Caroline Hedger Apartments

Firm:Globetrotters Engineering Corporation

Other Consultants:Carnow Conibear & Associates, Ltd.

Owner:Chicago Housing Authority

Description:The Caroline Hedger Senior Residence is a 26-story high-rise facility owned and operated by the Chicago Housing Authority (CHA). The building contains first floor offices and 449 apartments located on either side of a central corridor. The rectangular building is oriented East-West and there are no adjacent high-rise structures.

The building was initially heated by three hot-water boilers located on the top floor. The hot water was supplied to in-slab coils in each unit. The boilers, pumps, and controls had been replaced five years prior to the start of the building upgrade. Each residence and office contained through-wall air conditioners for cooling. A gas-fired make-up air unit (MAU) for the corridor supply was located on the roof. The unit was corroded and no longer operated. Temperature control was via thermostats and modulating valves.

The Caroline Hedger Senior Residence was to receive a complete upgrade which included new windows, additional insulation to the outside walls, new kitchen and bathroom facilities, a new emergency generator, and an upgraded HVAC system. For the HVAC system upgrade, the client had several design requirements. For heating, the client wished to abandon the in-slab heating system as the existing pipe was corroded and the controls were failing. For cooling, the client did not want window or through-wall air conditioners. They compressor failure and subsequent replacement of the through-wall units was becoming a significant expense. The client estimated that they were replacing 150 compressors per year which was also straining their maintenance staff. Due to CHA’s limited budget, value engineering was to be considered for every phase of design. Also, due to the work being performed at a senior residence where moving occupants in and out of rooms could cause unnecessary strain, the building would be occupied for the entirety of construction.

The improvement of residents’ quality of life was GEC’s primary focus but implementing reliable and efficient HVAC systems to public housing will save money for the city which can be distributed to other programs. If engineers can show that early investments in HVAC pay off, such as through GEC’s cost analysis, we can lay the foundations for sustainable building designs.

It is a challenge to incorporate modern HVAC equipment into existing buildings that were not built with those systems in mind. This project demonstrates a unique application of existing HVAC technology by creating a manifold for the chilled water system and using that to supply chilled and hot water risers to the building.

Chicago Housing Authority

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