Government facility design: HVAC and plumbing
Consulting engineers are working on government, state, municipal, federal, correctional and military buildings
Jody W. Baldwin, LEED AP, CEM
Branch Manager, Mid Atlantic Division
Envise, a wholly owned subsidiary of Southland Industries
Christopher Carter, EIT
Associate/Graduate Electrical Engineer
Mark Chrisman, PE, MS
Vice President/Healthcare Practice Director
Gary Krueger, PE, LEED AP BD+C, CM
Vice President and Executive Director
TLC Engineering Solutions
Joshua Meinig, PE
Senior Mechanical Engineer
Brian Pak, PE, LEED AP, BEMP
Senior Mechanical Engineer, Department Lead
CSE: What unique heating or cooling systems have you specified into such projects? Describe a difficult climate in which you designed an HVAC system for a government, state, municipal, federal, correctional and military project.
Krueger: Although not necessarily unique we have seen an increase in variable refrigerant flow and geothermal technologies for HVAC design. Challenging HVAC system design included laboratory design for the Navy for installations in Lima and Iquitos, Peru (located on the Amazon River), which both required unique climate conditions and local construction limitations.
Meinig: On a government project, we specified water source heat pumps, the water was a closed loop circuit that was wrapped around the effluent pipe of a process that maintains a constant temperature. This project also used a solar wall adjacent to the mechanical room to temper the intake air before conditioning.
CSE: What unusual or infrequently specified products or systems did you use to meet challenging heating or cooling needs?
Meinig: On coastal project with high salt content and the area is extremely high I sulfide, we provided a fiber-reinforced plastic cooling tower to use in conjunction with water source heat pump in lieu if air cooled direct exchange systems. On another project, I specified gas-fired instantaneous water heaters in series to provide a hot water loop for four hydrogen sulfide scrubbers.
CSE: How have you worked with HVAC system or equipment design to increase a building’s energy efficiency?
Meinig: By using variable frequency drives, variable speed fans and innovative controls (such as carbon dioxide monitoring).
CSE: What best practices should be followed to ensure an efficient HVAC system is designed for this kind of project?
Krueger: Specification of high-efficiency equipment, energy recovery, VRF, geothermal, chilled water along with energy modeling to demonstrate potential energy savings. Early energy modeling, with the consideration of life cycle cost analysis is most effective approach to integrating energy efficient HVAC design.
CSE: What is the most challenging thing when designing HVAC systems in such buildings?
Krueger: Having the architect understand and appreciate the impact his design decisions have on energy performances. Building orientation and extent of glazing introduce challenges that cannot be readily overcome by building systems design.
Meinig: Thermal comfort. You must use engineering tools (such as computational fluid dynamics) and standards to provide a comfortable environment.
Baldwin: Cost of HVAC has always been a hurdle. Providing adequate fresh air, central plants capable of proper heating and cooling, control systems and maintenance programs are all expensive. Energy efficiency and sustainability are great ideas and we are embracing these merits into many of our projects. But more can be done.
Biophilic designs that encourage us to use the environment that surrounds our buildings can drastically reduce HVAC costs in existing and new structures. As one example, natural ventilation can eliminate or reduce sheet metal, fans, electric energy and noise. Some old buildings still rely on passive ventilation shafts; maybe we can learn something new from those old buildings.