Internal air adjustment device

1. An internal air adjustment device that adjusts a composition of internal air existing inside a storage, comprising:

a first composition adjustment unit that includes a first separation unit that separates external air existing outside the storage into supply air, having a composition that differs from a composition of the external air, and first remaining air, the first composition adjustment unit supplying the supply air into the storage; and

a second composition adjustment unit that includes a second separation unit that separates internal air existing inside the storage into discharge air, having a composition that differs from the composition of the internal air, and a second remaining air, the second composition adjustment unit discharging the discharge air to outside of the storage,

wherein the supply air and the second remaining air are supplied to the storage via a common supply pipe.

2. The internal air adjustment device according to claim 1 , wherein the first composition adjustment unit supplies the supply air into the storage so that air pressure inside the storage differs from air pressure outside the storage.

3. The internal air adjustment device according to claim 1 , wherein the first composition adjustment unit supplies the supply air into the storage so that air pressure inside the storage becomes positive.

4. The internal air adjustment device according to claim 3 , wherein a flow rate of the supply air that is supplied into the storage by the first composition adjustment unit is higher than a flow rate of the discharge air that is discharged to the outside of the storage by the second composition adjustment unit.

5. The internal air adjustment device according to claim 1 , wherein a carbon dioxide concentration reduction operation of reducing a carbon dioxide concentration of the internal air in the storage is performed by causing the second separation unit of the second composition adjustment unit to separate the discharge air from the internal air existing inside the storage, the discharge air having a carbon dioxide concentration that is higher than the carbon dioxide concentration of the internal air.

6. The internal air adjustment device according to claim 1 , wherein an oxygen concentration reduction operation of reducing an oxygen concentration of the internal air in the storage is performed by causing the first separation unit of the first composition adjustment unit to separate the supply air from the external air existing outside the storage and the second separation unit of the second composition adjustment unit to separate the discharge air from the internal air, the supply air having an oxygen concentration that is lower than an oxygen concentration of the external air, the discharge air having an oxygen concentration that is higher than the oxygen concentration of the internal air.

7. An internal air adjustment device that adjusts a composition of internal air existing inside a storage, comprising:

a first composition adjustment unit that includes a first separation unit that separates supply air from external air existing outside the storage, the supply air having a composition that differs from a composition of the external air, the first composition adjustment unit supplying the supply air into the storage; and

a second composition adjustment unit that includes a second separation unit that separates discharge air from the internal air existing inside the storage, the discharge air having a composition that differs from the composition of the internal air, the second composition adjustment unit discharging the discharge air to outside of the storage,

wherein

an oxygen concentration reduction operation of reducing an oxygen concentration of the internal air in the storage is performed by causing the first separation unit of the first composition adjustment unit to separate the supply air from the external air existing outside the storage and the second separation unit of the second composition adjustment unit to separate the discharge air from the internal air, the supply air having an oxygen concentration that is lower than an oxygen concentration of the external air, the discharge air having an oxygen concentration that is higher than the oxygen concentration of the internal air, and

the internal air adjustment device includes

an oxygen sensor that measures the oxygen concentration of the internal air in the storage; and

a controller that determines whether or not air pressure inside the storage is positive based on a change in a measured value of the oxygen sensor during the oxygen concentration reduction operation, and that, when the controller determines that the air pressure inside the storage is not positive, performs a controlling operation for increasing a flow rate of the supply air that is supplied into the storage by the first composition adjustment unit.

8. The internal air adjustment device according to claim 1 , comprising:

a ventilation exhaust passage for allowing inside and the outside of the storage to communicate with each other; and

a ventilation exhaust valve that is provided in the ventilation exhaust passage.

9. The internal air adjustment device according to claim 1 , wherein the first separation unit separates untreated external air, which is external air introduced from the outside of the storage, into first external air and second external air having different compositions,

the first composition adjustment unit supplies, as the supply air, one of the first external air and the second external air into the storage and discharges other of the first external air and the second external air, as the first remaining air, to the outside of the storage,

the second separation unit separates untreated internal air, which is internal air introduced from inside the storage, into first internal air and second internal air having different compositions, and

the second composition adjustment unit supplies, as the second remaining air, one of the first internal air and the second internal air into the storage and discharges, as the discharge air, other of the first internal air and the second internal air to the outside of the storage.

10. The internal air adjustment device according to claim 9 , wherein the first separation unit is configured to separate the untreated external air into first external air having a nitrogen concentration that is higher than a nitrogen concentration of the untreated external air and an oxygen concentration that is lower than an oxygen concentration of the untreated external air and second external air having a nitrogen concentration that is lower than the nitrogen concentration of the untreated external air and an oxygen concentration that is higher than the oxygen concentration of the untreated external air, and

the second separation unit is configured to separate the untreated internal air into first internal air having a nitrogen concentration that is higher than a nitrogen concentration of the untreated internal air and an oxygen concentration that is lower than an oxygen concentration of the untreated internal air and second internal air having a nitrogen concentration that is lower than the nitrogen concentration of the untreated internal air and an oxygen concentration that is higher than the oxygen concentration of the untreated internal air.

11. The internal air adjustment device according to claim 9 , wherein the first separation unit and the second separation unit are each provided with a gas separation membrane where a passing rate of nitrogen is lower than both a passing rate of oxygen and a passing rate of carbon dioxide,

the first separation unit is configured to bring the untreated external air into contact with the gas separation membrane, cause air that did not pass through the gas separation membrane to be defined as the first external air, and cause air that passed through the gas separation membrane to be defined as the second external air, and

the second separation unit is configured to bring the untreated internal air into contact with the gas separation membrane, cause air that did not pass through the gas separation membrane to be defined as the first internal air, and cause air that passed through the gas separation membrane to be defined as the second internal air.

12. The internal air adjustment device according to claim 11 , wherein the first composition adjustment unit includes a first pump that compresses the untreated external air and supplies the untreated external air to the first separation unit.

13. The internal air adjustment device according to claim 12 , wherein the first composition adjustment unit includes a first valve mechanism that is provided at a pipe where the first external air flows, and that has a variable opening degree.

14. The internal air adjustment device according to claim 11 , wherein the second composition adjustment unit includes a second pump that compresses the untreated internal air and supplies the untreated internal air to the second separation unit.

15. The internal air adjustment device according to claim 14 , wherein the second composition adjustment unit includes a second valve mechanism that is provided at a pipe where the first internal air flows, and that has a variable opening degree.

16. The internal air adjustment device according to claim 9 , wherein the first separation unit includes an adsorption unit that is provided with an adsorbent that adsorbs nitrogen,

the first separation unit is configured to perform an adsorption operation of producing the second first external air by causing nitrogen contained in the untreated external air supplied to the adsorption unit to be adsorbed onto the adsorbent of the adsorption unit, and a desorption operation of producing the first external air by causing nitrogen to be desorbed from the adsorbent of the adsorption unit,

the second separation unit is provided with a gas separation membrane where a passing rate of nitrogen is lower than both a passing rate of oxygen and a passing rate of carbon dioxide, and

the second separation unit is configured to bring the untreated internal air into contact with the gas separation membrane, cause air that did not pass through the gas separation membrane to be defined as the first internal air, and cause air that passed through the gas separation membrane to be defined as the second internal air.

17. The internal air adjustment device according to claim 1 , wherein the first composition adjustment unit includes

a first bypass passage for supplying the external air existing outside the storage into the storage by causing the external air to bypass the first separation unit, and

a first bypass valve mechanism for changing a flow rate of the external air that flows into the first bypass passage.

18. The internal air adjustment device according to claim 1 , wherein the second composition adjustment unit includes

a second bypass passage for supplying the internal air existing inside the storage into the storage by causing the internal air to bypass the second separation unit, and

a second bypass valve mechanism for changing a flow rate of the internal air that flows into the second bypass passage.