Study on hourly solar radiation design parameters in summer and winter design days

 Solar radiation design parameters for summer and winter design days are the basic parameters of building cooling and heating load calculation for HVAC, which are vital for the safe and stable operation of equipment system. In view of the problem that the traditional solar radiation design parameters based on clear-sky model in summer design day are too extreme and the solar radiation design parameters for winter design day are missing, this paper proposes a statistical method of solar radiation design parameters based on long-term solar radiation data by referring to the statistical method of outdoor design temperature of HVAC. Taking the five cities from severe cold, cold, hot summer and cold winter, hot summer and warm winter and mild zones as examples, the solar radiation design parameters proposed in this paper are compared with those based on the clear-sky model. Using these parameters, combined with the outdoor design temperature, the variation of unguaranteed time in winter and summer under different design parameters is studied. The results show that using the solar radiation design parameters proposed in this paper as the basis of building cooling and heating load, the average unguaranteed time is closer to the requirements of 50 hours in summer and 5 days in winter in relevant HVAC codes.