Recovering waste heat in buildings is a key strategy for improving energy efficiency and reducing remissions. Many building systems, such as cooling equipment, wastewater, and ventilation reject heat that has the potential to be captured and reused in everyday building operations. Mapping these opportunities at the outset ensures that retrofit plans are both efficient, and cost-effective.
This downloadable energy mapping tool builds on our Energy Sources and Sinks Inventory Tool to help project teams identify and quantify recoverable heat through analysis of building-specific data. While it can be applied to any building type, it was created with large commercial and multifamily properties in mind and is geared toward building owners’ staff and consultants leading decarbonization efforts. See instructions below and download the tool to start evaluating your building’s energy recovery potential.
Purpose: Compare building-specific data for source(s) and sink(s) to estimate potential energy recovery. Default assumptions and data are included to streamline the process. The following common use cases are included in the tool:
- Capturing heat rejected by the cooling system to improve space heating system performance.
- Capturing heat rejected by the cooling system to improve domestic hot water (DHW) heating system performance.
- Capturing heat from wastewater to improve domestic hot water (DHW) heating system performance.
- Capturing energy from exhaust air to temperature outside ventilation air.
Phase: This spreadsheet tool is intended to supplement other engineering and financial analysis tools during the Planning phase. Additionally, it is recommended the team review the spreadsheet tool during the Pre-Planning phase and identify data collection needs. This is critical, because if data isn’t already being collected the metering will need to be initiated and data collected over a range of operating conditions (e.g. throughout the winter).
Inputs: Input requirements are dependent on the use case:
Use cases 1 & 2: Short-interval (e.g., hourly) data for source(s) and sink(s) relevant to the energy recovery use case(s) to be evaluated. The data is typically collected using data trending through the building automation system. Additional metering (e.g., thermal energy “BTU” meters) may need to be installed. Data collected should also be reviewed for accuracy and completeness and normalized for factors such as outside air temperature. If data cannot be collected from the building, explore leveraging an energy model for estimates.
Use case 3: Attributes about the building’s occupancy, domestic hot water usage, and wastewater.
Use case 4: Attributes about the building’s air distribution system.
Outputs: Annual load and recoverable heat per use case. Data collection initiated to support future heat mapping.
This spreadsheet is not a comprehensive design tool but can generate inputs for energy and financial analyses used in investment decision making.