The Art of Designing Large-Scale Central Utility Plants
When it comes to the art and science of planning and designing the MEP systems to support a hospital campus, large-scale experience is a determining factor in the type of MEP team you should choose.
With increased size comes an increased need for an experienced team to help ensure that the systems design maximizes performance, minimizes cost, and provides long-term value.
One of our team members served as the principal in charge and led the design for the mechanical, controls, plumbing, and medical gas systems for a new 5,000-ton central plant expansion in North Texas.
The new central utility plant was built to make way for a new patient tower and replace the existing central plant that was over 50 years old. All major services feeding the fully functional hospital were to be demolished and back-fed with the new systems including chilled water, steam, and bulk medical gases. The project required careful planning and close coordination for routing and tie-in of utilities.
The project entailed a 10,000 square foot replacement central plant including 5,000-tons of chilled/condenser water and over 1,000 boiler horsepower high pressure steam plant. Additionally, it included an 8MW, 15kV emergency power plant, bulk oxygen and nitrogen services, and 40,000-gallons of on-site diesel fuel oil for primary service generators and standby service to steam boilers. The major services were also designed with N+1 redundancy.
Five-month design
14-month construction
5,000 ton central plant expansion
Supporting an existing 600,000+ square foot full-service hospital, it was necessary that each step of this central plant expansion was meticulously designed and constructed. This project required the development of a complex phasing plan to build the new plant and simultaneously back-feed the existing central plant. Supporting an existing 24/7 operational hospital, it was crucial to develop a way for the original central plant to sustain support while undergoing construction.
Our team provided technical expertise in high pressure steam system design which included routing steam and condensate return services approximately 600 feet underground alongside new chilled water and medical gas services. The design included provisions for thermal expansion and steam condensate removal and required careful planning with other underground utilities. Some innovative approaches to the mechanical engineering design were provisions for energy recovery systems through a heat pump chiller and related controls to allow increased energy efficiency for the Hospital Campus. In addition, our team’s involvement with the local utility company coordination and chiller selection allowed capital incentives to be realized. The savings discovered permitted additional chiller capacity to be planned which resulted in increased cooling redundancy for the hospital.
Since the hospital had to remain in operation, it was necessary to construct, bring online, and back-feed the services before the original central plant could be abandoned and demolished. Because of this, the timeline to design the central plant was compressed. Early in the project planning phase, the design team collaborated with the pre-construction team through a design assist process. The teams worked together through extensive investigation of location and condition of existing utilities, both visible and hidden underground, in hopes of limiting exposure to unforeseen conditions during construction.
Though our team was challenged with a short time frame and we were working with a structure that was over 50 years old, our design process succeeded in mitigating many of the unknown existing conditions of the plant to ensure a solid infrastructure moving forward.