Brewster Pierce HVAC Upgrade Project

Ventilation and geothermal air conditioning

Original Conditions

  • Unit Ventilators provided heat for each classroom. Each unit ventilator brought outside air directly into the building. The ventilation air was exhausted (in some cases) through bathroom exhaust fans. Units used three way control valves, meaning the pumps ran 100% all the time. Many of the units had control dampers that didn’t operate correctly.

Options considered during energy modeling

  • Original building with code required ventilation
  • Oil boiler with baseboard heat, ERV, demand control ventilation, and dehumidification
  • Pellet boiler with baseboard heat, ERV, demand control ventilation, and dehumidification
  • Water to water heat pump with baseboard heat, ERV, demand control ventilation, and dehumidification
  • *Geothermal water to air heat pumps with ERV, demand control ventilation, and dehumidification

*Only one of these options provides cooling.

Energy Modeling

Design Considerations

  • How long can a system operate?
  • Changing the electrical service to the building.

Let’s get going!

  • How do we design this thing?
  • Existing conditions evaluation
  • No cooling load in the summer- what does this mean for the geothermal system?

Geothermal Heat Pump Technology

Geothermal System Schematic

Construction

  • Bond approved by town! Contractor bid awarded to Thomas Mechanical as the prime contractor. Other contractors on the project:

SPAFFORD AND SONS

Construction duration of 8 weeks!

Three construction phases occur simultaneously.

Construction duration of 8 weeks!

Phase 1: Drilling 12 bore holes and laying pipe to the pump room

Construction duration of 8 weeks!

Construction duration of 8 weeks!

Interior: Connecting wells to pump room.

Construction duration of 8 weeks!

Creating the pump room

Construction duration of 8 weeks!

Phase 2: Interior work

Removal of original unit ventilators

Construction duration of 8 weeks!

The gym as a staging area

Construction duration of 8 weeks!

The hallways as staging areas.

Construction duration of 8 weeks!

Energy recovery ventilators (ERV’s)

Construction duration of 8 weeks!

Installing equipment in new wing

ERV installed through gym wall.

Construction duration of 8 weeks!

Phase 3: Installation of solar panels

How does Sandy clean up after all of this?

Construction photos courtesy of Sandy Heyman

Brewster Pierce HVAC upgrade project 2017 - Google Slides