Absorption refrigerator

An absorption refrigerator configured to obtain a cold water by a circulation cycle of a regenerator, a condenser, an evaporator, and an absorber,

• the absorption refrigerator comprising:
• a plurality of temperature sensors provided in the regenerator, the condenser, the evaporator, and the absorber;
• a concentrated solution proportional valve configured to guide a concentrated solution obtained via regeneration in the regenerator to a lower part of the absorber without spraying the concentrated solution from an upper part of the absorber;
• an anti-freeze valve configured to mix a diluted solution into a refrigerant sprayed from an upper part of the evaporator;
• a storage storing an approximation function by which a second concentration of an absorption liquid is obtained, the approximation function being obtained in advance using a response surface method, based on a mass of data including:
• a plurality of first detection results obtained by each of the plurality of temperature sensors;
• and a plurality of first concentrations of the absorption liquid each corresponding to when each of the plurality of first detection results has been obtained;
• a calculator configured to apply a plurality of second detection results obtained by each of the plurality of temperature sensors to the approximation function in order to obtain the second concentration of the absorption liquid;
• and
• a controller configured to execute control in accordance with the second concentration obtained by the calculator,
• wherein the approximation function is defined as
• CS=α1×f(x1)+α2×f(x2)+α3×f(x3)+α4×f(x4)+ . . . αn×f(xn),
• where CS is a concentration of absorption, α1 to αn are numerical constants, and f(x1) to f(xn) are functions of the plurality of temperature sensors.