Strategic Decarb 101

Terminology & Definitions


Insights from Empire Building Challenge 

The following are terms commonly used in the building decarbonization universe:

Carbon Neutral Buildings:

Buildings that produce no net greenhouse gas emissions directly or indirectly. Carbon neutrality spans multiple scopes of associated greenhouse gas emissions including:operations on-site and via emissions associated with third parties delivering energy or products to site and embodied carbon emissions from the full lifecycle and production of construction materials. Emissions are often referred to as scope 1, 2 and 3. Essentially, scope 1 and 2 are those emissions that are owned or controlled by a company. Meanwhile, scope 3 emissions are a consequence of the activities of the company but occur from sources not owned or controlled by it.

Coefficient of Performance (COP):

The ratio of the amount of heat delivered from a heat pump over the amount of electrical input. For example, a heat pump has a COP of 5.0, if it can deliver 5 units of heat for one unit of electricity input. A COP of 1.0 is typical for resistance heat (e.g., toaster or hair dryer). 

Facade Overclad:

An additional weather barrier installed overtop an existing facade to increase building envelope energy performance, thermal comfort, and to reduce ongoing building maintenance. 

Heat Recovery/Recycling:

The capture and reuse of waste heat often incorporating thermal storage techniques, see Time Independent Energy Recovery (TIER).

Net Present Value (NPV):

An analysis of project cash flow over a set period which incorporates inflation and the time value of money; the “upfront” lifetime value of a project. A positive NPV yields a Return on Investment (ROI).

On-site Fossil Fuel:

Fossil fuel consumed typically via combustion within a building for the purpose of heating, cooling, domestic hot water production, or power generation.

Return on Investment (ROI):

The ratio between net income and savings from a project investment over a set period. ROI is typically presented as a percentage for the period of one year.

Simple Payback:

Economic benefits yielded from investment in a project. Simple payback is typically presented in the time (e.g. years) it takes to recover an investment, but does not consider variations in cash flow over time or the time value of money.

Strategic Decarbonization Assessment (SDA):

A mid- to long-term financial planning method for building owners to manage carbon emissions and energy use.

Thermal Distribution:

The means by which thermal energy is moved throughout a building. This includes moving heat through various heat transfer mediums including but not limited to water, steam, refrigerant gas, or ducted air.

Thermal Energy Network (TEN):

Infrastructure that enables heat sharing through a number of thermal transfer mediums and between heat customers and producers who extract heat from multiple sources using varied technologies.

Thermal Storage:

The storage of thermal energy for later use, utilizing various mediums and technologies.

Waste Heat:

Heat or cooling which is typically rejected to the air and not recovered. Waste heat sources include sanitary sewer heat, heat rejected from air source heat pumps, cooling tower heat, heat lost from ventilation exhaust, steam condensate return, and underground transportation, among others.