Refrigeration apparatus

Abstract

A refrigeration apparatus performs heat exchange on a water tube system having a water inlet tube leading exterior water to a water branching point, first and second branching water tubes extending from the water branching point, and a water outlet tube leading to the exterior from a convergent point of the first and second branching water tubes. Active refrigerant is in a supercritical state in at least part of a refrigeration cycle. The refrigeration apparatus includes a main expansion mechanism connected to an evaporator, first and second compression elements connected by a first refrigerant tube, a first heat exchanger exchanging heat between the first refrigerant tube and the first branching water tubes, second refrigerant tubes connecting the second compression element and the main expansion mechanism, and a second heat exchanger in which the second refrigerant tubes exchange heat with the second branching water tubes and does not exchange heat with the water inlet tube.

1 . A refrigeration apparatus which performs heat exchange on a water tube system having a water inlet tube to lead water supplied from an exterior to a water branching point, first branching water tubes and second branching water tubes extending from the water branching point, and a water outlet tube leading out to the exterior from a convergent point where the first branching water tubes and the second branching water tubes converge, active refrigerant being in a supercritical state in at least part of a refrigeration cycle; the refrigeration apparatus comprising:
 a main expansion mechanism arranged and configured to depressurize the refrigerant;   an evaporator connected to the main expansion mechanism, the evaporator being arranged and configured to evaporate refrigerant;   a first compression element arranged and configured to draw refrigerant that has passed through the evaporator, and to compress and discharge the refrigerant drawn into the first compression element;   a second compression element arranged and configured to draw in the refrigerant discharged from the first compression element and to compress and discharge the refrigerant drawn into the second compression element;   a first refrigerant tube arranged and configured to draw the refrigerant discharged from the first compression element into the second compression element;   a first heat exchanger arranged and configured to perform heat exchange between the refrigerant passing through the first refrigerant tube and the water flowing through the first branching water tubes;   second refrigerant tubes arranged and configured to connect a discharge side of the second compression element and the main expansion mechanism; and   a second heat exchanger arranged and configured to such that refrigerant passing through the second refrigerant tubes
 exchanges heat with the water flowing through the second branching water tubes, and 
 does not exchange heat with the water flowing through the water inlet tube. 
   
     
     
         2 . The refrigeration apparatus according to  claim 1 , further comprising:
 a flow rate ratio adjustment mechanism arranged and configured to adjust a ratio between a quantity of water flowing through the first branching water tubes and a quantity of water flowing through the second branching water tubes.   
     
     
         3 . The refrigeration apparatus according to  claim 2 , further comprising:
 a heating capacity detection unit arranged and configured to detect
 a capacity of the refrigerant passing through the first heat exchanger to heat the water and 
 a capacity of the refrigerant passing through the second heat exchanger to heat the water; and 
   a water distribution quantity control unit arranged and configured to adjust the ratio between the quantity of water flowing through the first branching water tubes and the quantity of water flowing through the second branching water tubes by controlling the flow rate adjustment mechanism in accordance with a ratio between the heating capacities of the first heat exchanger and the second heat exchanger detected by the heating capacity detection unit.   
     
     
         4 . The refrigeration apparatus according to  claim 1 , wherein
 the second refrigerant tubes have a third refrigerant tube connecting the second heat exchanger and the main expansion mechanism; and the refrigeration apparatus further comprises:   a fourth refrigerant tube arranged and configured to connect the evaporator and an intake side of the first compression element;   a third heat exchanger arranged and configured to perform heat exchange between the refrigerant flowing through the third refrigerant tube and the refrigerant flowing through the fourth refrigerant tube;   a third heat exchange bypass tube arranged and configured to connect one end and another end of a portion of the third refrigerant tube that passes through the third heat exchanger; and   a heat exchanger switching mechanism arranged and configured to switch between
 a state in which refrigerant flows through the portion of the third refrigerant tube that passes through the third heat exchanger, and 
 a state in which refrigerant flows through the third heat exchange bypass tube. 
   
     
     
         5 . The refrigeration apparatus according to  claim 4 , further comprising:
 temperature sensory units arranged and configured to sense a value of at least an air temperature surrounding the evaporator or a discharged refrigerant temperature of at least the first compression element or the second compression element; and   a heat exchange quantity control unit arranged and configured to control the heat exchanger switching mechanism and to increase the quantity of refrigerant flowing through the portion of the third refrigerant tube that passes through the third heat exchanger when
 the air temperature is higher than a predetermined high-temperature air temperature when a value sensed by the temperature sensory units is an air temperature, or 
 the refrigerant temperature is lower than a predetermined low-temperature refrigerant temperature when the value sensed by the temperature sensory units is a refrigerant temperature. 
   
     
     
         6 . The refrigeration apparatus according to  claim 1 , wherein
 the second refrigerant tubes have a third refrigerant tube connecting the second heat exchanger and the main expansion mechanism; and the refrigeration apparatus further comprises:   a branching expansion mechanism arranged and configured to depressurize refrigerant;   a fifth refrigerant tube which branches off from the third refrigerant tube and extends to the branching expansion mechanism;   sixth refrigerant tubes extending from the branching expansion mechanism to the first refrigerant tube; and   a fourth heat exchanger arranged and configured to perform heat exchange between refrigerant flowing through the third refrigerant tube and refrigerant flowing through the sixth refrigerant tubes.   
     
     
         7 . The refrigeration apparatus according to  claim 6 , further comprising:
 temperature sensory units arranged and configured to sense a value of at least an air temperature surrounding the evaporator or a discharged refrigerant temperature of at least the first compression element or the second compression element; and   a branched quantity control unit arranged and configured to control the branching expansion mechanism and to increase the quantity of refrigerant passing therethrough when
 the air temperature is lower than a predetermined low-temperature air temperature when the value sensed by the temperature sensory units is an air temperature, or 
 the refrigerant temperature is higher than a predetermined high-temperature refrigerant temperature when the value sensed by the temperature sensory units is a refrigerant temperature. 
   
     
     
         8 . The refrigeration apparatus according to  claim 6 , further comprising:
 a water temperature sensory unit arranged and configured to sense a temperature of water flowing through any position in the water tube system;   a first refrigerant temperature sensory unit arranged and configured to sense a temperature of refrigerant passing through the first refrigerant tube; and   a refrigerant distribution quantity control unit arranged and configured to control the branching expansion mechanism and to increase the quantity of refrigerant passing therethrough when a difference between the temperature sensed by the water temperature sensory unit and the temperature sensed by the first refrigerant temperature sensory unit is less than a predetermined value.   
     
     
         9 . The refrigeration apparatus according to  claim 1 , wherein
 the second refrigerant tubes have a third refrigerant tube connecting the second heat exchanger and the main expansion mechanism; and the refrigeration apparatus further comprises:   a branching expansion mechanism arranged and configured to depressurize refrigerant;   fourth refrigerant tubes connecting the evaporator and an intake side of the first compression element;   a third heat exchanger arranged and configured to perform heat exchange between refrigerant flowing through the third refrigerant tube and refrigerant flowing through the fourth refrigerant tubes;   a fifth refrigerant tube which branches off from the third refrigerant tube and extends to the branching expansion mechanism;   sixth refrigerant tubes connecting the branching expansion mechanism and the first refrigerant tube; and   a fourth heat exchanger arranged and configured to perform heat exchange between refrigerant flowing through the third refrigerant tube and refrigerant flowing through the sixth refrigerant tubes.   
     
     
         10 . The refrigeration apparatus according to  claim 9 , further comprising:
 temperature sensory units arranged and configured to sense a value of at least the air temperature surrounding the evaporator or the discharged refrigerant temperature of at least the first compression element or the second compression element; and   a branched heat quantity control unit arranged and configured to control the branching expansion mechanism and to increase quantity of refrigerant passing therethrough when
 the air temperature is lower than a predetermined low-temperature air temperature when the value sensed by the temperature sensory units is an air temperature, or 
 the refrigerant temperature is higher than a predetermined high-temperature refrigerant temperature when the value sensed by the temperature sensory units is a refrigerant temperature. 
   
     
     
         11 . The refrigeration apparatus according to  claim 9 , further comprising:
 a first heat exchange bypass tube connecting one end and another end of a portion of the first refrigerant tube that passes through the first heat exchanger; and   a bypass switching mechanism arranged and configured to switch between
 a state in which refrigerant flows through the portion of the first refrigerant tube that passes through the first heat exchanger, and 
 a state in which refrigerant flows through the first heat exchange bypass tube. 
   
     
     
         12 . The refrigeration apparatus according to  claim 11 , further comprising:
 temperature sensory units arranged and configured to sense a value of at least an air temperature surrounding the evaporator or a discharged refrigerant temperature of at least the first compression element or the second compression element; and   a bypass control unit arranged and configured to control the bypass switching mechanism and to increase using the quantity of refrigerant flowing through the portion of the first refrigerant tube that passes through the first heat exchanger when
 the air temperature is higher than a predetermined high-temperature air temperature when the value sensed by the temperature sensory units is an air temperature, or 
 the refrigerant temperature is lower than a predetermined low-temperature refrigerant temperature when the value sensed by the temperature sensory units is a refrigerant temperature. 
   
     
     
         13 . The refrigeration apparatus according to  claim 9 , further comprising:
 a water temperature sensory unit arranged and configured to sense a temperature of water flowing through any position in the water tube system;   a first refrigerant temperature sensory unit arranged and configured to sense a for sensing the temperature of refrigerant passing through the first refrigerant tube; and   a water-correspondent refrigerant quantity control unit arranged and configured to cont the branching expansion mechanism and to increase the quantity of refrigerant passing therethrough when a difference between the temperature sensed by the water temperature sensory unit and the temperature sensed by the first refrigerant temperature sensory unit is less than a predetermined value.   
     
     
         14 . The refrigeration apparatus according to  claim 1 , further comprising:
 a first drive unit arranged and configured to drive the first compression element; and   a second drive unit arranged and configured to drive the second compression element independently of the first compression element.   
     
     
         15 . The refrigeration apparatus according to  claim 1 , wherein
 the first compression element and the second compression element have a shared rotating shaft in order to perform compression work by rotatably driving each of the first and second compression elements.   
     
     
         16 . The refrigeration apparatus according to  claim 1 , wherein
 the active refrigerant is carbon dioxide.