Patent ID: 7565926

Claim:
A heat exchange method which uses a heat exchange unit for exchanging heat between first and second media to adjust a temperature of the first medium, said method comprising: (a) a detection step of detecting temperatures of the first and second media to enter the heat exchange unit; and (b) an adjustment step of adjusting a flow rate of the second medium based on the temperatures of the first and second media detected in said detection step, wherein said adjustment step comprises: (i) a target heat quantity calculation step of calculating a target heat quantity based on a target temperature of the first medium and the temperature of the first medium detected in said detection step; (ii) a first temperature difference calculation step of calculating a first temperature difference based on the target temperature and the temperature of the second medium detected in said detection step; (iii) a setting step of setting a provisional target flow rate of the second medium; (iv) a second temperature difference calculation step of calculating a second temperature difference based on the target heat quantity, the provisional target flow rate, and the temperatures of the first and second media detected in said detection step; (v) an average temperature difference calculation step of calculating one of a logarithmic average temperature difference and an average temperature difference at the heat exchange unit based on the first and second temperature differences; (vi) a heat exchange quantity calculation step of calculating a heat exchange quantity at the heat exchange unit based on one of the logarithmic average temperature difference and the average temperature difference and a heat exchange gain of the heat exchange unit; and (vii) a determination step of determining a target flow rate of the second medium based on a result of a comparison between the heat exchange quantity and the target heat quantity.