Evaluating the Energy Savings Potential of Buildings Constructed with Mass Wood Building Envelopes

Lead Performer: Oak Ridge National Laboratory – Oak Ridge, Tennessee
Partner: International Mass Timber Alliance -- Tennessee
DOE Total Funding: $675,000
Cost Share: $75,000
Project Term: October 2021 – September 2024
Funding Type: Cooperative Research and Development Agreement – 2021 Lab Call

Project Objective

Thermal mass moderates indoor temperatures, allowing the heating, ventilation, and air conditioning (HVAC) system to operate more efficiently during peak hours. Cross-Laminated Timber (CLT) and other mass wood products provide thermal mass to the building envelope in a more environmentally friendly form than concrete and steel. However, the influence of CLTs on heating and cooling energy, peak energy demand, and the indoor climate is not well-known. This project seeks to identify the energy-efficiency benefits of mass timber structures. The objectives are to (1) test the thermal performance of mass wall structures in controlled laboratory conditions, (2) validate simulation models to expand performance to natural climatic conditions, (3) isolate the impact of the thermal properties of wood (thermal mass, thermal conductivity, moisture storage) on heating and cooling energy use and peak energy demand, and (4) to optimize the performance.

The project team will test mass timber structures in the laboratory and in the field in different climatic conditions to evaluate the expected energy savings they may provide. The mass timber test cubes with heating and cooling systems will be constructed in five locations representing different climate zones and monitored over two years. Energy usage of the mass timber and typical North American lightweight structures will be compared to establish a new metric for predicting the thermal performance of mass timber assemblies.

Project Impact

This project will demonstrate the effective thermal performance of mass timber building components and help optimize the design of energy-efficient, low-carbon mass timber buildings. The demonstration of the effective thermal performance of mass timber building components will provide a design method for carbon reduction and resource efficiency and evaluate a new experimental protocol to assess the energy benefits of building envelope components based on thermal comfort.

This CRADA helps develop a method to quantify the energy benefits of mass timber structures. The tools proposed in this research address energy and peak demand reduction. It is anticipated that cooling demand can be significantly reduced and postponed into periods beyond the peak demand, thus reducing the need for peak demand cooling load in mass timber buildings by 50%.

Contacts

DOE Technology Manager: Sven Mumme
Lead Performer: Mikael Salonvaara, Oak Ridge National Laboratory