Supporting Research

A Proven Energy Efficient System

The following information is from the web site of Oak Ridge National Laboratory
www.ornl.gov/sci/roofs+walls/research/detailed_papers/thermal/introduction.html

Our comments are [in brackets].

Conclusions

A new procedure is proposed for comparing the thermal performance differences between diverse types of wall systems. This procedure will ultimately include four elements: whole-wall R-value, thermal mass benefits, airtightness, and moisture tolerance. The whole-wall R-value procedure described in this report should be considered for adoption in the ASHRAE Standard 90.2 (ASHRAE 1993b), MEC (CABO (1995), and HERS (Home Energy Rating System) (DOE 1995). In addition, many of the code compliance documents that are available to show builders how to comply with applicable codes, standards and energy-efficiency incentive programs would benefit by using this whole-wall R-value comparison procedure. The database of advanced wall systems is being assembled on the Internet, (http://www.cad.ornl.gov/kch/demo.html). The whole-wall R-value is a better criterion than the center-of-wall and much better than the center-of-cavity R-value methods used to compare most types of wall systems. The value includes the effect of the wall interface details used to connect the wall to other walls, windows, doors, ceilings and foundations. For builders and building owners to appreciate the added thermal benefits of many of the alternatives to conventional wood-frame wall construction, it is necessary to use a whole-wall R-value. The market focus on clear-wall or even worse center-of-cavity R-value,is misleading and inhibiting the market penetration of high-performance wall systems into the residential construction industry.

The use of a whole-wall R-value could guide decision makers to select wall systems that have whole-wall R-values 25%-50% higher than for wall systems that have significant thermal shorting (high misleading center-of-cavity and clear-wall R-values compared to whole-wall R-value).

Conclusions

Experimental and theoretical analysis of the energy performance of light-weight and massive wall systems was presented in this paper. Dynamic thermal performance of sixteen wall assemblies was investigated for residential buildings and the potential energy savings were presented for ten U.S. climates. It was found that some massive building envelope technologies can help in the reduction of building  annual energies.

Several comparative field experiments have demonstrated that in many U. S. locations, heating and cooling energy demands in buildings containing massive walls of relatively high R-values can be lower than those in similar buildings constructed using equivalent R-value with lightweight wall technologies.

The thermal mass benefit is a function of wall material configuration, climate, building size, configuration, and orientation. From ten analyzed U.S. locations, the most beneficial for application of thermal mass are Phoenix, AZ and Bakersfield, CA.

Comparative analysis of "sixteen" different material configurations showed that the most effective wall assembly was the wall with thermal mass (concrete) applied in good contact with the interior of the building. [CAST-TILT systems].

Walls where the insulation material was concentrated on the interior side, performed much worse [every wall systems with insulation attached on the interior of the wall].

Wall configurations with the concrete wall core and insulation placed on both sides of the wall performed slightly better, [FOAM BLOCKS, ICFs] however, their performance was significantly worse than walls containing a foam core and concrete shells on both sides. [CAST-TILT systems]

Following graphs depict the high performance of the CAST-TILT systems in regards to Energy Savings

• Exterior thermal insulation, interior mass (Intmass) [Cast-tilt SW system]
• Exterior mass, interior thermal insulation (Extmass)
• Exterior mass, core thermal insulation, interior mass, and (CIC) [CAST-TILT systems]
• Exterior thermal insulation, core mass, interior thermal insulation (ICI).

The four types of massive walls above approximate most of the currently used multilayer massive wall configurations. For example, the first two wall configurations may represent any masonry block wall insulated with rigid foam sheathing . The last wall configuration may represent Insulated Concrete Forms (ICF) walls. Therefore, results presented in this work can be used for approximate energy calculations of most massive wall systems.

[The first and third wall configurations described above are the CAST-TILT  and Cast-tilt SW systems. At the time of testing, the Testing Laboratory didn’t know either system existed, yet they are describing the features of CAST-TILT and are making statements that the CAST-TILT systems are superior in energy saving potential.]