A system for monitoring the operational health of a refrigeration system, comprising: at least one sensor configured to obtain a plurality of measurements from a monitored refrigeration system over a period of time; and at least one control processor located outside the compartment of the refrigeration system configured to: receive the plurality of measurements from the at least one sensor, the plurality of measurements representing at least a current usage by the monitored refrigeration system, and a temperature within a compartment of the monitored refrigeration system; and communicate the plurality of measurements to a monitoring system, wherein the monitoring system is configured to: generate a first characteristic representing a time sequence of current usage by the monitored refrigeration system or temperatures measured within the compartment of the monitored refrigeration system; identify differences between the first characteristic and one or more baseline characteristics, the one or more baseline characteristics including at least one other characteristic previously obtained from a nominally operating refrigeration system; predict failure or loss of energy efficiency of the monitored refrigeration system based on differences identified between the first characteristic and the one or more baseline characteristics; and determine one or more dysfunctions of a thermodynamic cycle based on the differences between the first characteristic and the one or more baseline characteristics, wherein the one or more dysfunctions include a loss of energy efficiency measured with respect to a baseline energy efficiency associated with a plurality of baseline characteristics obtained from a group of refrigeration systems known to be running at nominal or optimal performance levels. at least one sensor configured to obtain a plurality of measurements from a monitored refrigeration system over a period of time; and at least one control processor located outside the compartment of the refrigeration system configured to: receive the plurality of measurements from the at least one sensor, the plurality of measurements representing at least a current usage by the monitored refrigeration system, and a temperature within a compartment of the monitored refrigeration system; and communicate the plurality of measurements to a monitoring system, wherein the monitoring system is configured to: generate a first characteristic representing a time sequence of current usage by the monitored refrigeration system or temperatures measured within the compartment of the monitored refrigeration system; identify differences between the first characteristic and one or more baseline characteristics, the one or more baseline characteristics including at least one other characteristic previously obtained from a nominally operating refrigeration system; predict failure or loss of energy efficiency of the monitored refrigeration system based on differences identified between the first characteristic and the one or more baseline characteristics; and determine one or more dysfunctions of a thermodynamic cycle based on the differences between the first characteristic and the one or more baseline characteristics, generate a first characteristic representing a time sequence of current usage by the monitored refrigeration system or temperatures measured within the compartment of the monitored refrigeration system; identify differences between the first characteristic and one or more baseline characteristics, the one or more baseline characteristics including at least one other characteristic previously obtained from a nominally operating refrigeration system; predict failure or loss of energy efficiency of the monitored refrigeration system based on differences identified between the first characteristic and the one or more baseline characteristics; and determine one or more dysfunctions of a thermodynamic cycle based on the differences between the first characteristic and the one or more baseline characteristics, wherein the one or more dysfunctions include a loss of energy efficiency measured with respect to a baseline energy efficiency associated with a plurality of baseline characteristics obtained from a group of refrigeration systems known to be running at nominal or optimal performance levels.