Continuous Refrigerant Monitoring System at Excel Energy in Denver Delivers

Xcel Energy is headquartered in Minneapolis, Minnesota, and is the largest electrical energy provider in Colorado. The company recently upgraded its refrigerant monitoring systems at its Chilled Water building in downtown Denver, creating an efficient and reliable method for continuous monitoring of refrigerant used in 16 chillers in different locations – while supporting the need for safety, system performance, and reductions in energy and refrigerant costs.

Excel Energy’s Denver District Cooling Building in Denver, Colorado

Excel Energy’s Denver District Cooling Building in Denver, Colorado Excel Energy’s Denver District Cooling Building in Denver, Colorado.

Serving Millions of Customers

In addition to Colorado, Xcel Energy also provides electricity and natural gas to eight states in the Upper Midwest and Southeast. Its thermal energy business began in 1998, but its history as an electrical power supplier began more than 100 years ago in many of the states it serves.

The company serves more than 3.6 million electricity customers and two million natural gas customers. It is a forward-thinking energy company when it comes to providing clean power. It has set a carbon reduction goal of 80% from 2005 levels by 2030 and has an aspirational goal of offering 100% carbon-free electricity to customers by 2050. Xcel Energy currently employs about 12,000 people.


Consistent Refrigerant Monitoring Needed

Refrigerant monitoring updates were needed at its downtown Denver location. The different types of refrigerant monitoring systems in use at the time offered no communications ability among plant locations in the city. The Thermal Energy team was spending time conducting constant walk-throughs of five separate buildings to check the health and functionality of 16 chillers and related mechanical equipment, including the refrigerant.

There was also inconsistent monitoring and the absence of data that could identify leaking refrigerants. This, plus the lack of consistency and reliability in the refrigerant equipment used throughout the plants, made troubleshooting difficult and finding correct spare parts from manufacturers arduous. The result was sub-optimal refrigerant use, monitoring and communications, plus inefficiencies in maintenance and repairs and potential safety issues.  

To address the need for updated monitoring, Xcel Energy installed Multi-Zone Halogen Gas Monitor (HG-MZ) refrigerant monitors at its five locations to monitor the chillers. Each plant has its own HG-MZ monitors and they all communicate with the building automation system, which records levels of refrigerant readings while each plant is continually monitoring for potential refrigerant leaks. The HG-MZ units use an NDIR (Non-Dispersive Infrared) sensor that enables early refrigerant leak detection to 1 parts per million (ppm) and a pump that allows for fast sequential sampling up to 16 points.

refrigerant monitor, Bacharach's HGM-MZ

As a reliable refrigerant monitor, Bacharach's HGM-MZ ensures Xcel Energy chillers remain in good operating condition.

Michael O'Malley, Operations Manager at Xcel Energy’s Thermal Energy Department in Denver, has been with the company for 10 years and has double that experience in operations management.

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