Yes. There are primarily three main ventilation systems available for indoor ranges. All three will have a unit supplying fresh air and a unit to exhaust/filter the bad air. All three can provide heat and A/C and all three can (in most cases) be roof mounted or ground mounted on a concrete pad.
- Recirculation System.
This system provides fresh air in and moves it down range where it is exhausted and rerouted back through a series of pre-filters then HEPA filters before mixing back in with fresh air coming through the supply unit. Pros: The system saves costs on continuously conditioning fresh air (heating or cooling) as it retains the current conditioned air, cleans it and recirculates it back through the system. Cons: The equipment is generally much larger and more expensive to move such a large volume of air through multiple filter banks. Moreover, HEPA filters which have to changed up to twice a year (average) can be very expensive. For roof mounted systems, due to the size and weight of the equipment, special consideration and modifications may be required to the building to support the equipment.
- Purge System.
This system has a unit providing fresh air, air is moved down range to a second system to exhaust the air while filtering out heavy particulates before releasing into the atmosphere. This is considered a “straight through” type system where none of the exhausted air is collected, conditioned and reused. Pros: Smaller equipment is allowed as air is not having to be pushed through large banks of filters thus saving in the initial cost of the equipment. Energy costs may be lower to operate due to the smaller equipment and power requirements. Expensive HEPA filters are not required. Cons: There is a loss of all conditioned air as it is merely passed through and exhausted. Systems installed in extremely warm or cold environments may find conditioning the air through alternative sources to be a losing battle against the laminar air flow of the range system. As a result, energy cost can be higher if heat and/or air conditioning is necessary.
- Energy Recovery Ventilation System.
This system is a hybrid between the recirculation system and the purge system but with a few major differences. Air is supplied and moved down range where the bad air is filtered and exhausted, much like a purge system, but a large portion of the energy from the heated or cooled air is routed back through a coil system and used to help condition fresh air coming in. This is a savings since the system does not have to condition 100% of the fresh air coming in (similar to benefits of a recirculation system) and does so without ever mixing the bad air with the fresh air. Pros: Generally, requires smaller equipment than a recirculation system, thus saving on initial equipment cost and overall power requirements to operate. Does not require expensive HEPA filters as the bad air is never used for human consumption. Smaller equipment requirements mean less weight on buildings for roof mounted systems. Cons: Not a true recirculation system as it does not capture as high of a percentage of the conditioned air energy.