Heat transfer apparatus

A refrigerative shelving system comprising

• an actively cooled region;
• a storage region separated from the actively cooled region by a partition;
• and
• at least one removable refrigerative shelving arrangement, each refrigerative shelving arrangement comprising:
• a horizontally-extending heat-absorbing shelf formed from a panel having a first upper main face and a second lower main face, the panel containing a plurality of first passages disposed between the first upper main face and the second lower main face, the passages having a working fluid disposed therein, the passages being configured to convey the working fluid in both liquid and gaseous states around an interior portion of the heat-absorbing shelf, wherein the first passages are formed from internal cavities of the heat-absorbing shelf, the heat-absorbing shelf extending into the storage region of the shelving unit,
• wherein in each refrigerative shelving arrangement each of the first passages has a cross-sectional profile having a depth, an upper phase change portion disposed toward the first upper main face of the panel and a lower drain channel portion disposed toward the second lower main face of the panel, wherein the upper phase change portion of the cross-sectional profile has one or more protruding features formed therein, the protruding features protruding into the passages, and the lower drain channel portion of the cross-sectional profile lacks protruding features, the lower drain channel portion occupying in the range of 10% and 50% of the depth of the cross-sectional profile;
• a condenser in fluid communication with the heat-absorbing shelf, wherein the heat-absorbing shelf and the condenser form a hermetically sealed system configured to allow the working fluid to circulate between the heat-absorbing shelf and the condenser without requiring a compressor to effect such circulation,
• wherein the condenser is contained within the actively cooled region and is elevated relative to the heat-absorbing shelf;
• and
• a backing panel extending vertically from the heat-absorbing shelf, the backing panel forming part of the partition separating the actively-cooled region from the storage region.