The Challenge
The building’s heating system consists of new boilers and pumps with VFDs that operate as a constant volume system. Ventilation is provided by heating and ventilating AHUs in the common areas and unit ventilators in the classrooms. Cooling is limited to the office and the new wing. Everything is pneumatically controlled, however most of the heating and ventilation equipment appears to be manually controlled and most are in the OFF position while some systems operate continuously.
The Solution
The objective is to recommission and reconditioning the AHUs and UVs and converting to DDC controls for all pieces of equipment. Savings will be driven by demand control ventilation and variable speed drives on the AHUs using a variable 2‐speed motor.
Costs & Benefits
| Total Cost | $485,186.00 |
| Incentives | $182,517.60 |
| Total kWh Saved | 36,999 |
| Total CCF Saved | 5,537 |
| NI Saved$ | $11,089.00 |
Scope of Work
The retrofit project aims to enhance the efficiency and control of the HVAC system. It involves upgrading the existing 15HP pump system with VFDs by replacing 3-way valves with 2-way valves and installing differential pressure sensors for better modulation. Pneumatic control valves will be substituted with electric valves controlled by a proposed DDC system, eliminating the need for the main air compressor. Additionally, 30 classroom unit ventilators and 11 AHUs will undergo modifications to incorporate 2-way heating valves, thermostats, and DDC actuators for improved control based on occupancy or CO2 levels. Critical exhaust fans will be integrated with associated AHUs, and 7 RTUs will be equipped with economizer sections and controls for fresh air, economizer, and DCV.The project also includes installing new thermostat/controllers throughout common areas for remote access to adjust temperature schedules and other settings.
