A method for exchanging heat, the method comprising: flowing a first fluid through a heat exchanger, the heat exchanger comprising: a plurality of parallel heat transfer plates defining a first set of fluid channels and at least a second set of fluid channels; a first fluid inlet port configured to communicate with the first set of fluid channels; a first fluid outlet port configured to communicate with the first set of fluid channels; a second fluid inlet port configured to communicate with the second set of fluid channels; a second fluid outlet port configured to communicate with the second fluid channels; and a packed distributor located within the first fluid inlet port, the first fluid flowing through the first fluid inlet port, the first set of fluid channels, and the first fluid outlet port; and flowing a second fluid through the second fluid inlet port, the second set of fluid channels and the second fluid outlet port, whereby heat is exchanged between the first fluid and the second fluid via the plurality of parallel heat transfer plates, the first fluid being a mixed refrigerant fluid comprising at least two phases including a vapor and a liquid phase, the mixed refrigerant fluid having a temperature range between -40°C and -220°C, the mixed refrigerant including at least two components whose normal boiling points vary by at least 50°C from the warmest boiling component to the coldest boiling component. flowing a first fluid through a heat exchanger, the heat exchanger comprising: a plurality of parallel heat transfer plates defining a first set of fluid channels and at least a second set of fluid channels; a first fluid inlet port configured to communicate with the first set of fluid channels; a first fluid outlet port configured to communicate with the first set of fluid channels; a second fluid inlet port configured to communicate with the second set of fluid channels; a second fluid outlet port configured to communicate with the second fluid channels; and a packed distributor located within the first fluid inlet port, the first fluid flowing through the first fluid inlet port, the first set of fluid channels, and the first fluid outlet port; and flowing a second fluid through the second fluid inlet port, the second set of fluid channels and the second fluid outlet port, whereby heat is exchanged between the first fluid and the second fluid via the plurality of parallel heat transfer plates, the first fluid being a mixed refrigerant fluid comprising at least two phases including a vapor and a liquid phase, the mixed refrigerant fluid having a temperature range between -40°C and -220°C, the mixed refrigerant including at least two components whose normal boiling points vary by at least 50°C from the warmest boiling component to the coldest boiling component. a plurality of parallel heat transfer plates defining a first set of fluid channels and at least a second set of fluid channels; a first fluid inlet port configured to communicate with the first set of fluid channels; a first fluid outlet port configured to communicate with the first set of fluid channels; a second fluid inlet port configured to communicate with the second set of fluid channels; a second fluid outlet port configured to communicate with the second fluid channels; and a packed distributor located within the first fluid inlet port, the first fluid flowing through the first fluid inlet port, the first set of fluid channels, and the first fluid outlet port; and flowing a second fluid through the second fluid inlet port, the second set of fluid channels and the second fluid outlet port, whereby heat is exchanged between the first fluid and the second fluid via the plurality of parallel heat transfer plates, the first fluid being a mixed refrigerant fluid comprising at least two phases including a vapor and a liquid phase, the mixed refrigerant fluid having a temperature range between -40°C and -220°C, the mixed refrigerant including at least two components whose normal boiling points vary by at least 50°C from the warmest boiling component to the coldest boiling component.