Experimental investigation on the solid desiccant heat pump in different switchover periods

Equipped with the desiccant-coated heat exchanger (DCHE), the solid desiccant heat pump (SDHP) is a promising air handling method for its high energy efficiency and dehumidification capacity. Previous studies mostly use a short switchover period to obtain the high dehumidification rate, however, the short switchover period also aggravates energy loss. To reveal the effect of the switchover period, especially a longer one, an SDHP system is constructed and studied in this paper. Results indicate that the condensation temperature keeps increasing in the short switchover period, while it tends to be constant at first and then rises in longer switchover periods. Besides, the long switchover period leads to the high superheat and subcooled degree and causes extra energy loss. Based on this discovery, the working strategies of the throttle valve and compressor are optimized. The energy loss can be reduced by 41.9 % and the COP is improved by 11 % without reduction of cooling capacity. With the optimized working strategies, the research on SDHP in different switchover periods (3–10 min) and environments (30–33 °C, 50–70%RH) is conducted. In every condition, an optimal switchover period exists to achieve the highest COP. As the humidity increases, a longer switchover period is recommended.