The Importance of Energy Efficient Engineering
The way a building is constructed is crucial to how capable it is of being environmentally sustainable over time. As a result, energy efficiency engineering has become extremely valuable. Energy-conscious engineers and consultants are tasked with providing technical expertise in the development of energy conservation initiatives associated with energy distribution systems.
In this project, Certus team members led the design of mechanical, controls, plumbing, medical gas, and the electrical systems of a full-service greenfield hospital and remote central plant. In order to maintain sustainability over time and through future expansions, the client tasked us with engineering MEP systems with optimum energy performance.
The LEED Silver certified greenfield hospital is approximately 280,000 square feet, with a 16,000 square foot cancer center attached and an 8,000 square foot, 1,575-ton remote central plant. The hospital includes a two-story diagnostic and treatment block with a pharmacy, lab, surgery, emergency department, kitchen, dining and more. A six-story high-rise patient tower sits on top of the D&T housing medical surgical and intensive care units as well as a dialysis unit. The tower also houses women’s and children’s services including labor and delivery, c-section, and newborn nursery spaces.
Conceptual design started with an analysis of a remote versus and attached central utility plant (CUP). Ultimately the design progressed with a remote CUP that provided utilities to the hospital via an underground utility pathway. The location of the CUP was in close proximity to planned future expansion of the hospital, so careful planning and routing of utilities was required to help ensure future flexibility without unnecessary cost or disruption.
10 month design
8,000 sq ft, 1,575-ton remote central plant
projected energy savings of 340,000 KWH per year
domestic water savings of over 2,000,000 gallons per year
In order to accomplish the energy efficiency targets of the project, we designed a heat recovery chiller system to produce low temperature heating hot water from the heat rejected in chilled water production. This resulted in a projected energy savings of approximately 340,000 KWH per year. In the first year of operation, the total energy savings (gas and electric) exceeded the calculated projected savings. The design also included a cooling coil condensate recovery system to capture the cooing coil condensate from the air handling units and pump it back to the central plant to be used as make-up water to the cooling towers. The mineral free nature of the condensate allowed for higher cycles of concentration for the cooling towers. This resulted in significant chemical treatment savings and domestic water savings of over 2,000,000 gallons per year.
The emergency power system included multiple diesel engine generators paralleled together with provisions for a future engine. The generator plant included built in redundancy and was designed to support cooling on emergency power. The systems were also designed with a remote feature for the facility operator to enter into a demand response program partnering with the local utility company resulting in reduced energy costs for the hospital.
Additional energy conservation measures for the project included lighting power density (LPD) reduction, operating room airflow setback, thermal comfort, energy optimization, and water use reduction through condensate recovery and high efficiency plumbing fixtures.
While achieving LEED Silver certification was very important to the hospital, all design decisions were carefully weighed against real anticipated ROI to ensure the building performed as efficiently as possible under actual operating conditions with an acceptable payback of the first cost. The actual energy use index (EUI) was verified via measurement and verification (M&E) to be 156 kBTU/SF.
The project team was comprised of both design and construction teams and was delivered using a modified integrated project delivery method. The teams worked together seamlessly through the use of shared BIM models and real-time costing collaboration to maximize design and construction efficiencies through Target Value Design. Spending 10 months on design and 24 months on construction, the project was delivered on time, on budget and with optimum energy efficiency in mind.