Abstract: An energy analyzer for a refrigeration system including a refrigeration circuit having a compressor, a condenser and an evaporator, and a variable speed drive. A device contains an equation correlating refrigeration system operating performance using a variable speed drive to that of a constant speed drive without requiring the constant speed drive. The equation defines a polynomial expression having different combinations of two variables, the temperature of water entering the condenser, and the ratio defined by the variable speed drive input power divided by the design variable speed drive power. Each of these values is continuously calculated during operation of the refrigeration system. The equation solution correlates to the constant speed input power divided by the design constant speed drive power. From this, energy costs associated with operation of the refrigeration system using the constant speed drive can then be calculated with that of the variable speed drive.

Abstract: An energy analyzer for a refrigeration system includes a refrigeration circuit having a compressor, a condenser and an evaporator, and a first drive type. A memory device contains an equation correlating refrigeration system operating performance using a first drive type to that of a second drive type without requiring the second drive type. The equation defines a polynomial expression having different combinations of two variables, the temperature of water entering the condenser, and the ratio defined by the second drive type input power divided by the design second drive type power. Each of these values is continuously calculated during operation of the refrigeration system. The equation solution correlates to the second drive type input power divided by the design second drive type input power. Energy costs associated with operation of the refrigeration system using the second drive type can then be calculated for comparison with the first drive type.