Study on heat transfer characteristics of straw block wall in solar greenhouse

A new type of solar greenhouse with straw block north wall was developed. The heat transfer characteristics, temperature, heat absorption, release and loss of its north wall were investigated by theoretical and experimental analyses and the economic and environmental evaluations of north walls were carried out. The thermal storage coefficient of heat storage layer, the total thermal inertia index and the total thermal resistance of the new type straw block north wall (ST) were 38.5%, 13.9% and 25.4% higher than that of porous clay block north wall (CL), respectively and the average air temperature of Chinese solar greenhouse with ST was 0.7 °C higher than that of Chinese solar greenhouse with CL on cloudy day. The temperature of heat storage layer as well as the heat absorption and release of ST were higher than that of CL. The heat loss of ST was less than that of CL. Compared to CL, the cost, energy consumption and CO2 emissions of ST were reduced 26.3%, 81.7% and 29.4%, respectively. ST had better thermal properties and could improve thermal environment of greenhouse. Besides, it was low-cost and environmentally friendly.