The historic Stonewall Building, built circa 1925, is a 12-story building in downtown Birmingham, Alabama. The building went through an extensive renovation converting to office spaces and residential lofts. From an engineering standpoint, it was a challenge to provide heating and cooling on an existing building with limited ceiling space for ductwork.

Project: Stonewall Building

Location: Birmingham, Alabama

Architect: Hendon Huckestein Architects, PC

Engineer: BBG&S Engineering Consultants

Contractor: P&M Mechanical

A Variable Refrigerant Flow System using Gree GMV VRF technology was determined to be the ideal solution to solve this problem.

An additional challenge was the building developer did not allow any HVAC equipment to be on the ground. This required all of the outdoor Gree GMV VRF outdoor units be on the roof of the 12-story building. This resulted in extremely long and complicated refrigeration lines that would typically cause issues for most VRF manufacturers.

Using Gree’s Heat Recovery System, each tenant has individual control of their heating or cooling needs. In addition, the building owner saves on their utility costs due to Gree’s high-efficiency Inverter Variable Speed Compressors. By using a VRF system, not only will this solution contribute to the consistent comfort of the tenants, but at the same time a new improved level of energy efficiency will be achieved. The VRF system has lots to offer in reducing energy consumption because of the DC inverter technology, and the reuse of waste heat that is usually released into the atmosphere. Additional benefits include space saving, by eliminating ductwork; independent space control capability; and quieter operation.

An outstanding team effort that included Tom Barrow Company along with the project architects, engineers, and mechanical contractor, made this project a success.

Equipment Used:

The project consisted of 13 Gree GMV VRF Heat Recovery Condensing Units matched to over 200 indoor air handling units.


  • To provide heating and cooling on an existing building.
  • No equipment could be on the ground.
  • Limited ceiling space for ductwork.


  • Variable Refrigerant Flow System to effectively condition the renovated spaces using Gree GMV VRF technology.