P2S Thought Leadership Series
Next , we spoke to Mechanical Engineer and Studio Leader Scott Newman about his thoughts on mechanical system design and decarbonization . Scott has been designing HVAC systems , doing full-scale energy studies and managing projects for eight years . His experience in the different levels of the educational sector , as well as in commercial facilities , means that he ’ s seen first-hand how client needs have evolved in recent years .
FEATURING Scott Newman
Mechanical Engineer
Scott , what new mechanical equipment and technologies should building owners with carbon reduction goals be excited about ?
Heat recovery is a growing innovation category in the industry . Anything you can do to avoid throwing away BTUs is money saved on utilities and lower electrical demand . Dedicated Outdoor Air Systems that deliver fresh air into buildings can be equipped with exhaust air heat recovery , which uses the building ’ s exhaust to preheat or pre-cool incoming fresh air . Outdoor air heat recovery is widely used in colder climates , but we now see positive paybacks in hot , dry climates . On a recent project in Indio , CA , we saw a payback of under 2 years because the heat recovery allowed us to downsize the DX cooling capacity and improve the energy efficiency . Another exciting technology is wastewater heat recovery , which can boost the efficiency of the heating systems in residential buildings , hotels , and dorms by capturing the energy that is literally going down the drain when occupants shower in the morning .
What challenges do mechanical engineers face when designing systems for owners who want to reduce their carbon footprint ?
Reliability and resilience should be front of mind when designing all-electric buildings . Designers need to understand how heat pumps work and when they do not work , to deliver a functional building with minimal carbon emissions . Capacity and efficiency drop off at low temperatures with heat pumps , so it is essential to consider your design heating conditions to make sure the building is covered under all conditions . Another challenge is the defrost cycle : when heat pumps are heating on a cold day , ice can form on the condenser and the unit must switch to cooling to defrost the coil . For hydronic systems , this may require additional redundancy to cover the load while one unit is defrosting . For DX systems , supplemental electric heaters can be used to avoid dumping cold air into the building during the defrost cycle . Finally , Engineers need to consider the whole carbon cycle when making decisions . Operational carbon from gas used on site is only one form of emissions . It doesn ’ t do any good to hook up a clean building to a dirty grid , and there is an enormous amount of embodied carbon any time you build something new . All the steel and concrete must come from somewhere , after all . An embodied carbon Life Cycle Analysis ( LCA ) can help guide engineers and owners in minimizing the carbon footprint of their projects .
Most clients face financial constraints or need a payback from facility retrofits and upgrades . What cost-effective solutions would you pitch to them ?
Buildings are an investment , no matter the owner . Some clients , like larger educational institutions , have a much longer investment horizon than a commercial real estate company . The best way to improve energy efficiency costeffectively is to time the projects with regular equipment replacements . Rarely does a new solution fully pay back the cost of a piece of equipment , but an investment to upgrade the efficiency of a system instead of replacing it in kind can pay back the incremental cost increase in just a few years . Utilities often have rebate programs to improve those returns further . I advise taking advantage of any incentive programs available and carefully timing your upgrades . For instance , if you are planning a façade or window upgrade and a chiller replacement , do the windows first ( or simultaneously ) to potentially downsize the chiller based on the improved window performance .
8 P2S MAGAZINE WINTER 2025