Executive Summary

The Smart Bridge deck heating system has the following characteristics:

• It is hydronic, i.e. a heated fluid is circulated through tubes embedded in the bridge deck,

• It makes use of a ground source heat pump system, which recovers energy stored in the earth, and uses it to heat the fluid circulated through the bridge deck,

• It is automatic, and makes use of local and remote weather stations to forecast potential icing conditions, (the automatic nature of the control has given rise to the informal name "Smart Bridge"),

• It is expected to enhance both safety, by eliminating preferential icing conditions, and bridge deck life, by eliminating the application of salt on the bridge deck, and reducing corrosion of the reinforcing steel.

The concept for the bridge deck heating system came about approximately five years ago, with the idea that two areas of special technical expertise available at Oklahoma State University (OSU) might be combined to increase bridge deck life.

The two areas are:

1. Ground source heat pump systems. OSU has been at the center of ground source heat pump system research and application for over 20 years. The International Ground Source Heat Pump Association (IGPSA) is headquartered at OSU and has trained and certified 1000 installers, and numerous engineers, architects, etc. Three faculty members perform extensive experimental and computational research related to ground source heat pump systems funded by the U.S. Department of Energy, the Electric Power Research Institute, National Rural Electric Coorerative Association, and the Geothermal Heat Pump Consortium,

2. The Oklahoma Mesonet is a collaborative project between Oklahoma State University and the University of Oklahoma. The Mesonet is a network of 110 weather stations distributed throughout Oklahoma. Nearly real-time weather data is available over the Internet. The weather data will be used to aid the forecasting of potential icing conditions. It should be emphasized here that the high density of weather stations will allow us to investigate a range of availability of weather stations, as might be found at various locations throughout the U.S.

In addition to the two areas of special technical expertise, the project takes advantage of OSU expertise in heat transfer, systems simulation, computer software development, corrosion control, concrete structures, and intelligent transportation systems. Where appropriate, we will be partnering with colleagues at the University of Oklahoma to utilize additional expertise in weather forecasting and economic analysis.

As the bridge deck heating system is developed, there will be concurrent technology transfer to state departments of transportation and other designers and users of these systems.

The output from this project will include:

• Guidance for designers of smart bridges in the form of manuals and seminars. The seminars and manuals will cover design practices, optimal design, optimal operation, control strategies, and cost/benefit analysis,

• Guidance for designers in the form of design software. The design software will allow state departments of transportation designers as well as private industry designers to determine required ground loop heat exchanger size and configuration, heat pump sizing, circulating pump sizing, the effects of various control and operating strategies, energy consumption, electricity costs, approximate first costs, life cycle costs, and anticipated bridge deck life extension, and projected cost/benefit ratios,

• Advanced modeling software that can be used for additional research and "what if?" design studies,

• Recommended weather sampling, forecasting, control strategies, and operating strategies,

• Verification of reduced corrosion rates for internal reinforcing steel elements in the heated bridge deck, an assessment of bridge lifetime extension, and an economic analysis of smart bridge systems,

• Technology transfer to professionals including bridge designers and construction managers on the above outputs.

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