HVAC Recommedations

The recommended HVAC system is a modular VRF design which provides independent control to each space similar to that which is currently installed (mini-split systems). 

The general scope of work is provided below.  Actual site specific conditions will impact the installation and related supplemental reconstruction. 

The areas impacted by this scope may require asbestos abatement in each of the classrooms and corridors.  Ameresco will conduct preconstruction, independent testing of the impacted areas, and will provide abatement services only as needed to facilitate the installation.

The new HVAC system will be Daikin Variable Refrigerant Volume Air-cooled DX zoned system with individual units in each classroom. The classroom areas will receive conditioned outdoor air from roof-mounted NAUs.   The system includes integrated DDC controls system allowing for individual setpoints and remote monitoring. Summary equipment and installation description:

a. ducted fan coil units (FCUs)

b. heat recovery condensing units

c. neutral air units

d. stand-alone Daikin ITE Enhanced Intelligent Control System to control all new equipment installed including: Touch controller, thermostats, and ethernet connectivity. 

The existing electrical system will be upgraded to a 600 AMP Service.  

FCUs will be ceiling mounted and existing drop ceilings modified to accommodate the installation of the new FCU.

New heat recovery condensing units will be roof mounted on curb rails in strategic locations.  These units convey refrigerant to and from the individual classroom units via copper and/or aluminum piping.   The curb rails and refrigerant piping penetrate the roof and the penetrations will be roofed in to eliminate leaks.  

Outside ventilation air (fresh air as required by code delivered at the rate of 10 CFM per person and 0.12 CFM per SF) will be delivered via the RTUs.  Final CFM will be determined during detailed design.

New FCU are 4-way ceiling mounted cassette units in the classrooms.  These units will be hung from the roof structure with “uni-strut” and all-thread.  The units will lay-in the ceiling grid with 4’x4’ appearance when looking from below.  Each unit will have their own thermostat.  These new units will provide heating and cooling via refrigerant from the condensing units through branch selector boxes.  The units will receive refrigerant from the condensing units via refrigerant piping.  Each FCU has a built-in condensate pump.  A group of condensate drains will be connected and routed to one location.  Each group will be routed to the exterior grade level.   

New Neutral Air Unit will provide all of the outdoor air requirements for the renovated area.  The units have an energy wheel that allows for energy recovery and gas heat/DX cooling for humidity control.  These units will provide pre-treated outdoor air delivered at space temperature.  These units will convey the outdoor air and the unit’s exhaust air via metal ductwork above ceilings and grilles in classroom ceilings.  The ductwork will be extended into each classroom.  These units will be located on the roof in strategic locations on roof curbs that will be roofed into the existing roof.

Piping

a. The refrigerant piping will be rigid or soft copper pipe and/or aluminum pipe.  The piping system will be insulated with ½” elastomeric rubber pipe insulation designed for this application.  

b. All condensate piping will schedule 40 PVC pipe.  

c. All gas piping will be carbon steel pipe - welded indoors or threaded outdoors

Classrooms terminal units will not be removed and will be abandoned in place.  Existing boiler system will be decommissioned and abandoned in place, isolated from the building by a shut off valve.

Classroom ceilings will be removed and reinstalled as needed.  Modifications will be made to accommodate HVAC System.  New ceiling tiles will match as close as possible to existing ceiling tiles.