What is claimed:1. An opening and closing control system that controls operations of a plurality of inlet ports formed on a casing and positioned in an array arrangement aligned vertically and horizontally so as to be openable; the opening and closing control system being mounted in a vehicle and comprising:an internal environment sensor configured to detect an internal environment of the casing;an external environment sensor that is disposed apart from the casing without being in contact with the casing and configured to detect an external environment of the casing which corresponds to the internal environment of the casing, the external environment sensor being configured as part of an air conditioner system in the vehicle;a controller configured to:receive information of the internal environment and the external environment detected by the internal environment sensor and the external environment sensor; andcontrol opening and closing of the inlet ports in response to difference between the internal environment and the external environment; andan air-sending section configured to send cool air generated in the air conditioner system to the casing.2. The opening and closing control system according to claim 1, wherein the external environment sensor is at least partially surrounded by a fluid which is introduced into the casing through the inlet ports.3. The opening and closing control system according to claim 1, wherein the controller is configured to receive information of the external environment from the external environment sensor via wireless communication.4. The opening and closing control system according to claim 1, wherein the internal environment sensor and the external environment sensor each detect an internal temperature of the casing and an external temperature of the casing, respectively, and the controller controls the inlet ports to open when the external temperature of the casing is lower than the internal temperature of the casing, and controls the inlet ports to close when the external temperature of the casing is higher than the internal temperature of the casing.5. The opening and closing control system according to claim 1, wherein the internal environment sensor and the external environment sensor each detect a dew condensation state inside the casing and a dew condensation state outside the casing, and the controller operates to open and close the inlet ports in response to difference between the dew condensation state inside the casing and the dew condensation state outside the casing.6. The opening and closing control system according to claim 5, wherein the controller controls the inlet ports to open when an inside of the casing is in a dew condensation state and an outside of the casing is not in a dew condensation state, and controls the inlet ports to close when the inside of the casing is not in a dew condensation state and the outside of the casing is in a dew condensation state.7. An opening and closing control apparatus that controls operations of a plurality of inlet ports formed on a casing and positioned in an array arrangement aligned vertically and horizontally so as to be openable, the opening and closing control apparatus being incorporated in an opening and closing control system mounted in a vehicle, the apparatus comprising:an internal environment sensor configured to detect an internal environment of the casing;an external environment sensor that is disposed apart from the casing without being in contact with the casing and configured to detect an external environment of the casing which corresponds to the internal environment of the casing, the external environment sensor being configured as part of an air conditioner system in the vehicle; andan air-sending section configured to send cool air generated in the air conditioner system to the casing,wherein the apparatus further comprises:a controller configured to:receive the internal environment and the external environment detected by the internal environment sensor and the external environment sensor; andcontrol inlet ports in response to difference between the internal environment and the external environment.8. The opening and closing control system according to claim 1, wherein the controller is an electronic circuit or a computer having a CPU and a memory.9. The opening and closing control apparatus according to claim 7, wherein the controller is an electronic circuit or a computer having a CPU and a memory.10. An opening and closing control system that controls operations of a plurality of inlet ports formed on a casing and positioned in an array arrangement aligned vertically and horizontally so as to be operable; the opening and closing control system being mounted in a vehicle and operably connected to an air conditioner system of the vehicle, the opening and closing system comprising:an internal environment sensor configured to detect an internal environment of the casing; anda controller including an electric circuit or a computer having a CPU and a memory;whereinthe controller further includes an environment acquiring section connected via wired or wireless communication to an external environment sensor of the air conditioner system,the external environment sensor is disposed apart from the casing without being in contact with the casing and is configured to detect an external environment of the casing;the controller configured to:receive information of the internal environment detected by the internal environment sensor and the external environment acquired via the environment acquiring section; andcontrol, by the electronic circuit or the computer, opening and closing of the inlet ports in response to difference between the internal environment and the external environment; andif the internal environment is higher than the external environment, open the inlet ports to introduce cool air generated in the air conditioner system to the casing.11. An opening and closing control apparatus that controls operations of a plurality of inlet ports formed on a casing and positioned in an array arrangement aligned vertically and horizontally so as to be operable; the opening and closing control apparatus being incorporated in an opening and closing control system mounted in a vehicle and operably connected to an air conditioner system of the vehicle, the opening and closing control system including an internal environment sensor configured to detect an internal environment of the casing, whereinthe opening and closing control apparatus includes:an electric circuit or a computer having a CPU and a memory;an environment acquiring section connected via wired or wireless communication to an external environment sensor of the air conditioner system,the external environment sensor is disposed apart from the casing without being in contact with the casing and is configured to detect an external environment of the casing,the opening and closing control apparatus is configured to:receive information of the internal environment detected by the internal environment sensor and the external environment acquired via the environment acquiring section; andcontrol, by the electronic circuit or the computer, opening and closing of the inlet ports in response to difference between the internal environment and the external environment; andif the internal environment is higher than the external environment, open the inlet ports to introduce cool air generated in the air conditioner system to the casing.