ENERGY EFFICIENT BIOLOGICAL FREEZER WITH VIAL MANAGEMENT SYSTEM
An automated, ultra-low temperature freezer having multiple structural features that reduce heat transfer into the freezer, protect its internal mechanical devices against low temperature mechanical binding of their movements, allow defrosting and autoclaving as a result of only minimal changes to the conventional CO 2 emergency backup system. A group of freezers are arranged so they can simultaneously provide an HVAC function. A vial management system allows biological samples or vials to be automatically placed in and recovered from the freezer and associates the temperature history with each sample or vial that it was subjected to during its storage.
1 . An apparatus including an arrangement of ultra-low temperature freezers for providing both storage for numerous biological samples and HVAC for at least a part of the building in which the freezers are housed, the apparatus comprising:
(a) a plurality of ultra-low temperature freezers each freezer having an enclosed cabinet, a refrigerating apparatus for pumping heat out of the cabinet;
(b) a common heat rejection system comprising
(i) a liquid loop of tubes containing a coolant and connected to the refrigerating apparatus of each of the freezers for transporting rejected heat away from the refrigeration systems;
(ii) a first heat exchanger located exteriorly of the building and connected to the liquid loop of tubes for rejecting heat from the coolant into the atmosphere; and
(iii) a second heat exchanger located within the building and connected to the liquid loop of tubes for rejecting heat from the coolant into the building.
2 . An apparatus in accordance with claim 1 and further comprising at least two valves, one valve connected in series with the first heat exchanger and another valve connected in series with the second heat exchange, the valves being adjustable for varying the coolant flow rates through the heat exchangers.
3 . An apparatus in accordance with claim 2 wherein the coolant is a two phase fluid for forming a thermosiphon.
4 . An apparatus in accordance with claim 1 and further comprising at least two pumps, one pump connected in series with the first heat exchanger and another pump connected in series with the second heat exchange, the pumps having an adjustable flow rate for varying the proportions of coolant flow through the heat exchangers.
5 . A method for heating or cooling an interior space in a building and simultaneously providing storage for numerous biological samples the method comprising:
(a) positioning within the interior space a plurality of ultra-low temperature freezers each freezer having an enclosed cabinet and a refrigerating apparatus for pumping heat out of the cabinet;
(b) transporting a portion of heat rejected from the refrigerating apparatus of each freezer to the exterior of the building; and
(c) transporting another portion of heat rejected from the refrigerating apparatus of each freezer to the interior space of the building.
6 . A method in accordance with claim 5 and further comprising varying the proportions of heat transported to the interior space and the exterior of the building to maintain a constant selected temperature in the interior space.
7 . An ultra-low temperature freezer having an enclosed cabinet including a surrounding wall of thermal insulation having an interior side and an exterior side and a refrigerating apparatus, the freezer also having an inlet pipe for connection at one end to a container that is a source of CO 2 and connected at its opposite end into the freezer, the inlet pipe having a valve interposed in the pipe for controlling the inflow of CO 2 into the freezer, the freezer comprising:
an inline heater also interposed in the pipe for heating inflowing CO 2 to allow the freezer to be defrosted or autoclaved.
8 . An ultra-low temperature freezer in accordance with claim 7 wherein the heater is connected to a heat energy source and has a switch or valve for selectively turning the heat energy source on and off.
9 . A method for defrosting or autoclaving an ultra-low temperature freezer having an enclosed cabinet including a surrounding wall of thermal insulation and a refrigerating apparatus, the freezer also having an inlet pipe for connection at one end to a container that is a source of CO 2 and connected at its opposite end into the freezer, the inlet pipe having a valve interposed in the pipe for controlling the inflow of CO 2 into the freezer, the method comprising:
heating CO 2 during inflow of the CO 2 through the pipe into the freezer for defrosting or autoclaving the interior of the freezer.
10 . A method in accordance with claim 9 wherein the method further comprises heating the CO 2 to a temperature of at least zero degrees C.
11 . A method in accordance with claim 10 wherein the method further comprises heating the CO 2 to a temperature sufficient to kill living organisms within the freezer.