Study on the thermal performance of a new type of latent heat storage unit (LHSU)

Abstract

In order to improve the utilization rate of solar energy, accelerate the heat storage rate. A new type of shell-and-tube latent heat storage unit is proposed, which is mainly composed of high endothermic film, eccentric shell-and-tube heat storage unit, fan and PCM. The unit and two greenhouses were built to study their thermal performance under four cases. The experimental results show that under the passive case (fan not run), and the maximum temperature and heat flux of LHSU sunny surface can reach 52.4 °C and −302.5 W/m2. Compared with ordinary greenhouse, the average indoor air temperature at night in the PCM greenhouse can be increased by 1–1.4 °C, and the indoor air temperature fluctuation can be reduced by 0.5–2 °C. Under the three active cases, the average indoor air temperature at night in the PCM greenhouse can be increased by 1.3–2.1 °C, 1.6–2.6 °C and 0.8–1.2 °C, respectively, the indoor air temperature fluctuation can be reduced by 1.5–2.7 °C, 1–2.6 °C and 0.7–1.9 °C, respectively. When the fan runs only at night, the unit can save 33.3% of the electric energy as compared with all-day operation, which is a better choice for further energy saving. The LHSU shows excellent energy saving performance and can effectively improve the thermal environment in greenhouse. It can also be used for energy storage in buildings.