar thermal-storage water was 41.9℃ in the heating season. Total energy gains of the household solar hot-water system were 3652.7MJ. At the same time, 13.7MJ of energy were lost to the air by U-tubular. For most of the combined heating time, the return water of heating had a higher temperature than the solar thermal-storage water, which was warmed by the heating water returned by the hanging wall stove. The heat exchange in this process was stored in the hot water tank for participation in heating in the future. There was no energy loss in the heat exchange, but the heat was produced by the hanging wall stove, which led to energy loss in the energy conversion. Unexpectedly, there were 145.6MJ energy loss caused by the alliance of household solar heat-water system and the household hanging wall stove. Effective energy levels of the household solar hot-water system for heating are 3493.4MJ, which are worth saving natural gas 101m3. Through practical operation of this combined heating system, it can be seen that the household solar hot-water system is a strong assistant to the household hanging wall stove when natural gas is in short or no supply and the combined heating system runs stably. We suggest the household hanging wall stove users who have a household solar hot-water system utilize the solar-natural gas combined heating system. However, it is not economic to the independent wall hanging stove-heating users who have no solar hot-water system to invest in it.