| 摘要 |
PROBLEM TO BE SOLVED: To provide a deep freezer for preventing decrease in control response or hunting by controlling capacity by using a control gain responsive to a secondary refrigerant flow rate from a user side. SOLUTION: An ECU 51 retrieves an assumed differential temperature Tdv from a map based on an operating state of a compressor 5 and an atmospheric temperature Ta, then calculates a deviation (differential temperature deviation)ΔTd between the temperature Tdv and an actual differential temperature Tdr (inlet side temperature Tfi - outlet side temperature Tfo), and retrieves a flow rate coefficient KF of a control gain from the map. Thereafter, the ECU 51 obtains a capacity basic increase or decrease amountΔPB from a table based on a deviation (outlet differential temperature)ΔTo between an inlet temperature gradientΔTs (i.e., change amount per unit time of the inlet side temperature Tfi) and set outlet temperature Tfos and outlet side temperature Tfo. Eventually, the ECU 51 multiplies the increase or decrease amountΔPB by the coefficient KF to calculate capacity increase or decrease amountΔP, and controls number of revolutions of a gas engine 21 based on the amountΔP.
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