On the basis of finite volume method

numerical simulation on steady-state thermal performance of flat-plate solar collector with double glass covers were carried out.The physical model of the collector was established and the validation of this model and its grid independence test were both performed.Moreover

through comparison with the conventional plat heat collector

the effects of ambient temperature

inlet water temperature

solar radiate intensity and lower glass cover position on thermal performance of the heat collector were investigated.The results show that

when the ambient temperature is below 18 ℃

the collector with double glass covers shows advantages.When the ambient temperature is-10 ℃

the instantaneous efficiency of the flat-plate solar collector with double glass covers is 0.26 higher than that of the conventional plat heat collector.The increase of the inlet water temperature and the solar radiate intensity both result in an increase in the temperature inside the collector

which enhances the insulation effect of the double glass covers.When the inlet water temperature is 50 ℃

the instantaneous efficiency difference between the flat-plate solar collector with double glass covers and the conventional one increases to 0.27.When the lower glass cover is located 18 mm over the absorber plate and the solar radiate intensity is1 000 W/m2

the instantaneous efficiency of the flat-plate solar collector with double glass covers can reach up to 0.678.