DEVITA’s recommended approach for improving the humidity control in the space is to establish a dehumidification cycle in the system operation. The dehumidification cycle will cool the supply air at the air handling unit down to 55F to remove the excess moisture from the supply air stream. Then the supply air will be reheated to prevent overcooling the gymnasium. To implement this dehumidification, sequence the following scope of work is established: 1) Provide and install a reheat coil in the ductwork near the discharge from the air handling unit. The ductwork routing will require some modifications to create a space for the heater. Heater shall be sized to reheat 16,500 cfm from 55F to 80F with hot water EWT of 140 and LWT of 120. 2) Provide and install hot water supply and return piping, isolation valves in the supply and return, and control valves from the existing hot water piping at the AHU to the new coil. 3) Provide and install two (2) thermostats in the gymnasium for integration into the existing building management for controlling the dehumidification sequence. All wiring shall be concealed on the walls or above ceilings. Control wiring shall be run in conduit. 4) Upgrade the exiting Building Management System to add the following dehumidification sequence. a. When the humidity level in the gymnasium, as measured by the new humidistats, rises above the humidity level setpoint (initially 50%RH – Adjustable) the AHU chilled water valve at the coiling coil shall modulate to provide a leaving air temperature of 53F (adjustable). b. The hot water valve at the reheat coil shall modulate to increase the supply air temp as required to maintain the space temperature setpoint on the exiting room thermostat. c. When the humidity level in the gymnasium, as measured by the new humidistats, falls to 5% below the humidity level setpoint (initially 50%RH – Adjustable) the AHU shall leave the dehumidification mode and modulate supply air temperature to maintain room setpoint temperature. d. If the humidity level in the gymnasium, as measured by the new humidistats, rises 5% above the humidity level setpoint (initially 50%RH – Adjustable) the BMS shall provide a high humidity level alarm and send notification to the following Cleveland County Community College personnel (List shall be adjustable by owner) i. Mark Fox ii. Stephen Matheney iii. TBD
