A refrigerated case comprising: a body having a refrigerated compartment; a refrigeration system comprising: a refrigerant flowpath; a compressor along the refrigerant flowpath; and a plate fin heat exchanger comprising: a plurality of tube sections (154, 156, 158, 160) extending across an air flowpath, including a first group of sections forming a leading group of tube sections; and means for shielding portions of the fins ahead of the leading group against debris accumulation, wherein the plate fin heat exchanger is a first refrigerant-air-heat exchanger in a cooling mode of operation and is a heat rejection heat exchanger and downstream of the compressor along the refrigerant flowpath; the refrigerated case further comprising: a second refrigerant-air heat exchanger being a heat absorption heat exchanger upstream of the compressor in the cooling mode; and an expansion device along the refrigerant flowpath, downstream of the first refrigerant-air heat exchanger and upstream of the second refrigerant-air heat exchanger in the cooling mode, wherein: the air flowpath passes across the first refrigerant-air heat exchanger; a fan is positioned along the air flowpath; the leading group of the first plurality of tube sections (154, 156, 158, 160) is a leading group in the cooling mode; the case comprises the means for shielding the leading group against debris accumulation in the cooling mode; characterised in that the means comprises a plurality of bars immediately in front of and respectively associated with individual ones of the tube sections of the leading group, at the same height thereas, and each bar extending no more than 15% of the tube diameter above or below the associated tube sections, wherein the heat exchanger is in use with vertically arranged tube sections, and not out of phase therewith; and wherein the bars have trailing ends, and wherein the trailing ends have a positive spacing (S 1) ahead of the associated ones of the tube sections; and the bars have a v-shaped cross-section and wherein the bars have trailing ends having a spacing (S 2) ahead of the fins that is up to 30mm. a body having a refrigerated compartment; a refrigeration system comprising: a refrigerant flowpath; a compressor along the refrigerant flowpath; and a plate fin heat exchanger comprising: a plurality of tube sections (154, 156, 158, 160) extending across an air flowpath, including a first group of sections forming a leading group of tube sections; and means for shielding portions of the fins ahead of the leading group against debris accumulation, wherein the plate fin heat exchanger is a first refrigerant-air-heat exchanger in a cooling mode of operation and is a heat rejection heat exchanger and downstream of the compressor along the refrigerant flowpath; a refrigerant flowpath; a compressor along the refrigerant flowpath; and a plate fin heat exchanger comprising: a plurality of tube sections (154, 156, 158, 160) extending across an air flowpath, including a first group of sections forming a leading group of tube sections; and means for shielding portions of the fins ahead of the leading group against debris accumulation, a plurality of tube sections (154, 156, 158, 160) extending across an air flowpath, including a first group of sections forming a leading group of tube sections; and means for shielding portions of the fins ahead of the leading group against debris accumulation, wherein the plate fin heat exchanger is a first refrigerant-air-heat exchanger in a cooling mode of operation and is a heat rejection heat exchanger and downstream of the compressor along the refrigerant flowpath; the refrigerated case further comprising: a second refrigerant-air heat exchanger being a heat absorption heat exchanger upstream of the compressor in the cooling mode; and an expansion device along the refrigerant flowpath, downstream of the first refrigerant-air heat exchanger and upstream of the second refrigerant-air heat exchanger in the cooling mode, a second refrigerant-air heat exchanger being a heat absorption heat exchanger upstream of the compressor in the cooling mode; and an expansion device along the refrigerant flowpath, downstream of the first refrigerant-air heat exchanger and upstream of the second refrigerant-air heat exchanger in the cooling mode, the air flowpath passes across the first refrigerant-air heat exchanger; a fan is positioned along the air flowpath; the leading group of the first plurality of tube sections (154, 156, 158, 160) is a leading group in the cooling mode; the case comprises the means for shielding the leading group against debris accumulation in the cooling mode; characterised in that the means comprises a plurality of bars immediately in front of and respectively associated with individual ones of the tube sections of the leading group, at the same height thereas, and each bar extending no more than 15% of the tube diameter above or below the associated tube sections, wherein the heat exchanger is in use with vertically arranged tube sections, and not out of phase therewith; and wherein the bars have trailing ends, and wherein the trailing ends have a positive spacing (S 1) ahead of the associated ones of the tube sections; and the bars have a v-shaped cross-section and wherein the bars have trailing ends having a spacing (S 2) ahead of the fins that is up to 30mm.