Capacity control and faults in refrigeration systems Investigation of different methods for capacity control; fault simulation Features - practice-oriented model of a commercial refrigeration system - refrigeration and freezing chamber to investigate different methods for capacity control - simulation of twelve faults - two defrosting methods for freezing chamber Learning objectives/experiments - familiarisation with the key devices for changing the refrigeration capacity -- thermostat -- capacity controller -- start-up controller -- evaporation pressure controller -- condensation pressure controller - fault finding in refrigeration system components - effect of refrigerant supercooling - familiarisation with defrosting methods -- electric defrost heater -- hot gas defrosting - representation of the thermodynamic cycle in the log p-h diagram Specification [1] investigation of a refrigeration system with refrigeration and freezing chambers [2] refrigeration circuit with compressor, condenser, capacity controller, start-up controller, combined pressure switch and 2 evaporators in insulated chambers [3] each chamber with solenoid valve, thermostat, thermostatic expansion valve, fan and heat exchanger for refrigerant supercooling [4] refrigeration chamber with evaporation pressure controller [5] freezing chamber with electric defrost heater and hot gas defrosting [6] separate or parallel operation of the chambers via solenoid valves [7] simulation of 12 faults [8] touch panel PC for fault activation, data acquisition, evaluation and representation in the log p-h diagram [9] refrigerant R449A, GWP: 1397 Technical data Compressor - refrigeration capacity: 1640W at -10/50°C - power consumption: 980W at -10/50°C Condenser with fan - volumetric air flow rate: 570m3/h Evaporator transfer areas - refrigeration chamber: 1,12m2 - freezing chamber: 1,88m2 Electric defrost heater: approx. 125W Capacity controller: 0,2...6bar Start-up controller: 0,2...6bar Thermostat: 2x -25...15°C Evaporation pressure controller: 0...5,5bar Refrigerant - R449A - GWP: 1397 - filling volume: 3,21kg - CO2-equivalent: 4,5t Measuring ranges - temperature: 6x -50...50°C; 5x 0...100°C - pressure: 3x -1...15bar; 2x -1...24bar - flow rate: 2x 2...29L/h - power consumption: 0...5kW (compressor) 400V, 50Hz, 3 phases 230V, 60Hz, 3 phases; 400V, 60Hz, 3 phases UL/CSA optional LxWxH: 2420x780x1900mm Weight: approx. 280kg