Blogs

Concrete Evidence of Zero Zone Reliability

In 2002, a severe drought agonized 33% of the contiguous United States. Crops and pastures were ruined, wells ran dry, and reservoirs were drained. In Colorado, over 3 million people lost their water security. Water restrictions were put in place. Outdoor lawn watering, accounting for half of annual residential water use, could only be done once a week and was scheduled by address numbers. Swimming pools could not be filled during one of the warmest summers on record. After the drought broke, planning for the next one became a priority. An expansion project began on Colorado’s Gross Reservoir Dam, located in Boulder County, to prevent water scarcity in the future.

The dam is going to be raised by 131 feet (totaling 471 feet) to increase the reservoir’s capacity by 25 billion gallons of water. After the dam’s expansion, it will be 3 times its current size and the tallest concrete dam in Colorado. Although this project has many challenges, one in particular caught the attention of Zero Zone: the heat concrete produces as it cures.

Project Overview

Adding ice to the concrete mixing process is required to obtain a pour temperature satisfying the dam engineer’s specifications. Temperatures as low as 50°F may be required. Lower pour temperatures reduce the likelihood of cracking during the curing process. Ice offsets the heat of hydration and friction caused by the mixing process when the required temperature cannot be achieved with chilled water alone. 250 tons of ice per day were required to meet this demand for cooling by pumping reservoir water to the icemaking system, storing the ice, and then conveying it to the concrete batching system. After mixing the concrete, a conveyor transfers it to the pour site. The contractor designing the project, TRJ Refrigeration of Oxnard, California, chose Zero Zone to design a rack system that provides refrigeration to part of the icemaking system.

A pump pulls water from the reservoir, and the refrigeration system freezes it before it reaches a conveyor. The conveyor brings the ice to the concrete; it is spread evenly to bring the concrete’s temperature down. The project’s demand for ice could not be met with the current refrigeration system. The owner of the project selected Zero Zone to integrate another system to increase the amount of ice being produced.

Ice Distribution

This video demonstrates how ice is spread over the expansion project's freshly placed concrete.

Challenges of the Project

The construction site posed challenges to system installation. A clear day can quickly turn into a dangerous thunderstorm with flash flooding in the Rocky Mountains. Other hazards, like dynamite blasting, also existed. These conditions would pause installation until it was once again safe for technicians to work.

The Gross Dam is located 29 miles from the nearest town. The remoteness of the location limited communication between field and support teams. The router used for communication was in a fixed location away from the installation site. The router's location prevented field support technicians from being next to the system when communicating. At times, satellite communication was necessary.

The Zero Zone Team

Dallas Schumann, Field Service Technician Supervisor, assisted with installation and startup. He said, “We had to walk into the building with the router to use the phone, so we couldn’t talk to the engineers while we were by the system. The installation went smoothly, and we only needed to call for programming information.” Zero Zone products are designed with ease of installation in mind. Our team is on-site for each installation to provide a worry-free startup, even in the most unique applications.

Due to the unpredictable nature of the construction site, Zero Zone technicians participated in a mandatory safety training course. The video described the hazards they would face and the safety plan for each. The combination of Zero Zone safety practices and on-site training resulted in an injury-free installation.

Although the commute was almost an hour one way, the team showed up each day ready to work. They remained aware of safety concerns and focused on providing a quality startup. The system installed at the Gross Reservoir Dam was finished on time and had a flawless startup.

Zero Zone Solutions

This Zero Zone OPS system’s cooling capacity of 720,000 Btu/h is achieved with 6 reciprocating compressors. A semi-hermetic seal protects the compressors from debris during operation. A panel-mounted CPC E3 controller is used to control the system. The ambient air temperature at the construction site averages 80°F during its hottest month, so the air-cooled condenser is able to dissipate heat from the system effectively. Zero Zone ingenuity can make basic components operate in unique applications.

Zero Zone custom-engineered systems provide you with flexibility to meet your unique needs. The ease of installation and maintenance will ensure the system starts quickly without complications and stays running.

If you are interested in a Zero Zone refrigeration system, visit our products page, or contact a sales rep today.