Patent ID: 8199313

Claim:
A temperature regulating apparatus that includes a heat exchanger and regulates a temperature of a first medium by performing heat exchange between the first medium and a second medium via the heat exchanger, the apparatus comprising: a first temperature sensor configured to detect a temperature of the first medium flowing out from a primary side outlet of the heat exchanger; a second temperature sensor configured to detect a temperature of the first medium flowing into a primary side inlet of the heat exchanger; a third temperature sensor configured to detect a temperature of the second medium flowing into a secondary side inlet of the heat exchanger; a fourth temperature sensor configured to detect a temperature of the second medium flowing out from a secondary side outlet of the heat exchanger; a regulating operation unit configured to generate a flow rate regulating signal so that the temperature of the first medium flowing out from the primary side outlet becomes equal to a target temperature; a control valve configured to regulate a flow rate of the second medium based on the flow rate regulating signal; and a correcting operation unit configured (a) to calculate, based on temperatures detected by the first temperature sensor, the second temperature sensor, the third temperature sensor, and the fourth temperature sensor, a heat exchange amount of the heat exchanger, a logarithmic mean temperature difference or an average temperature in the heat exchanger, and the flow rate of the second medium, (b) to calculate an overall heat transfer coefficient of the heat exchanger based on the calculated heat exchange amount and either the calculated logarithmic mean temperature difference or the calculated average temperature, z-rate (c) to obtain a ratio (ΔG) of a change (Q 2 -Q′ 2 ) in the heat exchange amount to a change (ΔF 2 ) in the flow rate of the second medium based on the calculated flow rate (F 2 ) of the second medium and the calculated overall heat transfer coefficient (K), and (d) to output the obtained ratio to the regulating operation unit to correct a gain of the regulating operation unit.