| 摘要 |
074196-BWL A controlled space is maintained at a desired set point temperature by adjusting the refrigerant temperature at the evaporator outlet in a refrigeration system, thereby controlling the evaporator effectiveness or capacity which is inversely proportional to the outlet temperature. When the space temperature tends to vary from the desired set point due to a changing heat load, the control system automatically changes the refrigerant flow through the evaporator to establish the evaporator outlet temperature at the control point required to maintain the controlled space at the desired temperature. More specifically, in response to a space temperature increase, the flow rate of the refrigerant increases; and in response to a drop below the set point, the refrigerant flow decreases. Such control of the flow rate is achieved by varying the actuation of an electromechanical valve, such as a solenoid valve, interposed between the condenser and evaporator in the refrigeration system, the valve also serving as the system's expansion device. When the heat load on the evaporator is constant, the refrigerant flow is controlled in order to hold the evaporator outlet temperature fixed at the required control point. |
