(19)
(11) EP 2 551 612 A3

(12) EUROPEAN PATENT APPLICATION

(88) Date of publication A3:
26.03.2014 Bulletin 2014/13

(43) Date of publication A2:
30.01.2013 Bulletin 2013/05

(21) Application number: 12177749.4

(22) Date of filing: 25.07.2012
(51) International Patent Classification (IPC): 
F25B 1/10(2006.01)
F25B 31/00(2006.01)
 F25B 9/00(2006.01)
F25B 49/02(2006.01)
(84) Designated Contracting States:
AL AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MK MT NL NO PL PT RO RS SE SI SK SM TR
Designated Extension States:
BA ME

(30) Priority: 29.07.2011 JP 2011166353

(71) Applicant: Mitsubishi Heavy Industries
Tokyo 108-8215 (JP)

(72) Inventors:
  • Hotta, Youhei
    Minato-Ku, Tokyo, 108-8215 (JP)
  • Kimata, Yoshiyuki
    Minato-Ku, Tokyo, 108-8215 (JP)
  • Sato, Hajime
    Minato-Ku, Tokyo, 108-8215 (JP)
  • Goto, Toshiyuki
    Minato-Ku, Tokyo, 108-8215 (JP)

(74) Representative: Intès, Didier Gérard André et al
Cabinet Beau de Loménie 158, rue de l'Université
75340 Paris Cedex 07
75340 Paris Cedex 07 (FR)

   


(54) Supercritical-cycle heat pump


(57) A supercritical-cycle heat pump (1) that employs CO2 refrigerant as a working medium that is provided with an injection circuit (11) for injecting intermediate-pressure refrigerant gas being separated by a gas-liquid separator 6 into a sealed housing (14), having intermediate pressure in the interior thereof, in a multistage compressor (2), a controller (25) is provided, which determines the viscosity of the POE oil (17) on the basis of the solubility of the POE oil (17) in the CO2 refrigerant and temperature of the POE oil (17), the solubility of the POE oil (17) in the CO2 refrigerant being determined by pressure and temperature of intermediate-pressure refrigerant and which controls the pressure of the intermediate-pressure refrigerant by controlling a first electronic expansion valve (5) so that the pressure thereof is controlled within a preset usage limit range in order to keep the viscosity of the POE oil (17) above the certain viscosity zone.







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