Energy Efficiency Reference/Refrigeration/Data Collection/Standard Refrigeration Data

Standard Refrigeration Data Commonly used data is listed below in groupings that are specific to each piece of equipment. This data will be referred to later in recommendations. Refrigeration Equipment The data below is equipment specific and divided into categories of General - items generally describing the nature of the equipment, and Observe or Measure - Items that must be observed or measured on site Motor Motor nameplate data will be used in many of the following calculations. Motor - (General) Motor Nameplate Horsepower Efficiency Volts Amps Manufacturer RPM Model Power Factor Compressor The first element to assess is the compressor, which uses the majority of the energy in the cycle. Type of Compressor- (General) Compressor Nameplate Compressor Motor Nameplate Refrigeration Type Performance Compressor Manufacturers provide performance points or curves relating power and tons of refrigeration for various suction and discharge pressures. (Observe and Measure) Compressor Power or Compressor Voltage and Compressor Current: Measure Current at as many operating loads as possible and calculate load factors. Condensing temperature/pressure: From a pressure gauge or computerized display Suction temperature/pressure: From a pressure gauge or computerized display Operating Conditions: Describe the use of the refrigeration system. Examples are summer production, repack graveyard, or barry-shift. Use simple descriptions to relate operating conditions to refrigeration loads. Note the plant hours and designation for each compressor. Type of controls: Modulation Controls, Unloading controls for reciprocating compressors, slide valves are common for screw compressors, on-off is the most simple control arrangement, usually found on small (<5 hp) compressors. Oil Cooling Type: Liquid-injection is most common for screw compressor oil cooling. Small pipes with expansion valves enter ports in the slides of the compressor. Thermosyphon cooling is more efficient and uses a heat exchanger next to the compressor oil sump. Water cooling is common for reciprocating compressor head cooling. Condenser Follow the hot gas line from the compressor to the condenser. Note any medium flowing into and out of the condenser. Type of Condenser - (General) Condenser Manufacturer Name Model Number Fan Motor Namplate Pump Nameplate (be alert for multi-speed motors) (Observe or measure) Number of Fans Number of Pumps Approach Temperature Difference Fan and Pump Power, or Voltages and Currents Ambient Temperature (DB/WB) Fan Type If the fan has more than one speed, be sure to note which is measured. Measure fan use factors for as many operating conditions as possible. Pressure Switch Settings Temperature difference with all fans on between ambient and condensing temperature. Use dry-bulb temperature if unit is air-cooled and wet-bulb for evaporative. Other heat Exchangers. There may be other heat exchangers in the hot gas line for heat recovery or de-superheating Evaporator Follow the hot liquid line from the condenser to the evaporator. The expansion device will be located between the evaporator. Evaporator Manufacturer - (General) Model Number Fan Motor Nameplate Data (be alert for multi-speed motors) Type of Evaporator Number of Evaporators Fan Type Number of Fans Back Pressure Regulator Pressure Frop Pressure Switch Settings Defrost Type Defrost Duration Location Suction Line Insulation Approach Temperature with all fans "On" (Observe or Measure) Fan Power or Fan Voltage Fan Current Note: if the fan has more than one speed, be sure to know which is measured. Temperature in the cooled area. Is it the desired temperature? Insulation. Is the area well insulated? Note the type, size, speed, and insulation thickness of doors on coolers and freezers. Approximate time the doors spend open. Additional sources of energy in refrigerated spaces, such as lights or motors. Other equipment such as receivers and accumulators. Schematics of the refrigeration system are helpful and may be available. Temperature and flow rate of everything in and in contact with the system. Plant personnel may have necessary data logged somewhere. Data to collect later: Bin Weather Data Compressor Performance Data Monthly average weather data is available for major cities. Tables contain average hours for which temperature fall within 5 degrees ranges (bins). Bin weather data is useful in calculations that depend on ambient conditions. We recommend a spreadsheet to perform calculations and summarize results.