Patent ID: 8087258

Claim:
An air conditioner, comprising: a refrigerating cycle comprising a compressor, at least one high pressure-side heat exchanger, a throttle device corresponding to each high pressure-side heat exchanger, and at least one low pressure-side heat exchanger, which are connected by pipes, for circulating high-temperature and high-pressure refrigerant within the high pressure-side heat exchanger and low temperature and low pressure refrigerant within the low pressure-side heat exchanger; a fluid sending section for making fluid flow through an outside of the high pressure-side heat exchanger to cause heat exchange between the refrigerant within the high pressure-side heat exchanger and the fluid; a high-pressure refrigerant temperature detecting section for detecting condensation temperature within the high pressure-side heat exchanger; a high pressure-side heat exchanger outlet side refrigerant temperature detecting section for detecting temperature of the refrigerant on an outlet side of the high pressure-side heat exchanger; a fluid temperature detecting section for detecting the temperature of the fluid flowing through the outside of the high pressure-side heat exchanger; a control section for controlling the refrigerating cycle based on each detected value detected by each detecting section; a computing section for computing a condenser liquid phase area ratio A L which is a ratio of a heat transfer area of a liquid phase portion of the refrigerant to a heat transfer area within the high pressure-side heat exchanger based on each detected value detected by each detecting section; and a judging section judging a refrigerant filled state within the refrigerating cycle based on a comparison of the condenser liquid phase area ratio A L computed by the computing section with a predetermined threshold value; wherein the condenser liquid phase area ratio A L is calculated by the following expression; A L ⁢ % = ∑ k = 1 n ⁢ ( ⁢ Q j ⁡ ( k ) × [ - Ln ⁡ ( 1 - SC ( k ) dTc ( k ) ) × dTc ( k ) × Cpr ( k ) Δ ⁢ ⁢ Hcon ( k ) ] ) ∑ k = 1 n ⁢ ⁢ Q j ⁡ ( k ) wherein k is a number of the high pressure-side heat exchanger, n is a total number of high pressure-side heat exchangers, Qj(k) is a heat exchange capacity of each high pressure-side heat exchanger, SC(k) is a value obtained by subtracting the outlet temperature from a condensation temperature of the high pressure-side heat exchanger, dTc(k) is a value obtained by subtracting the fluid temperature from the condensation temperature of the high pressure-side heat exchanger, Cpr(k) is a specific heat at constant pressure of the refrigerant at the outlet of the high pressure-side heat exchanger, and ΔHcon(k) is a difference of enthalpy at an inlet and an outlet of the high pressure-side heat exchanger.