School automation.
Caroline Cadieux
Marketing Manager
Distech Controls, Inc.
American high school wins
Energy efficiency award
Situation analysis
Connolly High School, located in Tempe, Arizona (USA), won the Governor's Award for Energy Efficiency in 2005.
These prestigious awards are presented annually to public institutions that have demonstrated the greatest optimization of energy use through the implementation of innovative solutions that not only save energy but also increase the comfort of the institutions’ premises.
The award received by Connolly High School was given thanks to the installation of the easyCONTROLS™ system from Distech Controls, Inc., manufactured by Source Refrigeration & HVAC, Inc.
Situation
Connolly High School, built in 1972, is a typical example of schools of that era struggling to manage aging mechanical equipment.
The situation was made worse by the need for renovations and the additional equipment installed later.
Connolly High School did not provide the comfort and air quality required for an educational institution, nor did it meet the energy efficiency requirements of modern buildings in the United States.
Connolly High School is comprised of six separate buildings containing 184,034 square feet of air-conditioned space.
Each building was equipped with its own separate mechanical systems, including air handling units and variable air volume (VAV) chillers.
All ventilation systems were equipped with electric reheat sections.
Control systems included multiple pneumatic and independent direct digital control (DDC) systems.
Without any centralized control and monitoring, the outdated HVAC systems operated inefficiently, resulting in a large number of complaints about insufficient indoor comfort.
To simplify and speed up the entire process and to ensure that the school finds a solution that meets its needs and the available budget, the school administration decided to hold a design competition for several companies specializing in heating, ventilation and air conditioning systems.
This allowed for a quick and high-quality assessment of the school's existing needs.
As a result, several detailed proposals were received, which allowed the school administration to make the optimal choice of the company that performed the work and the automation system used.
Solution
The school administration chose the proposal from Source Refrigeration & HVAC, Inc., a dealer of open control systems manufactured by Distech Controls, Inc..
The solution she proposed focused primarily on indoor air quality and control systems, thereby maximizing comfort in the school premises and reducing overall energy consumption.
An assessment of the condition of the central chillers, cooling towers, and pump systems showed that they were in good technical condition and operating quite efficiently.
As a result, Source Refrigeration & HVAC, Inc. proposed to perform a modification of the existing systems, which included the replacement of all air systems, including:
— Installation of 60 VAV units of variable air flow systems.
— Installation of a heat recovery unit to utilize the heat of exhaust air.
— Repair and cleaning of ventilation units, air conditioning units and air ducts.
— Replacement and repair of valves.
— Installation of frequency converters on all main air handling units.
— Installation of a building automation system based on the easyCONTROLS LONWORKS® solution from Distech Controls, Inc., including 650 control points and 112 controllers. This control system also included:
— A centralized control system based on ECU-88 and EC-12 (programmable controllers that comply with the LONMARK® standard).
— Control system for air handling units based on EC-12, EC-8 and EC-67 (programmable controllers compliant with the LONMARK® standard).
— 85 control systems for ventilation and air conditioning systems with variable air volume based on EC-VAV-L (configurable controllers compliant with the LONMARK® standard).
— Control system for rooftop units based on EC-RTU-L (configurable controllers compliant with the LONMARK® standard).
— Heat consumption meters.
— Lonwatcher LONWORKS network management tool.
— Ability to program the system operation using a plug-in based on LNS® for configuring the operating parameters of various systems and creating special programs.
— User interface with access via browsers, as well as scheduling, plotting and analysis of graphs, managing alarm messages and normal user changes of settings using Echelon® i.LON® 100.
Mike Ellis, of Source Refrigeration & HVAC, Inc., comments: We encountered just about every problem you would expect in a school that is over 30 years old, so we took every possible step in doing the job.
When the job was completed, we made sure the school was the way we wanted it to be for our kids.
A key component of this work was the installation of a control and monitoring system.
It was essential that the school's maintenance staff could monitor and control the status of the various systems to ensure that the school was always supplied with the required quality air and to maintain energy efficiency.
The building automation system used made it possible to implement several key requirements for such systems, namely:
- Providing flexible programming to ensure desired sequences of actions are performed.
- The ability to monitor and control CO2 levels to ensure desired indoor air quality and energy efficiency.
- The ability for users of the system to precisely adjust the comfort levels provided.
- Access via browsers and control all system functions through a specially designed interface (easy to use).
- Create a completely open system, from the controllers to the control software.
Benefits
Connolly High School has now achieved exceptional air quality for its students, as well as significant reductions in energy and equipment maintenance costs.
Energy cost savings in the first six months exceeded $58,000, a 34% reduction over the previous average.
John Dermer, Technical Systems Manager for Tumpey Elementary School District #3, adds, “It’s great that we can now monitor and track CO2 levels in the air…
Winning the Governor’s Award shows that improvements can be made air quality and comfort levels, while achieving significant reductions in energy costs.”