106/108 is between five (5) and ten thousand (10000) feet, such that the pipes can be laid substantially near the facility itself. Where a higher length of pipe(s) 106/108 is used, some of the pipes 108 can be laid in parallel, horizontal orientation and joined with u-shaped elbows 104, as shown in FIG. 1. Other pipes 106 can help the ventilation system achieve the necessary depth and can be buried into the earth in vertical orientation, said pipes 106 being perpendicularly oriented to the parallel pipes 108, as shown in FIG. 2. Alternatively, the length of the pipes 106/108 is preferably between twenty five (25) and twenty five hundred (2500) feet, and in some other embodiments, between one hundred (100) and one thousand feet (1000). The diameter of the pipes can be between three (3) and two hundred and forty (240) inches and/or can be selected to best compliment said fluid length of the pipes 106/108.

The ability to exchange heat through the pipes 106/108 can further depend on the material being used in said pipes 106/108 and/or a diameter of the pipes. For example, the pipes 106/108 comprise a material selected from the group consisting of: (i) steel; (ii) polyvinyl chloride (PVC); (iii) ductile iron; and (iv) a high density poly ethylene (HDPE). Depending on the application, materials used can be and/or can be modified so as to be substantially fireproof. Where less space is available for burying pipes underground and the heat exchange must occur more rapidly between the pipes and the ground, the material selected can thus be selected appropriately.

Still further, in some embodiments, such as those exemplified by FIGS. 4-6, the flexible pipes or connectors 104 and/or the pipes 106/108 can include plates 107, vanes, and/or fins 109 installed in the interior of the flexible pipes. The plates 107, vanes, and/or fins 109 are preferably symmetrically arrayed about a center of the flexible pipes or connectors 104 and/or the pipes 106/108. However, in some embodiments where a symmetric array of plates 107, vanes, and/or fins 109 needlessly obstructs airflow and/or is otherwise impractical to implement, asymmetric configurations for the plates 107, vanes, and/or fins 109 can be used. The plates 107, vanes, and/or fins 109 increase temperature exchange between walls of the flexible pipes or connectors 104 and/or pipes 106/108 and the air passing through the flexible pipes or connectors 104 and/or pipes 106/108. The plates 107, vanes, and/or fins 109 can extend radially inwardly from an outer surface of the flexible pipes or connectors 104 and/or pipes 106/108, which may be an outer circumferential surface (as shown in FIGS. 4-6).

In greater particularity, FIG. 4 shows a cross-section (horizontal plane) of a vertically oriented pipe 106, installed with three symmetrically arrayed plates 107. A similar setup can be used for a flexible pipe or connector 104 and/or for a horizontally oriented pipe 108. In the case of a horizontally oriented flexible pipe and/or connector 104 or a horizontally oriented pipe 108, the cross-section would be a vertical cross-section (similar to an elevation view) rather than a horizontal one.

It is appreciated that any number of plates 107 can be used on the interior of the pipe, depending on the application of the ventilation system 100. For example, FIG. 5 shows a cross-section (vertical plane) of a horizontally oriented pipe 108, installed with eight symmetrically arrayed plates 107. A similar setup can be used for a flexible pipe or connector 104 and/or for a horizontally oriented pipe 106. In the case of a horizontally oriented flexible pipe or connector 104 and/or a horizontally oriented pipe 106, the cross-section would be a horizontal cross-section (similar to a top plan or a bottom plan view) rather than a vertical one.

Alternatively, fins 109 which do not extend all the way through the center of the ducts 104, 106, 108 can be used. The fins 109 attach to the outer surface of the the ducts 104, 106, 108 and extend radially inwardly but do not extend all the way to the center of the the ducts 104, 106, 108.

The installation method of the pipes 106/108 will vary depending on environmental and site conditions as well as building ventilation requirements. Pipes 106/108 can be installed with directional drilling, trench installation, etc.

In at least one implementation of the ventilation system 100, the pipes 106/108 are buried below ground at a depth 110 within the earth at location where the ground temperature is between thirty-five and sixty-five degrees Fahrenheit (35° F.-65° F.) year-round. The system 100 can thus utilize geothermal temperature stability to semi-passively provide temperature controlled air to a space at high air volumes without requiring significant energy usage, thereby allowing for low operating costs. Dampers 111 can also be used to eliminate transfer of high heat or low cold penetrator and otherwise reduce condensation, as shown in FIGS. 7-8. The dampers 111 can include three blades 111B. The dampers 111 can be flange mounted via a flange-mount 111FM. Two flange mounts 111FM can be located at opposite surfaces of the ducts 104, 106, 108. The flange-mounts 111FM preferably include a pair of thermal breaks 111TB, as is shown in the detailed view on the lefthand side of FIG. 7. Said flange-mounts 111FM can be secured to the ducts 104, 106, 108 by way of a jamb 111J.

Such a depth 110, could be, for example, approximately twenty (20) feet, though can vary depending on how warm and/or cold the climate is in the area in which the pipes 106/108 are being buried. The pipes 106/108 are arranged to directly and/or indirectly route to a nearby building 122 from an outdoor space 126 after allowing the air to pass through the pipes which are located underground. As a result, by the time the pipes 106/108 route air from the fluid inlet 102 to the fluid outlet 112 at the outdoor space 126, significant heat exchange has occurred through walls of the pipes 106/108 with the surrounding earth. This can help regulate temperatures within the facility to the same range noted previously, or to an otherwise acceptable range for working conditions within the facility that is slightly broader than the previously noted range. Such a broader range, can be, but is not limited to being above thirty two degrees Fahrenheit and below one hundred degrees Fahrenheit (32° F.-100° F.).

To help control the flow of air from the fluid inlet 102 to the fluid outlet 112 at the outdoor space 126, grille(s) and/or registers can be employed at the fluid inlet 102 and/or the fluid outlet 112. FIGS. 9 and 10A-C show non-limiting example of grille(s) 113G and register(s) 113R1-R3 that can be implemented within the ventilation system 100. The registers 113R1-R3 can optionally include a dampening blade 113B. The grille(s) 113G and register(s) 113R1-R3 can also help prevent animals from entering the ducts 104, 106, 108.

When the outside area in the outdoor space 126 is already within an acceptable operating range direct ventilation can be employed. Such direct ventilation can be accomplished by way of a direct ventilation bypass duct 114 located on an external wall of the facility 122. This means air can be selectively brought in directly from outside without sending it through the below-ground pipes 106/108. In some embodiments, the grilles 113G and register(s) 113R1-R3 of FIGS. 9 and 10A-C are also employed at said direct ventilation bypass duct 114.

The need and/or opportunity for direct ventilation can be manually and/or automatically determined. Automatic determination means can include temperature sensors and thermocouples. In a further example, a single point duct temperature sensor can utilize a precision sensor encapsulated in a stainless steel probe and provides excellent heat transfer, fast response and resistance to moisture penetration.

During operation, when outdoor air is cold (e.g., below freezing), the air passing through the pipes 106/108 cam be heated to an acceptable temperature for the ventilated space (e.g., above freezing). Conversely, when outdoor air is very hot, the system can cool the air as it is provided to the ventilated space 122. Operating the system with direct ventilation reduces fan energy costs in the summer due to lower head pressure exerted on the system fan while also reducing condensation in the pipes. Direct ventilation can thus be used in cold climates where summers are temperate, as the air would be routed through the below-ground pipes when outdoor air is below freezing, but can switch to direct ventilation when outdoor air is above freezing. Likewise, in warm climates that do not reach below freezing, the system 100 can be run only in the summer. Therefore, the system has operational flexibility to meet a variety of conditions and needs.

Such a facility needing to be ventilated 122 can be, but is not limited to being waste, wastewater, and other infrastructure facilities that often require significant amounts of ventilation while avoiding extreme hot or cold temperatures. It is to be appreciated the ventilation system can be more efficient where the room and/or space to be ventilated 122 is not regularly inhabited and/or occupied by humans. In some embodiments, the ventilation system 100 can also be operated in association with a heat recovery ventilation (HRV) or energy recovery ventilator (ERV) to further reduce energy usage and costs, such as the ERV 115 of FIGS. 11-13.

The ERV 115 takes in return air 115RA and sends it back into the ventilation system 100 as supply air 115SA. As shown in FIG. 11, the ERV 115 of can, but is not required to, include an inlet hood 115IH with a birdscreen, an inlet air damper 115IAD, a filter section 115FS, a plenum section 115PS, a face & bypass exchanger 115FBD, a blower motor section 115BMS (also shown in FIG. 13), a gravity relief 115GR for a single blade, a damper motor enclosure 115DME (also shown in FIG. 13), and an exit hood 115EH. As shown in FIG. 12, the ERV 115 can, but is not required to, include an air to air exchanger 115EX, an electrical panel 115EP, a positive pressure deluxe door 115DD, and a service receptacle 115SR. As shown in FIG. 13, the ERV 115 can, but is not required to, include a coil section 115CS and a pipe chase 115PC. However, if it is necessary for humans to occasionally occupy the space, the ventilation system 100 can also be installed with ancillary heating/cooling options, such as an electric, gas, etc. heater that can be turned on for periods of time when individuals may be using the space. An exemplary split system air condition and supplemental cooling system 200 is shown in FIG. 14. An infrared supplemental heating system 300 is shown in FIG. 15. The infrared supplemental heating system 300 can be, but is not required to be, equipped with one or more of the following components (ordered from the lefthand side of the figure to the right): a powercord connection 302, a fitted intake collar 304, a black enameled steel burner control box with an ABS plastic cover 306, a tool-free serviceability while operating access panel 308, a reliable hot surface ignition 310, a sight glass for burner inspection 312, a reflector end caps with clips 314, tube hangers 316, highly polished aluminum reflectors 318, and interlocking swaged radiant tubes 320. This can significantly reduce energy usage and operating costs while alleviating man-made acceleration of climate change.

To help facilitate moving air through the pipes 106/108, an intake fan 116 to pull said air through the pipes 106/108 to the ventilated space 122. Similarly, an exhaust fan 118 can help push air that has been within the building 122 for some time back into the environment 124 to help facilitate the continuous ventilation of air through the building 122. The exhaust fan 118 is preferably installed at a different location in the building 122, such as a location on an opposite side of the building from the intake fan 116. Therefore, the primary use of energy in the ventilation system 100 and moving parts located therewithin are a result of running the fan system 116/118 that is used to pull air through the pipes and through the ventilated space 122.

In some embodiments, the intake fan 116 and/or exhaust fan 118 is a cross-flow or tangential fan, sometimes known as a tubular fan. Such fans are often used in heating, ventilation, and air conditioning (HVAC) systems, especially in ductless split air conditioners. The fan can be long concerning the diameter, so the flow remains approximately two-dimensional away from the ends. The cross-flow fan can employ an impeller with forward-curved blades and/or placed in a housing consisting of a rear wall and a vortex wall. In other embodiments, the intake fan 116 and/or exhaust fan 118 can be an axial-flow fans have blades that force air to move parallel to the shaft about which the blades rotate.

To further help facilitate air moving through the pipes, the ventilation system 100 and/or fans 116/118 themselves can include valves, louvers, and/or at least one other type of fluid gate that allows air being ventilated to bypass at least one sections of the pipes 106/108. For example, the valves employed can control air flow into one or more section of the pipes 106/108, can include stall protection (e.g., by employing a brushless DC motor), can include a bi-directional fail-spring spring return, and be housed within an all-metal housing for durability. The valves can be used to used to control water and glycol solutions to 50 percent in small to large air handling units and central plant applications.