As the commercial HVAC industry shifts toward decarbonization and increased sustainability, the role of mechanical design engineers is evolving rapidly. For new mechanical engineers entering the field, the amount of information to learn can be overwhelming. One critical decision they must acknowledge is how to serve a building's heating loads. This article focuses specifically on hydronic system designs for buildings, providing a high-level comparison of fossil-fuel-fired boilers, electric boilers, and various types of heat pump technologies. Key factors are discussed, such as heating water system temperatures, local regulations, and owner requirements, sustainability goals, availability and cost of site utilities, heat recovery capability, and building location. This is to inform the decision-making road map mechanical engineers create and offer to the building owners as viable options.
The first key factor that readers will want to understand when comparing hydronic heating equipment, is coefficient of performance (COP). The COP equation is shown below. Higher COPs corresponds to increased operating efficiencies.